i ore out 3 i srs za pe tia - « fe a. ) ia ly aif ed mee: h REPORT OF THE TWENTY-NINTH MEETING or tHe |Z pI <¥/ Raarha » ae SST OR . BN v Ea Ry BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE; HELD AT ABERDEEN IN SEPTEMBER 1859. ‘ LONDON: JOHN MURRAY, ALBEMARLE STREET. 1860. PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET. FLAMMAM. CONTENTS. Oxsects and Rules of the Association .........csseeseceeeeee cence see ens Places of Meeting and Officers from commencement .........s++ece008 Page xvii xXx SEEN SEA COOUNE ) Aiaccsicescontacnece occaae ssenscltc csetercescdernssecwescast, | SOUL Table of Council from commencement ..........0. sseeseesceccereseereses | XXII Officers and Council XXVi Officers of Sectional Committees .........sccesecssseecvseeeeseceseecsereee XXVIi Corresponding Members............. Bete he ott Sol AUR Report of the Council to the General ainintes eaeitancesstnacccecen © MmvEn Report of the Kew Committee Report of the Parliamentary Committee omemien Gar counters eae Recommendations for Additional Reports and Hei in Seidhice Synopsis of Money Grants ............ dank oRbleh aN General Statement of Sums paid for Scientific Faas saNus >qiteaienr Extracts from Resolutions of the General Committee ............00008 Arrangement of the General Meetings ownlddee svabse sdencaees ITE TOSIACE 25.0.5 creti' sgn cece tecce cc ack cavtvescecss sev avcace nee REPORTS OF RESEARCHES IN SCIENCE. Preliminary Report on the Recent Progress and Present State of Organic Chemistry. By Grorce C. Foster, B.A., F.C.S., Late As- sistant in the Laboratory of University College, London ............... Report on the Growth of Plants in the Garden of the Royal Agricul- tural College, Cirencester. By James Buckman, F.S.A., F.L.S., F.G.S. &c., Professor of Natural History, Royal Agricultural College Report on Field Experiments and Laboratory Researches on the Con- stituents of Manures essential to cultivated Crops. By Dr. Auacustus VoeLckeER, Royal Agricultural College, Cirencester............seesseeee Report on the Aberdeen Industrial Feeding Schools. By ALEXANDER Tuomson, Esq., of Banchory .. fea divderstealy On the Upper Silurians of Tides Lasatkehite’s Poancbibcanweh Report on the Results obtained by the Mechanico- Chemical euathina: tion of Rocks and Minerals. By ALpHonsE Gaces, M.R.LA., Cu- rator of the Museum of Irish Industry. ......csccsusseressorsseesoscssoeees a2 xl xlv xlix lii liii lvii lvii lix 22 31 44: 63 65 iv CONTENTS. Experiments to determine the Efficiency of Continuous and Self-acting Breaks for Railway Trains. By Witrram Farreairn, F.RS.. Report of Dublin Bay Dredging Committee for 1858-59. as Pro- fessor J. R. KINAHAN, M.D., F.L.S., M.R.LA.. sen cou Report on Observations of Luminous Meteors, 1858-59. By ihe Ret. Bapven Powe tt, M.A., F.R.S., F.R.A.S., F.G.S., Savilian Professor of Geometry in the University of Oxford . eee Report on a Series of Skulls of various Tribes of Mankind inhabiting Nepal, collected, and presented to the British Museum, by Bryan H. Honeson, Esq., late Resident in Nepal, &c. &c. By Professor Owen, F.R.S., Baperiprendent of the Natural gem Dageesee in the British Museum.. : Report of the gieines tare of ese Maskelem Aa Hardwich, and Llewelyn, on the Present State of our es regarding the Photographic Image... Report of the Belfast Dredging Ssauiiee for 1 1859. Bg Cindi . HynpMAvn, President of the Belfast Natural History and Philoso- phical Society ss canpiee> sens pn enssas nae=eie eae eee Continuation of Report of the Progress of Steam Navigation at Hull. By James Otpuam, Esq. Hull, M:.LC.Bincc,.<25sesesoseeabeacWeeeeaars Mercantile Steam Transport Economy as affected by the Consumption of Coals. By CHARLES seen Chief Tignes ee Dock- yard, Woolwich saat PF Report on the present state of Celestial ‘Phategmpgs in Huglaha ‘By WARREN DE LA Rue, Ph.D., F.R.S., Sec. R.A.S. &. ..ccssscecesees On the Orders of Fossil and Recent ace and their Distribution in Time. By Professor Owen, F.R.S. ..... An On some Results of the Magnetic Survey of Seotland i in mies years 1857 and 1858, undertaken, at the request of the British Assotiation, by the late Joun WELSH, Esq. F.R.S. By Batrour Stewart, A.M. The Patent Laws.—Report of Committee on the Patent Laws. Pree sented by W. FAIRBAIRN; FURS, «.3 sscasbiecias otte aceveeueceeeeeeae Lunar Influence on the Temperature of the Air. By J. Park Har- RISON,, MvAs.issoossi0-scsscanshaeag sencyseboupsieasinds tect sak gee An Account of the Construction of the Self-recording Magnetographs at present in operation at the Kew Observatory of the British Asso- ciation. By BaLrour Stewart, M.A. Se eP eee tase eee eeeseseereessereeseee Report on the Theory of Numbers.—Part I. By H.J.Sreruen pas ete M.A., F.C.S., Fellow of Balliol College, Oxford ....... Report of the Committee on Steam-ship performance . Report of the Proceedings of the Balloon Committee of ‘fe British heii . 289 sociation appointed at ‘the Meeting at Leeds... Preliminary Report on the Solubility of Salts at ee above 100° Cent., and on the Mutual Action of Salts in Solution. By Witx1aM K. Suttivan, Professor of Chemistry to the Catholic University of Ireland, and the Museum of Irish Industry... 81 95 «103 . 116 i . 294 CONTENTS. Vv NOTICES AND ABSTRACTS OF MISCELLANEOUS COMMUNICATIONS TO THE SECTIONS, MATHEMATICS AND PHYSICS. MATHEMATICS. Page Introductory Remarks by the President, the EARL OF ROSSE wesessccscssssseeseeee 1 Mr. R. Campsett on the Probability of Uniformity in Statistical Tables....... 3 Lieut.-Colonel SHortTREDE on Calculating Lumars cssccessessssseneeeeee save tise 4 Professor Hennessy on the Figure of an imperfectly Elastic Fluid............ eee hl ake Professor LinpE Lor, Note on the Calculus of Variations ...... redesdeter seemed 5 Professor J. C. Maxwett on the Dynamical Theory of Gases.........scseeeeeees 9 Abbé Moieno’s Supplement to Newton’s Method of resolving Equations ..... 9 Mr. G. Jounstone Stoney’s Note on the Propagation of Waves .,....cssseeees 9 Mr. J. Smrru on the Relations of a Circle inscribed in a Square ....... souinende 10 Mr. C. M. Witticu on the Angles of Dock-Gates and the Cells of Becs s+... 10 Lieut, Heat, Evecrricity, MAGNETISM. Sir Davip Brewster on a New Species of Double Refraction ..sssescosereseseres 10 ——-—-— on the Decomposed Glass found at Nineveh and other PUIALEGiccseicccocdecsddedccncsascsvocsacsarses Caxensuscgins s+ osa@ienshecishdacotersssies sigan be ay TE Mr. H. Cox on the Submergence of Telegraph Cables .......cscecceesecseeecssecescs 11 Mr. J. P. Gasstor on the Stratified Electrical Discharge, as affected by a Move- Pees SEAL scncccsssicsostcstnctiaren shes tscotas nee raerac-5e etiiciessnasncattsyaaidets ose Ppa Rev. T. P. Dare and J. H. Gtapstone on the Relation between Refractive In- dex and Volume among Liquids........ acide sone shaewaksaMesenen eb clasiscevadan ane =dony Uy Mr. G. F. Harrartneton on the Theory of Light.........ccscscsseeseseeecscesees Soe he a! 2 Mr. J. P. Joure’s Notice of Experiments on the Heat developed by Friction (Io SRS SRRPRBRRGr on soccer seer Osa cosene aUelelesenmetins eo clanslade SEdeCoign coe eee eae ooo. 12 Mr. J. B. Linpsay on the Transmission of Electricity through Water.......... 2 13 Rey. Dr. Luoyp on the Affections of Polarized Light reflected and transmitted PRMIDBIIATCS . ccwencccssechactaecerccnesccesds CAAt pr Concobou Jao-Or a eetiod Basiccean dias 14 Professor J. C. Maxwett on the Mixture of the Coluurs of the Spectrum....... 15 Mr. Muneo Ponrton on certain Laws of Chromatic Dispersion ............ Rests aan ——— on the Law of the Wave-lengths corresponding to certain points in the Solar Spectrum......... Beavers este vnitasansnens saiises sah sea vox shensXe 20 Mr. Joun Situ on the Production of Colour and the Theory of Light ......... 22 Bers 1s, STEWART GUPAMIBUE EICAL , .cesps5u asides sssdncandeusccscusasessvecvenes{véeverse, 23 v1 CONTENTS. Professor J. Taomson on recent Theories and Experiments on Ice at its Melt- INP PONE leoesuoseencadeetaas do Poer ea eEOCOCBCCD Ber rpanctacer cet. SeUcL decadaveedsctee Professor W. THomson on Electrical ‘‘ Frequency ”’ ............ sword aleideictelteeistentcar —, Remarks on the Discharge of a Coiled Electric Cable.. ———_—__———_———— on tthe Necessity for incessant Recording, and for Simultaneous Observations in different Localities, to investigate Atmospheric SICCHTICIi Ys. o-sarcrenessneccccanctsensanevacceers * Cee eee tetra tee e tet eee tessa esas seseee Mr. G. V. Tower on the Cause of Magnetism ....... svacecicaeneesssben Taeprisans(r(s Mr. Joun T. Towson on Changes of Deviation of the Compass on Board Iron Ships by “heeling,” with Experiments on Board the ‘City of Baltimore,’ “ Aphrodite,” ‘ Simla,’ and ‘ Shieve Donard ” ....-........scacssesccsssceoss Reeeeaces Mr. J. J. WALKER on the Iris seen on the Surface of Water........ccseeeees Serers AsTRONOMY. Mr. G. B. Arry on the Present State and History of the Question respecting the Acceleration of the Moon’s Motion............ crennecn Sore cnaecn Sasteore snes Mr. W. R. Birt on the Mid-day Illumination of the Lunar Craters Geminus, Burckhardt, and Bernoulli............ Was die anlig se eeccasiace Gee wedentacaicnasemaeeeecat Sir Davip Brewster on Sir Christopher Wren’s Cipher, containing Three Methods of finding the Longittade v2.2 2.2i5c.00.<0ccssocecueesenetdaveresertestteene Sir ©. Garey on the lsoneitude:,sccc.cs0sceedesnscsssanece ncsveeeeee -caeaeaeies i Professor W. Tuomson on the Reduction of Periodical Variations of Under- ground Temperature, with applications to the Edinburgh Observations........ 54 26 27 28 28 29 29 30 34 34 34 35 36 36 41 43 \ | CONTENTS. Vil Professor TyNDALL on the Establishment of Thermometric Stations on Mont a Blanc..essecereeseees cuahens Se aitaasaer an cave ACAGHS ERO ScOn nee er eae 56 GENERAL Puysics. Mr. J. S. Sruart Giennrz, Proposal of a General Mechanical Theory of PHYSICS ...eecesesscoreeeeee Deetavesesnsceeataacsracstodsscaracsstssesccesceservdgdlerssus sets 58 Rey. Dr. Macvicar on the Philosophy of Physics sessceecsseseeee Sia Ardoonthnc oe 659 InsTRUMENTs, &c. Mr. Joszrru Beck on producing the Idea of Distance in the Stereoscope ....... 61 Mr. A. Craupet on the Stereoscopic Angle .,..scssssseesresessensaseneee aaace amy GL ———_— on the Stereomonoscope ...:..seeeeeeeeeee AED AOCCERROM CONC aiaest. 61 ——__——_——. on the Focus of Object-Glasses .............0008 anda SSCaROTOA aC 61 — on a Changing Diaphragm for Double Achromatic Combina- , TIONS ...eeeeee Pigeiecisaustse=ieatar py es ada gactaclawbins cing ve haedo ya hate saat fe cavenvvsteveve 62 Professor J. Cuerx Maxwe tt on an Instrument for exhibiting the Motions of Saturn’s Rings .....sssseeeeee acgagae EPEC ET TRC PRC Pn PRO TES DOFCETICEECRCCLET 62 Abbé Moreno on a New Photometer ese..-esecsereenee SPARRO Remenenacse tats « 62 M. Ruumx«orrr on a New Electro-Medical Apparatus........+...00 weeses enn asters 68 Abbé Moieno on Becquerel’s Phosphoroscope ......+.. Scododurie seneede apenotinoct 62 on the Phonautograph, an Instrument for registering Simple and Compound Sounds .....-..scccssseesnenesseeneeesstnseseeeesersensessaesesseeceseenees 62 M. Porro’s Portable Apparatus for Analysing Light ...... nadegredodices rennocpaedte 63 Lieut.-Colonel R. SuorTREDE on an Improvement in the Proportional Compass 63 Mr. Tuomas Surron on a New Photographic Lens, which gives Images entirely free from Distortion .........sseeeseeseesesseeeeeeeeseneesnesees acetate ou ates 63 Mr. H. R. Twrntne on the Angular Measurement of the Picture in Painting. 64 CHEMISTRY. Address by Dr. Lyon Prayratrr, President of the Section ..... caeasreososeserseese OD Mr. Bryney on the Solubility of Bone-earth from various Sources in Solutions of Chloride of Ammonium and Common Salt...ssesseeesseseesseserseeseeeeees oe OD Mr. G. B. BuckTon on Pentethyl-stibene........sssscscesescnseereesececssecuseneens 66 Dr. F. Cracz Catvert and R. Jonnson on the Specific Gravities of Alloys... 66 Dr. BraLLosiorzky on the different Points of Fusion to be observed in the Constituents of Granite ......sssseeseeeeeeeneeeereceeeeereres GS civat sab eaneenae saad saceee 08 Dr.F. Crace CatverT on the Formation of Rosolate of Lime on Cotton Fabrics in Hot Climates......sssseecerevers epacoaedsetaeisreeta SCRE aOR rer borbncdns: 68 Dr. Dauzzxx on Crystallized Bichromate of Strontia......-...++. sabiavsperers essere 68 on the Economical Preparation of Pure Chromic Acid....,...+.+++ 68 Dr. Guturiz’s Reports from the Laboratory at Marburg ......+ssesseeeeeeee Ev 6S Dr. J. H. Guapstone on the Fluorescence and Phosphorescence of Diamonds 69 on Photographs of Fluorescent Substances .......+-+++++++ 69 MM. Isoarp and Son on a New Form of Instantaneous Generator of Illumi- nating Gas by means of Superheated Aqueous Vapour and any Hydrocarburet ' whatever.....sseseee i caesreceee ME WYN D POvbdeac dadane ire sceremteeteets erates SESE 69 Mr. J. B. Lawes and Dr. J. H. Gitsert on the Effects of different Manures on the Composition of the Mixed Herbage of Meadow -land ,....secersseseseeree 70 Vili CONTENTS. Dr. S. Macapam on the Analysis and Valuation of Manures sssereeeseserreer ere Rev. Dr. Macvicar on the Organic Molecules and their relations to each other, and to the Medium of Light, illustrated by Models according to the Author’s Theory of the Forms and Structures of the Molccules of Bodies.... Mr. J. M*Donnett on the Action of Air on Alkaline Arsemites ...++ssseeeess oe Abbé Moreno on Corne and Demeaux’s Disinfecting and Deodorizing Powder on Matches without Phosphorus or Poison .......ssseseeereeere “Firs , New Process of Preserving Milk perfectly pure in the Natural State, without any Chemical Agent...... gash act he tasinsnaaes secseceeshannee soseneece Messrs. MuLLicaN and Dow11ne’s Quantitative Estimation of Tannin in some Tanning Materials ......... Wegeesiasisesinas raeesveitaadsieecsuasstessehsisaiasil sascnvecccenen Dr. W. Opurne on Marsh’s Test for Arsenic .....sssesseeeeee Cea sor anode uncon dade and Dr. A. Dupré on the Composition of Thames Water...... on a New Mode of Bread-making....+s0.seseeeeveee suscaecmmainetia Dr. T. L. Putpson on some New Cases of Phosphorescence by Heat......++- tee on the Composition of the Shell of Cardium edule (Common Cockle) ........006 plate neaaciaun seltyerajs se ae ciscleleciaelesttitaaicae ssn seeecaiueeosen Scteeecamaraneeene —________——- on the Composition of a recently-formed Rock on the Coast Of Flanders .......sseesesersenseseseees Waecaesmnayssdapetiiece es: BEOdOOCHN Ie naacoranecd. oe Mr. Frepericx Ransome on Soluble Silicates, and some of their Applications M. Tuomas Szecricxkn’s Notes on the Current Methods for Estimating the Cel- lular Matter, or “ Woody-Fibre,” in Vegetable Food-stuffs ......s0s..s0ee eines Mr. Tuomas Spencer on the Supply and Purification of Water......+++ese+ eae Professor J. TzenNant’s Notes on a Gold Nugget from Australia ....... Ane anoriss M. F. Versmann and Dr. A. Opprnuzim on the Comparative Value of cer- tain Salts for rendering Fibrous Substances Non-inflammable .......+++++e+++ . Professor VorLcKeEr on Combinations of Earthy Phosphates with Alkalies .... Dr. W. Watuace, Account of Experiments on the Equivalent of Bromine —-——-————- on Proposed Improvements in the Manufacture of Kelp .... Mr. Naprer’s New Process of Etching Glass in relief by Hydrofluoric Acid. » (Communicated by Professor G. WILSON) cessseaseuserseeeseeeseesencensonsenves cd Professor Gzorcx WiLson on some of the Stages which led to the Invention of the Modern Air-pump......0 seaceaees enieealetes Oa Becaeeas alsets senate seacenteeeaes GEOLOGY. Introductory Address by the President, Sir C. LYELL sssessessesereeeee sabeananeas Sir Cuartes Lyext on the Occurrence of Works of Human Art in Post-plio- cene Deposits......scesesererer sa0see2 heaiis(eaea ders Rhee sennenenes ar eceeoeccaee ssusssnce Rev. Dr. ANDERSON on Human Remains in Superficial Drift ....sssseeseeeeeerens a on Dura Den Sandstone ..s..ccseeeenees Sorceeteveswanveves sdeoues Mr. W. H. Barry on Tertiary Fossils of India .......scsecsseseeeeesereeees tederaneos SS = on Sphenopteris Hookeri, a new Fossil Fern from the Upper Old Red Sandstone formation at Kiltorkan Hill, in the County of Kilkenny, with some Observations upon the Fish Remains and other associated Fossils from the same locality......sscecssssceecsscreeees Re cancuaereeannts saldces cenneeneee Aes Mr. Wiuu1am Beartie, Notice of a Bone Cave near Montrose...... sjc\ays kare eae Dr. B1aLLoBLoTzxKy on Granite ....... oeNeaniiiey Seuemssr aotiagancnncnne- Aang do ubenoes Dr. Buack on Coal at Ambisheg, Isle of Bute ...secscsecsseverevesceeencenesarancevass Page 72 72 74 74 74 74 75 75 75 76 76 17 77 78 79 83 85 86 88 88 88 88 89 93 93 95 97 97 98 99 100 100 CONTENTS. ix Page Mr. A. Brapy on the Elephant Remains at Ifordecsscressssssssessesrsessecevenseese LOO Sir D. Brewster on a Horseshoe Nail found in the Red Sandstone of Kingoodie 101 Dr. G. Buisr on the Geology of Lower Egypt ...sssssseeceeeeereenees Restrcaeper setts 101 Mr. Joun CLecuorn on the Submerged Forests of Caithness.........seeceeeees « 101 Mr. J. W. Dawson’s Letter to Sir Charles Lyell on the occurrence of a Land Shell and Reptiles in the South Joggins Coal-field, Nova Scotia ......s+00.. 102 Professor DauBeEny on certain Volcanic Rocks in Italy which appear to have been subjected to Metamorphic Action....... Spoohiosaccuideconodennic: Loge cnceacn: bgaC 102 Rev. J. Dineie on the Constitution of the Earth......ssccssccsserseveee davenetean +» 102 Mr. R. Garner and W. Motynevx on the Coal Strata of North Staffordshire, with reference, particularly, to their Organic Remains ...,..ssceserecosersereeere 103 Mr. A, Gerxre on the Chronology of the Trap Rocks of Scotland.........cessesees 106 Dr. Grorce D. Gres on Canadian Caverns .......e0.sseeeees Mt dacouereccsetesions +» 106 Mr. Wiiiram Sypney Grgson on some Basaltic Formations in Northumber- Professor Harkness on Sections along the Southern Flanks of the Grampians 109 —-————— on the Yellow Sandstones of Elgin and Lossicmouth...... 109 Mr. Henry C. Hopes on the Origin of the Ossiferous Caverns at Oreston.... 110 Mr. T. F. Jamieson on the Connexion of the Granite with the Stratified Rocks BIMMUCLCE CNS IILE: vase carerc cesses cocece saneceicusdss Drecessccesesndsereendhocetsernee testes 114 on the Drift Beds and Boulders of the North of Scotland... 114 Mr. E. R. J. Know zs on some Curious Results in the Water Supply afforded by a Spring at Ashey Down, in the Ryde Water-works......s.coecseerereeeseenes 114 Dr. Maccowan on certain Phenomena attendant on Volcanic Eruptions and Earthquakes in China and Japan..........sscsseeeees basa aenencnocecdesodscadcnaseeon: 115 Mr. Joun Miter on the Age of the Reptilian Sandstones of Morayshire...... 115 on some New Fossils from the Old Red Sandstone of Caithness......+.. Peer etaaieis sic hiaicielcle/vuisie dg slevaclate sce waitedan Seat Thar ete Mecteweseunte 115 Mr. Hueu Mircuett on New Fossils from the Lower Old Red Sandstone ... 116 Professor James Nicot on the Geological Structure of the Vicinity of Aberdeen and the North-east of Scotland ............. J siara sin ciclo teetaeeeees wanictees esis Wats sia soe LLG -————_——_. — on the Relations of the Gneiss, Red Sandstone, and Quartzite in the North-west Highlands ...... chin cdettoele ste sire orrlobdedtincr panies ne 119 Mr. D. Pacz on some new Boreal forms—the nearly perfect skeletons of Surf and Eider Ducks, Oidema and Somateria—accompanying the remains of Seals, from the Pleistocene Brick-clays of Stratheden, Fifeshire; nine miles inland, and 150 feet above medium tide-level ............0+ Meeeearecten ae oasiene saauecaveeseviaes 120 on the Structure, Affinities, and Geological Range of the Crusta- cean Family Eurypteride, as embracing the genera Kurypterus, Pterygotus, Stylonurus, Eidothea, and other doubtful Eurypterites from the Silurian, De- vonian, and Carboniferous strata of Britain, Russia, and North America...... 120 Mr. C. W. Pracu on Fossil Fish, new to the Old Red Sandstone of Caithness... 120 Mr. W. Pence ty on the Ossiferous Fissures at Oreston near Plymouth....... 121 Mr. Joun Price on Slickensides.......sseeeees Densaneushieesere evden Vattes Peeves tecctsea Lao M. A. Ravicver on a Fragment of Pottery found in Superficial Deposits in Paris..s..oviacee Biaeeiieiieneitesronccclovcscetevarerecsesocssteviccteeses suueside wensecccecreccen LOS Mr. H.C. Sorby on the Origin of * Cone-in-Cone ’....sseceseesnseeees secsecssessves 124 Rev. W. S. Symonps on some Fishes and Tracks from the Passage Rocks and from the Old Red Sandstone of Herefurdshires.s.ccssssssessevecssveesesessenerseeee 124 x; CONTENTS. Mr. C. G, Tuost on the Rocks and Minerals in the Property of the Marquis of Breadalbane...... Stay CPR Manta =a es ase acdsee taasnresarasne gexasanvepsaisvench eve aeae Mr. J. WYLLIE on some Old Red Sandstone Fossils .ccsessscevecsescsccecssccseneres BOTANY AND ZOOLOGY, inctupinc PHYSIOLOGY. Address by Sir Witttam Jarvine, Bart., President of the Section........+....+ Botany. Dr. Grorcre BENNETT on some Uses to which the Nuts of the Vegetable Ivory Palm (Phytelephas macrocarpa) is applicd....6+ssssceeereeerererenes Aree | Radaeace Dr. Georce Burst on the Failure of Bright-coloured Flowers in Forest Trees to produce Pictorial Effect on the Landscape, unless accompanied by abund- ance’of Green Leaves: J. ccecsrccecscesesn=vae8sece0¥osrscyaysisusehualscnces soueeCpeenan ess , Note on some Peculiarities of the Silk Trees or Bomba- wese.of Western Undia) acess. -eunewensnncr sess oesn deters caiahanaian ah eenamenreaecaa ——_—— , Note on the Aversion of certain Trees and Plants to the Neighbourhood of each other .......sesesssecsereveeecerseseeerseeseeeeeecesenes Teasewes Mr. H. Caunter on a Diatomaceous Deposit found in the Island of Lewis ... Mr. Crout’s Account of the more remarkable Plants found in Braemar ........ Professor Dicx1z, Notes on the Upper Limits of Cultivation in Aberdeenshire , Remarks on the Flora of Aberdeenshire ...,..-+e.s.see00 Riees Mr. E. J. Lowe on the Temperature of the Flowers and Leaves of Plants....... Dr. M‘Gowan, Remarks on the Cultivation of the Opium Poppy of China .... Mr. Maxwett T. Masters, Remarks on Vegetable Morphology and the Theory of the Metamorphosis of Plants......... dude ce cneleds deemesenensi seine eatisles Mr. W. E. C. Nourse on the Colours of Leaves and Petals.........+..+0+ pote ree Dr. GrorcE OciLvi& on the Vegetative Axis of Ferns ......+e+eeeee ivavetceamwactey Mr. Grorcre Rainey on the Structure and Mode of Formation of Starch- granules, according to the principles of Molecular Science.....sssessseeeeeveeeene Mr, James Taytor, Notes on the Arctic Flora .....c:.ssscseessececeeenenees eseacege Mr. DanirL VauGHAN on the Growth of Trees in Continental and Insular (CLG ICE ease haeciot seacobo ndadonddo cco hdcécdagoorcdadancepas popeeneegae ey sees svescnngeen ZooLoey. Dr. Apams on the Birds of Banchory......ccsesssecseeesereeeeeeees Sea caeereeee aaanemrre Mr. Josuua ALDER ona New Zoophyte, and two Species of Echinodermata new TOMES LULA a coweieaclec esis meee sn sienieiesh eee ctetle ete eeereaeneeetaleiaa nou b.slels om cies(asne eee Professor ALLMAN on Dicoryne stricta, a New Genus and Species of the Zubu- (EAS TTIN Cora ep An ciaer caRcrconr Ee encnnicsiaer Sache pS anscenaa ar egsenr anocseanoer Achrne asco sagas Aerie On Laomeded tenuis, 0. SPpseresseerseceasseecaceeeenences sisee easels on a remarkable Form of Parasitism among the Pycnogo- MLAB! sano age sas natseanan ss shaparasaesacn seas semce o's Maigeniedalcnatsl cle smeMngennas caps Sam eeecual on the Structure of the Lucernariad@.......++++« Peer Dee nea Dr. Breexer, Descriptions of Genera of Fish of Java ......0++ aiwsteunagaee eee _ Mr. S. M. Burnert, Personal Observations on the Zoology of Aberdeenshire. Mr. Georce Busx, List of Marine Polyzoa collected by George Barlee, Esq., in Shetland and the Orkneys, with Descriptions of the New Species......+..++ Dr. Dickie, Remarks on the Mollusca of Aberdeenshire ....s.ccccscsseneeeeeeceees Page 125 126 126 130 130 132 133 133 133 133 134 135 136 136 138 139 140 140 140 142 142 142 143 143 143 144 144 144 147 CONTENTS. xi Dr. Dicx1e on the Structure of the Shell in some Species of Pecten ..........4.. 147 Mr. Joun Goutp on the Varieties and Species of New Pheasants recently introduced into England...........ssseseseeseeees speaec “Andostoastonannassadra prattsae . 148 on some New Species of Birds.......sssssssssesscceesseseees SP LE) Mr. Joun Hoae, Account of a Species of Phalangista recently killed in the County of Durham.,............sscsesesereeee denideteaexer AS aBanac Roscoe Ae Cont DAnBacEre 149 Mr. T. F. Jamizson, List of the Birds of the North of Scotland, with their Tai Olestdedcccdentsastrusssqecsccrosccserecees sss aRateragevcncer erties tssmpecarcueee cs 150 Dr. James M‘Batn, Notice of a Skull of a Manatee from Old Calabar ......... 150 , Notice of the Duration of Lifein the Actinia Mesembryanthemum MNERUKE Ph INCONANEMENE iE ONUAA “M ‘AMY OL ‘oa “OWI ‘uoysuyor Iossajorg see e cere eee e tees ee eneeeeeeeees erpegeare gy bs ‘Kqjag uyor xnveptig hs ; iz Ran) 2 P t ‘ggg WON ‘mat bees ebesaeeeeeenereseesees tom Ggareg GunoomeH UOUIAA *A\ ‘AY ILL St Pea GTN Oa 3 ‘om “ST a ‘Mosuepy gos cee eee ere teeteceereeeesesers yegey Hour g ‘MUByIN” jo doysig oq. 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(2) ad DR o i) Ss H 4 ke 45 , te Se | a nN Rs Be 3s Bees 1 . JB fe 3 Badd gr gh ZN 8 8 2M SARC oUTst A Sem 8S oH Se re PAS ES ai gad4542 rua BAG HESS gAR eae aS MA ce ere BA a Se SE LSE Za > Pore Eo 9:5 fe] @ a ne ion = io} a {AB ow BoE Ss Saag 9a shay og PS SO gi arte oon eee CHEN FO Ze HHLSS Bis 80's so 5 8 Ho? aBO ode Se eee ce 2 gSEee' O° oh” Hg Peg 2 ea SSS 2.40.8 a OD MoS WS wee ea aes a | AP Saaeaasenseaas GO OO YD ——4F RFR ARsARAAR q ae . & gee wi oe Be ey See | eo oy Be oe ee % 2m igi Ne eee = 1 GZ Pree t oe aT aAge tg {mad MG EMA Sf aR ard Aba geen gma ge aa Faqs > sx -A SO TSR: Tan) 5 od =e ae, 6AG = 23 EOE ZOOS BoA He soa Bk HET eR BeGehe eee BAe ga oa ee ghoa Sore cla se Sore AAR kA tog sesso S333 FAs ee ws S35354 2454444 Biddell, George Arthur, Esq. Bigge, Charles, Esq. Blakiston, Peyton, M.D., F.R.8. Boileau, Sir John P., Bart., F.R.S. Boyle, Rt.Hon. D., Lord Justice-Gen!. (dec*). Brady,The Rt. Hon. Maziere, M.R.1.A., Lord Chancellor of Ireland. Brand, William, Esq. Breadalbane, John, Marquis of, K.T., F.R.S. Brewster, Sir David, K.H., D.C.L., LL.D., F.RB.8., Principal of the University of Edinburgh. Brisbane, General Sir Thomas M., Bart., K.C.B., G.C.H., D.C.L., F.B.S. ° Brooke, Charles, B.A., F.R.S. Brown, Robert, D.C.L., F.R.S. (deceased). Brunel, Sir M. I., F.R.S. (deceased). Buckland, Very Rey. William, D.D., F.R.8., Dean of Westminster (deceased). Bute, John, Marquis of, K.T. (deceased). Carlisle, George Will. Fred., Earl of, F.R.8. Carson, Rey. Joseph, F.T.C.D. Cathcart, Lt.-Gen., Earl of, K.C.B., F.R.S.E. (deceased). Chalmers, Rev. T., D.D. (deceased). ~ Chance, James, Esq. Chester, John Graham, D.D., Lord Bishop of. Christie, Professor 8. H., M.A., F.R.S. Clare, Peter, Hsq., F.R.A.8. (deceased). Clark, Rev. Prof., M.D., F.R.8. (Cambridge.) Clark, Henry, M.D. Clark, G. T., Esq. Clear, William, Esq. (deceased). Clerke, Major §., K.H., R.E., F-R.S. (dec*). Clift, William, Esq., F.R.S. (deceased). Close, Very Rev. F., M.A., Dean of Carlisle. Cobbold, John Chevalier, Esq., M.P. Colquhoun, J. C., Esq., M.P. (deceased). Conybeare, Very Rey. W. D., Dean of Llan- daff (deceased). Cooper, Sir Henry, M.D. Corrie, John, Hsq., F.R.S. (deceased). Crum, Walter, Esq., F.R.S. Currie, William Wallace, Esq. (deceased). Dalton, John, D.C.L., F.R.S. (deceased). Daniell, Professor J. F., F.R.S. (deceased). Dartmouth, William, Earl of, D.C.L., F.R.S. Darwin, Charles, Esq., M.A., F.R.8. Daubeny, Prof. Charles G. B., M.D., F.R.S. DelaBeche, Sir H. T., C.B., F.R.S., Director- Gen. Geol. Surv. United Kingdom (dec®). Devonshire, William, Duke of, M.A., F.R.S. Dickinson, Joseph, M.D., F.R.8. Dillwyn, Lewis W., Esq., F.R.8. (deceased). Drinkwater, J..E.,-Esq. (deceased). Ducie, The Earl, F.R.S. Dunraven, The Earl of, F.R.S. ~ Egerton, Sir P. de M. Grey, Bart., M.P., E.R.S. Eliot, Lord, M.P. Ellesmere, Francis, Earl of, F.G.8. (dec*). Enniskillen, William, Earl of, D.C.L., F.R.S. Estcourt, T. G. B., D.C.L. (deceased). Faraday, Professor, D.C.L., F.R.S. Fitawilliam, The Earl, D.C.L., F.R.S. (dec*). Fleming, W., M.D. Fletcher, Bell, M.D. Foote, Lundy E., Esq. Forbes, Charles, Esq. (deccased). Forbes, Prof. Edward, F.R.8. (deceased). Forbes, Prof. J. D., F.R.8., Sec. R.8.2. Hox, Robert Were, Exsq., F.R.S. Frost, Charles, F.8.A. Gassiot, John P., Esq., F.R.S. Gilbert, Davies, D.C.L., F.R.S. (deceased). Gourlie, William, Esq. (deceased). Graham, 'T., M.A., F.R.S., Master ofthe Mint. Gray, John E., Hsq., Ph.D., F.B.8. Gray, Jonathan, Esq. (deceased). Gray, William, Esq., F.G.S. - Green, Prof. Joseph Henry, D.C.L., F.R.S. Greenough, G. B., Esq., ¥.R.S. (deceased). Griffith, Sir R. Griffith, Bt:, LL.D., M.R.1.A. Grove, W. R., Hsq., M.A., F.R.S. Hallam, Henry, Esq., M.A., F-R.S. (dec!). Hamilton, W. J., Esq., F.R.S., For. Sec. G.S. Hamilton, Sir Wm. R., LL.D., Astronomer Royal of Ireland, M.R.1.A., F.R.A.S. Hancock, W. Neilson, LL.D. Harcourt, Rev. Wm. Vernon, M.A., F.R.S. Hardwicke, Charles Philip, Harl of, F.R.S. Harford, J. 8., D.C.L., F.R.S. Harris, Sir W. Snow, F.R.S. Harrowby, The Earl of, F.R.S. Hatfeild, William, Esq., F.G.S. (deceased). Henry, W. C., M.D., F.R.8. [Col., Belfast. Henry, Rev. P.8., D.D., President of Queen’s Henslow, Rey. Professor, M.A., F.L.S. Herbert, Hon. and Very Rey. Wm., LL.D., F.L.S., Dean of Manchester (dec*). Herschel,Sir John F. W., Bart.,D.C.L., F.R.S. Heywood, Sir Benjamin, Bart., F.R.S8. Heywood, James, Hsq., F.R.S. Hill, Rev. Edward, M.A., F.G8. Hincks, Rev. Edward, D.D., M.R.1.A. Hinds, 8., D.D., late Lord Bishop of Norwich. Hodgkin, Thomas, M.D. Hodgkinson, Professor Eaton, F.R.S, Hodgson, Joseph, Esq., F.R.S. Hooker, Sir William J., LL.D., F.R.S. Hope, Rev. F. W., M.A.; F.R.S. Hopkins, William, Esq., M.A., F.R.S. Horner, Leonard, Esq., F.R.S., F.G.S8. Hovenden, V. F., Esq., M.A. Hutton, Robert, Esq., F.G.S. Hutton, William, Esq., F.G.S. Ibbetson, Capt. L.L. Boscawen, K.R.E.,F.G.8. Inglis, Sir R. H., Bart., D.C.L., M.P. (dec*). Inman, Thomas, M.D. Jacobs, Bethel, Esq. Jameson, Professor R., F.R.S. (deceased). Jardine, Sir William, Bart., F.R.S.E. Jeffreys, John Gwyn, Esq., F.R.S. Jellett, Rev. Prof. Jenyns, Rey. Leonard, F.L.S8. Jerrard, H. B., Esq. Johnston, Right Hon. William, late Lord Provost of Edinburgh. Johnston, Prof. J.B. W., M.A., F.R.S8. (dec). Keleher, William, Esq. (deceased). Kelland, Rey. Professor P., M.A. Kildare, The Marquis of. Lankester, Edwin, M.D., F.R.S. Lansdowne, Hen., Marquisof, D.C.L.,F.B.8. Larcom, Lt.-Colonel, R.E., LL.D., F.R.8. Lardner, Rey. Dr. (deceased). Lassell, William, Heq., F.R.S. L. & E. Latham, R. G., M.D., F.R.8. Lee, Very Rey. John, D.D., F.R.S.E., Prin- cipal of the University of Edinburgh. (deceased), Lee, Robert, M.D., F.R.8. Lefevre, Right Hon. Charles Shaw, late Speaker of the House of Commons. Lemon, Sir Charles, Bart., F.R.8, Liddcll, Andrew, Esq. (deceased). Lindley, Professor John, Ph.D., F.R.8. Listowel, The Earl of. {Dublin (dec*). Lloyd, Rev. B., D.D., Provost of Trin. Coll., Lloyd, Rev. H., D.D., D.C.L., F. B.S. L&E. Londesborough, Lord, F.R.8. Lubbock, Sir John W., Bart., M.A., F.R.S. Luby, Rey. Thomas. Lyell, Sir Charles, M.A., F.R.8. MacCullagh, Prof., D.C.L., M.R.I.A. (dec*). MacDonnell, Rev. R., D.D., M.R.1.A., Pro- vost of Trinity College, Dublin. Macfarlane, The Very Rey. Principal. (dec*). MacGee, William, M.D. MacLeay, William Sharp, Esq., F.L.S. MacNeill, Professor Sir John, F.R.S8. Malahide, The Lord Talbot de. Malcolm, Vice-Ad. Sir Charles, K.C.B. (dec*). Maltby, Edward, D.D., F.R.S., late Lord Bishop of Durham (deceased). Manchester, J. P. Lee, D.D., Lord Bishop of. Marshall, J. G. Esq., M.A., F.G.S8. May, Charles, Esq., F.R.A.S. Meynell, Thomas, Esq., F.L.S. Middleton, Sir William F. F., Bart. Miller, Professor W. A., M.D., F.R.S. Miller, Professor W. H., M.A., F.R.S. Moillet, J. D., Esq. (deceased). Milnes, R. Monckton, Esq., D.C.L., M.P. Moggridge, Matthew, Esq. Monteagle, Lord, F.R.8. Moody, J. Sadleir, Hsq. Moody, T. H. C., Esq. Moody, T. F., Esq. Morley, The Earl of. Moseley, Rey. Henry, M.A., F.R.S. Mount-Edgecumbe, ErnestAugustus, Karl of. Murchison, Sir Roderick I.,G.C. St.8., F.R.S. Neill, Patrick, M.D., F.R.S.E. Nicol, D., M.D. Nicol, Rey. J. P., LL.D. Northampton, Spencer Joshua Alwyne, Mar- quis of, V.P.R.S. (deceased). Northumberland, Hugh, Duke of, K.G.,M.A., F.R.S. (deceased). ’ Ormerod, G. W., Esq., M.A., F.G.S. Orpen, Thomas Herbert, M.D. (deceased). » Orpen, John H., LL.D. Osler, Follett, Esq., F.R.S. Owen, Professor Richd.,M.D., D.C.L.,F.R.S. Oxford, Samuel Wilberforce, D.D., Lord Bishop of, F.R.8., F.G.8. Palmerston, Viscount, G.C.B., M.P. Peacock, Very Rey. G., D.D., Dean of Ely, F.R.S. (deceased). Peel, Rt.Hon.Sir R.,Bart.,M.P.,D.C.L.(dec"). . Pendarves, EH. W., Esq., F.R.S. (deceased). * Phillips, Professor John, M.A., LL.D.,F.R.S. Pigott, The Rt. Hon. D. R., M.R.1.A., Lord Chief Baron of the Exchequer in Ireland. - Porter, G. R., Esq. (deceased). Powell, Rey. Professor, M.A., F.R.S. Prichard, J. C., M.D., F.R.S. (deceased). Ramsay, Professor William, M.A.. Ransome, George, Esq., F.L.S. ‘Reid, Maj.-Gen. Sir W., K.C.B., R.E., F.R.S. "ee gS Rendlesham, Rt. Hon. Lord, M.P. Rennie, George, Esq., F.R.S. Rennie, Sir John, F.R.S. Richardson, Sir John, M.D., C.B., ¥.R.8. Ripon, Har! of, F.R.G.S. , Richie, Rey. Prof., LL.D., F.R.8. (dec*). Robinson, Rey. J., D.D. Robinson, Rey. T. R., D.D., F.R.AS. Robison, Sir John, Sec.R.S.Edin. (deceased). Roche, James, Esq. Roget, Peter Mark, M.D., F.RB.8. Ronalds, Francis, F.R.8. Rosebery, The Earl of, K.T., D.C.L., F.RB.S. Ross, Rear-Ad. Sir J.C., R.N., D.C.L., F.B.S. Rosse, Wm., Earl of, M.A., F.R.S., M.R.LA. Royle, Prof. John F., M.D., F.R.S. (dec*). Russell, James, Esq. (deceased). Russell, J. Scott, Esq., F.R.S. [V.P.R.S. Sabine, Maj.-Gen., R.A., D.C.L., Treas. & Sanders, William, Esq., F.G.S. Scoresby, Rey. W., D.D., F.R.S. (deceased). Sedgwick, Rev. Prof. Adam, M.A., F.R.S. Selby, Prideaux John, Esq., F.R.S.E. Sharpey, Professor, M.D., Sec.R.S. Sims, Dillwyn, Esq. Smith, Lieut.-Colonel C. Hamilton, F.R.S. Smith, James, F.R.S. L. & EB. Spence, William, Esq., F.R.S. (deceased). Stanley, Edward, D.D., F.R.S., late Lord Bishop of Norwich (deceased). Staunton, Sir G. T., Bt., M.P., D.C.L., F.R.S. St. David's, C.Thirlwall,D.D.,LordBishop of. Stevelly, Professor John, LL.D. Stokes, Professor G. G., Sec.R.8. Strang, John, Esq., LL.D. Strickland, Hugh B., Hsq., F.R.S. (deceased). Sykes, Colonel W. H., M.P., F.R.S. Symonds, B. P., D.D., Vice-Chancellor of the University of Oxford. Talbot, W. H. Fox, Esq., M.A., F.R.S. Tayler, Rey. John James, B.A. Taylor, John, Hsq., F.R.S. Taylor, Richard, Hsq., F.G.S. Thompson, William, Bsq., F.L.S. (deceased). Thomson, Professor William, M.A., I’.R.8. Tindal, Captain, R.N. (deceased). Tite, William, Esq., M.P., F.R.S. Tod, James, Hsq., F.R.S.E. Tooke, ‘Thomas, F.R.S. (deceased). Traill, J. §., M.D. (deceased). Turner, Edward, M.D., F.R.S. (deceased). Turner, Samuel, Esq., F.R.S., F.G.8. (dec*). Turner, Rey. W. Tyndall, Professor, F.R.S. Vigors, N. A., D.C.L., F.L.8. (deceased). Vivian, J. H., M.P., F.R.S. (deceased), Walker, James, Hsq., F.R.S. Walker, Joseph N., Hsq., F.G.S. Walker, Rev. Professor Robert, M.A., F.R.8. Warburton, Henry, Hsq.,M.A., F.R.S.(dec*). Washington, Captain, R.N., F.R.S. Webster, Thomas, M.A., F.R.S. West, William, Esq., F.R.S. (deceased). Western, Thomas Burch, Esq. . Wharncliffe, John Stuart,Lord,F.R.S.(dec*). Wheatstone, Professor Charles, ¥.R.8. Whewell, Rev. William, D.D., F.R.S., Master of Trinity College, Cambridge. Williams, Prof. Charles J. B., M.D., F.R.8. Willis, Rey. Professor Robert, M.A., F.R.S. Wills, William, Esq., F.G.8. (deceased). Wilson, Prof. W. P. Winchester, John, Marquis of. Woolleombe, Henry, Bsq., F.8.A. (deceased) Wrottesley, John, Lord, M.A., Pres. B.S. Yarborough, The Earl of, D.C.L. Yarrell, William, Esq., F.L.S. (deceased). Yates, James, Esq., M.A., F.RS. Yates, J. B., Esq., F.S.A., F.R.G.S. dee"). OFFICERS AND COUNCIL, 1859-60. TRUSTEES (PERMANENT). Str Ropericx I. Murcuison,G.C.St.S.,F.R.S. Major-General Epwarp SABINE, Joun Taytor, Esq., F.R.S. R.A, D.C.L., Treas, & V.P.R.S. PRESIDENT. HIS ROYAL HIGHNESS THE PRINCE CONSORT. VICE-PRESIDENTS. The Duxe or RicumonpD, K.G., F.R.S., Pre- sident of the Royal Agricultural Society. The Eart or Azperpren, LL.D., K.G., K.T., F.R.S. The Lorp Provost of the City of Aberdeen. Sir Joun F. W. Herscuet, Bart., D.C.L., M.A., F.R.S. Sir Davin Brewster, K.H., D.C.L., F.R.S., Principal of the University of Edinburgh. Sir R. I. Murcuison,G.C.St.S.,D.C.L.,F.R.S., and Director-General of the Geological Sur- vey of the United Kingdom. The Rev. W. V. Harcourt, M.A., F.R.S. The Rey. T. R. Roprnson, D.D., F.R.S., Di- rector of the Armagh Observatory, Armagh. A. Tuomson, Esq., LL.D., F.R.S., Convener ’ of the County of Aberdeen. PRESIDENT ELECT. THE LORD WROTTESLEY, M.A., V.P.R.S., F.R.A.S. VICE-PRESIDENTS ELECT. The Barz or Dersy, P.C., D.C.L., Chan- Cuartes G. B. Davuseny, LL.D., M.D., cellor of the University of Oxford. The Rey. F. Jeunes, D.D., Vice-Chancellor of the University of Oxford. The Duke or MartsoroveH, D.C.L. The Eart or Rossz, K.P., M.A., F.R.S., F.R.A.S. The Lorp Bisuor or Oxrorp, F.R.S. The Very Rev. H. G. Lippett, D.D., Dean of Christ Church, Oxford. E.R.S., F.L.S., F.G.8., Professor of Botany in the University of Oxford. Henry W. Actanp, M.D., D.C.L., F.R.S., Regius Professor of Medicine in the Uni- versity of Oxford. Wiii1am F. Donkin, Esq., M.A., F.R.S., Savilian Professor of Astronomy in the University of Oxford. LOCAL SECRETARIES FOR THE MEETING AT OXFORD. Grorce RotiEston, M.D., Lee’s Reader in Anatomy in the University of Oxford. H. J. S. Smira, Esq., M.A., Balliol College, Oxford. Grorce Grirritn, Esq., M.A., Jesus College, Oxford. LOCAL TREASURERS FOR THE MEETING AT OXFORD. The Rey. Ricuarp GreswELL, M.A., F.R.S., Worcester College, Oxford. The Rev. Joun Grirrirus, M.A., Wadham College, Oxford. ORDINARY MEMBERS OF THE COUNCIL. BABINGTON, E.R.S. Bropige, Sir Bensamin C., Bart., D.C.L., Pres. R.S. Dea Rug, Warren, Ph.D., F.R.S. EGerton, Sir Poitir pe M. Grey, Bart., F.R.S. C. C., M.A, F.R.S. Gassior, Joun P., F.R.S. Grove, Witui1AMR., F.R.S. Horner, LEONARD, F.R.S. Hurron, Rozert, F.G.S. LyeEzt, Sir C., D.C.L., F.R.S. Swarpry,Professor, Sec. R.S. Mitter, Prof. W. A., M.D., Price, Rey. Professor, M.A., F.R,S. Renniz, Georce, F.R.S. RusseE 1, J. 8., F.R.S. Sykes, Colonel W. H., M.P., F.R.S. Porttocx,General,R.E.,F.R.S. Tire, WittrAM, M.P., F.R.5S. Powe tt, Rev. Prof., M.A., F.R.S. Wesster, THomas, F.R.S. Yates, JAmus, M.A,, F.R.S. Farrpairn, WILLIAM,E.R.S. FirzRoy,RearAdmiral,F.R.S. EX-OFFICIO MEMBERS OF THE COUNCIL. The President and President Elect, the Vice-Presidents and Vice-Presidents Elect, the Ge- neral and Assistant-General Secretaries, the General Treasurer, the Trustees, and the Presi- dents of former years, viz.—Rev. Professor Sedgwick. Sir Thomas M. Brisbane, Bart. The Marquis of Lansdowne. TheDuke ofDevonshire. Rey. W.V.Harcourt. The Marquis of Bread- albane. Rev. W. Whewell, D.D. The Earl of Rosse. Sir John F. W. Herschel, Bart. Sir Roderick I. Murchison. The Rey. T. R. Robinson, D.D. Sir David Brewster. G. B. Airy, Esq., the Astronomer Royal. General Sabine. William Hopkins, Esq., LL.D. The Earl of Harrowby. The Duke of Argyll. Professor Daubeny, M.D. The Rev. H. Lloyd, D.D. Richard Owen, M.D., D.C.L. GENERAL SECRETARY. The Rey. Roperr Waker, M.A., F.R.S., Reader in Experimental Philosophy in the Uni- versity of Oxford; Culham Vicarage, Abingdon. ASSISTANT GENERAL SECRETARY. Joun Puitiirs, Esq., M.A., LL.D., F.R.S., Pres.G.S., Reader in Geology in the University of Oxford ; Museum House, Oxford. GENERAL TREASURER. Joun Tayzor, Esq., F.R.S., 6 Queen Street Place, Upper Thames Street, London. LOCAL TREASURERS. Robert P. Greg, Esq., I.G.S., Manchester. © John Gwyn Jeffreys, Esq., F.R.S., Swansea. J. B. Alexander, Esq., Ipswich. Robert Patterson, Esq., M.R.I.A., Belfast. Edmund Smith, Esq., Hull. Richard Beamish, Esq., F.R.S., Cheltenham. John Metcalfe Smith, Esq., Leeds. John Angus, Esq., Aberdeen. AUDITORS. Dr. Norton Shaw. William Gray, Esq., F.G.S., Yors. C.C. Babington, Esq.,M.A., F.R.S., Cambridge. William Brand, Esq., Edinburgh. John H. Orpen, LL.D., Dudlin. William Sanders, Esq., F.G.S., Bristol. Robert M‘Andrew, Esq,., F.R.S., Liverpool. W.R. Wills, Esq., Birmingham. Professor Ramsay, M.A., Glasgow. Robert Hutton, Esq. James Yates, Esq. OFFICERS OF SECTIONAL COMMITTEES. XXVil OFFICERS OF SECTIONAL COMMITTEES PRESENT AT THE ABERDEEN MEETING. SECTION A.—-MATHEMATICS AND PHYSICS. President.—The Earl of Rosse, M.A., K.P., F.R.S,, M.R.I.A. Vice-Presidents.—G. B. Airy, M.A., D.C.L., Astronomer Royal, F.R.S. L. & E., M.R.1.A. ;_Sir David Brewster, K.H., F.R.S. L.& E,, M.R.I.A.; Sir W. R. Hamil- ton, LL.D., Astronomer Royal of Ireland, M.R.I.A.; Professor William Thomson, M.A., LL.D., F.R.S.; Rev. T. R. Robinson, D.D., F.R.S.; Rey. H. Lloyd, D.D., LL.D., F.R.S., M.R.1.A.; T. Maclear, F.R.S., F.R.A.S., Astronomer Royal at the Cape of Good Hope. Secretaries.—Professor Stevelly, LL.D.; H.J.S. Smith, M.A.; J. Pope Hen- nessy, M.P. ; Professor Maxwell, F.R.S.E. SECTION B.—CHEMISTRY AND MINERALOGY, INCLUDING THEIR APPLICATIONS TO AGRICULTURE AND THE ARTS. President.—Professor Lyon Playfair, C.B., Ph.D., F.R.S., F.C.S. Vice-Presidents.—R. Christison, M.D., F.R.S.E.; Professor Daubeny, M.D., LL.D., F.R.S., F.C.S. ; W. De la Rue, Ph.D., F.R.S., F.C.S, ; Professor Faraday, D.C.L., F.R.S., F.C.S.; Rev. W. Vernon Harcourt, M.A., F.R.S., F.C.S.; T. Gra- ham, M.A., D.C.L., Master of the Mint, F.R.S., F.C.S.; Professor A. W. William- son, Ph.D., F.R.S., F.C.S. Secretaries.—J. S. Brazier, F.C.S.; J. H. Gladstone, Ph.D., F.R.S., F.C.S.; G. D. Liveing, M.A., F.C.S.; W. Odling, Ph.D., F.R.S:, F.C.S. SECTION C.—GEOLOGY. President.—Sir Charles Lyell, M.A., LL.D., D.C.L., F.R.S., F.G.S. Vice-Presidents.—Sir R. I. Murchison, G.C.St.S., D.C.L., F.R.S., F.G.S.; Sir Richard Griffith, Bart., LL.D., F.R.S., M.R.LA., F.G.S.; Professor Sedgwick, M.A., F.R.S., F.G.S.; William Hopkins, M.A,, LL.D., F.R.S., F.G.S.; Major- General Portlock, R.E., LL.D., F.R.S., F.G.S.; Professor A. C. Ramsay, F.R.S., F.G.S.; Professor H. D. Rogers, LL.D., F.R.S., F.G.S. Secretaries.—Professor Harkness, F.R.S., F.G.S.; H.C. Sorby, F.R.S., F.G.S. ; Rev. J. Longmuir, A.M., LL.D. SECTION D.—ZOOLOGY AND BOTANY, INCLUDING PHYSIOLOGY. President.—Sir William Jardine, Bart., F.R.S.E., F.L.S. Vice- Presidents.— Professor Allman, M.D., F.R.S. L.& E., M.R.LA.; C. C. Ba- bington, M.A., F.R.S., F.L.S.; Professor Balfour, M.D., F.R.S., F.L.S. ; Professor Daubeny, M.D., LL.D., F.R.S., F.L.S.; Professor Huxley, F.R.S., F.L.S; Pro- fessor Owen, M.D., LL.D., D.C.L., F.R.S., F.L.S. Secretaries.—E. Lankester, M.D., LL.D., F.R.S., F.L.S. ; Professor Dickie, M.D. ; G, Ogilvie, M.D. SUB-SECTION D.—PHYSIOLOGICAL SCIENCE. President.—Professor Sharpey, M.D., Sec.R.S. Vice-Presidents—Henry W. D. Acland, M.D., D,C.L., F.R.S.; Sir Benjamin C, Brodie, Bart., D.C.L., Pres.R.S.; Professor Christison, M.D., F.R.S.E.; Sir James Clark, Bart., M.D., F.R.S.; Professor Syme, F.R.S.E,; Professor Allen Thomson, M.D., F.R.S., L. & E. Secretaries.—Professor Redfern, M.D, ; Professor Bennett, M.D., F.R.S.E. SECTION E.—GEOGRAPHY AND ETHNOLOGY, President.—Rear-Admiral Sir James Clark Ross, D.C.L., F.R.S. Vice-Presidents.—Sir R. I. Murchison, G.C.St.S., D.C.L., V.P.R.S., F.R.G.S. ; Colonel Sir Henry James, R.E., F.R.S., F.R.G.S; Rear-Admiral FitzRoy, F.R.S. F.R.G.S; Sir John Bowring, F.R.S., F.R.G.S.; John Crawfurd, F.R.S., F.R.G.S. Very Rev. Principal Campbell, D.D. ; Sir James Clark, Bart., M.D., F.R.S., F.R.G.S. in chats as Norton Shaw, Sec.R.G.S.; Richard Cull, F.R.G.S,; Professor eddes, ve XXVlll REPORT—1859. SECTION F,—ECONOMIC SCIENCE AND STATISTICS. President.—Colonel Sykes, M.P., F.R.S. Vice-Presidents.—Lord Monteagle, M.A., F.R.S.; W. Tite, M.P., F.R.S,; Alex- ander Thomson of Banchory; Principal the Rev. D. Dewar, D.D., LL.D. Secretaries—John Strang, LL.D.; Edmund Macrory, M.A.; H. Ambrose Smith ; Professor Cairnes. SECTION G.—MECHANICAL SCIENCE. President. —The Rev. Professor Willis, M.A.,I°.R.S., Jacksonian Professor, Cam- bridge. Vice-Presidents:x—J. F. Bateman, C.E.; Admiral Drinkwater Bethune, C.B., F.R.G.S.; W. Fairbairn, C.E., F.R.S.; Vice-Admiral Moorsom; The Rev. Canon Moseley, M.A., F.R.S.; G. Rennie, F.R.S.; T. Webster, F,R.S. Secretaries.—R. Abernethy; P. Le Neve Foster, M.A.; H. Wright. CORRESPONDING MEMBERS. Professor Agassiz, Cambridge, Massa- chusetts. M. Babinet, Paris. Dr. A. D. Bache, Washington. Professor Bolzani, Kazan. Barth, Dr. Mr. P. G. Bond, Cambridge, U.S. M. Boutigny (d’Evreux). - Professor Braschmann, Moscow. Chevalier Bunsen, Heidelberg. Dr. Ferdinand Cohn, Breslau. M. Antoine d’Abbadie. M. De la Rive, Geneva. Professor Dove, Berlin. Professor Dumas, Paris. Dr. J. Milne-Edwards, Paris. Professor Ehrenberg, Berlin. Dr. Eisenlohr, Carlsruhe. Professor Encke, Berlin. Dr. A. Erman, Berlin. Professor Esmark, Christiania. Professor G. Forchhammer, Copenhagen. M. Léon Foucault, Paris. Prof. E. Fremy, Paris. M. Frisiani, Milan. Professor Asa Gray, Cambridge, U.S. Professor Henry, Washington, U.S. M. Jacobi, St. Petersburg. Prof. A. Kolliker, Wurzburg, Prof. De Koninck, Liege. Professor Kreil, Vienna. Dr. A. Kupffer, St. Petersburg. Dr. Lamont, Munich. Prof. F. Lanza, M. Le Verrier, Paris. Baron von Liebig, Munich. Professor Loomis, New York. Professor Gustav Magnus, Berlin. Professor Matteucci, Pisa. Professor von Middendorff, St. Petersburg. M. Abbé Moigno, Paris. ' Professor Nilsson, Sweden. Dr. N. Nordensciold, Fin/and. M. E. Peligot, Paris. Viscenza Pisani, Florence. | Gustave Plaar, Strasburg. Chevalier Plana, Turin. Professor Pliicker, Bonn. M. Constant Prévost, Paris. M. Quetelet, Brussels. Prof. Retzius, Stockholm. Professor H. D. Rogers, Boston, U.S. Professor H. Rose, Berlin. Herman Schlagintweit, Berlin. Robert Schlagintweit, Berlin. Dr. Siljestrom, Stockholm. M. Struveé,-Pulkowa. Dr. Svanberg, Stockholm. M. Pierre Tchihatchef. Dr. Van der Hoeven, Leyden. Baron Sartorius von Waltershausen, Gottingen. Professor Wartmann, Geneva, Report of the Council of the British Association, presented to the General Committee at Aberdeen, September 14, 1859. 1. With reference to the subjects referred to the Council by the General Committee at Leeds, the Council have to report as follows :— a, The General Committee passed the following resolutions, viz.— “ That it is highly desirable that a series of Magnetical and Meteorolo- gical Observations, on the same plan as those which have been already carried on in the Colonial Observatories for that purpose, under the direction REPORT OF THE COUNCIL. XX1X of Her Majesty’s Board of Ordnance, be obtained, to extend over a period of not more than five years, at the following stations :— 1. Vancouver Island. 2. Newfoundland. 3. The Falkland Isles. 4, Pekin, or some near adjacent station. «That an application be made to Her Majesty’s Government to obtain the establishment of Observatories at these stations for the above-mentioned term, on a personal and material footing, and under the same superintend- ence as in the Observatories (now discontinued) at Toronto, St. Helena, and Van Diemen’s Land. “ That the observations at the Observatories now recommended should be comparable with, and in continuation of, those made at the last-named Observatories, including four days of term-observations annually. “ That provision be also requested at the hands of Her Majesty’s Govern- ment, for the execution, within the period embraced by the observations, of magnetic surveys in the districts immediately adjacent to those stations, viz. of the whole of Vancouver's Island and the shores of the Strait sepa- rating it from the main land,—of the Falkland Isles,—and of the immediate neighbourhood of the Chinese Observatory (if practicable) wherever situ- ated,—on the plan of the surveys already executed. in the British posses- sions in North America and in the Indian Arehipelago. «“ That a sum of £350 per annum, during the continuance of the obser- vations, be recommended to be placed by Government at the disposal of the General Superintendent, for the purpose of procuring a special and scientific verification and exact correspondence of the magnetical and me- teorological instruments, both of those which shall be furnished to the several Observatories, and of those which, during the continuance of the observations for the period in question, shall be brought into comparison with them, either at Foreign or Colonial Stations. ¢ That the printing of the observations 77 ewtenso be discontinued, but that provision be made for their printing in abstract, with discussion ; but that the Term-Observations, and those to be made on the occurrence of Magnetic Storms, be still printed 2 eatenso; and that the registry of the observations be made in triplicate, one copy to be preserved in the oftice of the General Superintendent, one to be presented to the Royal Society, and one to the Royal Observatory at Greenwich, for conservation and future reference. ‘«<’That measures be adopted for taking advantage of whatever disposi- tion may exist on the part of our Colonial Governments to establish Obser- vatories of the same kind, or otherwise to cooperate with the proposed system of observation. “That in placing these Resolutions and the Report of the Committee _ before the President and Council of the Royal Society, the continued co- operation of that Society be requested in whatever ulterior measures may be requisite. “That the President of the British Association be requested to act in conjunction with the President of the Royal Society, and with the Members of the two Committees, in any steps which appear necessary for the accomplishment of the objects above stated. “ That an early communication be made of this procedure to His Royal Highness The Prince Consort, the President Elect of the British Associa- tion for the ensuing year.” D. 6.6.4 REPORT—1859. At a Meeting of the Council on December 17, 1858, the President stated that communications had been made on the subject of these Resolutions to the President and Council of the Royal Society, and to His Royal Highness The Prince Consort, the President Elect of the British Association for the ensuing year. He then presented the following letters, which were ordered to be entered on the Minutes :— “ Windsor Castle, December 1, 1858. “Dear Srr,—I have been commanded by His Royal Highness The Prince Consort to acknowledge with thanks the receipt of the series of resolutions adopted by the Council of the British Association, relative to the extension of the field of Magnetical and Meteorological Observations, “ His Royal Highness would be glad to be informed whether it is expected from him, as President Elect of the Association, that he should take any steps with reference to the object the Council has in view, and if so, what they should be. “T have also to thank you, by His Royal Highness's desire, for the copy of your Address, *T have the honour to be, dear Sir, * Yours very faithfully, “C, Grey.” “ Burlington House, December 9, 1858. “Dear Sir,—In reference to the inquiry manifesting the interest which His Royal Highness The Prince Consort takes in the subject of the Resolu- tions of the Council of the British Association lately submitted to him, we are aware that we ought not to solicit any personal or direct action of His Royal Highness in the matter; but, having laid before him the nature and reasons of the case, and His Royal Highness being fully aware of its important scientific bearings, any expression of His Royal Highness which the joint Committees may be permitted to cite in their further communi- cations with Her Majesty’s Government or with Foreign Powers, Academies, or constituted scientific authorities would, they feel confident, possess very great influence, and be productive of the most beneficial effects, (Signed) “B. C. Broniz, P.R.S. “ RicHARD Owen, Pres. Brit. Assoc,’ “ To Major-Gen. Hon. C. Grey.” “ Osborne, 11 December, 1858. “My pEAR Prorressor OwEN,—I have to acknowledge the receipt of the Copy of Resolutions adopted at a Meeting of the British Association, with respect to the measures to be adopted for the further prosecution of your Magnetical and Meteorological Experiments, which I received before leaving Windsor; and I have now seen the letter which, in conjunction with Sir B, Brodie, you have addressed to General Grey, in answer to the inquiry respect- ing the above-mentioned resolutions, which he made by my direction. “I need hardly repeat the assurance of the deep interest which I take in the subject of your inquiries, or of my sense of the importance to science of the further prosecution of the observations which have been so far conducted under the auspices of the two Societies, the interruption of which, at the very moment when there is so much reason to hope for their successful com- pletion, would be a source of deep regret. Any assistance in my power to afford, I shail at all times be most happy to render. If, therefore, you think that in your future communications with Government, or with Foreign Powers, learned Institutions, &c., it will tend in any way to facilitate your labours, or to remove difficulties, to cite my opinion, you have my full per- REPORT OF THE COUNCIL. XXX1 mission to state, in the strongest manner, the conviction I entertain of the importance of being enabled to establish those new points of observation in different parts of the world, and to execute those magnetic surveys to which the Resolutions allude, « Wishing you most heartily every success in the further development of this most interesting subject, “T remain, yours faithfully, (Signed) ‘ ALBERT,” It was also stated by the President that a letter had been received from the Treasury, in reply to a communication enclosing the Resolutions above given by the President of the Royal Society and the President of the British Association, from which it appeared that the Lords Commissioners of the Treasury were desirous of postponing for a year the consideration of the subject. On this it was resolved by the Council— That the President be requested to make a further communication to the Treasury, and to suggest reasons which may induce the Lords of the Trea- sury to enter on the consideration of the subject at an earlier period. In compliance with this request, the President had an interview with Sir Charles Trevelyan at the Treasury, December 18th, and having read to him the letter from the Prince Consort, expressive of His Royal Highness’s deep interest in the proposed Magnetical Observations, received from Sir Charles the expression of his belief, that, if a single station for Magnetical and Meteorological Observations were applied for, intimating Pekin as its locality, by the joint Committee of the Royal Society and British Association, My Lords would be disposed to comply with such application. The President thereupon wrote to the President of the Royal Society, to Major-General Sabine, and Sir John Herschel, and, having received their replies, communicated to Sir Charles Trevelyan that from Major-General Sabine, of which a copy is subjoined, together with the following extract from Sir John Herschel’s letter, dated Collingwood, Dec. 22nd, 1858 :— “ The scientific importance of a five years’ series of Magnetical Observations at Pekin, without Newfoundland or the other stations (Vancouver's and Falkland Islands), would be grievously diminished, and the general scope of the project defeated,” From General Sabine. “ St. Leonards-on-Sea, January Ist, 1859. “Dear OwEn,—I have received your letter of the 27th ult., containing a notice of your communication with Sir Charles Trevelyan, and enclosing copies of letters from Sir John Herschel and Mr. Airy. “There would in no case have been any question of an estimate for the present year, viz. 1859. The instruments even for a single Observatory cannot be ready before Midsummer next ; and those who are to be charged with the observations will require at least some weeks for a full training, before they will be ready to proceed to their destination. Supposing, therefore, but a single Observatory to be authorized, it will come properly into the estimates for 1860, though there may be a small arrear to be included for the latter part of the preceding financial year. “ Before Mr. Welsh left Kew in November last, he gave Mr. Adie the specifications for the differential instruments (for the three elements) which it is our intention to propose as most suitable for a Colonial Observatory ; and Mr, Adie undertook to have them completed and ready by Midsummer XXX1i REPORT—1859. next. They are to serve either for eye-observation or for continuous photo- graphic record, or for both, occasional eye-observations being desirable in any case. The space which it is proposed they should occupy, is 12 feet by 6; and their relative position, as well as that of all their parts, will be determined by their being fixed into a slate floor or basement, capable of being separated into portions for more easy conveyance to a Colony, but designed, when there, to be put together and cemented into one solid floor, which must rest on asecure foundation. The protection from the weather which the instru- ments will require, will be (in the Colony) a double wall either of logs or of stone, having space between the outer and inner wall, and a similarly double ceiling. When the instruments are set up in the space near the Observatory at Kew, a simple boarding will suffice in lieu of double walls and ceiling, as the equalization of temperature is of no moment when the purpose is simply to give instruction in the use of the instruments. The instruments for absolute determinations will require a small separate building, in which the absence of iron will be the only requisite, the variations of temperature not being of the same moment in their case. “Tt is proposed that the description and the principal instructions for the use of these differential instruments should form an appendix to Mr. Welsh’s report on the self-recording Magnetic Apparatus at Kew, which apparatus has now been in steady work for some months. Mr. Welsh’s report is to be pre- sented to the Aberdeen Meeting, and will be printed forthwith. “ Viewing the importance of ééme, I took on myself in October last the responsibility of directing Mr. Adie to proceed in the construction of these instruments. On the understanding conveyed by your letter that one Observa- tory at least will be sanctioned, and supposing that the instruments shall be found to answer their purpose satisfactorily, I shall be relieved from the pecu- niary responsibility so undertaken ; but I hadat anyrate very little apprehension on this account; forthe improvement of standard Magnetical and Meteorolo- gical instruments has been so thoroughly recognized as a proper ground of ap- plication to the Government Grant Committee, that I should not have hesi- tated to ask for aid from that quarter, if needed. It was probable, moreover, that had the instruments not been required by our own Government, a ready sale might have been found for them to some projected Colonial or Foreign Establishment. “If Mr. Adie keeps his time, the Observatory will be ready for inspection and for practice early in the next summer, when it is hoped that those who are competent to judge of the suitability of the instruments will examine them, and will offer such suggestions of improvement as may be applicable, either in the present ease or in Observatories for the same purpose which may be required hereafter. “Captain Blakiston of the Royal Artillery, to whom I had written to offer the best offices in my power towards his appointment to the charge of the Vancouver Island Observatory (supposing always that His Royal Highness the Commander-in-Chief should be favourably disposed towards the employ- ment of an Artillery detachment as the ‘personnel’ of the Observatory ), has replied by stating his readiness to accept the charge, and to enter at once, on his return from his present employment, on the training required for the photographic work. He is the Magnetieai Observer of Mr. Palliser’s Survey Expedition on the east side of the Rocky Mountains. The Expedi-. tion is ordered to return to England in the next summer; consequently at the close of the summer Capt. Blakiston will be available for this duty. I may add, in evidence of the zealous interest taken by this officer in Magnetic researches, that I have very recently received from him five months of hourly REPORT OF THE COUNCIL. XSXL observation of the Declinometer, made in the winter of last year at Fort Carlton on the Saskatchewan, in which he has himself taken the principal part. I should propose to recommend as his Assistant, either at Vancouver Island or at Pekin, Lieut. Maunsell of the Royal Artillery, who, being an Undergraduate at Trinity College, Dublin, obtained his Commission two years since by taking a high place in the competitive examination, and is now about to obtain leave of absence to take his degree at Trinity College. My personal knowledge of this Officer is but slight, but it leads me to regard him as a person of much promise in scientific respects. He has placed his services (always presuming the approval of His Royal Highness the Commander-in- Chief) at my disposal for any part of the globe at which Magnetic Obser- vations may be required. At remote stations, such as Vancouver Island or: Pekin, a second officer is highly expedient in the event of casualties, as well as for the Survey connected with the Observatory, for which the detachment will be well provided with instruments, whether such Survey be to be pro- secuted by sea or land. The Assistants at Kew, who are carrying on the work of the regular photographic Magnetic Observatory there, are fully com- petent, and would be quite ready to give the Officers and Non-Commissioned Officers the necessary instructions in manipulation, &c.; and I know of no reason why the ‘matériel’ and ‘personnel’ of an Observatory destined either for Vancouver Island or Pekin, should not be ready to proceed to their destination in the autumn of 1859. “ The charge which would subsequently devolve upon me, would be simply that of receiving and properly preserving the monthly returns containing duplicates of the photographie traces, and the tabulated abstracts prepared from them corresponding to every hour or every half-hour as might be deemed preferable. The arrangements which Mr. Welsh has prepared for tabulating from the traces, seem to leave nothing to be desired. There is nothing onerous in this charge, which would require only suitable presses for the arrangement of the papers, and the superintendence of a Non-Commissioned Officer acting as a Clerk under my directions. The quarterly or half-yearly applications from the Observatory for supplies of chemicals, &c., would be met through the instrumentality of the Director of the Kew Observatory, who is constantly requiring supplies of the same nature for the apparatus there. When the tabulated abstracts of the first year had been received at Woolwich complete, they might be passed through the same process of analysis for the determination of the laws of the disturbances which has been exemplified in the Observations of the Colonial Observatories. This has been worked into such a thorough system, that it would proceed with only the most general superintendence on my part, and would also, I consider, occasion no serious interruption in what would at that time be the regular and staple business of the Office, @. e. the reduction and coordination of the Naval Magnetic Surveys. The second and third years’ abstracts might be simi- larly treated as they arrived; and Iam inclined to think that I may, without too much presumption, look forward, please God, to the probability of my being myself able to give such a provisional report of the results as might be justified by the first three years of observation. I might also look forward, but of course with less confidence, to being able to derive the laws of the secular changes of the three elements from the absolute determinations at the expira- tion of the six years (if then alive and in ¢éolerable health), which, from the long experience which I have had in such investigations, would be far easier to me than it could well be to any other person. But whatever might be the measure of my own competency in future years, the photographic traces of the tabulated abstracts, carefully preserved and arranged, would be transferred, 1859. c XXXIV REPORT—1859. at the close of the series, to some place of proper deposit, where they would be available for those who, in years to come, will carry on the magnetic in- vestigations of which the value has now begun to be appreciated. “The comparison of simultaneous photographie records at different Obser- vatories will constitute a distinct work, from which, very possibly, a far more complete knowledge of the laws of the disturbances may be expected; and for this the materials would be preserved and arranged: but the execution must be looked for from other hands than mine. If, as may be expected, the establishment of self-recording apparatus at Pekin or Vancouver Island be followed by the establishment of similar instruments in other places, an in- terchange of photographic traces might be desirable, and could be readily effected by little more than clerk’s work. ; “T do not encumber this already long letter with remarks on the com- parative scientific value of Vancouver Island and Pekin as Magnetic Sta- tions; both are highly important; but this much is certain, that whatever might be the value of either, that value would be greatly enhanced—far more than doubled—by there being a simultaneous and continuous record at both Stations. It has been remarked [by Sir Charles Trevelyan] that there are ‘other than scientific reasons’ which would give a preference to Pekin. This remark might indeed be made in other countries ; but the establishment at Pekin would be unanswerably justified by the sczentifie importance of having two Stations in nearly the same latitude on the opposite shores of the Pacific. “« By recent letters from the United States, I learn that the steps taken in this country in regard to the continuance of Magnetical investigations, have already produced a corresponding feeling in that country, and a desire that one Observatory at least, on a similar plan to that which should be adopted in this country, should be established somewhere on the Eastern Sea-bord of the United States. This would in a considerable measure fulfil the objects contemplated in the suggestion of Newfoundland as a Magnetic Station. The letters of Mr. Kingston (by which it appears that, when writing to Sir John Herschel on the 26th of June 1858, 1 was not thoroughly in- formed of the full purpose of the Canadian Legislature to maintain the Toronto Observatory in fullest. efficiency) may give reason to expect that, if the instruments for a continuous record shall be approved, the present differential instruments at Toronto, which are only adapted for eye-obser- vation, may be replaced by the contemplated ones, which are capable of both. (Signed) ** EDWARD SABINE.” “ Professor Owen, President of the British Association.” At a Meeting of the Council held this morning (September 14, 1859) at Aberdeen, the following Report was received from Sir John Herschel, Chair- man of the joint Committees of the Royal Society and British Association, appointed to endeavour to procure the continuance of Magnetical researches, by which the General Committee will be fully informed of the proceedings in this matter up to the present time, and will be able to judge what further steps it may be desirable to take. The Committee of the British Association appointed to cooperate with a Committee of the Royal Society, to endeavour to procure the continuance of the Magnetic Observations, &c., have to report progress as follows :— Immediately on the breaking up of the meeting at Leeds, the recom- mendation adopted by the. General Committee of the Association, to the effect (“That an early communication be made of the procedure taken on REPORT OF THE COUNCIL. XXXV that occasion to His Royal Highness The Prince Consort, the President Elect of the British Association for the ensuing year”] was duly acted upon. The particulars of this communication, together with His Royal Highness’s most gracious letter to the then President of the Association, expressive of his deep interest in the subject, and his readiness to afford every assistance in his power in facilitating the labours of that body and of the Royal Society towards the accomplishment of the object in view, have been communicated to the Council, and are recorded in the Minutes of its meeting held on Dee, 17th, 1858. The Resolutions agreed to and the Report of the Committee were also, in pursuance of the directions of the General Committee, placed before the President and Council of the Royal Society, with a request for their further cooperation,—which, it is almost needless to state, has been most cordially received and acted on. In further compliance with the recommendations adopted by the General Committee, a communication was made of the Resolutions on the subject, by the Presidents of the Royal Society and the British Association, to the Lords Commissioners of the Treasury, as stated in the Minutes of the meeting of Council above mentioned, the immediate result being an expression of their Lordships’ wish for a postponement of the subject for the present year. But on the President of the Association, pursuant to the request of the Council, having requested an interview with Sir C. Trevelyan, and reading to him the letter from the Prince Consort above mentioned, it was intimated that an application for a single station at Pekin, for Magnetic and Meteorological Observations, emanating from the joint Committee of the Royal Society and British Association, would find their Lordships disposed to comply with it. The further correspondence to which this intimation gave rise (including a letter from General Sabine to the President of the British Association, ex- planatory of the circumstances which would at all events create delays in the preparations for any active steps until the summer of the present year, arising from the time requisite to prepare the necessary instruments and other considerations) stands also recorded in the form of an addendum to the Minutes of Council of the above-mentioned date, and need not therefore be here repeated. Since these communications, the subject, so far as the action of the Government is concerned, remains in abeyance; and it will be for the decision of the meeting of this Association now pending, whether any and what step should be further taken to recall its attention to the subject. Meanwhile, for the present no time has been hitherto lost in the preparation of instruments, so far as would be justifiable by the prospect of the esta- blishment of at least one Observatory. General Sabine reports, in a letter to Sir J. Herschel, dated August 29th, 1859, to the following effect :— “My pear Sir,—I went to Kew this morning, and I had the gratifica- tion of seeing the Self-recording Magnetic instruments prepared for the first of the proposed new observatories, in the house which had been erected for their examination and for the instruction of the parties who are to use them. Everything may now be said to be ready for the reception and instruction of such parties by the Assistants of the Kew Observatory. The temporary house is detached from the Observatory, so that parties under instruction will not interfere with the regular work of the Observatory instruments. Gas is introduced into the temporary house; and on consulting Mr. Stewart, I found him of opinion that about six weeks might fully suffice for the in- struction of the parties both in the self-recording and in the absolute instru- ments (the latter are also ready, and are used in a separate house). At the c2 XXXVI REPORT—1859. end of the six weeks, therefore, the party might be ready to embark, taking their instruments away with them; and a second set of instruments might then take their place for the instruction of a party for a second Observatory. All the arrangements contemplated in my letter* to Professor Owen of January Ist, 1859, are complete, so far as the Kew Observatory, Mr. Adie, and myself are concerned; and we are ready to receive and send away the first party to their destination, whether it might be British Columbia or Shanghai, as soon as the Government pleases.” (Signed) *« EDWARD SABINE.” The interval elapsed since the last meeting of the Association has not been wanting in affording proofs of the high interest taken in the subject of these observations in other countries. Foremost in expressions of willing cooperation are the leaders of public opinion on such subjects in the United States. By a communication from Dr. Bache (Superintendent of the United States Coast Survey) to General Sabine, dated June |, it appears that he is ready to enter con amore into our plans, and that he has his instruments all ready at the Joint Smithsonian and Coast Survey Magnetic Observatory at Washington, and desires only to be informed what course of action shall be here determined on, to afford his ready and powerful cooperation. And by a subsequent communication of the 12th ultimo, he further reports the readiness of President Barnard, of the University of Oxford, Mississippi, to undertake, or cause to be undertaken, a series of concerted observations, provided a formal request (of course duly authorized) from General Sabine be made to that institution to such effect, such a report being necessary to obtain the requisite appropriation of funds from the Board of Trustees. The officers also of the American Asscciation for the Advancement of Science have, we understand, been instructed by that body in their meeting at Springfield, to express to the officers of the British Association their in- terest in these magnetic proceedings. Senhor Da Silva, successor to Senhor Pegado in the direction of the Meteorological Observatory at Lisbon, has expressed his wish to join in the system of magnetic observation to be undertaken in England, an object which he considers might be accomplished provided the British Government would interest itself with the Portuguese in favour of the undertaking, and suggesting that in that event a Portuguese officer might be instructed at Kew in the use of the instruments. The project for the establishment of a Magnetic Observatory on the Eastern Sea-bord of the United States, and the determination of the Cana- dian Legislature to maintain the Toronto Observatory in full efficiency, are noticed in Colonel Sabine’s letter already referred to; and in the event of a British establishment at Vancouver’s Island being procured in addition to Shanghai or Pekin, would complete, in conjunction with the existing Russian Observatories, and with one which might very possibly be established by the University of Kasan in lat. 55°45’ N., under the able direction of Pro- fessor Bolzani (who has expressed his desire to procure self-recording mag- netic instruments similar to those of Kew, and to adopt the proposed system of observations), a chain of stations in considerable north latitude, which would surround the Pole, and afford a connected series of most valuable observations. ; Though not in immediate connexion with the direct object of this Report, your Committee cannot refuse themselves the mention, as matters of Magnetic progress since the last meeting of the Association, of the completion of Mr. * This is the letter above alluded to as forming part of the Minutes of Council of Decem- er 17, 1858. REPORT OF THE COUNCIL. “XXXVii Welsh’s Magnetic Survey of Scotland, as having led to important conclusions as to the nature of the changes which have taken place in the magnetic system of the British Isles since 1837,—changes corroborated by a series of determinations at several stations along the South-western and Southern coasts of England, obtained by General Sabine himself in the course of the current year, since the re-establishment of his health has permitted his invalu- able services to’ become once more available to science. In concluding this Report, your Committee cannot but observe that all the reasons which weighed with them in recommending, jointly with the Com- mittee appointed by the Royal Society, the Resolutions adopted by the General Committee of the British Association at their meeting of last year, for the establishment of Observatories for an additional period of five years at the stations named in their last Report, appear to them to remain in full force; and that even supposing the idea of a station on the Falkland Isles, and even Newfoundland, to be relinquished, they would continue to urge, as fitting objects for recommendation to Government, those of Vancouver's Island and Shanghai. While nothing has occurred to weaken the general reasons adduced in that Report, they appear to have, in one respect, gained some degree of additional weight from the reappearance, during the present year, of the Solar Spots in great abundance, accompanied with exhibitions of auroral phenomena, and of an unusually hot and dry season—all in conformity with the law of period- icity alluded to in it as connecting, in some at present hidden and problematic manner, these phenomena with the magnetic disturbances. (For the joint Committees) J. F. W. Herscuet. Postscript—The following Memorandum, drawn up and communicated by General Sabine, containing a synoptic statement of the proceedings taken in respect of Magnetic Surveys at the instance or through the intervention of the British Association, may, in the opinion of the Committee, be very properly appended to this Report. ‘A Memorandum regarding Magnetic Surveys which have originated, or been promoted by the British Association for the Advancement of Science. August 19, 1859. 1. The first occurrence, it is believed, of a survey being undertaken for the express purpose of determining the positions and values of the isomag- netic lines of declination, dip, and force corresponding to a particular epoch over the whole face of a country or state, was the Magnetic Survey of the British Islands, executed in 1834-1838 by a committee of members of the British Association, acting upon an enlarged view of a suggestion brought before the Cambridge Meeting of the Association in 1833. The results of this Survey, in the determination of the isoclinal and isodynamic lines in Great Britain and Ireland corresponding to the epoch of January Ist, 1837, were published in a memoir in the Transactions of the British Association for 1838 ; and in the determination of the isogonic lines, in the Philsophical Transactions for 1849, Part II. 2. At the Newcastle Meeting of the Association in 1838, a resolution was passed recommending to Her Majesty’s Government the equipment ofa Naval Expedition for the purpose of making a Magnetic Survey in the Southern portions of the Atlantic and Pacific Oceans, and particularly in the higher latitudes between the meridians of New Holland and Cape Horn. This re- commendation, communicated to and concurred in by the Royal Society, XXXVIll REPORT— 1859. gave rise to the voyage of Sir James Clark Ross to the Southern and Ant- arctic Regions in the years 1839-1843. The magnetical results, in the de- termination of the isomagnetic lines over a large portion of the southern hemisphere, were published in the Phil. Trans. for 1842, Art. II.; for 1843, Art. X.; and 1844, Art. VII.: and one part yet remains to be completed, comprehending the meridians between Cape Horn and the Cape of Good Hope ; its publication having been deferred in consequence of the more pressing publications of the Colonial Observatories. 3. A proposition for a Magnetic Survey of the British Possessions in North America was brought before the British Association in a Report published in their Transactions for 1837, and having been subsequently submitted to the Committee of Physics of the Royal Society, received in 1841 the recommendation of the Royal Society to Her Majesty’s Government. The Survey, having been authorized by the Treasury, was carried on in con- nexion with the Magnetic Observatory at Toronto in Canada, under the direction of the Superintendent of the Colonial Observatories, by Lieut. (since Colonel) Lefroy, R.A. The results in regard to the isoclinal and isodynamic lines have been published in the Phil. Trans. for 1846, Art. XVII. The declination observations have been reduced and coordinated with similar observations made in the succession of Arctic Voyages between 1818 and 1855, in a memoir, now in preparation, which will include the British Possessions in North America and the countries which have been explored to the north of them. 4, The Survey of Sir James Ross in 1839-1844 having left a portion of the magnetic lines in the southern hemisphere undetermined between the meridians of 0 and 125° E., an application was made in 1844 to Her Majesty’s Government by the Royal Society, to complete this remaining portion under the direction of the Superintendent of the Colonial Observatories. This was accomplished in 1845 by Lieut. (since Captain) T. E. L. Moore, R.N., and Lieut. (since Major) Henry Clerk, R.A., in a vessel hired by the Admiralty for the purpose, and despatched from the Cape of Good Hope. The results of this Survey were published in the Phil. Trans. for 1846, Art. XVIII. 5. At the Cambridge Meeting of the British Association in 1845, a recom- mendation was made to the Court of Directors of the East India Company, that a Magnetic Survey should be made of the Indiau Seas in connexion with the Magnetic Observatory at Singapore. This recommendation was com- municated to and concurred in by the Royal Society. The Survey, having been entrusted to Captain Elliot, of the Madras Engineers, was completed in 1849, and the results were published in a memoir by Captain Elliot in the Phil. Trans. for 1851, Art. XII. 6. A proposition for a Magnetic Survey of British India having been sub- mitted to the British Association, in a Report printed in the Transactions for 1837, a scheme for the execution of such a Survey was submitted to the Court of Directors of the East India Company by Captain Elliot on his com- pletion of the Survey of the Indian Seas; and having been referred to the Royal Society, received their warm approbation. ‘The Court of Directors having approved the scheme suggested by Captain Elliot, that officer pro- ceeded to India in 1852 for the purpose of carrying it into execution, but died shortly after his arrival at Madras, in August 1852, having but just commenced the operations of the Survey. { 7. In April 1853 a letter was addressed to the President of the Royal Society by the Prussian Minister, Chevalier Bunsen, recommending, by desire of His Majesty the King of Prussia, the Messrs. Schlagintweit, well known by their physical researches in the Eastern and Western Alps, as fitting suc- REPORT OF THE COUNCIL: XXXix cessors to Captain Elliot in the Magnetic Survey of India. In transmitting Chevalier Bunsen’s letter to the Court of Directors, the Royal Society took occasion to express their strong opinion of the importance of completing this Survey, and their belief of the competency of the Messrs. Schlagintweit for such employment. These gentlemen, having been appointed accordingly by the Court of Directors, and supplied with the necessary instruments, in the use of which they were specially instructed at the Kew Observatory, sailed for India in 1855, and continued their observations through the years 1856, 1857, and 1858, during which they determined the magnetic elements at 69 stations in British India, including some stations north of the Himalayan chain. These observations have been prepared for publication by the Messrs. Schlagintweit, and the printing of the volume containing them is nearly completed. 8. Twenty years having elapsed since the former Survey of the British Islands (referred to in the first paragraph) was made, the British Association deemed that a sufficient interval had passed to make a repetition of the survey desirable, with a view to the investigation of the effects of the secular change which the magnetic lines are known to undergo. Accordingly, at the Cheltenham Meeting of the Association in 1857, the same gentlemen who had made the Survey of 1837, and who, as it happened, were all living, were requested to undertake a fresh Survey. This has been for the most part accomplished, and the observations in England, Scotland, and Ireland are now undergoing the process of reduction and coordination ; and it is hoped that a part, if not the whole, will be completed in time to be included in the volume of the Transactions of the Association in 1859. EDWARD SABINE. b. The General Committee at Leeds having directed that application be made to the Sardinian Authorities for obtaining additional facilities to scien- tific men for pursuing their researches on the summits of the Alps,— The President was requested to communicate thereupon with the Marquis d’ Azeglio, the Sardinian Minister, and the Council have now the pleasure of communicating the following statement from Professor Owen as the result of that communication :— “TJ wrote to his Excellency, the Marquis d’Azeglio, on the 3rd February ; and on the 4th received an acknowledgement of my letter, with the assurance that the subject of it would be forwarded to the competent authorities at Turin, accompanied by a special recommendation from his Excellency. “On the 17th February, 1 was favoured by a letter from the Marquis d’Azeglio informing me that the Minister of the Interior had been occupied by the preparation of new regulations on the subject of the Guides at Cha- mouni ; and that, in all probability, the new regulations, based upon a prin- ciple of wider liberty of action, would be rigorously enforced at the com- mencement of the summer of 1859; and that he had every reason to believe it would satisfy all the requirements of scientific travellers in the Piedmont- ese Alps. * T communicated this favourable reply to Professor Tyndall, and received the expression of his entire satisfaction in the result of the intervention of the British Association.” 2. The Council has been informed by a letter from Dr. A. D. Bache to the General Secretary, that at the Meeting of the American Association for the Advancement of Science, held at Springfield in August 1859, the officers were instructed to express to the British Association for the Advance- xl REPORT—1859. ment of Science, the warm interest which is taken in the United States of America in the success of the measures proposed for the continuation of Magnetic Observatories. Subjoined is the official communication which has since been received :— “ To His Royal Highness Tut Prince Consort, President, and to the other Officers of the British Association for the Promotion of Science. “Tn accordance with the request of the American Association for the Ad- vancement of Science, its officers beg leave to communicate the following resolutions :— Resolved,--That the American Association for the Advancement of - Science regards with great interest the efforts making by the British Association for the Advancement of Science, to induce the re-esta- blishment of the Colonial Magnetic Observatories, for a new series of simultaneous Magnetic and Meteorological observations. Resolved,—That the Officers of the Association be requested to com- municate this resolution to the Officers of the British Association. “ STEPHEN ALEXANDER, President. “ EpwARD Hirtcucock, Vice-President. “'W. CHAvvENET, General Secretary. “ Josepu Lovertne, Permanent Secretury.” “ Springfield, Mass., August 10, 1859.” 3. The Council has been informed that a deputation has been appointed, and will attend at Aberdeen, to invite the British Association -to hold_ its meeting for 1860 at Oxford, and that invitations will also be presented, for 1861 and following years, from Manchester, Cambridge, and Newcastle-upon- Tyne. 6. The following Report was received from the Kew Committee, and was ordered to be entered on the Minutes. Report of the Kew Committee of the British Association for the Advancement of Science for 1858-1859. It is with deep regret that the Committee have to report the decease of the late Superintendent of the Observatory, Mr. John Welsh, who died at Fal- mouth on the 12th of May, where he had removed for a short time for the recovery of his health. Mr. Welsh’s position as a man of science was too well known to require any reference from the Committee, yet they may be permitted to refer to those aspects of it which have come more prominently under their view during the long and pleasant intercourse which has so unhappily come to an untimely termination. Mr. Welsh entered the Observatory on the 27th of August, 1850, as an assistant to Francis Ronalds, Esq., F.R.S., who for some years had superin- tended the management as the Honorary Director. Mr. Ronalds retired in 1852 to reside on the Continent, since which time, with the exception of a short interval, Mr. Welsh has been the Superintendent; and the present efficiency and recognized scientific standing of the Observatory may be assumed to be in a great measure due to the zeal and remarkable ability with which he discharged his duties: ingenious in devising new arrangements, laborious and persevering in their execution, he was eminently qualificd REPORT OF THE KEW COMMITTEE. xli to direct and superintend the arrangements of a practical physical observa- tory. His knowledge of science in general, but more particularly of Meteorology and Magnetism, was extensive and accurate; in all branches of these sciences he was an eminent authority, having clear and comprehensive views, possess- ing also a sagacious insight into remoter possibilities. His zeal for science was signally displayed in the four balloon ascents which he undertook in 1852 with some personal risk, and from which he ob- tained valuable results (Phil. Trans. vol. exliii. part 3). Possessed of an amiable disposition, of singular warmth of heart and sin- cerity of character, his loss as a friend is mourned by all the members of the Committee and by many members of the Association. The published annual Reports of the British Association, and the Trans- - actions and Proceedings of the Royal Society, contain many valuable con- tributions of Mr. Welsh, and these alone would entitle him to be placed in the ranks of those to whom the Science of this country must ever be deeply indebted. Several gentlemen offered themselves as candidates to succeed Mr. Welsh; the Committee, in selecting Mr. Balfour Stewart, who was formerly his Assistant in the Observatory, believe they have appointed a gentleman who is not only competent to fulfil the duty of Superintendent, but who, from the experience he obtained under the direction of Mr. Welsh, is peculiarly fitted for the office. Mr. Stewart entered on his duties on the Ist of July last. He reports that he found all the Assistants discharging their respective duties. Mr. Chambers was assiduously attending to the Magnetical, and Mr. Beckley to the Mecha- nical Department of the Observatory. Mr. Magrath had charge of the Meteorological verifications, and Mr. Whipple he found of much use in the general work of the Observatory. During the past year, in the Magnetical Department, Constants have been determined for a Unifilar Magnetometer belonging to Dr. Pegado, of Lisbon, and also the temperature correction and induction coefficient for its accom- panying magnet. A Dip Circle belonging to Padre Secchi, For. Mem. R.S., and Astronomer at Rome, as also one belonging to Prof. Hansteen, have been compared with the Kew instrument, adjustments made for the determination of total force by Dr. Lloyd’s method, and observations made at the Observatory as a base station. Temperature corrections and induction coefficients have been obtained for magnets R, and R, belonging to General Sabine. Dr. Bergsma, of Utrecht, has received instructions in the use of Magnet- ical Instruments at the Observatory. ' An extensive series of dip observations, and also periodical determinations of Magnetic force and declination, have been made: and a Manual of In- structions, for the use of the Instruments adopted for those purposes at the Kew Observatory, bas been drawn up and printed at the expense of the Admiralty, by whom 250 copies have been presented to the Observatory. The Committee think it right to mention, that the magnetical work, the details of which have now been given, was executed in the absence of Mr. Welsh by Mr. Chambers, in a manner very creditable to his intelli- ence and industry, and sutisfactory to the Committee. The Self-recording Magnetometers have continued in constant operation ; their instrumental coefficients were determined by Mr. Welsh. ‘The death of this gentleman prevented his completing the Report called for at the last xlil REPORT—1859. Meeting of the Association on the Self-recording Magnetical apparatus at the Observatory ; but the Report is in progress of completion by Mr. Stewart, and will be printed in the next volume of the Transactions of the Association. An instrument has been devised at the Observatory for tabulating the values of the magnetic elements from the curves given by the Magnetographs. As the staff of Assistants at the Observatory is not sufficiently large to under- take these tabulations, General Sabine has undertaken to have the results tabulated at Woolwich for every hour; but the instrument is capable of furnishing data for much smaller intervals, and may under special cireum- stances be thus used. The observations connected with the Magnetic Survey made in Scotland by Mr. Welsh, are in progress of reduction by Mr. Stewart, and the result will be presented as a report to the present meeting. Self-recording Magnetic Instruments designed for the first of the Colonial Observatories which have been proposed to Her Majesty’s Government have been completed by Mr. Adie, from drawings prepared by Mr. Beckley from the design of the late Mr. Welsh, and are set up in a wooden house erected near the Observatory, for the purpose of affording an opportunity to the proposed Magnetical observers to be instructed in the use of the Self-record- ing Instruments. Since the last meeting of the Association the unfortunate death of Mr. Welsh has retarded the experiments with the Photoheliograph, but from time to time they have been gone on with, at first by Mr. Chambers, who obtained some very fair results, and latterly by Mr. Beckley, as his other duties have permitted ; and in order that they might be prosecuted more continuously, the Committee have fitted up a Photographic room in close contiguity to the instrument, This addition to the photographic establishment has been at- tended with the most promising results ; and the Committee have satisfaction in reporting that the difficulties which have hitherto presented themselves in the way of a daily photographic record of the sun, appear to be almost entirely surmounted. Since the erection of the photographic room, Mr. Beckley has been enabled to make a series of experiments, and has turned his attention to the exact determination of the chemical focus of the Photo- heliograph, which there was reason to suspect did not correspond precisely with the visual focus ; for although the chromatic aberrations of the object- glass had been specially corrected in order to obtain that result, the second- ary glass, which magnified the image, was not so corrected. It has been found, after repeated trials, that the best photographic definition is obtained when the sensitized plate is situated from 1th to 1th of an inch beyond the visual focus in the case of a 4-inch picture ; and that when this adjustment is made, beautiful pictures are obtained of the sun 4 inches in diameter, which still bear magnifying with a lens cf low power, and show considerable detail on the sun’s surfaces besides the spots, which are well defined. Mr. De la Rue, by combining two pictures obtained by the Photohelio- graph at an interval of three days, has produced a stereoscopic image of our luminary which presents to the mind the idea of sphericity. Under Mr. De la Rue’s direction, Mr. Beckley is making special experi- ments having for their object the determination of the kind of sensitive sur- face best suited for obtaining perfect pictures; for it has been found that the plates are more liable to stains of the various kinds, known to photo-- graphers, under the circumstance of exposure to intense sun-light, than they would be if employed in taking ordinary pictures in the camera. Now that the photographic apparatus has been brought to a workable state, Mr, De la Rue and Mr. Carrington, joint Secretaries of the Astrono- REPORT OF THE KEW COMMITTEE. xl inical Society, propose to devote their attention to the best means of regis- tering and reducing the results obtained by the instrument, provided the funds which may be necessary are placed at their disposal. The difficulties which have stood in the way of bringing the Photo- heliograph into an efficient state of work, were such as required no ordinary degree of perseverance to surmount ; and the Committee have therefore the greater satisfaction in reporting that these have been overcome, in so far as to render the Photoheliograph a valuable recording instrument:—the minor improvements still contemplated have for their object the production of pictures as free as possible from the spots and blemishes to which all photographs are liable, and sun pictures in particular. It was mentioned in the last Report that Mr. Beckley had suggested certain modifications of his anemometer. He was requested to prepare a descrip- tion of this instrument, which description was published in the last volume (page 306) of the Reports of the Association. The verifications of Meteorological Instruments have been continued on the usual plan. The following have been verified from the Ist of July 1858 to the Ist of August 1859 :— Baro- Thermo- Hydro- meters. meters. meters. Par troAduiiralty divin. s002 ekask ds das 4)'O8 120 Wor lthe Board Of Trade. .icls en vies 76 ATA 80 For Opticians and others ............4% 33 317 12 Mota The et Boe, SiGecr cherries 187 911 92 An application having been made by Colonel Sykes for the instruments used by Mr. Welsh in his Balloon ascents, these were got ready and their corrections determined. The instruments, consisting of one barometer, two Regnault’s hygrometers with attached thermometers, eleven separate thermometers, three vacuum tubes obtained from Dr. Miller, and a polari- meter, with their respective fittings, were delivered to Colonel Sykes, and are now in charge of the Balloon Committee. On the 21st of May, 1859, the Chairman of this Committee addressed a letter to the Secretary of the Admiralty, stating that by the direction of the Com- mittee he had been desired to acquaint the Lords of the Admiralty that the Austrian frigate ‘ Novara,’ which left Europe on a voyage of circumnavi- gation and scientific research, was furnished with scientific instruments from the Kew Observatory, that her officers received instruction for their use from Mr. Welsh and his assistants, and that several communications had been re- ceived from the ‘Novara.’ ‘This vessel has since arrived. The following correspondence has taken place between Senhor da Silva of Lisbon and General Sabine. ‘Lisbon, July 11th, 1859. * Srrn,— Having succeeded Dr. Pegado in the direction of the Meteoro- logical Observatory at Lisbon, I shall be very happy if I can assist in, or promote the important operations connected with magnetism that England is about to undertake. “ But previous to promising you on my part, I am desirous of knowing— “1st. If it will be possible to instruct a Portuguese official at Kew. “9nd. If the English Government would be disposed to interest that of Portugal in this scientific expedition. “3rd. To whom we ought to apply in order to complete our collection of xliv REPORT—1859. Magnetic Instruments, having already an Inclinometer of Barrow, a Declino- meter of Jones, and a Unifilar of the same maker. “Finally, to solicit you to aid us with your excellent counsel, of which we are in want. “ You will please pardon my having taken this liberty of addressing you, but wishing to serve science to the utmost of my power, I trust that you will favour me with your aid. “ Accept the assurance of my high consideration and respect. ‘‘T have the honour to be, Sir, “ Your obedient Servant, (Signed) J. A. DA SILVA.” - “ Major-General Sabine, Woolwich.” ‘13 Ashley Place, London, S8.W. * Srr,—I beg to acknowledge the receipt of your letter. I am authorized by the Committee of the Directors of the Kew Observatory to say, that it will give them great pleasure to afford every facility for instruction and practice, both in the self-recording magnetic instruments and also in those designed for absolute determinations, to an officer who may be sent by you for that purpose; and should you desire to have any instruments made in England similar to those in use at Kew, the Committee will be most happy to superintend their construction, verify them, and send them out. In regard to an application from our Government to yours, I am unable at present to say anything, inasmuch as the decision upon the establishment of our own proposed observatories will not be taken until the autumn: the restoration of peace is a favourable event. “TI beg you, Sir, to be assured that it will at all times give me great pleasure to be of any use to your Observatory in my power. “T have the honour to be, Sir, * Your obedient Servant, (Signed) «“ EDWARD SABINE.” “ Senhor J. A. da Silva, Observatorio Meteorologico, Lisbon.” The following Resolution was passed by the General Committee at the last Meeting of the Association at Leeds :— “ That the consideration of the Kew Committee be requested to the best means of removing the difficulty which is now experienced by Officers pro- ceeding on Government Expeditions and by other Scientific travellers, in procuring instruments for determinations of Geographical Position, of the most approved portable construction, and properly verified. That the in- terest of Geographical Science would be materially advanced by similar measures being taken by the Kew Committee in respect to such Instruments, to those which have proved so beneficial in the case of Magnetical and Meteorological Instruments.” The Committee are strongly impressed with the importance of the pre- ceding recommendation, and would have great satisfaction in giving their best attention to the subject, but the works they have in hand are already beyond the pecuniary means placed at their disposal, and the Committee are unwilling to impair the credit which the Kew Observatory is obtaining by undertaking more than the income enables them to accomplish effectively. REPORT OF THE KEW COMMITTEE, xlv The Committee finding that in future they will not require more than one half of the land attached to the Observatory, for which an annual rent of £21 is paid, notice to that effect has been given to Mr. Fuller. In the last Annual Report to the Council at Leeds, the Committee sug- gested “that the time had arrived when strenuous exertions should be made to obtain such an amount of pecuniary aid as would ensure the efficient working of a practical physical observatory ;” and they also stated “that the probable future expenditure could not be fairly estimated under £800 per annum.” At that time the Committee contemplated the engagement of a photographie assistant, and also some other arrangements which they were compelled to forego, as it will be seen, by the financial statement annexed to this Report, that the expenditure of the past year exceeded the income by the sum of £106 2s. ld., the amount of the former being £675 14s. 8d., while the total income was only £569 12s. 7d., £69 12s. 7d. having been received for the verification of instruments: this source of income is year by year decreasing, as explained in a former Report, in consequence of the Govern- ment departments being now nearly supplied with standard meteorological instruments. The Committee, in presenting this Report, have to repeat their former sug- gestions, that means should be taken to obtain effectual pecuniary aid for the support of an establishment which has for so many years laboriously and effectually carried out those scientific objects for which it was founded, more particularly since the appointment of a salaried superintendent, assisted by a competent staff, whose individual services have always been obtained at the most moderate scale of remuneration. Kew Observatory, Aug. 29, 1859. Joun P. Gassior, Chairman. 1859. REPORT xlvi ‘NOLLIOH “ut "6S81 “dag pug ‘gouadyystq pure sZaryIYyS VUINy spunog J4SIy st puey Ut souLTeg oy} 4eYy} puYy pur ‘ow o7 pazuasatd sIOYONOA 9} YIM 4yL paredoioo pue yuNodoe 4} poulUexe Avy T bP P89F 8 6 8 0 GI FE 0 OL OL 6 6 8 Il It 61 0 0 FG [E.-f 2g @ GL LT 6 LE Ote Lon8 8h ta ae 0 Gt 1a 0 O14 0 ¢ 68 0 0 OL 0 0 O0T 0 0 0S 0 0 OST DE oe ae Oe Peet meme ee eee reee ee sasessrnes pury ut sourleg teeeeereseesees SUIOOY (SIUBISISSY Surysiaan yy stseeseesseeceseeseescoecssenseessoonipe JO Ua sreeeeereerecee sogugdxa Aqjad pur o8es0q10g eseserane e179 ‘Aja ppueyg ‘sosuodxy asnoyyT sseenceeseseesousceeeeeresereees SUEY DUG STO) “93vysog pur ‘syoog ‘Arau0neyg ‘SunUIIg “ee**-nOsBTy pue ‘taquadieg ‘1asuomuUoIy tHreseeeeres son (S1OOT, ‘S[RMaICIL ‘snqyereddy "SL 98 ‘ZI ‘ydoag Surpus ‘syoom g¢ ‘071g iteaaeetaaeeeestereeeaseseerrnigOT ap ‘e ‘uve Surpua ‘syaem cz ‘opddiy Ay “9 { eteaeeeeerercenaternseseseensengoe 40 *Z1 ‘3dag Surpua ‘syoam Te ‘Aapyoog “yy FL ‘Sny Burpua ‘read ouo ‘yyeasey “A “fe "9 409 Suipua ‘xeak auo ‘sraquieyg ‘9 6S81‘T 390 Surpud.zdjaenbau0 41e M49 "Gg reyes sib vary} ‘QuapuojuLIedng oye] OF —? 'o79 ‘SaLIe[eg “SLNGWAVd P ¥ 895 G69 see LG Se ceesteeeees suetoydg wory 0 € OF ‘tt aprIy, JO prvog ayy Wory ‘p ‘Ss Ff —S}UMINIYsUT JO UOOyTIOA oy} 10y tereeeeeeeres TOINSBALT, [BIIUIH OY} WOIF POAToooy tereeseeseeeesees qtmMOoOR SB] LOA, VOULTeT “SLdI GOT "6SSI “HI Laquiajdag 02 898 ‘GG Laquiajdag wosf uoynrosspy ysineg ayp fo aaynuumoy ayy ayz Jo syunov0py REPORT OF THE PARLIAMENTARY COMMITTEE. xlvii 7. The Report of the Parliamentary Committee of the British Association to the General Committee has been received by the Council, and is herewith transmitted. Report of the Parliamentary Committee to the Meeting of the British Asscciation at Aberdeen, in September 1859. The Parliamentary Committee have the honour to report as follows :— We have taken the opinion of Counsel on the question, whether it is ex- pedient to cause a Bill to be prepared to facilitate the appointment of new Trustees to Museums and other Scientific Institutions. The Opinion is appended to this Report. A vacancy has occurred in that division of our members who represent the House of Commons, by the retirement of Mr. Edward J. Cooper, of Markree, from Parliament. We cannot but deeply regret the loss of the services of a gentleman who has devoted a great part of his life to the successful promotion of Astrono- mical Science. It will also be for the General Committee to determine whether they will appoint another member of the House of Commons in the place of the Earl of Ripon, who, since his election at Leeds, has taken his seat in the House of Lords. This case is not in terms provided for in the original constitution of our Committee; but we are of opinion that it was intended that no one should cease to belong to our body, as long as he continued a member of either House of Parliament. While, however, there can be little doubt that Lord Ripon continues a member of the Parliamentary Committee, it may still be deemed expedient that the representatives of the House of Commons should not be diminished in number; in which case there will be two vacancies to supply. We re- commend that Lords Enniskillen, Harrowby, and Stanley, and Mr. Stephen- son, who have not attended during the past two years, be re-elected. During the course of last year, an intention was manifested on the part of the Government, of greatly restricting the free distribution of scientific works published at the expense of the public, and of causing the works so undistributed to be sold at the cost price of printing and paper. It is unnecessary to enlarge on the very injurious moral results which would acerue to Science, and the insignificant pecuniary gain to the public likely to arise from the change in contemplation ; for we have reason to believe that the Government have been induced, by the representations which have been addressed to them, to abandon their original intention. WrottesLey, Chairman. 24th August, 1859. Tue OPINION. The 13 and 14 Vict. ¢. 28, is loosely drawn, and I think many cases might arise in which it would be found that its provisions are inadequate ; but, as 1 understand that there is no intention of altering this Act, it is unnecessary to comment on it ; and I pass to the consideration of whether it is practicable to extend the principle of it to personal estate, other than leaseholds, which are included in the existing Act. I confess I do not see how such an enactment as is proposed would work, except by adding to it such conditions as would prevent its being of any practical convenience. The property under contemplation is, of course, stock in the funds and in public companies, debts, and other choses in action :—personal chattels, passing by delivery of possession, there is no diffi- xlvili REPORT—1859. culty about. Let us take the case of Stock in the Funds. A.B. and C..D., trustees of a Society, have £1000 Consols standing in their names. By are- solution of the Society they are removed from the trusteeship, and E. F. and G.H. are appointed. It is proposed to enact that, thereupon, the Stock shall vest in E. F. and G.H.; but, how is the Bank, which knows nothing about trusts, to be induced to pay the dividends to them? There'must be something equivalent to a transfer of the Stock into their names, by direction of the old trustees, or of the Court of Chancery ; and I do not see that any plan can be devised more simple and inexpensive than the present mode of transfer. The Bank of England would certainly oppose any attempt to make them enter on their books that Stock is subject to any trust; and yet, unless’ it appeared on the books that the Stock is held in trust for a Society, it would not be possible to make any provision for a transfer of the Stock on pro- duction of resolutions of the Society. It occurred to me, that Powers of Attorney, for transfer of Stock vested in trustees for Societies, might be exempted from Stamp Duty ; but, on consideration, I do not see how the Bank could know what powers were lawfully exempted, without taking notice of the trusts. The same objections would not apply to all other descriptions of personal property ; but, I presume, if the proposed alteration of the law is not appli- cable to Stock, it would not be thought worth while to make it with reference to other species of property. In the Literary Institutions Act, there is already a section (the 20th) as to the vesting of personal property ; but it does not very clearly appear how it would work in such cases as are above referred to. M. J. B. 15th January, 1859. The following letter has been received from Baron Bentinck, in relation to the assistance given to Dr. Bergsma at Kew Observatory :— “Netherlands Legation, London, 10th September, 1859. “ Baron Bentinck, Minister of the Netherlands, presents his compliments to Major-General Edward Sabine, Vice-President of the Royal Society at Lon- don, and has the honour to inform him that he-has been requested by his Government to express to Major-General E. Sabine the thanks of the Ne- therlands Government for the kind assistance which he has granted to Dr. P. A. Bergsma, when in London with a Government Mission ; and also to con- vey to Major-General Sabine the hopes entertained by his Government that he will in future time continue to aid Dr. Bergsma with his good advices. Baron Bentinck avails himself of this opportunity to offer to Major-General Sabine the assurances of his highest consideration. : | “ BENTINCK.” * Major-General E. Sabine, Vice-President of the Royal Society, London.” RECOMMENDATIONS OF THE GENERAL COMMITTEE. xlix RECOMMENDATIONS ADOPTED BY THE GENERAL COMMITTEE AT THE ABERDEEN MEETING IN SEPTEMBER 1859. {When Committees are appointed, the Member first named is regarded as the Secretary of the Committee, except there be a specific nomination. ] Involving Grants of Money. That the sum of £500 be placed at the disposal of the Council for main« taining the Establishment at Kew Observatory. That Professor Sullivan (of Dublin) be requested to continue his researches on the Solubility of Salts at Temperatures above 100° Cent., and on the mutual Reaction of Salts at such temperatures; and that the sum of £30, which was voted last year, still remain at his disposal for the purpose. That Professor Voelcker be requested to continue his investigation on Field Experiments and Laboratory Researches on the Essential Manuring Constituents of Cultivated Crops; and that the sum of £25 be placed at his disposal for the purpose. That Mr. Alphonse Gages be requested to continue his Mechanico-Che- mical Experiments on Rocks; and that the sum of £25 be placed at his disposal for the purpose. That a Committee, consisting of Dr. R. Angus Smith, Dr. Daubeny, Dr. Lyon Playfair, Rev. W. Vernon Harcourt, Professor Williamson, and Mr. Warren De la Rue, be requested to confer with the Parliamentary Committee with reference to the best mode of taking Scientific Evidence in Courts of Law ; and that the sum of £10 be placed at their disposal for the purpose of meeting the expenses incident to the working of the Committee. That Mr. Robert Mallet be requested to continue his Experiments on Earthquake Phenomena; and that the sum of £25, unexpended last year, be placed at his disposal for the purpose. That a Committee, consisting of the Rev. Dr. Anderson, Professor Ramsay, Professor Nicol, and Mr. Page, be requested to continue the Explorations already begun by Dr. Anderson in the Yellow Sandstones of Dura Den ; and that the sum of £20 be placed at their disposal for the purpose. That a Committee, consisting of Sir Roderick I. Murchison, Mr. Page, and Professor Ramsay, be requested to direct Mr. R. Slimon in his further Exploration of the Upper Silurian Strata of Lesmahagow; and that the sum of £15 be placed at their disposal for the purpose. That a Committee, consisting of Mr. MacAndrew (London), Mr. G. C. Hyndman (Belfast), Dr. Dickie (Belfast), Mr. C. L. Stewart (London), Dr. Collingwood (Liverpool), Dr. Kinahan (Dublin), Mr. J. G. Jeffreys (London), Dr. E. P. Wright (Dublin), Mr. L. Worthey (Bristol), Mr. S. P. Woodward (London), Professor Allman (London), and Professor Huxley (London), be requested to conduct general Dredging Investigations, and printing of Dredging Papers; and that the sum of £50 be placed at their disposal for the purpose. .That a Committee, consisting of Dr. Ogilvie, Dr. Dickie, Dr. Dyce, Pro- fessor Nicol, and Mr. C. W. Peach, be requested to conduct Dredging In- vestigations on the North and East Coasts of Scotland ; and that the sum of £25 be placed at their disposal for the purpose. _ That a Committee, consisting of Professor Kinahan, Dr. Carte, Dr. E. Per- cival Wright, and Professor J. Reay Greene, be requested to conduct Inves- tigations in Dredging Dublin Bay, and to report to the next Meeting of 1859. d 1 REPORT—1859. the Association; and that the sum of £15 be placed at their disposal for the purpose. That a Committee, consisting of Dr. Daubeny and Dr. Lankester, be re- quested to cooperate with Professor Buckman in his Researches on the Growth of Plants, and to report to the next Meeting of the Association ; and that the sum of £10 be placed at their disposal for the purpose. That Professor Allman be requested to continue his Researches on the Reproductive System of the Hydroid Zoophytes; and that the sum of £10 -be placed at his disposal for the purpose. That a Committee, consisting of Dr. George Wilson, Sir John Herschel, Sir David Brewster, Professor Clerk Maxwell, Professor W. Thomson, and Mr. W. Pole, be requested to inquire into the Statistics of Colour-Blindness ; and that the sum of £10 be placed at their disposal for the purpose. That the following Members be requested to act as a Committee to con- tinue the inquiry into the performance of Steam-vessels, to embody the facts in the form now reported to the Association, and to report proceedings to the next Meeting; that the attention of the Committee be also directed to the obtaining information respecting the performance of vessels under Sail, with a view to comparing the results of the two powers of Wind and Steam, in order to their most effective and economical combination ; that £150 be placed at their disposal for this purpose :—Vice-Admiral Moorsom; The Marquis of Stafford, M.P.; The Earl of Caithness; Lord Dufferin; Mr. William Fairbairn, F.R.S.; Mr. J. Scott Russell, F.R.S.; Admiral Paris, C.B.; The Hon. Capt. Egerton, R.N.; Mr. W. Smith, C.E.; Mr. J. E. M¢Connell, C.E.; Mr. Charles Atherton, C.E.; Professor Rankine, LL.D.; Mr. J. R. Napier, C.E.; Mr. R. Roberts, C.E.: Mr. Henry Wright to be Secretary. That Professor James Thomson (of Belfast) be requested to continue his Experiments on the Gauging of Water ; and that the sum of £10 be placed at his disposal for the purpose. Applications for Reports and Researches. That a Committee, consisting of Professor Walker, Prof. W. Thomson, Sir David Brewster, Dr. Sharpey, Dr. Lloyd, Colonel Sykes, General Sabine, and Prof. J. Forbes, be requested to report to the next Meeting at Oxford as to the scientific objects which may be sought for by continuing the Bal- loon Ascents formerly undertaken to great altitudes. That Mr. A. Cayley be requested to continue his Report on the Solution of certain Special Problems in Dynamics. That Dr. Dickie be requested to draw up a Report on the Flora of Ulster for the next Meeting of the Association. That Dr. Carpenter be requested to draw up a Supplemental Report on the Minute Structure of Shells. That the Committee on Patent Laws be reappointed, for the furtherance of the objects set forth in their Report presented to the Association at this Meeting. That a Committee, consisting of Capt. Sir E. Belcher, C.B., Mr. G. Rennie, F.R.S., and Mr. W. Smith, with power to add to their number, be requested to report on the Rise and Progress of Steam Navigation in the Port .of London. That the following Members, viz. Mr. Thomas Webster, Prof. Willis, the Right Hon. Joseph Napier, Mr. Tite, M.P., Mr. William Fairbairn, Mr. Thos. RECOMMENDATIONS OF THE GENERAL COMMITTEE, li Graham, and General Sabine, be appointed a Committee for the furtherance of the objects set forth in the Report of the Patent Committee presented to the Association at this meeting, and that Mr. Webster be requested to act as Secretary to the same. Involving Applications to Government or Public Institutions. That the thanks of the British Association be offered to H.R.H. The Prince Consort, as President of the Association, for the interest he has mani- fested in the continuation of Magnetic Observations; and that he be re- quested, in concert with the President of the Royal Society, to take such steps as may appear most suitable to carry out the recommendation of the two Societies in respect to these observations. That an Electrometer be constructed on the principle of that described by Professor W. Thomson. That it be verified at Kew, and a report of its performance be made to the Association at its next Meeting. That Pro- fessor W. Thomson be requested to carry this into effect, and that he be authorized to communicate with the President and Council of the Royal Society for the purpose of obtaining their cooperation. The Committee of the Section of Mathematical and Physical Science having represented the probable importance of occasional telegraphic com- munication between a few widely-separated ports of Great Britain and Ire- land, by which warning may be given of storms, the General Committee recommend application to the Board of Trade for such an arrangement as may further this object authoritatively. That it is desirable that the British Association should express to Her Majesty’s Government, through the proper authorities, its concurrence in the application made by the Royal Geographical Society to the First Lord of the Treasury, to further a proposed Expedition under Capt. Speke, to ascer- tain if the White Nile has its main source in the Great Nyanga Lake. That in addition to the large and accurate Survey now in progress on the North-eastern coast of China, under the direction of the Admiralty, it is de- sirable to have prepared, with as little delay as possible, Maps on a smaller scale, and extending over a larger area. Communications to be printed entire among the Reports. Mr. Atherton.—On Steam-Transport Economy. Mr. Fairbairn.—On Breaks for Railway Trains. Mr. J. Park Harrison.— On Lunar Influence upon Temperature, with Diagrams. Mr, A. Thomson—On Industrial Schools. Mr. De la Rue.—Celestial Photography. Professor Owen.— Classification of Reptiles. d2 lii REPORT—1859. Synopsis of Grants of Money appropriated to Scientific Objects by the General Committee at the Aberdeen Meeting in September 1859, with the name of the Member, who alone, or as the First of a Com- mittee, is entitled to draw for the Money. Kew Observatory. At the disposal of the Council for defraying expenses ...... Chemical Science. Sutiivay, Professor.—Solubility of Salts ........... tte VoELcKER, Professor.—Constituents of Manures .... 50 Gages, ALPpHONSE.—Chemico-Mechanical Analysis of Rocks Smiru, Dr. ANcus.—Scientific Evidence in Courts of Law. Geology. Mattet, Rosert.—Earthquake Waves...........+.+-+0% AnvERSON, Rev. Dr.— Excavations in Yellow Sandstone of PUTER 5.0%, 3 oacieta ewe ose tge wlersse slekss state alee elite ceoie rants ae Morcuison, Sir R. 1.—Fossils in ee ae Silurian Bassas, Les- mahago ...... oes Zoology and Botany. MacAnprew, Rosert.—General Dredging ..... Sioteres OaiLvir, Dr.—Dredging North and East Coasts af Scotland . Kinauan, Dr .—Dredging i in Dublin Bay Dauseny, Dr.—Growth of Plants eevee vores es oe vere Physiology. ALLMAN, Professor.—Report on Hydroid Zoophytes Witson, Dr.—Colour-Blindness Mechanical Science. Moorsom, Admiral.—Steam-Vessels’ Performance Tuomson, Professor J.—Discharge of Water £ 500 oooo oocoo oo of oooo oo ooco oo Total.... £930 0 O ne GENERAL STATEMENT, lit General Statement of Sums which have been paid on Account of Grants for Scientific Purposes. £ os. d. &) is... 1834. Meteorology and Subterranean Tide Discussions ......cc000e000 20 0 0 Temperature ....., Eessisoekneesren Mle Lhe O 1835. Vitrification Experiments...... cera te Mee NE / aie Dikctstons ... 62 0 0 ae dg ae eon eneits as ae ae 3 cea ears aad ailwavi Gonstants' wcsseussveseccseee > British Fossil Ichthyology son 105 00 ian ang Sua Bevel ore Deeb ah a £167 0 0} Steam-vessels’ Engines....... se. 100 0 0 1836. van in yee Céleste ...... aaa os 4 § Tide Discussions ...... Bae ce GDL Op FO) [aes 1D PACA... »-kterenssonnaenye British ossil Ichthyology ...... 105 0 0 peek raeae Say Fs 7 . Thermometric Observations, &c. 50 0 0 S F 3 Come. 50 0 0 Experiments on long-continued FET SOB MES IU TORR UA ‘easrae Heat 2 bk Aa ae eae Atmospheric Air ....cssseseees ses 16) 10 Rain Gauges sccscscccccsesseseveee 9-13 0 | Castand Wrought Tron........., 40 0 0 Refraction Experiments ......... 15 0 0 ae one Boas tecen eae a Cael Lunar Nutation...,......c00080.8 60 0 0 ases on Solar Specerun rama tts Mee eek Geemoicters fe 15 6 0 Hourly Meteorological Observa- ee tions, Inverness and Kingussie 49 7 8 £434 14 0! Fossil Reptiles weccesseesseeese 118 2 9 1837. Mining Statistics ...,..s:0000004.. 50 0 0 Tide Discussions .......s.00s008 284 1 0 pa Chemical Constants .........00008. 2413 6 Lunar Nutation..........s0000088 70 0 0 1840. Observations on Waves...esesseees OD} Bristol Tides 5<7,. — eon C53 JMO faare) *h > /* sil ides Le 5 ¥ Siyt* | “er. ae pn: Si(igat pike Ade Wak rere es | if Bris tees fe ne WR pie: 4 ape , ul Abate ty) la ws Mie wae Fs B: + _j GRE «4° neh? mn; Put 1D iahave, Yr wigs ES mane en es Mra ayo Ear PF; ca i 7 . wa Rr et: pate 4 a Pee ao fee et i*- ae w par ial s fig ‘ Sie — arPes aE SL as uae H _ 7 > . Pe y ai —_ “ ; ” ri "" Ans ‘ r T - id as _ F . ee 3% . bt Suk A: nile cet. 3 ag ee xx ‘ : 7 “ne ed i | ees vate de; ei 4 if 3 Ban Se 65 3 MPA AR. Spee ‘i I Se ME as 9 Hamen) Klee ey ae Bh LE eae . . 8 3 ars “ag * Syn eb: < ' ‘aga Rae y. Nees oe Fie ag are Bet Wy ws se havea ane ea aot [ A ed ie PL 5 Skul ru ‘ ee ie i hy yl Peed 14 at “en =e , site Ke lest | eS eae a t a y! ‘ iy ~~ ADDRESS BY HIS ROYAL HIGHNESS THE PRINCE CONSORT. GENTLEMEN OF THE BRITISH ASSOCIATION, Your kind invitation to me to undertake the office of your President for the ensuing year could not but startle me on its first announcement. The high position which Science occupies, the vast number of distinguished men who labour in her sacred cause, and whose achievements, while spreading innu- merable benefits, justly attract the admiration of mankind, contrasted strongly in my mind with the consciousness of my own insignificance in this respect. I, a simple admirer, and would-be student of Science, to take the place of the chief and spokesman of the scientific men of the day, assembled in furtherance of their important objects!—the thing appeared to me impossible. Yet, on reflection, I came to the conclusion that, if not as a contributor to, or director of your labours, I might still be useful to you, useful to Science, by accepting your offer. Remembering that this Association is a popular Association, not a secret confraternity of men jealously guarding the mysteries of their profession, but inviting the uninitiated, the public at large, to join them, having as one of its objects to break down those imagi- nary and hurtful barriers which exist between men of science and so-called men of practice—I felt that I could, from the peculiar position in which Providence has placed me in this country, appear as the representative of that large public, which profits by and admires your exertions, but is unable actively to join in them; that my election was an act of humility on your part, which to reject would have looked like false humility, that is like pride, on mine. But I reflected further, and saw in my acceptance the means, of which necessarily so few are offered to Her Majesty, of testifying to you, through the instrumentality of her husband, that your labours are not un- appreciated by your Sovereign, and that she wishes her people to know this as well as yourselves. Guided by these reflections, my choice was speedily made, for the path of duty lay straight before me. If these, however, are the motives which have induced me to accept your lx REPORT—1859. flattering offer of the Presidency, a request on my part is hardly necessary that you will receive my efforts to fulfil its duties with kind indulgence. If it were possible for anything to make me still more aware how much I stand in need of this indulgence, it is the recollection of the person whom I have to succeed as your President—a man of whom this country is justly proud, and whose name stands among the foremost of the Naturalists in Europe for his patience in investigation, conscientiousness in observation, boldness of imagination, and acuteness in reasoning. You have no doubt listened with pleasure to his parting address, and I beg to thank him for the flattering manner in which he has alluded to me in it. The Association meets for the first time to-day in these regions and in this ancient and interesting city. The Poet, in his works of fiction, has to choose, and anxiously to weigh, where to lay his scene, knowing that, like the Painter, he is thus laying in the background of his picture, which will give tone and colour to the whole. The stern and dry reality of life is governed by the same laws, and we are here living, feeling, and thinking under the influence of the local impressions of this northern seaport. The choice appears to me a good one. The travelling Philosophers have had to come far, but in approaching the Highlands of Scotland they meet Nature in its wild and primitive form, and Nature is the object of their studies. The Geologist will not find many novelties in yonder mountains, because he will stand there on the bare backbone of the globe ; but the Primary rocks, which stand out in their nakedness, exhibit the grandeur and beauty of their peculiar form, and in the splendid quarries of this neighbourhood are seen to peculiar advantage the closeness and hardness of their mass, and their inexhaustible supply for the use of man, made available by the application of new mechanical powers. On this primitive soil the Botanist and Zoologist will be attracted only by a limited range of plants and animals, but they are the very species which the extension of agriculture and increase of population are gradually driving out of many parts of the country. On those blue hills the red deer, in vast herds, holds undisturbed dominion over the wide heathery forest, until the sports- man, fatigued and unstrung by the busy life of the bustling town, invades the moor, to regain health and vigour by measuring his strength with that of the antlered monarch of the hill. But, notwithstanding all his efforts to overcome an antagonist possessed of such superiority of power, swiftness, caution, and keenness of all the senses, the sportsman would find himself baffled, had not Science supplied him with the telescope and those terrible weapons which seem daily to progress in the precision with which they carry the deadly bullet, mocking distance, to the mark. In return for the help which Science has afforded him, the sportsman can supply the naturalist with many facts which he alone has opportunity of observing, and which may assist the solution of some interesting problems suggested by the life of the deer. Man also, the highest object of our study, is found in vigorous, healthy development, presenting a happy mixture of i i eee eee ADDRESS. ]xi the Celt, Goth, Saxon, and Dane, acquiring his strength on the hills and the sea. The Aberdeen whaler braves the icy regions of the Polar Sea, to seek and to battle with the great monster of the deep: he has materially assisted in opening these icebound regions to the researches of Science ; he fearlessly aided in the search after Sir John Franklin and his gallant companions, whom their country sent forth on this mission, but to whom Providence, alas! has denied the reward of their labours, the return to their homes, to the affec- tionate embrace of their families and friends, and the acknowledgments of a grateful nation. The City of Aberdeen itself is rich in interest for the Philosopher. Its two lately united Universities make it a seat of Learning and Science. The Collection of Antiquities, formed for the present occa- sion, enables him to dive into olden times, and, by contact with the re- mains of the handiworks of the ancient inhabitants of Scotland, to enter into the spirit of that peculiar and interesting people, which has always at- tracted the attention and touched the hearts of men accessible to the influ- ence of heroic poetry. The Spalding Club, founded in this City for the preservation of the historical and literary remains of the north-eastern counties of Scotland, is honourably known by its important publications. Gentlemen !—This is the 29th Anniversary of the foundation of this Association ; and well may we look back with satisfaction to its operation and achievements throughout the time of its existence. When, on the 27th September, 1831, the Meeting of the Yorkshire Philosophical Society took place at York, in the theatre of the Yorkshire Museum, under the Presidency of the late Earl Fitzwilliam, then Viscount Milton, and the Rev. W. Vernon Harcourt eloquently set forth the plan for the formation of a British Asso- ciation for the promotion of Science, which he showed to have become a want for his country, the most ardent supporter of this resolution could not have anticipated that it would start into life full-grown as it were, enter at once upon its career of usefulness, and pursue it without deviation from the original design, triumphing over the oppositions which it had to encounter in common with everything that is new and claims to be useful. Gentlemen, this proved that the want was a real, and not an imaginary one, and that the mode in which it was intended to supply that want was based upon a just appreciation of unalterable truths. Mr. Vernon Harcourt summed up the desiderata in graphic words, which have almost identically been retained as the exposition of the objects of the Society, printed at the head of the annually-appearing volume of its Transactions :—“ to give a stronger impulse and more systematic direction to scientific inquiry—to promote the inter- course of those who cultivate Science in different parts of the Empire, with one another and with foreign Philosophers—and to obtain a more general attention to the objects of Science, a a removal of any disadvantages of a public kind which impede its progress.” To define the nature of Science, to give an exact and complete definition of what that Science, to whose service the Association is devoted, is and Ixii REPORT—1859. means, has, as it naturally must, at all times occupied the Metaphysician. He has answered the question in various ways, more or less satisfactorily to himself or others. To me, Science, in its most general and comprehensive acceptation, means the knowledge of what I know, the consciousness of human knowledge. Hence, to know is the object of all Science; and all special knowledge, if brought to our consciousness in its separate distinctive- ness from, and yet in its recognized relation to the totality of our knowledge, is scientific knowledge. We require, then, for Science—that is to say, for the acquisition of scientific knowledge—those two activities of our mind which are necessary for the acquisition of any knowledge—analysis and syn- thesis ; the first, to dissect and reduce into its component parts the object to be investigated, and to render an accurate account to ourselves of the nature and qualities of these parts by observation; the second, to recompose the observed and understood parts into a unity in our consciousness, exactly answering to the object of our investigation. ‘The labours of the man of Science are therefore at once the most humble and the loftiest which man can undertake. He only does what every little child does from its first awakening into life, and must do every moment of its existence; and yet he aims at the gradual approximation to divine truth itself. If, then, there exists no difference between the work of the man of Science and that of the merest child, what constitutes the distinction? Merely the conscious self-determination. The child observes what accident brings before it, and unconsciously forms its notion of it; the so-called practical man observes what his special work forces upon him, and he forms his notions upon it with reference to this particular work. The man of Science observes what he in- tends to observe, and knows why he intends it. The value which the peculiar object has in his eyes is not determined by accident, nor by an external cause, such as the mere connexion with work to be performed, but by the place which he knows this object to hold in the general universe of know- ledge, by the relation which it bears to other parts of that general know- ledge. To arrange and classify that universe of knowledge becomes therefore the first, and perhaps the most important, object and duty of Science. It is only when brought into a system, by separating the incongruous and combining those elements in which we have been enabled to discover the internal con- nexion which the Almighty has implanted in them, that we can hope to. grapple with the boundlessness of His creation, and with the laws which govern both mind and matter. The operation of Science then has been, systematically to divide human knowledge, and raise, as it were, the separate groups of subjects for scientific consideration, into different and distinct sciences. The tendency to create new sciences is peculiarly apparent in our present age, and is perhaps inse- parable from so rapid a progress as we have seen in our days; for the ac- quaintance with and mastering of distinct branches of knowledge enables the ADDRESS. lxiii eye, from the newly gained points of sight, to see the new ramifications into which they divide themselves in strict consecutiveness and with logical necessity. But in thus gaining new centres of light, from which to direct our researches, and new and powerful means of adding to its ever-increasing treasures, Science approaches no nearer to the limits of its range, although travelling further and further from its original point of departure. For God’s world is infinite; and the boundlessness of the universe, whose confines appear ever to retreat before our finite minds, strikes us no less with awe when, prying into the starry crowd of heaven, we find new worlds revealed to us by every increase in the power of the telescope, than when the micro- scope discloses to us in a drop of water, or an atom of dust, new worlds of life and animation, or the remains of such as have passed away. Whilst the tendency to push systematic investigation in every direction enables the individual mind of man to bring all the power of which he is capable to bear on the specialities of his study, and enables a greater number of labourers to take part in the universal work, it may be feared that that consciousness of its unity which must pervade the whole of Science if it is not to lose its last and highest point of sight, may suffer. It has occasionally been given to rare intellects and the highest genius, to follow the various sciences in their divergent roads, and yet to preserve that point of sight from which alone their totality can be contemplated and directed. Yet how rare is the appearance of such gifted intellects! and if they be found at intervals, they remain still single individuals, with all the imperfections of human nature. The only mode of supplying with any certainty this want, is to be sought in the combination of men of science representing all the specialities, and working together for the common object of preserving that unity and pre- siding over that general direction. This has been to some extent done in many countries by the establishment of academies embracing the whole range of the sciences, whether physical or metaphysical, historical or political. In the absence of such an institution in this country, all lovers of science must rejoice at the existence and activity of this Association, which embraces in its sphere of action, if not the whole range of the sciences, yet a very large and important section of them, those known as the inductive sciences, exclu- ding all that are not approached by the inductive method of investigation. It has, for instance (and, considering its peculiar organization and mode of action, perhaps not unwisely), eliminated from its consideration and discus- sions those which come under the description of moral and political sciences. This has not been done from undervaluing their importance and denying their sacred right to the special attention of mankind, but from a desire to deal with those subjects only which can be reduced to positive proof, and do not rest on opinion or faith. The subjects of the moral and political sciences inyolve not only opinions but feelings; and their discussion frequently rouses passions. For feelings are “ subjective,” as the German metaphysician has lxiv REPORT—1859. it—they are inseparable from the individual being—an attack upon them is felt as one upon the person itself; whilst facts are “ objective ” and belong to everybody—they remain the same facts at all times and under all circum- stances: they can be proved; they have to be proved, and when proved, are finally settled. It is with facts only that the Association deals. There may for a time exist differences of opinion on these also, but the process of re- moving them and resolving them into agreement is a different one from that in the moral and political sciences. These are generally approached by the deductive process; but if the reasoning be ever so acute and logically correct, and the point of departure, which may be arbitrarily selected, is disputed, no agreement is possible; whilst we proceed here by the zxductive process, taking nothing on trust, nothing for granted, but reasoning upwards from the meanest fact established, and making every step sure before going one beyond it, like the engineer in his approaches to a fortress. We thus gain ultimately a roadway, a ladder by which even a child may, almost without knowing it, ascend to the summit of truth and obtain that immensely wide and extensive view which is spread below the feet of the astonished beholder. This road has been shown us by the great Bacon; and who can contemplate the prospects which it opens, without almost falling into a trance similar to that in which he allowed his imagination to wander over future ages of discovery ! From amongst the political sciences it has been attempted in modern times to detach one which admits of being severed from individual political opinions, and of being reduced to abstract laws derived from well authen- ticated facts. I mean Political Economy, based on general statistics. A new Association has recently been formed, imitating our perambulating habits, and striving to comprehend in its investigations and discussions even a still more extended range of subjects, in what is called ‘“ Social Science.” These efforts deserve our warmest approbation and good will. May they succeed in obtaining a purely and strictly scientific character! Our own Association has, since its Meeting at Dublin, recognized the growing claims of Political Economy to scientific brotherhood, and admitted it into its Statistical Section. It could not have done so under abler guidance and happier auspices than the Presidency of the Archbishop of Dublin, Dr. Whately, whose efforts in this direction are so universally appreciated. But even in this Section, and whilst Statistics alone were treated in it, the Asso- ciation as far back as 1833 made it a rule that, in order to ensure positive results, only those classes of facts should be admitted which were capable of being expressed by numbers, and which promised, when sufficiently multiplied, to indicate general laws. If, then, the main object of Science—and I beg to be understood, hence-" forth, as speaking only of that Section which the Association has under its special care, viz. Inductive Science—if, I say, the object of science is the discovery of the laws which govern natural phenomena, the primary condi- ~ ADDRESS. lxv tion for its suecess is: accurate observation and collection of facts in such comprehensiveness and completeness as to furnish the philosopher with the necessary material from which to draw safe conclusions. Science is not of yesterday. We stand on the shoulders of past ages, and the amount of observations made, and facts ascertained, has been transmitted to us and carefully preserved in the various storehouses of science; other crops have been reaped, but still lie scattered on the field; many a rich harvest is ripe for cutting, but waits for the reaper. Economy of labour is the essence of good husbandry, and no less so in the field of science. Our Association has felt the importance of this truth, and may well claim, as one of its principal merits, the constant endeavour to secure that economy. One of the latest undertakings of the Association has been, in conjunction with the Royal Society, to attempt the compilation of a classified catalogue of scientific memoirs, which, by combining under one head the titles of all memoirs written on a certain subject, will, when completed, enable the student who wishes to gain information on that subject to do so with the greatest ease. It gives him, as it were, the plan of the house, and the key to the different apartments in which the treasures relating to his subject are stored, saving him at once a painful and laborious search, and affording him at the same time an assurance that what is here offered contains the whole of the treasures yet acquired. While this has been one of its latest attempts, the Association has from its very beginning kept in view that its main sphere of usefulness lay in that concentrated attention to all scientific operations which a general gives to the movements of his army, watching and regulating the progress of his im- petuous soldiers in the different directions to which their ardour may have led them, carefully noting the gaps which may arise from their independent and eccentric action, and attentively observing what impediments may have stopped, or may threaten to stop, the progress of certain columns. Thus it attempts to fix and record the position and progress of the different labours, by its Reports on the state of Sciences published annually in its Transactions ;—thus it directs the attention of the labourers to those gaps which require to be filled up, if the progress is to be a safe and steady one ; —thus it comes forward with a helping hand in striving to remove those im- pediments which the unaided efforts of the individual labourer have been or may be unable to overcome. Let us follow the activity of the Association in these three different direc- tions. The Reports en the state of Science originate in the conviction of the necessity for fixing, at given intervals, with accuracy and completeness, the position at which it has arrived. For this object the General Committee of the Association entrusts to distinguished individuals in the different branches of Science the charge of becoming, as it were, the biographers of the period. There are special points in different Sciences in which it sometimes appears 1859. e lxvi REPORT—1859. desirable to the different Sections to have special reports elaborated ; in such cases the General Committee, in its capacity of the representative assembly of all the Sciences, reserves to itself the right of judging what may be of suf- ficient importance to be thus recorded. The special subjects which the Association points out for investigation, in order to supply the gaps which it may have observed, are—either such as the philosopher alone can successfully investigate, because they require the close attention of a practised observer, and a thorough knowledge of the particular subject; or they are such as require the greatest possible number of facts to be obtained. Here science often stands in need of the assistance of the general public, and gratefully accepts any contributions offered, pro- vided the facts be accurately observed. In either case the Association points out what is to be observed, and how it is to be observed. The first is the result of the same careful sifting process which the Asso- ciation employs in directing the issue of special Reports. The investigations are entrusted to specially-appointed committees, or selected individuals. They are in most cases not unattended with considerable expense, and the Association, not content with merely suggesting and directing, furnishes by special grants the pecuniary means for defraying the outlay caused by the nature and extent of the inquiry. If we consider that the income of the Association is solely derived from the contributions of its members, the fact that no less a sum than £17,000 has, since its commencement, been thus granted for scientific purposes, is certainly most gratifying. The question how to observe, resolves itself into two—that of the scien- tific method which is to be employed in approaching a problem or in making an observation, and that of the philosophical instruments used in the obser- vation or experiment. The Association brings to bear the combined know- ledge and experience of the scientific men, not only of this but of other countries, on the discovery of that method which, while it economizes time and labour, promises the most accurate results. The method to which, after careful examination, the palm has been awarded, is then placed at the free disposal and use of all scientific investigators. The Association also issues, where practicable, printed forms, merely requiring the different heads to be filled up, which, by their uniformity, become an important means for assisting the subsequent reduction of the observations for the abstraction of the laws which they may indicate. At the same time most searching tests and inquiries are constantly carried on in the Observatory at Kew, given to the Association by Her Majesty, the object of which is practically to test the relative value of different methods and instruments, and to guide the constantly progressive improve- ments in the construction of the latter. The establishment at Kew has undertaken the further important service of verifying and correcting to a fixed standard the instruments of any maker, to enable observations made with them to be reduced to the same numerical ee ADDRESS. Ixy expression. I need hardly remind the inhabitants of Aberdeen that the Association, in one of the first years of its existence, undertook the com- parative measurement of the Aberdeen standard scale with that of Green- wich,—a research ably carried out by the late Mr. Baily. The impediments to the general progress of Science, the removal of which I have indicated as one of the tasks which the Association has set for itself, are of various kinds. If they were only such as direction, advice, and en- couragement would enable the individual, or even combined efforts of philo- sophers, to overcome, the exertions of the Association which I have just alluded to might be sufficient for the purpose. But they are often such as can only be successfully dealt with by the powerful arm of the State or the long purse of the Nation. These impediments may be caused either by the social condition of the country itself, by restrictions arising out of peculiar laws, by the political separation of different countries, or by the magnitude of the undertakings being out of all proportion to the means and power of single individuals, of the Association, or even the voluntary efforts of the Public. In these cases the Association, together with its sister Society “the Royal Society,” becomes the spokesman of Science with the Crown, the Go- vernment, or Parliament,—sometimes even, through the Home Government, with foreign Governments. Thus it obtained the establishment, by the British Government, of magnetic and meteorological observatories in six different parts of the globe, as the beginning of a network of stations which we must hope will be so far extended as to compass by their geographical distribution the whole of the phenomena which throw light on this important point in our tellurian and even cosmical existence. The Institute of France, at the recommendation of M. Arago, whose loss the scientific world must long de- plore, cheerfully cooperated with our Council on this occasion. It was our Association which, in conjunction with the Royal Society, suggested the Antarctic Expedition with a view to further the discovery of the laws of ter- restrial magnetism, and thus led to the discovery of the southern polar con- tinent. It urged on the Admiralty the prosecution of the tidal observations, which that Department has since fully carried out. It recommended the establishment, in the British Museum, of the conchological collection exhi- biting present and extinct species, which has now become an object of the greatest interest. I will not weary you by further examples, with which most of you are better acquainted than I am myself, but merely express my satisfaction that there should exist bodies of men who will bring the well-considered and un- derstood wants of Science before the public and the Government, who will even hand round the begging-box and expose themselves to refusals and rebuffs to which all beggars are liable, with the certainty, besides, of being consi- dered great bores. Please to recollect that this species of bore is a most useful animal, well adapted for the ends for which Nature intended him, He alone, by constantly returning to the charge, and repeating the same truths and E2 xviii REPORT—1859. the same requests, succeeds in awakening attention to the cause which he advocates, and obtains that hearing which is granted him at last for self-pro- tection, as the minor evil compared to his importunity, but which is requi- site to make his cause understood. This is more particularly the case in a free, active, enterprising, and self-determining people like ours, where every interest works for itself, considers itself the all-important one, and makes its way in the world by its own efforts. Is it, then, to be wondered at, that the interests of Science, abstract as Science appears, and not immediately show- ing a return in pounds, shillings, and pence, should be postponed, at least, to others which promise immediate tangible results ? Is it to be wondered at, that even our public men require an effort to wean themselves from other subjects in order to give their attention to Science and men of Science, when it is remembered that Science, with the exception of Mathematics, was until of late almost systematically excluded from our school and university education ; —that the traditions of early life are those which make and leave the strongest impression on the human mind, and that the subjects with which we become acquainted, and to which our energies are devoted in youth, are those for which we retain the liveliest interest in after years, and that for these reasons the effort required must be both a mental and a moral one? A deep debt of gratitude is therefore due to bodies like this Association, which not only urges the wants of Science on the Government, but furnishes it at once with well-matured plans how to supply them with the greatest certainty and to the greatest public advantage. We may be justified in hoping, however, that by the gradual diffusion of Science, and its increasing recognition as a principal part of our national education, the public in general, no less than the Legislature and the State, will more and more recognize the claims of Science to their attention; so that it may no longer require the begging-box, but speak to the State, like a favoured child to its parent, sure of his parental solicitude for its welfare ; that the State will recognize in Science one of its elements of strength and prosperity, to foster which the clearest dictates of self-interest demand. If the activity of this Association, such as I have endeavoured to describe it, ever found or could find its personification in one individual—its incar- nation, as it were—this had been found in that distinguished and revered phi- losopher who has been removed from amongst us in his ninetieth year, within these last few months. Alexander von Humboldt incessantly strove after do- minion over that universality of human knowledge which stands in need of thoughtful government and direction to preserve its integrity; he strove to tie up the fasces of scientific knowledge, to give them strength in unity. He treated all scientific men as members of one family, enthusiastically directing, fostering, and encouraging inquiry, where he saw either the want of, or the willingness for it. His protection of the young and ardent student led many to success in their pursuit. His personal influence with the Courts and Governments of most countries in Europe enabled him to plead the cause of ADDRESS. lxix Science in a manner which made it more difficult for them to refuse than to grant what he requested. All lovers of science deeply mourn for the loss of such aman. Gentlemen, it is a singular coincidence, that this very day on which we are here assembled, and are thus giving expression to our admira- tion of him, should be the anniversary of his birth. To return to ourselves, however: one part of the functions of the Associa- tion can receive no personal representation, no incarnation: I mean the very fact of meetings like that which we are at present inaugurating. This is not the thoughtful direction of one mind over acquired knowledge, but the pro- duction of new thought by the contact of many minds, as the spark is pro- duced by the friction of flint and steel; it is not the action of the monarchy of a paternal Government, but the republican activity of the Roman Forum. These meetings draw forth the philosopher from the hidden recesses of his study, call in the wanderer over the field of science to meet his brethren, to lay before them the results of his labours, to set forth the deductions at which he has arrived, to ask for their examination, to maintain in the combat of debate the truth of his positions and the accuracy of his observations. These Meetings, unlike those of any other Society, throw open the arena to the cul- tivators of all sciences, to their mutual advantage: the Geologist learns from the Chemist that there are problems for which he had no clue, but which that science can solve for him; the Geographer receives light from the Natu- ralist, the Astronomer from the Physicist and Engineer, and so on. And all find a field upon which to meet the public at large, invite them to listen to their Reports and even to take part in their discussions,—show to them that Philosophers are not vain theorists, but essentially men of practice—not con- ceited pedants, wrapped up in their own mysterious importance, but humble inquirers after truth, proud only of what they may have achieved or won for the general use of man. Neither are they daring and presumptuous unbe- lievers—a character which ignorance has sometimes affixed to them—who would, like the Titans, storm heaven by placing mountain upon mountain, till hurled down from the height attained, by the terrible thunders of outraged Jove; but rather the pious pilgrims to the Holy Land, who toil on in search of the sacred shrine, in search of truth—God’s truth—God’s laws as mani- fested in His works, in His creation. LIST OF PLATES. PLATE I. Illustrative of Mr. Norman Pogson’s paper on three variable stars, R & S, Urs Majoris, and U Geminorum, as observed consecutively for six years. PLATE II. Illustrative of Mr. J. Park Harrison’s paper on Lunar Influence on the Temperature of the Air. PLATES III. IV. and V. Illustrative of Mr. Balfour Stewart’s paper on the Construction of the Self- recording Magnetographs at present in operation at the Kew Observatory. PLATES VI. and VII. Illustrative of Mr. Balfour Stewart’s paper on the Magnetic Survey of Scot- land in the years 1857 and 1858, undertaken at the request of the British Association, by the Jate Mr. John Welsh. ERRATA. Page 4, line 10 from top, for Bayer read Bayer. Page 4, line 11 from bottom, for Bayer read Bayer. Page 6, note, for hyposulphuric acid read hyposulphurous acid. Page 13, line 10 from top, for C?H18N? read C24H!8N2, Page 14, line 8 from top, for glycocol t read glycocol. Page 17, line 4 from bottom, for 3 Cl2Zn read 3 ClZn. Page 20, lines 6, 7 and 8 from top, for (ethylene, ... . naphtaline, &c., by the action..... simpler constitution. Synthesis of organic compounds)t read (ethylene,.... naphtaline, &c.) by the action of heat on organic substances of simpler constitu- tion : synthesis of organic compounds t. Page 20, line 11 from bottom, for Chloracetyl read Chloride of acetyl. Page 22, last line, for O=16 and for 02=16 read O=16 and O?=16. In the list of tribes, page 95, for SHora read Luora; for Bacnats read BAGMATI. Page 99, for Suopa read Lnopa. Page 100, for Bagnatu read BAGMATI. Page 100, for Symsuunatn Triex (Hill-man, probably Thibetan) read Hint-man, probably Thibetan, obtained at Sambhunath. > tie fl ’ ee > - a, 4 =f A " - he eee ‘ 4 Sie iv’ ; . ae j REPORTS | ‘THE STATE OF SCIENCE, REPORTS ON THE STATE OF SCIENCE. Preliminary Report on the Recent Progress and Present State of Or- ganic Chemistry. By Guorcr C. Fostmr, B.A., F.C.S., Late As- sistant in the Laboratory of University College, London. Tue late Mr. J. F. W. Johnston presented to the Second Meeting of this Association, held at Oxford in 1832, a “ Report on the Recent Progress and Present State of Chemical Science.” This Report included both Organic and Inorganic Chemistry, but no subsequent Report exists in which the progress of Organic Chemistry, as a whole, is discussed. It therefore seemed advi- sable to take the year 1832 as the starting-point of the Report, the preparation of which was entrusted to Dr.-Odling and myself, at the Meeting in Leeds last year. On commencing the task, we found that a satisfactory account of the progress of organic chemistry, since that date, would be little else than a tolerably complete history of that branch of science. Believing that such a historical account would be of great value, we made some progress in its preparation. Those, however, who have the greatest acquaintance with the subject, will be the readiest to believe that it was utterly impossible for us to bring such a Report to anything like a state of completeness in time for the present Meeting. We thought, however, that such a general preliminary account as we might be able to give, of some of the most recent discoveries, illustrating some of the ideas most lately introduced into the science, might perhaps have both interest and utility. In the following pages, therefore, in which such a general account is at- tempted, historical completeness has not been aimed at; the object has been rather to place in a clear light the real nature and tendency of some of the most important theoretical views which are now taking a place in the science. The reconciling of the theory of types with the theory of compound radi- cles, which resulted from the discovery of the compound ammonias by Wurtz and Hofmaun, and the discovery of the mixed ethers (or ethers containing two distinct alcohol-radicles) by Williamson, prepared the way for Gerhardt’s classification of chemical substances according to types of double decompo- sition. The system of ideas, of which we may regard this classification as an epitome, has exerted so great an influence on the progress of theoretical chemistry during the last seven or eight years, that it becomes an essential part of a survey like the present to consider what parts of it have been modified or confirmed by recent discoveries. 1859. " B Ff 2 REPORT—1859. Gerhardt’s classification, like every classification which rests on chemical principles, was a system of rational formule. It is very important, there- fore, for our present purpose, to understand clearly at the outset what his formule were intended to express. As he constantly repeated, they were not attempts to represent the arrangement of the atoms of chemical com- pounds, but to represent the groups or atoms, which, in the double decom- positions by which compounds are formed or destroyed, replace, or are re- placed by, other groups or atoms. His types were selected as being the simplest or best known bodies which could be the agents or products of double decompositions similar to those of the substances classified as deri- ving from them. Gerhardt’s formule are, therefore, in the strictest sense chemical, and, as such, ought to be clearly distinguished from formule which are intended to express the molecular arrangement of compounds, formule which, speaking strictly, are physical, not chemical. The nature and importance of the distinction to which we refer will perhaps be made clearer if we recall to the recollection of the Section a recent instance in which it appears to have been overlooked by one of the ablest of living che- mists. Gerhardt had given two different formule for aldehyde, namely, 2 3 C’ H’ O.H and c 7 O, each of which expresses accurately the chemical nature of aldehyde in relation to a particular set of reactions. Kopp, however, found that the specific gravity of aldehyde, calculated from the formula C? H’ O.H, according to a rule which he had deduced from the examination of a considerable number of substances, agreed with the specific gravity found by experiment, but that the specific gravity calculated from 2 3 the formula a O did not agree with experiment. He therefore con- cluded that the first formula was more accurate than the second. Assuming that the rule we have referred to was founded on a sufficient num- ber of accurate observations, such a conclusion would doubtless be correct, were the formule intended as expressions of the molecular constitution of aldehyde so long as it remains such, that is to say, so long as its chemical characters do not come into account; but the facts in question have no bear- ing on the relative accuracy of formule which have reference solely to the reactions by which aldehyde can be formed or decomposed*. The idea of polyatomic radicles and molecules naturally arose out of the attempt to represent polybasic acids according to types of decomposition. The first chemist who used formule expressing the replacement of more than one atom of hydrogen by a single atom of a compound radicle was Professor Williamson+. The views which he had expressed were extended, and the expression of them in chemical formule greatly facilitated, by the introduction, by Dr. Odling}, of a special mode of notation. But the most numerous and most remarkable examples of polyatomic compounds hitherto known, have been furnished by the researches of Berthelot§ and of Wurtz]. In order to explain the nature of polyatomic compounds and the meaning of polyatomic formule, we cannot take a better illustration than the formula (C3 ila 3 for glycerine proposed by Wurtz], H } O*. This formula represents glycerine as deriving from three atoms of water by the substitution of the in- divisible triatomic radicle C* H’ for three atoms of hydrogen ; that is to say, as a hydrate, but a hydrate which differs from ordinary hydrates, just as * Comp. Kexkulé, Ann. Chem. Pharm. evi. 147, note. + Chem. Soc. Quart. Journ. iv. 350. t Ibid. vii. 1. § Ann. Chim. Phys. [3] xli. 216. ll Ibid. lv. 400. q Ibid. xliii. 493. ON THE STATE OF ORGANIC CHEMISTRY. 3 a terchloride differs from a protochloride. Thus a protohydrate, alcohol, 2 5 E in bo, for example, is converted into a chloride by the action of one atom of hydrochloric acid, one atom of water being at the same time elimi- nated,— ‘ OE | o+HCI-H’ 0=C'H' Cl, Alcohol. Chloride of ethyl. and cannot then be any further acted on in the same way. Glycerine is similarly converted into a chloride, with elimination of an atom of water, by the action of one atom of hydrochloric acid, 3 5 Cir | OF H.Cl-H? O=C' HT 0° Cl; Glycerine. Monochlorhydrin. but the product in this case can again produce the same reaction with a second, and even with a third atom of hydrochloric acid :— C* H’ O? C1+H Cl—H’*® O=C? H’ O CP Monochlorhydrin. Dichlorhydrin. C* H’O Cl + H Cl—H? O=C? H’ CP Dichlorhydrin. Trichlorhydrin. And in general terms, we may express the difference between a polyatomic body and a monatomic body, deriving from the same type, by saying that, with the same reagent, both produce similar reactions, but that a greater quantity of the reagent (two, three, or four times as much, according as the substance is di-, tri-, or tetratomic) is required to react to the greatest pos- sible extent with the polyatomic body than with the monatomic body. The consideration of the following and similar series of bodies— Cee tie Ore. oe. Marsh-gas, Os ie © SO aN Chloride of methyl, 0h cS ere ee BS Chloride of methylene, CHA GE G28 ei Ae 8k Chloroform, GER oom mule # Bichloride of carbon, throws great light upon the mutual relations of monatomic and polyatomic substances. ‘The second term of the series is a monatomic chloride; it re- acts with one atom, but not with more, of potash, ammonia, &c. The third is a diatomic* chloride, the fourth a triatomic t chloride, and the fifth a te- tratomict chloride. ‘The radicles which these four chlorides respectively contain are (CH*)!, (CH’)", (CH)!", and (C)¥, all formed from marsh-gas (CH), the first term of the series, by the removal of hydrogen; and the number of atoms of hydrogen which must be removed to form each radicle denotes the atomic value of that radicle. In other words, chloride of methyl, CH? Cl, can, under a variety of conditions, part with its chlorine in exchange for other substances, whilst its carbon and hydrogen remain in unaltered combination, having the characters of a monatomic radicle. But, under cer- tain other conditions, chloride of methyl can exchange one-third, two-thirds, or even the whole of its hydrogen against an equivalent quantity of chlorine ; and the compounds which are formed, containing C H’* Cl’, C HCI’, and C CI’, * No reactions corresponding to this view of chloride of methylene are yet known, but the analogy of iodide of methylene (Comp. Buttlerow, Ann. Chim. Phys. [3] liti. 313) is sufficient for our present purpose. t+ Comp. Kay, Chem. Soc. Quart. Journ. vii. 224; Hofmann, Proc. Roy. Soc. ix. 229. { Comp. Hofmann, Proc. Roy. Soc. ix. 284. B2 4 REPORT—1859. can in their turn take up other substances in exchange for their chlorine, while the remainder of their elements (carbon, or carbon and hydrogen) pass into new compounds with the properties of polyatomic radicles. These relations may be stated still more generally as follows :—compounds formed upon the molecular type CH* are either incapable of undergoing double decomposition, or are monatomic, diatomic, triatomic, or tetratomic, according to the number of atoms of hydrogen which are replaced, and to the nature of the substance by which it is replaced*. A remarkable instance of a series of compounds presenting precisely similar relations has recently been pointed out by Bayert, in his researches upon the compounds of methyl with arsenic. If we now consider some of the most important reactions by which com- pounds are converted into others of greater atomic value, we shall find that in almost all cases the process is essentially the same as in those already referred to. 1. Acetic acid, C? H*O’, which in most of its reactions behaves as a monatomic hydrate, is converted by the action of chlorine into chloracetic acidt, C*? H*Cl1O*. This substance can easily be made to part with its chlorine and to take up in its place other elements. For instance, when heated with an alkaline hydrate, it exchanges its chlorine against an atom of hydrogen and an atom of oxygen, thus— C* H’ ClO*+ KHO=C? H* 0°+ KCl, Chloracetic acid. Glycolic acid. giving rise to an alkaline chloride and a biatomic acid, glycolic acid§. Again, chloracetic acid is decomposed by ammonia into hydrochloric acid and glycocol||, also a biatomic substance :— C? H’ C10°+ H*N=C? H’ NO’+ HCl. Chloracetic acid. Glycocol. In these two cases it admits of question whether the change from a mon- atomic to a diatomic compound takes place when the acetic acid is converted into chloracetic acid, or in the subsequent metamorphosis of the latter body. But at whatever stage of the process the change occurs, it is essentially the same, and consists in the replacement of an atom which, in ordinary double decompositions, acts as a constituent part of the radicle of the acid, by an atom or group which, in similar circumstances, acts as though it were ex- ternal to the radicle. 2. Chloride of kakody], AsMe’Cl, is a monatomic chloride, but, acted upon by chlorine at the temperature of 40° to 50° C., it is converted into bichloride of arsenmonomethy], AsMeCl’, a diatomic chloride (Bayer). Here, again, the change may be described as the replacement of an atom (methyl) which is inactive with regard to double decompositions, by an atom (chlorine) which is active. 3. An increase in the quantity of oxygen contained in a compound gene- rally increases its atomic value. An instance of this has already been re- ferred to in the case of acetic and glycolic acids. We may mention as further examples— Alcohol sa-ss)scss C?H°O Tritylic aleohol.. C*’H*®O Monatomic.° Glyco) ngs ae C’H°O? Tritylic glycol .. C* H*®O* Diatomic. Ethyl-glycerine(?) C? H°O*? Glycerine...... C’ H°O* Triatomic. * Comp. Odling, Journ. Roy. Instit., March 16th, 1855. + Ann. Chem. Pharm. cy. 265; more fully, cvii. 257. t R. Hoffmann, Ann. Chem. Pharm. cii. 1. § Kekulé, ibid. cy. 286. || Cahours, Ann, Chim; Phys, [3] liii. 355. ON THE STATE OF ORGANIC CHEMISTRY. 5 4, The conversion of benzoic, toluylic, cuminic, and anisic acids into the so-called benzamic, toluamic, cuminamic, and anisamic acids is a change equivalent to that of acetic acid into glycocol, and is therefore the change of a monatomic into a diatomic substance. We shall return hereafter to the consideration of the formulze of glycocol and its analogues. The following are examples of the transformation of polyatomic into mon- atomic compounds :-— 1. Lactic acid, C’ H’O® (diatomic), reacts with pentachloride of phos- phorus, giving chloride of lactyl*, C? H*OCI’. Chloride of lactyl is decom- posed by water into hydrochloric and chloro-propionic + acids,— C* H*OCl?+H’?O=C’ H’O’ Cl+ HCl, Chloride of lactyl. Chloropropionic acid, and chloropropionic acid is converted by nascent hydrogen into propionic acid (monatomic). This transformation of lactic into propionic acid is evidently the converse of the transformation of acetic into glycolic acid which is mentioned above. 2. By similar reactions, salicylic acid, C’ H®O* (diatomic), is converted into chloride of salicyl, C7? H*O Cl’, and into chlorobenzoic} acid, C’ H’O* Cl. 3. The action of iodide of phosphorus on glycerine, C’ H® O° (triatomic), gives iodopropylene, C* H’ I, from which allylic aleohol, C* H® O (monato- mic), can be easily obtained. Typical formule being representations of reactions, it follows that if a sub- stance affords two or more distinct kinds of reactions, either of formation or of decomposition, it may be consistently represented by formule deriving _ from a corresponding number of distinct types. Benzamide is a substance of this nature. Its formation by the reaction of chloride of benzoyle, or of benzoate of ethyl, upon ammonia, its decomposi- tion by alkaline hydrates, and many other reactions, all characterize it as de- riving from the type ammonia; accordingly it is commonly represented by the formula Cc’ H’O H N. H But when acted upon by pentachloride of phosphorus, it is decomposed pre- cisely as though it derived from the type water, and gives rise to the chloride of a radicle containing nitrogen, chloride of benzamidyl§, C’ H® NCI. The rational formula of benzamide which results from this reaction is 7 6 NI e iy s } O, deriving from the type if O. . The substance described by Williamson || as chlorohydrated sulphuric acid, S H O*Cl, may, in like manner, be represented either as a chloride or asa hydrate. Represented as a chloride, it takes its place in the following series of compounds containing the same radicle :— Chloride.... SH O*,Cl, Chlorohydrated sulphuric acid. Hydrate .... = _ } O, Sulphuric acid. * Wurtz, Ann. Chem. Pharm. cvii. 194. + Ulrich, Ann. Chem. Pharm. cix. 268; Chem. Soc, Quart. Journ. xii. 23, + Chiozza, Ann. Chim. Phys. [3] xxxvi. 102. § Gerhardt, Traité de Chimie Organique, iv. 762; Ann. Chim. Phys. [3] xlvi. 172, || Proc. Roy. Soc. vii. 11. q Comp. Schiff, Ann, Chem, Pharm, cii. 144, 6 REPORT—1859. - 3 Potassium-salt : e } O, Acid sulphate of potassium. Miner’? se4 : rays } O, Sulphovinic acid. S H O° PANE 5:50:00 H N, Sulphamic acid. H R ; S ClO? , epresented asa hydrate, it becomes H O, and enters into the follow- ing series :— Chloride .... SCl10O’, Cl, Chlorosulphuric acid. 2 Hydrate..... : Fi ¥ \ O, Chlorohydrated sulphuric acid. mide 3 S Cl O° , , , Potassium-salt K O, Rose’s sulphate of chloride of potassium. Ether S ClO") ©, Chlorethylated sulphuric acid * Peres C2 EP } ylated sulphuric acid *. But the rational formula which Williamson gave for his compound was neither of these, but a combination of them into one; namely, Cl } SO? ike This formula represents a substance at once a hydrate and a chloride, formed Cl from the double type Ht the two atoms of which are held together by O H ? the diatomic radicle S O° replacing one atom hydrogen in each. It is obvious that a substance so constituted would react either as a chloride or as a hy- drate, according to the nature of the substances with which it was brought in contact. Until the discovery of chlorohydrated sulphuric acid, the idea of poly- atomic radicles was confined to the replacement of two or more atoms of hydrogen in one or more molecules of a single typical substance. ‘The notion of mixed types, of which this substance afforded the earliest} illustra- tion, has been applied by Kekulét, with remarkable ability, to explain the constitution of a great number of highly complex substances. Every substance which can be represented by a formula deriving from a mixed type may also be represented by two or more formule, each deriving from a siinple type, but containing a comparatively complex radicle. In all cases the choice is open between complex types with simple radicles, and simple types with complex radicles§. * R. Williamson, Chem. Soc. Quart. Journ. x. 97. t Odling, in a paper already quoted (Chem. Soc. Quart. Journ, vii.), represented hyposul- penne Al elie st ome H2 : phuric acid as SO? }o deriving from the type He oF , which, however, may be regarded as H a mere variation of the type io} + Ann, Chem. Pharm. civ. 129. § Comp. Kopp, Jahresber. 1857, 271. ON THE STATE OF ORGANIC CHEMISTRY. vi We may illustrate this by reference to a substance which has been men- tioned above; namely, benzamide. We have shown how, according to the particular reactions which we take into consideration, benzamide may be re- C’H’O C’H'N garded either asa nitride or as an oxide; as = N, or as H } oO. Both of these formule derive from very simple types, but each contains a somewhat complex radicle,—a radicle containing three different elements. If, however, we combine these two expressions, and, by means of a poly- 3 atomic radicle, represent benzamide as deriving from the mixed type 72 9 } ’ H 3N we obtain the formula devges i) ule H’ }O This is a more general expression than either of the other two, for it gives us even more information as to the possible transformations and derivatives of benzamide than both of them taken together. Corresponding formule for the other members of the benzoic group may be obtained from it by supposing the water or ammonia of the type replaced by other molecules. For example :— Hho 7Epyre Benzoic acid ......-..+.----: Ae a ) of , type E a H : 5 Cl HC Chloride of benzoyl...... vee (CUED)! { o> type te oO H H N H}> N Chloride of benzamidyl ........ (C’H’)!" , type E , Cl H Cl H \w ih} N n r (C" zy Unknown analogue of acediamine H } , type LH ; H aon Product of the action of pen- Cl HCl tachloride of phosphorus}.. (C’H’)'" 4 Cl, type Ec Cl, on chloride of benzoyl*. . Cl HCl a (C*H*y Ny type * HPN: In all cases, formule derived from complex types and containing simple radicles, are of a higher degree of generality than formule derived from simple types and containing complex radicles. This will become evident if we consider a little the real import of types and radicles. It is clear, in the first place, that a formula derived from a single molecule of any given type, only tells us that the body which it represents can undergo once over the decompositions which characterize that particular type. If we want to express that it can undergo the same decomposition twice or three times, we must represent it as deriving from two, or from three molecules of the same type. Or, if we want to express that it can undergo decompositions of two * Schischkoff &,Rosing, Compt. Rend. xlvi. 367 ; Jahresber. 1858, 279. 8 REPORT—1859. or more distinct kinds, we must give to it a formula derived from the com- bination of the types corresponding to the decompositions in question ; that is to say, the more numerous are the reactions which we take into account in constructing the rational formula of any substance, the more complex must be the type from which that formula is derived. Secondly, it is obvious that complication of type involves simplification of radicles; for in any com- pound, the greater the number of atoms which are regarded as belonging to the type, the smaller the number left to constitute the radicle. We see therefore that rational formule of the highest possible degree of generality would contain radicles of the greatest possible degree of simplicity ; that is, consisting of single atoms of the elementary bodies. And in the case of every compound of which our knowledge is extensive enough for us to be able to trace, through a series of reactions which affect it more and more deeply, the successive separation of all its atoms, one from another, or the process of the recombination of these atoms into the original compound, the rational formula, which would express the sum of our knowledge respecting it, would actually take the form we have mentioned. In illustration of these remarks, we may consider briefly the known reac- tions of acetic acid, and the way in which they may be expressed by rational formule. 1. The relation of acetic acid to the acetates shows that it contains an atom of hydrogen which can be separated from the other atoms. The rational formula expressing this is OPH OF. 2. In the decomposition of acetic acid by pentachloride of phosphorus, and by pentasulphide of phosphorus, as well as in its conversion into aceta- mide, one half of its oxygen is separated from it. Considering this result in connexion with the formula deduced in (1), we obtain the formula C?H°0.H.O CH S83 . U,; or H ? which expresses that an atom of hydrogen, or an atom of oxygen, or both together, may be separated from acetic acid, while the rest of its atoms remain combined. 3. Acediamine, C? H® N*?*, acetonitrile, C?H® N, and the substance C°H’ Cl’ (formerly terchloride of acetyl, but now without a name), are derivatives of acetic acid in which it is represented by the triatomic radicle C* H®. Hence the last formula must be replaced by 2 Bsyr 2 (C 7 ) or derived from the type Ho f > 4. There are many reactions in which a compound belonging to the car- bonic group and one belonging to the methylic group are formed simul- taneously from acetic acid or one of its derivatives, or in which an acetic compound is formed synthetically from a compound of the carbonic group and one of the methylic group. We may mention— A) of decompositions, the formation of a carbonate and acetone by the distillation of an alkaline acetate by itself, or of a carbonate and. marsh-gas when it is distilled with an alkaline hydrate ; the electrolytic decomposition of acetic acid; the formation of kakodyle; the produc- tion of disulphometholic acid and carbonic anhydride by the action of fuming sulphuric acid on acetonitrilet ; the decomposition of glycocol * Strecker, Ann. Chem. Pharm. ciii. 328. + Buckton and Hofmann, Chem, Soc. Quart. Journ. ix. 243; Ann. Chem. Pharm. c. 133. j ON THE STATE OF ORGANIC CHEMISTRY. 9 when distilled with baryta, into methylamine and carbonate of ba- rium* : (B) of formations, the production of acetate of soaium from so- dium-methyl and carbonic anhydride+ ; of acetonitrile from iodide of methyl or methyl-sulphate of potassium and cyanide of potassium. To indicate the possibility of these reactions, we must break up the radicle C? H®, contained in the last formula, into C.C H*. The formula of acetic acid will then be n°? HH LO derived from the type | H by the replacement of one atom of hydro- H O aa H gen in the type H H by the monatomic radicle C H*, and the replacement of the other atom together with all the hydrogen of one atom H°O, and half the hydrogen in the second atom H?0, by the tetratomic radicle (C)". 5. The addition of one atom oxygen to the molecule of acetic acid has the effect of rendering a second atom of hydrogen (see 1) separable from the rest (production of glycolide, action of pentachloride of phosphorus) {. We can express this by the formula H }(CH*)" (C)v to ; O derived from the type Ss H B| ao HH H Hf? H Hl? The addition of one atom oxygen to this formula would convert one of the molecules of H H in the type into H?O. The formula of glycolic acid, the substance formed by combining acetic acid with an atom of oxygen, would therefore be O — O a —— — ge hd ve hc ph HH - m cor| 10 erive ro H i }O a H H O H . * Cahours, Ann. Chim. Phys. (3) lili. 353. + Wanklyn, Ann. Chem. Pharm. cxi. 234. t Acetic acid + 1 atom oxygen = glycolic acid. We may venture to affirm that gly- colic acid would react like lactic acid with pentachloride of phosphorus. 10 REPORT—1859. 6. The addition of two atoms of oxygen to acetic acid produces a homo- logue of glyceric acid, containing C* H*O**. We are justified by analogy in assuming that in this compound three out of the four atoms of hydrogen are separable from the carbon. The possible production of such a compound is indicated by the formula O derived from Cr : Hg 7, cay HH 5 H} 7. The last formula expresses every possible decomposition of acetic acid except the complete separation of its carbon and hydrogen, which occurs when 1 of the latter is replaced by a metal and the remaining 3 by chlorine, as in a metallic terchloracetate, or when acetic acid is completely oxidized into carbonic anhydride and water. To express such reactions as these, in connexion with those already considered, acetic acid must be represented as built up of separate elementary atoms, without the subordinate combination of even two of them into a compound radicle. For in the reactions which have been enumerated, all the atoms of which acetic acid is composed, are one by one separated from each other; so that not one of them remains combined directly or indirectly with any of the rest. Hence the formula at which we finally arrive, the most general that it is possible to give, is the following :— derived from H 11° or one of equivalent meaning. In this formula all the atoms are represented as entering into combination on an equal footing, and each in turn may be regarded as a radicle or part of the type. Before leaving the subject, it is worth while to point out that each set of relations which we have successively considered, in order to generalize more and more the formula of acetic acid, has in its turn been made the founda- tion of a separate rational formula. Upon the binary theory of acids, acetic acid receives the formula C* H*® O*.H, which is the same in form and meaning as that given in (1). The formula given by Williamson and Gerhardt (2) was intended to express the relation of acetic acid to chloride of acetyl, acetamide, &c. Liebig’s for- * Perkin and Duppa, Chem. Soc. Quart. Journ. xii. 6. ij ON THE STATE OF ORGANIC CHEMISTRY. 11 mula, C' H’, O°. HO*, indicates its connexion with C* H® C?’* (the old ter- chloride of acetyl), aldehyde and other substances containing C* H°* (3)+- Reactions of the kind mentioned in (4) led Kolbe to adopt the formula H HO.(C’ BYC*, O**,. Dumas wrote acetic acid C* HO’. HO*, to express H that that portion of the hydrogen which cannot be replaced by metals, can be removed and replaced by other elements, e. g. chlorine (5, 6, and 7). The formula which we have given as the most general of all is nothing more than a combination of all these, and therefore enables us to recognize the value of eacht. Similar considerations applied to any of the derivatives of acetic acid would lead us to adopt for them formule of the same degree of generality ; for instance, for chloride of acetyl,— Ht in| H leoy H heey H f : J , and for acetamide (cy }(oy" : (y*{ JO H} avy" And in proportion as our knowledge of the genetic relations of any class of compounds is increased, so will their rational formule approach more and more nearly to the same form. All formulz which come short of this are but imperfect descriptions of the bodies which they represent;-for it is evident that a formula containing a compound radicle cannot represent re- actions in which the elements composing that radicle are separated from each other. Nevertheless, for the expression of those relations with which we are most frequently concerned, and for the purposes of classification, it would be of no advantage that the most general formulz should be employed. The relation between any two compounds is best expressed by whatever particular abbreviations of the general formule represent most simply and distinctly the extent of their similarity and difference; while, for purposes of classification, it is essential that all bodies should receive formule of a comparable degree of generality ; and in the majority of cases, the possible degree of generality is but small. Hence Gerhardt's formule, since they express just those reactions with which we are most familiar, and can be applied to every compound of which we can be said to have any chemical knowledge at all, are better adapted than any others to the ordinary require- ments of science in its present state. On the other hand, it cannot be doubted that the chemical character of every substance is affected in a certain definite degree by each separate atom that it contains. And the only way by which we can hope ultimately to ascertain the true chemical value of the elements, or, in other words, to trace the full connexion between the properties and composition of compounds, is by comparing, when possible, (what we may call) their elementary formule. Moreover, we ought not to forget that any classification of chemical com- pounds, which is not founded upon the consideration of their elementary formula, that is, upon the consideration of their dotal reactions, however *C=6,H=1,0 =8. + Schischkoff, Ann. Chim. Phys. [3] xlix. 355, has represented acetic acid by precisely the same formula as that given in (3). t For a list of nineteen different formule for acetic acid, see Kekulé, Lehrb. d. Organ, Chem., p. 58. 12 REPORT—1859. well it may correspond to any particular stage in the development of science, can never be more than a temporary expedient, which must be replaced sooner or later by a classification framed according to more general prin- ciples. The discoveries which have led to, or resulted from, the development of the theory of polyatomic radicles, have caused a corresponding extension of our notion of a chemical family or group. ‘The principal relations of com- position which have hitherto been observed among compounds of the same natural family and deriving from the same type, may be expressed by the following formule, in which 2 and a are always whole numbers and z always greater than x :— 1 al Slee Gey y ce noo O? ” oun * Kin 0%, 10 CO” yen +2) 0%, + 1) de suite ° 2, sei telat tea 02, es C"H?"— 93, 8. CP yt) 04, 11. CO” yer—242) 0%, 8. CPE? O86. C" HH" 04, 9, C°H™"-*#9 OF, 19, C™ Ht) C9, As a special example we may take the tritylic (or propionic) group, in which as yet the number of known terms is more numerous than in any other. Here »=3, x=0, and the above formule become 1. C?H*°O 4c C* HO® Ae TAO: 10. C® H? O* ? Tritylic alcohol. Propionic acid. Pyruvic acid. 2, C* H’ O? 5. C* H’ O° SiC HO 11. C? H?O% Tritylic glycol. Lactic acid. Malonic acid. Mesoxalic acid. SAC aT OF 6:46 70" 9. C° H*0° 12. Cone Glycerine. Glyceric acid. Tartronic acid. 2 The substances which these formule express are all hydrates,—alcohols or acids. It will easily be understood that around each of them, considered as a primary compound, a large number of derivatives,—ethers, anhydrides, chlorides, nitrides, &c.—will arrange themselves. Thus, formula 1 repre- sents, primarily, the monatomic alcohols. To the list of bodies belonging to this class Berthelot * has recently added cholesterine, C*’ H* O (n=26,x=5) (?), and Borneo camphor or camphol, C°H™*O (n=10, w=2). The first of these substances is homologous with cinnamic alcohol, C’H’°O; the second is as yet without homologues. Secondarily, it represents all bodies which may be supposed to contain the same radicles as any actual or possible monatomic alcohols. Here, therefore, come the simple and double ethers, the chlorides, iodides and the like derived from monatomic alcohols ; also the corresponding alkalies containing nitrogen, phosphorus, or arsenic ; compounds containing metals, as kakodyl, zinc-ethyl, &c., and many other bodies which these will serve to suggest. Formula 2 (derived from 1 by the addition of an atom of oxygen) re- presents the diatomic alcohols or glycols, and such other substances as may be supposed to contain similar diatomic radicles. The substances belonging to this class are— (A) the glycols}, of which there are already known ethyl-glycol, C* H’ O*, propyl-glycol, C® H® 0’, butyl-glycol, C* H” O*, amyl-glycol, C’ H” O’, probably also anisic alcoholt, C* H* O°, and saligenine, * Ann. Chim. Phys. [3] lvi. 51 (1859). + Wurtz, Ann. Chim. Phys. [3] lv. 400. 2 pent and Bertagnini, Ann, Chem. Pharm. xcyiii. 188 ; Chem. Soc. Quart, Journ. ix. 190, ON THE STATE OF ORGANIC CHEMISTRY. 13 C7 H’ O°, and derivatives from them containing the same radicles ; and (B) certain substances which behave as though they contained dia- tomic alcohol-radicles, although the corresponding alcohols have not yet been obtained. Among these latter we may mention iodide and biacetate of methylene*; the substances obtained by Wicke+ and by Engel- hardtt from chlorobenzol, substances which appear to be the methylate, ethylate, acetate, valerate, benzoate, &c. corresponding to a still un- i 6 known diatomic alcohol, C Hef O*, isomeric (or identical?) with sali- genine, to which it also seems probable, from the experiments of Engel- hardt§ and Borodine||, that hydrobenzamide, C? H™® N?’, stands in the same relation that, as has been shown by Hofmann, Cloéz’s so-called propylia (properly terethylenamine) does to glycol, or as terethylamine does to alcohol. Formula 3 (derived from 2 by the addition of an atom of oxygen) is representative of glycerine, its derivatives, and their analogues. Among compounds comparable to the derivatives of glycerine are chloroform and analogous substances, such as terchloride of acetyl, C? H’ Cl’, and the sub- stance C‘ H’ Br’ obtained by the action of excess of bromide of phosphorus on butyric acid** ; also the cyanides of the alcohol-radicles if regarded as 2 73\" derivatives of ammonia ; acediamine, (Cc oe \ N’; Schischkoft’s ++ terni- troaceto-nitrile, (C? (NO*)*)" N, and the substance formed from it by the action of sulphydric acid, having the composition of binitro-acediamine, 2 2\2\rrr eH a? ) tw (“ Dinitrammonyl der Essigsturereihe”), and various substances formed by the reaction of pentachloride of phosphorus with monatomic amides, which will be referred to hereafter. : Formula 4 (derived from 1 by the substitution of O for H”) represents monobasic acids containing O*, such as the acids of the acetic, acrylic and benzoic series and their derivatives. To this class of bodies there has been lately added by Dr. Hofmannft, sorbic acid, C’ H® O* (n=6, 7=2). Formula 5 (derived from 4 by the addition of an atom of oxygen) re- presents the acids homologous with carbonic acid, namely glycolic, C* H'* O°," lactic, C? H® O°, &c., and acids analogous to these, such as oxybenzoic, C’ H® O°, with their derivatives. The list of these acids has recently been increased by the addition of glyoxylic§§ acid, C? H* O° (n=2, a=1), buty- lactic acid |||], C‘ H® O° (n=4, 2=0), and oxycuminic] 4 C* H® O° (x=10, x=4). (C? EH? oO)" Among their derivatives are benzo-glycolic acid, C’H’O + O°, benzo- H (C2) H*O)! lactic acid, C’ H’O O?, and, in a certain sense, such acids as chloracetic, * Buttlerow, Ann. Chim. Phys. [3] liii. 313. + Ann. Chem. Pharm. cii. 356. + Chem. Gaz. 1857, 424. § Ann. Chem. Pharm. ex. 77. || Ibid. 78. q Proc. Roy. Soe. ix. 150. ** Berthelot, Jahresber. 1858, 280. tt Ann. Chim. Phys. [3] xlix. 320. Schischkoff and Rosing, Ann. Chem. Pharm. civ. 249. +t Chem. Soc. Quart. Journ. xii. 43. §§ Debus, Ann. Chem. Pharm. c. 1; cii. 29. ||| Wurtz, Ann. Chem. Pharm. evii. 197 ; Ann. Chim. Phys. [3] lv. 456, 460. {{ Cahours, Ann. Chim. Phys. [3] liii. 338. i REPORT—1859, Cl } Cl } C? H’Cl0’=(C? H20)""? _ |, chlorobenzoie, | C7H*C10*=(C’H' Oy": |, i: gia 2 @) Tigao fo, , »magiel sulphacetic*, | C? H* SO°=(C* H’ O)" and So?) os ) }O Hy jo sulphobenzoic*, { C’ H® SO°=(C’ H* oy" ; also glycocol, (S Q?)!! a alanine, leucine, benzamic acid, toluamic acid, cuminamic acid, &e. These last-mentioned substances are intermediate in their properties between deri- vatives of the type H* O and those of the type H* N; they must therefore be regarded as deriving from the type HO , that is, as glycolamic, lacta- § § YP® +N sly mic, oxybenzamic, oxytoluamic, &c. acids; (e.g.glycocolt, C* H® N O?= iL O (C* H’ oy") Hippuric and toluylurict acids then become respectively H? k; H H O (cH oy2° and (C2 He oy! CWO ly Care hy iE! H Formula 6 (derived from 5 by the addition of an atom of oxygen) repre- sents triatomic acids containing O°, and their derivatives. The number of substances which are certainly referable to this class is as yet very small; glycerict acid, C’ H® O* (n=3, a=0), and its homologue, C* H* O* (n=2, x=0), formed by the action of oxide of silver on a solution of bibromacetic§ acid, are examples. Formula 7 (derived from 4 by the substitution of O for H*) represents monobasic acids containing O°, and their derivatives; for instance, pyruvic acid, C* H* O* (n=3, x=0), pyromeconic acid, C’ H® O° (n=5, x=1), py- romucic acid, C’ H* O® (n=5, e=2). Formula 8 (derived from 7 by the addition of an atom of oxygen) repre- sents the important class of bibasic acids containing O*. This class includes oxalic acid and its homologues and analogues. The most recently discovered acids belonging to this group are malonic|| acid, C* H* O* (n=3,2=0), lipicq acid, C’ H® O* (n=5, x=0), anchoic** acid, C’ H’’ O* (lepargic acid, Wirz) (n=9, x=0), and insolinic}+t acid, C° H® Ot (n=9, a=4). Fumaric acid, C* H* O*(n=4,#=1,), pyrocitric acid, C’ H’ O* (n=5,a#=1), and eamphoric acid, C** H'® O* (n=10, e=1), also belong to this class. Formule 9,10, 11, 12. Substances which we can confidently refer to any * Comp. Kekulé, Ann. Chem. Pharm. civ. 141, 149; evi. 150. t+ Kraut, Ann. Chem. Pharm. xcviii. 360. t+ Debus, Ann. Chem. Pharm. evi. 79; Socoloff, ibid. 95. § Perkin and Duppa, Chem. Soc. Quart. Journ. xii. 6. || Dessaignes, Ann. Chem. Pharm. evii. 251. q Wirz, ibid. civ. 278. ** Buckton, Chem. Soc. Quart. Journ. x. 166. Tt Hofmann, ibid. ix. 210; Ann. Chem. Pharm. xevii. 197. ON THE STATE OF ORGANIC CHEMISTRY. 15 of these formule are rare. Tartronic acid, C’ H* O° (n=3, x=0), illustrates formula 9; orsellic acid, C* H® O* (n=8, e=2), formula 10 ; mesoxalic acid, C* H? O° (n=3, 2=0), formula 11 ; and aconitic acid, C° H® O° (n=6, x=1) and chelidonic acid, C’ H* O° (n=7, x=3), formula 12. By comparing these twelve formulz, it will be seen that 2 and 3 differ from 1 by containing respectively one and two atoms more oxygen, and that the same relation also exists among 4, 5, and 6; among 7, 8, and 9; and among 10, 11, and 12; and further, that 4, 7, and 11 respectively differ from 1 by the substitution of O for H*, of O° for H’, and of O° for H", and that the same relations are repeated among 2, 5, 8 and 11, and among 3, 6, 9 and 12. That is, the substances represented by the formule in the second, third, and fourth columns are oxygen substitution-products of the substances represented by the formule in the first column, and of these latter substances, the second and third are formed from the first by direct oxidation. Hence all the twelve members of the group are genetically connected with the first member. Comparing the chemical function of each with its composition and corresponding place in the group, we see that the formule in the top line re- present monatomic compounds, those in the second line diatomic compounds, and those in the third line triatomic compounds. Formula 1 represents mon- atomic alcohols, and 4, 7, and 10 monobasic acids ; formula 2 represents di- atomic alcohols, and 5, 8, and 11, diatomic* or bibasic acids; formula 3 represents triatomic alcohols, and 6, 9, and 12 triatomic or terbasic acids. From these considerations it will easily be seen how such a group might be extended so as to include tetratomic compounds, or substances in which more than six atoms hydrogen are replaced by oxygen. Such substances are hitherto so rare, that it does not seem worth while to complicate the general scheme of a chemical group by including their formule. Instances of both classes of compounds are, however, already known. Of the former class (tetratomic compounds), the following substances (which arrange themselves around an imaginary tetratomic alcohol, C H* O* (n=1, 2=0), containing the radicle (C)'’), are examples:—bichloride of carbon, C Cl’, and Hofmann’s (C° H’)’ eyantriphenyldiaminet, C* H N’= ~—-H*_s-+}- N’, obtained by its action on (C)v phenylamine ; also, in a certain sense, all cyanogen compounds, and therefore (CP Hy such substances as melaniline, C’? H N’= H* }+N*. Debus’s_ glyco- ' (C)* (Cf avd sine}, C’ H® N'=(C? H*)" +} N*, may be regarded as a tertiary tetramine de- (C’ 5 tg rived from another unknown tetratomic alcohol, C* H’ O* (n=2, x=0), homologous with the foregoing. Several saccharine substances, for instance, * Acids may be diatomic, or even triatomic, while in a strict sense they are monobasic. The acids of the glycolic series illustrate this distinction. These acids are monobasic; for they contain only one atom of hydrogen which is replaceable by metals; but at the same time they are diatomic, for they form acid amides (glycocol, &c.), chlorides containing Cl*, and intermediate chlorohydrates containing 1 atom chlorine. As Kekulé has pointed out (Lehrbuch d. organ. Chemie, 1859, p. 130), they are precisely intermediate in respect of basicity (as well as of composition) between the glycols and the acids of the oxalic series. Thus, glycol easily exchanges two atoms of hydrogen for acid-radicles, glycolic acid ex- changes one atom of hydrogen for acid-radicles (formation of benzoglycolic acid) and one atom for metals, while oxalic acid exchanges two atoms of hydrogen for metals, but none at all for acid-radicles, + Hofmann, Proc. Roy. Soc. ix. 284, t Debus, ibid. 297. 16 REPORT—1859. glucose and inannitane, have been shown by Berthelot* to have the function of polyatomic alcohols, and are probably more than triatomic. Of the latter class, meconic acid, C’ H* O", is an example: it may be regarded as deriving from an unknown triatomic alcohol, C’ H” O° (n=7, x=2), by the substitu- tion of O* for H’. Comparing together the corresponding compounds of different groups, chemists have long been accustomed to arrange them in homologous + series, or series in which there is a common difference between any two neighbour- ing terms of CH*. The discoveries of late years make it appear probable that series of similar compounds also exist in which the common difference is H*. Such series have been called isologoust. The following pairs of compounds are isologous with each other :—tritylic alcohol, C* H® O, and allylic aleohol, C’ H® O; propionic acid, C* H° O*, and acrylic acid, C* H* O?; valeric acid, C’ H*° O°, and angelic acid, C’ H® O°; caproic acid, C’ H* O?, and sorbic acid, C° H® O* (difference=2H’); sebacie acid, C’? H® O*, and camphorie acid, C’*° H’’ O*. If we confine ourselves to the comparison of bodies of the same chemical function, we can seldom find more than two or three which belong to the same isologous series; but if we compare together entire groups, we per- ceive the existence of considerable numbers of groups isologous with each other. It would be easy to render this evident by constructing a Table in which the various groups corresponding to differences in the values of m and x should be arranged so as to show at a glance their mutual relations of homology and isology ; the groups corresponding to variations in the value of n, while that of a remains constant (homologous groups), being arranged in the same vertical column; and those which correspond to the same value of n, but to various values of x (isologous groups), in the same horizontal line, or wiee versd. Gerhardt, in his ‘ Traité de Chimie Organique,’ arranges all the chemical groups, which he includes in his scheme of classification, about two primary homologous series,—the acetic series and the benzoic series. In Kekulé’s ‘Lehrbuch der organischen Chemie,’ an arrangement is adopted which is intermediate between that of Gerhardt and the classification in homologous and isologous series described above. Kekulé takes as the basis of his arrangement, the three primary series of homologous hydrocarbons, of which the first terms are— : Series I. C? H' Curr Boel ey C Re Ethylene. Propylene. Butylene. Amylene. Series II. Clay CT i? C*? H” Benzole. Toluole. Xylole. Series III. Cane Naphtaline. It will be seen that there is a common difference of C* H? between the first terms of each of these series, and that, between the terms of the three series * Ann. Chim. Phys. [3] xlvii. 297; Jahresber. viii. 678. + Schiel, Ann. Chem. Pharm. xiii. 107 (1842), first pointed out the existence of sub- stances possessing similar properties and differing in composition by C H?, or a multiple thereof. This relation was afterwards shown by Gerhardt, Précis de Chimie Organique, (1844-45), to be of very frequent occurrence, and was distinguished by him by the name * Homology.’ } The word ‘isology’ is used by Gerhardt (Traité, i. 127) in a somewhat less restricted sense. Gerhardt calls substances isologous which have the same chemical function, but which do not present the relation of homology; e.g. acetic acid, C? H*O?, and benzoic acid, C” H® 0°, a ON THE STATE OF ORGANIC CHEMISTRY. a7 which contain the same quantity of hydrogen, there is a common difference of C*. It can only be decided by the progress of discovery which of these modes of classifying chemical groups is the most accurate expression of their mutual relations. If from the point of view which we have now reached, we look back at Gerhardt’s system of types of decomposition, we see that almost all the ad- vances which have been made in theoretical chemistry, since that system was proposed, are included in the development and systematizing of the idea of polyatomic radicles, an idea, which was to some extent adopted by Ger- hardt, but which it could easily be shown was not followed out by him with perfect consistency. In conclusion of our account of the recent advances of organic chemistry, we may enumerate some of the most important reactions, or methods of transformation, which, within the last four or five years, have been shown to be applicable to the compounds of various groups, or which, from their nature, appear to be capable of such a general application. ‘They may be divided for this purpose into— (1.) Heterologous transformations, or transformations in which there is a change of chemical functions, but in which the new substances produced belong to the same chemical group as the substances from which they are formed. (II.) Homologous transformations, or transformations in which there is a passage from one group to another homologous with it. (III) Isologous transformations, or the passage from one group to another which is isologous with it. I. Heterologous transformations. Several transformations of this kind have been already referred to as enabling us to pass from monatomic to polyatomic compounds, and vice versd. We may mention further— (A) The conversion of ethylene and its homologues into the correspond- ing monatomic alcohols by combining them with acids, and the subsequent decomposition by water, or by alkaline hydrates, of the compounds thus formed* ; e.g.— C?H‘+H’?SO* = C’?H*SO* Ethylene. Ethylsulphuric acid. C’ H°+HCl sai Cl HCL Propylene. Chloride of trityl. (B) The formation of nitrogen compounds containing zinc (as zinc-amide, nitride of zinc, phenyl-zinc-amide, &c.) by the action of zinc-ethyl on the derivatives of ammoniat; e. g.— CH Zn+CH'N = C’?H'+C’H'ZnN Zinc-ethyl. Phenylamine. Hydrideof Phenyl-zinc- ethyl. amide. (C) The substitution of ethyl and methyl for chlorine in combination with phosphorus and arsenic by the action of zinc-ethyl or zinc-methyl on terchloride of phosphorus or of arsenict ; e. g— Ce ZnO P= SCP 7n4+(C* Beye. Zinc-ethyl. Teretliyl- phosphine. (D) The similar substitution of ethyl and methyl for chlorine or iodine * Berthelot, Ann. Chim. Phys. [3] xliii. 385; li. 81. t+ Frankland, Proc. Roy. Soc. viii. 502, ~ = Hofmann and Cahours, Chem. Soc. Quart. Journ. xi. 56; Ann, Chem, Pharm. civ. 1 ; Ann. Chim, Phys, [3] li. 5. ule Cc 18 REPORT—1859. in combination with mercury, lead, &c., or with the so-called organo-me- tallic compounds* ; e. g.— C’H’Zn+ClHg = C’H’Hg+ClZn. Zinc-ethyl. Mercury-ethyl. C’ H’Zn+C’ H’Hg?I = (C’H’)?Hg?+ZnI Zinc-ethy]. Iodide of Mercury-ethyl. mercurous ethyl. 3 CH Zn+CH'SnI = ©, Hf Sn+ZnI Zinc- Todide of Stanattiyl methyl. —_stanethyl. wets (E) The substitution of potassium and sodium for zine in combination with methyl or ethyl+:— 2(C?H?Zn)+Na? = 2(C?H’Na)-+Zn? Zinc-ethyl. Sodium-ethyl. (F) The formation of binoxides of organic radiclesf ; e. g.— 2(C” H’ OC1)+ Ba?O? = (C’H’O)’0*+2BaCl Chloride of benzoyl. Binoxide of benzoyl. (G) The conversion of aldehydes into the corresponding alcohols and acids by the action of alcoholic potash§; e.g.— 2C°H?O+KHO = C'H*'O+C’ H’ KO? Benzoic Benzylic Benzoate of aldehyde. alcohol. — potassium. 9C?° H*® O +KHO = (Gi H® Oo+C” H* KO? Camphor. Campholic Camphate of alcohol. potassium. (H) The formation of acediamine by the action of heat on hydrochlorate of acetamide || :— H = H cle col omy CHM ¥ H }0O Hy £0 = i! Acetamide. Acetamide. — Acediamine. Acetic acid. This reaction is interesting, as illustrating simultaneously the connexion of acetamide with the derivatives of ammonia and with the derivatives of water. Of the two atoms of acetamide which take part in the formation of acediamine, one reacts as an amide, the other as a hydrate. The following is a comparable reaction :— Cl Cl , 2) soy’ +(sory"! = (gory cre4. (80%) bor (SOY, HS", = (Soyrors GE Chlorohydrated Chlorohydrated Chlorosul- Sulphuric sulphuric acid. sulphuric acid. phuric acid. acid. (I) The action of chloride of phosphorus on amides, and the formation thereby of a new class of chloronitrides] ; e. g.— * Buckton, Proc. Roy. Soc. ix. 309; Frankland, Proce. Roy. Soc. ix. 672. T Wanklyn, Ann. Chem. Pharm. cviii. 67. { Brodie, Proc. Roy. Soe. ix. 361; Ann. Chem. Pharm. cyiii. 325. § Cannizzaro, Ann. Chem. Pharm. Ixxxviii. 129; Kraut, ibid. xcii. 66; Berthelot, Ann. Chim. Phys. [3] lvi. 79. 4 || Strecker, Ann. Chem. Pharm. ciii. 325. {| Gerhardt, Ann. Chim. Phys. [3] xlvi. 172; Iii. ; Limpri ° on thee ee ys. (3] xlvi. 1 »; lil, 302; Limpricht and V. Uslar, Aun, ON THE STATE OF ORGANIC CHEMISTRY. 19 H ie) Cl } (Cc HS)!" (CoH)! +H C14 PO CH. ag Yt Sa © Oa 2 Benzamide. Chloride of benzamidyl (Gerh.). C’ H°N?SO°+PCI® = C’H'N’?SO*CI+HCI+PO Cr Sulphobenzamide. Chloride of sulphobenzamidyl. H? . (Sulphobenzamide may be derived from the quadruple type H*?O } by 2(H°’ N) the substitution of the tetratomic radicle (C’ H*)*’ for a and the biatomic (OH 7 C’ Ht mt O radicle (SO*)" for H?; its formula then becomes n{ (Ss oy" by" . The action HH of chloride of phosphorus upon it is to replace the H* O of the type by HCl; the product of this action may be written HCl (eee } APS (C Ht) t HH ype w {ts o"y" by? N {HH }N.) HH (K) The formation of aldehydes from their corresponding acids by distill- ing their alkaline salts mixed with an alkaline formate* ; e. g— Un KROTCAKO => UH OSCR O Benzoateof Formate of Benzoic Carbonate of potassium. potassium. aldehyde. potassium, (L) The substitution of hydrogen for compound radicles contained in organic bases ; ¢. g.— CH’ . H CHS‘N+HO = CH YNICHO CAH’ C? H’ Phenylic Diethylphenylamine. Diethylamine. alcohol. H H ) C?H’+}N+H?O = H $+C?H°O C’ H° CH Alcohol. Diethylamine. Ethylamine. H a H H >N+H’*?O = H >N+C’?H*°O Cin) H Alcohol. Ethylamine. II. Homologous transformations. (A) The combination of carbonic anhydride with the compounds of in alcohol radicles with alkali-metalst; e.g.— * Piria, Ann. Chim. Phys. [3] xviii. 113 ; Ann. Chem. Pharm. c. 104; Limpricht, Ann. Chem. Pharm. xevii. 368; Amn. Chim. Phys. [3] xlviii. 118. + Matthiessen, Proc. Roy. Soc. ix. 118, 635. } Wanklyn, Ann. Chem. Pharm. cvii. 125; exi. 234; Ann. Chim. Phys. [3] liii. 42. The above reaction corresponds closely with that of sulphurous anhydride on zinc-methyl :— CH? Zn+S0? = CH? ZnSO? Zinc-methyl. Methylodithionate of zinc. Hobson, Chem. Soc. Quart. Journ. x. 243; Ann, Chem. Pharm. evi. 287. : c2 20 REPORT—1859, CH? Na+ CO? = C? H* NaO? Sodium-methyl. Acetate of sodium. (B) The supposed formation of methyl compounds from acetone* ; e.g.— CHO+0 = CHO Acetone. Acetate of methyl. (C) The formation of complex hydrocarbons (ethylene, propylene, amy- lene, benzine, naphtaline, &c., by the action of heat on organic substances of simpler constitution. Synthesis of organic compounds). Ill. Lsologous transformations. (A) The conversion of glycerine into iodopropylene, and of the latter into allylic alcohol { :— 9(C? H°1)+Ag?C? 0! = 2AgI+(C* H*)?C? Ot Iodopropylene. Oxalate of Oxalate of allyl. silver. (C? H’)? C2 O'4-2N H® = 2C?H*0+C?H!* N? 0? Oxalate of allyl. Allylic Oxamide. alcohol. (B) The production of cinnamie aldehyde from acetic and benzoic alde- hydes§ :— C? H‘O+C’ H°O=C’ H*0+H’O Acetic alde- Benzoic Cinnamic hyde. aldehyde. aldehyde. (C) The production of cinnamic acid from chloride of acetyl and benzoic aldehyde || :— C? H*OCI+C’ H*O=C?’ H*0’+ HCI. Chloracetyl. Benzoic Cinnamic aldehyde. acid. Throughout the foregoing Report Gerhardt’s atomic weights have been used without discussion; for it seemed superfluous to enumerate once more the reasons for adopting them, which, as the science advances, become more and more numerous and conclusive§. It may, however, be expected that some notice should be taken of such objections as have been recently made against this system. Within the last few years three different chemists have, for very different reasons, proposed to modify Gerhardt’s atomic weights, but they all agree in adopting the doubled atomic weight of carbon, while they reject the doubled ® Friedel, Ann. Chem. Pharm. cvii. 174; cviii. 388. + Berthelot, Ann. Chim. Phys. [3] liii. 69. + Hofmann and Cahours, Chem. Soc. Quart. Journ, x. 316; Ann. Chem, Pharm. cii. 285 ; Ann. Chim. Phys. [3] 1. 432. § Chiozza, Ann. Chem. Pharm. xevii. 350. || Bertagnini, Ann. Chim. Phys. [3] xlix. 376. J Some recent experiments nevertheless tend to show that the atomic weights assigned by Gerhardt to some of the metals ought to be doubled. For instance, the vapour-density of zinc-ethyl (Frankland, Ann. Chem. Pharm. xcv.), the way in which zinc combines with iodide of ethyl (similar to the combination of oxygen with zinc-ethyl, Zn?+-C? H5 [= C? H® Zn21, and O+4-C? H5 Zn=C? H5O Zn), the vapour-density of mercury-methyl and of mer- cury-ethyl (Buckton, Proc. Roy. Soc. ix. 92, 311), and the combination of mercury with ~iodide of ethyl (forming C? H® Hg? 1), seem to show that the atomic weights of zinc and mer- cury are twice as great as they were adopted by Gerhardt. Similar reasons may be urged in favour of doubling the atomic weight of tin, as recommended some time since by Odling (Phil. Mag. [4] xiii. 434). As these points, however, belong to inorganic chemistry, we cannot do more than simply refer to them here. ON THE STATE OF ORGANIC CHEMISTRY. 21 atomic weight of oxygen: we refer to Limpricht*, Kolbey, and Coupert. The first of these chemists founds his objection to the greater atomic weight of oxygen upon the fact that some salts crystallize with a quantity of water containing an odd multiple of 8 parts of oxygen. To this it may be answered, that the function of water in crystallized salts is not sufficiently well understood to warrant our drawing conclusions of any importance from the quantity of it contained in any particular substance, and that no reason has yet been shown why several atoms of a salt should not crystallize with one atomof water, as well as several atoms of water with one atom of a salt. The objections of Kolbe are founded on more general considerations. By comparing the composition of the so-called organo-metallic bodies with that of the inorganic compounds of the metals which they contain, he came to the conclusion that the metallic oxides are typical of the compounds of the metals with organic radicles. For instance, taking the atomic weight of oxygen at 8, and writing oxide of zinc and arsenious anhydride ZnO and AsO?’ respectively, we get the following comparison of formula :— Oxide of zinc ZnO Arsenious anhydride As O° Zine-ethyl .. ZnEt=ZnC’ H’ | Oxide of arsenomo- nomethyl ...... AsO? Me = As0*CH® Oxide of kakodyl.. AsO Me*’= As OC*H® Termethylarsine .. AsMe* =AsC*’H’. Admitting the accuracy of such formule, it was natural to extend similar views to those compounds of carbon which do not contain metals. Accord- ingly, Kolbe regards carbonic anhydride C 0*, the highest known oxide of carbon, as the type of a large number of other carbon-compounds. Accord- ing to him, the replacement of 1 atom oxygen in carbonic anhydride by 1 atom hydrogen, or ] atom of an alcohol-radicle, gives monobasic acids, such as those of the acetic and benzoic series ; the like replacement of 2 atoms oxy- gen gives aldehydes and acetones ; the replacement of 3 atoms oxygen gives ethers; and lastly, the replacement of all the oxygen gives alcohol-radicles and their hydrides. The following illustrations will make this clearer :— O Type.. C} @ O I. Il. IL. IV. H CH* H CH H H H H O O C H* CH* H H H H C19°) of ©} 0 ©) o | ©) 8 ©) cH] o)H ©) B O O O O O O H C H® Formic Aceticacid Aldehyde. Acetone. Methylic Ether. Hydrideof Methyl. acid (anhydrous). ether. methyl. (anhy- drous). It must certainly be considered fortunate for the interests of science that Professor Kolbe should himself have extended his theory to the purely organic compounds of carbon; for these being the precise substances of * Limpricht, Grundriss der organischen Chemie (1855). + Ann. Chem. Pharm. ci. 257. The same views were also advocated by Frankland in a lecture delivered at the Royal Institution, May 28th, 1858. (See Journ. Roy. Instit.) t Ann. Chim. Phys. [3] iii, 469; Ann. Chem. Pharm. cx. 46. 22 REPORT—1859. which our knowledge is the most complete, the application of the theory to them makes it possible to arrive at a more certain conclusion as to its value, than would be the case were it confined to the substances to which it was originally applied. Respecting the above and similar formule, it may he observed,— ‘ : 1. That, leaving out of view the substances under discussion, there is no reason to believe that the oxygen in carbonic-anhydride can be divided into more than two parts; there is no evidence that carbonic anhydride contains more than two atoms of oxygen. 2. That there is no similarity, nor definite gradational difference of proper- ties, between the type C O* and the substances represented as deriving from it. 3. Two out of the four formule given above, namely the first and third, are in direct opposition to Gerhardt’s atomic weights; we know, however, that they represent only half an atom of the bodies to which they are assigned. Views respecting the nature of chemical affinity have induced Couper to adopt 8 as the atomic weight of oxygen. He, however, finds that, owing to a peculiar tendeney which oxygen possesses to combine with oxygen, the smallest quantity of it which ever enters into combination is twice 8. This being admitted, it seems a matter of minor importance whether the smallest combining proportion of oxygen should be represented by the symbol O=16, or by the symbol O°=16. September 10, 1859. Report on the Growth of Plants in the Garden of the Royal Agricultural College, Cirencester. By James Buckman, F.S.4., F_L.S., F.G.S., &c., Professor of Natural History, Royal Agricultural College. Tue following notes are upon experiments which have been completed or are still.in progress in the experimental garden of the Royal Agricultural College, and this Report is furnished at the instance of the Natural History Section, the experiments having been made the subject of a grant from the funds of the British Association. It is hoped that the present Report will show the desirability of continuing experiments upon plants, as whatever effect they may have upon our theore- tical views, I think it will clearly be seen that many practical matters of great importance are involved in inquiries of this kind, and I shall therefore not detain the Section with any lengthened introduction, but at once ask for a kind and considerate attention to the following notes :— The cultivation of flax or lintseed offers such interesting matter to the na- turalist, as being of importance in an economic and agricultural point of view, that we cannot help detailing some experiments connected therewith. Plot A was sown in drills with a pure sample of linseed grown on the farm of the Royal Agricultural College. : Plot B was sown with a like weight of seed uncleaned, it therefore con- sisted of full half its weight of weed-seeds. : Plot C was sown with a like weight of pure seed as in plot A, to which was afterwards added a good sprinkling of dodder-seed, viz. Cuscuta epilinum. These beds were left unmolested, not even being weeded. The seed became ripe in the middle of August, at which time the following observa- tions were noted upon each of them :— ON THE GROWTH OF PLANTS. 23 Average height |___Pr0Portionals in inches. of fibre. hacks Plot A. Regular in the rows, and clear of weeds . . 36 50 50 Plot B. Irregular, flax sparse, weeds plentiful. . . . 34 20 25 Plot C. Borne down to the ground with dodder, and most of the flax stems rotting. ......-+... 32 15 20 Hence, then, in as far as the economics of the question are concerned, we may safely conclude that the sowing of dirty flax-seed at any price is disad- vantageous, and this not only that the resulting crop, if not quite ruined, is certain to be diminished in quantity and injured in quality, but, as ill weeds grow apace, all the sorts growing with the flax had sown much of their seeds before the flax-seed itself had ripened, so that a succession of weeds is by this means entailed upon the farm from generation to generation. As regards the plot with dodder, the object of sowing these together was for the purpose of observing with my Class the manner in which the parasite became attached to its foster-parent, and I therefore offer the following remarks upon the growth of the Cuseuta epilinum, not as containing any new results, but as offering an example of the kind of experiments followed out in my botanical garden. In about four days after the seed of the dodder was sown, a few whitish thread-like germs of about Fig. 1. Fig. 2. Fig. 3. three lines in length were q seen protruding from the . As ’ soil, some of these being quite free, others crowned \/ with the seed testa. Three days afterwards the flax came up, and the dodder Va might then have been seen, f as in the accompanying y, f fig. 1, bending its germ g towards a flax-plant; by this time it has doubled in length; and if the flax- \ I plant be far away, it seems 7 to be endowed with the power of growing to as much as an inch in length in order to reach it, whilst in experiments of dodder seed sown by itself, the germs were always short | | PAA; and soon withered; but on inserting other plants in the same pot, they became i attached tothem,as Radish, __eeph beg a be ES Tomato, Groundsel, and 9 °°" pene Chickweed were all in this way attacked by the dodder amongst which young plants were inserted; and in one case, where a pot of growing flax dodder was placed near a Sedum in my conservatory, the latter was attacked, and the dodder grew upon it most vigorously. In a short time after the germination of the dodder and the flax, the 24 REPORT—1859. former reaches the latter, when it makes one or two coils round the flax stem, as shown in fig. 2, when immediately small cells begin to develope themselves inside the dodder coils ; these form aérial roots which soon penetrate the flax, which is now growing in size and height. It is now incorporated with the circulation of the foster-parent ; its own radicle is no longer required in con- nexion with the soil, and so the whole dodder plant is elevated by the flax, as shown in fig. 3. When this attachment is completed it pushes forth new fibres, each of which behaves like the parent germinal fibre Fig. 4. and attacks any plant growing near, so that j we need not wonder at clusters of dodder rapidly advancing in the flax crop where it is sown. Our fig. 4 represents the advance in growth of a single dodder plant ve days after its attachment. Plot D.—This is Linum perenne, before reported upon; it still keeps up its character, and is a fine upright perennial flax bearing one large and a second smaller crop of stems annually ; however, from thus overgrowing, the plants are gradually wearing out. Plot E is from the seed of the above; it has the same appearance, but is not yet so vigorous and tall in growth. Seed is sowed from this to carry on experiments. Plot F. Rosa spinosissima (L.). Plot G. Rosa Doniana (Woods). I procured specimens of these two forms of Rose from the neighbourhood of Worces- ter, in December 1857, having been taken to their localities by my friend Mr. Edwin Lees. The habitats of both these are much alike, being on the margins of the old Severn Straits, and they serve to mark the former marine conditions which pertained until com- paratively lately along the course of the Severn into the Midland Counties. Several specimens were forwarded to my gardener and planted in a prepared border, and at the present moment they present such a uniformity of appearance and habit, with true place of FR. Doniana is with the Rosa villosa, an arrangement, if admitted, which will go far in my opinion to reduce most of the species (of authors) of this genus which we have in England to the inferior rank of varieties, a conclusion which I have no doubt would be justified to a much greater extent than even the “lumping” botanist is prepared for with care- ful growth fiom seed, and we are hence collecting rose seeds for experiment, in which we ask the aid of botanists for the rose forms of their localities. Plot H. Viola odoruta.— All the roots in this plot turned out this year to be ON THE GROWTH OF PLANTS. 25 the lilac variety of V. odorata, much to the astonishment of my gardener who planted most of them for V. hirta; however, as these were not planted under my own superintendence, I cannot answer for the results, though I quite think that Mr. Bentham’s remarks under the head of V. hirta, are not without foundation; they are as follows :—“ Hairy Violet, Viola hirta, Linn. Very near the sweet violet, and most probably a mere variety.” This seems confirmed by the immense varieties on the Great Oolites and the Forest Marble clays of this district, presented by both odorata and hirta. These then are reserved as subjects for future experiment, to which end a quantity of seeds are collected. Plot I. Myosotis.—Some years since I was charmed with the appearance of a tuft of Myosotis which I saw at my nurseryman’s, since which time I have always had some of it in cultivation as early spring flower. My specimens were allowed to seed on the ground, and the young plants are shifted about when required for garden decoration, Now it is remarkable that the original roots are perfectly perennial, but the seedlings at best are only sub-perennial. In most the seed comes up the same summer that it has been scattered, and flowers, seeds and dies the next spring, which indeed is precisely the habit of Myosotis arvensis ; and hence | conclude that the original plants, if pro- pagated by slips, the usual gardeners’ method, would be the M. sylvatica of authors, the seedling the large-flowered form of M. arvensis. In other words, I think these experiments tend to show that these two supposed species are but varieties, an idea indeed which Sir W. Hooker seems to favour in the 5th edition of his ‘ British Flora.’ In as far as my experiments have progressed with these plants, I am induced to adopt Mr. Bentham’s view, that the M. alpestris (Schmidt) is the larger flowered form of M. sylvatica; for as the old stock of our favourite seemed to be diminishing in the size and intensity of the colour of its flowers, I have this year introduced some M. alpestris from a friend’s garden, and I fully expect the seedlings of this to take on the following declension :— M. palustris? (perennial). M. alpestris (perennial). M. sylvatica (sub-perennial and annual). M. arvensis, fl. maxima (annual). M. arvensis, fl. minor (annual). Of the three last of these descents I am perfectly clear, and Mr. Bentham, under the Myosotis sylvatica, has the following remarks :—“ It varies much in size and stature; in lower shady situations, and in our gardens, the stems will attain a foot or more in length with rather small flowers. The alpine form, with larger flowers, is by some distinguished as a species under the name of M. alpestris*.’—Handbook, p. 377. In this genus then we may expect to find some interesting results from experiments, as a further contribution to which end I hope to get seeds of the M. palustris for garden culture, some experiments of this kind in a garden I have left inclining me to think this water form as not so distinct from the terrestrial ones as some may think. Plot J. Datura Tatula, Purple Thorn-Apple.—The crop of this season is from seed supplied by Butler of Covent Garden; it is at least twice the size of that which was previously reported upon, and the flowers and whole plant * This view is also shared by Mr. Babington. 26 REPORT—1859. appear to be unusually dark in colour, in which it contrasts finely with the following. Plot K. Datura Stramonium, American Thorn-Apple.—Only three plants have this year arrived at maturity, but its extreme whiteness is quite re- markable when placed beside the D. Tatula, a crop, which, it will be remem- bered, was formerly reported a ie almost destitute of colour. Plot L. Dipsacus sylvestris (L. " pee ete it mnlaetls These, though distinguished by Linnzus and retained as species by Smith and Hooker, are shown by my garden experiments to be but varieties; in- deed, Sir W. Hooker, in speaking of the reflexed scales, says, “ These hooks become obsolete by long cultivation in poor soil, and there is reason to believe that D.fullonum is but a variety of D. sylvestris.” In this he has been followed by other authors; as yet I am not aware of any direct obser- vations upon the point, but my experiments upon the two forms enable me to supply this. In 1857 I had a plot each of Dipsacus sylvestris and D. fullonum flower- ing, and at last ripening their seed side by side. ‘This seed became scat- tered about the garden, and not having a distinct plot of teasels for botanical illustration, a plot was made of the most vigorous plants which could be selected from the self-sown examples without an attempt to discriminate the different sorts, which indeed would have been impossible at this stage of growth. Now the result at the time of my writing is very striking; there are the true D. sylvestris with the straight scales, the D. fullonum with the stiff reflexed hooks, and all intermediate stages, so that it is most difficult to separate them, if indeed they are to be distinguished. In order, therefore, to keep up the fulling apparatus of the teasel in perfection, it is important that the plants be cultivated, as, letting them go wild, they revert to the use- less form ; and strong land is also necessary to the growth of stiff hooks. Plot M. Carduus tuberosus.—This plant, which I was fortunate enough to discover in North Wilts, about the Avebury Circles, is the same as was recorded some five-and-twenty years since, as existing at Great Ridge in the south of that county, It has fora long time been lost to our flora, though a few specimens were still in cultivation in the garden of my friend Mr. Cun- nington of Devizes. ; In August 1857 I brought home a few plants from Avebury, which made some new shoots last year, but did not flower; they, however, had the cha- racteristic tubers of a good size. These were parted, and now occupy the plot as above. As now seen in their wild habitat, the flower-stem is scarcely above a foot high, with from two to four flowers each. In cultivation it has attained the height of 3 feet, with a large mass of stems to each plant, bearing from six to twelve flower-heads each: the flowers are very showy, and, like the tubers, increase in size under cultivation. As this plant yields these tubers so abundantly, I boiled some of them to ascertain if they were edible; and as they are made up of feculent matter which proves to be tender and sweet to the taste, I am not quite sure that this thistle might not be cultivated as a vegetable to advantage. Seeds of the plant have been saved for the purpose of experiment, as I have not yet given up the idea of the hybridity of the Carduus tuberosus ; and, with all its large flowers, I may observe that it seeds only sparingly. Plot N. Carduus acaulis——By the side of the above are two varieties of this plant occupying the same plot; one the normal stemless form, another with stems as much as 2 feet high, each of which bears from four to eight ON THE GROWTH OF PLANTS. 27 heads of flowers. Mr. Bentham, in his ‘ Handbook of the British Flora,’ has the following remark under the head of Carduus acaulis :—“ In some situa- tions on the continent, the stem will grow out to 6 or 8 inches; but this variety is very rare in England.” It is, however, common on the Cotteswolds, with stems a few inches in length, and, as we have seen, this increases very much under cultivation. Plots O and P. Yellow Globe Mangel Wurzel.--The question is often asked us by farmers and others, as to whether the leaves of this plant cannot be used for feeding purposes, and so be plucked off from time to time as the root is growing without prejudicing the amount of root-growth. Of these plots, then, one has had all the external leaves removed twice during the present season, and will be so served once more, the plot being left intact. Already there is an immense difference in the size of the roots, those on the stripped plot being at present not more than half the size of the others*. In reference to this subject, I may refer to a like experiment which I carried out in my garden in 1854. ‘Two plots of each of five sorts of mangel wur- zel were sown side by side. Of these a plot of each was denuded of leaves in the manner just indicated, the rest being left uninjured, and the following Table will give the result :— Table of Growth of Mangel Wurzel. Proportionals. Sorts. ss Not stripped of outer leaves. | Stripped of outer leaves. ee —— Red globe. .-+---+> 31:0 235 Yellow globe ...+..-- 45:0 18°5 Longred .......-- 49-0 180 Long yellow .....+-- 35°5 180 Long white .......- 32°5 19°5 Total .. 193°0 97°5 Here then it will be seen that the poorer the crop the less the injury done to the leaves. Plot Q. Indian Rape.—Some seed so called, obtained from a seedsman, was sown in April in drills, but not a single specimen germinated, I have, how- ever, been more successful with a sample obtained from a seed-crusher, as four-fifths came up, and my samples are progressing towards maturity, although not yet sufficiently far advanced to enable me to determine the now important question of —What is Indian Rape? First, then, in order to bespeak attention to this matter, it will be well shortly to review its points of interest; of these the following extract from a trade circular will shortly explain one :— ' “TJ have sold this day some India rape-seed for mixing with turnip-seed, and enclose asample. If you will have some at 56s. per quarter in the docks, you can have it, if unsold, to your answer.” This, be it remembered, to mia with turnip-seed, which is sold at from 9d. to 1s, per lb., a quarter being probably as much as 500 Ibs.—a good margin for profit ! Drikes phase of the subject will be found in the Report of the Trial of Greville versus Briggs, at the late Wells Assizes, in which damages were * This experiment gave the following results :— lb. oz. Plot O. Leaves removed, 21 plants weighed ........:sseserssseereee 24 44 Plot P. Leaves intact, 20 plants weighed ...cccsecccseseeeeeeees 28 REPORT— 1859. sought and obtained for some cattle that were proved to have been poisoned by rape-cake, the defence being that the cake in question was made from Indian rape. Now it would appear that very large quantities of this seed are sold annu- ally, partly to the seedsman, but more to the seed-crusher; the former mixes it with turnip-seed to adulterate it,—carefully preparing it, however, to pre- vent germination, as in our turnip-drilling age, a false plant would be detected in the rows*. The seed-crusher mixes it with true rape in crushing for rape-oil, and so the resulting cake appears to get poisonous properties in proportion to the quantity of “Indian rape” present, the truth being that this seed has all the properties of Sinapis arvensis—charlock mustard, which acts as an irri- tant poison to the cattle. Now, although we are not quite certain as to the specific identity of our Indian rape plants, we incline to the notion that it is, if not true Sinapis arvensis, as we know it in this country, a variety of this plant; but upon this I shall be enabled to report more at length in another season. Plot R. Brassica oleracea.—I this year gathered seeds of this wild cabbage from Llandudno, N. Wales, and I have some just germinated; upon these I hope to carry on a series of experiments for some years to come, with the object of tracing the production of the well-marked varieties which this plant is capable of producing. Plot S. Trigonella Fanum-grecum.—The Fenugreek, as a plant which is likely soon to occupy a great deal of attention, has formed a subject for experiment, the object being to ascertain if this eastern plant would perfect its seed in this country. My plot is now in full growth, and its abundance of long-pointed legumes, full of all but ripened seeds, are satisfactory as to the capabilities of the plant for cultivation in even exposed situations. Fenugreek is now being extensively used as a flavouring ingredient for the so-called ‘‘ Concentrated Cattle Foods ;” and though the notion of food being concentrated by the addition of this plant is proved to be a fallacy, yet I think there can be little doubt that even inferior pulse or grain may be made more palatable by a flavouring principle; and it is a question of as great importance to the well-being of our domestic animals as to ourselves, whether nutrition is not increased by flavour. The whole plant, but especially the seeds of the Fenugreek, contains a chemical principle which has been named “ Cumarin,” which is described as follows :— * Cumarin, C,,H, O,, is found in Tonka Beans, in which it sometimes appears in the shape of crystals; in the flowers and whole plant of Meli/otus ; in Asperula odorata and Anthoxanthum odoratum, and probably in other aromatic plants.’—Schlossberger’s ‘Organic Chemistry.’ Fenugreek is highly flavoured with cumarin; and as the presence of this in some grasses, especially in Anthoxanthwm odoratum, is the cause of a good flavour to hay, and for which horses always smell so carefully before eating, there is every reason to believe that this principle is being extended to other cattle foods, and in consequence the use of Fenugreek is rapidly extending. Cattle-food manufacturers are starting up in every district, and with all of them this plant is employed as the flavouring ingredient ; and it would appear at a great profit; as food, which before mixing would be about £7 per ton, is * Tn reference to this I may say that in Wales drilling of turnips is almost unknown, so that preparation of false seed is not required, as these simply get looked upon as weeds “natural to the soil;” but I saw the other day a patch of Swedes which had been drilled, and I counted 96 plants of Charlock, and 4 only! of Swedes to each hundred in the rows. ON THE GROWTH OF PLANTS. 29 increased to a charge of somewhere about £42 per ton. Now if the system of flavouring cattle food be found to answer and the principles just enun- ciated are found to be correct, there need only be an addition of a few shillings per ton as the cost of rendering cattle food more palatable and so easier of digestion, and consequently of a higher nutritive value. I am informed that the seeds have recently doubled in price in consequence of their extended use ; but the experiment has shown that we can, if required, grow it in this country. Plots T, U, and V are occupied with vetches derived from the Vicia angus- tifolia. T. V. angustifolia, var. sativa. Spring crop. . wv. 33 var. sativa. Winter crop. Vv. V. rr formerly var. sativa, but being left wild as a perma- nent crop, is again reverting to its wild form. The facility with which wild vetches can be cultivated into new forms and of exceeding rank growth is a matter fully settled by these experiments, and they take so short a time to bring about, that they can be easily repeated by any one. Plot W. Scorzonera. Plot X. Salsafy. These were both drilled from old seed, and their paucity of plants offers good instruction in relation to this subject. In an agricultural point of view, nothing can be considered more objectionable than want of care in this respect. Though these are plants of the same family, there has been a great difference in the germination of their five-year old seed. Of Scorzonera came up about 2 per cent. OF Salsafy came up about 10 per cent. The plants, however, look well and healthy. These are amongst the good vegetables which the comparatively flavour- less and innutritious potato has displaced. Plot Y. Dioscorea Batatas, Potato Yam.—These plants have this year been elevated on high ridges, but do not grow vigorously in the exposed experimental garden. However, in my own private garden in the town, whieh is surrounded by high walls and well-sheltered, my crop promises to be better than usual, and I shall look forward to the produce with some interest. Plot Z. Tamus communis, Black Bryony, as being an allied plant, is now the subject of experiment. This year’s crop is from seed sown last summer ; they are a little larger in the tuber than peas. These will soon be taken up and stored for plantation in the same manner as the preceding; whether the feculent black bryony root can be made edible remains to be proved Plot A’. Parsnips in seed.—This is a plot of my ennobled wild parsnips, experiments connected with which were reported upon in 1856. The last year’s experimental plot was so fine that the whole of it was left for seed ; while Plot A? is a large piece of parsnips in the kitchen garden from my seed of 1856: here the new parsnips promise to be very large and clean in the skin, the College gardener now preferring it to any other kind, as this new offspring of the insignificant wild root is much richer in flavour than the older varieties, which are wearing out in this respect. My roots now offer examples both of “long horn” and “short horn” varieties, so that another year I shall be enabled to save seed of two distinct and newly induced varieties. GrassEs.—The experimental plots of grasses which have been already 30 REPORT—1859. reported upon, maintain their induced characters most perfectly, and I have become still more convinced of the little value to be placed in the specific characters of these plants as laid down by botanists, while at the same time Iam fully aware how easy it is to make permanent varieties. In experiment- ing upon these, however, it must be admitted that there are great difficulties in the way, arising from the facility with which they become mixed with one another, and altogether the trouble there is in keeping the plots clean; still the changes in Oats and in the Poa aquatica cannot be vitiated on this account, as their descendants are not like anything around them; the Poa, indeed, is altogether new; we have no grass in the British Flora at all like the speci- mens I now submit to the Section. This is, in fact, as much a new and distinct species as the most specific of our well-known forms, and yet its production is perfectly under control, and that not, as has been hinted, as an isolated specimen, but in whole patches. Plots B' and C’ are of this descendant from Poa aquatica, and fine grasses they are; they have already been laid before the Section, with the seeds whence they were derived in 1857; but these experiments, and all upon the grasses, will be again repeated on a new patch of ground which is clearing for the purpose; and if I can but get good seeds, I anticipate a great deal of new matter from this source. Plot D* is Poa aquatica from plants taken from the canal side; they are growing very well; but even from growing in an unaccustomed habitat, they are taking on immense differences, which I expect time will confirm; I shall therefore reserve any further description of this until auother opportunity. Plots D‘, E*, F’, were devoted to oat experiments as follows :— D'. Avena fatua, var. sativa. 'Tartarean sort. E*. Avena fatua, var. sativa. Potato sort. F'. Avena fatua, formerly sativa. Left wild as a permanent crop. Of these, D’ and E* have maintained their characters both in my experimental plots and in the extended farm cultivation to which they have been subjected by Mr. Coleman, the Manager of the Royal Agricultural College Farm. Plot F’ has presented all phases of reversion, just as may be observed in the field on examining the offspring of ‘ shed’ oats. Plot G* is occupied with a grass which has recently excited some attention, it is the Holeus (Sorghum) saccharatus: its seed was drilled early in April, and duly thinned out as it advanced. Early in August it had stooled to about five culms to each plant, of which the main or primitive one was the largest ; at this time I gathered some in order to try how the cows liked it; but they uniformly refused it, which was not to be wondered at, when at this time the whole of my plants possessed an intensely bitter taste. On the Ist of September I again made trial with some of the more advanced shoots; they were devoured greedily, but now an immense quantity of sugar had been developed, as the bases of these tasted quite as sweet as liquorice root. This points to the cireumstances that the juices of this plant may be rich in saccharine matter at a later, though not at an earlier stage of growth; if, then, it is ever to be useful as a feeding grass, this must be attended to; but I much doubt whether at any time in the cold climate of the Cotteswolds this species of sugar-cane will yield so much sugar as in a warmer and less ‘exposed position ; at the same time, as a first trial, I consider this eminently successful, and I should not wonder to see it more fully tried over a great part of England next season. ON THE ESSENTIAL CONSTITUENTS OF MANURES. 31 Report on Field Experiments and Laboratory Researches on the Con- stituents of Manures essential to cullivated Crops. By Dr.Augustus VortcKker, Royal Agricultural College, Cirencester. Tue field experiments on which I have to report were begun in 1855, and have been continued since from year to year. They were at first instituted chiefly for the purpose of ascertaining practically the comparative economic value of some of the artificial manures, such as guano, superphosphate of lime, bone-dust, &c., in reference to root-crops. In the course of my experiments, however, I was led to abandon, more or less, the primary object for which the experiments were at first undertaken, and to make them subservient to assist the solution of several disputed and important points in agricultural and physiological science. Amongst other questions which arise in the mind of the agricultural chemist who has closely followed the progress of agricultural chemistry, the following are some of the more important :— 1. Can ammonia or nitrogenized matters be dispensed with in manures, or is it desirable that there should be a certain proportion of nitrogenized matter or ammonia in manures ? 2. What is the effect of ammoniacal salts, of phosphates, of alkalies, and other fertilizing constituents applied separately upon vegetation ? 3. Is the practical effect produced by ammonia, or by phosphates, &c., the same upon wheat or other grain crops as that produced upon turnips or clover? 4, Are there fertilizing constituents which benefit certain crops more than others ? 5. Is it desirable or unphilosophical, and therefore leading to the ultimate exhaustion of the soil, to apply special fertilizing matters to the land, i.e. matters which contain but 1, 2, or at all events a limited number of chemical compounds ? or is it necessary, in order to maintain the permanent fertility of the land, to restore to the soil in the shape of a compound and universal ma nure, all the constituents removed by the crops grown upon the land in pre- vious years? These and other similar questions, affecting agricultural practice, have occupied me for several years past. The results of my experiments detailed in the following Report, I trust will be found useful contributions towards the final settlement of the mooted questions. Field Experiments made in 1855. _ Although I believe that the minute chemical analysis of soils, generally speaking, affords but little or no indication as to the fertilizing matters which are best calculated to improve their productive powers, I am still of opinion that it is desirable and even indispensable to record in all field experiments, the principal physical characters, and the amount of at least the chief or pre- ponderating constituents of the soil of the experimental field. I would therefore observe that the experimental field was a naturally poor shallow soil with clayey subsoil of inconsiderable depth, and resting on the Great Oolite limestone rock. Submitted to a general analysis, it yielded— Organic matter and water of combination.............- 6°339 Oxides of iron and alumina, with traces of phosphoric acid 9°311 Carbonate of lime ............ ren ree seeee 54°566 Magnesia Alkalies determined by loss........... eineeye "837 Sulphuric acid Insoluble siliceous matter (chiefly clay) .....+..+e++++ 28°947 100000 32 REPORT—1859. The land was left unmanured in the preceding year, and was considered a poor turnip soil. Hs Tite ; I purposely selected a poor field ; for it strikes me on such a soil the ma- nurial effect of different fertilizers is much better discerned than on land in a high state of fertility. The productive power of soils cannot be increased to an unlimited extent; and when by good cultivation it approaches its maxi- mum state of fertility, the addition of the most effective fertilizing matters cannot produce any marked effect. I may, however, observe that care was bestowed upon the mechanical preparation of the land, which is not always done in field experiments. The experimental field was divided into ten different plots of one-eighth of an acre each. These plots were arranged side by side in continuous rows of drills, care being taken to reject the headlands. The different manures were all applied to the land on the same day, and the Swedish turnip-seed sown by a ridge-drill on the 20th of June. Subsequently all the plots were treated in precisely the same way, and care was taken to render the experiments in every respect comparative. One of the plots was left unmanured, the nine remaining were manured as follows :— Plot 1 received 56 Ibs. of Peruvian guano, or at the rate of 4 cwt. per acre. Plot 2 received 84 lbs. of Suffolk coprolites, treated with one-third their weight of sulphuric acid ard 28 lbs. of guano, or at the rate of 6 cwt. of dissolved coprolites and 2 cwt. of Peruvian guano per acre. Plot 3 received 100 Ibs. of bone-dust, or 7 cwt. 16 lbs. per acre. Plot 4 received 93 Ibs. of bone-dust dissolved in one-third its weight of sulphuric acid, or at the rate of 6 cwt. 72 Ibs. per acre. Plot 5 received 56 lbs. of economical manure, or at the rate of 4 ewt. per acre. Plot 6 received 120 lbs. of nut-cake, or at the rate of 8 cwt. 64 Ibs. per acre. Plot 7 was manured with 140 lbs. of dissolved coprolites, or at the rate of 10 ewt. per acre. Plot 8 was left unmanured. Plot 9 received 180 lbs. of commercial night-soil manure, or at the rate of 12 cwt. 96 lbs. per acre. Plot 10 was manured with a mixture of 1 bushel of soot, 30 lbs. of guano, and dissolved coprolites and dissolved bones. The respective quantities of these fertilizing matters were all obtained at the same cost of 5s. per plot, or at the rate of £2 per acre. All the different fertilizers were carefully analysed; but in order not to swell too much this Report I abstain from giving the details of the analyses. I may; however, observe that the guano contained 14°177 per cent. of nitro- gen, and 25:06 of bone-earth, and nearly 3 per cent. of phosphoric acid in combination with alkalies. We have thus in Plot 1 a manure contain- ing a large proportion of nitrogenized matters as well as phosphates and alkalies. In Plot 2 only half the amount of guano was used, and phosphates more largely supplied in the shape of dissolved coprolites. The coprolites, however, having been treated with only one-third their weight of acid, contained scarcely more than 6 per cent. of soluble phosphates; and it is to be feared that the remainder of the undissolved phosphates in the coprolites exercised little or no effect upon the turnip-crop. _ In Plot 3 we have a manure which contains 44°22 of insoluble phosphate of lime, and 4°28 per cent. of nitrogen. ON THE ESSENTIAL CONSTITUENTS OF MANURES. 33 In Plot 4 bone-dust dissolved in one-third its weight of sulphuric acid, consequently a manurewhich contained both soluble and insoluble phosphates, was employed. The economical manure, a manure highly recommended for the growth of root-crops, and used upon Plot 5, contained in 100 parts— UV eat eaten APRS. Sov tec nisla al oinsidi.e eed 86°525 Protosulphate of iron ...... Beeewa oO (OU Sulphate of lime .....ccesesscees 860 Sulphate of magnesia ,.......++4 204 Bisulphate of potash........00+--. 4677 Bisulphate of soda.,.......++.++++ 10°928 Sulphate of soda ........ee0e.+++ 15°143 Sulphate of ammonia........... coe) «2648 Insoluble siliceous matter (sand)..., 5°850 100°591 This manure thus contained no phosphoric acid whatever. In Plot 6 nut-cake was used. This refuse manure contained 4°863 per cent. of nitrogen and 4°12 of phosphate of lime. The dissolved coprolites used in Plot 7 were free from nitrogenized matter. In the commercial night-soil manure was found 4°399 per cent. of phos- phoric acid. The whole produce of each experimental plot was weighed, and the weight of the trimmed roots calculated per acre. The following Table exhibits the yield of the trimmed roots of each plot, calculated per acre, and the increase per acre over unmanured plot :— Per acre. Increase per acre, tons. cwt. lbs. tons. cwt. lbs. Plot 1 (guano) yielded ......... Ariss gusiebessst 11 12 56 6 8 56 Plot 2 (guano and dissolved coprolites) yielded., 12 16 16 7 12 16 Plot 3 (bone-dust) yielded ..........+2.+.. pepe ded Gre O 3.12.0 Plot 4 (bone-superphosphate) yielded ,....... 13 12 16 8 8 16 Plot 5 (economical manure) yielded ....... Jae 4 KOS 0 16 16 Plot 6 (nut-cake) yielded .,...... Fates an ipeslO.. Oia 416 0 Plot 7 ee coprolites) yielded .......,.. 1112 0 6 8 0 Plot 8 (unmanured) yielded ............06-. 5 4 O Plot 9 (commercial night-soil) yielded ........ 94450 4 0 0 Plot 10 (mixture of soot, guano, dissolved copro- lites and bone-superphosphates) yielded., 10 0 8 416 8 It will appear from these experiments— 1. That phosphatic manures greatly increased the yield of the root-crop. 2, That a purely mineral phosphate, when dissolved in acid and quite free from ammonia, gave as large areturn as good Peruvian guano, which is rich in ammonia. 8. That the economical manure, which contained no phosphates, practi- cally speaking, gave no increase in the crop. 4, That manures which are comparatively poor in phosphates produced less effect than manures rich in phosphates. 5. That the form inwhich the phosphates were employed very much affected the result. Thus bone-dust treated with sulphuric acid, and consequently containing 1859, D 34° REPORT—1859. soluble phosphates, yielded an increase of 8 tons. 8 cwt. 16 lbs. over un- manured plot, whereas an equal money value of bone-dust undissolved yielded an increase of only 3 tons 12 cwt. 6. That guano proved to be a less economical manure for Swedes than superphosphate. ; Experiments upon Swedes made in 1856. The preceding experiments sufficiently show the great importance of phosphates presented in a soluble condition to the crop of Swedes. They appear likewise to indicate that nitrogenized or ammoniacal manures are not so essential as phosphates.for. the production of a good crop of roots; but they do not touch the question whether or not ammonia can be entirely dis- pensed with in the cultivation of turnips. This is an important question, for of all fertilizing matters ammonia is the most expensive. My attention therefore was chiefly directed in the next series of experi- ments to study the inflience which purely ammoniacal manures exert on the growth of Swedish turnips. ee’ _ Reviewing the experiments made in 1855, it may appear that the nitroge- nized matters and ammonia contained in the manures employed had some share in the production of the increase ; for it will be remembered that the © addition of a small quantity of guano to dissolved coprolites had a very be- neficjal effect. Again, the fact that bone-superphosphate, containing from ° 2 to 24 per cent. of ammonia, gave a much larger return than the mineral superphosphate, might seem to indicate that ammonia in moderate propor- tion is a desirable fertilizing ingredient of a turnip manure. A critical examination of these facts, however, I think neither proves nor ~ discountenances the conclusion that ammonia has had a beneficial effect on the recorded experiments ; for when comparing the effects of bone-superphos- ° phate with dissolved coprolites, no account was taken of the proportion of soluble phosphate contained in each. I have since ascertained that the dis- solved coprolites contained most of the phosphate in an insoluble state, not near enough acid having been employed for dissolving the coprolite powder. Indeed the coprolite manure contained but little soluble phosphate ; and as insoluble phosphate, in the shape of coprolite powder, has little or no effeet upon vegetation, whilst the insoluble phosphates in bone-dust, partially de- composed by acid, unquestionably are sufficiently available to produce an immediate effect on the turnip crop, the difference in the result may have been due to the larger amount of available phosphates, and not to the am- monia contained in the bone-phosphate. On the other hand, the addition of some guano to dissolved coprolites having produced a beneficial effeet, it - may be inferred that the ammonia in the guano helped to produce this effect ; but since Peruvian guano contains both soluble phosphates and insoluble phosphate of lime in a highly finely-divided state, it may be maintained with equal force that the additional produce resulted from the additional quantity of available phosphates in guano. In short, the experiments in 1855 are not calculated to decide the question whether or not ammonia can be dispensed with as a manuring constituent in a turnip manure. a With a view of throwing some light on the action of ammonia on root- crops, I made in 1856 the following field experiments :— A portion of a field was divided into twelve parts of one-twentieth of an - aere each. The seed was sown on the 21st of June. ; The soil on analysis yielded the subjoined results :— ON THE ESSENTIAL CONSTITUENTS OF MANURES. 3& Moisture when analysed........ aiahwmneest, > tg Organic matter and water of combination 448 od Qts 11°03 eGR OF MOT ea idbis ai clang. cHewledes etewe nae, 298 Alumina . é dildalteae ad aang osrtle ofaidls ae gad 6°06 Carbonate of lime ........0..000e0se es csoriesne «j LZLO Belpbate.of Simp cassia cate vasacn ssa eaadio "78 Alkalies and magnesia (determined by loss).,...... 1°43 Silica (soluble in dilute caustic potash) .......... 17°93 Insoluble siliceous matter (chiefly clay)............ 36°00 100°00 The experimental field was well drained. The surface soil is thin, poor, and full of fragments of limestone, which render the land lighter. Separated from the stones, the soil may be regarded as a stiffish clay-marl, which in wet weather is very tenacious and heavy, and in warm weather dries into hard unmanageable lumps. The depth of the soil was inconsiderable. The twelve experimental plots were treated in regard to manure as fol- lows :— “es the rate © : or per acre. To Plot 1 was applied well-rotten farmyard manure .......... 15 tons. meee 2 was Applied gypsum .. 2... 55 1. ew cee cece ences 6 cwt. To Plot 3 was applied bone-ash dissolved in sulphuric acid .... 6 cwt. To Plot 4 was applied sulphate of ammonia . -s 6cwt. To Plot 5 was applied bone-ash dissolved in sulphuric acid 6 ewt. Bat Sulphate Of AMMONIA, +.i2.--5--.-%- eases 6 ewt.—12 ewt. To Plot 6 was applied bone-ash dissolved in sulphuric acid .... 12 ewt. To Plot 7 was applied sulphate GPMGmSE. -sevtdccnstheatisss 6 ewt. Plot 8 (unmanured). To Plot 9 was applied crystallized sulphate of soda............ 12 cwt. To Plot 10 was applied bone-ash dissolved in acid ......6 cwt. sulphate of potash.............. 6 ewt. sulphate of ammonia............ 6 cwt.—18 cwt. To Plot 11 was applied bone-ash dissolved in acid ............ 3 cwt. Plot 12 (unmanured). The dissolved bone-ash on analysis yielded the following results:— - Water ads £5. cide stenrPeaspas terra sd ips IO Pree TOHEECE os b.cig brag eagles! 6 Guiye on dns j "13 Biphosphate of lime (CaO, PO,) ............ 18°49 ’ Equal to bone-earth rendered soluble rea acid... (28°80) Insoluble phosphates . ...... of ORs Erydrated sulphate of lime .... 02.20. 0550054. 38°39 ORIN AME, He RY cae cs eRe ewe a ee 1°94 pu Ale re hy ok Se AeA te RE ioc ee RGM! LS 100°00 This eromnration ins contained a large per-centage of soluble phosphate as well as gypsum, which necessarily must be formed when bone-ash is dis- solved in acid. It having been stated by a high authority that in Messrs. _Lawes and Gilbert's turnip experiments the sulphate of lime contained in their superphosphate might have had quite as much influence upon the produce as the phosphate of lime, it appeared to me desirable to apply gypsum alone to one plot. Turnips contain a considerable quantity of sulphur ; it is there- fore not unlikely that in soils deficient in sulphate of lime, the artificial sup- ply of sulphates may be found advantageous to the turnip crop. At ee same- 36 REPORT—1859. time it appeared to me desirable to ascertain the effects of alkalies on turnips, and ammonia, potash, and soda applied in the shape of sulphates. We have thus in these experiments sulphuric acid in all the different states of com- bination in which it is likely to occur in arable land. Two plots, it will be noticed, were left unmanured. This should always be done in field experiments ; for otherwise it is impossible to ascertain whether or not an experimental field is uniform, and what are the unavoidable varia- tions in the produce of two plots of the same field. It will be noticed that in nearly all plots nothing but simple salts were used, in order not to complicate the interpretation of the results. It is useful, how- ever, to ascertain how far the natural produce may be increased by a com- pound and approved fertilizer, such as farmyard manure, and in such an ex- periment ordinary manure should be as liberally supplied as in Plot 1. The Swedes were taken up in the last week of November, topped and tailed, and the whole produce of each plot weighed. Table, showing the produce of trimmed Swedes of Experimental Plots, calculated per acre, and increase over the unmanured part of field. tons ewt. lbs, tons ewt. lbs. Plot 1 (15 tons of farmyard manure) yielded.... 7 16 38 ee ae és Decrease. Plot 2 (6 ewt. of gypsum) yielded ........ arse me tages 0 11 30 Plot 3 (6 ewt. of dissolved bone-ash) yielded.... 8 3 38 5 7 40 Decrease. Plot 4 (6 ewt. of sulphate of ammonia) yielded .. 2 12 51 0 3 24 Plot 5 (6 ewt. of sulphate of ammonia, and 6 ewt. of dissolved bone-ash) yielded .......... 8 6 41 5 10 78 Plot 6 (12 ewt. of dissolved bone-ash) yielded .. 8 12 90 &. 17 15 ecrease. Plot 7 (6 cwt. of sulphate of potash) yielded.... 210 O 0 5 75 Plot 8 (unmanured) yielded.................. 3 Ost9 Plot 9 (12 ewt. of crystallized sulphate of soda) ele She AZ c- 2c ae en siete Oe 37 Geo 0 10 46 Plot 10 (6 ewt. of dissolved bone-ash, 6 cwt. of sul- phate of ammonia, 6 cwt. of sulphate of pOkash) yielded. peewee sab g acer + 1G dt ve 4 2 43 Plot 11 (3 ewt. of dissolved bone-ash) yielded .. 7 19 51 5 4 88 Plot 12 (unmanured) yielded ........ eescip a aa 211 19 The natural produce of the experimental field was taken at 2 tons 15 ewt. 75 lbs., being the average of the two unmanured plots No. 8 and 12. These results suggest the following remarks:— 1. The natural produce of this field was very small, as it scarcely amounted to 3 tons per acre; special fertilizing ingredients, such as phos- phoric acid, ammonia, &c., therefore may be expected to have full play in a soil like the one of the experimental field. 2. Only those plots yielded an increase which contained phosphates; the other manuring constituents had no effect upon the turnip crop in these ex- periments. 3. Gypsum cannot replace phosphate of lime in manuring matters. In these experiments it had no effect whatever, which need not surprise if it be oo as that the soil contained naturally } of a per cent. of sulphate of ime. 4. None of the other sulphates produced any effect upon the crop. Sul- phates, especially sulphate of lime, are much more abundant in nature than phosphates, There are few soils which do not contain abundance of sulphate ON THE ESSENTIAL CONSTITUENTS OF MANURES. 87 of lime to supply our cultivated crops with abundance of sulphuric acid. This appears to me the chief reason why sulphates rarely show any effect upon turnips and other crops. 5. The bone-ash dissolved in acid did not contain any nitrogen, notwith- standing 3 ewt. produced as large an increase as 15 tons of well-rotten farm- yard manure. 6. Sulphate of ammonia proved inefficacious when used by itself, or in conjunction with soluble phosphates. It is possible, however, that the quantity of ammonia used in the experi- ments was too large. Similar experiments, which I have since undertaken and hope to continue for a number of years, induce me to believe that on the soils in our neighbourhood ammonia has no beneficial effect whatever upon Swedes. And yet it is quite possible that ammonia may prove beneficial on other soils, which, like sandy soils, do not possess in a high degree the power of absorbing ammonia from the atmosphere, nor to accumulate largely nitrogenized organic matters. But the cases in which ammonia or nitrogen- ized manures are really beneficial to turnips I think are quite exceptional ; and I have little hesitation in saying that a great deal of ammonia, the most expensive fertilizing ingredient of guano, at the present time is wasted in most instances in which guano and other ammoniacal manures are exclusively employed in the cultivation of root-crops. It is certainly a remarkable fact that many thousands of tons of turnips are now raised annually with nothing else but 3 cwt. or 4 cwt. of superphosphate, made exclusively of bone-ash and mineral phosphates. At least 90 per cent. of all the artificial manures that are now offered for sale, whatever their name may be, are in reality superphosphates; and the great majority of superphosphates contains no appreciable amount of nitrogen. Even those artificial manures which, like nitro-phosphate, ammonio-phosphate, blood-manure, &c., convey the idea of manures rich in nitrogen or ammonia, when prepared for turnips, seldom contain any considerable amount of nitro- gen. It is not likely that an intelligent class of men like the makers of arti- ficial manures, would cut short the supply of nitrogenized matters or ammo- niacal salts in turnip-manures, if they had not found out by experience that manures made from bone-ash and sulphuric acid alone, and consequently rich in soluble phosphates, have a more powerful influence upon the yield of root- crops than ammoniacal manures, which are comparatively poor in phosphates. I would likewise specially notice, that even quite dilute solutions of am- moniacal salts retard the germination and early growth of turnips in a remarkable degree. In the preceding experiments I was surprised to find, contrary to all expec- tation, that sulphate of ammonia impaired the development of leaves. Am- moniacal salts are generally considered as leaf-producing, fertilizing consti- tuents; I therefore fully expected to see on Plot 4 a luxuriant development of tops on the expanse of the bulbs. But not only did sulphate of ammonia retard the germination of the seed for a short period, instead of pushing it on rapidly, but throughout the whole season the turnip-tops on Plot 4 looked quite as bad, if not worse, than the unmanured plot. However, in Plot 5, in which sulphate of ammonia was used in conjunction with dissolved bone-ash, I observed, to some extent, the effects which are generally ascribed to ammoniacal manures. ‘The leaves of the turnips in Plot 5 had a much darker appearance than in other plots not dressed with ammoniacal salts, and the plants on this plot, on the whole, looked the most luxuriant. It would appear from this that ammoniacal salts are useless by themselves 38 ; wh Lt REPORT—1859. as leaf-producing substances, when applied to poor soils deficient in phos- phates and other mineral matters necessary for the growth of leaves. : In conjunction with phosphates, sulphate of ammonia in the preceding ex- periment had a marked effect upon the turnip-tops, but none upon the bulbs. Experiments on Turnips made in 1857. _ My experiments in 1857 were principally made with a view of trying whether sulphate of ammonia, applied alone and in conjunction with phos- phates, had the same or a similar effect on richer land than that experimented upon in 1856, and at the same time to determine the influence of nitrogenized matters on the turnip crop. To this end I selected a field which was somewhat deeper, more level, and altogether more fertile than the experimental field in 1856. It yielded on analysis the following results :— Mig istune td! seiaeeotl. abs CR eh eee we ow aah Organic matter and water of combination...... 11°08 Oxides of iron and alumina ..............4. 14:25 Carbonate oflime | {204 7ni Seige rears Pete 10°82 Salphate of lime 055 seer. Be gens! Be eee “71 Mapndiiaice.ws5 sly. ihe (Ree ae StS Ege Se 51 Potash (soluble in acid solution) ............ "32 Soda (soluble in acid solution) .............. 05 Phosplicrie daidesed; 4220 364.40 dade ‘ie 10 Insoluble siliceous matter (chiefly clay)........ 61:78 101°13 On comparing the composition of this soil with that of the experimental field in 1856, it will be found that the chemical characters of both soils are very much alike. The seed sown on the 10th of June was that of white Swedes. The different manures were mixed with three times their weight of fine sifted burnt clay, in order to secure a more uniform distribution of the manure over the land. Each experimental plot measured 5}, of an acre. Leaving unnoticed a number of field trials, I select only those experiments which have a more immediate scientific interest. Plot 1 was manured at the rate per acre with 3 ewt. of superphosphate. Plot 2 was manured at the rate per acre with 3 ewt. of fine bone-dust. Plot 3 was manured at the rate per acre with 3 cwt. of superphosphate, made by dissolving fine bone-dust in 50 per cent. of sulphuric acid. Plot 4. was manured at the rate per acre with 3 ewt. of bone-superphos- phate (purchased). Plot 5 (unmanured). - Plot 6 was manured at the rate per acre with 1} ewt. of sulphate of am- monia. Plot 7 was manured at the rate per acre with 14 cwt. of sulphate of am- monia and 13 cwt. of superphosphate, made by dissolving bone-ash in sulphu- ric acid. Plot 8 was manured at the rate per acre with 14 ewt. of bone-ash dis- solved in sulphuric acid without ammonia. Plot 9 was manured at.the rate per acre with 4 cwt. of gypsum. Plot 10 was manured at the rate per acre with 9 ewt. of burnt clay alone (the same quantity which was used with the manures in the other experiments). Plot 11 was manured at the rate per acre with 3 ewt. of Peruvian guano. ‘On each plot a good plant was obtained, and the crop singled on the 16th of July, with the exception of the plots upon which sulphate of ammonia and guano were used. Although sulphate of ammonia was used in the small pro-. portion of 13 ewt. per acre, and previously mixed with three times its weight ON THE ESSENTIAL CONSTITUENTS OF MANURES. 39 of burnt clay, it retarded the germination of the seed and the growth of the turnips in their first period of existence. Several other experiments, made on a small scale, and all my experiments upon turnips in 1858 and in 1859, confirm the fact first observed by me in 1855, that sulphate of ammonia, instead of rapidly pushing on the young plant, as generally supposed, retards its development in a very marked degree. The produce of each plot was taken up on the 19th of November; after trimming and cleaning, the roots were weighed. The following Table gives the produce in Swedes, topped and tailed, and cleaned per acre, and increase per acre :— Increase per acre. Plot. ah . tons. cwt. qrs, lbs. tons. cwt. qrs: lbs. 1. 3 ewt. of superphosphate .......- 01 FP (OV 166.0 4.5-5 1°20 2. 3 ewt. of bone-dust .....0..0 eee 8-11: .0:.26.turk 19° 9 °°2 3. 3 ewt. of superphosphate, made by dissolving bone-dust in 50 per cent. sulphuric acid .........- Dickhdse Seay Laer) SuwO: 6 4. 3 ewt. of purchased bone-superphos- LR See ae ela eR Oi PRC Beara oBiwg Bl 6 6 Unmanured ..........0seerees Gul 02 84 Decrease. 6. 14 ewt. of sulphate ofammonia .. 5 6 0 21..1 5 2 3 7. 14 ewt. of sulphate of ammonia and Increase. 13 dissolved bone-ash ........ 9 8 0 26..2 11 2 2 8. 14 ewt. dissolved bone-ash ...... 8 18 3 22..2 7 O 26 Peeewt Of avpsum ....ac.ccdence, Gi bBigds V7 in ~— 2 O21 10. 9 ewt. of burnt clay .........+-- 6S 16S Al Hee 6.0! 6 11. 3 ewt. of Peruvian guano...... oa Se OLS Tye) oO eel Plot 1, it will be seen, yielded the largest increase ; from first to last this plot had the lead as to appearance. Thesuperphosphate used in this experimenthad the following composition :— Moistife: sci ccsceesesssotsredeucsie es 10°80 Organic matter®...cccccscseccessccees 4°21 Biphosphate of lime ...0.-+2+--see++-. 20°28 Equal to bone-earth made soluble by acid.. (31°63) 4° Insoluble phosphates .. ..eeee.. sees tice 11 Hydrated sulphate of lime ......eees000. 46°63 Common salt ....... awadWauict's 3 Ui urna rS BANG so os bares Fe ca duee be divede cscs 3°19 — 10000 It will be seen that there is very little nitrogen in this superphosphate, and that in addition to much soluble phosphate it contains about 11 per cent. of common salt. Salt, I am inclined to think, increases the efficacy of phos- phates upon turnips. Plot 2. The bone-dust used upon this plot was as fine as sawdust, and yielded on analysis,— Moisture ....cascccccccsecsocsans 6°86 Organic. matter... 202+ cece esses 13°14 Phosphates of lime and magnesia 68°17 Carbonate of lime .... . - 679 Alkaline salts .......eceeeeeee eens 1:90 BONG. oscil fas Bi aerate. 2 bisiiks “erases 3°42 «gion - 100°00 * Containing nitrogen.......... 34 + Containing nitrogen...... 1:83 Equal to ammonia ...+.. ooee Al Equal to ammonia ..... ai'0222 40 REPORT—1859, Plot 3. A comparison of the produce of Plot 3 with Plot 2 will show the advantage of applying the phosphates to the land in a condition in which they are readily distributed in the soil by the rain that falls, and more easily dissolved in water than the phosphates in bone-dust. These dissolved bones gave on analysis the following results :— Water scion ere. state! yates 6 athe escereee 24°33 Organic matter and ammoniacal salis*.... 5°04 Biphosphate of lime... .....5 606..06056° 17°00 Equal to bone-earth rendered soluble byjacid (26°52) Insoluble phosphates .......-2ccecse00s 969 Hydrated sulphate of lime ........ eossee 39°25 Alkaline salts and magnesia ...........+. 2°81 Sane. 52. Se b Siatvithe coh welels wile Oo cremete pie: / PGB 100:00 Plot 5 (unmanured) gave 6 tons 11 ewt. 2 qrs. 24 lbs. Plot 9 (gypsum) gave 6 tons 13 ewt. 3 qrs. 22 lbs. Plot 10 (burnt clay) gave 6 tons 16 ewt. 3 qrs. 1 lb. The produce of these three plots is so much alike, that the small difference may be safely ascribed to natural variations of the soil. ‘The crop on these plots again shows that gypsum had no effect, and that the experimental field was uniform in its character. Plot 6. The sulphate of ammonia used in this experiment contained in 100 parts,— Sulphate of ammonia ..... Siete te eaeens 98°28 Erxed!salisi. strae «tte cone atercevel viel steve ace ae *78 Moisture ...+.... eee: Fro ciate a ett Fecwers "94 -—— 100°00 We have here actually a decrease of 1 ton 5 cwt. 2 qrs. 3 lbs. of roots per acre. The plants on this plot, I may observe, came up much later, and looked decidedly worse than those on the unmanured plot, or any other part of the experimental field. : It will be remembered that in the preceding season sulphate of ammonia did not increase the yield in bulbs, and likewise prevented the development of luxuriant tops. Plot 7. The addition of sulphate of ammonia to dissolved bone-ash, it will be seen by comparing the yield of this plot with that of Plot 8, gave but a slight increase, amounting to no more than 4 ewt. 1 qr. 6 lbs. per acre. Plot 8. The dissolved bone-ash used in this experiment was the same as that used in experiments in the preceding year, and contained— Biphosphate of lime ..........00+0.005 18°49 Equal to soluble bone-earth ............ (28°80) Insoluble phosphates ............000005 6°43 Moisture ......<. BO ores CUR EEO CRE cic 18°50 Organic matter and ammoniacal saltst.... 52°33 Phosphate of lime and magnesia ........ 21°66 Aikaline alist wate we'd rs 6 Ori din caer GRE Insoluble siliceous matter ..,,..eeee+ee. 1:10 100:00 * Containing nitrogen ........ 1°28 + Containing nitrogen...... 14°16 Equal to ammonia........ os 1°55 Equal to ammonia..+..++- 17°19 ¢ Containing phosphoric acid....s..seese6. 1°46 ON THE ESSENTIAL CONSTITUENTS OF MANURES, 41 The roots on this plot were for a long time decidedly inferior to the super- phosphate turnips. But towards the middle of September the plants took a start, and the guano turnips, so far as the tops were concerned, looked the best in the field. When the crop was taken up, the guano turnips were at least 3 inches higher in the tops, and promised, as far as appearance went, the heaviest crop ; but the actual weight of the plots manured with dissolved bone-ash and superphosphate not containing any nitrogenized matters, showed that there was no advantage in using ammoniacal matters for producing good bulbs on the experimental field. The whole tenor of the field trials in 1857 agrees well with the results of the trials in 1856. The experiments in 1859 afford a fresh proof that salts of ammonia applied alone to root-crops have no beneficial effect, but rather the reverse. They also show that phosphate of lime in a soluble state favours more the production of good bulbs than any other manuring consti- tuent, and that nitrogenized matters are not required in a manure for Swedish turnips, grown on land similar to the experimental field, and under conditions similar to those which prevailed in 1856 and 1857. In concluding this part of my Report, I may state that last year (1858) the results of my field experiments were entirely spoiled by the ravages which the fly and the black caterpillar committed. This year (1859) I have an extensive series of field experimenis upon Swedes. All the experimental plots look remarkably healthy, and I hope in a future year to repeat the result of this year’s trials, which were made like those in 1856, 1857, and 1858, with a special view of determining the influ- ence of nitrogenized substances and ammoniacal salts on root-crops. Before proceeding with another series of field experiments, I may state that I have analysed at various times hundreds of turnips. It would be oc- cupying too much space to give here tabulated abstracts of these analyses. Although I am still occupied with following up this examination of turnips grown under various conditions, and have not as yet arrived at any definite conclusions respecting the influence of different manuring matters on this crop, I may state a few general facts which my analyses have brought to light. 1. In the first place, I would observe that I do not find any striking differ- ences in the composition of roots raised with different manures, provided they are pulled up in an equally mature condition. 2. Soluble phosphates appear to promote an early maturity of the roots, and ammoniacal salts, on the contrary, to retard the maturity of roots. However, on this point my experiments are not sufficiently numerous and conclusive to establish satisfactorily this matter. 3. Roots grown on poor soils and developed more gradually, contain less water and more sugar, and are consequently more nutritious than roots of a large size grown rapidly with much manure. _ 4, Contrary to a very prevalent opinion, I find that the best and most nu- tritious roots invariably contain less nitrogen than inferior less nutritious roots. Indeed I am of opinion that a high per-centage of nitrogen in turnips is a sure sign that the roots have not reached full maturity, and are less wholesome to cattle than well-ripened roots. In the latter I have found, in some instances, fully one-third less of nitrogen than in the same roots at an earlier stage of their growth. The examination of roots, taken once every fortnight from the same field during several successive months, has shown that the per-centage of nitrogen in turnips steadily decreases in the measure in which they proceed towards maturity. In the measure in which the per-centage of nitrogen decreases, 42 ih REPORT—1859. that of sugarincreases. Thus in mangolds, which were as yet scarcely sweet to the taste, I have found as much as 2? per cent. of nitrogen in the dry roots, whilst in the best and fully ripe mangold wurzels only 1-30 per cent. of nitro- gen was found. The nutritive value of different roots, therefore, is not dependent on the relative proportion of nitrogen which they contain, but is regulated chiefly by the relative proportion of sugar which they yield. Field Experiments upon Wheat made in 1859. I have now to record the results of a series of experiments upon the wheat- crop. The field upon which the experiments were made was perfectly level, and apparently of uniform depth and agricultural capability. It was divided into seven plots of ¢ of an acre each. Plot 1 was manured with Peruvian guano at the rate of 24 cwt. per acre; cost £1 19s. 6d. per cwt. Plot 2 was manured with nitrate of soda, 12 ewt. Plot 3 was manured with nitrate of soda, 180 lbs., and common salt, 14 ewt. ; cost £1 12s. 6d. " Plot 4 was manured with wheat-manure specially prepared, and containing both mineral and ammoniacal constituents, at the rate of 4 ewt. per acre. Plot 5 was manured with the same wheat-manure, at the rate of 6 cwt. per acre. Plot 6 (unmanured). Plot 7 was manured with chalk-marl, | ton. The nitrate of soda used in the experiments contained 97 per cent. of pure nitrate, and the wheat-manure on analysis was found to contain in 100 parts,— Composition of Wheat-manure, same as used in Experiments on Royal Agricultural College Farm, March 8, 1859. IVEGISENTE. ais = tate e stab arterials a PORCH Koy. 13-60 Sulphate of amamoania* y eds vues ste) -iels sive pee «++ 1097 Soluble nitrogenized organic mattert ..........-. 8°08 Trisoluble fxs eiopen ivan do abaya Geeta gael cies le LA Biphosphate of Hime. jos s2.0:c0.s¢ ears siusseneis eaigielar eke e+ = BHA Equal to bone-earth rendered soluble by acid ...... (5°52) Insoluble phosphates (bone-earth)...... ae Segae ae 9°45 Sulphate of magnesia’... sj; dee bahia ee iss sealed 61 Hydrated sulphate at lime)...aty lees ses nad ¢es sone 19°73 Chloride of sodium (common salt).......... 00+. 16°84 Insoluble siliceous matters ........... dhe esi neers 2-46 — 100-00 The different fertilizers were applied in the shape of top-dressings on the 22nd of March, and the produce reaped in the first week of August and thrashed out on the 24th of August. i * Containing nitrogen ....-.secseee eeeeeeesecscees 2°32 Biqualto ammonia cares eiale ide iivlcideelde se eeiele va ate 2°82 T Containing nitrogen ...00...csc0.ccnesevesacces 3°53 Aiqual £0 aM MOM Ae cettelciedainalon- nia late) sister ge ins ae 4°28 Per-centage of anhydrous sulphuric acid (SO,) in manure (total amount of sulphuric acid in all the sulphates) 15-93 Per-centage of chlorine ........seeeccecescececces 10°22 Per-centage of. phosphoric acid .:......2.0++ nstedats.s 8:91 ON THE ESSENTIAL CONSTITUENTS OF MANURES. 48 The following Table gives the yield in corn and straw of each experimental plot, the manures employed, and the produce calculated per acre, Each plot measured + of an acre. Manures employed and sown, Produce thrashed out, ; March 22, 1859. August 24, 1859. Plot 1. Peruvian guano, 21 ewt.; cost } Grain, 2406 lbs. or 40;'; bushels ; : £1 12s.6d. (guano, £13 per weight per bushel, 60 to 605 lbs. ton). Straw, 1 ton 3 ewt. Plot 2. Nitrate of soda, 12 ewt.; cost ) Grain, 2280 lbs. or 38 bushels; £1 12s. 6d. (nitrate of soda, weight per bushel, 60 lbs. Straw, £18 10s. per ton). 1 ton 4 ewt. 8 lbs. Plot 3. Nitrate of soda, 180 lbs., and chloride of sodium, 134 ewt.; | Grain, 2436 lbs. or 40,5, bushels ; cost of manure per acre, £1 12s. weight per bushel, 60{$ lbs. 6d. (cost of salt, 30s. per ton; Straw, 1 ton 4 cwt. 48 lbs. of nitrate, £18 10s. per ton). Plot 4. Wheat-manure, 4 cwt. per acre; ) Grain, 2370 lbs. or 394 bushels; cost £1 12s. 6d. (price of weight per bushel, 60 lbs. Straw, wheat-manure, £8 per ton). 1 ton 3 ewt. 92 lbs. Plot 5. Wheat-manure, 6 ewt. per acre; ) Grain, 2652 lbs. or 44: bushels 12 cost £2 8s. (price of wheat- lbs.; weight per bushel, 60 lbs. manure, £8 per ton). Straw, 1 ton 7 ewt. 8 lbs. Grain, 1620 lbs. or 27 bushels; weight per bushel, 60 Ibs. Straw, 17 ewt. 80 lbs. Grain, 1618 lbs. or 27 bushels less Plot 6. Unman ured. 2 \bs.; weight per bushel,604 lbs. Straw, 16 ewt. 80 lbs. Plot 7. Chalk-marl, 1 ton. A comparison of the different quantities of corn and straw reaped on each experimental plot will show,— 1. That the plot manured with chalk-marl furnished as nearly as possible the same amount of corn and straw as the unmanured plot. The produce in the one amounted to 1620 lbs. of corn, and in the other to 1618 lbs.; or each gave within 2 lbs. 27 bushels of corn. In some parts of England chalk-marl is used with considerable benefit for the wheat-crop ; but as the soil on the experimental field is full of limestone rubble, it could not be expected that a marl which owes its fertilizing pro- perties almost entirely to the carbonate of lime and to a little phosphate of lime which it contains, should produce any marked effect upon the wheat- crop. Indeed I did not expect any increase by the application of this marl, and merely used it to ascertain the extent of variation in the produce of two sepa- rate plots. The result plainly shows that the experimental field was very uniform in its character and productiveness. 2. The application of only 14 ewt. of nitrate of soda raised the produce in corn to 38 bushels, and that of straw to 1 ton 4 ewt. 8 lbs. We have thus here an increase of 11 bushels of corn and 63 ewt. of straw. 3. By mixing nitrate of soda with common salt, the produce in corn was raised to 40 bushels, thus showing the advantage of a mixture of nitrate of soda with common salt. 4, Almost the sanie produce as by nitrate of soda and salt was obtained by the application of guano, and by the small quantity of wheat-manure. By the latter 395 bushels of corn, and by guano 40+), bushels were obtained, 44 REPORT—1859. or by the top-dressing with wheat-manure an increase of 124 bushels; and by that of guano an increase of 13 bushels of corn was obtained at an expense of £1 12s. 6d. 5. The larger supply of a mixed mineral and ammoniacal fertilizer gave an increase of 17 bushels of corn and 9 ewt. of straw over the yield of the undressed plot. It will thus appear— 1. That nitrates applied by themselves materially increase the yield of both straw and corn. 2. That the admixture of salt to nitrate of soda is beneficial. 3. That ammonia and nitrogenized matters, which proved ineffective or even injurious in relation to turnips grown on a similar soil on which the wheat was grown, had a most marked and decidedly beneficial effect upon the wheat-crop. In conclusion, I would observe that I purpose to record the effect of the top-dressings used in the preceding experiments upon the succeeding crops. Report on the Aberdeen Industrial Feeding Schools. By ALEXANDER THomson, Esq., of Banchory. Tue study of the possible prevention of crime has of late years received much attention, though not yet so much as it deserves and requires; nor are the principles on which alone crime can be prevented hitherto fully and generally known and admitted. One very important movement in connexion with this subject originated in Aberdeen, and it seems appropriate to lay before the Statistical Section of the British Association, when met in Aberdeen, a brief statement of the origin and results of the Aberdeen Industrial Feeding Schools, and of the principles on which they were established and have been conducted. The origin of these schools was very simple: they arose out of a felt necessity. Crime in all the large towns of Britain had been visibly increasing for many years in a ratio exceeding that of the increase of the population; a distinctly-marked class or race of criminals had arisen, causing much incon- venience to society, and forcing upon thinking men the consideration of what could be done to check so great an evil. Several instructive facts gradually became evident. The stern, harsh system of punishment, long prevalent, was found to have failed alike in pre- venting crime and in reforming criminals, and to have had, on the contrary, the effect of hardening and emboldening in crime those who had been sub- jected to it, and of thereby forming a distinct class of criminals, marked by peculiar features, and highly injurious to the community. It was also observed that certain classes of the population produced more than their numerical proportion of criminals, : Nothing, however, attracted so much attention, from the great annoyance which it caused, as the steady increase of the number of youthful offenders, undeniably guilty of actions which deserved punishment, and who evidently required moral and physical treatment of some sort or other, but who by that which had been applied to them were only made worse until they even- tually took their places, as they advanced in years, in the ranks of confirmed, bold, dangerous criminals. ON THE ABERDEEN INDUSTRIAL FEEDING SCHOOLS. 45 Various persons in different parts of the country suggested and tried temporary expedients to remedy the evil, but the first deliberate, consistent, and permanent scheme, combining feeding, teaching, and industrial training, was organized in Aberdeen by Sheriff Watson, and his plan has been found so efficient, that it is now adopted, more or less exactly, in almost every large town in Great Britain. The immediate cause of this attempt was the pain felt by Mr. Watson, and by many other criminal judges, in the discharge of their ordinary duties. Day after day children of tender years were brought up for trial and convicted of acts undeniably criminal and deserving of punishment, but with regard to which it was very clear that the moral guilt lay not exclusively on the juvenile culprits. They had no doubt done the deed, but who was most to blame for it ? —the actual perpetrator ? or those who had allowed or even led to the com- mission of the offence ? On inquiring into their previous history, it soon became evident, that the root of the evil lay in the want of right parental care and training. The parents were themselves either criminals, or at least wholly careless of their offspring, and left them to grow up as they might, without control, without principle: on the parents clearly lay the primary culpability. Next to them, it lay on the clergymen of all denominations, who, occupied in other and, as they thought, more promising fields of labour, gave a very small share of their time to this particular class; and last, but not least, the blame Jay on the professedly christian public of the country, who, as a body, seem to have agreed to regard these outcasts as a Pariah caste beyond the legitimate sphere of christian enterprise; “no man cared for their souls.” Noble cases indeed occurred, from time to time, of strenuous and successful exertions on their behalf, but they were isolated, unconnected ; and there was no general, no sustained endeavour to reclaim them. What did these children require? It may be all summed up in three words, “Christian parental care.” How was this to be supplied, since the natural parents were unable or unwilling to perform their duties ? There are two opposite dangers to be avoided in applying any remedy: there is the risk on one side of doing too little for the children, so as to fail in training them up aright both bodily and mentally ; and there is the not less serious risk on the other, of doing too much, and thereby giving encourage- ment to listlessness and laziness on the part of the children, and neglect and carelessness on the part of the parents. To avoid these difficulties, it is needful to ascertain exactly what the chil- dren want, and how instruction can be best furnished to them. For their bodies they need food ; for their minds they need instruction in the elementary branches of knowledge; for their success in life they need training in industrial habits, and for their never-dying souls they need abun- dant religious instruction. This is what their fellow-men can do for them. The saving inspiration of the Holy Spirit can be given only by God himself; it is not at the disposal of mortal man, but is given freely in answer to be- lieving prayer. These various requisites were all kept in view at the first establishment of the Aberdeen Industrial Feeding Schools, and they have never been for one moment abandoned. They are the foundation-stones on which the whole structure rests ; remove any one of them, and the superstructure must fall to the ground ; give any one undue preponderance over the rest, and the whole is rendered unsteady and insecure. -In the year 1840 the juvenile criminal population of Aberdeen attracted 46 REPORT—1859. the particular notice of the local authorities, and many inquiries were made as to their numbers and condition. : In June 1841 it was ascertained that there were in that city 280 children under 14 years of age who supported themselves nominally by begging, but actually toa large extent by stealing, and in either case greatly to the annoy- ance of their fellow-citizens. Of these 280 children, 77 had been imprisoned during the previous twelve months. In October 1841 a small sum, under £100, was collected, and with this it was resolved to try what could be done, confident that, if even a moderate amount of success were attained, public support would be freely given. Apartments sufficiently extensive, but otherwise of the humblest descrip- tion, situated in one of the worst districts of the city, were hired, and a teacher engaged. Public notice was given that such an institution existed,. and that poor children who chose would be admitted into it, up to the number. of 60, and would there réceive food, and instruction in elementary religious and secular knowledge, and in such industrial employments as were suited to their years. Attendance up to the time of the passing of Dunlop’s Act in 1854 was wholly voluntary, but the child absent without cause from morning school had no breakfast, from forenoon school had no dinner, and from afternoon school had no supper ; and this very simple and reasonable arrangement at once ensured a more regular attendance of pupils than at most common day schools. The general division of the day was, four hours of lessons, five hours of work, and three substantial meals. The managers did not profess to supply clothing to the children, but, by the kindness of friends, whatever was abso- lutely necessary was from time to time procured. Religious teaching and training occupied a large portion of the teaching hours, and has ever been received with the greatest willingness. The whole arrangements are as simple as possible, and yet they meet ad/ the requirements. of the case. ' : The combination of food, teaching, and industrial training, form together the distinctive peculiarity of these schools, but the food is practically the foundation of the whole system. ‘The children are not at first alive to the advantages of being taught and trained, but they are thoroughly aware of the benefit of being fed ; and this brings them regularly to school. They feel it to be an act of substantial kindness; it at once attaches them to their teacher, and it gradually prepares them to relish and profit by the lessons and work of the school ; it convinces them that the school is meant for their good in the only form in which, at first, they are capable of understanding it. The whole profit of work done goes to defray expenses. This fact is of more value than appears from the amount. It teaches the children from the first that their work is of appreciable value, and also gives them the satisfac- tory feeling that they are not wholly recipients of charity, but that in return for their food and instruction, they are giving all they can, viz. their labour, such as it is. ; It is, however, a great mistake to be too anxious about the earnings of the scholars. That work is most profitable which most tends to habits of patient industry. It matters comparatively little what it may be, provided. it teaches steady perseverance, which is the most valuable of all acquirements, and the one most foreign to the habits of neglected outcasts, Keeping these very simple principles distinctly in view, the first Industrial: School was opened 1st October 1841, with 20 scholars, and the number soon ON THE ABERDEEN INDUSTRIAL FEEDING SCHOOLS. 47 rose to 60, the limit previously determined. During the first six months 109 were enrolled, but, as might have been anticipated on a first experiment, some were admitted who were unsuitable, and others whose parents interfered and removed them, and a few whose wandering habits would not allow them to remain more than a few days—not long enough to ascertain whether they would like the school or not; still, with 60 names on the roll, the average daily attendance for the first 6 months was 36 and for tlie last two 53°50. The amount realized for work during the first six months was £25 19s., 7. e. 20s. a week, or about 14s. 6d. for each pupil. ‘The total cost for each was £4 8s. 10d., or, deducting earnings, £8 13s. 4d., being at the rate of £7 6s. 8d. per annum,—a cost which experience soon enabled the directors greatly to reduce..- From Ist April 1842, to 1st April 1843, the average daily attendance was 52, the total cost of each £6 8s., and the earnings £1 2s. 8d., leaving the expense of teaching and feeding each boy £5 5s. 4d. The earnings per head were less than during the first six experimental months, because there was then a larger proportion of stout working boys than have since been admitted, and who were above the age to which the schools have since been exclusively ' applied. PTrhe close of the year 1843 and commencement of 1844 proved to be the critical period in the history of these schools, and all but fatal to their continuance. ' The public interest at first felt in the new scheme had subsided; the experiment was novel, the results uncertain ; the subscriptions fell off, and but for the liberal aid given by the magistrates of the city, and the Trustees of the Murtle Charitable Fund, the school must have been closed and the experiment abruptly terminated. Even with these aids, the directors were obliged to dismiss all but the most necessitous, and reduce the number on the roll from 59 to 35. The tide was now at its lowest ebb, but it soon began to rise. No one could occasionally visit the school without remarking the change in the outward appearance of the children, and no one could walk the streets of Aberdeen without noticing a perceptible diminution in the number of | troublesome little beggar-urchins. The public came to the conclusion that there was good doing by the experiment, and that, at all events, it should be continued until more certain results were attained, and from that day to this funds have never been wanting ; often low enough to require extreme caution ° in the expenditure, but gradually growing and prospering till the little school on the point of abandonment is now represented in Aberdeen by four schools: a boys’ in the House of Refuge, a boys’ and girls’ at Sugar House Lane, and two separate female schools, having all their valuable and commodious build- ings (except those in the House of Refuge), the unencumbered property of the Institutions, and a regular attendance of from 350 to 400 children. - On looking back to the history of the schools, it is found that the circum-- stances which led the managers to reduce the number of scholars produced ° more than one very instructive result. Let us look for a moment at certain statistics from the year 1841 to the year 1851 inclusive. From the Aberdeen Prison returns it appeared that remarkable variations occurred in the number of juveniles committed. In 1841, when no school existed, the number imprisoned was 61, of whom 26 were natives of the town of Aberdeen, 12 of the county, and 23 were strangers. For the next ten years, with the schools in operation, the numbers for each year were as follows :— 48 REPORT—1859, I Committals | Committals Total Natives of | Natives of Year. |to Aberdeen} to County Town of | County of | Strangers. Prison, Prisons. |CO™mitted.| aberdeen. | Aberdeen. 1842 30 55 30 16 3 ll 1843 63 a5 63 27 25 11 1844 41 43 41 29 4 8 1845 49 oR 49 34 5 10 1846 28 ao 28 18 2 8 1847 23 4 27 8 7 12 1848 15 4 19 9 6 4 1849 15 1 16 12 1 3 1850 14 8 22 ll 8 3 1851 6 2 8 4 3 1 Turning, on the other hand, to the statistics of the Industrial Schools, it appears that in the first year, with one school in operation, the number of juvenile commitments fell from 61 to 30; that in 1843, when the managers were constrained to reduce the number of scholars, the commitments again rose to even more than in 1841, viz., to 63; that in 1844 and 1845, when the school was restored to a certain measure of efficiency, the numbers fell to 41 and 49, while subsequent returns show that each year after 1845, the number of schools and scholars being greatly increased, the number of com- mitments went down and down,—28, 23, 15, 15, 14, 6,—the lowest number which has been attained, and of whom only 4 were natives of Aberdeen. The number has subsequently increased, and seems to stand now at about 35, —about half the number when no such school existed, —but last year, 1858, the number fell to 15. During the first five years after the school was in full operation not one child who had been in attendance there was committed to prison, or fell into the hands of the police for any offence. From 80 to 100 children were in constant attendance ; they were the very children who formerly had furnished the annual supply of youthful offenders, and yet from among them not one recruit went to join the ranks of criminals, and about 70 had been placed in permanent situations, and were from time to time reported to be self-sustain- ing and doing well. These immediate results were more satisfactory than could have been anticipated, or could reasonably be expected to continue ; for no one need expect industrial schools to mould every neglected outcast, who passes a few years under their training and teaching influences, into a steady, consistent christian man or woman for life: they, however, greatly cheered the friends of the instituticns as they gradually became manifest, and they encouraged them to extend their operations. While the schools were progressing there were long and very anxious dis- cussions as to whether or not it was desirable to dodge the children in con- nexion with the schools, and only a small majority decided in the negative, As this is a vital question in the management of industrial schools, it may be well to state briefly the facts and arguments on both sides. 5 In favour of providing lodgings in the school-buildings there were two principal arguments, both very obvious: Ist, that by thus retaining entire possession of the children their moral training would be carried on before and after school-hours ; and 2nd, what was regarded as still more important, that thus they would be preserved from the contaminating influence of their homes, where it was to be feared that the moral lessons learned during the day would be neutralized by evil precept and worse example. ON THE ABERDEEN INDUSTRIAL FEEDING SCHOOLS, 49 There is so much apparent force in these considerations, that it is only when the subject is viewed in all its relations, and especially when the light of God’s word is brought to bear upon it, that a rightful decision of the question can be attained. The family is the place ordained and prepared by God for the training and up-bringing of children, and this is an ordinance which man can never infringe with impunity. To collect numbers of children and manage them in masses is sure to de- stroy individuality of character, while providing everything for them effectu- ally destroys energy of character, and prevents the acquirement of habits of industry. Under such treatment abundance of knowledge may be commu- nicated, but no training for the active struggle of life can be given. The whole system is artificial and foreign to the state of that society in which the children are soon to take their places. The experiment has been fully tried in Scotland by the hospitals so pro- fusely endowed, and long erroneously considered as objects of self-gratula- tion by every Scotchman, and in England by the poorhouse schools; and in both cases has signally failed. The inmates take their places in the world with their heads stored, it may be, with valuable knowledge, and even quite capable of passing a strict examination in many branches, but with all their energies deadened through want of use, and wholly incapable of applying their knowledge to any useful purpose, unable to rely upon their own exer- tions because they have been trained up in dependence upon others for all they need. The first practical lesson to be impressed on the mind of every child, and especially on those who have to support themselves in life by their labour, is that they must, under God, depend on their own exertions for success. In an hospital, or a poorhouse, no such lesson is or can be taught; on the con- trary, they are taught practically that they may safely depend for everything on others. This is not the wish nor the intention of the hospital or poor- house managers, but the necessary result of their systems. The other aspect of the question, arising from the contamination to be dreaded from a wicked parent’s home, is still more serious. At first sight it looks absurd to train a child carefully for the greater part of the day, and then deliberately, knowingly, to expose him during the re- maining hours to see and hear all that is offensive and abominable in tte con- duct and language of a drunken mother or an abandoned father, or vicious, dissolute neighbours. If the object to be attained were to train up a child in absolute ignorance of moral evil, then a well-regulated hospital would be exactly what is re- quired ; but no man will venture to maintain that this is the sort of training required to adapt a child for a useful life. Our business is not to train up in ignorance of the existence of evil, but to teach children what sin really is in itself, and in its consequences ; how hateful it is to God, how ruinous to man. This is the Bible mode of teach- ing children as well as men and women, and from that certain rule we never can depart with impunity. It is most painful to think of the moral evils to be witnessed in many of the dwellings of our crowded cities, and every exertion should be made to cause them to cease; for while they exist they go far to neutralize every effort for the good of the poorest classes, and go on producing a steady supply of neglected juveniles; but that is not the present question; it is, What is the pee wey of bringing up the children belonging to that class of society and 1859. E 50 REPORT—1859. exposed to all these evil influences? Is it by shutting them up for a certain number of years from the knowledge of such things, and then sending them out at once into the midst of them? or is it by teaching them, so far as man can do it, to know and hate sin, and to flee from it? It is a dangerous step to break up a family, and to tear asunder the ties which bind parents and children together. Few, indeed, are the parents in whose hearts love for their children is wholly extinguished: it survives the _destruction of almost every other right feeling in the heart, and it is through this that other good feelings may possibly be rekindled and brought into beneficial operation. It is marvellous to witness the good which flows from the influence of one right feeling beginning to work in a heart which seemed to be seared and dead to every good impression, Few are the parents who will deliberately teach their children vice and crime; on the contrary, the majority carefully conceal their own wickedness from them, There are few human beings in whom conscience is wholly dead, who do not feel something of the burden of guilt on their own heads, and who would not, if they could, deliver their offspring from it. The principal exception to this is when reason, and every other faculty, is overpowered by strong drink; but even in this case there is the sad, the melancholy advan- tage, that the children get many a practical lesson of its fearful consequences, and while we deplore the fact, we need not therefore shut our eyes fo this part of its results. While this matter was under consideration the further question occurred, What effect will be produced on the wicked parents by the return of the children from the school to their homes? Will it do any good to the parents? More than one case soon became known where unmistakeable benefit arose to the family from the school-children, The parents were in- terested in hearing what was done at this new school; they saw that at all events their children were well fed for the day, made tolerably clean, and kept out of harm’s way. Verses of hymns or texts of Scripture were re- peated and listened to; in short, it appeared that the daily return of the child from the Industrial School introduced the first feeble glimmering of improve- ment at home; it might be only a little sweeping of the floor, or a little arranging of the miscellaneous articles in the room, as they were accustomed to do or to see done at school, but still it was a step in the right direction, an introduction of ameliorating influences. Subsequent experience has shown that some of the children have acted, and are now acting, as little Home Missionaries, conveying the saving truths of the Gospel to parents and brothers and sisters.’ It was also discovered that some of the children occasionally denied them- selves a portion of their bread and carried it home to supply, so far, the wants of a starving little brother or sister; and here was another humanizing influ- ence brought to bear on the family. Altogether, the question was under consideration for years, and the ulti- mate decision was, not to attempt to lodge the children as part of the system, but, in exceptional cases such as orphans, to proyide that children should he boarded in a family, and even then only one or two children in one family, unless they were brothers and sisters. _ Few such cases have occurred, and they are provided for without encroach- ing on the general funds. The decision was no doubt greatly promoted by the managers seeing that they could carry on their work if they did not attempt to lodge, but that, if they did, their funds were wholly inadequate to the expense, ON THE ABERDEEN INDUSTRIAL FEEDING SCHOOLS. 51 It was fortunate on every account that it was so, and the results have been most satisfactory. While thus fixing the exact extent of their field of labour,—and the general principles on which the work was to be conducted,—the managers were gradually pushing forward their attempts to get under their care all the neglected outcasts in Aberdeen. The first and most natural step was to commence a school for girls similar to that for boys. It was opened on 5th June 1843, with only three girls, and the number was gradually increased to 20, 40, 50, and at last to 60, the full number for which accommodation was provided. The results were, if possible, more satisfactory than with the boys. A poor half-staryed outcast girl is felt by all to be a more painful sight than a boy in the same condition. She seems to have been forced farther below her right place in society than the boy, and to be less capable of struggling for herself, Experience, however, soon proved that ameliorating influences acted more rapidly, and perhaps more permanently, on the girls‘than on the boys. The change produced by a few weeks of careful feeding and training upon the most abject was so great, that the ladies who devoted themselves to the pecsons enterprise had every encouragement in their work and labour of ove. In December 1844, the first complete year’s report of the girls’ school stated the number on the roll at 49; and next year, 1845, it was above 60. During the third year 35 girls left; 16 because their parents had become able to provide for them; 5 got employment in manufactories; and 7 as domestic seryants; 7 deserted, and 1 died. During the fourth year the attendance varied from 56 to 69; 23 left for domestic service, and 31 were removed by parents, as in the previous year ; and this must always be regarded as one of the most satisfactory results of the schools, arising either {rom improved pecuniary circumstances, or from improved moral feeling on the part of the parents. The expense of each pupil was £3 18s. 103d., and the earnings of each 6s. 114d., leaving the net cost to the institution £3 11s. 113d, The amount of earnings was small, but as much as could be expected, considering that nearly half the children were under 9 years of age, most of the rest from 9 to 11, and only 10 of them above eleven, The cost for feeding and teach- ing the girls was nearly twenty shillings a year less per head than for the boys. In 1847 circumstances led to a division of the girls’ school into two, and both have ever since gone on doing their work effectually, having convenient buildings, situated about a mile apart from each other,—one purchased, the other built for the purpose, and both of them thoroughly adapted to the system of the schools. Soon after the original schools had begun to prove their usefulness, it became clear to the managers that they were not accomplishing all that ought to be done, that there was still a portion of the neglected outcasts whom they were not reaching, and this forming the very class for whom the schools were originally intended—the little beggars and pilferers who infested the streets, and whom it had hitherto been impossible to draw to the schools. It was resolved to make a bold and resolute assault upon this class, and to compel them to be ameliorated whether they or their parents wished it or not. The Local Police Act for Aberdeen happily contained a clause giving EZ 52 “REPORT—1859. power to put down begging. It provided for the punishment of beggars, but it did not devise any mode of caring for the beggar, whether old or young, or putting him in the way of supporting himself. It was passed before the enactment of the present Scottish Poor Law; it did one half of the work, it left the other half either not done or to be accomplished by voluntary enterprise. This clause was employed in a way not perhaps intended by the Legisla- ture, but still within the scope of the law, and which has proved most salu- tary to the community. The intended proceeding was carefully explained to the authorities, and their support and assistance were judiciously given. The managers of the Soup Kitchen gave the free use of their buildings, and this most important social and moral experiment was commenced with a sum of four pounds sterling, raised by subscription, not doubting that if good resulted the necessary funds would be furnished,—and so they have been. ; On 19th May 1845, instructions were given to the City Police to lay hands on all the children found begging in the streets, and bring them to the Soup Kitchen, and in the course of the day 75 were collected, of whom only 4 could read. The scene was one never to be forgotten by the few who witnessed it. Naturally alarmed at their capture, wholly ignorant of what fate might be awaiting them, they cursed and swore, kicked and fought and bit, but by firmness and kindness they were greatly subdued before night. The most obnoxious part of the proceedings was the compulsory washing of hands and faces little accustomed to soap and water, and the only accept- able part was the ample supply of good food. Teaching could scarcely be said to commence on the first day, which was devoted to training. Gradually during the day a certain amount of order was established : the boys began by degrees to understand what sort of place they had got into, that the treatment was not altogether to be condemned, that though the cold water might be a very unpleasant application, and the proposed lessons a very wearisome infliction, still the soup was very good and the bread very abun- dant; they had never had so much good food before, and it was worth endu- ring some discomfort to obtain. Some such reasoning seems to have passed through most of their minds in the course of the proceedings. At eight o’clock they were dismissed ; they were all invited to return next day, when they should have the same discipline and the same feeding, toge- ther with more regular teaching, and at the same time they were distinctly informed that they might come or not as they pleased, but that begging in any shape would not be tolerated; that their wants would be supplied as they had experienced in the school; that their choice now lay betwixt starving, or the prison, or the school, and they must make it for themselves. Next day the greater part of the boys returned, and the managers felt that they had gained a great victory, and that a new and vast field of usefulness now lay before them. They entered vigorously upon it, and the school has been in active and useful operation down to the present day. This school at once produced visible effects ; the immediate removal of the whole of the troublesome boys who infested the streets made an unmistake- able change much to the advantage of all classes, and when it was necessary to raise funds for its support the working classes gave most gratifying testi- mony to their sense of its value. ‘ The wealthier classes of the community subscribed £150, but the working ON THE ABERDEEN INDUSTRIAL FEEDING SCHOOLS, 53 classes, men and women depending on daily toil for daily bread, contributed no less than £250!—and when some of them were asked why they contri- buted thus liberally to support a school at which their own children would not be scholars, the reply was, “Before this school was opened we were afraid to trust our children a moment out of doors alone and unguarded, for they were exposed to learn, and did learn, all manner of mischief; but now the school has cleared the streets of the little vagabonds who corrupted them, and we are not afraid to let our own children out, and therefore we subscribe to the school.” This honest practical testimony to one good result, and that not the imme- diate object but the indirect effect, of the school, is invaluable, and at the time was felt to be most encouraging. During the first year the total number of names placed on the roll was 159, of whom 18 were soon dismissed as unsuitable, 34 deserted, or were removed. by their parents, 26 got into employment, 7 into other institutions, and at its close 74 remained on the roll, of whom 43 were boys and 31 were girls. Of these, 25 were from 3 to 7 years of age, 36, from 7to10 3 11 ,, from 10 to 13 * 2 above........ 13 oc Thirty-four of those in attendance at the end of the year had been admitted during the first month, and of these, 2 could read, and § knew the letters at admission ; and by the end of the year 23 could read tolerably, and 24 could read a little. _ Their religious instruction had been utterly neglected; few of them had ever entered a church. Before the close of the year they were all in the practice of attending church accompanied by the teachers, and received care- ful religious instruction every day, but especially and very fully on Sunday evenings. The attendance became very regular, and, what was especially satisfactory, very few of the children were convicted of any offence. The good food procured the attendance, and the twelve hours spent in school left little opportunity to commit crime; thus commencing the abandon- ment of bad, and the formation of good habits, before any principle could be instilled. The value of the work done was very small, but the police authorities most judiciously paid the salaries of the teachers, and the managers of the Soup Kitchen gave the use of their buildings without rent; so that the only outlay from the funds of the institution was for food, and for a partial supply of clothing, which was absolutely necessary. The average cost per head for the first year was £4. This has proved the most valuable of all the schools; it at once attacked the evil at its fountain-head, and the fruits speedily appeared in the almost total cessation of street begging, and the gradual diminution of juvenile vagrants and offenders. After a time the police authorities and the Soup Kitchen managers with- drew their support, and they acted wisely in so doing; the school has ever since been supported by voluntary contributions; its proper name is “ The Juvenile School of Industry,” but in Aberdeen it is best known, from its locality, as the Sugar House Lane School. The number in attendance varies from 50 to 70 boys and as many girls. 54 REPORT—1859. The school-rooms are on different floors and most commodious; the only want is a play-ground, which from the situtation is unattainable. Considerable difficulty was all along felt in confining the operations of the schools strictly to those children who required their aid, and excluding those whose parents or friends were able to maintain them at ordinary schools; and this was a most important matter, both in order to spare the funds of the schools and to satisfy the public mind. To meet this difficulty the “Child’s Asylum Committee” was invented and has been most successful. The duty is carefully to investigate every case in all its cireumstances, and admit or reject, or hand over to some other in- stitution, as may be found proper; in short, to interpose an effectual check betwixt the little mendicants and the school, in order to prevent what was not unlikely to happen,—a resort to street begging in order thereby to get at the good food of the school. At first it met daily at 10 a.m.; but this soon became unnecessary, because there were not daily cases to examine, but it is still summoned whenever its services are required. It was instituted in December 1846, and is a numerous committee, being composed of gentlemen who are either Magistrates of the City or Commis- sioners of Police, or Members of the Poor Law Boards of St. Nicholas and Old Machar, Directors of the House of Refuge, or Members of the Joint Committees of Management of the Boys’ School and the Juvenile School; in short, of members of all the public bodies interested in the matter. The inquiry is most searching into every circumstance which can guide in coming to a decision suited to the case, and its working has been most satisfactory ; very few, almost none, have been admitted to the schools since 1846 who were improper objects ; and it has not unfrequently happened that remonstrances and counsels given to parents had the happy effect of bring- ing them first to feel and then to undertake and discharge the duties they owed to their hitherto neglected offspring. During the first five years this Committee investigated the cases of 700 destitute children, most of whom were admitted into one or other of the schools, and 198 of these were brought up to the Committee by the police. The Ladies’ Committee of the female schools make precisely similar inquiries into all the cases brought to their notice before admission. The progress of the schools has been steady, and their good effects have become more and more visible every succeeding year, and have been demon- oa only more clearly by facts which at first seemed to militate against them. oe remarkable proof is derived from returns furnished by the rural police. It was a well-known fact that children of very tender years were sent out by worthless parents to wander alone through the county to support thems selves by begging and petty thefts, and that still greater numbers accompa- nied their parents to add force to their claims for charity, while a few were lent or hired for the same purpose to parties who had no suitable children of their own. The constables of the rural police were instructed to return as correctly as possible the number of these children whom they encountered in their daily rounds. From the nature of the case the returns cannot be absolutely correct ; but still they approximate to the truth, and the variations from year to year give information of much value. ' ON THE ABERDEEN INDUSTRIAL FEEDING SCHOOLS, 55 The following is the Return for Ten Years. Juveniles in company} Juveniles Year. with Adults, alone. 41-42 272 57 42-43 370 77 43-44 302 60 44-45 302 65 45-46 250 14 46-47 211 6 47-48 225 6 48-49 239 1 49-50 260 2 50-51 170 4 J ns Compare these returns with those already given from the prisons and from the industrial schools, and the result is as clear as figures can make it, that precisely as the schools are in vigorous operation or not, so the number of youthful vagrants diminishes or increases. We have now had seven more years’ experience, and the results are equally instructive though produced to some extent by circumstances which at the time were most unsatisfactory. To bring these out we must again have recourse to the Prison and Police returns. Commitments to Prison. Committals |Committals Total Native of | Native of Total Year. to neo be Sasonaied Committals.| Town. County. 1852 23 1 24 1853 24 1 25 1854 47 2 49 1855 34 3 37 1856 34 9 43 1857 31 9 40 1858 12 3 15 NN Juveniles apprehended. Year Juveniles in company} Juveniles ; with Adults. alone. 1852 258 8 1853 585 21 1854 456 17 1855 416 8 1856 297 9 1857 199 lhe 1858 169 4t It will be observed that a very sudden and remarkable increase took place in 1853, 1854, and 1855, both of commitments of criminals and of juvenile vagrants met by the police. The school managers were completely perplexed and somewhat dismayed. Were the principles on which they had acted unsound? or had they failed to apply them aright ? Was the great enterprise, hitherto so successful and a cause of so much thankfulness, after all to prove a delusion? They could not believe it, and yet the increase of offenders was ' * City of Aberdeen. + Not one of these 4 belonged to the City or County of Aberdeen. 56 REPORT—1859. an undeniable fact. Many anxious meetings were held, and many searching inquiries were made, but for a long time they could only point to the ordi- nary producing causes of juvenile crime,—drunkenness of parents, parental neglect, cheap theatres and dancing saloons, and the facilities afforded by brokers’ shops for the sale of small stolen articles; at last the active cause was discovered. Rival institutions had been set up; schools attended by large numbers were in active operation, not to teach honesty and virtue, but to teach theft and crime; and at the same time to provide every facility for the disposal of stolen property, and to prevent the detection of the offenders. Various wicked inducements were also held out to the unfortunate juve- niles, tempting them in a manner utterly opposed to all good order and even decency, but which were not wanting in their results; they had their attrac- tions, and they did their work. From 1852 or 1853 to 1855 there were two if not more of these “schools for crime” attended by parties of from 12 or 14 up to 30 or 40. This appalling discovery explained the whole mystery. Ultimately several of the teachers of crime were brought to trial, convicted, and their establish- ments broken up, and then the number of offenders speedily diminished, though, of course, time was required for the complete wearing out of the effects of such a nefarious system. It is worthy of notice that these teachers of crime were tried and con- victed of theft, or of recetving stolen property—not one of them for the infinitely more atrocious crime of teaching little children to be criminals. There seems to be at present no law which can touch them for so doing, and yet there is scarcely a greater crime which man or woman can commit. With this exception, which only proves in the strongest manner the value of Industrial Feeding Schools, the whole institutions have gone on and pros- pered, quietly doing their work, with those trifling alternations which occur in all children’s schools, and which are of the greatest use in keeping the energies of managers and teachers in constant activity. It would be useless to read, for no one could follow, statistical details exhibiting all the particulars of each school for each year, with the ages, parentage, and disposal of each child, but they are now produced for the in- formation of those who choose to examine them; and they will be found full of interesting and instructive facts, all tending in one direction—to demon- strate that well-managed schools on the Aberdeen principles have, without doubt, solved the important question how the annual supply of juvenile criminals may be cut off at the fountain-head, and how multitudes hitherto allowed, if not constrained by the force of surrounding influences, to grow up into criminals, a torment to themselves and to society, may, by God’s blessing, be transformed into self-supporting respectable members of society. The first ten years of the schools saw them, after all their trials and vicis- situdes, firmly established in Aberdeen, and not confined to it, but already extended to most parts of the country. The history of their introduction and progress elsewhere lies beyond the purpose of this paper. The subject gradually took more and more hold of the public mind. The managers in Aberdeen early saw the importance of their schools receiving public sanction, and brought forward the subject in reports, memorials, and petitions, until at length it was taken up by the Legislature ; and the stamp of the nation’s approval of the system of Industrial Feeding Schools was inde- libly fixed upon them by the passing of ‘‘ Dunlop’s” Act, on the 7th of August, 1854, applicable to Scotland only; and on the 10th of the same month, of “ Palmerston’s” Act, applicable to the whole of Great Britain. ON THE ABERDEEN INDUSTRIAL FEEDING SCHOOLS. 57 These two statutes have introduced an entirely new principle, and in fact revolutionized the long recognized principles of our criminal law. They adapt and give legal sanction to the axiom that “ Prevention is better than cure.” By Dunlop’s Scotch Act, vagrant and neglected juveniles apparently under fourteen years, wandering about with no visible means of subsistence, may be sent by magistrates to a Reformatory or Industrial School, duly sanctioned by the Secretary of State, there to be trained and educated, but not to be detained, without their own consent, beyond the age of fifteen. By Palmerston’s British Act, magistrates are in like manner authorized to send juvenile offenders under sixteen to Reformatory Schools duly sanc- tioned by the Secretary of State, for not less than two, nor more than five years, but only after undergoing an imprisonment of not less than fourteen days. Both statutes make provision for recovery of the cost of such young per- sons from the parties legally liable; both authorize grants of public money in aid of the schools, and both are entirely voluntary, or permissive, not obligatory. Magistrates may avail themselves of them or not as they think proper ; and as the matter was new, and wholly untried as a legal proceeding, it was prudent thus to proceed. The time, if not yet arrived, must soon come, when no outcast children shall be sent to prison, but all sent to Reformatory Schools, there to be fed and taught and trained, without having the prison brand stamped upon them which is required by Lord Palmerston’s Act,—a temporary concession to old and deep-rooted prejadices. Under Dunlop’s Act, if parties interested find security to the amount of £5 for the good conduct in future of any young person sent to school under the Act, then such young person is removed from the school and handed over to their care. This clause is liable to considerable abuse, and ought ere long to be repealed: parties professing so much interest in these young persons ought to show it at an earlier period, and take proper care of them before they become either vagrants or criminals ; and the nation ought not to allow those who have proved themselves so indifferent in the matter to interfere, and deprive the children of all the advantages of an Industrial School, without really offering anything certain and of equal value in return. Those two statutes have already been productive of much good, and both magistrates and the public are daily becoming more willing to avail them- selves of their provisions. - In order to have the benefit of the Palmerston Act for older convicted juveniles, a Reformatory has been erected near Aberdeen, mostly from the judicious application by the trustees of the late Dr. Watt, of part of the charitable funds left by him at their disposal. The building is plain, but most suitable for about fifty boys, with plans ready for its extension when required, standing ona farm of fifty acres, the property of the institution, and at present having between thirty and forty inmates. It has been only about two years in operation ; and though all promises well, it is not yet time to look for results ; only one or two, and these under peculiar circumstances, have as yet left the institution; the period of sentence of the first admitted has not yet expired. One satisfactory statement may with confidence be made, and that is that most of the inmates are thoroughly happy and contented in their abode, and this is one great step to their reformation. Those who have from the first taken an active interest in the cause of neglected juveniles, can hardly realize to themselves the progress which has been made in less than twenty years. In 1840 no special provision existed for their behoof ; they bad full per- 58 REPORT—1859. mission to do what they pleased, and when they became troublesome to others, the prison, and perhaps the lash, were the only remedies applied. In 1841 the first Aberdeen School of Industry was opened; the experiment went on and prospered ; the example was followed ; other towns opened simi- lar schools; the system was found to do much good wherever it was tried. The public became more and more interested, for the good done was very perceptible, and the money-cost was very small; and as each town easily furnished a few zealous ladies and gentlemen to superintend the work, they were thankfully permitted to do so. Then it became very evident that to punish criminals as of old was very costly, and rarely led to their reformation; but that to prevent crime was comparatively easy, and also far less costly. These opinions gradually established themselves in the public mind, and from it of course took possession of the Legislature; and in about fourteen years from the opening of the first Industrial School, the Imperial Legislature passed the two leading statutes which firmly established them as fixed por- tions of our social system, and finally adopted the principle of endeavouring to prevent rather than to punish and reform. Hitherto, of course, only partial and local results are seen; soon, greater and more extensive are to be expected. What, then, are the principles on which these schools depend for success ? They are so very simple that there is no small risk of their being overlooked in carrying out the actual working. The schools supply what the children need, and what they cannot get for themselves—food, teaching, training; but they leave their energies free, they only seek to turn them from evil to good. Energy, activity, diligence need to be fostered in the young quite as much as their mental faculties, and any system of dealing with them which deadens these is fatal to future success. The want of men of eminence from among the tens of thousands who have been educated in poor-houses and hospitals, combined with the pre-eminence of men who have struggled in early life against every ditticulty, prove the truth of this. It is no kindness to any one to deprive him of self-reliance, though it is often less troublesome than to enable him to depend on himself. The Legislature has done well in the encouragement it has given to these. schools, but it will be a fatal step if they try to do too much, and place them entirely on public support. It is absolutely necessary that a large amount of voluntary unpaid energy enter into the working out of the system. There seems to be a social principle, not yet very much appreciated or understood, which makes it necessary that the best laws shall always be supplemented by private voluntary enterprise. Let the law provide as it may for the poor, for the sick, for the criminal, there will always be found work just at the boundaries reached by the law which must be undertaken by the free-will enterprise of individual activity ; otherwise there will be great blots and scars on the face of our social system, great evils without remedies ; and this is in truth a vast blessing conferred by God on man, for it provides work equally advantageous to the rich and to the poor. The principle which ought to govern all connected with the work of Indus- trial Schools is very extensive, but itis very simple,—earnest, hearty love of the outcast members of the human family viewed as immortal beings. As the love of God to man is the source of all human happiness, so the . love of men to one another is the great remedy for the social evils which afflict this earth. - The highest display of God’s love to man is manifested in the great scheme ON THE ABERDEEN INDUSTRIAL FEEDING SCHOOLS. 59 of salvation through our Redeemer ; and the best proof man can give of his love to his fellow-man, is to do whatever man can do to bring him to know and to receive the glad tidings as revealed in the Scriptures of Truth. This is the plan which God himself has appointed ; and every endeavour to reform men, not based on God’s Word, and not guided by its precepts at every step, must fail of success. It is a good thing, no doubt, for society that neglected outcasts should be reclaimed and trained up to be self-sustaining useful members of the com- munity ; but if the managers of Industrial Schools look no higher than to mere temporal results, they must in most cases fail to attain even what they desires The only well-grounded hope of success is to be found when the training to pass usefully and creditably through this world is based on, and made sub- servient to, the higher and holier training which communicates that knowledge which alone leads to life eternal. Statistics illustrative of Progress of Aberdeen Industrial Schools. Table of the Ages of the 69 Boys at Industrial School, 30th March, 1844. Under To) eddie hoa sims see oA Between 7and 8 ...:.+...66.5 5——9 % Sand Q)iseetaacceca! MM 3 Sand 10°. .%stees cise £8 Be 10 Bnd 1D". 32 ks 22s 3 11 g LB and 12 wsccecsccess 5 ——46 % . &2 and 13). cea ks 2212 -t) 10 %§ USand 14. seed. os si 5 ——15 Thus of the 69, 9 were under eight years of age, and 45 were from eight to twelve years old, and 15 from twelve to fourteen ; 36 had lost their fathers ;. 4 only had lost their mothers. Ist April 1845, 72 Inmates. Under Time gente s eohix es as &6 Between 7and 8.....:..2:3.. 11 ——17 as Sand OQ s.sssesig3r 7 4 9 and 1G) sessse3 8 885" 15 3 fOrand TP. 3 ees 62s: 11 a° “and 196; See hese sea? 4, —=—37 Se Utand Ud 50.285 Sees 8 TStand! 14.3335 50s 3 —=+—Il11 > Thus of the 72, 17 were under eight years, and 37 were from eight to twelve years old, and 11 from twelve to fourteen. The fathers of 38 were dead, and eight more had deserted their families, making 46 in fact fatherless ; two only were motherless. Table of Ages of 91 Boys on Roll of Boys’ School, Ist April, 1859. Bingee "(Feats ns oe 09,5 2009s 8 Between 7and 8.........:+. 8=+—I6 “¢ OVA tO chars 5 Se Fese! 20 9 Giatd.1O cavaseaacs ve 92 PLO PAUGOI oes esos s cc LS De Landes ee scre a res 6 —6l Fe AND TD ro ses Ps 0ST 6 sy er ONE eve ss knee a3 6 5 PS ANTS seer es et . @2—d]4 60 REPORT—1859. Thus of the 91, 16 were under eight years of age, and 61 were from eight to twelve. 34 have mothers; only 9 have fathers; only 48 have both parents alive ; 8 have been deserted by fathers; 1+ are illegitimate. The comparison of these Tables for 1844, 1845, and 1859 shows that the schools are now attended by the same description of children as when they were first opened. Table showing progress of Boys’ School of Industry. Average | Average ox bs plan = ment direc! Year. | attendance.| Total cost. Food. Earnings. | Net Cost. | fom School, eG Se the = a Bae lie See ye B 2 I GNNT# 1841-42 36 8 6 8 411 0 014 6 (ie Pa - toe 1842-43 52 6 8 0 410 4 Liy2e8 Bir esr e 1843-44 45 512 0 4 1 0 140 4 8 0 aes 1844-45 52 6 0 0 4 0 0 110 0 410 0 17 1845-46 49 6 0 0 3 8 6 ] 10" 1 4 911 22 1846-47 66 5 17 10 314 0 (116 4 41 6 14 1847-48 66 518 9 4-1)°9. |} 144-9 4 4 0 28 1848-49 64 510 7 ale % 17 6 43 1 18 1849-50 61 Ley eae’ 310 6 117 4 3 910 14 1850-51 64 418 5 a We} 114 4 ey: ams 7 1851-52 72 4 510 3.0 0 ,1 510 3.00 12 1852-53 66 311 5} 3 0 6 10 6 210 114 8 1853-54 61 4 3 8} oy OMG oq a. Fal 3.2 44 ll 1854-55 53 4 7 9 3°00 11 0 9 3.7 OF 14 1855-56 65 317 8% 34: 8 015 3 3.1 #4 17 1856-57 53 3 10 11% 3.01 1 0 83/210 34 15 1857-58 52 LTR 219102 ,|018 7 314 6 vf 1858-59 77 4 7 93 aro eZ | 016 03 |3 11 93 18 Table of Ages of Children at Juvenile School, Sugar House Lane, April 1846.—Number on Roll 73. 3 years Of age...2.e..-222 3 4 ” Se aoe 5 AQ 5 ” cere eeeseses g 6 os cla ohare, okt Ss --.. lO——25 under 7 7 ” Cys eielninitetctiatataatian ee 8 ” ee 7 9 ” eeereee were 10 >» Saini eae ce ramen 386 from 7 to 10 11 » ait. at atch ea ae 12 gi ines iS cae aati oat 13 ” eseesucessve) (ll from 10 to 13 2 were orphans; 5 had fathers only; 47 had mothers only ; 20 had both parents alive ; 2 only could read on admission; and 8 knew the letters of the alphabet. Average expense about £4 a year; earnings very small. Table of Ages of 132 Children in Juvenile School, on 1st April, 1859. Under. pS years ys. 0.6 oni ss 8 Between 5and 6G............ 12 3 Giang yen cuslecdeteties: 320) 2 7 and Oi taiie intern gee ighaie 27——67 ON THE ABERDEEN INDUSTRIAL FEEDING SCHOOLS. 61 Between Sand 9 ....ecceeers 16 ” G9 and-IO'..:. 6). 26 PPorOrandiyyres ee ee Ji gy EBRATIONZE a ss eres oreo cere 11——60 Bay SUNIL gets a laive cies’ sca azo 4 PAD hae (osc 0 Le Cena a i ea 2 eS Thus of the 132, 67 are under eight years ; 60 from eight to twelve; and only 5 above twelve years. Of these 132, 6 have fathers only; 59 have mothers only ; 64 have both parents; 3 are orphans; 19 have been deserted by fathers, and 32 are illegitimate. Table showing Progress of the Juvenile School of Industry. Average Average . Got Year. Watenditce: Total cost. Food. Earnings.| Net Cost. Situations. £ s. d. Ss: d. Sijcd> £ os. d. 1845-46 57 47 8 3.7 4 8 5 319 3 26 1846-47 75 ry (ale 3 6 8 Beds ACSA 4 6 1847-48 84 a a 3 210 4 0 rome 15 1848-49 94 3,169 26 4 2 0 314 9 8 1849-50 85 40 0 24210 2 10 S37 2 10 1850-51 95 ended, 1 14 10 3 0 S47 rf 1851-52 94 (A BANS} je | ae 6 9 315 6 12 1852-53 79 319 1 217 6 3.4 315 9 15 1853-54 73 4 310 3.8 9 ak 316 6 1l 1854-55 71 4 14 10 5 eee a) 7 0 4 710 9 1855-56 79 4 6 4 3 6 5 4 3 ra a | 8 1856-57 73 4 810 3.0 7 5103} 4 2 14 15 1857-58 81 4 6 4 2129 4 53] 4 1 103 9 1858-59 120 OMe eee ee es 2103 ]} 3 0 3} 12 N.B. The higher earnings of the years 1846, 1854, and 1855 arose from the boys being on the whole somewhat above the average age. The last column shows only those who have obtained situations direct from the school. Table of Ages of Girls at Female School, December 1845.—Number on Roll 64. EIBGCE fw TY EATS.. 4. 6 acckrichshepiyer 2 Between 7and § ..........6. 11——-13 “3 Sand 9..... stclsicie sone 5 Oand lO va wine caro ats 12 Fe eh O ANG Aiiss. th this wen cegets 13 ser Pel ane Seas. casts amacretate oF Ran | IZA Yd | A ee ee ee 6 Above AB isch. cotati =O Thus 13 were under eight years of age, and 51 from eight to thirteen ; 30 had both parents alive; 5 had fathers only; 26 had mothers only; and 3 were orphans. December 1846.—60 on Roll. aden A" 7 years) 4. eas. 88 ee Between 7and 9...........- 26 pa Stand A Hoss Laas 22 SpA oscccia as Siorptenets 10———60 62 REPORT—1859., Thus 2 were under seven, while 48 were from seven to eleven years; 25 had both parents alive; 24 had mothers only; 7 had fathers only ; 4 were orphans ; and of the 25 who had both parents alive, 6 had been deserted by fathers,—making 30 dependent on mothers only. ae weer oS Total cost of each pupil ........ 3 18 10 Earnings Ae On Rees ee 0 6113 Net cost Eh ss hele Geers 3 11 114 In 1846 the school was divided into two, viz. Sheriff Watson’s Female School of Industry, and the Aberdeen Female School of Industry. Sheriff Watson’s Female School in 1851 had 71 on the Roll, of whom 58 were under eleven years of age, and the cost per head £2 8s. 6d. per aunum. In 1858-59 the average number on roll was 633, while the average attend- ance on week days was 61,—a result rarely attained in any school. The average attendance on Sunday was 55,5. Ages of 70 on Roll, 1st April, 1859. Ages. Time at School. Under’ § years .,,,., 8 Under year ..,... 34 » =) S Sy) an ae 18 na, We mae exe Vaiss Sept se OMe e eae at LT ayy EE hiss | ee eth 10 PE es ORS a URS rae Mere, oe 4 af Rie « “Gy OO ae aie 9 oo BD» 4 Pe a ale mer oe 8 ae. 8 Dh on 2 AO fp hacks eu Of these 70, 36 have both parents alive, and of these 12 have been deserted by fathers; 1 by her mother; and 1 by both parents; 27 have mothers only alive; and 1 is an orphan. 27 left during the year; 8 required at home, 7 to domestic service, 4 parents leaving Aberdeen, 2 in bad health, 3 to manufactories, 2 improved circumstances of family, and 1 to Orphan Institution, LM Gh The cost per head for food was.......... 2 7 74 The total’ cost. per head: 2.32. .4.005056 318 54 dhe eargings yer Head *.'ss'sece seucrspaaae, ee PICUSEOREY Se eters teers adr eg ss caterer 5°18" J Aberdeen Female School of Industry. In 1851 the number on roll was 77, of whom 63 were under twelve years of age; 18 obtained situations as domestic servants during the year ; and the average expense of each was £3 8s. per annum. In 1856 the number on roll was 81, of whom 59 were under twelve years of age. During the year 14 went to domestic service and 5 to other work, and the full number on the roll was usually present at school. 3 were orphans; 2 deserted by fathers; 20 had mothers only ; 23 both parents alive ; and 18 illegitimate. In 1859 the number on roll was 96, of whom 53 were under ten years of age; 36 from ten to twelve; and 7 from twelve to fourteen. 24 obtained domestic service, and 7 other employment. 1 was an orphan ; 8 deserted by fathers ; $4 fathers dead ; 9 mothers dead ; 3 mothers dead and deserted by fathers ; 1 deserted by both parents; 25 both parents alive; and 15 illegitimate. Average cost of each child per annum £4 7s, 113d. Average attendance 93. UPPER SILURIANS OF LESMAHAGOW, 63 Proceedings of Child’s Asylum, opened December 1846. Boys. Girls. Total. Dec. 1846 to Dec. 1847 police brought up.... 56 39 95 » 1647 °° ,, 1848 ” nee a 16 46 » 1646, | 1849 9 aeicecpe 6 28 3 1849s, ~ «1850 » Hic cy ce (9) 2 12 », 1850 » . 18d] » . 1] 6 ay Making in five years 129 boys and 69 girls,—in all 198. It soon became apparent that the operations of police were so effective, that they must soon cease to supply sufficient numbers of pupils to the schools, and the Child’s Asylum Committee resolved to receive and investi- ate applications from the parents or friends of neglected juveniles. The first four years of this mode of proceeding gave the following results: Boys. Girls. Total. 1848. Applications on behalf of ....,..... 92 57 149 1849. ” are Bley oaicane 103 32 135 1850. ” sete 26. aeteit tee 7 82 30 112 1851. ” PR Mee ii Real ane 88 21 109 The general result of the first five years’ operations of the asylum is that 703 cases of neglected children were investigated by means of it, most of whom were sent to one or other of the industrial schools; e. g. in 1851, of the 109, 54 boys were sent to the boys’ school; 42 boys and girls to the juvenile school; 2 to Inspector of Poor; and 10 refused as unsuitable. The Child’s Asylum continues in constant operation, and a full record is made and preserved of each case ; but no reports or tables have been printed since 1851. On the Upper Silurians of Lesmahagow, Lanarkshire. Tue interest excited at the Glasgow Meeting, in 1855, by the announce- ment of a highly fossiliferous tract of Upper Silurian strata in the parish of Lesmahagow, and by the exhibition of their new and rare fossil forms at the Leeds Meeting in 1858, induced the Association to vote the sum of £20 towards the further exploration of these beds by their original discoverer, Mr. Robert Slimon. This sum was placed under the direction of a Com- mittee consisting of Sir Roderick I. Murchison, Mr. Page, and Professor Ramsay ; and under the condition that the specimens should be given in the first place to the public Museum of Edinburgh, and duplicates thereafter to the Museums of Economic Geology in London and Dublin. In terms of this grant, the Committee, through their resident member, Mr. Page, have now to report :— That during the past summer Mr. Slimon and his son have shown great industry in exploring the various sections exhibited in the channels of the Logan, Nethan, Priesthall Burn, and other streams that flow from the Nitberry Hills, and cut through the strata in question. As these strata consist for the most part of brittle slaty mudstones, wholly unfit for any economic purpose, and rendered still more brittle by the intersection of numerous felspathic dykes, there was no other mode of exploration than by quarrying directly for the fossils, and this at as many points as were accessible, and as far as the limits of the grant would allow. 64 REPORT—1859. The result of these operations have been to exhibit still further the highly fossiliferous character of the Nitberry Silurians, and to give ample indication of a very varied and curious crustacean fauna altogether new to Palwonto- logy. Molluscous remains of well-known Upper Silurian genera have also been obtained in sufficient numbers to prove the affinities of the beds; and indications of both an aquatic and terrestrial flora seem by no means rare throughout the strata. Another fact fully established by the exploration is, that while the lower beds exhibit the closest paleontological relations with the Ludlow beds of England, the upper pass insensibly—and without any marked boundary, lithological or palzontological—into flaggy tilestones which are the un- doubted equivalents of the lowermost Old Red of Forfarshire. The specimens obtained during the explorations have a threefold value :— Ist, as proving the true Upper Silurian epoch of the Nitberry strata, and thus affording a clue to the investigation of other Sub-Devonian tracts in Scotland which are yet but imperfectly understood; 2nd, as adding new forms to the life of a former epoch, and thus extending the boundaries of our zoological knowledge; and 3rdly, as enabling the Government palezonto- logists, who have recently published their first monograph on the Eury- pteride, to understand more clearly the nature of this curious family of Crustaceans, and to correct what must now evidently appear as misinterpre- tations of their structure and affinities. Arranging in order the fossils obtained by Mr. Slimon, we have of PLant REMAINS :— Numerous fucoidal impressions. Calciphytes. Lepidendroid stems evidently in fructification. Mo.tusca :— ‘Modiolopsis, 2 species. Platyschismus, or Trochus helicites. Nucula. Lingula cornea. Orthoceras. Pterinea. Avicula. ANNELLIDA :—Spirorbis Lewisii. CRUSTACEA :— Fam. Eurypteride. Pterygotus bilobus. » perornatus. ” punctatus. rh acuminatus. Eurypterus lanceolatus. » pygmeeus (?). Stylonurus spinipes, and another. Fam. Nebaliade :— Ceratiocaris, several undetermined species. Fam. Limnadiadee :— Beyrichia. Undetermined organisms, apparently Crustacean or Amorphozoan. In none of the beds examined, nor during the whole of Mr. Slimon’s pre- CHEMICAL EXAMINATION OF ROCKS AND MINERALS, 65 vious explorations, which have extended over several years, has there ever been detected any trace of an ichthyolite—tish-seale, fin-spine, or tooth—a noticeable fact, considering the highly fossiliferous character of the strata, and the indications that many of them give of littoral as well as of deep-sea conditions of deposit. Looking at the paleontological value of Mr. Slimon’s discoveries, and the additional interest they have conferred on Paleozoic Geology, your Com- mittee would respectfully urge upon him a continuance of his labours, con- joined with the hope that, if at all compatible with the other requirements of the Association, a further grant of say £10 or £20 should be made to assist in so desirable an object. Report on the Results obtained by the Mechanico-Chemical Examination of Rocks and Minerals. By Aueuonse Gaces, M.R.I.A., Curator of the Museum of Irish Industry. I nap the honour of bringing before the Section at the last meeting of the Association at Leeds, a short paper entitled “ On a Method of observation applied to the study of Metamorphic Rocks, and on some Molecular Changes exhibited by the action of Acids upon them.” The principal feature of this method of examination consisted in exposing thin plates of rocks, or crystals cut in certain directions, to the slow action of solutions of acids or alkalies of different degrees of concentration, under such varied circumstances as the special characters of each rock may suggest. The general result of this action was the gradual removal of some or of all the bases, a residue being left, the structure and composition of which indicated the mode of formation of the original rock. The idea of submitting rocks or minerals to the action of various solvents is not new. But hitherto experimenters have operated upon the powdered mineral. I operate upon fragments which exhibit not only the chemical constitution of the substance under examination, but what is in many in- stances of still greater importance, the mechanical constitution also. An example will explain still better the difference. If we powder a piece of alum and put it into water, it will dissolve, and so far as the appearance presented by the powdered mass, uniformly. But if we take the same piece of alum, and instead of breaking it up, grind a flat surface upon it, and place it, as Daniel did, in water with its polished face downwards, the water will act upon that face very unequally ; after a time erystals will stand out in relief, and what looked like a homogeneous ery- stalline mass, will be shown to be made up of a confused mass of interlaced crystals cemented together. Observers have no doubt dissolved minerals in fragments as well as in powder, but they have not, so far as I am aware, done so with the object of studying the peculiar mechanical arrangement of the components of rocks, and certainly have not done so as a methodical system of examination. If, as Daniel's experiments show, we may learn much regarding the molecular structure of even a crystalline mass of a homogeneous substance by the manner of dissolving it, how much more so must this be the case with such complex mechanical mixtures as most rocks are! Before detailing the experiments which I have made during the past year, I may observe, that although the application of this method of examination (which, for want of a better word, we may call mechanico-chemical) is limited to a certain number 1859. F 66 REPORT—1859. of rocks, it may be advantageously employed as a kind of preliminary quali- tative analysis, in the case of the majority of sedimentary rocks, whether meta- morphic or otherwise, before reducing them to powder, in order to analyse them by the ordinary method. The slow and prolonged action of acids on minerals or rocks composed of a mixture of minerals, or even those mainly com- posed apparently of one mineral, enables us sometimes to discover substances which would otherwise have passed unnoticed, and the constituents of which would consequently be confounded with those of the rest of the rock. The number of rocks which resist without decomposition the prolonged action of acids such as HCl and HO SO, at various temperatures, up to their boiling-point, is extremely limited ; and this is especially the case if fragments of rocks be subjected to the alternate action of the two acids. Those espe- cially which have undergone a slight alteration, such as the commencement of the formation of hydrated minerals, always yield to such treatment. A great number of rocks, consisting of aluminous silicates or silicates of lime or magnesia, frequently leave, after treatment with acids, skeletons which show us the manner in which many minerals may have been decomposed, the residues which they left often serving as the basis of new formations. In examining calcareous rocks containing such skeletons, it is necessary to use dilute acid solutions, sometimes indeed extremely so; as concentrated acids might in many instances decompose the skeletons, especially if they appeared to contain hydrated silicates. The rocks which I have submitted to examination since the last meeting of the Association may be classified as follows :— 1. Comparative examination of the residues of Permian magnesian lime- stones from ten localities. 2. Comparative examination of the magnesian limestone of Howth, Co. of Dublin, contrasted with those of the Permian localities. 3. Magnesian limestone conglomerate from Downhill, Co. Londonderry. 4, Examination and analysis of a pseudo-dolomite, found at the junction of the trap and carboniferous limestone, at Stone Park Quarry, 2} miles north of Six Mile Bridge, Co. of Limerick. 5. Experiments on the composition and structure of the residues obtained from the Calp or middle limestone, Co. of Dublin, and of the lower limestone shales of Drogheda. 6. On chloritic slate, and metamorphic limestone derived from it. 7. Ona metamorphic limestone containing garnets reposing on the granite near Gweedore River, Co. Donegal. 1. Magnesian Limestones from Permian Localities.—There appears to me to be considerable confusion in the minds of some geologists regarding what are called Magnesian Limestones. The terms Dolomite and Magnesian Limestone, in the sense in which they are sometimes employed, seem to imply a similarity in the mode of formation. This is, however, far from being the case. Most limestone rocks, whatever may be their origin, contain some magnesia; and even recent corals and marine shells have been found by the investigations of Dana and Forchammer to contain some. I have no intention to propose a nomenclature of magnesian limestones; I merely wish to trace the distinctive characters of some of those rocks by means of the residues which they leave when treated with acids, and which are often the only witnesses which could instruct us as to the mode of their formation. Some of these residues are very characteristic ; thus the Permian are ochrey, and always contain fragments of hyaline quartz, some- times rounded on the angles. Those, on the contrary, derived from mag- nesian limestones formed either by infiltration or in a tranquil medium, and CHEMICAL EXAMINATION OF ROCKS AND MINERALS. 67 Tabulated Statement of the Characteristics of the Permian Magnesian Lime- stones examined, and the Proportions of Residues which they contain. bonate in the Rock. No.| Locality, Description of Rock, Observations. f Lime and Magnesia. Residue Soluble matter consisting chiefly 0 of Carb. —— | 1. |Townland of|Variegated purplish and} 90°70 | 9-30 |Residue of a highly plastic Templereagh.| buff-coloured magnesian ochrey clay of a yellowish limestone breaking with buff-colour, and containing a sharp angular fracture. a fine debris of transparent quartz. 71:65 | 28-35 |Residue consisting of a fer- ruginous clay of a violet- red colour, intermingled with about its own weight of debris of quartz, SS ee ———— 2. |Templereagh. |Magnesian limestone, pur- plish grey, exhibiting over its surface small shining grains of quartz. 3. |Artrea, Co.Ty-|Magnesian limestone of aj 91°30 | 8-70 |Residue composed chiefly o rone. light buff-colour and very small fragments of oolitic structure, transparent quartz, with some opalescent ones also, as large as a pea. Traces of yellow ochre. — |——_——__ ___ eo ee 4, |Yorkshire. |Kidney-shaped nodules of| 98°72 | 1:28 |Yellowish-brown clay and magnesian _ limestone, minute fragments of trans- of a liver - colour: frac- parent quartz, ture highly crystalline. 5. |Durham. Stalagmitie concretions of| 98°34 | 1:66 |Light-brown ochre, with magnesian limestone of some fragments of hyaline a light-brown colour. quartz. 98°70 | 1:30 |Very minute granular frag- ments of quartz, witha light brown-coloured ochre. ————S§ 6, |Durham. Fine-grained cellular mag- nesian limestone of a whitish-grey colour. 7. \From the same|Characters of the rock the ad as} same as the preceding. o. 6. 98:10 | 1:20 |Very minute grains of quartz, with light-brown ochre, 94:45 | 5°55 |Light-brown ochre, with small angular fragments of hyaline quartz. 8. |Cheltenham. |Light brown-coloured pi- solitic magnesian lime- stone. 9. |Sutton _near|Red earthy compact mag- Ashby, N.W,}| nesian limestone. Manchester. 10, |Exhall, Co-|Sandstone formed of fine} 21°53 | 78:47 |If we reverse the numbers ventry. quartz sand cemented representing the sand and by carbonate of lime carbonates, we shall have a and magnesia, magnesian limestone of the same character as No, 9. F2 78:00 | 22:00 |Red ochre, with some fine hyaline quartz sand, 68 REPORT—1859. under the influence of the decomposition of other rocks, contain, in the majority of cases, crystalline substances in a whole state, or partially decom- posed silicates. Having just indicated the comparative distinctive characters of the residues left by the magnesian limestones of different kinds, I will now proceed to describe those of the Permian in detail. The magnesian limestones of the Permian group which I have had an opportunity of examining, leave, when treated with hydrochloric acid, more or less abundant residues, offering the same lithological characters. These residues are ferruginous clay, varying in colour from deep red to very pale yellow. These variations of colour are due to the relative proportions of sesquioxide of iron present, and sometimes to that of manganese also. The residues contained besides fragments of transparent quartz, which may be separated by washing. The oolitic characters which some of those mag- nesian limestones assume are always due to those fragments of quartz, which serve as nuclei around which the deposit of carbonates is formed. The quan- tity of residue sometimes exceeds 30 per cent., and often does not amount to 3 per cent.; but whatever may be the quantity of the residue, its lithological characters remain always the same. The following Table contains the results of my examination of each of the specimens of maguesian limestone from Permian localities. No. 3 in the Table illustrates very strikingly the origin of the oolitic structure in calearcous rocks. When a fragment was exposed for a short time to the action of hydrochloric acid, so as to remove part of the lime, the grains of sand were observed standing in a kind of hollow shell. It differs, however, from the generality of oolitic rocks, in which the grain of sand or matter forming the nucleus is surrounded by concentric layers of calcareous matter. In the rock under notice, the grains of sand appear, so far as can be judged by means of a lens, to have been simply imbedded in the cementing parts. 2. Howth Dolomite The dolomite of Howth, Co. of Dublin, belongs to the carboniferous series, and rests on Cambrian slates. It is of a light yellowish-brown colour and has a compact crystalline texture, with many cavities, however, which are filled with well-developed crystals of bitter-spar. When examined with a lens, it appeared to be formed of a series of irregular serrated layers, sometimes containing oxide of manganese in more or less quantity. On being treated with acetic acid, it divided itself into small granular crystals of bitter-spar, resembling an extremely fine sand. It thus presented all the characteristics of true dolomite. Treated with dilute hydrochloric acid, it left a residue never exceeding 3 per cent., and consisting of a reddish-brown ochrey clay mingled with crystals of quartz, which were separated by agitating the residue in water. They consisted of very fine acicular crystals of opake quartz, having a fibrous. arrangement, the edges of some of the crystals being somewhat eaten away. Washed several times with hydrochloric acid, and then treated with hydro- fluoric acid, these crystals yielded an appreciable quantity of alumina, oxide of iron, lime, and magnesia, a circumstance which suggests that they may be the relics of some augitic or hornblendic rock. The Rev. Prof. Haughton, to whom I submitted these crystals, and who examined them, considered them to be “fibrous quartz, and such as occurs in the minute veins of quartz in the slate rocks of which the Hill of Howth is formed.” What is most remarkable in connexion with those crystals, is the constancy with which the residue is found disseminated throughout the whole dolomitic mass of Howth. CHEMICAL EXAMINATION OF ROCKS AND MINERALS, 69 The composition in 100 parts of the Howth dolomite may be thus repre- sented as follows :— Carbonate of lime...... Rares Tass Sete ea Facets.) TOOT SarHOuALe Of MAPNESA. ais... eee e eee sees eee, 49°610 IETAE, OL ALOU are aie tw ano sp 60,0 oss See e nes gas em leuk MOO , ROO RM achate ts so. 5. a) aia. pins mes. 5181 Bg 0°735 Residue ) Fibrous quartz ....... ee ene isles Peroxide of manganese (in variable quantity). 99°841 3. Magnesian Conglomerate from Downhill, Co. Londonderry.—This rock, which has been improperly called hydrocarbonate of magnesia, is formed of spherical nodules encircled by a greenish paste, composed generally of car- bonate of iron and of a partially decomposed ferro-magnesian silicate. The composition of the part of this conglomerate soluble in dilute hydro- chloric acid varies very much, as does that of the residue likewise. It some- times acquires the character of true dolomite ; and, according to Prof.Oldham, it contains crystals of bitter-spar disseminated through the mass. ‘The fol- lowing Table, containing the results of two analyses of the soluble part, will show the character of the variation alluded to: — I, II. Carbonate of lime .... 63°700 70°863 Carbonate of magnesia . 21°325 17-481 Protoxide of iron .... 3°400 1111 HEMGUCK sens scniscicee 8815 0°896 Rk icles asin 2-700 (by difference) 9°G00 (experimentally), 100°000 99°951 The following results, obtained by Dr. Apjohn, bear out what has been said above, that the proportion of magnesia to lime sometimes reaches that ob- served in true dolomite :— Carbonate of lime .....e-es+5++- sible ote Chics steed ee AOS Carbonate of magnesia .....+ +e ee eres ee ee ee eens 38°23 Carbonate of iron ..... NC OR eee SY. sone 5°93 Silex and loss ........ Libin/dteseeateks Rtek Sarote ereraiteve "5 oie 0°96 100°00 The residue left after the dissolution of the carbonates in dilute hydro- chloric acid, is generally of a variable greenish colour and a spongy texture; it contains a quantity of water, and also some organic matters. The following Table gives the results of analyses of three specimens of this residue ;— I. II. III. RL CUM so reae aiScrchenule o10ic) syi%a je 40°371 60°725 70°532 Magnesia...... Satori iil 13°719 5°656 4°259 ETC hohe aca) oxchehs:sfel.s «xe i6ie-n — 0'251 _—_— Protoxide of iron.......... 6913 5461 5218 PMLA TALIA ccc Pe) ata phous. vu moeveue,8 xs 0:216 D557 0°4:73 Water and organic matter, ; t 2 &c. by direrence Ss san \ oe os oti 100°000 100:000 100:000 In examining one of those residues with a lens, I found a perfect octahe- dron of red oxide of copper, 70 REPORT—1859. 4 Pseudo-dolomite-—This rock was found, according to Mr. O‘Kelly of the Irish Geological Survey, at the junction of the trap and carboniferous limestone at Stone Park, 24 miles north of Six Mile Bridge, Co. of Limerick. It presents the appearance, at first sight, of the dolomitic limestone of Howth and other carboniferous localities; and isof a brown colour passing into yellow, being traversed by a great number of fine veins of calcite. It is covered by an ochrey substance, similar to that which results from the decomposition of the trap. It left, after digestion with dilute hydrochloric acid, a residue preserving the form of the piece of rock; it had, however, so little cohesion, that it separated into grains on the slightest agitation. The composition of this rock may be represented thus :— GarbonatevOr lime. c aes. c6 ses helene tae tt be bagle cep DP OZO Carbonate Of Magnesia .. 6... ossccstse- eo surewe 5°892 Warbonate OL ILON snc ck ie ss bade cee slere t Pek 7°590 EAN UTNE SEY so ¥Ste aE SO eS NES oe a ROS Ee IE 0:590 IWRCCK ee borates foresee heict sts ge Maes cote nS 92°820 WelspathiC FESIANE pac icks oss. tie ons a sls angst pas 25°780 100°292 The residue, when washed and dried, exhibits under the microscope cellular fragments of an apple-green colour, analogous to some residues derived from the decomposition of felstones and greenstones. With this substance were also found grains of hyaline quartz. This residue is attacked by boiling sulphuric acid, which leaves the quartz debris untouched. Analysed in this way the following results were ob- tained :— Silica and fragments of quartz .................. 73°491 Alimima #00 Aste hated sh eS lies aes 9°467 PePOe Ye ele Ree ete 4°127 GAM OS SHS. | oie c de dees See eh a Rie ere PRE AS. Oe Wianesia ss hee ssa he Sie Fis oe aw Rp Re ee ae traces MAG GHB G8 rh ele eres ae be eae Pn ip sae ohana BAS. htt 55a SEO Rec CaS Rated ee ee ee 1°451 Water... 5 oc 56 ROMER Ct anette. ws iiss 6E02 99°867 It results from this analysis, that the residue is a felspathic mass, disintegrated by some mechanical means before it became enveloped by the calcareous matter which forms the existing rock. Unless this were so, the quartz could not be found in a fragmentary condition. If the rocks which formed the subject of the preceding observations were analysed in the ordinary way, by crushing them to powder, all the evidence regarding their origin and probable mode of formation, which has been so well exhibited by slowly operating with acids upon fragments, in such a manner as not to break up or alter the foreign substances enclosed by the carbonates, would have been obliterated. Where dolomitic rocks are asso- ciated with basalt and other igneous rocks, and enclose silicated minerals, such as tourmaline, tremolite, &c., which are characteristic of igneous rocks, geologists are able to recognize at once the connexion between the dolomites and the igneous rocks; but in very many cases dolomitic rocks bear no such visible evidence of relationship to other rocks, and yet many have been formed by their metamorphosis. The long list of constituents, such as CHEMICAL EXAMINATION OF ROCKS AND MINERALS. 71 alumina, protoxide of iron, silica, &c., which is given in the Tables repre- senting the analyses of limestones and dolomites, conveys but little informa- tion as to how they came there. On the other hand, by studying the nature of the residue left by the magnesian limestone of the Permian formation, we have evidence that they were formed by single deposition. Again, the residue of delicate fibrous quartz which is found in the Howth dolomite, if not characteristic, is at least indicative of change subsequent to its deposition, a conclusion strongly supported by the cellular structure of the rock, which, according to Elie de Beaumont and Morlot, affords incontestable proof of alteration subsequent to the deposition of calcareous rocks. The dolomitic conglomerate of Down Hill and the pseudo-dolomite belong to a different class of phenomena. In the former case we have a species of conglomerate formed of chalk and decomposing amygdaloidal basalt. The calcareous part became more or less dolomitic, crystals of bitter-spar being sometimes formed ; the magnesia forming the essential part of the residue is evidently the source of alteration, and accordingly varies, as is seen in the Table, and sometimes even wholly disappears. ‘The protoxide of iron also is gradually removed along with the magnesia, and so completely sometimes that only a siliceous skeleton remains. The previous analyses of the mass give us no clue whatever to this mode of formation, and indeed do not afford any evidence whatever of the difference between it and any other kind of dolo- mite. The character of the residue fully explains the history of the pseudo- dolomite. It consists of the relics of some felspathic rock enveloped in a mass of carbonate of lime, magnesia, and iron, themselves the products of decomposition of local trappean rocks. So far as the individual rocks ex- amined are concerned, the results are of course new; but the formation of dolomites of the character just described has been long since known and their relationship to igneous rocks clearly indicated; I do not therefore bring forward the preceding examples because they contain any general fact hitherto unknown, but because they serve to illustrate the true method which should be followed in the analysis of rocks. To complete the illustration, it would be necessary to contrast the results obtained by means of it, with the many elaborate tables of analyses annually published, and which, so far as the explanation of geological phenomena is concerned, are wholly value- less, however admirable they may be as specimens of skill of the analysts in separating different substances from one another. &. Calp and Lower Limestone Shales—The mountain limestone dissolves in acids without leaving any earthy residue ; and when the solution is filtered, only a little charcoal remains on the filter. But when portions of the in- termediate rocks are treated with acid, they leave residues more or less abundant, consisting of sand, clay, or carbonaceous matter and iron pyrites. These residues, disseminated through limestones, completely alter their litho- logical appearance, and communicate to them different physical properties ; in this way are formed the various limestone-shales, grits, &c. of the car- boniferous formation. ‘These calcareous substances, when digested for a longer or shorter period according to circumstances, in water slightly acidified by hydrochloric acid, are easily penetrated in the cold, and the whole of the carbonate of lime is dissolved out. The skeletons which these different deposits leave on being thus treated, indicate very clearly, as in the case of the Permian magnesian limestones, some of the conditions under which the rocks have been formed. A specimen of hydraulic limestone from the envirous of Milltown, Co. of Dublin, treated in the manner just described, gave— 72 : REPORT—1859. Carbonate ‘of lime’... 6 i eed Sh ee GIAO Carbonate of magnesia........... Pa OA aN .. traces Clay Be. Se Fe ea a wi Sard ss eg oe Th oe IT, OE EE aoe fate Carbonaceous matter, pyrites and amorphous sulphide } 0°50 Of iron? PA Pek Set Ae ee ce oh ee ty tee 99°65 This limestone, which is very hard and has a conchoidal fracture, owes the physical properties which distinguish it to the sandy residue forming its skeleton. The latter retains the external form and appearance of the original rock; and even fossil-casts may be recognized and determined. If the skeleton be ignited, the carbonaceous matter is burned away, leaving the cast of the fossil perfect. The skeleton thus exposed represents the sand of the original sea-bottom prior to its infiltration with calcareous matter. When the quantity of argillaceous matter equals that of the carbonate of lime, and especially when the carbonaceous matter is present in a consider- able quantity, this caleareous residue presents all the character of a true mud. This is the case with the lower limestone shales from the neighbour- hood of Drogheda, which may be represented by the following composition :— Carbonate of lime with carbonate of magnesia ...... 47°10 Residue of clay and sand containing iron pyrites .... 47°75 Carbonaceous matter ................ oneee oes 51s 100-00 This residue, and indeed all the similar beds belonging to that formation, contain a good deal of iron pyrites and sulphide of iron in what may be called an amorphous state—apparently a proto-sulphide, as it evolved sulphuretted hydrogen on being treated with acids; both these are included in the clay and sand, and partly in the carbonaceous matter. I may here observe that the quantity of residue, and of carbonaceous matter, varies in different parts of the rock from the same quarry. Thus a specimen taken at a short distance from the locality of the last specimen had the following composition :— Carbonate of lime with carbonate of magnesia ...... 55°40 3 Clay and sand with pyrites.............. 36:00 Residue Carbonareous matter 1. PI. er oe 100:00 In some of these consolidated muds the lime is almost wholly absent ; the lithological character of the residues, however, remains constant. The sand separated from the clay is extremely fine when observed under a strong lens. The analysis of some of these residues may perhaps serve to trace the source from which they were derived. I have already alluded to the existence of two compounds of iron with sulphur in these beds; and I may here remark that the characters which the lower limestone shales, as for instance that of Drogheda, present, appear to offer an explanation of the circumstances under which these sulphides were formed. Weare daily witnesses of the fact, that under the influence of water and organic matter, and exclusion of air, sulphates dissolved in water are reduced to the state of sulphides, which convert the salts of iron in contact with them into sulphide. The sulphide thus formed is amorphous, as may be observed in the black mud which is found under the pavement of streets, and which evolves sulphuretted hydrogen. Now the mud from which these CHEMICAL EXAMINATION OF ROCKS AND MINERALS. 73 limestone shales have been formed, was one in which animal and vegetable substances abounded ; for they are full of fossils, and the carbonaceous matter is derived from their decay. I may add that many of these fossils are entirely covered by pyrites. - The formation of bisulphide of iron appears to require an excess of sulphur, and would naturally be most readily formed wherever there was an excess of animal organic matter,—a supposition which is supported by the fact recorded by Mr. Pepys*, and cited by Sir Charles Lyell in his ‘ Manual of Elementary Geology.’ It must be admitted, however, that iron pyrites is found in other rocks belonging to the carboniferous formations almost or wholly free from organic matter. The existence of crystals of iron pyrites in granite and trap rocks under circumstances where it would be difficult, if not impossible, for organic matter to intervene, show that that mineral may be formed in various ways. It is worth while remarking, however, that crystalline sulphur has been frequently found in mountain limestone, in which there is not much organic matter. Had iron been abundant in the neighbourhood, this sulphur would doubtless have been converted into pyrites. 6. Chloritic Slate and supposed Metamorphic Limestone derived from it.— The ordinary mode of analysing rocks gives no assistance whatever in de- termining the origin of rocks metamorphosed by igneous agency ; it does not even enable us to determine positively whether a rock has been metamor- phosed by heat or not. The remaining experiments which I have to describe were made with rocks which are generally assigned to this class, and which therefore afford examples of the advantages which may be derived from the employment of the method of examination which I have pursued. The rocks which formed the subject of experiment were, a specimen of altered chloritic slate, and two specimens of what is usually considered as meta- morphic limestone. Beds of this class are found in the N.W. of Ireland, sometimes resting on granite, and always associated with such rocks as gneiss, mica-schist, hornblende slate, &c. I think I have established an interesting relationship between one of those beds and a chloritic schistose rock, which, if it be not wholly opposed to the igneous netamorphosis of the calcareous rock, undoubtedly proves that it could not have been subjected to a very high temperature. Before describing the calcareous rock alluded to, it is necessary to give an account of the chlorite schist, and the results of my analysis of it. The rock, which contains some crystals of augite or hornblende and magnetic iron, oc- eurs in the Townland of Cavan Lower, half a mile east of the town of Stra- norlar in the Co. of Donegal. It effervesces with acids, as most rocks of a similar character do; and when digested with them, the micaceous part is partially attacked. On being boiled for some time with acids, the chief part of the chloritic and other minerals separate from the quartz. Here an im- portant problem suggested itself, namely, in what state did the quartz exist ? Was it formed in the rock by the action of the heat, that is, did the original rock separate under the influence of heat into chlorite and quartz? or was it originally composed of quartz and some cther substance, which alone changed into chlorite ? With the view of attempting a solution of this problem, which applies equally to most kinds of schistose rocks, some thin plates of the schist, carefully detached from different parts of the rock, were treated by diluted hydrochloric acid until every thing soluble was dissolved out. The plates were then repeatedly submitted for some time to the successive action of * Geological Transactions, vol. i. p. 399, First Series. 74 ead REPORT—1859, boiling hydrochloric and sulphuric acid, care being taken, however, to avoid a rapid ebullition, in order not to break or deform them. This treatment was continued until almost every thing soluble in acids was removed. ‘There then remained a residue of beautiful hyaline quartz fragments enveloped in semi- transparent nacreous crystalline-looking scales. These scales being the sili- ceous skeletons left by the foliated chlorite, they dissolved in caustic potash ; so that after a few successive treatments with acids and caustic potash there only remained quartz debris, some of the grains still bearing the impression of the mineral substances which had adhered to them. Before treating the siliceous residue with caustic potash, the nacreous scales and quartz were so intimately mingled, that at first sight it would be difficult to say whether the latter occurred as fragments, or in an unaltered crystalline state. Treatment with caustic potash removes a!l doubt, however, on this subject. The following are the results of an analysis of the chloritic slate :— Alkalies (potash) ..........64.. sa kb Obes teres |. eee NIABRENE ass cee es Stare gehts Becks a ine erate tare 5°439 UAB) coy wos Beare ee Sie acc cht at ¢ sales wri aaa 0°965 Protoxide of iron and a little sesquioxide of iron } 9-064 derived from the magnetic oxide............ Jeu hy 12 agora acl deg SARA Pa ar yr age sr 2 Seabee get 7°360 Wylen tod UHAte SCs; keveerbis sss st eeticc ee Olgas WAGED oa bas Ves a bag ods os SCAT ERE 2862 CArOOHAte OF WMC ees. cess he bbe ns he os bees os 11°081 Carbonate of WMabnesig.. 1.655 es eee oe oe os pss gee 100:102 The ratio of the oxygen in the protoxide bases existing as silicates in this chloritic slate is to that in the alumina as 4°464 : 3°440, that is, there are four equivalents of protoxide bases to one of alumina, which is exactly that in typical chlorite of the formula 4(RO, SiO,) Al,O,, SiO,+3HO. The water in the slate, however, would only correspond to two equivalents; but, on the other hand, the quantity of water in chlorite is subject to vary, and some analyses have been recorded in which the water does not exceed two equivalents. The carbonate of lime or magnesia has no doubt been formed by the decomposition of augite or hornblende. From this it would appear that the original material out of which the chloritic slate was formed, consisted of a caleareo-magnesian slate-clay or shale intermixed with hyaline quartz de- bris, that is, a rock resembling in composition rich clay marls. Having thus ascertained, with considerable probability of truth, the origin of the chlorite, I shall now endeavour to show that the subsequent decom- position of part of the chloritic rock may have furnished materials for the formation of a rock of a totally different character, which is found in the same parish, and about three miles east of the locality from which this schistose rock was obtained, or about two miles to the west of Castlefinn (both local- ities being north of the river Finn). It is marked as metamorphic limestone on Sir Richard Griffith’s Geological Map of Ireland. It has a saccharoidal structure, and a greyish white colour, the grey tint being due to micaceous scales of chlorite which are disseminated through the mass, together with some small crystals of magnetic and common iron pyrites and debris of | hyaline quartz. A fragment of this rock digested in dilute hydrochloric acid, left a residue analogous to that left by the schist when treated in a similar manner. The residue consisted of debris of fragments of hyaline quartz, sometimes agglo- CHEMICAL EXAMINATION OF ROCKS AND MINERALS. 75 merated together and intermixed with fragments of the rock more or less decomposed. The crystals of pyrites which occur in the residue are always cubes with perfectly sharp edges and angles, the latter being some- times truncated. ‘There is every reason to suppose that these crystals were formed subsequently to the interval which gave birth to the limestone. Some of them were found in the midst of the quartz debris ; and one of them consisted of a kind of twin parallel to the faces of the cube, the two halves being, however, separated by a portion of quartz; one half had its edges truncated and the other not. They had thus submitted to the conditions imposed by the medium in the midst of which they were developed. The following are the results of an analysis of a specimen of this lime- stone :— WarBOMBER GE IMNG. Foo bias stoves sone ceinn sess ahityl LOO! Carbonate of magnesia...... aie tains OB ay 32, PAAR OOO Peroxide of iron and alumina ... .....06..-2005- 1°583 Residue consisting of chlorite, magnetic, and ole 21-356 mon iron pyrites and debris of hyaline quartz. . 99°912 It results from these observations that this metamorphic limestone should be regarded as derived from some of the materials of the schist above mentioned. For we may, so to speak, follow the passage of the mica-schist from the point where it does not effervesce with acids, into metamorphic limestone still containing all the essential parts of the schist. If we suppose that this limestone had been subjected to a high temperature, the quartz should have combined with the bases. The crystals of pyrites disseminated through the mass, as well as the position which they occupy, suggest an argument of a similar kind. 7. Gweedore Metamorphic Limestone.—This rock is found associated with mica-schist resting on granite near Gweedore River ; isolated patches of the limestone occasionally rest on the granite, and sometimes alternate with mica- slate. This limestone is saccharoidal, of an aquamarine tint, which is due to the mass of small angular fragments of a green mineral interspersed through it. This mineral often serves as a nucleus to a crystal of carbonate of lime, and is accompanied by small sand-like crystals of idocrase and garnet. Large crystals of garnet are also found in abundance; and from the way in which they are deposited, the rock has a stratified appearance. The faces of the crystals are more or less eaten away, as if they had been weathered. Treated for some time with very dilute hydrochloric acid, this rock gave in 100 parts the following results :— Garnets, idocrase, and green mineral.. 17°16 ) morphous silica.... 6°03 >23°360 Alumina :iviiewy 017 ) Carbonate Of li fo. iiss cee ee 75°250 Carbonate of magnesia ..........+.-.--5- Alumina and oxide of iron soluble in acids ........ O0°512 Weiter. FEES TV e8 wah Eo Se (undetermined) 99°732 If a fragment of this garnet limestone be left in very dilute hydrochloric acid until the whole of the carbonate of lime be removed, the garnets will be found imbedded in nearly pure amorphous silica, which readily dissolves in a weak solution of caustic potash. This siliceous paste is obviously the Residue consisting of ) 4 76 REPORT—1859. skeleton of a former rock. In the generality of instances silica is dissemi- nated through the mass, and then does not form a coherent skeleton, so that the garnets, instead of being surrounded with the amorphous silica, are only coated on some sides with a siliceous film. Cases also occur in which there is no silica, and the limestone contains only a small quantity of the above mentioned green mineral. In fact every analysis of the rock will give a different result as regards the quantity and nature of the residue. The analysisof the green mineral was attended with great difficulty in conse- quence of the fine state of division in which it occurred, besides being mingled with idocrase and garnet debris nearly as fine as itself. A small quantity of it, picked out with the aid of a lens, yielded the following results:— MES dC op sas ceed ecneess hlouolencieed fealeits 26°183 Miaemnesia -.intetere ae of asst sts Pe 8°825 Protoxide of iron. .............- 10°576 Alumima-23 «2%. 22055 OBIE HE! 3°750 Silica Ae yee 1h 7 Gt Beane se 4.9°641 Witerert munities da sclsionies st fae 1:025 100:000 These numbers show that it is an aluminous augite, or more properly an augite and garnet compound, corresponding in a most striking manner with one from Fassa analysed by Kudernatsch*; the sum of the oxygen in the protoxide bases being 13°360 for the green mineral, and 13°658 for the spe- cimen from Fassa. As broken fragments of minerals cannot have been formed by the action of heat upon a sedimentary limestone, the fragmentary state of the green augite, idocrase, and garnets prove that the rock under discussion has not been metamorphosed by heat, On the other hand, the existence of an enve- lope of soluble silica surrounding some of the garnets, seems to show that anterior to the formation of the new limestone rock, one existing of silicates must have existed there. Experiments to determine the Efficiency of Continuous and Self-acting Breaks for RailwayTrains. By WiuL1AM FarrBairn, F.R.S. Or late years various improvements have been introduced upon railways to diminish the dangers of travelling, and attention is now specially directed to the increase of the retarding power for trains by various kinds of breaks. From an early period in the history of railways it was seen that few objects were more important for ensuring the security of passengers and reducing the loss of time occasioned by stoppages, than the attainment of some means of destroying the momentum of trains with ease and rapidity, that is, in the least time and in the shortest distance. The less the time requisite to break a train, the longer the steam may be kept on in approaching a station, and the less is the loss of time in stopping; and the shorter the distance in which a train can be brought to a stand, the less danger is there of collision with obstructions on the line perceived not far off ahead. It is already allowed by many of those connected with railways, and has been expressly stated by the Lords of the Committee of Privy Council for Trade, that the amount of * Gmelin, Handbuch d. Chemie, Bd, 2. p. 383. 4 Auf, EXPERIMENTS ON BREAKS FOR RAILWAY TRAINS. 77 break power habitually supplied to trains is in most cases insufficient ; and their Lordships enumerate thirteen accidents from collision occurring in 1858, - the character of which they consider would have been materially modified, if not altogethr prevented, by an increased retarding power under the command of the guards of the trains. Upon this subject the most important communication hitherto made has been the Report prepared by Colonel Yolland for the Railway Department of the Board of Trade, and containing a large number of experiments with heavy trains at high velocities. The breaks with which Colonel Yolland experi- mented were those which, as improvements on the common hand break, have hitherto commanded most success. These were the steam-break of Mr. McConnel, the continuous break of Mr. Fay, the continuous self-acting break of Mr. Newall, and the self-acting buffer-break of M. Guerin. The general conclusions to which Colonel Yolland was led by his experiments, resulted in the recommendation of the break of Mr. Newall; and for heavy traffic, a provisional recommendation of the break of M. Guerin. From a misunderstanding caused by this Report of Colonel Yolland, arose the necessity for some further experiments on the similar breaks of Mr. Fay and Mr. Newall; and these I was called upon to arrange and carry out by the Directors of the Lancashire and Yorkshire Railway. I propose to lay before the Association a brief abstract of these experiments, with some remarks upon the conclusions to which they give rise. It will not be necessary here to describe minutely the details of the con- struction of these breaks. They consist essentially of a series of break-blocks acting upon every wheel of the carriages of the whole train or some part of the train, the break-blocks being suspended as flaps, or placed on slide bars beneath each carriage, as in the ordinary arrangement of the guard vans. But whereas it would be both expensive and inefficient to work these breaks with a guard or breaksman to each carriage, both Mr. F ay’s and Mr. Newall’s patents provide for a continuous shaft, carried the whole length of the train, beneath the framing and with suitable jointed couplings between each pair of carriages, so that they may be undisturbed by the rocking motion of the train or the action of the buffers. In this way the whole of the breaks may be worked by a single person at either end of the train, communicating his power to each break through the agency of the continuous shaft. Again, there have been applied, in the first instance by Mr. Newall, and subsequently by Mr. Fay, powerful springs beneath each carriage, connected with the arms of the rocking shaft, by means of which the breaks are made to act instantaneously throughout the train, on the release of a catch or dis- engaging coupling in the guard’s van. The value of this provision for the immediate and simultaneous action of the whole of the breaks, in cases where an obstruction is perceived upon the line, will be at once evident. It is one of the most important features of these breaks. In carrying out the views of the Directors of the Lancashire and Yorkshire Railway Company, it was arranged, in order to test the relative efficiency of these breaks, to have a series of experiments upon the Oldham incline of 1 in 27. On this gradient a train of carriages, fitted with Mr. Newall’s self- acting slide breaks, and a similar train fitted with Mr. Fay’s continuous flap breaks, were started in turn, and after having passed over a measured distance by the action of their own gravity, the breaks were applied and the distance along the incline in which the trains were respectively brought up was care- fully ascertained as a measure of the retarding force of each. The trains employed consisted of three weighted carriages each, and having been placed upon the incline, they were started by removing a stop. Having then 78 REPORT—1859. descended a previously measured distance with a uniformly accelerating velocity, they passed over a detonating signal which conveyed notice to the guard to put on the breaks. Then the train having been brought to a stand, the distance from the fog-signal to the point at which the train stopped was measured, and the train brought back for another experiment. In this way it was easy to obtain an initial velocity of 50 feet a second, or 35 miles an hour before applying the breaks. Unfortunately the day upon which these experiments were made proved misty and foggy with rain at intervals, so that the rails were in the very worst condition for facilitating the stoppage of the train. The significance of this fact will be seen on comparing the retarding power of the breaks in these experiments with those made in fine weather. Reducing the results, we find that the retarding force exerted by each break in terms of a unit of mass, calculated from the distance of pulling up, was equivalent to the numbers in the following Table :— Experiments on the Oldham Incline. Mr. Newall. Mr. Fay. No 0b Sp eee eee Experi- | Velocity of} Timein | Retarding || Velocity of} Timein | Retarding ments. |train in feet} stopping | force of |/train in feet] stopping force of per second. |in seconds.| break. per second.|in seconds.| _ break. 1 25°71 14 1:32 25°71 13 1:91 2 30°00 16 163 30°00 13 1-79 3 37°50 17 1:70 37°50 14 1°84 4 42°85 25 1°69 41°37 15 1:76 5 42°85 14 2°01 40°66 12 2-02 6 48°38 19 1-78 48°38 25 1°72 7 52°94 17 2°04 50°00 tvs 191 Mean...| sscccsaee 21:6 OE dsr oe 19°2 1:85 The general result of these experiments gives a retarding force of 1°74 Ib. per unit of mass for Mr. Newall’s break, and 1°85 for Mr. Fay’s; or in other words, Mr. Newall’s break exerted a retarding force of 121°3 lbs. per ton weight of the train, and Mr. Fay’s a retarding force of 129 lbs. per ton. I afterwards arranged for some further experiments at Southport upon a piece of level rail between that town and Liverpool. The speed requisite in this case had to be obtained by the aid of an engine which was detached by a slip coupling at the instant of applying the breaks. In other respects these experiments were conducted like the preceding with fog-signals, and the time noted by stop-watches. ‘The weather, however, was in this case fine and dry, and hence the following results were obtained in the most uniform cireum- stances. The friction of the train itself, and the resistance of the air, were ascertained to amount with Mr. Newall’s train to 6:4 Ibs. per ton, and with Mr. Fay’s train to 10°4 lbs. per ton. In this case we have a retarding force per unit of mass equivalent to 5°49 Ibs. in Mr. Newall’s break, and 6°7 lbs. in Mr. Fay’s; or in other words, the retarding force of the slide breaks of Mr. Newall, from eight experiments, at velocities varying from 35 to 60 miles an hour, was equivalent to 382°6 lbs. per ton weight of the train. The retarding force of Mr. Fay’s slide break from eight similar experiments, at velocities varying from 33 to 63 miles per hour, was quit to 466° 4 Ibs. per ton weight of the train. - . : 79 EXPERIMENTS ON BREAKS FOR RAILWAY TRAINS. Experiments at Southport. Slide Breaks, Engine detached. Mr. Newall. Mr. Fay. Speed in | Distance of| Retarding || Speed in | Distance of Retarding miles per | pulling up| force of || miles per | pulling up| force of hour. in yards. break. hour. in yards. break. 32°72 562 6°77 35°29 56 7:97 36°73 77 6°28 43°90 98 7°05 43-90 136 5°08 50°00 129 6:94 46:15 1402 5°42 54°54 144 7°40 52°94 2052 4:89 54°54 1612 6°59 54°54 192 4°66 37°89 97 5°30 47°37 2603 _— 60°00 2042 6-30 53°73 222 5°23 60:00 214 6:03 63°16 273 5°55 —_— — — Mean 6°70 Mean...| 5°49 a eel Flap Breaks, Engine detached. Mr. Newall, Mr. Fay. Speed in | Distance of | Retarding || Speed in |Distance of} Retarding miles per | pulling up| force of || miles per | pulling up| force of hour. in yards. break. hour. in yards. break. 50°00 1322 6°75 51°43 1584 5°98 50°00 123 7°28 51°43 1622 5°82 51°43 192 4:93 54°54 184 5°79 Mean... 6°32 Mean...| 5°87 These experiments give for the retarding force of Mr, Newall’s flap break 6:32 lbs. per unit of mass, and for Mr. Fay’s 5°87 lbs.; or in other words, the retarding force of Mr. Newall’s flap break, from three experiments, at velocities varying from 50 to 513 miles per hour, was equivalent to 440°3 lbs. per ton weight of the train. The retarding force of Mr, Fay’s flap breaks, from three similar experi- ments, was 408°6 Ibs, per ton. We may illustrate the general bearing of these experiments by estimating from an average of the whole experiments the distance required to stop a train fitted throughout with these breaks, and detached from the engine. A train would be stopped,— At a velocity of 20 miles an hour in 23:4 yards. ” ” 30 ” ” 529, ” ” 40 ” ” 93°38, ” ” 50 ” ” 1468s, ” ” 60 ” ” 211°5 » This last Table exhibits in a very clear manner the advantages of this class of breaks, in which the whole weight of the train aids in destroying the mo- mentum of the mass instead of the weight of one or two guard vans only. It may be impossible in long trains to apply these breaks to every carriage ; but, at all events, in the ordinary traffic three times the present amount of break power may be employed with ease, = 80 REPORT—1859. On the score of economy also, the system appears to encourage its applica- tion; from experiments which have been made, it appears that the wear of the tyres is far more uniform and equal, because the break springs may beso adjusted as not to cause the wheels to skid. The Manager of the East Lan- cashire Railway states that with two trains running together between Salford and Colne, the carriages fitted with continuous breaks travelled 47,604 miles before the wheels required turning up; whilst an ordinary break van running the same distance had to have its wheels turned up three times in the same period, three-eighths of an inch being taken off each time. Experiments at Southport. Engine not detached from the Trains. Mr. Newall. Mr. Fay. Speed | Distance of|| Speed | Distance of Se IBa is per hour. | pulling up. || per hour. | pulling up. miles. yards. miles. vards, 33°96 1242 31:8 1212 ) |Engine and tender. 37°11 1693 33°96 137 Tender and continuous 41°86 221 | 41°86 19223 breaks applied. 5143 274 Tank engine. It will be observed that on most through lines the trains travel on some portion of the distance at the rate of 60 miles an hour, and in the event of an obstruction half a mile in advance, a collision would be inevitable unless the driver has the power and the presence of mind to act with promptitude. Now at 60 miles an hour there is only 30 seconds, or half a minute, to effect that object, and it is quite impossible to apply the breaks in their present state, before the train, in such a precarious position, is in actual contact. As- suming, however, that breaks upon the principle of Mr. Newall and Mr. Fay were attached to the engine as well as the train, and that the driver had the power of instantaneous application by liberating a spring, it is evident that, instead of the train dashing forward to destruction, the momentum might be destroyed in a distance of less than 500 yards, and that without injury to life or property. Besides, the application of the Electric Telegraph, which prevents on most through lines more than one train being on the line between the stations, is a great additional security, and that, united to the continuous break, applied to the engine as well as the train, would—when united to a more perfect system of signals—render collision next to impossible. Report of Dublin Bay Dredging Committee for 1858-59. By Professor J. R. Kinanan, M.D., F.L.S., M.R.LA_ Tue Dredging Committee, appointed at the Leeds Meeting in 1858, con- sisted of Professor Kinahan, Dr. Carte, Dr. E. Perceval Wright, F.L.S., and Professor J. Reay Greene. Early in the winter of 1858, the author commenced investigations at the - south of the district on the Scallop Bank near Bray, to which three excursions were made with success, as regards the captures made. Early in 1859 aseries of severe gales occurred, which afforded a rich harvest of specimens on the Portmarnock Strand to the north of Dublin; many species of Mol- A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS, 8] lusea, Crustacea, &c., ordinarily of rare occurrence, having been thrown up in abundance living on the beach, betokening a serious disturbance of the banks in the neighbouring seas. The following may be enumerated :— Cochlodesma pretenue, Fissurella reticulata, Emarginula reticulata, Mactra elliptica, Tapes virginea, var. Sarniensis (very abundant), Zhracia villosius- cula, Thracia phaseolina, Thracia convexa (a single valve). Inachus Dorsettensis, Pilumnus hirtellus (chiefly broken), Portunus holsa- tus, Portumnus variegatus, Corystes Cassivelaunus, Nephrops Norvegicus (all broken, but in great profusion), Cribella oculata, Asterias aurantiaca, Spa- tangus purpureus, Thyone papillosa, Priapulus caudatus, &c. The results of these investigations have been all noted, but unfortunately an inflammatory attack of the eyes, of some months’ duration, put a stop, on the author's part, to the completion of the labours which had been com- menced. Dr. E. Perceval Wright in the month of June undertook the particular examination of the district in the neighbourhood of Ireland’s Eye ; the results of his investigation, which are not yet completed, he hopes to include in the next year’s Report. From the materials now at their disposal, your Committee hope next year to be able to present a more systematic Keport, as the results obtained, though important, are not sufficiently numerous to enable them to do so yet; they have therefore to request that the same Committee, Professor Kinahan, Dr. Carte, Dr. Perceval Wright, and Professor Greene, may be reappointed, and that a further sum of £15 may be allocated for this purpose, Report on Observations of Luminous Meteors, 1858-59. By the Rev. BapveENn PoweEtu, M.4A.,F.R.S.,F.R.A.S., F.G.S., Savilian Professor of Geometry in the University of Oxford. In submitting the present continuation of my series of reports on luminous meteors I have little to say beyond what the results themselves indicate. I am indebted to the same friends as on former occasions for some valuable communications. Among these I may just refer to the observations of Mr. Lowe as including a notice of the periodical meteors of August the 10th of the present year, up to the amount of 70 per hour, and all diverging from a point in Perseus. In many parts of England the evening was cloudy. But at the observatory of Lord Wrottesley these meteors were well seen by Mr. F. Morton, who has communicated some interesting particulars respecting them, which are given in the sequel. The November meteors of 1858 were observed by the Abbé Leconte, at Hainault. It is to be regretted that no observations have been communicated of a nature to verify the theory of Sir J. Lubbock, and it is still more remark- able, that since the tirst announcement of Mr. Pettit of the distinct establish- ment of the existence of one, if not two, minute satellites to our earth, no further observations either of these or of any others, many of which may be presumed to exist, have been published. A valuable paper has appeared in the ‘ Philosophical Magazine,’ June 1859, ‘On the Periods and Colours of Luminous Meteors,’ by Dr. J. H. Gladstone, in which the author brings to- gether a number of important results and remarks, mainly founded on the observations of M. Poey, as well as upon the data furnished by the Cata- logues of the British Association. In the Appendix I subjoin a brief analysis of the leading contents of this valuable investigation. 1859. G 82 REPORT—1859. Observations of Luminous Meteors, Appearance and Brightness : Velocity de Bbnr: Magnitude: and Colour. Train or Sparks. or Duration. 1858. | h m s Oct. 24} 6 17 30 |=Arcturus.............|Colour of Arc-/No streak or separate|Fell slowly. Dura- turus. streams. tion 1 sec. Nove, Gi) A. csstescssnes]= Ronen = eee eon et loose sasaparsedessingthescss sone ssp apE a sahanecnasandlanierdyeamsevEsane Are Nov. 12].....+0- Seseees|naons ee ecenerereneee See Sitio eae Baas CBee sevcceevees se eeaeeeeneeeneane|seeeeereee sevesvececeses 1859. Feb, 23/11 20 31 [Increased in sizefrom|Very bright.|Slight streaks in its path,|Moved slowly, dura- =Ist mag.* to ith] Intense blue.) and burst into separate] tion 8 sec. size of ¢. Theseparate| fragments, which in- fragments stantly disappeared. The when it} star Urse Majoris burst yel-| was crossed by these low. fragments. Mar. 30] 9 15 =R size C veesicsseee At first red,|/Trail of light left in its}|Duration 50”....... then slowly| track. changing to pink, and finally _ to orange. Bright enough to see time from a watch. April” "Aly: ccbeeiacesss seecseater setescecbeaesaes[eetetecssssecseees|-etyehgsestpetgeacs stn: cnneracastl Keumemenncetees eee scneam April -22} 1 14 30 |=8rd mag.*............/Orangescarlet.|Leaving streaks in its path.|Rapid .....+.4.+-2++..- April 22] 2 27 a.m.|=4th mag.* increa-|Blue until it/Leaving streaks. Rapid. Suddenly sing to twice size of| entered the disappeared. 1st mag.* dark _seg- ment of an arch, when it instantly increased in size, and changed to an orange colour. Auge “U)eesescces. eeebe|ot EHOCER I eabiccatocsenlsuantrotatoccsdses|sesncunts paagebter® Gob dssedudstec|sedewbeusease tases voanm Aug. Diipesvetvesecats] ane Cece vecaerceeeseenenes [te eeseeeeeeessesesl® Oe ceseccececers PPPTTTTTTT Titi ee ee Aug. 9 OO ceeeseseeeee|seeeseeesetsoes deceeseceses|esecencesees eeeaeeleeresccccsesese eee beeesevencedoey|senecccesebeovecvecccens A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. 83 | by E. J. Lowe, Esq., F.R.A.S., &¢., 1858-59. Direction or Altitude. General remarks. Place. Observer. Reference. —_— — Perpendicularly down, passing|A well-marked me-|Observatory, E. J. Lowe, Esq.|/MS.communication 15’ N. of Arcturus. teor. Beeston. Mipecetiisencessiscses screeds certo pecs | MANY meteors, |[bid .......ssc000. (Ld. ssscseceeeeeeee(LDid. especially about 11p.m., all small, from 4th to 5th magnitude. Bessrscescvesevsevesestésscccesscsevess( Many meteors, allilbid ...... badenste UGE fodedocon sevs{[bid. small and having very rapid mo- tions. The 13th and 14th over- cast. From close to r Urse Majoris|This magnificent|Ibid.......... seveee[LGe sisceeseseeeeee/Mr. Lowe’s MS. to » Ursz Majoris, where it} meteor was pear- suddenly vanished. Place| shaped. Hada of disappearance A. 13h.| well-definededge. 4lm. Decl. 50° 1’ N. Increased in size, and disappeared at its maximum. There were streams of Au- rora Borealis im- mediately below the place where the meteor start- ed from. : rom above Ursa Major, to-|At its maximum|Highfield House,|W.Richards, Esq.|[bid. | wards the N. at an angle of} brightness when| near Notting- 60°, and passing midway be-| first seen. ham. tween the Great and Little Bears. Bienes cscdeectcccoscens Sophias isseceess Several meteors. |.......ce.scsececeecs E. J. Lowe, E&q.!1p; |From altitude 40° N.downwards|Deeper in colour/Observatory, Ti. vaaeaiae a a } at an angle of 40° towards| than a fine Au-| Beeston. it . W., and moving 10°, rora which was visible at the time. shies x2 From 80° above N.W. horizon|Aurora Borealis ...|Ibid ...... Ha 4); 30i ceeds |LBLA) fell perpendicularly down. RRR eT O EET EEA E HETERO Bete seweeeee Many meteors ween Tbid.. .c.ce..ceeeees Id. Obs Cece ase ewee Tbid. eiwasses Se catUBNENGs «cb 00esesceceseses|COVERCAMU! cacusdpeeess|vecesssteccdsuceees#e|LGs fesensansseudess| LOG. Reuarecencdeactacccsscd¥ssenseccnsesane|ONCLCASucncoe¥gecess|cceccusscsecbuesenccn[lQen cncacccsen see LDid. G2 84 REPORT—1859. Appearance and Brightness Magnitude. and Colour. Velocity or Duration. Date. Hour. Train or Sparks. 1859. | h m s Aug. 10)....csceeseeeee After 11 p.m. nearly cloudless. Very many meteors, especially between midnight and — hour, and, as only a fourth part of the heavens was watched, this multiplied by were of the second magnitude, but, as the moon did not set till half past 1, pro- her light. These meteors, with two or three solitary exceptions, could all be — between « and @ Persei. Several marked features were observed. Those me- moved more rapidly and over a larger space than those nearer to this point. | moved over a few minutes of space, and one meteor which I was fortunate enough | creased in size, and disappeared, without moving. Most of the meteors were gering streaks. The numbers increased up to 3 a.m.. j Aug. 12) 229 actn|= 2 .rcccccscsnsenes Mesnst DUC seencenenscs IAM seiseanaecuapons ves seseeeee| Rapid Streaks. 0.00. Aug. 11) 1 32 a.m.|Increasedfrom a point Bluish........+ There were brief streaks|Duration 0°5 sec... to that of a Ist shot out from it. mag.*, and again) decreased to a point. Aug. 11/10 &12 p.m.|.....cseeseeeees Pon eeseseee soveeeseseeens Ceeeleeevesececee CROC o eee re eee ret HH Eee SHEES HOSE HEHE EH EE EEREe eo Aug. 29) 2 50 a.m.|=1st mag.*...,,.......Orange........./Streak.,.,... dike vaicennen tee Rapids cvsarevseantns Aug. 291 3.15 10 |2nd mag.*.,.......+.+/Blood red......|Streaks widened ....,.++000-(RApid, see... ees Aug. 29) 3.15 20 [3rd mag.*,,....s.00+0e«|Colourless. ....|Streaks, sescessssssssseees se[Rapid...coscessssreeee Observations of Luminous Meteors Local mean ) 1858. | solar time. Mar. 23/11 44 46 |Much brighter than!........0000. Sol eeeeerecececeeee ed eeencesere Peeeelsesseeeseves Pobre teres Capella. May 5) 2 394 a.m.|Brighter than J. .eel...cccsscseeseeoes Disappeared instantlywith-|More than 5 secs., out diminution of bright-| perhaps 7 or 8 ; ness. secs. | Sept. 12;During the|A number of meteors'...... teesseseeeee/ome left trains....... ROPE Sancbascdsa Stone: aged night. chiefly in or near the Milky Way. pOctk, W754 pm ate ieee ee Oct. 5) 0 53 26 SOOO eee eee asec eee ceereeees cout ss seeserseennsl eens Cee eoeeeeeeeeMeesese eeeeeeeerleereees eee eeecaee eeeeeter ‘ Oct. 9) 6 33 23 Bright.cisssersabeescaite eengdneeavuchsrace see 1859. Seed eee e seers eeeePecrcccsseesecesiece errr reer ‘Jan. 2} 10 1lp.m.JA great number of......... Meteoes|sceneccsaces reac Fees ...|About 1 per minute. meteors. Mar, 18) 1 23}.a.m./Magnificent meteor. {Golden hwe....|Left a few SPATKS. seeseeees Disappearance not noted. April 6 During the|Great number in all'.........ccescceeslecees panera i cvkuetueasdacerccclaen ondsouiassGeieeeeaen night. parts, | SS. eye A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. 85 Direction or Altitude. General remarks. Place. Observer. Reference. 2 a.m.; the number seen was about 70 per Observatory, |E. J. Lowe, Esq,'Mr. Lowe’s MS, 4 would give 280 perhour. Most of them Beeston. bably the smaller ones were eclipsed by traced back to a point situated midway teors the furthest removed from this point Close to the point, the meteors only to detect on this very point, -appeared, in- yeHowish in colour, and had short lin- PEP ae eee eee reassess SH eeeeset Pee esas seeeesserans From midway between AlgOl|;ccccecensreaeesaes bevss|LDId ccs sescancssvenlLGnt evccavenseares bid, and Polaris, down towards N.W. horizon at an angle o 45°. A stationary meteor, at thelIt did not movellbid................ UGE scoctearpcerces c Ibid. point of convergence of allj amongst the the meteors situated half-way| stars. between a and B Persei. Above a dozen meteors seen}. gave the same point of diver- gence. The meteors much less numerous to-night, Fell across Aurora Borealis/Brilliant Aurora. |Observatory, Tel iedé: csseeea sss bids Screpearecnosn seooseee[Scarborough .../[d. ......+0+eeess.(Lbid. perpendicularly down from Beeston. slightly E. of Gemini. {Shot from the cupola of the/Aurora _ BorealisjIbid............. sae[LUe ieresenbevess sh « Ibid. | Aurora, which was situated! brilliant. near y Andromede, and moved towards y Arietis. Another shot from the same].......esseee Fossprcae|L DIG). codeemcies Area KA woes aeawses .»» Ibid. spot, moving to 8 Andro- mede. at Wrottesley Observatory. ; agit for 10° above the|Moon shining. Me-|Wrottesley Ob-|Mr. F. Morton. |MS.communication pole towards W. horizon. teor seenthrough servatory, opening of equa- esceane torial. {In E. moving slowly southward,).......+++++ gene vaderses Ibid, voavcyueveesse|L Car tess ertert sseeee(TDids altitude 15°, parallel to hori- zon through about 35°. NN ey fia peace ssdrsnsedos|eossncd esses siatcadl UN sect Sek NTT ow eee ta 10° below pole, parallel to h0-|.....scsssscosseseeeeeee(LDIG sesssseeseeesee (Le seseeesen eases Ibid. rizon. In 8. going W., at altitude 35°|Many smaller du- Bide cwzacstecscace Id. ..sesesseeeeee (Lbid. or 40°. ring the night in various Logit BiLtt P@gasus. co srecsscscssscscscsselnccecesecseevocses cocoslLDIGsseesscsveresere (Le sovesese reeves (Ibid. BPEPEraWacesshesscccsvoadoccssseassstalsucucsderdscuvuccesasaie|LDIC.ecrsss¢soccuess dS | ieatatees ec |LbIGs From S. to N. a few degrees|Seen through open-|Ibid ...... Soecereee Edlivissametvenss woes [[bid. below the moon. ing of dome. Moon full. POCO OT HREOC Oe He Here reese ee ee eHEEeOOnee ss seeetetessseseseeetes Ibid Cede eeberorees Id. Soe ceeretneeeos Ibid. 86 REPORT—1859. Appearance and Brightness : : Velocity or wie a Magnitude. and Colour. eo Duration. 1859. |h m s Aug. 10} ) ......s006 «-|Great display Of M€-|.....scceceeessseelssceeceseseeeeneeece daqedhrcivedtivedecsblareeatiumeease Aug. 1] teors. Aug. 21/10 13 p.m./Much brighter than]...........0...++ Followed by splendid train'5 or 6 secs. ......++ Capella. of sparks, visible some seconds after disappear- ance. Aug. 23] 1 13 a.m.|Brilliant flash through)............ sescceloancarsvsces seeeeeeees ancscensccclenevedas Geetiesawoeceese opening to dome. Observations of Luminous Meteors 1858. f : Dec. 2/45 _ p.m.|Large....... Wadetenexscee|ccavs ateaeensleteds Train for a few seconds. |Velocity moderate.. Daylight, Id. IGG | tilsaneesasacobepaoccn eceosce Bright, but not/(Train red, a mere impres-|Motion slow. ....... dazzling. sion on the eye.) Id. Id. Larger than * of Ist|/Bright blue. ../Train of sparks. First ascended and magnitude. then descended. DAD. |sccceteveentns rath vxcwnvonls seceasecdevisiectbecseccsscedsoeasbiansccecoussdeuelpvoneseeeh esseecoesseves Dec. 5)A few mi-l..........cccesscesees .«...|Very brilliant./After a few seconds train|.,.....sssssecerssveeess nutes af- white in place of first tersunset. appearance (wavy), verti- cal, then changed to horizontal, in 15 mi- - 1859. nutes disappeared. Mar. 23/A few mii |Large.s.....sscesssseeeee Brilliant....... olseeescebanee® eevncecicces sevgeeealecececes tee eeeeeeverees nutes past 8 p.m. Jan. 2} 830 p.m./=2 Jupiter............. Bright. ......00 Left a train for 1 OF 2,rcssssesvevcceseaseeees seconds. Half (@ Wil-|-.0e-cesecreiseusaqeseueki A smaller me-|.........-.-.. selcssveabercctcees|srdeudes™ scccvesdes tees nute later. teor. ‘June 21} 0 20 a.m.|=9Q.......06 Ragevecuass Orange......... Train of sparks: opake,|About 5 secs. ...... G. M. T. short. ‘Sept. 2/12 p-m:|=Ist mag.*.........06. Bluish — very|/Left a long thread of|/About | sec... ..... | pale. light behind. ‘Sept. 3/11 25 p.m.|=4th or Sth mag.*...}..cc.eeeeccceesscslevecccecceeecceseresesssses veeee-|Rapid, not ¥ sec. ... ‘June 26/11 52 p.m.|Diameter 15’, globu-|Bluish........ nollpcensdendoaensonrcr Rouge rscccusetlvaateey ceeeneases taceeee lar. 7 About Nearly globular. ...... Highly lumi-|No tail, no connexion. Descended gently... ll O pm. nous, _ but not very brilliant(?) About _the MOMENI Neve vasbauMbdaadee{cpaecsalreeb uss raslearatpccccsiast see araeesenecedioe Descended gently same time. - and steadily. A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. 87 I EEE EEE a ne : Direction or Altitude. General remarks. Place. Observer. Reference. | |S — sees. (ee Appendix. Wrottesley Ob-|Mr. F. Morton...|MS. communica- servatory, tion. Wolverhamp- ton. From S.E. at altitude 35°,|...coccccssecsreeesseeeeleseeeecees seosseeeee(Mr. W. P. Wake-|Ibid. through 40°, disappeared in lin. SS.W. In E.S.E.. se. csseseeeeeseseeeoeeees Moon bright. . — |esccssecceeenevenees Mr. F. Morton...|Ibid. from various Observers. From zenith towards E., disap-|....sescsesseeeeeeeeeoee Buckbury Hill,/Dr. C. Lingen.., Letter communi- peared at altitude 45°. Mordiford, He- cated by Mr. J. refordshire, 4 E. Smith, Here- mniles E. of He- ford Infirmary. reford. Towards N.E., disappeared at|Sun shining bright-/Brighton ......... Mr. T. B. Lane, jIbid. altitude 70°, moving obliquely} ly, a few light from N.W. through 8°. clouds. Disappeared at between 20° and|No report. Derby ....00rtess 30° altitude, towards S.E. from N.W. Disappeared at about 40° alti- tude towards S.W., commen- cing from 45°. Falling perpendicularly from|Barometer 29°30. Lat. N. 13° 20,|J.H.Hood, Mem-|Letter to Royal So- altitude 30° in W. Ther. 76°. Even-| Long. E. 50,) ber of Council,) ciety, communi- ing clear, many| on board ship Sydney. cated by Prof. falling stars. “ Emeu.” Stokes, Sec. R. S. Mr. F. T. Dubois.|[bid Clear sky. Belleau, Alford,|Mr. J. W. Giles. Ibid. Lincolnshire. Miss Powell. MS. communica- Vertically down from N.W. to|Lost behind houses. Tunbridge Wells, tion. E. of Cassiopeia. Grove-hill. From near Aldebaran to near]...««-...++ saprreelae ds Dunster, Somer-|W. Symons. Id. ¢ Eridani. set. Between Orion and ProcyOl].....seerssseeeeeeres Sebi sevencwesccsses TQS) Gavenc teehee st Id. nearly same direction. Moved in the arc Of a great]....sessssserereeenerees More Cottage,|W. J. Macquorn|Id. circle 40° or 50°, the middle Glasgow, 3] Rankine, Esq. miles S. of the ; passing through the zenith, from S.W. to N.E. Observatory. Dunoon, 25 m.|W. Crawford, Id. From S.W.to W. __saeneeeuesneneatevenenes west of Glas-| Esq. gow. From Polaris towards W. ——_[esscasseeeeeeeeeeereeees Glasgow ......++ Id. Id. Vertically downwards. First|Weather cloudy|London ......++ G. P. Greg, Esq.;|MS. communica- hisbrother,and| tion from Mr. and hazy, with lightning ;_ indi- stinctly seen. seen at 30° from zenith. J. Breen, Esq.| Greg. Td. ..sccces yeeeeee/EDid. plosion, much lightning in the same quarter. High up in the E., deseended/No thunder or|Bolton, South TG suanecas Aceves Ibid. vertically to horizon. lightning. Lancashire. Seen, but particu-|Halifax, York- lars not given. shire. REPORT—1859. 88 "Jot HOIMIOg “u010V G3) ‘H 7 "SIN, Aq uses) spoay "BaSyNos *20UIg *S1R4S pexy ou} ueyy *9SINOD S4I Jovan = yonu Ul yeyMouIos 409q 4 *.Sz JoAIasqo Jay30 |}Noge 0} ,cGe ynoqe jo pny -ue puezshta = |-19]8 ue wogy ‘AjAepnorpuadaied 4 3eur 0} paivedde 4y)3somye “gq Aq “G'S Wor} ]JaJ|"soas g yNOgE ‘MOTG|***"""***"** QUON| “az 4S— ueyy soyqsug)‘md 2 gQri6z Aine “6S8T *s1eqs Sut PPTTTLTLT TTT TTT Lr ree rr rrr errr rrr rer rere reer rere cd -j00Ys [es Aue yy atedsencseesdenls "pO “89300 Pai HeeoveereseereeseeoseloUT yIUOZ 943 gnoqe worse’ prdeyl ures Areyuowopy) re st uLyY soIySig] “ud cg g lgz'3dag *payeorp “Ul 9194} BOULYSIp 94} OJ pus ‘ ° —— > ‘civiZerp ul UMOYs se ‘role BSI() 19A0 AT[eIUOZLAOY passed 4]|"** puodas [ Jnoqy/ Ulery AIezUOUIO|] —*93TTT AA 4 3vUl 4ST =] ‘urd 9% OTIgt3deg um Uy] ‘8S8T *SsyIBUYy BIC oH ERC § uoryeMC “WRAY, *INo[OD ‘azis yuoreddy “mow | ‘ayeq oy “Sy | ‘euojspryyy “FT *¢ “Aq: Aq sioajayT JO suoijeasasq¢, 89 A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. TI TI LILI tity titty ti ri ayaiaijajelajaye; ec) ;e | rir rj) g),s)s seeeeeesseneeeermaoT vere SHaMBy, epamoipuy seeteere snag) SOpvlotd * IOUT BSI.) . I see | wee | eee | vee | eee | oe eee | eee | wee oe | wee | wee | wee lowe I wee | woe | coe | woe | wee | wee . see leweereee eeeeees 893004 + | wee | oe see | vee | coe | woe | eee | wee I we | eee | wee | eve | eee [eee | woe | eee | eee | woe | woe | vee I + | woe | woe leweeeneeee **snyontqdg see | wee | eee we | eee | coe | eee | eee | coe | oe wos | wee | coe | eee | oes looe | woe | eee | eee | woe | wee | wee | wee ¢ wae | wee [coer teenneererenesseeeseees snasiog eee | cee | coe | coe | woe | woe | eee | wee | woe | woe | vee se | eee | wee | woe loos | coe | ee I wee I eee | oes | woe | vee seer sens eseeee sijvol0g eUuo010y PPTTTEOTTE Tree TT so[no1loyL PUTTTT ITT Tr snuiyqdjaq se eeeeeeeeeettteeerereetens znby cee lee tocesscccccceoocvsoess Bic OISSU) seveeeeeeeaeseeeenseeeereveees BIATT ae |esceevececsresceeresseee TUTOa+) eee eenreeseaeteseeseerers esuny se eeeeeeetetoseresees Jofepy espn, ; seeeeeesren se OORT “pepo, | co v2 a9 4 69 00 69 0960.69 60 ON EU mA tt tH be : ei "BIQuT 0a'T *snuroonded “10}d[nNIg “snsesog *snurydpeq *snasiag *epaulolpuy *suodiag “r0leyy BsIQ) *soNO1O FT “snyontyda *SNIE}ZLG “epmby *saj00g OJ, mol “rofepy stued *sITBASNy SlOstg *seotualag eMog *sl[valog BuoI0”D pe es i nF eee ee ee eee nea eee eee ee ee eee ee SS "SWAN “bey ‘sucky +f +5 Jo 3srT ay} Ul paparodvad sv ‘SUOTEI[aISUOD aaIQDadsa1 JY} UB2MZaq Ssed 0} PaAsasqo SIDd}2TW JO JaquINN, ay} Supmoys ATAV], 90 REPORT—1859, Observations of Luminous Meteors, by G. J. Symons, Esq., M.B.M.S., at 27 Queen’s-road, Camden Town, London. Date. 1858. Sept. 5 6 12 Oct. 31 10 28 1859. Jan. 22 April 6 6 21 May 12 July 4 Aug. 2 Time. hm s 9 21 p.m. 9 53 p.m. 9 59 p.m. 10 9 p.m. 10 28 p.m. 7 22 p.m. 7 25 p.m. 7 25 30 p.m. to os) wo ei) Po B o wo _ wmomowmw 9.00 CO Csr OOO OOO owowoon oo orm Orme OO oe Nowe eB SO HOR DOT OmM OOOH Woo wnmodc§ wo oO ~ Mag. Colour. | Train. white none blue broad white none white slight white none white none Direction. From 3 Urs Majoris towards 8 Urs Ma- joris. (Bright, very slow.) From Polaris towards Corona Borealis. From a Ophiuchi towards the horizon. From 5° N. of Vega towards « Ophiuchi. From @ Cygni towards ¢ Aquilz. From Corona Borealis towards 1 Urse Ma- joris. =21 |red & blue| 30° long |From 3 Urse Majoris towards Arcturus. 2 VV 3 1 3 2 2 2 4 2 3 1 2 1 2 2 2 1 3 1 1 red slight white none white none white none white none white none white none white none white long white none white none white none white none white none white none white none white none white none white none white none white | 40° long white none white none white none white none white slight white | slight See Note|See Note (1). (1). yellow none yellow | slight white none white none white none white none white none white none white none white none white none white none From 7 Coron Borealis towards ¢ Bootis. From £ Cygni towards 6 Ophiuchi. From 4 Urse Majoris towards Coma Bere- nices. From ¢ Persei towards 3 Aurigz. From « Persei towards 3 Aurigz. From Capella towards Jupiter. From Pleiades towards Aquila. est course I ever observed.) From y Pegasi towards Fomalhaut. From Capella towards « Ceti. From Algol towards Capella. From ¢ Ceti towards a Sculptoris. From x Cygni towards a Draconis. (Slow.) From & Cygni towards @ Delphini. From 3 Draconis towards « Lyre. (Swift.) From y Lyre towards Ophiuchi. From y Draconis towards ¢ Herculis. From y Cygni towards Albireo. From y Cassiopeiz to « Andromede. From £ Draconis towards s Herculis. From A Andromede towards y Cygni. From # Aurige towards # Pegasi. (The long- From » Geminorum towards y Orionis. From y Tauri towards « Ceti. From « Leonis towards Z Leonis. From « Geminorum towards « Persei. From « Geminorum towards a Orionis. From 5° below 2 Geminorum towards Jupi- ter. (Well seen, though bright moon- light.) From 2 Urs Majoris towards Corona Bo- realis. From a Herculis towards ¢ Bootis. slow.) From e Herculis towards u Sagitt. (Slow.) From ~ Lyre towards y Serpentis. (Very swift, seemed close.) From « Delphini towards @ Lyre. (Rapid.) From « Herculis towards « Ophiuchi. From ¢ Cygni towards y Aquile. From Altair towards Arcturus. (Slow.) (Very From 4 Draconis towards y Serpentis. (Swift.) From z Bootis towards 6 Libre. (Slow.) From y Bootis towards Coma Berenices. From g Corone Borealis towards « Herculis. From « Draconis towards y Herculis. A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. 91 Date. Time. Mag. | Colour. | Train. / Direction. 1859. |h m s Aug. 4./11 44 p.m. >1 white none /|From ¢ Urs Majoris towards Arcturus. 11 52 p.m. 2 white none From y Cygni towards 3 Aquilz, 11 52 p.m. 4 white none |From y Cygni towards 3 Aquile. 11 53 p.m. 1 white none From a Delphini towards + Sagittarii. (Swift.) 11 57 p.m. 1 white none /From @ Aquile towards Corona Borealis. 5| 03630am.} 3x1 ic on (From 6 Ophiuchi towards « Sagittarii. 2). 11/10 40 40 pm.| 2x1 white slight From p Cassiopeiz towards 6 Persei.* 10 52 p.m. 2x1 | yellow | sparks |From « Cassiopeize towards 6 Andromede.* 111632pm.| 2 white | none (From 3 Aurige towards Castor.* 29,1 5am. | 2 white none |From & Aquilz towards « Sagittarii. I3lam. | 2 white none (From Delphinus towards y Capricerni. (1.) This meteor was of very considerable apparent diameter, of a pale yellow colour; on exploding, the sparks assumed a bright crimson hue; it was remarkable for its very slow motion. (2.) This meteor, when first observed, was little more than 2nd magnitude, but rapidly increasing in apparent diameter: it presented at its disappearance a well-defined disk. Its colour was a brilliant emerald green and the body of light such as to illuminate with the same tinge 30° or 40° of the adjacent sky. There were no sparks, and it was very similar to one or two I have seen before, and which I cannot better describe than as resembling a body of light enclosed in a filmy envelope. APPENDIX. No. 1.—Letter from Mr. Hood to the Royal Society, communicated by Professor Stokes, Sec. R.S. Pt. de Galle, Ceylon, January 15, 1859. Srr,—I beg to send you the accompanying description of a phenomenon observed on board the Steam-ship Amew: as a similar one had never been noticed by any of the ship’s officers or passengers, amongst whom were two captains of Her Majesty’s Navy, it seems worthy of record.—I remain, Sir, your obedient servant, J. H. Hoop, Member of Council, Sydney, N.S.W. On the 5th December 1859, lat. N. 13° 20’, Long. E. 50°, a very bril- liant meteor was observed, a few minutes after sunset, in the west, falling perpendicularly from an apparent altitude of 30°. In a few seconds there appeared, in the place where the meteor was first visible, a bright white cloud, in shape S= , perpendicular to the horizon, and crossing the light transparent ruddy stratus-clouds ; gradually it ascended slightly, and becaine horizontal, remaining nearly unchanged (but slowly moving on with the light breeze) for about fifteen minutes, when it gradually disappeared in the haze of the evening. Its appearance was very remarkable, in shape thus “YW 55_ and of a bright clear white colour, against the golden-coloured evening sky. The evening was very calm and remarkably cool, falling stars unusually numerous. Bar. 29°30. Ther. 76°. No. 2,—Analysis of a paper by Dr. J. H. Gladstone, Ph.D., F.R.S., in the * Observed at Thornton Vicarage, near Leicester. 92 REPORT—1859. ‘Philosophical Magazine,’ June 1859, entitled “ On the Periods and Colours of Luminous Meteors,” With reference to the explanations of the periodical star-showers, so often attempted, the author examines the speculations of M. Charles, and, from comparison with other ancient records besides those cited by that writer, comes to the conclusion that his ingenious hypothesis—viz. that there may be a secular progression of these periods, and that the showers of February, March, and April, in the middle ages may be the same as those which now recur in August—is untenable. ‘It rather appears that the periods remain stationary, sometimes for centuries, but the transit of these streams of meteors through our atmosphere is liable to interruptions and changes which we may speculate upon, but cannot yet determine.’—p. 2. With respect to the varied colours of meteors, on examining the numerous results collected by M. Poey, the author suggests whether we always correctly translate the names of colours used in records of such remote antiquity as those of the Chinese and others referred tc. He also controverts the theory of M. Doppler (referred to in the last Report), and in general is disposed to hold that nearly all meteors may be arranged under two grand classes,—blue, and orange inclining more or less to red, while in passing from the zenith to the horizon changes of colour are constantly noticed. The trains are some- times of different colour from the body, and the radiation of colour over objects is also often different from the colour of the meteor. The author very justly remarks that observers often call the same colour by different names. But apart from this source of fallacy he conceives a real difference possible, and ‘that a meteor may emit rays which in the aggregate would produce one colour, and yet may affect the observer with a sensation of a different colour. This may arise from absorption, intensity, or contrast.” —p. 7. He then supports this view by several arguments and instances; in parti- cular he conceives the absorption of the atmosphere, especially when satu- rated with vapour, may account for the change of colour in the passage of meteors, which generally terminate in red, known to be the ray most trans- missible through mist. It has been observed by Helmholtz and others, that light of any colour, if of high zntensity, tends to give a sensation of whiteness. This the author thinks will account for the radiance different from the colour of the meteor; as well as for an apparent change of colour, with a change of intensity from passing through a dense atmosphere. All appearances of colour are greatly affected by contrast; hence he thinks the difference between the colour of the bodies and trains or other products of meteors may be explained in many instances. The author examines the question whether there may be any relation be- tween period and colour in meteors. Those occurring at one period may be of a different composition, and consequent colour in combustion, from those at another. Such a relation is supported by many of the comparisons of records made by M. Poey. The author also gives a tabular view, from which it results that “ August is marked by a great deficiency of orange, and a great excess of blue meteors—while November exhibits comparatively few blue, and a very large proportion of orange meteors, with a slight increase of the red.”—p. 9. He finally observes that all meteors, whose composition is known, consist of many ingredients which may possibly all be ignited together, or separately, in different instances, thus giving out different rays for each component, and these again different for different intensities of combustion. In support of this view he refers to the known components, iron, sulphur, and phosphorus, A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. 93 as well as cobalt, zinc, nickel, &c., and the intense but greatly varied illumi- nations they give when in combustion, especially under the influence of gal- vanism, which resemble the light of meteors. No. 3.—Miscellaneous Notes on Meteoric Phenomena and Theories. In the Transactions of the American Philosophical Society of Philadel- phia, vol. viii. New Series, Part I. 1841, the student of meteoric phenomena will find two valuable papers treating the subject, as connected with cosmical forces, and regarding meteors as planetary bodies revolving in our system about the sun, but under certain conditions perturbed by, and at- tracted to, the earth; both papers contain elaborate researches, of which it would be impossible here to attempt an analysis, investigating as problems of physical astronomy the nature and modifications of their orbital motions. They are entitled, Art. VIII. ‘On the Perturbations of Meteors approaching the Earth,” by B. Pierce, M.A.; Art. IX. “Researches concerning the periodical Meteors of August and November,” by Sears C. Walker, A.P.S. In the ‘ Philosophical Transactions,’ 1840, Pt. I. Sir F. Palgrave gives an account of some ancient records of meteors. An ancient chronicle, April 3, 1095, speaks of “ stars driven like dust.” July 26, 1243, Matthew of Paris describes falling stars seen 30 or 40 in one minute, so that “ if they had been true stars, not one would have remained in the sky.” E. W. Brayley, Esq., ‘ Philosophical Magazine,’ vol. Ixiii. p. 385, 1824, and vol. lxiv. 1st Series; also vol. xix. 3rd Series, p. 500; and Annals of Philos. January 1824, p.’73, gives a variety of details respecting meteors and aerolites. In the last-mentioned paper he notices the fact that tle meteorites which have been examined as to their density and composition form a con- tinuous series of varying characters from the most compact iron to the most crystalline or scoriaceous stone. The hypothesis of nebulous matter existing in masses analogous to comets, and like them revolving in our system, as the origin of meteors, has been sup- ported on the strength of general analogy, and the probable extensive diffusion of this kind of matter as evinced in the continual discovery of new telescopic, as well as large, comets; so that we may well admit with Kepler that their number may be infinite, and the universe full of them. Such masses might be expected to undergo great retardation from a resisting medium, and ulti- mately to be condensed into the sun, or any solid planet to which they may be attracted; the retardation gradually contracting their orbits till they fall on the central body. It has been also alleged that in some instances the nebulous tails of comets, such as those of 1811 and 1823, may have mixed with our atmosphere, and perhaps from electric action have given rise to luminous phenomena having the appearance of shooting stars. Several writers have speculated on the connexion of meteors with electric phenomena, or even their electric origin. A hypothesis of this kind, supposing diffused atmospheric matter to be carried by electric currents, has been advocated by Professor Maas in the Bulletins of Royal Acad. of Brussels, 1847, p. 303. On this subject the reader should refer to ‘Cosmos,’ 1st Translation, p. 123 ; and to sonie remarks of Poisson, zbid. note p. 402. Also to the masterly paper of the late Mr. Galloway, F.R.S., F.R.A.S., in the ‘ Notices of the Royal Astronomical Society,’ vol. v. Among the cases recorded in the different catalogues, there are great num- bers mentioned as attended by coruscations, flashes, and trains of various kinds, which can hardly be conceived otherwise than of an electrical nature. The serpentine or zigzag courses of many meteors recorded are incompatible with a solid body revolving in an orbit. It has been noticed by Professor C. P. Smyth that the zodiacal light is 94 REPORT—1859. slightly excentric with regard to the sun, so that the earth passes through its extremity once in its revolution, about Nov. 12.—[ Edinb. Trans. ] Chladni conceives innumerable small bodies revolving in the solar system, and subject to the laws of gravitation. Messier, in 1777 (Memoirs of Royal Acad. Paris, 1777, p. 464), has recorded ‘ Observation singulier d’une pro- digieuse quantité de petites globules qui ont passé au devant du disque du soleil.” Mr. Rumker has more recently recalled the attention of astrono- mers to the subject. Some supposed analogous phenomena are not perhaps really entitled to be so considered; yet they tend to support the fact that diffuse matter of kinds little known may exist. Such instances are those of dry fogs occasionally observed. The most re- markable on record is, perhaps, that of 1783; a remarkable year, in which, besides this phenomenon, there occurred a great volcanic eruption of Hecla, earthquakes in Calabria, and the passage of one of the largest and most re- markable meteors ever witnessed, and seen all over England. The fog occurred over a great part of Europe, the north of Africa, and North America; but not in the middle of the Atlantic, perhaps owing to some current of the atmosphere which partially cleared it away. It continued more than a month. In some places it was observed to obscure or redden the sun; yet in general the stars were seen through it. It was accompanied by an unpleasant smell, was perfectly free from moisture, not affecting the hygrometer, and exhibited a phosphorescence. It has been argued that its long continuance precludes the idea of its being the tail of a comet; but this is no proof that it might not have been a portion detached from such a nebulous mass, and retained by the earth till condensed or dissipated: whether it could be connected with the volcanic eruption, or with the meteor, remain questions open to speculation. In 1831 a similar phenomenon was observed on the African coast, N. Ame- rica, and Asia Minor, as well as in France and some other parts of Europe. The sun is said to have appeared blue through it; but the stars were occa- sionally obscured. These phenomena, however, may be purely terrestrial ; as the Harmattan, or blowing of dust from the African deserts over the Atlantic, as well as the dust from voleanic eruptions, have been known to produce very similar effects. In the catalogue originally given by Chladni (see Edinb. Phil. Journal, No. II.), largely confirmed by later instances, we find full verification of the fact, that meteoric matter has fallen of every degree of density, from the con- dition of almost pure metal to that of ore or oxide, more or less earthy, to matter of light, porous, soft or spongy nature, or even of the character of fine dust, or a dry fog or haze floating in the atmosphere: though it must be owned, the connexion of such phenomena as the last mentioned with those of meteoric masses may not be sufficiently proved. [For some details in reference to this point, see Arago on the comet of 1833 (translation by Col. Gold); also ‘Comptes Rendus,’ 1847. ] The student should not overlook the ingenious conclusion of Sir H. Davy (Phil. Trans. 1817, Pt. I. p. 75), that the combustion of meteors must be that of solid matter, since combustion of elastic fluids could not be supported in so rarefied an atmosphere as exists at the great heights at which it oceurs even in those instances which fall within the limits of our atmosphere. : One of the most instructive cases is that of a great meteor observed at the Cape of Good Hope (Phil. Trans. 1839, Part 1.) which was seen to burn by daylight and to fall in portions, which were immediately collected and examined. The most considerable part of it is preserved in this country. REPORT ON A SERIES OF NEPALESE SKULLS. 95 Those masses appear partially rounded, but broken in their fall, and of an earthy texture like baked clay, easily broken. The meteorite which fell at Launton, 1840, preserved in the collection of Dr. Lee, at Hartwell House, is of a somewhat angular form, but having all its edges and corners rounded : an exact model of it exists in the Ashmolean Museum, Oxford. No. 4.—Extract from the communication of Mr. F. Morton.—The August meteors at Wrottesley, 1859 :— “The display of meteors during the night was very grand. During an hour, from 15 10™ a.m. to 2" 10™ a.m., 72 were counted in all parts of the heavens, the majority of which were followed by trains of sparks. The pre- vailing direction of their flight was towards the N.W. During the next half- hour at least 40 were seen, but the number was not accurately noted. A great number of those observed (from 25 to 30) were very fine, larger in fact than Capella or a Lyre, which were then visible, several being larger than Venus when brightest. Though two observers were on the look-out together, no meteor was counted twice. “ Aug. 23, at 1" 13™ a.m., the opening in the equatorial dome being E.S.E., a brilliant light was seen reflected from the western wall. This must have been caused by a very fine meteor, as the room was strongly illuminated at the time by the moon. Local mean solar time has been used throughout.” Report on a Series of Skulls of various Tribes of Mankind inhabiting Nepal, collected, and presented to the British Museum, by Bryan H. Honason, Esy., late Resident in Nepal, &c. &c. By Professor Owen, F.R.S., Superintendent of the Natural History Departments in the British Museum. Mr. B. H. Hopeson, who has contributed an important element to the an- cient history of India by his successful labours in unrolling the Buddhist re- cords and deciphering the Buddhist inscriptions of Nepal*, has established an additional claim to the gratitude of the ethnologist by the assiduity with which he has collected the skulls of the various tribes or races of that part of the Indian continent. This collection forms part of a still more extensive series of objects of Ne- palese Natural History, contributed by the liberality of Mr. Hodgson to the National Collections. The human crania, most of them adult, are upwards of 90 in number, and belong to the following TRIBES. No. of Skulls. No. of Skulls. No. of Skulls. PEW AR tie acbdes LE|LRAGN .650--e0¢¢, 3| NEPAL (proper)... 1 BBO A co sana eo cs SV SHOPA <'s5..0:dgaacs 2)|Bencat (Fakir) ..- 1 0 ol a DIORA ois 2) si mi 1|}Gances (man of the MORME ....{ «+ Pat pe LEM ATG 2, cide ha ¢,0:8:512 TL. plaiaey deat 1 TAGAR oo ios sini) DODO. «a0. eeeeee 1|LoOwLanps (caste un- Sunwak.... PAA ROGCH. ns a diewiad 2), SROWRDIES su tninn 10 EaMEU ..ds26 «ee. 5|Kuampa A he == REPRAN TL «ciao cal coins ER GNAEE 5.040 gies 2 90 SORUNG. 5.04 20 nb 4|HILL-MEN........ 2 * Journal of the Asiatic Society of Bengal, in the volume on General Subjects of Hima- layan Ethnology. 96 REPORT—1859. NewAr Tr1BeE (12 skulls). The general characters of the skulls of this tribe conform to those of the Indo-European type; but they are all slightly prognathous. They present a regularly-shaped fullish-oval cranium, showing varieties between the two extremes, as to length, of from 7 inches 6 lines (19°0) to 6 inches 4 lines (16:0)*, and, as to breadth, from 5 inches 8 lines (148°0) to 4 inches 11 lines (126°0); the broadest cranium being the shortest, viz. 16°0, the nar- rowest being the longest, viz. 190. The forehead is narrow, and, in most, low ; but with well-marked varieties in this respect. The cheek-bones are rather prominent in a few skulls. ‘The nasal bones show much variety, from great length and prominence to AZthiopian flatness. The supraciliary promi- nence is generally but little marked. ‘The mentum is rather prominent, but short, except in two skulls, marked “ from Saukhmol, Hill-man and woman.” The frontal suture is obliterated, and the alisphenoids join the parietals, in all these crania. The complexity of the sutural lines is various, being in most rather simple. The broad cranium (1 2, x, x, x) belongs to the so-called ‘ brachycephalic’ type; the narrow one (1 v, v, v, v) to the ‘ dolichocephalic’ type. The average, which is also the common breadth, of the cranium, is 5 inches 3 lines (1340). Characters, Varieties, or Anomalies of DentitionIn the Hill-man, the molar, m 1, has the enamel worn from the summit, and a smooth hollow of dentine is shown: p 4 and m 2 are partially worn, and p 3 and m 8 are slightly worn. In two skulls, the last molar, m 3, is not developed on either side of the mandible. Lercua TRIBE (9 skulls). The majority of these skulls show a greater prominence of the malar bones than in the Newar tribe; but whilst one Lepcha (6. e, e, e, e) exhibits a beautiful Indo-European form, another (1 a, a, a, a) closely resembles or repeats the Australo-Papuan type of cranium. ‘The differences, as to length of cranium, range from 7 inches 4 lines (186°0) to 6 inches 4 lines (162°0) ; in breadth, from 5 inches 8 lines (144°0) to’5 inches (128°0) ; the narrowest skull (1 a, a, a, a) here, also, being the longest. We have in this series of skulls both brachycephalic and dolichocephalic types strongly marked—most of them having crania rather of the shorter than the longer oval, when viewed from above. All are more or less prognathous; those being least so which have least prominent malar bones. The chin is prominent in all. The nasal bones show the same range of variety as in the Newar tribe, ranging from prominence with compression and length, to breadth with shortness and flatness. There is more variety in the prominence of the frontal sinuses and superorbital ridges in the Lepcha than in the Newar tribe. The frontal suture is obliterated, and the alisphenoids join the parietals, in all,—in one skull (1 ¢, ¢, ¢, ¢) by a mere point, in the rest broadly, as usual in Indo-European skulls. The forehead is rather low; is narrow in some: in one only is it broad in proportion to the cranium. Anomalies of Dentition.—In one skull (1 y, y, y) m 3 is wanting in both jaws, in which m 1 and m 2 are worn, and there is no trace of loss of m 3. In another (1 d, d, d, d), the left p 4, upper jaw, is abnormally small. Upon the whole, these Lepcha skulls are to be referred to a low, unedu- - cated, and undersized family of the Indo-European race; but one (1 2, z, z) approaches the AZthiopian type, another (1 a, a, a, a) the Australian type ; * French decimal system. ON A SERIES OF NEPALESE SKULLS. 97 whilst a third (0. e, e, e, e) shows almost the Greek model, save in a slight prognathism. Buotia Trise (9 skulls). In the nine skulls of this tribe it is instructive to find, asin the two former tribes, both the brachy- and dolicho-cephalic proportions exhibited. The extremes of length range from 7 inches (177°0) to 6 inches 3 lines (160-0) ; those of breadth from 5 inches 8 lines (144°0) to 5 iaches 1 line (130°0) ; the broadest skull here, also, being the shortest. Save in two instances, ap- parently females, the malars are large and prominent, and the general aspect of the skulls is rather that of a Mongolian than Indo-European type. The former is very strongly manifested in a skull (1 9g, g, g) marked “ Inu Bhotia trans nivem” ; and also in a “ Sharpa Bhotia” (1 z, 2, z, z), which shows the shortness and breadth of cranium, which has been ascribed by Blumenbach to the ‘Turkoman’s,’ skull. In the Inu Bhotia the frontal suture is persistent, and the interorbital space is very broad: the muscular insertions on the occiput are strongly marked. All the Bhotias are prognathous ;.and, in all, the chin is prominent. ‘The nasal bones are the seat of the same kind and range of variety as in the preceding tribes. In all the skulls the alisphenoids join the parietals, but with variable proportions—from two-thirds of an inch to a mere point. Dental anomalies.—m 3, on the left side of the mandible, has protruded by the side, instead of the summit, of its crown. Murmti Trise (7 skulls). This series includes two certified female skulls and one skull of a child. One of the male skulls is more prognathous than in the previous races; in this respect the maxillary characters are those of the Ethiopian; but they are combined with a vertical forehead, with well-developed nasals, and with moderate malar bones : the cranium shows the Caucasian oval form: the ali- sphenoid joins the parietal by a suture of one inch in extent. The other male skulls are less prognathous and in various degrees: two of them show prominent malars: the nasals vary from extreme prominence (J. #, 2, 2, 7) to flatness (2. m, m,m,m). The forehead is low in most, and is narrow in all. There is as much variety in the proportions of cranial length to breadth, in regard to the number of skulls, as in the foregoing series. The longest skull is 7 inches 3 lines (182°0); the shortest measures 6 inches 3 lines (158°0): the broadest is 5 inches 5 lines (137-0); the narrowest is 4 inches 10 lines (123-0): the shortness being more or less compensated by breadth, and vice versd. In all the seven skulls the alisphenoids join the parietals, and the frontal suture is obliterated. These skulls show much variety in regard to the complexity of the cranial sutures. Maaar Trise (5 skulls). Of this tribe, three skulls are of males, and show a longer form of cranium, with larger and more robust general proportions, than in the Murmi tribe. The length, in the three males, ranges from 6 inches 8 lines (166:0) to 7 inches 5 lines (188°0) ; the breadth from 5 inches (122°0) (in two) to 5 inches 35 lines (135°0). In two skulls the malars are prominent: in all the upper jaw is prognathous, and the lower jaw has a prominent mentum. The nasal bones are generally prominent. The occipital half of the cranium is unsymmetrical in one skull (/. 2, «, u, w, «), which also shows a large foramen jugulare on the more prominent side. The alisphenoids join the parietals, and the frontal bone is single, in all the seven Magar skulls. 1859. H 33) > - REBORT—1859, > 4a Sunwar Trize (6 skulls). Four out of the six skulls of this tribe show the broad and short or rounded form of cranium ; a fifth would be classed as dolichocephalic; the sixth shows an intermediate type. The upper jaw is short, broad, slightly prognathous ; the mentum moderately prominent; the malars prominent in all: upon the whole, the Mongolian or Turkoman type prevails in this series of Sunwar skulls. The dolichognathous skull (/. 0, 0, 0, 0, 0) measures, in length, 7 inches 4 lines (186°0); in breadth, 5 inches 13 line (131-0): the average length of the four brachycephalic skulls is 6 inches 5 lines (167:0); the average breadth is 5 inches 9 lines (1450). In all the skulls the alisphenoids broadly join the parietals, and the frontal suture is obliterated ; the nasals vary from pro- minence to flatness. Limeu Trize (5 skulls). These skulls exhibit a great range of variety: the one marked “/.z,x, 2,2, 2,” in the oval contour of the cranium and face, in the delicate, almost vertical malars, in the form of the maxillaries, and in the development of the nasals, conforms to the Caucasian type ; but although the forehead has proportion- ally a good shape and development, the capacity of the cranium is small. The skull marked “1 v, v, v, v, v,” in the narrow and elongate form of the cranium, in the flatness of the nasals, in the projection of the broad jaws, and divergence of the malars, exemplifies the Negro type of skull. The length of this cranium is 7 inches 3 lines (185°0); its breadth is 5 inches 42 lines (1360). The skull marked “1 2z, z, z, z, z,” combining. a broad rounded form of cranium with a broad malar region, anda broad, short, yet somewhat prognathous upper jaw, conforms to the Mongolian type. The same type, with a somewhat longer form of skull, predominates in No. 1 w, w, w, w, w, in which the length of the cranium is 6 inches 5 lines (168°0), and the breadth is 5 inches 8} lines(145°0). In all these skulls the alisphenoids join the parietals, and the frontal is undivided. The same range of variation in the development of the nasal bones prevails ‘as in the preceding series. The principal anomalies shown in this series are the anchylosis of the atlas to the occiput inl y, y, y, y, y, leaving only the left neurapophysis, behind the condyle, free; this is separated from the right neurapophysis by an in- terval of 7 lines: the right posterior zygapophysis is double the size of the left one, and is convex: the nasal spine of the premaxillaries is much produced. In the skull marked “ | w, w, w, w, w,” the upper or interparietal part of the ‘squama occipitalis’ is formed by three large ‘ wormian bones.’ KrrantI Tribe (5 skulls). The same exemplification of both Caucasian and Mongolian types is given by this as by the preceding series of five skulls; but no Kiranti skull shows the simious combined with other Ethiopian characters: the nasal bones in all are prominent and well-developed. The oval or elongate form of cranium prevails, with a moderately prognathous jaw. In three of the skulls the malar bones project outwards. ‘The chin is well-marked. The length of the cra- nium varies little, the average being 6 inches 10 lines (174°0) ; the breadth varies from 4 inches 9 lines (120°0) to 5 inches 5 lines (138°0). In all the skulls the alisphenoids join the parietals, and the frontal is undivided. . Anomalies.—One skull (1 a, a, a, a, a, @) shows a wormian bone in the sagittal suture, and a pair of well-marked ‘ paroccipital’ processes: the skull (1 4, 6, 6, b, b, 6) shows a mal-position of m 3 on both sides of the upper jaw. ON A SERIES OF NEPALESE SKULLS, 99° Gurune TRIBE (4 skulls). The Gurung tribe is exemplified by one skull of an adult male, and by three skulls of boys, in which the dentition has not gone beyond the acqui- sition of the first true molar, with the deciduous series. These skulls show a'slight family likeness in the degree of flatness of the nasal bones, with a slight general prominence of the interorbital region, and a moderate pro-. gnathism. In the adult male the forehead passes without indent into the nose, as in the Grecian type. The frontal suture is persistent; but it has been obliterated in the younger skulls. In the skull of the youth (19, 9,9,9,9,9), on the right side, the frontal joins the squamosal ; on the left side a wormian intervenes between the alisphenoid and parietal: in the others the usual june- tion of these bones obtains. The chin is prominent in all. The length of the adult skull is 7 inches (178*0); its breadth is 5 inches 8 lines (145-0). In this skull the squamosals are abruptly prominent below the parietals, and a great part of the suture between the ex- and super-occipitals remains, The following are the dimensions of three of these skulls :— ¥ | Youth. Child. Gurung : males. Adult. Deciduous & m1. Deciduous. in. lines. mil. n. lines. mil. in. lines. mil. Length of cranium ... 7 0 (178-0) 6 5 (163-0) 5 7 (144:0) Breadth of cranium...| 5 8 (14570) 5 63 (140°0) 5 14 (130°0) Anomalies.—In the boy’s skull (1 A, h, h, h, h, h), with m 1 and the de- ciduous set of teeth, the right condyloid cup of the atlas has coalesced with the occipital condyle, and the rest of the atlas is so closely applied to the margin of the great foramen, as to indicate an ultimate, if not speedy coales- cence of that part of the vertebra with the occipital one, UrAOoN TRIBE (2 skulls). The skulls of this tribe are of adult males; they show a rather narrow. elongate form of cranium, with prognathous maxillaries. In one the cheek- bones project, in the other not. In both the nasals project and are short, with the usual indent between their root and the forehead. In the slightly larger skull the length of the cranium is 7 inches 14 line (182°0); the breadth of ditto is 5 inches 4 line (1300). The alisphenoids meet the parietals, and the frontal suture is obliterated, in both skulls. Sopa or Soxpa TRIBE (2 skulls). The cranium in one of these skulls is short and broad, in the other it is long and narrow; the malars are somewhat prominent and the jaws slightly prognathous in both. In the dolichocephalic variety the length of the cranium is 7 inches 5 lines (188°0); its breadth is 5 inches 6 lines (140°0). The alisphenoids join the parietals, and the frontal suture is obliterated in both skulls. Dima TRIBE. The ‘ Dimal’ skull most resembles those of the Gurung tribe, especially in the form of the interorbital part. This skull is chiefly remarkable as exem- plifying the rare disease of hypertrophous thickening of the parietal bones. Bovo TRIBE. This shows the dolichocephalic or elongate cranial form, with prognathous jaws and almost vertical, not projecting, malar bones. The nasals are slightly prominent, with a little depression between them and the forehead. H 2 100 REPORT—1859. The length of this cranium is 7 inches 2 lines (184°0) ; its breadth is 5 inches 3 lines (135:0). The alisphenoids join the parietals, and the frontal is un- divided. Koccu TRIBE. OF the two skulls of this tribe, one shows the hypertrophy of the cranial vault to a great degree, with much density of the thickened bone. The other skull measures in length 7 inches 3 lines (185°0), and in breadth 5 inches (127:0). Both are prognathous, and the malars are slightly promi- nent: in one skull the nasal bones project, in the other they are flat. KHAMPA TRIBE. This skull shows large and prominent nasals, continued, without indent, from the frontal bone, slightly prominent malars and maxillaries, with a low and narrow forehead, and the following proportions of cranium :—length 6 inches 10 lines (175-0), breadth 5 inches 6 lines (140°0). The parietals join the alisphenoids, and the frontal is undivided. Bacnatu TrrBeE (Nepal proper) (2 skulls). One of these skulls is of an adult, the other is of a child. The jaw, in the adult, is slightly prognathous; the malars are slightly inclined outward ; the nasals are moderately prominent; the forehead is low and narrow. The length of the cranium is 7 inches (180-0); the breadth is 5 inches 6} lines (142:0). In other characters this skull resembles that of the Khampa tribe. SyMBHUNATH TRIBE (Hill-man, probably Thibetan). The two skulls so marked differ singularly in the development of the nasal bones: in one (1 ¢) they are very long and prominent; in the other (1 d@) they are flat: in the simious variety the malar bones are broad and promi- nent, and the jaw is broad and prognathous, giving a Mongolian aspect to the skull; the other skull conforms to Blumenbach’s Caucasian type. In the skull 1 d, the length of the cranium is 7 inches 1 line (180:0); the breadth is 5 inches 5 lines (137°0). The skull 1 e is about 3 lines shorter and 2 lines broader than the other. In both the frontal is undivided, and the alisphenoids join the parietals, the right alisphenoid in 1 ¢ being divided into three wormian bones. BAGNATH TRIBE (Nepal proper). The adult skull so marked is prognathous, with a moderate development of the nasal bones, and divergence of the malars at their lower part. The length of the cranium is 7 inches 1 line (180°0); the breadth is 5 inches 6 lines (139'0). The alisphenoids join the parietals, and the frontal is undi- vided. In the child’s skull the left squamosal sends forward a process dividing the alisphenoid from the parietals.) The suture dividing the mastoid from the squamosal is retained. MAN oF THE Piatns (Ganges: unknown tribe). This skull is prognathous, but with a good nasal development ; the malars are scarcely prominent. The length of the cranium is 7 inches 2 lines (183:0); the breadth is 5 inches (128-0). The alisphenoids join the parie- tals, and the frontal is undivided. This skull shows a strong occipital spine. Fakir (Bengal Islamite). This skull is prognathous, with a less nasal development, but yet good: a ON A SERIES OF NEPALESE SKULLS. 101 slight malar divarication, as if tending to the Mongolian type, with a low forehead. ‘The length of the cranium is 7 inches (1780); the breadth is 5 inches 3} lines (135°0). LowLanpbers (Caste unknown). In the series of 10 skulls so marked is shown the same extreme variety in the development of the nasal bones as in the Newar, Lepcha, and Bhotia series ; in a few they are as flat as in the West African Negro, and in a few they are very prominent. There is not the same range of variety in the shape of the cranium; it is moderately oval, with the forehead narrow, and low in most. In three specimens the length of the cranium is 7 inches (178-0), the least length being 6 inches 5 lines (165°0); the extreme breadth is 5 inches 3 lines (135°0), and this occurs in one of the larger skulls (1 ¢,¢,¢,¢). In this skull the frontal suture is persistent. All are more or less prognathous, but some of them less so than in the majority of the Nepal tribes. A skull marked ‘ Tarai’ (1 , k, k, k, &) and another (1 8, b, b, b, 6) show prominent or divergent malar bones: in the rest the Caucasian proportions of those bones prevail. Three of the above series of skulls show a produced nasal spine of the large lateral wormian bones, which form the sides of the interparietal half of the superoccipital element, OBSERVATIONS. The first general remark that is suggested by the series of 90 skulls above characterized is, that the size and capacity of the cranium, or in other words, the amount of brain, is not greater than that which is usually found in the uneducated and lowest class of day-labourers in this country and in Ireland ; and that this low development of cranium is associated with more or less prognathism. In all, the general size of the molar teeth accords with that of the white, olive, yellow, and red races of mankind. The next remark is suggested by the extent of variety which is displayed, not merely in the entire series, but in the particular tribes or families com- prising it. The long, short and pyramidal, and vertically flattened, forms of cranium are severally exemplified; just as, in skulls from ancient British places of sepulture, some are found which, “ from an unusual degree of narrow- ness of the calvarium and face, belong less obviously to the brachycephalic class than usual*,” whilst others show the platycephalic or the acrocephalic form+. These results of the experienced craniological observers, Davis and Thurnam, concurring with my own, teach us how deceptive any single specimen of the skull of any one tribe would be if viewed and described as exemplify- ing the cranial type of such tribe or family ; and it shows the value of such extensive collections as that made by the accomplished and indefatigable Resident at Nepal. * Crania Britannica, 4to. Davis and Thurnam, 6, 7 (7). t Ibid. 12 (4) “In this stone barrow, on Wetton Hill, presenting only rude flint instru- ments, British pottery, the primitive flexed position of the skeleton, and the short rude cist —therefore with every mark of the primeval period, and no element of remote antiquity -wanting—we meet with two separate and distinct aberrant forms of skull in interments of the same age,” 102 ; REPORT—1859. There are not more than two or three skulls in the entire series which would have suggested, had they been presented to observation without pre- vious knowledge of their country, that they belonged to any primary division of Human kind distinct from that usually characterized by craniologists as Caucasian or Indo-European: the majority might have been obtained from grave-yards in London, Edinburgh, or Dublin, and have indicated a low condition of the Caucasian race. Only with regard to the Bhotias, a mountain-race, one of which was marked ‘ trans nivem,’ could the Mongolian type be said to prevail. Where the skulls of any one of the Nepal tribes amount to from 6 to 10 in number, they present varieties in the proportion of length and breadth of cranium, in the development of the nasal bones, in the divarication or prominence of the malar bones, in the shape of the forehead, in the degree of prominence of the frontal sinuses, and projection of the supraciliary ridge, which would be found, perhaps, in as many promiscuously collected skulls of the operatives of any of our large manufacturing towns, and which would be associated with corresponding diversities of features and physiognomy. As my experience in the characters of human skulls has increased, so has my difficulty of determining therefrom the primary race or variety of mankind. I have examined skulls of white Europeans, showing, as strongly as some of the Nepalese skulls, the flat nose, prognathous jaws, and con- tracted cranium of the Ethiopian. Only with regard to the Australian and Tasmanian aborigines do I feel any confidence of being able to detect, in any single skull, offered without comment to scrutiny, the distinctive characters of arace. The contracted cranium, flat nose, prominent jaws, and more or less protuberant cheek-bones are associated, in the Australo-Tasmanian race, with a peculiarly prominent supraciliary ridge and deep indent between its mid-part and the root of the nose; and still more peculiar and characteristic is the large proportional size of the teeth, especially of the true molars. Upon what, it may be asked, does so close a conformity of character depend, which inspires confidence in the determination of race, by inspection of any single skull of the aborigines of the vast Australian continent and ad- jacent islands? It is probable that it depends on the degree of uniformity of the manner of life and the few and simple wants of those aborigines. The food, the mode of obtaining it, the bodily actions, muscular exertions, and mental efforts stimulating and guiding such actions, vary but little in the dif- ferent individuals. The prevailing simple and low social state, the concomi- tant sameness and contracted range of ideas—in short, the small extent of variety in the whole series of living phenomena from the cradle to the grave of a human family of that grade, govern, as it seems to me, the conformity of the cranial organization. In the woolly-haired Negroes of Africa there is greater range of variety of cranial organizution, concomitant with a greater range of variety in their modes of life and physical development. I believe it would be rash to pro- nounce on the Negro nature of any single skull, save of some of the lowest races of the west coast of Africa; because I have observed, previous to the present craniological comparison, that the assigned characters of the AEthio- pian cranium occasionally occur as fully developed in certain low individuals of other races; the subjects of the present Report afford similar instances. This experience has led to the inference that, in the ratio of the complexity of the social system, and of the diversity in the modes of sustaining life and . ‘spending it, is the range of diversity of feature and of cranial organization, It is probable, therefore, from the effects of civilization and social progress -in other varieties or families of mankind, that were the seeds of such progress ON THE PHOTOGRAPHIC IMAGE. 103 to germinate and take on growth in the Australian family, the uniformity of cranial character now prevailing would be concomitantly and progressively modified. It is certain that such modifications of cranial structure and feature, accompanying diversities in modes of life, detract from their value as distinctive natural-history characters of races of mankind. Supposing social progress to be possible in a race like the Australians, without admixture of other blood, a question of much interest suggests itself—in what degree and in what way the cranial physiognomy would be modified? By analogy I think it probable that the modification might, in the course of time, become at least as great as that which is observable in unmixed Negro races which for generations have been subjected to, and im- proved by, civilizing influences. Upon the whole, then, in regard to the immediate subject of the present Report, undertaken at the request of the Committee of the Ethnological Section, and performed on that account, as well as out of regard for my accomplished and scientific friend Mr. Hodgson, with much pleasure and the best of my leisure and ability, I must confess that the results are rather nega- tive than positive; but if they should suggest any improved views in the study and application of the physical characters of Man, the aim of the Section will not wholly have been unfulfilled. Report of the Committee, consisting of Messrs. Maskelyne, Hadow, Hardwich, and Llewelyn, on the Present State of our Knowledge regarding the Photographic Image. Tue chemical problem presented by the photographic image is one of great complexity. It is uninviting to the chemist in so far as it presents very little opportunity of his obtaining quantitative results; for howsoever subtle and rapid be the chemical transformation effected by the light, it consists, in most cases, of a superficial change only, and defies even the delicate methods of the balance. In undertaking to collect what is known and to test the correctness of what has been published regarding this intricate problem, the Committee have proposed to themselves to deal first with the simplest trans- formations on which photographic processes are founded, and to pass on from these to the more complex. Moreover they confine themselves to the photographic results obtained with the salts of silver, as these are the most employed, and because it is necessary to assign some limits to their inquiry. If the salts of silver are the most remarkable for their susceptibility to photochemical change, one is naturally led to search first for the causes of this among those simpler compounds of the metal in which the transforma- tion is not complicated by the secondary decompositions which might be expected to accompany it in the case of organic compounds. Yet among the inorganic compounds this susceptibility to photochemical decomposition is rare ; and though not absolutely confined to one salt, the chloride of silver, that body exhibits the simplest and one of the best illustrations of it. The chloride of silver, when perfectly pure, passes, on exposure to light, from its pure white through various stages of change in hue, in which blue is mixed with grey, until it finally reaches a deep slate-violet colour. Chlo- rine is evolved from the chloride; but the question which here meets us iz limine is one which probably underlies the whole of the problem we have to consider, and consists in the chemical condition in which the silver remains 104 REPORT—1859. after the light has completed the decomposition so far as it can go. Is the result a subchloride of silver? or are the chlorine and the silver completely dissevered, the gaseous element going away, and the metal remaining mixed with, or rather encrusting, particles of unaltered chloride ? Certainly the weight of authority is in favour of the latter view. Such, at least, is to be gathered from papers by Dr. Draper of New York*, by Mr. Guthrie+, and more recently from a series of papers by MM. Davanne and Girard, in France. In the first two memoirs referred to, an allotropic state of the metallic silver is viewed as the only explanation of the reactions of the dark substance formed by the light. No chemist, however, has yet produced this substance in such a state of purity as to be able to subject it to an analysis; and the only arguments, therefore, which can be relied on in explanation of the change are such as make the fewest assumptions and put the least strain on the present experience of the chemist. There have been many methods proposed for the production of a sub- chloride of silver by processes directly chemical. One of these consists in the suspension of silver leaf in a dilute solution of sesquichloride of iron, or of chloride of copper. But this experiment has been repeated by us, and we are compelled to look upon the purple-tinted product as chloride of silver accompanied by but a trace of a substance possessing a profoundly- colouring power, which, as will presently be explained, we believe to be a subchloride. In order to produce this substance with at all events a greater approach to isolation, we endeavoured to avail ourselves of the possibility of a reaction between chlorhydric acid and the suboxide of silver, and with this view in- stituted many experiments for the production of this last body in a state of chemical purity. Memoirs devoted to the chemistry of the suboxide of silver are not rare. Professor Faraday { showed that the deposit formed by the exposure to the air of an ammoniacal solution of oxide of silver, consists of a compound with a composition of 108 silver and 5°4 oxygen. This com- position is incompatible with a formula Ag, O (supposing oxide of silver to be AgO); but the physical characters of the body are interesting. It is grey, and by reflected light is seen to possess a strong lustre. By transmitted light a thin layer of it appears bright yellow. Rose § has called attention to various other reactions in which suboxide of silver appears to be formed. Thus, if ammoniacal solution of nitrate of silver be added to protosulphate of iron, a deep and intensely colorific black preci- pitate is formed, consisting of a compound expressed by the formula Ag, O, 2FeO, Fe, O,. Similar or analogous products of different composition are formed by the use of salts of the manganous oxide, and by solutions of cobalt; but in all these cases the suboxide of silver is associated in combi- nation with other bodies, and does not present itself in a state from which it would be easily convertible into a subchloride. Rose, indeed, has made one remark, in connexion with these researches, which has a significance of some value for the photographic chemist. He shows that, in the case of adding the acetate of silver to a protoacetate of iron, the precipitate presents the black tint and deeply colorific power which seem to characterize the com- pounds of the suboxide of silver. When the salts used, however, contain “strong” mineral acids, as when nitrate of silver and sulphate of iron are the mutual precipitants, the deposit is grey and metallic—the reduction of * * Phil. Mag. xiv. 322, tT Chem. Soc. Quart. Journ. x. 74. + Quart. Journ. Sc. iv. 268. § Journ, Pract. Chem. Ixxi, 215, 407 e¢ seg.; see also Wohler, Pogg. Ann. xli, 344, ON THE PHOTOGRAPHIC IMAGE. 105 the silver is, in short, complete. The significance of this fact we shall here- after recall. The processes which seemed to hold out the greatest prospect of success for the production in the first place of a suboxide, and subsequently of a sub- chloride, by the methods of the laboratory, and independently of the action of the light, were those afforded by the reduction* of the citrate of silver, and by the conversion of arsenite of silver> by the action of a caustic alkali into alkaline arseniate, accompanied by a reduction of the oxide of silver to a mixture of metallic silver and suboxide, thus: 3 AgO As O,+3Na 0 HO=$Na 0 AsO,+ Ag, 0+ Agt. Of the results yielded by the first of these, none were found that gave any promise at all satisfactory. Hydrogen was passed through citrate of silver suspended in hot water. The products, at first brown, and then black, and finally grey, were examined at various stages of their progress in coloration, citric acid being used as a solvent to remove the citrate and the oxide §, the residuary product being examined by treatment with dilute chlorhydric acid to convert it into chloride. The citric acid solution was found to contain nothing capable of reducing permanganate of potash, and must therefore have been free from suboxide. The result of treating the residue with chlor- hydric acid, and then dissolving the silver by dilute nitric acid, was a rose- tinted chloride of silver. On the supposition that this residue was a mixture of suboxide, or a salt of it, with metallic silver, we are constrained to the view that the suboxide of silver is not characterized by the property of entirely passing, under the influence of chlorhydric acid, into subchloride. This seems to be confirmed in some degree by the results with the arsenite, to which we now proceed. To that reaction, which Wohler has described, much attention was devoted ; and it was tried under several modifications ||. By forming a dilute solution * Wohler, Ann. Pharm. xxx. 3. + Wohler, Ann. Chem. Pharm. cl. 363. + The formula for arsenite of silver usually accepted is 2AgO AsO3, but we find Wohler’s formula as above given to be the correct one. § The brown product became converted into the black one by the treatment with citric acid, Both underwent similar changes under the successive action of chlorhydric and nitric acids, and both previous to this treatment reduced the permanganate of potash powerfully. But it was found that the citric acid alone was capable of reducing the deposit to the grey condition of metallic silver, withdrawing from it at the same time (all the) oxide of silver,—a result which seemed to render almost hopeless the effort to form the suboxide by its means. Indeed the mere boiling of the citrate blackened it, producing a dark-coloured mixture of silver with some compound of the suboxide, the citrate itself undergoing a transformation which must have lowered its saturating power, as the solution remained neutral. The citrate, however, when thus boiled with water through which a stream of hydrogen was passing, be- came more darkly coloured, but imparted an acid reaction to the water. The black body that results from the reactions described, contains organic matter, as it intumesces when heated. It cannot therefore be merely a mixture of metallic silver with the suboxide.. The dry citrate heated in a stream of hydrogen is very slowly affected at 212°, but passes at length into a substance which produces on the one hand a dark-brown solution, and on the other a brown residue which yields a very pale-red body on being transformed by chlorhydric and nitric acids. || It appeared, in trying Wohler’s experiment in several ways, that on the one hand it was extremely difficult to get rid of all the arsenic compound from the residue, and on the other that the tendency of arsenic acid in solution was to further the breaking up of the suboxide into oxide and metal. Lime- and baryta-water were therefore substituted for the soda, but still arsenite of silver remained undecomposed. This seemed due to its solid condition, It was to overcome this that the solution in nitric acid was adopted. ' It was found, however, that the chocolate-tinted compound of chlorine and silver, by what- ever process it had been produced, became, by fresh treatment with chlorhydric acid, again 106 REPORT—1859. of arsenite of silver in nitric acid, and adding this very gradually to a boiling concentrated solution of soda, an extremely black powder was produced. This on being treated with dilute chlorhydric acid becomes grey ; and on boiling the washed product with dilute nitric acid, silver is dissolved, and there is left a substance, which, if Wohler be right in calling the black pow- der suboxide of silver, we should expect to contain subchloride of silver. The colour of this substance is a rich chocolate or maroon, more or less dark, according to the nature of the process: it never reached the deep slate-violet of the chloride of silver exposed to sunlight. On analysis it was found to contain as large an amount as 24 per cent. of chlorine ; The pure chloride Ag Cl contains 24°74 of chlorine ; The subchloride Ag, Cl requires 14°08 of chlorine. Other products of less-deep hue than the one first examined gave the numbers 24°3 and 242 per cent. of chlorine. Assuming that the chocolate hue was imparted to the substance by a subchloride (and no other view seems equally probable), we are constrained to recognize in this subchloride, only present to the amount at the furthest of 5 per cent., a surprising colorific energy. From the experiments previously cited, we are disposed to think that our failure in this attempt to produce the pure subchloride of silver arose from the fact of the action of chlorhydric acid upon the suboxide of silver not being so simple as a complete conversion into subchloride would indicate; and we are the more induced to draw this conclusion from the analogy of the sub- oxide of mercury. Thus, if from a solution of the suboxide of mercury that oxide be precipitated, the action of chlorhydric acid on the precipitate is not to form the subchloride, but a grey mixture of chloride and metallic mercury. The same may perhaps apply to suboxide of silver ; and, if so, it would be decomposed by chlorhydric acid, either partially or entirely, and would form chloride of silver and metallic silver. One experiment we tried, in the hope of producing the subchloride of silver by a direct reaction. Chloride of silver is soluble in concentrated and highly alkaline arsenite of soda; and this solution, in the presence of excess of soda, was gently warmed. A brilliant mirror-like deposit, not of sub- chloride, but of metallic silver, was the result. But with however little success the efforts to produce a pure subchloride of silver have as yet been crowned, the experiments we have detailed enabled us to institute a few comparative reactions whereby the result of treating a true subchloride (however diluted, so to say, with protochloride) with the ordinary reagents employed by the photographist may be achieved. The results yielded by these reagents were the following :— Nitric acid, of sufficient strength to dissolve silver by heat, does not alter this dark compound. Chlorhydrie acid does not, when dilute, produce any apparent change in it. Ammonia breaks it up entirely, dissolving all as chloride, except a minute amount of metallic silver, which remains. Hyposulphite of Soda dissolves all except a trace of metallic silver like that left by the ammonia. It will hardly be worth while to go through the reactions exhibited by capable of yielding a solution of silver when treated by nitric acid. So utterly unstable are these subcompounds of that metal! Indeed it would seem that to secure to them any permanence, they must be formed in combination, - ~ . , ON THE PHOTOGRAPHIC IMAGE, 107 these several tests with the dark body formed by the photochemical decom- position of the chloride of silver, or of this body mixed with excess of nitrate ; for we find that these reactions are in the several cases identical. The light- darkened chloride indeed presents a deeper and bluer colour than that formed artificially ; but when it is considered that the light-formed body is a coating of uniformly and completely transformed substance—superficial it is true, but continuous in its surface—while the laboratory product is an intimate mix- ture of discontinuous particles, the bluer tint of the one and the redder tint of the other will hardly carry much weight in deciding against the identity of the colorific silver-compound in each case. Nor will it perhaps be con- sidered to support the view of the photochemical reduction consisting in the complete severance of the metallic silver, that the product of that reduction can be formed by the light in the presence of nitric acid. The production of an allotropic form of silver in the nascent state, in the presence of nitric acid, seems certainly to make a larger demand on the credulity of the che- ‘mist than the assertion that the reduction stops at an intermediate stage, at which a subchloride is the result of it—a subchloride, whose properties we have seen to be identical with those of a substance formed in the laboratory, and to which it is difficult to assign any other composition than that of a subchloride of silver. In the photographic processes in which the chloride of silver is employed, it is to be borne in mind that the chloride of silver is not used by itself—nay, by itself is quite inadequate to the production of the deep colour requisite for photographic effects. It is used in fact always in conjunction with nitrate of silver, and also, it must be added, with organic substances, among which the cellulose of the paper and the glue-like size are prominent, The action of the nitrate of silver needs little explanation; it supplies continually a fresh surface of chloride of silver, formed by part of the chlorine given off from the surface of the original chloride, which unites at once with the silver of the nitrates, and simultaneously becomes blackened by the action of the light. It is singular, however, that it has escaped the observation of the chemists who have experimented on this point, that an oxide of chlorine is also formed at the same time, as may be shown by the renewed deposit of chloride of silver which is produced in the supernatant nitrate by the addition to it of sulphurous acid, That the darker compound produced by the presence of ni- trate of silver is in no respect different, save that it is a more abundant deposit, from that formed from the chloride alone, is evidenced by the identity of its reactions with those of the latter. For here, again, dilute nitric acid of suf- ficient strength to dissolve silver at 112°, is inert in its action on this bluish- black compound. Chlorhydric acid, if not sufficiently dilute, renders it somewhat paler, and gives a brownish hue to its slaty violet, but otherwise does not alter it. Hyposulphite of soda dissolves nearly the whole if suffi- ciently strong, leaving but a trace of metallic silver ; and ammonia acts in a similar manner, while cyanide of potassium appears entirely to dissolve it. In order to be satisfied that the bluish slate-coloured substance formed in the presence of nitrate of silver by the action of light on the chloride was not an oxychloride, an attempt was made to form such an oxychloride by operating on the chocolate-coloured substance so often alluded to, Boiled with caustic potash, this became dark brown; but nitrie acid restored to it its chocolate tint. The substance operated on in this experiment was formed from the citrate by the action of hydrogen (in this case in the presence of nitrate of silver), and treatment of the products as before, by chlorhydric and nitric acids in succession. We consider that we are justified in drawing the following conclusions :— 108 REPORT—1859. 1. That the action of the light on chloride of silver is to reduce it, in so far as it is able to penetrate its substance, to the state of a subchloride. 2. That in the presence of nitrate of silver, this deposit of subchloride is necessarily more plentiful, while some part of the liberated chlorine passes into an oxide, which prevents a portion of the chlorine set free from con- ducing to the formation of fresh subchloride. From this point we may proceed to the discussion of the photographic image in more complex, but, for the photographist, more available forms. And in doing so, we must at the outset bear in mind that the image varies in its character in different stages of the photographic process. ‘The first result obtained by the light, even if it be the same in all stages of the solari- zation, is not the result which is in many cases left after the fixing solution has performed its work; but it is perhaps more interesting, as indicating the nature of the change effected by the light, independent of the chemical re- agents which are afterwards applied. In endeavouring to reduce into orderly arrangement the great number of photographie results which this inquiry involves, it seemed best to sever at the outset two series of them which bear but little relation to each other,— namely, the images obtained by development, and those which are formed visibly by the light. Commencing with the latter of these, the attention is at once arrested by the processes involving the use of chloride of silver in conjunction with the nitrate of that metal. The rationale of the union of these two compounds for the production of an effect far greater than that upon the chloride alone, has been shown ; but, practically, in photographie processes there are other agents present in the paper, or purposely introduced into it, which play a part in the photochemical change hardly less important than that of the silver salts tiiemselves.— We may fairly inquire in the first instance whether the presence of the fibre of the paper itself may not assist in effecting decompositions under the influence of light. To determine this point, Swedish filtering paper, as the type of the most uniform and pure fibre of paper that could be procured, was treated with nitrate of silver alone: on being exposed for some hours, it exhibited a pale-reddish stain, which after several days’ insolation reached no deeper tone than a brown. The substitution of ammonio-nitrate of silver for the nitrate gave a rapidity to the change, and ultimately a depth of opacity to the result, by affording an antagonism, as we suppose, to the influence of the nitric acid. The reactions of the darkened ammonio-nitrate paper are as follows:—Ammonia does not otherwise affect it, than that treatment there- with (probably by action on the tissue of the paper) makes it slightly more readily acted on by other reagents. Nitric acid, though exceedingly dilute, rapidly dissolves it. Indeed an acid so far diluted that it took many hours to destroy the substance left by treating with ammonia Swedish paper that had been prepared with chloride of silver and subsequently darkened in the sun, was able to destroy this bronzed image formed by the ammonio-nitrate in a few minutes. Cyanide of potassium in presence of air rapidly destroys it, but not so rapidly as it does the image on chloride of silver just alluded to. It would be difficult, from the above reactions, to come to any positive opinion on the nature of the photochemically changed substance left by the ammonio-nitrate of silver on pure tissue of paper. But that this tissue is not without a part to play in the changes which the oxide of silver under- . goes, perhaps even a more important one than that of an absorber of oxygen, seems indicated by one curious experiment. Swedish filtering paper treated with nitrate of silver, and while still moist touched with a solution of proto- sulphate of iron, gives a grey stain easily recognized as metallic silver. When, - ON THE PHOTOGRAPHIC IMAGE, 109° however, it is suffered to dry (of course in the dark), the stain thus formed, instead of a grey, exhibits a dense black tone, which immediately afterwards passes on into a brown. The former of these is probably suboxide. But if the tissue of the paper is not to be altogether excluded from the list of possible cooperative agents present in these processes, there are other substances of which the influence can be demonstrated in a manner quite satisfactory to the photographist. Gelatine as size was long employed with- out his being conscious of its importance; and he now uses albumen as a photographie glaze, and sometimes other substances, such as grape sugar, Iceland moss, caseine, &c., on account of the fine tones and permanence in the fixing bath which they impart to his pictures. Gelatine and albumen both combine with nitrate of silver; and the character of the combination is one which chemistry has yet to explain with completeness. ‘These compounds differ from each other in many important respects: we shall select that with gelatine for illustration. The characters of the compound of gelatine and nitrate of silver are exhibited by the following statements. If a sheet of transparent gelatine be floatedupon a solution of nitrate of silver, the solution loses a considerable amount of the dissolved salt. When the proportion of the gelatine to the bulk and strength of the solution is suffi- cient, free nitrate of silver is scarcely to be detected in the bath, and what silver is found there is probably in the form of a gelatine-compound, which is not entirely insoluble. The gelatine mass, though but slightly soluble in cold, is so to a considerable amount in hot water, and retains at once the neutrality and the taste of the nitrate. The solution gives the following re- actions :— Caustic potash throws down a bulky olive-brown precipitate, which clots into a tough extensile mass. This dissolves by boiling with excess of the precipitant, yielding a very dark, and when diluted, a clear yellowish-brown solution. Strong ammonia produces no precipitate, but on boiling forms a pale orange-yellow solution, on which the light produces little or no change. Chloride of ammonium, introduced cautiously, produces no precipitate, but in excess renders the solution turbid. The clear liquid is not rendered tur- bid by boiling; but a few drops of nitric acid, if the temperature be raised to the boiling point, suffice to render it milky from separation of chloride of silver, which may be redissolved by ammonia, or darkened by the light. Iodide of potassium, unless carefully introduced, throws down a turbidity of a yellow tint, in it. But if this be removed by filtration, it will be found that the addition of the most dilute nitric acid and boiling throws down a fresh amount of iodide of silver. Cold nitric acid produces no change in the gelatino-nitrate (?) of silver, even when formed from the ordinary commercial gelatine; but boiling throws down sometimes a small quantity of chloride, originating in the impurity of that body. Chlorhydrie acid in minute quantity produces also no precipitate until boiled, when the chloride of silver separates from the compound. _ The gelatinous mass, formed by the action of the nitrate of silver solution upon the gelatine, becomes, on exposure to the sunlight, of a red colour. The change is a rapid one, and is accompanied by a shrinking of the mass to its original character of a thin sheet as it dries. The colour attained by prolonged solar influence is by transmitted light a deep ruby, and a “bronzed ” green by reflected light. Sheets of the gelatino-nitrate of silver thus solarized no longer swell up or dissolve in boiling water, but only after long boiling become disintegrated in filmy fragments. Potash gives, on boiling, a clear 110 ~~ * REPORT—1859. © solution, which even when dilute is brownish-red, and appears opaque when” concentrated. Ammonia added to this liquid diminishes its opacity and gives it an orange hue. In inquiring what the character of the change effected in these bodies is, we would direct attention to a process analogous to that by which the citrate of silver was examined. If hydrogen be freely passed over the albuminate of silver in a water bath, this becomes converted into a red body resembling in all essential particulars the red substance into which the light converts the same albuminate. In each case the reaction with the different tests is the same. That, in fact, a suboxide is in each case formed, and that this sub- oxide is in combination with the albuminous or gelatinous substance, seems the natural conclusion from what has preceded, no less than from the re- actions of the bodies themselves. The silver cannot be there in the metallic form; else, why should potash dissolve it, and why should ammonia convert it into a paler body? More- over, metallic mercury does not amalgamate with it. One reaction, indeed, might be urged as militating against this view. The hyposulphite of soda has but little action on the red compound, whereas it dissevers the consti- tuent elements of suboxide of silver as dissolved oxide of silver and residuary metal. But we have shown that silver is not entirely precipitated from its gelatinous nor from its albuminous compound by such tests as chlorides or iodides, and one will hardly therefore see with wonder that the albuminate or gelatinate of the suboxide resists the action of the alkaline lyposulphite. Nor would it be out of place here to hint, as our colleague Mr. Hardwich has done, at the high probability of the suboxide of silver associating itself with organic substances such as cellulose, albumen, gelatine, &c,, in a manner ana- logous to that in which other metallic salts, in which the saesallin element is not entirely saturated by metalloid elements, act the part of conjugate bodies, annexing themselves to the organic substances alluded to, and to colouring matters of various kinds. The action of these mordants belongs still to an obscure chapter of chemistry, but it is highly probable that the compounds under consideration are closely allied to them. Finally, we have to bear in mind that the fixing agent modifies the image formed by the light in the materials we have been considering. The alkaline hyposulphite, like ammonia, acts on the subchloride or the suboxide of silver, splitting the one into metallic silver and chloride which becomes dissolved, and the other into oxide and metal. Obviously the conversion of an image formed of either of the intensely colorific subcompounds of silver into a pale metallic deposit containing only half the amount of metal, and possessing none of the remarkable colorific energy of the suboxide or subchloride, is a conversion that can only be ex- pected to exhibit a great loss of tone. Practically the singular immunity from this dissevering action which the organic matter, combined with or conjugated to the subcompound of silver, extends to that subecompound, comes in to help the photographist from losing the beautiful result which the light itself pro- duces. And what little he still must lose he can almost restore again by the remarkable toning methods which he has recourse to. The rationale of these toning methods is to be sought in the chemistry of each different process. The deposit of gold from a solution of that metal is in its broad features a simple reaction—a deposit of a more electro-posi- tive metal in substitution of one less so,—but the precise details of each method of using a gold toning-bath doubtless involve more refined chemical explanations. Without attempting to go into these, we would invite atten- tion, however, to the sulphuretting baths by which this toning is sometimes ON THE PHOTOGRAPHIC IMAGE. i1i éonferred on the pictures. Sulphide of ammonium converts the fixed image on paper into, first, au intensely black compound, and subsequently, by its con- tinued action, into a dull yellowish, scarcely visible stain. The latter, there can be little doubt, is sulphide of silver. It seems highly probable that the inter- mediate step in the process is the production of a subsulphide, and that it is at that stage that the progress of sulphurizing is arrested in a successfully-toned picture. This explanation would be quite in harmony with the conditions under which the toning is performed. The results, then, at which we conceive that photographic chemistry may be said to have now arrived, in respect to the direct processes involving the use of silver-salts, may be thus stated. The materials employed perform various functions :— Ist. One of these is that of supporting the picture, as a mechanical material or basis for holding the chemical bodies. Of the substances so employed the tissue of paper is one. Pyroxyline (the product of a substitution effected in the elements of the cellulose) is spread on glass to afford another. The latter appears to be inert. The former, on the other hand, seems to aid in the reduction, and possibly in some cases to remain in union with the reduced result. Qudly. The silver-salts employed, whereof the chloride—for which may be substituted other salts, as the tribasic phosphate, the tartrate, the citrate, and many others, though each with a specific effect—appears to act by im- parting sensitiveness. The nitrate, on the other hand, is present in excess to keep up a constant succession of sensitive material, and so to give vigour and intensity to the image. 3rdly. Gelatine as a size, or albumen as a glaze, and various other sub- stitutes for these (though but little linked together by any chemical analogy amongst themselves), cooperate by conferring rich tints and deep tones, while they at once impart to the image formed on them:an immunity from the destroying action of the fixing process, and form a mechanical surface more or less impenetrable, which prevents the other sensitive compounds from sinking into the paper. Each of these substances can, provided nitrate of silver be present, be employed to produce an image. Thus, the chloride rapidly produces a faint picture ; the “gelatino-nitrate” slowly yields an intense one; together they produce the required result. Whether that result is a cumulative one, the sum of the separate results, or a conjoint one produced by a combination of the chloride with the gelatine compound, it were difficult to say. The image is, however, a mixed one, for treatment of it with dilute nitric acid leaves the slaty violet subchloride of silver. It seems therefore to be a mixture of subchloride with a gelatinous, and perhaps also a cellulose-com- pound of suboxide of silver. The next great division of our subject which we have to enter upon is that of photographs produced by development. Fortunately, in dealing with the images thus formed, we are able to dis- sever the results from the magic influence that calls them into being. We need only show that certain conditions are necessary for the impress of the invisible image ; we are not called on to explain the character uf the impress itself. Without attempting to explain what goes on in the camera obscura, we may determine the conditions for a favourable action in it, and interpret the results of that action after development; though even here, from the great delicacy of the processes employed, the task is a most difficult one. With regard then, first, to the preparatory portion of these processes in- volving the production of the sensitive surface. This consists, in the pro- 112 REPORT—1859, cesses on glass, in a supporting film, and generally in iodide of silver formed under conditions in which nitrate of silver was in excess. There are also generally present other ingredients, such as certain forms of organic matter, and in some cases bromide or even chloride of silver. That it is not a matter of indifference whether the supporting basis, or film, consist of pyroxyline, or albumen, or gelatine, or of these severally com- bined with other bodies or with each other, one might readily suppose from what has been already said under the head of direct processes; and it will be no difficult matter to show more than a probability that this is not due to a “molecular,” but to a “chemical ” distinction in the action of these bodies. The usual sensitive surface contains, if it does not consist in, iodide of silver with an excess of nitrate. But there are processes in which the plate is studiously washed with water to remove the nitrate, whereby, though it is impaired in sensitiveness, it retains enough of that quality for the produc- tion of excellent results. Though this retention of a susceptibility to the in- visible impression has been attributed to mechanical causes, such as the state of division of the iodide, the porosity of the film, &c., the following facts seem to favour a chemical explanation. Pure pyroxyline united with pure iodide and nitrate of silver, from which the nitrate of silver has subsequently been removed, and the film dried, is not susceptible of quick development after exposure in the camera; a mere trace of albumen introduced before the removal of the soluble silver-salt, however, prevents its entirely losing this sus- ceptibility. Gelatine, certain forms of sugar, resins, and various other bodies widely differing from one another in point of chemical character, possess a similar property, though the precise regulation of the processes employing them can hardly be said to be as yet mastered by the photographist. The products of decomposition contained in “old collodions,” and some of the fresh preparations of pyroxyline, in which secondary products are not studi- ously prevented from being formed, would seem to share this power with the classes of bodies referred to. But a question of the utmost interest to the scientific inquirer is involved in the chemistry of the iodide of silver; first, in respect to its power of forming combinations with the nitrate of silver, and secondly, as regards the probability of these combinations forming photographic compounds with the albuminous and other bodies alluded to. That the excess of nitrate of silver which is necessary in the first prepara- tion of all the sensitive films does not act the same part as that excess does in the case of the chloride in direct processes, will be evident at once, inas- much as the iodide of silver does not undergo reduction in the manner that the chloride does. In searching, therefore, for an explanation of the necessity of free nitrate, the mind naturally dwells on the compounds shown by Schnauss* and A. Kremer+ to be formed by the action of strong solution of nitrate of silver on the iodide. Although the production of these bodies in any quantity and in a state of chemical purity needs conditions not present on the photographic film, yet there seems little doubt that, as iodide of silver is dissolved by the nitrate, traces of these remarkable compounds can readily exist in the films containing these two ingredients. If so, the highly photographie character of the compound containing 2:8 per cent. of iodide of silver described by Kremer, and the fact of these bodies being decomposed with the separation of iodide of silver by the action of water, are facts of high interest to the photographic chemist, and seem to throw con- * siderable light on the hitherto obscure processes in which iodide of silver is * Archiy der Pharm. xcii. 260, + Journ. fiir Prakt, Chem. Ixxi. 54, ON THE PHOTOGRAPHIC IMAGE. 113 employed. These two facts, indeed, may be held to explain, very nearly, the character of the ordinary collodion process, but they do not explain the “preservative” processes in which the sensitiveness of the film is, within certain limits, retained by the introduction of albumen, gelatine, resin, sugars, or other organic substances, to the numbers of which experience is con- tinually adding. For the explanation of the action of these substances, we must recur to the facts already cited in the case of gelatine when used as a size in the direct processes. Thus, too, a plate coated in the ordinary manner with albumen containing iodide of potassium dissolved, will be found, on being raised from out of the silver-bath, not to be opake, and coated with a dense deposit of iodide of silver, but to appear highly translucent and opalescent in its cha- racter, and that, even though the iodide be introduced with a liberal hand. In fact, the albumen is present not merely as a mechanical vehicle for the sen- sitive materials, but can be proved to have combined with those materials, and to play no insignificant part in their photochemical transformation. That this is so, may be at once shown by adding some albumen to a quantity of the ordinary “silver-bath,’—say the white of one egg, diluted with 13 ounce of water, added to 40 ounces of bath. The iodide of silver with which the bath was previously saturated will be found in it no more; it is now to be looked for in the gelatinous precipitate which the albumen has formed. The precipitate is in fact a chemical compound of albumen with nitrate of silver holding in combination the iodide. This is, as might be sup- posed, from what has been said of the albuminate alone, a highly photographie compound. We have stated that a similar compound is formed by gelatino- nitrate of silver and iodide of silver. Citrate of silver, glycyrhizine, and many other bodies share with these substances, and the first two possess even in a far higher degree than they, the property of carrying down in a com- bination—or, so to say, in solid solution—the iodide of silver, and forming with it highly photographic products. A hiatus must needs occur in this stage of our inquiry. The sensitive film is exposed in the camera, and in a few instants the invisible image is impressed. We remove it, and our task begins again at a tangible starting- point. The development of the image is the visible evidence that the light has been at work, and a close examination of the nature of this image is the only further key we possess to elucidate the character of the light’s action. By a comparison of the developed images formed on plates that have been exposed for the correct time to produce a good picture, with such as are produced by the direct action of the light, we arrive at two conclusions. First, a general similarity in the appearance of the various sorts of images by each method is observable; but, secondly, the deposit in the case of the developed image is far more abundant than that in the direct image. The comparison as regards the quantity of deposit in any two images is one far too delicate to be effected by the balance ; but a method of instituting such a comparison with great accuracy is founded upon the ready conversion of any such images into sulphide of silver, a body transparent and yellow in thin layers, but passing through tones of sepia to almost a black opacity as the thickness is increased. The colour becomes thus a good means of com- paring any two deposits, and the complete conversion of these into the sul- phide is ensured by the use successively of chlorine-water and of sul- phuretted hydrogen. A similar comparative result may be obtained by sub- stituting the chloride of mercury for the chlorine-water. Now the deposited images in the case of the processes by development present some points of great analogy to those formed in the direct processes ; 1859. I 114 REPORT—1859. in others these images widely diverge from them. Thus, we seldom find in them those purple and violet tones which seem to characterize the subchlo- ride of silver before fixing. On the other hand, we observe two classes of developed images :—the one is of a dull metallic appearance, of a slaty grey character by transmitted light, and in but a feeble degree opake; the other varies in colour, exhibiting brown or red hues, and sometimes even presenting perfect opacity to transmitted light, closely similar to the picture formed by direct processes. But, on testing these two varieties of image by the method of conversion into sulphide of silver before described, it is found that the dull translucent metallic image teems with silver, and becomes very opake in the form of sulphide, while the more richly coloured and dense-seeming image loses opacity under the sulphurizing action, and exhibits at last a subdued tone of colour that brings it more on a par with the sulphuretted metallic image. Clearly then, here, density, and the qualities which give photographic value to an image, do not depend on the amount of metal that goes to form it, so much as on the chemical, and even perhaps mechanical state, in which that silver is present in it. The several causes which determine the deposit of the images in these several states appear to be these :— 1. The materials forming the sensitive film.—Pyroxyline, in chemical purity, has little tendency to form the darker image. Albumen and the hete- rogeneous substances (including decomposed collodions), which we have had to yoke in the same class with it, have this tendency. In general (speaking of the ordinary moist process) the tendency to pro- duce the darker image is found to be in something like an inverse ratio, ceteris paribus, with the sensitiveness. The use of the bromide of silver with the iodide imparts to a collodion film a tendency to deposit the grey metallic image, at the same time that a more powerful reducing agent is needed to develope it. It is a remarkable fact, bearing upon this singular property of bromide, that no compounds ana- logous to that formed by A. Kremer with the iodide have yet been formed with it. In the case of albumen, this influence of bromide is not felt; for with albumen, bromide of silver is held to increase the opacity of the image. 2. The nature of the developing agent——The substances used to develope the latent image, besides the free nitrate of silver invariably necessary, embrace also without exception one ingredient, the character and the pur- pose of which is to reduce the salts of silver. In some cases organic bodies are employed for this purpose, in others the reducing agent is inorganic. Now, whether the grey or metallic form of image is completely reduced silver, and the more opake forms are an argentous compound (mixed or not with metallic silver), or whether all the forms of image are silver in different mechanical states of deposition, is a very important inquiry, and one on which the facts of the development and the nature of the developing agent may throw some light. But no one who is intimate with the complex and perplexing details of this step in the photographic process will expect the chemist to come in and remove the difficulty by the use of a few formule. All we can hope to do is to point to a few sure results of experience, and indicate any explanation which may be suggested by facts from the laboratory analogous to these. It is known, then, that to produce a “ positive” picture in the camera, the developing agent should be sulphate of iron, acidified in some cases even by . nitric acid. The result is the crystalline white deposit of metallic silver. Protonitrate of iron is used with a similar result. So likewise in the labo- ratory it is known that a neutral.mixture of the ferrous sulphate and nitrate ON THE PHOTOGRAPHIC IMAGE. 115 of silver forms the grey deposit, but that the addition of a little acid pro- duces the white and brilliant form of the metal. If now we would take a result opposite to this from the experience of the photographist, we may select an ordinary collodion plate prepared by the usual negative process, and we shall find that protacetate of iron developes the image of a black colour. Now Rose, in the remarkable experiments on the production of argentous compounds with the higher oxides of iron, &¢., to which we have called attention, shows that whereas the argentic salts con- taining strong mineral acids are precipitated as grey metal by ferrous salts containing similar acids, the deposit formed by uniting the ferrous oxide and the argentic oxide, or the compounds of these with organic weak acids, con- tain the suboxide of silver and are black. When to this is added the circumstance that the white and grey photo- graphic images are with facility amalgamated with mercury, but that the coloured and black images are not, it may be treated as a matter of high probability that the black and coloured images are formed by compounds of the suboxide of silver. A directive energy is exercised upon the nature of the deposit by the various kinds of organic matter employed in the development. These all seem to restrict the limits of variation to the dark bluish-black (given by citric acid when present), on the one hand, and various reds and browns upon the other; while, again, the presence of the albuminous and other substances, so often before referred to, is, as was above remarked, a sure means of forming these darker and coloured images. Indeed, albumen will determine such images notwithstanding that even free nitric acid be present with it. If it be a suboxide that causes the dark precipitate, that suboxide must go down in combination, and so resist the action of the fixing solvents, But, 3. The character of the light has also a remarkable influence in inducing a grey or a dark character on the developed image. If the picture has been produced by an intense light, as by a lens of large aperture, or as in the case of an exterior as contrasted with an interior view of a building, or as on a dull, misty day in contrast with a bright and sunny one, it will be found that, ceteris paribus, the tendency of the weaker action of the light is to allow the reduction of the silver in the metallic form. On the other hand, the more intense light has given to the molecules of the sensitive film a controlling energy which they exercise on the deposit, and which appears analogous to that of the light in the direct process, in its modifying the reduction and giving it the form of a production of an argen- tous compound; as though the iodic compound became in a certain sense phosphorescent to the chemical rays of the light, and operated on the mixed silver-salt and reducing agent as they float over it in the manner that the direct light might be supposed to do. Of course, the materials must be nicely balanced, as regards their tenden- cies to produce the black or the grey images, for the peculiar action of an intense or a weak light to be made fully evident. Albumen or powerful organic agents will usually destroy this balance. One fact remains to be observed. Whatever may have been the character of the first particles deposited on the plate, that character will be maintained thenceforward, and fresh deposits may be, so to say, piled upon the first by the singular agglutinative tendency of crystalline deposits, so long as the neces- sary conditions of fresh silver solution and of fresh stores of the reducing agent be supplied to keep up the action. Our task has been, by an investigation of the chemistry of the image in its different varieties, to afford some data, at least, by which the further step 12 116 REPORT—1859. may be hereafter taken of determining the precise character of the photo- chemical agency, to whose marvellous influences art owes so many beautiful results, and science is indebted for more than one intricate problem. Report of the Belfast Dredging Committee for 1859. By Georce C. Hynpman, President of the Belfast Natural History and Philoso- phical Society. Tue Committee appointed at the Meeting of the British Association at Leeds, to proceed with the investigation of the Marine Zoology of the north and north-east of Ireland, consisted of Mr. Patterson, Dr. Dickie, Dr. Wyville Thomson, Mr. Waller, and Mr. Hyndman, who took measures to commence their operations early in June, from which time till the end of August various explorations were nade along the coast and in the sea adjacent, extending from the south side of Belfast Bay (county Down) to the deep water north of the Maidens on a line with Glenarm (county Antrim). Those acquainted with dredging operations will understand the difficulties and delays to which such work is liable, calms and storms equally interfering with progress. At the first meeting on the 7th of June, the weather was too fine to enable the party to reach the desired ground in due time; the few specimens of living Brachiopoda then obtained were forwarded to Mr. Han- cock, who has been engaged in the investigation of that tribe, but owing to his absence from home the opportunity of seeing them alive was lost. Ona second occasion, 22nd of June, the party engaged a steamer and succeeded in reaching the chosen ground for dredging in the deep water off the Maiden Islands, when a sudden storm arose, more violent than usual at that season, which obliged them to cease work and make for the shelter of land with all expedition, glad to save their ropes and dredges. A boat belonging to a ship of war then in Belfast Bay was not so fortunate, being upset in the squall, by whieh lamentable occurrence several men were drowned. During the season the Committee were assisted by the co-operation of seve- ral gentlemen who took an interest in their work. In August, J. Gwyn Jeffreys, Esq., visited Belfast, and made one of a party for dredging off Larne, where a fortnight was spent in examining the coast and deep water adjacent, extending as far north as opposite to Glenarm. Mr. Jeffreys’ experience and acuteness in discriminating species were of great service in adding to the lists and correcting some previouserrors. During this period a steamer was again engaged from Belfast, which enabled a number of gentlemen to join in the labour and rendered good service. It was originally contemplated to extend the investigation as far as Rath- lin Island, but want of time and other circumstances prevented this from being accomplished. Very comprehensive lists having been already published in the Reports of the British Association for 1857 and 1858, it is thought needless on the present occasion to do more than record such additions as have been made, with any further information that may be considered interesting regarding some particular species. List of Species referred to in the Report of the Belfast Dredging Committee for 1859. Philine quadrata, dead. In 80 fathoms off the Maidens. Amphisphyra hyalina, dead. With the last. BELFAST DREDGING COMMITTEE, 7, Cylichna Lajonkaireana (Baster). From the Turbot-bank, dead ; determined by Mr. Jeffreys in Mr. Hyndman’s cabinet. Mangelia attenuata, dead. Turbot-bank sand, Mr. Waller. reticulata, dead. A single specimen of this rare and beautiful shell was found by Mr. Jeffreys in dredging from the deep water north of the Maidens. New to the Irish list. It is a southern form. — costata, var. coarctata, dead. Near the Turbot-bank. Fusus Islandicus, var. gracilis (Alder), living. In 60 fathoms, about six miles from the Gobbins. Buccinum undatum, var. striatum, Pennant; living. With the last. Cerithiopsis pulchella, dead. In Turbot-bank sand, Mr. Waller ; erroneously recorded in the list of 1857 as Cerithium metula. Trichotropis borealis, living. Turbot-bank. Lamellaria perspicua, living. In 80 fathoms north of the Maidens. This is usually a sub- littoral species. Natica helicoides, dead. A single young specimen by Mr. Jeffreys. Cerithium metula, of the list for 1857, was found by Mr. J. to be Cerithiopsis pulchella. In dredged sand, Turbot-bank. Euomphalus (Omologyra) nitidissimus (Skenea nitidissima), living on Zostera marina. Shores of Larne Lough. Skenea divisa, living. Off Larne, 1858, Mr. Hyndman. — planorbis, living. A small variety occurs in Larne Lough, has a more convex spire, and it appears to bear the same relation to the typical form that the Helix rupestris of Continental authors does to our H. umbilicata, Mr. Jeffreys. Jeffreysia Gulsone, dead. Turbot-bank sand. In Mr. Hyndman’s cabinet, determined by Mr. Jeffreys. Lacuna crassior, living. Coast of Antrim. Mr. Jeffreys observed that the shell has a distinct canal or groove in the columella, evidently showing its generic position. The animal, which he examined, settles the question. It is of a yellowish white colour, having two subulate and slender tentacles, with the eyes placed’on short peduncles at their external base ; proboscis long and narrow ; two rather long caudal filaments, one on each side of the operculigerous lobe. The creature is active in its habits, and seems fond of crawling out of water. — labiosa, Lovén, dead. In Turbot-bank sand, Mr. Jeffreys. Littorina fabalis, living. Found by Mr. Jeffreys on the shore of Larne Lough, and considered by him to be only a variety of L. littoralis. — tenebrosa, living. In the same locality as the last, and considered only a variety of L. rudis. Scissurella crispata, dead. A fresh specimen taken in 80 fathoms, 5 or 6 miles north of the Maidens. Margarita costulata (Skenea), dead. In Turbot-bank sand, Mr. Waller. Trochus Montagui, living. An exquisite scalariform variety found by Mr. Jeffreys and Mr. Waller off the coast of Antrim; the animal does not differ from that of the usual form. striatus, dead. In Turbot-bank sand, Mr. Jeffreys. Emarginula reticulata, living. In 80 fathoms north of the Maidens. Mr. Jeffreys found the fry, which closely resembles a Scissurella, and has a regular Trochoidal spire, with the edges of the slit inflected. Propilidium ancyloide, living. On stones and shells in 70 to 80 fathoms. They were of different sizes, the largest not exceeding one-eighth of an inch, and evidently adult. The Patella ceca of Miiller, of which the authors of ‘British Mollusca’ supposed this might be the young, appears to be a very different species, if indeed it belongs to the same genus. (J. G. J.) Patella athletica, living. Coast of Down, in Mr. Hyndman’s cabinet. Chiton cancellatus, living. Not uncommon in deep water. Hanleyi. A fine living specimen on a shell, and one on a stone in 80 fathoms. Argiope Cistellula, living. On stones as well as shells in the deeper water. Terebratula capsula, living. With the last. —— caput-serpentis, living. Of large size in the deep water. Some specimens kept living exhibited on the front margin a series of white filaments which appeared to protrude from the tubes of the shells, and not to be retractile when touched. Pecten opercularis. Mr. Jeffreys remarks that the young have a rhomboidal form, and the lower or flat valve is much smaller than the other (which overlaps it), and is perfectly smooth. The ribs do not at first appear on the larger valve, but are preceded by a shagreened reticulation. furtivus, alive. Taken in 1858 by Mr. Waller and Mr, Hyndman on both the Antrim 118 REPORT—1859. and Down coasts along with P. striatus. It was again taken this year, and at once distinguished by Mr. Jeffreys. Pecten Danicus, dead. A single valve in 80 fathoms. In the former list, 1857, with a mark as being doubtful. This proves Dr. Dickie to have been correct. Modiola modiolus, living. A small variety, three inches in length, occurs in deep water. The same at the Copelands. It is stated that specimens have been found on the West coast of Scotland, seven or eight inches long. —— phaseolina, living. With the last in deep water. Astarte compressa, dead. A few valves of the smooth variety, found by Mr. Jeffreys in the Turbot-bank sand. Tellina pygmea, dead. Valves united; from the Turbot-bank sand, in Mr. Hyndman’s cabinet. Solecurtus candidus, dead. In the Turbot-bank sand. Sphenia Binghami, dead. Not uncommon in pieces of rolled chalk, and among the roots of Laminaria digitata by Mr. Grainger. Mr. Jeffreys doubts its having the power of burrowing or excavating. See Mr. Jeffreys’ “ Gleanings” in the ‘ Annals of Natural History ’ for Sept. 1859. Mya truncata. A young living specimen was brought up by the dredge from 80 fathoms on stony ground ; its usual habitat being low-water mark in mud. Saxicava arctica, living. Not uncommon, moored in cavities or crevices of stones and shells. Mr. Jeffreys considers it to be merely a variety of S. rugosa, differing in habitat. The latter, when enclosed in stone, loses the sharp keel and teeth of S. arctica, and is more rugged in appearance. Pholadidea papyracea, living. At a depth of 80 fathoms North of the Maidens, in small pieces of soft sandstone. The smaller specimens want the cup-shaped appendage, whether the effect of insufficient space or immature growth. An examination of these smaller specimens affords means of correcting an error in the first list of 1857. The so-called Pholas striata, being identical with these, is therefore to be expunged. Cynthia limacina, living. On stones and shells from deep water. Balanus tulipa alba (Hameri of Darwin) is not uncommon, living in the deep water. Balanus ? Of another species, not yet determined, a single dead specimen was found in 80 fathoms. Spheenotrochus Wrightii. A few dead specimens were found in the Turbot-bank sand by Mr. Hyndman in 1852, and subsequently by Mr. Waller. Dr. Perceval Wright, having seen these specimens in Mr. Hyndman’s collections, received permission to hand them over to Mr. Gosse, who has described and figured them in the ‘ Dublin Natural His- tory Review’ for April 1859. Sagartia coccinea. A sea anemone appearing to be this species is not unfrequent on stones and shells from deep water. Appendicularia flagellum. On the 7th of June, 1859, a bright calm day, this curious and interesting animal was seen in great abundance floating through the water at the northern entrance of Belfast Bay. It has not hitherto been recorded as Irish; but has been fully described by Professor Huxley in the ‘ Microscopic Journal,’ vol. iv. Sagitta bipunctata. Several specimens were taken in the towing net along with the former. Dr. Wyville Thomson had discovered it a short time previously in Strangford Lough. Not hitherto recorded as Irish ?. It has been described by Dr. Busk in the ‘ Micro- scopic Journal,’ vol. iv. Tlippolyte spinus. In the deep water off the Maidens: determined by Dr. Kinahan. A Northern species, inhabiting the seas of Iceland and Greenland. New to the Irish list. Acanthonotus testudo. Taken with the last. A pleistocene bed of stratified gravel was observed on the side of the road between Larne and Glenarm, and was examined by Mr. Jeffreys and Mr. Hyndman. It was found to contain several species of shells, corresponding with those from a bed at the Belfast Water Works, recorded in Portlock’s Report on the Geology of Londonderry. The following is a List of the species obtained, which will no doubt be augmented on further investigation :— Pholas crispata, fragments. Astarte elliptica. Natica clausa (nana Moller). Tellina solidula. Mytilus edulis, fragments. Buccinumundulatum(Moller). —— calcarea (Moller). Leda oblonga. Trophon clathratus. Mactra subtruncata. Hypothyris psittacea. Mangelia turricula. Astarte compressa, var. glo- Turritella polaris (Moller). | —— Pingelii (Méller). bosa. Natica Montagui. Balanus tulipa alba. ON STEAM NAVIGATION AT HULL. 119 of this number, about one-half are found living on the coast, the other half belong to extinct species. The existence of this bed of gravel with its fossils may hereafter serve to throw some light on the question of the presence of so many northern forms of shells on the Turbot Bank. As yet there is no evidence to forbid the con- clusion that all such forms may be found alive in the sea not far distant. A large proportion of those known to be living is found scattered very sparingly ; whilst others, whose existence in the living state admits of no doubt, have not yet been discovered in their haunts. Many species may be living close at hand in situations where the rocky nature of the ground, and the strength of the currents preclude the possibility of the dredge ever reaching them. One interesting fact may be noticed connected with the distribution of animal life ;—that there are several species, viz. three Nezras, two Astartes, and some others, existing in the Clyde, immediately opposite the deep-sea region north of the Maidens, where none of these species have been disco- vered ; whilst in the latter locality, Argiope, Terebratula capsula, and Phola- didea, with perhaps others, are found living and not known to exist in the former locality. The region of the Clyde and that of the Maidens, though separated by a narrow sea, exhibit well-marked and distinctive peculiarities in their respective Faunas. The Committee consider that their labours, under the liberal assistance of the British Association, have now come to a close, but much yet remains to be done to complete the List; still they hope that individuals may be found willing to continue the investigations, so as to carry out the wish expressed by Dr. Perceval Wright in his Report for 1858, that the results of the labours of the several dredging Committees may in a short time be united to form a complete Irish Marine Fauna. Continuation of Report of the Progress of Steam Navigation at Hull. By James Otpuan, Esgq., Hull, M1.C.E. In continuation of my Report on the Progress of Steam Navigation as con- nected with the Port of Hull, I have to observe that, during the last two years, no very great change has taken place in the number of steamers, although I shall have to state some interesting facts occurring during that time. For generations past, Hull has been noted for its Greenland and Davis Straits Fishery, and for many years this constituted the chief feature of the port; and at one time upwards of sixty large ships were sent out with crews varying from thirty to forty men each, and representing a capital of all that concerned the trade of about £700,000 sterling. In 1818 Hull sent out to the fishery sixty-three ships which brought home 5817 tons of oil, and in 1820 sixty ships were sent out and returned with 7782 tons of oil, exclusive of whalebone. In this year (1820) the total number of ships at the fisheries from England and Scotland amounted to 156, and the entire weight of oil obtained was 18,725 tons, and of whalebone 902 tons. Owing, however, to the introduction of coal-gas for the lighting of streets and buildings, and large importations of oils for manufacturing purposes from the Mediterranean and other places, together with the scareity and dif- ficulty of taking the whales, fish-oil became in a great measure superseded, and consequently the fishery nearly abandoned, and an enormous amount of property, once of so much value, almost entirely lost. Within the last two or 120 REPORT— 1859. three years, steam has been put into successful requisition to aid the daunt- less and hardy mariner in the pursuit of this hazardous calling, and now we have several screw steam-ships employed; and although some of them are fitted with comparatively small power, they have proved to be possessed of great advantage in the service, and in some instances satisfactorily to the owners. We have had two descriptions of steam-vessels employed in the fishery :-— the first, the old wooden sailing ships which had been engaged in the service for some years, but which were afterwards fitted with screw machinery and auxiliary steam power ; the second, iron-built ordinary screw steam-vessels, but which proved, I believe, almost a total failure; the material of which they were built, and the want of strength for such a purpose, proving them altogether unfit to contend with the severity of the climate and rough en- counters with the burgs and fields of ice, some becoming total wrecks, while others returned bruised and rent, and with difficulty were kept from sinking. A question here arises, how far iron ships are calculated to bear the severe frosts of high latitudes ? and whether wooden-built vessels, with all their defects, are not the best adapted for encountering such a climate? The screw steam- ship which was first sent from Hull or any other place to the fishery as an experiment, was the ‘Diana,’ timber-built, 355 tons and 40 horse-power, high pressure, the property of Messrs. Brown, Atkinson and Co., of Hull. This vessel had been some time engaged in the fishery as a sailing ship; but her spirited owners, thinking an important advantage could be gained, de- termined upon the adoption of steam power, and at once had the ‘ Diana’ fitted for the spring of 1857, by Messrs. C. and W. Earle, who put in the engines and made the screw to lift out in case of need. The experiment fully answering their expectations, Messrs. Brown, Atkinson and Co. bought the ‘ Chase,’ a fine American-built ship of immense strength, and of 558 tons. She was fitted by Messrs. Martin, Samuelson and Co., with condensing engines of 80 horse-power, and despatched to the fishery in the early part of 1858, and with good results. By the application of steam, ships in this service can now make a voyage, first to Greenland, and afterwards to the Davis Straits. In the commencement of this year several ordinary iron screw steamers were despatched to Greenland, viz. the ‘Corkscrew,’ ‘ Gertrude,’ ‘ Emme- line,’ and ‘Labuan ;’ the latter only of this class, which is the property of Messrs. Bailey and Leetham, had any success, but in consequence of her great strength and peculiar form, succeeded in a tolerable way ; the others were much damaged, and, as I have already remarked, returned in bad con- dition. The ‘Labuan’ is 584 tons burthen, and 80 horse-power. The next point of interest connected with the steam-ships of the Port of Hull refers to alterations made in some of the vessels. The ‘Emerald Isle,’ a paddle timber-built ship of 1835, the property of Messrs. Gee and Co., origi- nally 135-8; long, was lengthened 35 feet, with a gain of 14 inches draught of water, and an increased capacity for 100 tons dead weight. The ‘ Sultana,’ iron screw steam-ship of 1855, the property of the same house, originally 150 feet, was lengthened 30 feet, with a gain of 10 inches draught of water, and an increased capacity of about 100 tons. It is interesting to observe that in both cases we have no diminution of speed through the water, and that both vessels are improved as sea-boats. Daily experience teaches the advantage gained, in almost every point of view, by ships of great compara- tive length. The iron steam-ship ‘Lion’ of Hull, formerly a paddle-boat 249 feet long, but now converted into a screw steamer by her owners, Messrs. Brown- ON STEAM NAVIGATION AT HULL. Vor low, Lumsden and Co., under the direction of Mr. Anderson their engineer, exhibits the great advantage gained by the alteration. Her register tonnage is 690, and the total tonnage 1014. She was formerly fitted with steeple engines of 350 horse-power, and had four boilers, two before and two abaft the engines; but these were substituted by direct action engines of 150 horse-power, and two of her old boilers replaced, and by this alteration a clear length of hold in midships of 23 feet is gained. She required before the conversion 650 tons of coals for a Petersburg voyage, and consumed 30 to 40 ewt. per hour, but now 350 tons for the voyage, and a consumption of 20 ewt. per hour. By the change of machinery about 130 tons of dead weight is removed from the ship, and she is now able to carry 400 tons more cargo. Her speed is also improved considerably ; for before the alteration, when drawing on an average about 14 feet, the rate was 6} knots; but since the change, when drawing even more water, they can steam 8 knots. Thus throughout a saving almost in all the departments of the ship, and other ad. vantages have been effected in this important change. During the last two years many fine steam-ships have been built in Hull, and others are in process of building for English and foreign service, by Messrs. Brownlow, Lumsden and Co., Messrs. C. and W. Earle, and Messrs. Martin, Samuelson and Co. The last-named firm are making rapid progress in the building of two large iron paddle steam-ships, for the Atlantic Royal Mail Steam Navigation Com- pany, of the following dimensions, power, &c.:— feet Length between the perpendiculars........ 360 Bean; moulded. 2.22 .cccsecee sees ees OO epee ee i: Bids neg tise orn As pete Tonnage, builders’ measure.........--.+- 2860 Nominal horse-power ............ sean 800 These ships are to have three decks, and to be fitted fore and aft for pas- sengers. Speed through the water 20 miles per hour. They will be of im- mense strength, and their build and form such as to ensure their becoming fine sea-boats. Since the Meeting of the British Association at Dublin, considerable ad- vance has been made in London and other ports in the application of super- heated steam, and I believe with great success and satisfaction in the results. Hull, however, is acting on the motto Festina lente, and before taking a de- cided step in this important discovery, is anxious to see and adopt the best mode of the application of the principle, being assured that, in every onward move- ment, it is better to ‘‘ make no more haste than good speed.” Some attention has been paid to the consumption of smoke in the furnaces of our steam- 122 REPORT—1859. vessels, and with a considerable amount of success. I may here mention the mode of Mr. Ralph Peacock, of New Holland, Hull, for which he has taken out a patent; it consists, as shown by the plan (No. 1), of a double furnace- door, the chamber or space between the inner and outer surfaces being 5 to 6 inches in width. The inner plate is perforated very full of small holes ; and in the outer plate a revolving ventilator is inserted, which is on the principle of that invented by Dr. Hale, to supply close places with fresh air. The apparatus is in use on board the ‘ Helen Macgregor,’ one of Messrs. Gee and Company’s large sea-going steam-ships, and has given very general satisfaction ; for by the report of the Chief Engineer, Mr. M‘Andrew, a saving of fuel is effected, and the steam better sustained. Another great ad- vantage, as reported by the Master, Captain Knowles, derived from this in- vention, is that in running before the wind, they are never now annoyed and endangered by a dense cloud of smoke in the direction of the ship’s course, which, particularly at night time, creates so much risk of collision. This ap- paratus is also in use on board several other steamers, viz. the ‘ Yarborough’ and ‘Grimsby,’ belonging to the Anglo-French Company, the ‘ Alert’ of Hull, and also a number of river steam-boats. ~ I have great pleasure also in noticing an improvement introduced on board the ‘ Queen of Scotland,’ another ship belonging to Messrs. Gee and Co., for the same object, by the Chief Engineer, Mr. Smith, and having furnaces of ample capacity, answering the purpose in a most satisfactory manner. Mr. Smith’s mode consists simply in keeping a few inches of the front ends of the bars quite clear and clean from side to side of each furnace ; thus admitting at the right place a sufficient amount of air. The report of the Master, Captain Foster, is very satisfactory. I have witnessed also the effect of this mode in the furnaces of stationary boilers with perfect results, I have now to refer to the application of Silver's Marine Governor (see Plan No. 2), as applied by Mr. John Hamilton of Glasgow. Several of these ingenious and efficient instruments are now in use on board steam-ships in the Port of Hull, giving the highest satisfaction. They are so sensitive in their action, that the slightest pitching motion is at once indicated, and the steam admitted or excluded as the case may be, By the use of this governor, the full power of the engines is in immediate and constant requisition, producing the effect of saving of time, saving of fuel, and preventing of accidents by what is termed racing, and otherwise. The ordinary mode in the absence of the governor, is for the engineer, in stormy weather and heavy seas, con- tinually to stand at the throttle valves, or to save himself this trouble, to throttle the engines, and thereby, when the full power of the engines is most required, it is frequently reduced to one-half or less, and consequently there is occasioned a loss of time on the voyage, and a risk of falling on to a lee shore. The following is a brief statement of the tonnage, &c. of steam-vessels be- longing to, or trading from, the Port of Hull at the present time :— Ist. Sea-going steamers belonging to the Port, 22,290 tons register ; horse- power, 5524. 2nd. River steamers belonging to the Port, 1050 tons register ; horse- power, 450. 3rd. Sea-going steamers trading to Hull, but belonging to other ports; and although many changes have taken place remaining much the same; as shown in my last Report, viz. about 21,200 tons register ; horse-power, 5300. 4th. River steamers trading to Hull, but belonging to other places, 2450 ° tons register ; horse-power, 1200. The number and tonnage of sea-going steam. vessels belonging to Hull have increased since my last Report. The river steamers belongirg to the Port re- ON STEAM NAVIGATION AT HULL. 123 main nearly the same ; this is also the case with sea-going and river boats be- longing to other places, but trading to Hull. SS ZHAN Silver’s Patent Marine and Stationary Engine Governors. Constructed by John Hamilton, Engineer, Glasgow. The Engraving represents the Momentum Wheel Governor or “ Nautical Regulator,” as it is usually placed in the Engine-room of a Steam-Ship. It consists of a momentum wheel, A, fixed on the boss of a pinion, B, which works loosely on the spindle, C, and gears into the two-toothed sectors, D D. These two sectors being supported on a crosshead, E, made fast to and carried with the spindle, C, work in opposite directions on the pinion, B; and, as they are linked by the rods, F F, to the sliding collar, G, which receives and works the forked lever, H, communicate motion to the throttle valve. M Mare vanes, and N is a spiral spring, both of which are adjustable. The action of the above Instrument is as follows :—When the spindle of the Governor or “Nautical Regulator ” is turned by the engine to which it is attached, the two-toothed sec- tors, which are carried on the fixed crosshead, being geared into the pinion on the momentum wheel, have the tendency to turn round on this pinion ; but as they are linked to the sliding collar, they necessarily pull inwards this collar, and so compress the spiral spring; and this spring, reacting on the collar, and consequently on the toothed sectors, serves to turn round the momentum wheel, while the vanes on the momentum wheel balance the action of this spring by the resistance the atmosphere offers to their progress through it. As the leverage action of the toothed sectors upon the momentum wheel pinion increases, as the spring be- comes distended, and vice versd, it will be seen that the reaction of the spring in propelling the momentum wheel will at all times be uniform, and as much only is required as will carry round the momentum wheel with its vanes at its proper speed, and overcome the friction of working the throttle valve, and throttle valve connexions. When the momentum wheel is in motion, it will rotate with the engine to which it is attached, at a velocity proportioned to that at which it is fixed by the connecting gear; and while the engine from the usual causes may attempt to vary this velocity, it cannot affect the momentum wheel, but leaves it free to act upon the sliding collar, and consequently upon the throttle valve—at one time closing the throttle valve by its action in resisting any increase of velocity, and at another time opening the throttle valve by its action in resisting any decrease of velocity on the part of the engine. It will now be evident that the power of such a Governor or Regulator must be very great indeed, having for its agent amomentum wheel which may be increased to any dimensions ; and from the powerful resisting tendency of such wheel, it necessarily follows that its sensitiveness of action must also be very great, and in exact proportion to the tendency of the engine to vary its speed; and the engine itself being the direct prime mover of the throttle valve, it also follows that the inert power of the momentum wheel increases its resistance exactly in proportion to the rapidity with which the engine varies its speed. Hence a momentum wheel of 2 feet 8 inches diameter, and 2 inches periphery, running at a speed of 180 revolutions per minute, is found to be sufficient to work with promptness and ease the largest throttle valve, and to equal the power of several men. Unlike the ordinary forms of Governors, it is entirely unaffected by changes of position, and therefore perfectly adapted for Marine and Portable, as well as Stationary Steam-Engines. 124 REPORT—1859. Mercantile Steam Transport Economy as affected by the Consumption of Coals. By CuHarues ATHERTON, Chief Engineer, Royal Dock- yard, Woolwich. Pustic usefulness, as dependent upon science, being the great object for which the “British Association for the Advancement of Science” was originated, and has now been signally upheld for twenty-nine years, a period remarkable for the progress that has been made in the utilization of the powers of nature, to such an extent that the international condition of the globe is now being revolutionized by the progressive practical utilization of elements which heretofore were regarded merely as phenomena of nature, viz. Steam and Electricity ; in which revolution the application of steam to the purposes of navigation has played so conspicuous a part, that now, in proportion as steam may be effectively employed in the pursuits of commerce and of war, it is acknowledged that even nations will rise or fall ; seeing, moreover, that at no period in the history of steam navigation has so great a step been made in its practical development as has recently been realized by the fearless intro- duction, in marine engineering, of the long known but neglected effects of increased pressure, superheating, and expansion ; the recognition and appli- cation of which principles have now, at length, been attended with such effect in marine engineering, that the consumption of fuel with reference to power is now known to be practically reducible to less than cne-half of the ordinary consumption of coal on board ship ;—seeing also that mercantile enterprise, setting no limit to speculative investment, has in these days emancipated mechanical intellect from the restrictions by which ideas as respects magni- tude have hitherto been bound ;—under such circumstances I cannot doubt that any effort to popularise a knowledge of the practical utilization of steam, with reference to the consumption of fuel, though advanced with no pretensions to science, beyond that which may be awarded to originality and labour in the application of calculations to develope useful results, will be favourably received, more especially as the paper which I now beg to present is in continuation and conclusion of an inquiry, which has already, in part, on two occasions been favourably entertained by this Association, and honoured with a place in its published records. The former papers to which ! allude are,—1st, “ Mercantile Steam Transport Economy, with reference to Speed,” vol. for 1856, p. 423; 2nd, “Mercantile Steam Transport Economy, with reference to the Magnitude of Ships, and their Proportions of Build,” vol. for 1857, p. 112. And I now purpose to bring this inquiry to its con- clusion by the following paper on— Mercantile Steam Transport Economy, as affected by the Consumption of Coals.—My purpose, and the drift of my remarks will probably be the more readily understood by my at once adducing the following Tables C and D, and the diagram E, in continuation of the Tables A and B, which are pub- lished in the Volume of Reports for the year 1857, pp. 116 and 119, observing with reference to these Tables C and D, that the rate of consump- tion of coal on which the calculations are based, viz. 23 lbs. per indicated horse-power per hour, has been practically realized on continuous sea service, although the ordinary consumption of steam-ships in the Royal Navy, as well as in the best vessels of the most celebrated steam-shipping companies, is, I believe, at the present time fully 50 per cent. in excess of that amount; and I may say, that in steam shipping generally, the consumption of coals per- knot of distance, with respect to displacement and speed, is double the con- sumption which these Tables, based as they are on an example of existing practice, show to be now practically realizable. ON MERCANTILE STEAM TRANSPORT ECONOMY. 125 The Tables now adduced are as follow :— Taste C.—Calculated for the Speed of 10 knots per hour, and showing the mutual relations of Displacement, Power, and the Consumption of Coal, per Day, Hour, and Knot, the Coefficients of Dynamic performance, deduced from the Formula Ee nd. h. p. of fuel at the rate of 23 lbs. per Ind. h. p. per hour. , being assumed to be 250, and the consumption ee ee DIsPLACEMENT. or els Per Hour. Le Knot. at the unit 100,000 lbs. 1ft. per min. Indicated H.P.taken at the unit 33,000 Ibs. 1ft, per min. =| g 2 fe ms i 2 f 5 o A Tas_e C. Calculated for the Speed of 10 knots per hour. EPORT—1859 R 126 ‘LL \ " BLT 8-87 3 LST H i LP 8.F1 : . 0.64 €.88 i 8-81 9.84 ®.9E L-61 P68 : Z.11 F 4 6-63 S.OT A i G.9S $.96 16.6 1.67 L-¥Z . 19.8 6.90 €.43 10.8 StL . 8.60 .0Z : 68.4 SEI 6.68 9.81 i 19.9 O6T i V-S& €.9T 18.9 901 €.1€ 8ST 19.9 . GOL B.0E 6ST LP. ¢.86 6.62 9-FT | 998 16-9 6-76 L-82 Speeds of ive ynamic Performance tof D len ions of Displacement, Power, and ssumed to be 250, and the Con- and per Knot, for the respect 10, 15, 20, and 25 Knots per Hour :—the Coeffic = OFT | ge 90.9 LI6 0.12 = G.El | Lge $8.P G18 8.92 a) 821 | 12e £9.P 6.8 L-¥G = @ZL | 908 WAZ €.64 G.8B é. 9.11 | 062 8L-P BSL @.1% a ee 6.01 | 842 ; 76.8 6.04 0.26 wehize G.0L | 492 ' OL 9.99 1.61 > 99.6 | 68 &P-8 i 8.19 P81 = 8.8 | 186 61-2 ; P-Lg 0-LT $3.8 906 86.4 $.E9 8.9T 79.4 | Té6L GL.S +o ! 9.F1 00.2 SLT TS.2 G. P-EL 82.9 LST 5 16-3 8.07 L.21 99.9 | 68 : 0:3 T.98 : L010 "yg | 349 ; "4A “suo, “suo, 'youy Iq}‘mMoy id’ 8 ed H f | c a ‘yous Iq|‘moy Iq|*heq 19g ‘uoy, 10d TOCA CAG Jo 4oaz “s[eog *s[e0p F120) “s[eop Juowmovydsiq, t Tasie D.—Showing the Mutual Relat Coals consumed per Day, per Hour, dIqnd gE qe ‘suOoy, ‘SJOUYL 92 "s]0US 0% ‘S]OUY ST *s}OUS, OL sumption of Coals at the rate of 24 Ibs. per indicated horse-power per hour. deduced from the Formula ON MERCANTILE STEAM TRANSPORT ECONOMY. 127 Dracram E, showing approximately the Nautical Mileage Consumption of Fuel, for vessels from “1000 tons displacement, up to 25,000 tons, rig 3 efficients of Dynamic Performance deduced from the Formula Ind. h. p. being assumed to be 250, and the Consumption of Coals being assumed to be at the rate of 24 Ibs. per Ind. h. p. per hour. r Hy HH | 23 ECHO te th 3 aC de Hore Epa B= SET Ar Amend a al / as YK g [| Vis7’ EEE eo aaa ca sarees BEES HAA ly guile tT | | Vy perl ViPZaraR Se WALL Saal HE 9 10 11 12 13 14 165 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Z AE PCC Dishtadabhepsnhe TEEPE TT 5,000 10,000 16,000 20,000 25,000 Oat. a3 45 6 7-8 _With reference to the foregoing Table C, showing the mutual relations of displacement, power, and the consumption of coals per day, per hour, and per knot, for vessels of a gradation of sizes, from 250 tons displacement up to 25, Ot tons, the coefficient of dynamic performance, deduced from the formula meh a being assumed tobe250, and the consumption of coals being assumed to be at the rate of 23 lbs. per indicated h. p. per hour, on these data, the 128 REPORT—1859. coefficient of dynamic economy with reference to coals deduced from the 3 formula ewts.) becomes 11210. It will be observed that in Table C the tabulated sizes of ships, as deter- mined by their respective load displacements, increase progressively from 250 tons displacement up to 25,000 tons, showing under assumed conditions, which, however, are justified by now realized advancement in ship and engine construction, the mutual relations of displacement and coals cal- culated for the speed of 10 knots per hour as most convenient for a standard of reference. The intended practical use of this Table C is to facilitate mercantile investigation into the dynamic merits of steam-ships as locomotive implements of burden by comparing their actual consumption of fuel with the calculated consumption of the ship of corresponding size and speed as recorded in this tabulated standard of comparison, whence the constructive merit of ships, as respects their working economy of fuel, on which the cost of freight so much depends, may be relatively ascertained. For example, a certain ship of 800 tons mean displacement attains the speed of 8°8 knots per hour, with a consumption of coals certainly not exceeding 4°3 ecwt. per hour, or *49 ewt. per nautical mile or knot; which (as the consumption of coals per knot varies cateris paribus as the square of the speed) is equivalent to ‘63 ewt. per knot at the speed of 10 knots per hour. Now by referring to Table C, we find that on the assumed data therein referred to, the standard ship of 800 tons displacement, steaming at 10 knots per hour, would consume °77 ewt. of coal per knot. Hence, therefore, it appears that the ship referred to in this instance is superior to the tabulated standard in the proportion of -77 to 63, that is, in the proportion of 122 to 100, the superiority with reference to the consumption of coals per knot being 22 per cent. Again, a certain ship of 3500 tons mean sea displacement makes a voyage at the average speed of 12°88 knots per hour, consuming 83 ewt. of coal per hour, or 6°44 ewt. per knot, which, by the law of dynamics above quoted, is equivalent to 3°88 cwt. per knot at the speed of 10 knots per hour; but by referring to the Table of comparison C, we find that the standard ship of 3500 tons displacement, steaming at 10 knots per hour, would consume only 2:06 cwt. of coal per knot. Hence, therefore, it appears that the ship re- ferred to in this instance is 7zferior to the tabulated standard ship in the pro- portion of 2:06 to 3°88, that is, in the proportion of 53 to 100, the inferiority with reference to the consumption of coals being 47 per cent. Thus, by reference to this tabulated standard of comparison (C), we have the means of readily deducing the exact per-centage by which ships, respects the dynamic duty performed with reference to the consumption of coals, differ from each other. I need not dwell on the importance of this consideration as affecting the commercial value of ships for sale or charter. With reference to Table D, showing the mutual relations of displacement, power, and coals consumed per day, per hour, and per knot for the respective speeds of 10, 15, 20, and 25 knots per hour, the object of this Table is to show the extent to which the required engine-power, and the nautical mileage consumption of coals are dependent on the rate of speed, thereby facilitating the adaptation of ships as respects their size and power to the service that may be required of them. For example, by referring to Table D, we observe that a ship of 5000 tons , displacement, steaming at 10 knots per hour, requires 1170 indicated h. p., and consumes 2°61 ewt. of coal per knot; but to steam 15 knots per hour, the same vessel would require 3947 ind. h. p., and the consumption of coals, (w being the consumption of coals per hour expressed in ON MERCANTILE STEAM TRANSPORT ECONOMY. 129 would be 5:87 ewt. per knot; hence it appears that to increase the speed from 10 to 15 knots per hour, the power requires to be increased upwards of three times, and the consumption of coals per knot is more than doubled. Again, let it be supposed that the weight of the hull of a ship of 5000 tons displacement fitted for sea amounts to 40 per cent. of the displacement, or 2000 tons, and suppose the weight of the engines and boilers to be one ton for each 10 indicated h. p., the vessel requiring, as shown by Table D, 1170, indicated h. p. to attain the speed of 10 knots per hour, with a consumption of coals at the rate of 2°61 cwt. per knot; then on these data, the engines, to attain the speed of 10 knots per hour, would weigh 117 tons, and the weight of coals for a passage of, say 12,000 nautical miles, would be 12,000 x 261= 31,320 ewt., or 1566 tons weight, making together for hull, engines and coals 2000+117+1566=3683, and consequently the displacement avail- able for cargo would be 5000—3683=1317 tons weight. But if it be purposed that the steaming speed shall be at the rate of 15 knots per hour, the required power, as appears by Table D, will be 3947 ind. h. p., con- sequently the weight of the engines will be 395 tons, and the maximum dis- placement available for coals will be 5000—2395=2605 tons weight, or 52,100 ewt., which, at the tabulated rate of consumption, 5°87 cwt. per knot, would be sufficient only for a passage of 8876 nautical miles, and this to the utter exclusion of all goods cargo, showing that the ship is inadequate for steaming 12,000 nautical miles at the required speed of 15 knots per hour, though the same ship, if duly fitted with engine-power for steaming at 10 knots per hour, would perform the whole passage of 12,000 nautical miles without re-coaling at any intermediate station, and carry 1317 tons of re- munerating goods cargo. These few examples will, it is hoped, sufficiently illustrate the application and use of Tables C and D in facilitating mercantile inquiry into the capa- bilities of steam-ships with reference to the all-important question of con- sumption of coals; but in order still further to facilitate calculations on this subject, the diagram E has been prepared, whence, simply by inspection, the consumption of coals per knot, at any rate of speed, may be approximately ascertained for vessels of improved modern construction up to 25,000 tons, the data on which this diagram has been calculated being the same as that on which Tables C and D are based. The use and application of this Diagram E is evident ; it brings theTables under ocular review, and generalizes their application. It is given as an example of a system that admits of being more fully and elaborately deve- loped for the purposes of mercantile tabular reference, as is now being done for publication. Having thus explained the use and application of Tables C and D and the Diagram E, it will be perceived that the task which I have undertaken on this occasion is to show palpably by comparison with these tabular statements, based on data within the limits of already realized results, taken as a standard, what is the relative character of steam-ships as respects their locomotive or dynamic capabilities, with reference to the economic performance of mercantile trans- portservice, so far as dependent on the consumption of fuel; thus affording an exposition whereby parties interested in steam-shipping, either as owners or directors, or agents, or as the charterers of shipping for government or for private service, though unacquainted with the details of marine engineering as a science, may be enabled to arrive at some definite appreciation of the eapabilities that may be expected of steamers; that is, the weight of cargo they will carry, and the length of passage capable of being performed at any definite speed ; for, as before observed, the dead weight of cargo that a ship 1859. K 130 REPORT-~1859. will carry is equal to the tons’ weight of water displaced between the light and load water-lines of the ship, less the weight of coals and stores required for the voyage, and which for long voyages commonly amount to four times the weight of cargo chargeable as freight, and it constitutes the limitation of distance which the ship is able to run under steam at a given speed. This inquiry is therefore essential to a due appreciation of the economic conse- quences which are involved in progressive variations of steam-ship speed, especially as respects the high rates of speed, which are occasionally professed, but which are seldom realized, simply because there has been no recognized exposition, whereby such pretensions may be judged of with reference to the required consumption of fuel. In short, regarding this matter as a public cause, affecting as it does the pecuniary interest of the public to the extent of millions sterling per annum, my object is to promulgate, through the medium of the notoriety which every inquiry obtains upon its being brought before the “British Association for the Advancement of Science,” a Mercan- tile Steam-ship Expositor, by reference to which as a standard of comparison the good or bad qualities of steam-shipping may be determined ; and this surely is a public cause, for by the operation of the scrutiny which such a system of comparative exposition may be expected to inaugurate and popu- larize, steamers will soon become marketable, with reference, in great measure, to their capabilities for economic transport service, at the speed that may be required; under the influence of this scrutiny all bad types of form and vicious adaptation of mechanical system will be eradicated ; incompetency in steam-ship management will become gradually eliminated, and the mer- cantile transport service of the country being then performed exclusively by good, well-appointed, and well-managed ships, would be performed at a minimum of cost to the shipping interests, and consequently to the best advantage for the interests of the public. Hitherto the dynamic charac- ter of steam-ships has been a mechanical problem enveloped in undefined and even delusive terms of shipping and engineering art; consequently its determination has not been based on any recognized principles of caleu- lation. Hence the dynamical character of shipping has been a mystery — a matter of mere assertion on the one hand, and of credulity on the other. But mystery being unveiled, commercial vision will be opened, and compe- tition, in shipping as in any other well-understood and open field of public enterprise, will ensure the mercantile transport service of the country being performed to the best advantage, and it will gradually establish and preserve the just equilibrium of freight charges as between the carriers and consumers of all sea-borne productions. Report on the present state of Celestial Photography in England. By WaRREN DE LA Rue, PA.D., F-R.S., Sec. R.A.S., §e, In bringing before the Association the present Report it will be only neces- sary, after referring briefly to the labours of others, to confine myself to an account of my personal experience; for, although other observers have occasionally made experiments in Celestial Photography, there has not been any systematic pursuit of this branch of Astronomy in England, except in ~ my Observatory, and under my immediate superintendence in the Kew Observatory. ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 131 Part 1. Historical Outline. The late Professor Bond of Cambridge, in conjunction with Messrs. Whipple and Black of Boston in the United States, was the first to make a photographic picture of any celestial body. By placing a daguerreotype plate in the focus of the great refractor of the Harvard Observatory, of 15 inches aperture, he obtained a daguerreotype of our satellite. This was, I believe, about the year 1850, for 1 remember seeing one of these pictures in the Exhibition of 1851, and some were exhibited at the meeting of the Royal Astronomical Society in May 1851. The experiments were discon- tinued after a time in consequence of irregularities in the going of the clock-work driver, and were not resumed again till 1857, when new clock machinery was attached to the telescope*. At the latter end of 1852, I made some successful positive lunar photo- graphs in from ten to thirty seconds on a collodion film, by means of an equatorially mounted reflecting telescope of 13 inches aperture, and 10 feet focal length, made in my workshop, the optical portion with my own hands ; and I believe I was the first to use the then recently discovered collodion in celestial photography}. In taking these early photographs, I was assisted by my friend Mr. Thornthwaite, who was familiar with the employment of that new medium}. At that period, I had not applied any mechanical driving motion to the telescope, so that I was constrained to contrive some other means of following the moon’s apparent motion ; this was accomplished by hand; in the first instance, by keeping a lunar crater always on the wire of the finder by means of the ordinary hand-gear of the telescope, but after- wards by means of a sliding frame fixed in the eye-piece holder, the motion of the slide being adjustable to suit the apparent motion of our satellite ; the pictorial image of the moon could be seen through the collodion film, and could be rendered immoveable in relation to the collodion plate, by causing one of the craters to remain always in apparent contact with a broad wire placed in the focus of a compound microscope, affixed at the back of the little camera box, which held the plate. Although these photographs were taken under the disadvantage referred to, namely, the want of an automatic driving motion, excellent results were nevertheless obtained, which proved how perfectly the hand may be made to obey the eye. I could not take photographs of the moon in this way alone, but required always the aid of an experienced coadjutor, willing to lose the greater portion of a night's rest, often to be disappointed by failures resulting from the state of the weather, and numberless impediments sufficient to damp the ardour of the most enthusiastic. For some months Mr. Thornthwaite was so kind as to continue his valuable aid, and several good positive pictures were obtained ; but the difficulties we had to encounter were so great that it was at last resolved to discontinue the experiments until such time as a driving motion could be applied to the telescope. This was done early in 1857 §, since which period I have unremittingly followed up the subject of celestial photography when- ever my occupations and the state of the atmosphere have permitted me to * Astronomische Nachrichten, No. 1105, p. 1. + These pictures were exhibited in the early part of 1853 at the Royal Astronomical Society. $ Mr. Archer applied the solution of gun cotton (collodion) to photography in 1851, and suggested pyrogallic acid for developing the latent image. § Monthly Notices of the Roy. Ast. Soc. vol. xviii. p. 16. K 2 © 132 REPORT—1859, do so. With what result, the Association will have an opportunity of judging by the examples exhibited*. Professor Phillips, aided by Mr. Bates, obtained some lunar photographs in July 1853, and communicated the results of his experience in a valuable paper at the Hull meeting of the Associationt. Mr Hartnup of Liverpool, aided by Mr. J. A. Forrest, Mr. McInnes, Mr. Crooke, and other photo- graphers, took some good pictures of the moon in 1854¢; Father Secchi, at Rome, and more recently Mr. Fry, in Mr. Howell’s observatory at Brighton, and Mr. Huggins, near London, have also produced lunar pictures : these experiments were in all cases made with refracting telescopes, corrected for the visual ray. Professor Bond, in April 1857, applied the process with promise of a fruitful future, in measuring the distance and angle of position of double stars§, and also in the determination of their magnitudes ; just pre- vious to his decease, this new application of the art appears to have engaged his attention more than lunar photography. He succeeded in obtaining pic- tures of fixed stars down to the 6—7th magnitude. The Photographic Picture compared with the Optical Image. It will render what I shall hereafter have to say more easily understood if I commence by bringing under notice what happens in applying photo- graphy to sidereal astronomy. The optical image of a fixed star, it will be remembered, is not a mathematical but an optical point, which, in conse- quence of the properties of light, is seen with the telescope as a very minute disc, surrounded by rings, which become fainter and wider apart as they enlarge, these rings being always more or less broken up, according to the state of the atmosphere. The photographic image must, therefore, be of a certain size, but it is after all a mere speck, difficult to find among other specks which are seen in the most perfect collodion film, when it is viewed with a magnifying power. : For example, let it be supposed that a telescope of sufficient aperture is turned upon a Lyre; a star conveniently situated from its great meridional altitude for photography, and moreover sufficiently brilliant to give a nearly instantaneous picture: if the telescope be steadily supported at rest, the star will, in consequence of the earth’s rotation, course along the field of the telescope, in a line parallel to the earth’s equator, and, as it produces an instantaneous picture, the image obtained is a streak, representing the path of the star. We might be led to expect, a priori, that this line, for a short distance, would appear straight; but, so far from this being the case, it is broken up and distorted, and consists of a great number of undulating points, crowded in some places, and scattered in others. This distortion arises from the disturbances in our atmosphere which cause the star to flicker. In the foregoing remarks, the telescope was supposed to be at rest; now * The photographs exhibited at the Aberdeen Meeting were the following :—Two original negatives which would bear considerable magnifying power ; two positive enlarged copies of other negatives, eight inches in diameter, which would bear still further enlargement with a lens of low power; twelve enlarged positives of the Moon in different phases, 34 inches in diameter, among which were three, showing the progress of the lunar eclipse on February 27, 1858; enlarged positive copies of Jupiter, exhibiting his belts and satellites; lastly, a photograph of Saturn and the Moon taken together at the recent occultation of that planet just after the planet had emerged from the moon’s bright limb (May 8, 1859). The last- named photograph was produced in 15 seconds ;—a remarkably rapid result for so faint an object as Saturn. The planet on this occasion was seen to be of about the same brilliancy as the Mare Crisium situated near the moon’s western limb, with which the planet could be readily, compared, from its proximity to that lunar district. T Report of Brit. Assoc. 1853, Trans. Sect. A, p. 14. t Report of Brit. Assoc. 1854, Trans. Sect. B, p. 66. § Astronomische Nachrichten, No. 1105. ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 133 let it be assumed that the telescope is mounted on an axis parallel with the earth’s axis, and provided with a driving apparatus, capable of carrying the telescope round in the direction of the star’s apparent path so equably, that, if viewed with a micrometer eye-piece, the image of the star would remain always in contact with one of the wires of the eye-piece. The photographic picture of a star, obtained by a telescope under these conditions after some seconds’ exposure, is not one single clear disc or point, but a conglomeration of points, extending over a greater or less area, according as the atmosphere has during the interval produced more or less flickering. If a mere speck, like a fixed star, acquires comparatively large dimensions on a sensitized plate in consequence of atmospheric disturbances, every optical point in an image of other celestial objects must, from the same cause, occupy a space of greater dimensions than it would if no disturbing influences existed. When the telescope is employed optically, the mind can make out the proper figure of the object, although its image dances before the eye several times in a second, and is able to select for remembrance only the states of most perfect definition; on the other hand, a photographic plate registers all the disturbances. ‘The photographic picture will conse- quently never be so perfect as the optical image with the same telescope, until we can produce photographs of celestial objects instantaneously : we are still a long way from this desirable end. Relative Advantages of Reflecting and Refracting Telescopes for Photography. With refracting telescopes, the photographie focus of a point of light occupies a larger area than with reflectors; this is especially the case with Astronomical Telescopes, because they are corrected so as to produce the best optical image, and the outstanding chemical rays are dispersed around the luminous focus*. The reflecting telescope has, therefore, considerable ad- vantage over, the refracting telescope for celestial photography, on account of all rays coming to focus in the same plane; hence, the focus having been adjusted for the luminous image, it is correct for the chemical image, and has not to be disturbed, as with a refractor. In the telescope employed by Professor Phillips, of 6} inches aperture and 11 feet focal length, the actinic focus was found to be 0°75 inch beyond the visual focus ; and in the Liverpool Equatorial of 123 feet focal length the actinic focus was 0°8 inch beyond the visual focus. With my telescope the focusing is critically effected with the aid of a magnifier, the image being received on a piece of ground glass placed temporarily in the actual slide destined to contain the sensitized plate; a second piece of ground glass fixed in a frame is put into the camera just previous to each operation, for the purpose of placing the telescope in position; but the focusing is always effected in the manner de- seribed, for the goodness of the picture depends greatly on the accuracy of this adjustment. I attribute much of my success to the employment of a re- flector, while my fellow-labourers in the same field have used refractors. Actual Process employed at the Cranford Observatory. With the view of facilitating the labours of others desirous of entering the field of photography, I will now describe, with all necessary minuteness, the process finally adopted alter many trials and failures; I would remark at the same time that it is quite impossible to give such directions as will enable another operator to ensure perfect results, as this can only be attained by perseverance, long practice, and a strong determination to overcome obstacle after obstacle as it arises,—therefore, no one need hope for * Refracting telescopes can be specially corrected for the chemical focus in the same way as Camera lenses. 134 REPORT—1859. even moderate success if he dabbles in celestial photography in a desultory manner, as with an amusement to be taken up and laid aside. . In order to prosecute celestial photography successfully, there must be, in close contiguity with the telescope, a Photographic Room, abundantly supplied with both common and rain water. The water-taps should pro- ject over a sink, so as to reach about a foot from the wall. The rain water is conveniently kept in and filtered by an ordinary stone-ware filter. The photographic room may be lighted generally by means of an ordinary Argand reading lamp, over the shade of which hangs a lantern-like curtain made of two thicknesses of deep-yellow calico; but the plate, during the development of the picture, must be illuminated locally by a night-light before which a yellow screen is placed. The photographic room should be furnished with a stove, burning wood or charcoal, which will keep alight for a long time, in order that its temperature may never fall much below 50° F. during the winter. In my earlier experiments, the positive process was invariably employed on account of its greater rapidity; but so many details, visible by trans- mitted light in a positive, are lost when it is afterwards viewed by reflected light, that endeavours were made to render the negative process equally rapid. After many trials, I succeeded in this; and I now never have recourse to the positive process, except for some special object. Glass used.—It is of course necessary to have the plate somewhat larger than the object to be taken ; the size used when the telescope is employed as a Newtonian is 22 inches by 34 inches. When the pictures are taken by the direct method, the plates are circular, and 23 inches in diameter. The outside diameter of the slide to contain the circular plate is 3} inches, the exact size of the cell of the diagonal mirror, so that no more light is stopped out by the plate-holder than by the smail mirror. The glass used is the “extra white patent plate,” and I have it selected as free from specks and bubbles as possible, but nevertheless I have frequently to reject about one-third of those discs which are supplied to me. Mode of Cleaning the Plate——The glass is cleaned in the ordinary way by means of tripoli powder, mixed up with three parts of spirit of wine and one of liquid ammonia, to the consistence of cream. For drying the plates I am provided with two* cloths, which, in the first instance, have been carefully washed with soda (avoiding the use of soap), and repeatedly rinsed in water. Each time after being used, these cloths are thoroughly dried, but they need not be washed for months together. For the final wiping of the plate a piece of wash-leather is employed, also carefully dried before being used. A piece of grit-stone, such as is used by mowers to sharpen scythes, must be at hand, for the purpose of grinding the edges of the glass plate and making scratches on the margin of the two surfaces, in order to cause the more perfect adherence of the collodion, The plate to be cleaned is placed on a sheet of cartridge paper, and rubbed thoroughly, first on one side, then on the other, with a piece of mew cotton- wool moistened with the tripoli mixture, above described. Itis then washed in a stream of water, the fingers being used, if necessary, to aid in removing the adhering tripoli. Holding the plate while still wet, and without touching the surface, one edge after the other is rubbed on the grit-stone; the glass imbeds itself in the friable stone, and thus the borders of the two surfaces get scratched, and the edge is ground at the same time. After the four edges have been so ground, or, if the plate be circular, the whole periphery - has been rubbed, the hands, and plate are well washed, to remove all grit, and the plate placed edgewise for a few seconds on a marble slab. With dry * It is disadvantageous to employ more cloths than are absolutely necessary. ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 135 hands, I take up the plate by the edge, being now very careful not to touch the surface with the hand, and wipe it, first with one cloth, then thoroughly dry with the second, and lastly, rub both surfaces at the same time with the dry wash-leather. I afterwards breathe on each side of the plate, to ascertain whether it is clean, wipe off the condensed moisture and place the plate in a grooved box, with the best surface turned to face a marked end of the box, so as to know on which side to pour the collodion. Proceeding in the above- described manner, I have never any failure attributable to a dirty plate, and can feel certain of obtaining four or five good pictures of the moon out of about seven plates generally used. I am usually, however, provided with one or two dozen cleaned plates, for it is desirable to have a sufficient reserve, and experience has proved that plates so cleaned may be used even after a week, if the box containing them be kept in a dry room. The Bath.—It is of the utmost importance that the nitrate of silver bath should be in the most sensitive condition ; the rapidity of the process appears to depend in a great measure on its not being in the slightest degree acid, but as nearly neutral as possible. It is almost needless to add that, for such a refined application of photography as that under consideration, the solution should be kept in glass in preference to gutta percha. The vessel must be carefully covered, to exclude dust, and, from time to time, the solution should be filtered through pure filtering paper (Swedish paper). The nitrate of silver used in the preparation of the bath is invariably fused in my own laboratory, in quantities never exceeding a drachm at one time, the requisite heat being gradually applied, and care being taken not to raise the temperature higher than is necessary to effect the fusion. The solution I employ is the ordinary one of thirty grains of nitrate of silver to the ounce of water, with a quarter of a grain of iodide of potassium. In the preparation of a bath, after the mixing of the nitrate of silver, dissolved in a small portion of the water, with the solution of iodide of potassium, it is customary to add the remaining chief bulk of water, which causes an immediate precipitation of iodide of silver, and then to filter the liquid after the lapse of half an hour. It is, however, advisable to agitate the solution from time to time, during several hours before it is filtered; for unless this be done, the bath does not become thoroughly saturated with iodide of silver, and has a tendency for some time to dissolve a portion of the iodide of silver which first forms in collodion immersed in it. I avoid adding alcohol or acetic acid to the bath, for these substances impair its sensitiveness. As, after use for a certain time, the bath becomes charged with more or less alcohol and ether, and their products of oxidation, its properties become changed, and a picture cannot be taken with it with sufficient rapidity ; when I find this to occur, I discard the bath and make a fresh one. The bath, in its most sensitive state, usually exhibits a very feeble alkaline reaction with reddened litmus paper, and if it be found to have a tendency to fog, it is corrected in this way:—A single drop of pure nitric acid is taken on the point of a glass rod, and mixed with a drachm of distilled water; with this diluted acid (1 to 60) I moisten the point of the glass rod and stir it about well in the bath, which contains about fourteen fluid ounces of solution, and make atrial. If it still fogs, the acidification is repeated ; and thus, after several trials, the fault is corrected. It is better to proceed in this manner than to rely on litmus papers as a test for neu- trality ; the object being to retain the bath in as sensitive a state as possible, the test by light is the only one to be ultimately depended on. Moist hydrated oxide of silver may be used to bring back a bath, which has become acid by use, to a neutral state, and by the subsequent careful 136 REPORT—1859. addition of dilute nitric acid it may be made to work ; but all additions of acetate of soda, carbonate of soda, or acetic acid, are quite inefficacious for correcting a bath that does not work satisfactorily. In order to obtain the extreme point of sensitiveness, the best plan on the whole is to make a new bath ; the silver being, as is well known, easily recoverable from its solutions and in part, by evaporation and crystallization, as nitrate. Collodion.—The condition of the collodion is also an all-important point, and it appears to be very capricious in its properties. It is preferable not to make the collodion oneself, but to use that prepared by makers of repute ; I usually employ Thomas’s or Hardwich’s collodion, both of which I have found to be very uniform in quality. It is desirable to sensitize frequently new batches of collodion, and to determine by experiment from time to time the gradual development and decline of their sensitiveness. Collodion should not be sensitized until after it has stood for, at least, a week after it has been purchased, and it must then be carefully poured into the mixing vessel without disturbing the sediment which always is present. It must be agitated occasionally for some hours after mixing with the sensi- tizer, before it is set aside to rest and deposit the new sediment which forms. After standing for a week, it should be carefully decanted for use, to the extent of three-fourths, into a perfectly clean glass vessel. The glass mixing vessels should invariably, previous to use a second time, be washed out, first with a mixture of equal parts of ether and alcohol, and then with water and pieces of blotting-paper, well shaken up, so as to reduce the paper to pulp; and finally, rinsed out with distilled water, and suspended in a warm place, mouth downwards, to drain and dry thoroughly. Iodide of cadmium appears, on the whole, to be the best sensitizer for collodion to be used in celestial photography: collodion, prepared with this salt, is not very active when first mixed; hence it differs from collodion prepared with iodide of potassium and iodide of ammonium in this respect, but it gradually acquires a degree of sensitiveness unsurpassed, if equalled, by collodion rendered active with the latter salts, used either alone or mixed with other salts. Collodion, mixed with iodide of potassium, acquires, it is true, great sensitiveness soon after it is prepared, but in a few days it. loses in this respect, is moreover continually changing, and is seldom available in celestial photography after standing a month or six weeks; whereas cadmium collodion will retain its qualities for several months. As fresh mixed collo- dion is certain to produce both white and dark specks in the photograph, as large or larger than the details visible in the picture with a magnifier, it will be seen that a collodion which can be kept for a long time to deposit, without losing in sensitiveness, must be the most valuable; moreover, in collodion mixed with the alkaline iodides there is always an evolution of free iodine which soon impairs the sensitiveness of the nitrate of silver bath by rendering it acid; and for these reasons I generally give the preference to cadmium collodion. Sometimes collodion exhibits a reticulated structure after the photograph has dried, which materially militates against the beauty of the picture, and prevents its being highly magnified ; it occasionally happens that this defect cannot be cured, in which case the collodion should be rejected. I have generally found, however, that this “craping” may be obviated if the collodion be diluted, more or less, with a mixture of two parts of ether and one part of alcohol when it is being sensitized, care being taken to add as much of” the solution of iodide in relation to the diluting liquids as would have to be added to an equal volume of collodion. ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 137 After using collodion for several evenings, it is well to allow it to stand for some days, and to decant about three-fourths into a fresh vessel. Before pouring the collodion on to the glass plate, the usual precaution of cleaning away with the fingers any dried collodion from the lip of the containing vessel must be attended to; moreover, each time, just in the act of pouring, a few drops should be allowed to fall to waste on the floor; by attention to these remarks, much vexation will be avoided. Exposure of the Plate in the Telescope——On taking the plate from the nitrate of silver bath, it is desirable to drain it well before it is put into the slide, first on the edge of the bath, then on white blotting-paper, shifting its position two or three times, but always keeping the same point downwards. It must be carried to the telescope as quickly as possible, and the picture developed immediately after it has been removed from it. The sensitized plate rests on angles of pure silver, let into the square plate-holder, or in the circular plate-holder within a ring of pure silver, the face resting on three prominent places. I have found that contact with wood is liable to produce stains which occasionally extend across the plate during the development. The circular plate-holder is entirely of metal, and I would recommend metal holders in preference to these of wood for celestial photography, because they are not liable to warp and become set from damp when left in the observatory. The plate-holder should be wiped with a clean cloth after each operation, and the hands also washed each time before a fresh plate is taken, on which it is intended to pour collodion. In order to subject the sensitized plate to the action of light when the telescope is used as a Newtonian, I remove a very light cover, previously placed over the mouth of the telescope, and replace it when I wish to dis- continue the action; this cover is made of black merino, stretched on a whalebone hoop and is provided with a handle of bamboo. In the direct method, I turn up or down, through an are of 90°, a little hinged trap, interposed between the great mirror and the sensitive plate. This motion is given by means of a lever fixed on a light axis, supported by the arm which holds the small camera; the axis extending beyond the edge of the telescope tube, and carrying a milled head by which it is turned. Regulation of the Time of Exposure.— A journeyman-clock, beating seconds distinctly, should be near the telescope, in order that the operator may be enabled to regulate the time of exposure, which requires great nicety with such sensitive chemicals as must be employed. The time occupied in taking lunar pictures varies considerably ; it depends on the sensitiveness of the chemicals, on the temperature, on the altitude of the moon and her phase. An almost imperceptible mist in the atmosphere will sometimes double the time of exposure, but, curiously enough, a bright fleecy cloud passing over the moon scarcely stops any of the actinic rays. I have recently produced an instantaneous picture of the full moon, and usually get strong pictures of the moon in that phase in from one to five seconds. The moon as a crescent, under like circumstances, would require about 20 to 30 seconds, in order to obtain a picture of all the parts visible towards the dark limb. Development of the Picture.—Of all the developing mixtures tried, I give the preference to the aceto-pyrogallic acid solution, which is generally used in the ordinary proportions ; namely, pyrogallic acid, three grains; glacial acetic acid, one fluid drachm;; distilled water, three fluid ounces; but, in cold weather, I sometimes reduce the quantity of acetic acid to one half, to render the solution more active. The developing fluid retains its properties for a week or more after mixing. It is desirable to pour out the requisite quantity of fluid 138 REPORT—1859. in a small vessel, and to place it in readiness, before the plate is removed from the bath and put into the slide, so as to prevent any delay after the plate has been exposed in the telescope. This precaution obviates the staining which arises sometimes by partial drying of the film. The addition of nitrate of silver to aid in bringing out the picture must be avoided ; pictures thus intensified will not bear any magnifying power, and are comparatively worthless. Hence it will be seen how all-important it is to have the bath and collodion in their most sensitive condition. The negative should not be developed too strongly, as such pictures never copy so well as those moderately but distinctly brought out. Such small photo- graphic pictures as those of Jupiter and Saturn present many obstacles to their development, on account of the difficulty of discerning them during the operation ; for the focal image of Jupiter in my telescope, even when the planet is in opposition, is only about =th of an inch in diameter. After the development of the picture to the desired point, the further development is arrested by pouring a quantity of water on the plate, and a vessel containing water should be at hand for this purpose. ‘ Fixing the Picture-—By preference I use hyposulphite of soda for fixing ; after fixing, the plate is washed under the tap of a cistern of water for a short time, and then examined with a lens. If worth retaining, the epoch of the picture, and other particulars are recorded at the back with a writing dia- mond. The plate is then washed again, front and back, in a stream of water, and placed face upwards on a tripod stand, duly levelled; rain-water* is poured on the collodion, and from time to time this is poured off and fresh poured on, in the meantime other photographs are proceeded with. After half an hour or more, the plate is thoroughly washed in a stream of rain- water, and placed edgewise on blotting-paper against the wall, to drain and dry. a een next morning, the negatives are warmed before a fire, and varnished with Scehnée’s varnish}, which is the only description I have found to stand. I am careful to filter the varnish before using ; otherwise specks might be transferred to the photograph. It is very desirable to var- nish the plates as soon as they are dry, for, if left unvarnished for any length of time, they can never be varnished evenly. Desiderata in the Machinery for driving the Telescope. As in the production of celestial photographs some seconds of exposure are requisite, it is essential to have a clock-work driver to the telescope, which works uniformly and smoothly, and which is also capable, when lunar pictures are to be taken, of ready adjustment to the ever-varying lunar time. Lunar time, it will be recollected, differs from sidereal time, in consequence of the moon’s variable motion in her orbit in a direction opposite to that of the apparent diurnal movement of the stars. A driving clock, if adjusted to follow a star, must be retarded therefore, more or less, in order to follow the moon. In my own telescope, this is at present effected by altering the length of the conical pendulum or friction governor, thus altering the time of its rotation (or double beat), and this plan, or some modification of it, is universal. My experience, however, has pointed out several inconveniences in thus changing the speed of the governor or pendulum,and it is myintention to make such alterations in the construction of the clock as will enable me * In preparing the bath and developing solutions, distilled water must be employed, but filtered rain-water answers very well for washing the photographs. + Sold by Messrs, Gaudin, 26 Skinner Street, London. ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 139 to alter the going of the telescope without changing the rate of the pendulum. This I propose to do by substituting an arrangement, similar to that known in mechanism as the dise and plate, for the wheel-work now connecting the machinery of the clock with the pendulum ; the dise and plate being capable of producing a variable motion, according as the disc is nearer to or farther from the centre of the plate. The pendulum will, by the proposed plan, be driven by frictional contact, and, having employed this system in other machinery, I feel persuaded that its application to the clock-driver will not be attended with difficulty or inconvenience. The moon, besides her motion in right ascension, has also a motion in declination, which is greatest when she is situated in one of the nodes formed by the intersection of the plane of the moon’s orbit and the plane of the earth’s equator, and is least when situated 90° from these nodes, where it vanishes. As this motion is at times very considerable, it is evident that, with a telescope made only to rotate round the polar axis, the best results will be obtained, all other circumstances being alike, when the motion in declination is at zero. Assuming that, on the average, 15 seconds are necessary for taking a lunar photograph, the moon may have shifted upwards of 4!' of arc in declination during that period ; and evidently many details would be lost and the others considerably distorted. In order to ensure the most perfect results under all circumstances, it is desirable to give a movement to the declination axis of the telescope simultaneously with the movement of the polar axis. Hitherto, so far as I am aware, no means have been devised to effect this, but the requisite adjustable motion might be transmitted by means of the disc and plate above described, from the driving-clock, although its pendulum moves with a uniform velocity. Lord Rosse’s Method.—In my original method of taking the pictures by means of the sliding eye-piece before spoken of, both motions in right ascension and declination were provided for by adjusting the slide in the diagonal parallel with the moon’s apparent path. Lord Rosse, at a subse- quent period, applied a clock-movement to such a slide, and made some experiments in celestial photography*; but, the telescope being required for other special purposes, it appears that they were not long continued. This motion of the plate-holder does not meet all the exigencies of the case, but if one of his magnificent reflectors were arranged to move bodily along a guide adjustable in the direction of the moon’s path, by means of some such mechanism as I have alluded to, I believe that lunar pictures might be produced of exquisite beauty, because defects in the collodion film and the glass plate would be of less consequence than with telescopes of shorter focal length, the image being larger in the ratio of focal length; for example, even with the three-foot instrument it would be 3 inches in diameter. Degree of Perfection hitherto attained in Lunar Photography. In my own telescope, the picture of the moon is only about 1-;in. in dia- meter ; it might be suggested that the image could be enlarged by means of a combination of lenses before reaching the sensitized plate, but this would have the effect of prolonging the time of exposure, and moreover introduce the disadvantages of the refracting telescope, and the result would not be se good, for even if the moon’s motion in declination were followed automa- tically, still the outstanding atmospheric disturbances before alluded to would remaint. Indeed, if the aperture of the telescope could be considerably increased in relation to its focal length, much finer pictures would be procured, because the time of exposure would be shortened. In practice it * Monthly Notices of the Roy. Ast. Soc. vol. xiv. p. 199. + Ibid. vol. xviii. p. 17. 140 REPORT—1859. has been found preferable not to magnify the focal image, but to take enlarged positive copies on glass direct from the original negative, by means of an enlarging camera, and in this way the impressions, 8 inches in diameter, exhibited at the Meeting were produced. In making positive copies, some of the more minute details are, unfortu- nately, always lost, for no means exist by which enlarged positive copies can be produced showing all the treasures of the original negative; a perfect enlarging lens being still a desideratum*. As an instance may be cited the streak in the lunar disc, which Mr. James Nasmyth has called “ the railroad,” indicated in Beer and Madler’s map as a straight line to the east of the crater Thebit between latitude 19° and 23° south, and between longitude 7° and 9° east. In the photograph it is shown to be a crack in the lunar crust with an irregular outline, and the eastern edge is perceived to be depressed below the western, which forms a perpendicular cliff. This, although sharply defined in the negative, is frequently lost in positive copies. For the exami- nation and micrometrical measurement of the minuter details which celestial photography is capable of furnishing, recourse must still be had to the original negative. Notwithstanding the disturbances which arise from the atmosphere, minute irregularities in the driving-clock, and the want of means for following the moon’s motion in declination, I have obtained pictures of the moon that bear examination with the three-inch object-glass of a compound microscope magnifying about 16? times, and which show with good definition details occupying a space less than two seconds in each dimension. Two seconds are equal to about ;1,)th of an inch on the collodion plate in the focus of my telescope, and in the finest photographs, details occupying less than 7 \y 9th of an inch are discernible with the three-inch object-glass; hence much valuable work has already been accomplished. A second on the lunar sur- face at the moon’s mean distance being about one mile (1°149 mile), it will be evident that selenological disturbances, extending over two or three miles, would not escape detection, if such occur, provided photographs continue to be taken for a sufficiently long period. Lunar Phenomena recorded by Photography. Full Moon.— Variations of apparent Diameter.—By the delineation of our satellite, photography brings out palpably several phenomena which, although well known, are not always present to the mind ; for example, about every 29 days it is stated that there is a full moon, but we see by the photographic picture that there never is a full moon visible to us, except just before or just * May 1860.—As these sheets are passing through the press, the author has been in- formed by Mr. Dallmeyer (son-in-law of the late Mr. Andrew Ross) that he has brought his investigations on this subject to a successful termination, and that he has just produced enlarging and diminishing lenses which copy without any sensible distortion or dispersion. ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 141 after a lunar eclipse, or at all events except when the sun, earth, and moon are very nearly in the same plane; at all other periods of the full moon we are unfavourably situated for seeing the whole of the illuminated hemisphere. Moreover, the different apparent diameter of the moon at various times, dependent on her distance from the earth, comes out in unmistakeable pro- minence in a.collection of photographs ; for the pictures taken with my reflector vary in diameter from one inch to one inch and nearly two-tenths (10053 inch to 1°1718 inch, being at the moon’s mean distance 1:0137 inch). When positive enlarged copies are made, it is easy to obtain all the pictures of exactly the same dimensions by the adjustment of the distance of the negative to be copied from the lens of the camera ; and my enlarging camera is furnished with screws to facilitate the adjustment of the distance of the object to be copied, and also that of the focusing screen. Libration—We are familiar with the terms “ diurnal libration,” and libration in “ latitude” and “longitude,” yet it is difficult to realize the great amount of disturbance in the aspect of the moon’s disc, and the direction of the displacement from the mean position which these several causes produce unless aided by photography, when we see them palpably before us. The diurnal or parallactic libration never exceeds 1° 1"5; the direction of the displacement in the markings on the lunar disc which it produces is variable, and is dependent partly on the position of the observer. The poles of the moon at the epoch of Mean Libration are situated in the periphery, and the equator and all parallels of latitude are straight lines ; the circles of longitude being more or less open ellipses, varying from a straight line in the centre to a circle at the periphery. This occurs when our satellite is either in perigee or apogee (when the libration in longitude is at a minimum), and she is also situated in one of the nodes of her orbit (when the libration in latitude vanishes): the nodes, apsides, and moon would, under these circumstances, be in the same line. Libration in Longitude merely causes a change of place in the various circles of longitude, which still continue to be more or less open ellipses ; the parallels of latitude straight lines. Those lunar craters, however, situated on the central meridian at the epoch of mean libration would be ona straight line, but, at the periods of maximum eastern or western libration, they would be seen arranged on a semi-ellipse, whose conjugate diameter is 0°1377, the moon’s diameter being unity. Therefore a point at the centre of the moon's equator becomes shifted by the sum of the librations to the east and to the west to the extent 142 REPORT—1859., of more than }th of the moon’s diameter, namely 0-0688 to the east, and the same quantity to the west of the mean position. On account of perspective, the effect of libration in longitude is much less apparent on the eastern and western peripheral meridians, which shift towards the centre by a quantity equal only to z4,th of the moon’s diameter (0:0048). The equator and its parallels, which at the period of mean Libration in Latitude were straight lines, become more or less open ellipses under other circumstances; the ratio between the conjugate and transverse axes of all the parallels being constant for a given inclination of the lunar axis. At a maximum libration in latitude the equatur becomes an ellipse, whose con- jugate axis is 0°1181; the transverse axis being equal to the diameter of the moon considered as unity: so that a point in the centre of the equator is shifted 0°059 of the diameter to the north or to the south by a maximum northern or southern libration, and will move by the sum of these librations to an apparent extent of §th of the diameter of the lunar disc. The apparent motion of the north and south poles towards the centre is on account of perspective only x4,th of the diameter (0:0035). Libration in latitude also causes a change in the ellipses which delineate the meridians, causing an inclination of their axes to the line joining the poles, and also a change in the ratios of their transverse to their conjugate axes. For example, the meridian distant 7° 55! from the centre (this being the position of central meridian at a maximum libration in longitude) would have its transverse axis inclined 0° 56'3 to the pole, the conjugate axis being no longer 0°1377 but 0°1368 of the transverse. The peripheral meridians ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 143 would no longer be semi-circles, but semi-ellipses, whose conjugate diameter is equal to 09965, and whose transverse diameter is inclined 90° to the pole. Stereoscopic Pictures of the Moon.—Taking advantage of the libration, we may, by combining two views taken at sufficiently distant periods, produce stereoscopic pictures which present to the eyes the moon as a sphere. It _ has been remarked by the Astronomer Royal, that such a result is an experi- mental proof of the rotundity of our satellite. A dispute has been going on between photographers as to the proper angle for taking terrestrial stereo- scopic pictures, and I infer that one side of the disputants would consider my arrangement of moon-pictures to produce stereographs unnatural, because under no circumstances could the moon itself be so seen by human eyes; but, to use Sir John Herschel’s words, the view is such as would be seen by a giant with eyes thousands of miles apart: after all, the stereoscope affords such a view as we should get if we possessed a perfect model of the moon and placed it at a suitable distance from the eyes, and we may be well satisfied to possess such means of extending our knowledge respecting the moon, by thus availing ourselves of the giant eyes of science. It does not follow as a matter of course that any two pictures of the moon taken under different conditions of libration will make a true stereoscopic picture ; so far from this being the case, a most distorted image would result, unless attention be paid first to the selection of the lunar pictures, and then to their position on the stereoscopic slide. It is possible to determine before- hand, by calculation, the epochs at which the two photographs must be taken in order to produce a stereoscopic picture ; but so many circumstances stand in the way of celestial photography, that the better course is to take the lunar photographs on every favourable occasion, and afterwards to group such pictures as are known to be suitable. A little consideration of what has been before stated will show that two lunar pictures, differing only by libration, either in longitude or in latitude, will give a true stereoscopic effect, provided the angular shifting is suffi- ciently great. On the other hand, if the two pictures differ both by libration in latitude and in longitude, they will give a true stereoscopic picture provided they satisfy the following condition. Suppose a point in the centre of the equator, when the moon is in a mean state of libration, has become shifted at the epoch of picture A in any given direction, and let an imaginary line pass through that point and the centre of the lunar disc, if at the epoch of picture B the point lies anywhere in the direction of that line, then a true stereo- graph will be obtained, provided the two pictures be suitably placed in the stereoscope. 144 REPORT—1859. Assuming the space between the eyes to be 27 inches, and the nearest distance for distinct vision to be about 10 inches, we find 15° 48! as the maximum stereoscopic angle. The possible shifting of the position of an object on the lunar disc from east to west by libration in longitude may amount to 15° 50', which is almost identical with the assumed maximum stereoscopic angle, and the displacement from north to south, by libration in latitude, never exceeds 13° 34, which falls within that angle. By the joint effect of a maximum libration in longitude and latitude, a point on the lunar surface may, however, be shifted nearly 21°, which is greater than that under which an object could be viewed by the eyes. * The centres of these diagrams should be 23 inches distant to give a stereoscopic picture. ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 145 An exaggerated protuberance of the central portion of the moon might result from the combination of two pictures obtained, at two epochs of maxima, in directions diagonally opposite, and the moon would appear some- what egg-shaped. We may convince ourselves that this would be the case, by viewing, in the stereoscope, two suitably drawn orthographic projections of the lines of longitude and latitude of the sphere, especially if we purposely exaggerate the angle still more; for example, if we make the libration in latitude the double of what it is in reality. At the meeting at Leeds last year, there were exhibited some of my stereo- scopic lunar pictures 8 inches in diameter, and an apparatus constructed expressly for viewing them. The instrument is of similar construction to Wheatstone’s reflecting stereoscope ; but, the objects being transparent, the usual arrangements and adjustments are considerably modified. Prisms with slight curvatures worked on their surfaces are employed, instead of mirrors, for combining the pictures which can be revolved and moved horizontally and vertically in order to place them in the true position. The effect of rotundity is perfect over the whole surface ; and parts which appear like plane surfaces in a single photograph, in the stereoscope, present the most re- markable undulations and irregularities. Light and Shade in the Photograph as compared with that of the Optical Image.—Portions of the moon, equally bright optically, are by no means equally bright chemically ; hence the light and shade in the photograph do not correspond in all cases with the light and shade in the optical picture. Photography thus frequently renders details visible which escape observa- tion optically, and it therefore holds out a promise of a fertile future in sele- nological researches ; for instance, strata of different composition evidently reflect the chemical rays to a greater or less extent according to their nature, and may be thus distinguished}. The lunar surface very near the dark limb is copied photographically with great difficulty, and it sometimes requires an exposure five or six times as long, to bring out completely those portions illuminated by a very oblique ray, as others, apparently not brighter, but more favourably illuminated :—the high ground in the Southern hemisphere of the moon is more easily copied than the low ground, usually called seas, which abound in the Northern hemisphere: from these circumstances I ventured, in another placet, to suggest that the moon may have an atmo- _* These diagrams should be 23 inches from centre to centre to give a stereoscopic icture. , + Professor Phillips has also noticed this difference between the visual] and actinic brightness of portions of the lunar surface. Report of the Brit. Ass., 1853, Section A. p. 16. { Monthly Notices Roy. Ast. Soc. vol. xviii. pp. 18 and 111. 1859. L 146 REPORT— 1859. sphere of great density, but of very small extent, and that the so-called seas might be covered with vegetation. ‘This idea respecting a lunar atmosphere has, I am inclined to believe, received some confirmation from a recent observation of Father Secchi’s, that the lunar surface polarizes light most in the great lowlands and in the bottoms of the craters, and not appreciably on the summits of the mountains. Radiating Lines in the Moon’s Disc.—The mountain peak in the centre of Tycho, about one mile in height, is very distinct in the photographs, and under favourable circumstances the details in the interior of the crater are well shown. The external slopes under all illuminations are darker in the photograph than the internal walls and the bottom of the crater. Tycho would appear to have been the focus of a wonderful disturbing force which broke up the moon’s crust nearly over the whole visible surface, for radiating lines converge in that conspicuous volcano, like so many circles of longitude, and cannot fail to attract attention. Several theories have been suggested to account for these radiating lines; by studying a series of photographs taken under different conditions of illumination one becomes convinced that they are due to furrows in the lunar surface*. They are in some cases overlaid by craters which must have been formed at a subsequent period; and in other eases the furrow has dislocated the crater, which must therefore have previously existed. One very remarkable Furrow fully fifty miles broad, extending from Tycho over 45° of latitude in a north-easterly direction, is the deepest on the lunar surface. The eastern ridge of this furrow skirts Mount Heinsius, and the western ridge extends to Balliald and Euclides, where the furrow becomes very shallow, but is traceable as far as Kepler. Another conspicuous furrow runs from Tycho in a north-westerly direc- tion nearly up to the northern limb of the moon, and extends over 100° of latitude, passing through Menelaus and Bessel in the Mare Serenitatis through a crater (marked E in Beer and Madler’s map) at the head of a pro- montory running into the Lacus Somniorum, when it is crossed by another furrow extending tangentially to the Apennines. The intersection of these streaks resembles the letter X, and indicates another focus of disturbance near the crater E in north latitude 35° and west longitude 24°. The main furrow from Tycho continues on through the crater Plana, leaving Burg untouched on the east, and terminates to the south of Strabo in north lati- tude 60° and west longitude 45°. A furrow best seen about the full moon or a little after, extends from Tycho, though not quite continuously, through the Mare Nectares, traver- sing the crater A on the west of the crater Theophilus ; sweeping in a curve eastward, it leaves Tarantius on the west, and crosses the bright crater Proclus, forming an eastern tangent to Berzelius. Leaving Endymion to the south-east, it forms the southern boundary of the Mare Humboldti- anum in north latitude 70° and west longitude 90°, having traversed 110 degrees of latitude. A remarkable focus of dislocation exists in the Mare Fcecunditatis in lati- tude 16° south and longitude 50° west, which also, by the crossing of the lines of disturbance, looks like another letter X in the photograph. The radiating lines of dislocation are so numerous that it would be impossible, within reasonable limits, to describe any but the principal ones ; I should state, however, that they must not be confounded with the sinuous lines which radiate from Copernicus and other lunar craters, and which are © markedly different in character and origin. * Monthly Notices Roy. Ast. Soc. vol. xviii. p.111. ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 147 Value of Photography in the Production of Selenographical Charts. Pictures of Copernicus may be cited as an example of the aid photography would afford in mapping the lunar surface: this becomes especially apparent when an original negative is examined with a compound microscope. The details brought out in and around this crater in a fine negative by a three-inch object-glass are quite overwhelming from their number and variety. Not only the elaborate network of sinuous radiating lines on the exterior of Copernicus, but also the terraces in the internal walls of that wonderful volcano, the double central cone, the curvature of the sole of the crater, and its polygonal form, all appear in vigorous outline. Again, photographs of the Apennine ridge, under different illuminations, are among the most beautiful of the results of the application of the art to selenography ; it renders conspicuously evident many details of tint and form in that extensive ridge, which would escape the most careful scrutiny of the visual picture unless attention was previously directed to them by the pho- tograph. Unaided by photography, it would indeed be almost hopeless to attempt a correct representation of that wonderful chain of mountains, affected as its form is, on account of its vast extent, by libration, and also on account of the changes in the shadows occasioned by the varying direction of the illumination. Aided by my collection of pictures, I hope to be able to acquit myself in a creditable manner of the trust I have accepted, and to contribute that quota of the lunar surface allotted to me by the British Association. If, at a future period, the entire lunar surface is to be again mapped down, photography must play an all-important part, for, as Messrs. Beer and Madler remarked in their invaluable work on the moon, it is quite impossible to com- plete even a tolerably satisfactory representation of our satellite in those rare and short moments when the mean libration occurs. One is therefore obliged to observe the moon under many different conditions of libration, and to reduce each measurement and sketch to the mean before the mapping can be proceeded with; for not only the position, but also the shape of the objects is altered by libration even from one evening to another. On the other hand, with photography at command, we may obtain in a few seconds pictures of the moon at the epochs of mean libration, and accumulate as readily a great number of records at other times. The latter would furnish, after reduction to the mean, a vast number of normal positions with which the more minute details to be seen with the telescope might be combined. By means of a microscope, with a camera-lucida prism fixed on the eye- piece, enlarged drawings are readily made of different dimensions by varying the magnifying power and the distance of the paper from the eye-piece ;_ with a normal magnifying power of seventeen times linear, drawings of lunar craters can be conveniently made of the exact scale used by Beer and Madler for the large edition of their maps, by simply placing the drawing paper at the proper distance. These drawings may then be rendered more complete from time to time by filling in the minuter details by actual observation, and in this way materials accumulated for a selenographical chart such as even the skill and perseverance of a Madler could not hope to accomplish. Photography of the Planets. Occasionally I take photographs of the fixed stars, and among others have made pictures of the double star Castor, but, as a general rule, I leave the fixed stars under the able custody of the Harvard Observatory, Cambridge, U.S., and devote my attention chiefly to the moon, making, however, from L2 148 REPORT—1859. time to time, photographs of the planets under the rare circumstance of a quiescent state of the atmosphere. In photographing the planets, it is sometimes advantageous to take several pictures on the same plate; this can be conveniently done with my tele- scope, because the driving clock is connected with the telescope by means of a peculiar spring clutch formed of two face-ratchet-wheels. When one picture has been taken, the image is shut off, and the ratchet disconnected, so that the telescope remains at rest, the clock continuing to go. During the interval of rest, which interval is conveniently regulated by the passage of a certain number of teeth of the moving half of the clutch, the planet will have moved through a short distance in its diurnal are; and when the clock has been again thrown into gear, the image will fall on another part of the plate. In this way, four or five images of a planet, for example Jupiter, may be obtained in a very short time. These images are arranged at equal distances along an are of right ascension, and afford a ready means of determining the angle of position of the belts, &c., as was proposed by the late Professor Bond with respect to the angle of position of double stars. Relation of Actinie Power to Luminosity.—I have alluded before to the difference in the optical and photographic picture of the moon ; another very remarkable result of photography is the great difference which has been proved to exist in the relation of actinic power to luminosity of the various celestial objects. For example, the occultation of Jupiter by the moon, on November 8th, 1856, afforded an excellent opportunity for comparing the relative brightness of our satellite and that planet. On that occasion, Jupiter appeared of a pale greenish tinge, not brighter than the crater Plato, and, according to my estimate, of about one-third the general brillianey of the moon; but the actinic power of Jupiter’s light was subsequently found to be equal to fully four-sixths or five-sixths of that of the moon*. Saturn required twelve times as long as Jupiter to produce a photograph of equal intensity on an occasion specially favourable for making the experi- ment; yet I obtained a picture of Saturn together with that of the moon in 15 seconds on May the 8th of the present year, just as the planet emerged from behind the moon’s disc. The picture of the planet, although faint, is sufficiently distinct to bear enlarging. With two pictures of the moon and a planet (or a bright fixed star) taken at a short interval at the period of an occultation, or near approach of a planet or star by the moon, we may obtain a stereoscopic picture which would make the moon (seen, of course, as a flat dise) appear nearer than the planet or star. Stereoscopic Pictures of the larger Planets——Photographs of the planet Jupiter, although far inferior hitherto to the optical image seen with an eye- piece, show the configuration of the belts sufficiently well to afford us the means of producing stereoscopic pictures; all' that is necessary is to allow an interval to elapse between the taking of the two pictures, so as to profit by the rotation of that planet on its axis. In the space of 26 minutes the planet will have rotated through the 15° 48! necessary to produce the greatest stereoscopic effect. Mars would, in 69 minutes, have rotated through the same angle, and, as his markings are very, distinct, we may hope to obtain stereoscopic views of that planet. ‘ee- The markings on the other planets are too faint to hold out a promise of similar results. Although this is the case with respect to Saturn, the ap- * Monthly Notices Roy. Ast. Soc. vol. xviii. p. 55. ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 149 parent opening and closing of his ring as he revolves round his orbit affords us the means of obtaining a stereoscopic picture. Thus photographic reductions of the two original drawings which I made in November 1852 and March 1856 placed in the stereoscope (in such a manner that the major axes of the rings”are at right angles to the line joining the eyes) give a picture in which the planet appears as a spheroid encircled by his system of rings, although the difference of position of the two pictures amounts only to7°. And there is no reason why we may not obtain a stereoscopic picture composed of photographs taken actually from the planet. Loss of the Actinic Rays by Reflection. Until very lately, my celestial photographs were obtained by placing the sensitized plate at the side of the tube, opposite to the diagonal reflector of the Newtonian telescope; hence the light, before it reached the plate, was twice reflected. As it requires a very firm support for the diagonal specu- lum, of even a 13-inch mirror, to prevent vibration, the arm carrying this mirror was firmly screwed to the side of the telescope-tube, and rendered im- moveable ; I could not therefore make experiments intaking the pictures direct, that is to say, with the light only once reflected, without some alteration to the diagonal holder. I have, however, within the last few months, contrived an apparatus which permits of the ready removal and replacement of the diagonal mirror without impairing its stability, and celestial pictures are now taken at will, either direct or reflected out at the side of the tube; more- over it requires but a minute to change the apparatus to produce either result. With these means, I am able to make experiments to determine the relative actinic intensity of the light after one or two reflections. The ex- periments are still in progress, and have been begun so recently, that it is scarcely advisable to hazard a conjecture as to the result; but I may say that I am disappointed as to the increased rapidity of the production of a celestial picture by the direct method over the twice-reflection method ; and I am inclined to infer that Steinheil’s result as to the loss by reflection from speculum metal of the luminous ray does not hold as regards the actinic ray. 2 In concluding the first part of this report, I would remark that to photo- graph the moon continuously is a laborious undertaking, and affords full occupation for one observer, who must not fail to pay unremitting attention to the condition of the various chemicals employed, so as to be always pre- pared for a fine night with such as will work. 1 would therefore strongly urge the claims of this new branch of astronomical science to a more ex- tended cultivation than it has hitherto received, with the conviction that it will require the ardent co-operation of many astronomers to develope fully its rich resources. Part I].—Photoheliography at the Kew Observatory. The Photoheliograph erected at the suggestion of Sir John Herschel* at the Kew Observatory has already been described in the Reports of the Kew Committee, 1856-57+ and 18584, and in the Report for the present - ear. It will not, however, be out of place to give some account of the instru- ment as at present actually in use, for, whilst part of the apparatus originally * Report Brit. Assoc, 1854, p. xxxiv. + Id. 1857, p. xxxiv. + Id. 1858, p. xxxiv, 150 REPORT—1859. provided has been found unnecessary, it has been deemed desirable to make some additions to the instrument from time to time. 7 The object-glass of the photoheliograph, it will be remembered, is of 3745 inches clear aperture and 50 inches focal length, but the whole aperture is never used; it is always diminished more or less, and generally to about 2 inches, by a stop placed in front of the object-glass. The focal image of the sun at the mean distance is 0°466 inch. The focal image is not, how- ever, received directly on the sensitive plate, as in the case of taking lunar and planetary photographs, but is enlarged before it reaches it by means of a secondary combination of lenses (an ordinary Huyghenian eye-piece), which increases the picture to about 4 inches in diameter, thus magnifying the image about eight times linear, and diminishing the intensity of the light 64 times. The object-glass (made by the late Mr. Ross) is specially corrected tu en- sure the coincidence of the visual and chemical foci; but, as might be anti- cipated, the rays, after passing through the secondary lens, are in some degree dispersed, and this coincidence of foci no longer exists. It required some considerable time to determine exactly the position of the actinic focus ; ultimately it was proved, after numerous trials, that the best photographic definition is obtained when the sensitized plate is placed from {th to ith of an inch beyond the visual focus, and that this adjustment must be modified to a slight extent according as more or less of the aperture of the object-glass is employed. Difficulties of Photoheliography.—Whilst in lunar and stellar photography many of the obstacles to be overcome arose from the deficiency of photo- graphic power in the unenlarged focal images of those celestial objects, the difficulties which have stood in the way of producing good sun-pictures arose in a great degree from the incomparably greater brilliancy in the sun’s image, even when its intensity was considerably lessened by stopping off a large por- tion of the object-glass, and magnifying the diameter of the image very greatly. In order to overcome these obstacles, recourse was had at an early period to the less sensitive media than wet collodion, such, for example, as are used in the albumen and the dry collodion processes. None of these attempts were, however, productive of sufficiently promising results to encourage the pursuit of the trials in this direction, and I may mention that I made simul- taneous experiments in taking unenlarged pictures in the focus of my reflector, on dry collodion and albumen, with no better result. The surfaces in these processes are indeed very rarely sufficiently free from impurities for the deli- neation of such minute objects as solar spots, and the processes themselves present disadvantages which render them inapplicable to photoheliography. After many unsuccessful trials a return was at last made to the collodion process. Former experience having shown that the shortest exposure possible with the means then at command produced only a solarized image, in which all trace of the sun-spots was obliterated, recourse was had to the interposi- tion of yellow glass between the principal and secondary object-glasses, with the view of diminishing the actinic intensity of the sun’s image; nevertheless only burnt-up pictures were produced. Instantaneous Apparatus.—It will be evident, therefore, that, for the suc- cessful employment of a medium so sensitive as wet collodion, it was absolutely necessary to contrive some means for reducing the time of its exposure to the sun’s influence to an extremely small fraction of a second. Any apparatus placed in front of the object-glass, it was conceived, would have the disadvan-- tage of cutting off the aperture by successive non-symmetrical portions, and of producing an image less perfect than when the exposed portion of the ob- ject-glass remained always concentric and circular. On the other hand, it was ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 151 seen that a slide with a rectangular opening, if caused to move across the tube in front of the sensitized plate, would in no way distort the picture, but would merely stop off a portion of it, and have the effect, as it moved along, of allow- ing each part of the sun’s image to act in succession on different parts of the collodion, and there to record itself; but a rapidly moving object close to the collodion-plate is so liable to cause a disturbance of dust, and its consequent lodgement on the collodion-film, that the carrying out of the idea in this manner was given up. The late much-lamented Director of the Observatory, Mr. Welsh, suggested the plan which was ultimately adopted with success; instead of placing the sliding apparatus close to the collodion-plate, he proposed that it should be made on a smaller scale and fixed as near the plane of the primary focus as possible. Mr. Beckley has skilfully carried out this suggestion; so that the apparatus answers its intended object most perfectly, and the produetion of a solar picture is now at least as easy as that of a lunar picture. The sliding plate is very light, and moves so freely, that it does not, while in motion, disturb the telescope in the slightest degree ; it is drawn downwards by means of a spring of vulcanized caoutchoue, and as soon as it is released it shoots with great rapidity across the field. The sliding plate has two apertures, one cir- cular, and sufficiently large to permit of the passing of all the rays; this is used for the purpose of focusing on the screen, and also in observing con- tacts of the sun’s limb with the wires to be hereafter described. The second aperture is square, and is fitted with a sliding piece actuated by a screw, which projects beyond the telescope tube ; by means of this screw the aper- ture may be completely closed or readily reduced to a slit of any required width, equal to or smaller than the side of the square opening, a divided scale being affixed to the screw for that purpose. Previous to taking a picture the sliding plate is drawn up just so high that an unperforated part of it completely shuts off the sun’s image ; the plate is held in this position by means of a small thread attached to it at one end, and looped at the other, the loop being passed over a hock on the top of the tube. When the picture is about to be taken, the retaining thread is set on fire, and the rectangular aperture, as soon as the sliding plate becomes released, flashes across the axis of the secondary object-glass, thus allowing the different parts of the sun’s image to pass through it in succession, and to depict themselves, after enlargement, successively on the collodion-plate. Although the time of exposure is so short as to be scarcely appreciable, yet it is necessary to regu- late its duration; and it is therefore controlled by adjusting, 1st, the strength of the vulcanized caoutchoue spring; 2nd, the width of the aperture. In practice, the opening is usually varied between ;)th and z\;th of the dia- meter of the sun’s focal image. No driving Machinery needed, except at the period of a Total Ecelipse.— It will be seen from the foregoing description that the clock-work driving apparatus, described at page xxxv. of the reports for 1857, can be of no ser- vice, because the photograph is taken in so small a fraction of time that no appreciable distortion of the sun’s image would result in the interval by allow- ing the telescope to remain at rest. So rapid is the delineation of the sun’s image, that fragments of the limb, optically detached by the “boil” of our atmosphere, are frequently depicted on the collodion, completely separated from the remainder of the sun’s disc; more frequently still from the same cause the contour of the sun presents an undulating line. Although the clock-work driver is unnecessary for the daily work of the photoheliograph, it may prove of great value on the rare occasions of a total solar eclipse. It is to be hoped that it will enable the contemplated expedi- 152 REPORT—1859. tion to Spain, in July of next year, to obtain a photographic record of the feeble light of the Corona and the Red Flames; but it is by no means certain that their light will be sufficiently intense for that object. Even a failure, however, will prove of some value, for it will show that the image of these phenomena, when enfeebled by an enlargement of eight times linear, possesses too little actinic power to imprint their outline on a collodion-plate in a given number of seconds; and thus data will be furnished for a future period. It is desirable that other astronomers should endeavour to obtain photo- graphs of these data by placing the sensitized plate directly in the focus of the telescope. In taking photographs with the Kew Photoheliograph, the telescope, clamped in declination, is placed a little in advance of the sun, and then clamped in right ascension ; the thread is set on fire as soon as the centre of the sun coincides with the axis ofthe instrument. In order that the operator may know when this is the case, a secondary camera or finder is fixed on the top of the pyramidal tube of the telescope*. ‘This finder consists of an achromatic lens of long focus, which is so placed as to throw an image of the sun on to a plate of brass fixed vertically near the lower or broad end of the tube, and consequently in a convenient position for the operator to see both the image and the retaining thread which holds the slide. The brass plate has ruled on it several strong lines, two of which are just so far apart and so situated as to form tangents to the sun’s limb when the image is exactly central; a lighted match, held in readiness, is at this precise moment applied to the thread, and the slide immediately flashes across the secondary object-glass. Position Wires.—The position of the solar spots in respect. to a normal point is determined by placing a system of wires in a certain known position in the telescope. Originally the wires were four in number, two being fixed at right angles to the other two, the distance between each pair being some- what less than the semidiameter of the sun; so that when one wire of each pair was situated near the sun’s centre the other cut off a small are at the limb. The position of the wires was such that the one pair was parallel to a circle of declination. Some inconvenience was occasionally experienced in consequence of one or other of the four wires obliterating a solar spot ; hence an alteration is now being made in the apparatus for holding the wires. Instead of attaching them to a fixed diaphragm placed: between the two lenses of the secondary object-glass, they will be fastened to a sliding diaphragm with two apertures ; across one of the apertures only will be fixed the wires, so that a photograph may be taken either with or withoutthem. No appreciable distortion in the photographic image of the wires can be detected. The wires will be two in number; they will cross each other at an angle of 90°, and form an angle of 45° with a circle of declination. This system of wires is the same as that proposed by Mr. Carrington and used in his observations of solar spots. It is intended when the apparatus is complete to cbserve the contacts of the sun’s limb with the wires as it passes them in succession each day before commencing a set of photographs, and also immediately after completing them. In order to observe these contacts, the image of the sun and wires will be received on the ground-glass focusing plate, and the times of the several transits noted by viewing the image of the sun and wires through the plate. One photograph will in all cases be taken with the wires, and two or three without the wires, in order to secure all the ° details possible, as well of the facule as of the spots. Degree of perfection attained. Stereoscopic pictures of the Sun.—By over- * Report Brit. Assoc. 1857, p, xxxv. ON CELESTIAL PHOTOGRAPHY IN ENGLAND. 153 exposure of the collodion the faculz first disappear, then the penumbre round the spots, and lastly the spots themselves. In the photograph the difference in the intensity of the sun’s limb and central portions is very marked, but an over-exposure prevents also this from being seen in the photograph. The solar spots and facule delineated by the Kew Photoheliograph bear exami- nation with a lens of moderate power, and show details not visible to the unas- sisted eye. The facule and spots are sufficiently marked to make the sun ap- pear globular when two views taken at a sufficient interval are grouped toge- ther in the stereoscope, as will be seen by the slides now before the Meeting. There is not the same difficulty in obtaining stereoscopic pairs of views of the sun as there is in the case of the moon, because any two views taken at an interval of about a day give a perfectly spherical figure in the stereoscope. When the principal spots are near either limb, two views taken at an interval of two days will combine, and even slight changes in the form of the spots do not prevent the perfect coalition of the two pictures. Having already most fully described the methods pursued and the pre- cautions to be taken to ensure good results in the case of photoselenography, it will be unnecessary for me here to enter into any details of the chemical part of the processes of photobeliography, for the methods are nearly the same in both cases. So far from seeking a surface less sensitive than ordinary col- lodion, it has been found advisable to use both the bath and collodion in a very sensitive condition, though it is not of course necessary to strain this sensitiveness to the utmost extent for solar photography, as in the case of lunar photography. The bath must, however, be always brought back to its best working state by means of oxide of silver, and subsequent addition of dilute nitric acid in case it has become acid by use. The collodion moreover is used in that condition which photographers would call very sensitive. On the Orders of Fossil and Recent Reptilia, and their Distribution in Time. By Professor OWEN. 4 [A communication ordered to be printed entire among the Reports. ] Wiru the exception of geology, no collateral science has profited so largely from the study of organic remains as zoology. ‘The catalogues of animal species have received immense accessions from the determination of the na- ture and affinities of those which have become extinct, and much deeper and clearer insight has been gained into the natural arrangement and subdivi- sion of the classes of animals since Paleontology has expanded our survey of them. Of this the class Reptilia, or cold-blooded air-breathing vertebrates, affords a striking example. In the latest edition of the ‘Régne Animal’ of Cuvier, 1829, as in the ‘Elémens de Zoologie’ of Milne-Edwards (1834-37), and in the more re- cent monograph on American Testudinata by Prof. Agassiz, 4to, 1857, the quadruple division of the class, proposed by Brongniart in 1802, is adhered to, viz. Chelonia (Tortoises, Turtles) ; Sawria (Crocodiles, Lizards); Ophidia (Serpents); Batrachia (Frogs, Newts); only the last group is made a di- stinct class by the distinguished Professor of the United States*, In my former Reports on Fossil Reptiles to the British Association, in 1839 and 1841, it was proposed to divide the class into eight orders, viz. —Ena- * “ After this separation of the Batrachians from the true Reptiles, we have only three args a aa the class Reptiles proper—the Ophidians, the Saurians, and the Chelonians.” —l.c. p. 239. 154 REPORT—1859. liosauria, Crocodilia, Dinosauria, Lacertilia, Pterosauria, Chelonia, Ophidia and Batrachia, which orders were then severally characterized. Subsequent researches have brought to light additional forms and struc- tural modifications of cold-blooded air-breathing animals now extinct, which have suggested corresponding modifications of their distribution into ordinal groups. Another result of such deeper insight into the forms that have passed away has been the clearer recognition of the artificiality of the boun- dary between the classes Pisces and Reptilia of modern zoological systems. The conformity of pattern in the arrangement of the bones of the out- wardly well-ossified skull in certain fishes with well-developed lung-like air- bladders, e. g. Polypterus, Lepidosteus, Sturio, and in the extinct reptiles Ar- chegosaurus and Labyrinthodon ;—the persistence of the notochord (chorda dorsalis) in Archegosaurus, as in Sturio; the persistence of the notochord and branchial arches in Archegosaurus and Lepidosiren; the absence of occipital condyle or condyles in Archegosaurus as in Lepidosiren; the pre- sence of teeth with the labyrinthic interblending of dental tissues in Den- drodus, Lepidosteus, and Archegosaurus, as in Labyrinthodon; the large median and lateral throat-plates in Archegosaurus, as in Megalichthys, and in the modern fishes Arapaima and Lepidosteus ;—all these characters, as were explained and reasoned upon in my lectures at the Government School of Mines (March, 1858), pointed to one great natural group, remarkable for the extensive gradations of development lirking and blending together piscind and reptilian characters within the limits of such group. The salamandroie (or so called ‘sauroid’) Ganoids, e. g. Lepidosteus and Polypterus, are the most ichthyoid, the Labyrinthodonts are the most sauroid, of this annectent group: the Lepidosiren and Archegosaurus are intermediate gradations, one having more of the piscine, the other more of the reptilian characters. Ar- chegosaurus conducts the march of development from the fish proper to the labyrinthodont type ; Lepidosiren conducts it to the perennibranchiate or mo- dern batrachian type. Both forms expose the artificiality of the ordinary class-distinction between Pisces and Reptilia, and illustrate the naturality of the wider class of cold-blooded vertebrates, which I have called Hematocrya*. Reptiles are defined as ‘ cold-blooded air-breathing vertebrates, but the Stren and Proteus chiefly breathe by gills, as did, most probably, the Archegosaurus. The modern naked Batrachia annually mature, at once, a large number of small ova; the embryo is developed with but a small allantoid appendage, and is hatched and excluded with external gills. These are retained throughout life by a few species; the rest undergo a greater or less degree of metamorphosis. Other existing reptiles have comparatively few and large eggs, and the embryo is enclosed in a free amnios and is more or less enveloped by a large allantois; it undergoes no marked transforma- tion after being hatched. On this difference, the Batrachia have been, by some naturalists, separated as a distinct class from the Feptilia. But the number of ova simultaneously developed in the viviparous Land Salamanders is much less than in the Siren, and not more than in the Turtle; and, save in respect of the external gills which disappear before or soon after birth, the Salamander does not undergo a more marked transformation, after being hatched, than does the Turtle or Crocodile}. It depends, therefore, upon the value assigned to the different proportions of the allantois in the embryo of the salamander and lizard, whether they be pronounced to belong, or not, to distinct classes of animals. * aipa, blood, cptos, cold; the correlative group is the ‘ Hemalotherma.’ t The Cecilia may probably depart still further from the type-batrachian mode of d2yelop- ment, and approach more to the type-reptilian mode. ON FOSSIL AND RECENT REPTILIA. 155 This embryonic or developmental character is unascertainable in the extinct Archegosaurus and Labyrinthodon. The signs of affinity of Labyrinthodon to Ichthyosaurus, and those structures which have led the ablest German palzontologists to pronounce the Labyrinthodonts to be true Saurians under the names of Mastodonsaurus, Trematosaurus, Capitosaurus, &c., may well support the conjecture that modifications more ‘reptilian’ than those in Salamandra did attend the development of the young Labyrinthodont. Characters derived from the nature of the cutaneous coverings equally fail to determine the class-characters of Batrachia as contradistinguished from Reptilia, It is true that all existing Batrachia have a scaleless skin, or very minute scales (Cecilia), but not all existing Reptiles have horny seales. The Crocodiles and certain Lizards show a development of dermal bones similar to that in certain placoid and ganoid fishes. This development characterizes the cutaneous system in the Labyrinthodont genus Anisopus ; and in regard to the dermal ossifications of the cranium, the resemblance to the Ganoidei is closer in those ancient forms of Reptilia which exhibit in their endoskeleton unmistakeable signs of their affinity to fishes and batrachians. In the survey which, with a view to communicate its results to the pre- sent Meeting of the British Association, I have made of all the known forms of cold-blooded air-breathing Vertebrates, recent and fossil, I have to ac- knowledge myself unable to define any adequate boundary for dividing them into two distinct classes of Batrachians and Reptiles ; and I am as little able to point out a character dividing the air-breathing from the water-breathing Hematocrya—the Reptiles from the Fishes. In the present Report, therefore, an arbitrary line has been drawn, in order to define its subject, between Lepidosiren and Archegosaurus, and the re- view of the ordinal groups of Reptilia, or air-breathing Hematocrya, will commence with that of which the Archegosaurus is the type. Order I. GANOCEPHALA. The name of Ganocephala, for this group or order (yavos, lustre; cepa), head), has reference to the sculptured and externally polished or ganoid bony plates with which the entire head is defended. These plates include the ‘ post- orbital’ and ‘super-temporal’ ones, which roof over the temporal fosse. There are no occipital condyles. The teeth have converging inflected folds of cement at their basal half. The notochord is persistent, the ver- tebral arches and peripheral elements are ossified, the pleurapophyses are short and straight; there are both pectoral and pelvic limbs, which are natatory and very small; there are large median and lateral ‘throat-plates’ : the scutes are small, narrow, subganoid. Some of the fossils show traces of branchial arches. The above combination of characters gives the value of an ordinal group in the cold-blooded Vertebrata. The extinct animals which manifest it were first indicated by certain fossils discovered in the spherosideritic clay-slate forming the upper mem- ber of the Bavarian coal-measures, and also in splitting spheroidal concre- tions from the coal-field of Saarsbriick near Treves; these fossils were originally referred to the class of Fishes (Pygopterus Lucius, Agassiz). But a specimen from the ‘ Brandschiefer’ of Miinster-Appel presented characters which were recognized by Dr. Gergens to be those of a Salamandroid Reptile*. * Mainz, Oktober 1843.— In dem Brandschiefer von Miinster-appel in Rhein-Baiern habe ich in vorigen Jahre einen Salamander aufgefunden” :—“ Gehort dieser Schiefer der Kohlen-formation ?—in desene falle wire der Fund auch in anderen Hinsicht interessant.” Leonhard und Bronn, Nue Jahrbuch fiir Mineralogie, &c., 1844, p. 49. 156 REPORT—1859. Dr. Gergens placed his supposed ‘ Salamander’ in the hands of M. Her- mann von Meyer for description, who communicated the result of his exami- nation in a later number of the under-cited journal *. In this notice the author states that the Salamander-affinities of the fossil in question, for which he proposes the name of Apateon pedestris, “are by no means demonstrated +..... Its head might be that of a fish, as well as of a lizard or of a batrachian..... There is no trace of bones or limbs.” M. v. Meyer concludes by stating that, “in order to test the hypothesis of the Apateon being a fossil fish, he has sent to Agassiz a drawing with a descrip- tion of it.” Three years later, better preserved and more instructive specimens of the problematical fossil were obtained by Professor von Dechen from the Bavarian coal-fields, and were submitted to the examination of Professor Goldfuss, of Bonn. The latter paleontologist published a 4to memoir on them, with good figures, referring them to a Saurian genus which he calls Archegosaurus, or ‘ primeval lizard,’ deeming it to be a transitional type be- tween the fish-like Batrachia and the Lizards and Crocodiles f. The estimable author, on the occasion of publishing the above memoir, transmitted to the Reporter excellent casts of the originals therein described and figured. These casts were presented to the Museum of the Royal College of Surgeons, London, and were described by me in the ‘ Catalogue of the Fossil Reptiles’ in that Museum (4to, 1854). The conclusions which I then formed as to the position and affinities of the Archegosaurus in the Reptilian class are published in that Catalogue, and were communicated to and dis- cussed at the Geological Society of London (see the ‘ Quarterly Journal of the Geological Society,’ vol. iv. 1848). One of the specimens appeared to present evidence of persistent branchial arches. The osseous structure of the skull, especially of the orbits, through the completed zygomatic arches, indicated an affinity to the Labyrintho- donts ; but the vertebree and numerous very short ribs, with the evidence of stunted swimming limbs, impressed the Reporter with the conviction of the near alliance of the Archegosaurus with the Proteus and other perennibran- chiate reptiles. This conclusion of the affinity of Archegosaurus to existing types of the Reptilian class is confirmed by the subsequently discovered specimens, described and figured by M. von Meyer in his ‘ Palazeontographica’ (Bd. vi. Heft 2. 1857), more especially by his discovery of the embryonal condition of the vertebral column §, i. e. cf the persistence of the notochord, and the restriction of ossification to the arches and peripheral vertebral elements. In this structure, the old carboniferous Reptile resembled the existing Lepidosiren, and thus affords further ground for regarding that remarkable existing animal as one which obliterates the line of demarcation between the Fishes and the Reptiles. Coincident with this non-ossified state of the basis of the vertebral bodies of the trunk is the absence of the ossified occipital condyles, which condyles characterize the skull in better developed Batrachia. ‘The fore part of the notochord has extended, as in Lepidosiren||, into the basi-sphenoid region, * Leonhard und Bronn, Nenes Jahrbuch fiir Mineralogie, 1844, p. 336. Tt “Ob das—Apateon pedestris—ein Salamander-artiges Geschopf war, ist keineswegs ausgemacht.”” + “‘Archegosaurus,’ Fossile Saurier aus dem Steinkohlengebirge die den Uebergang der Ichthyoden zu den Lacerten und Krokodilen bilden,” ‘ Beitrage zur vorweltlichen Fauna des Steinkohlengebirges ’ (4to, 1847), p. 3. § ‘Reptilien aus der Steinkohlen-Formation in Deutschland,’ Sechster Band, p. 61. || Linn. Trans., vol. xviii. p. 333, pl. 24, fig. 2. ON FOSSIL AND RECENT REPTILIA. 157 and its capsule has connected it, by ligament, to the broad flat ossification of expansions of the same capsule, forming the basi-occipital and basi-spheoid late. ; The vertebra of the trunk in the fully developed full-sized animal present the following stage of ossification. The neurapophyses coalesce at the top to form the arch, from the summit of which is developed a compressed, sub- quadrate, moderately high, spine; with the truncate, or slightly convex, summit expanded in the fore-and-aft direction, so as to touch the contiguous spines in the back ; the spines are distinct in the tail. The sides of the base of the neural arch are thickened and extended outwards into ‘ diapophyses’ having a convex articular surface for the attachment of the rib; the fore part is slightly produced at each angle into a zygapophysis looking upward and a little forward ; the hinder part is much produced backwards, supporting two- thirds of the neural spine, and each angle is developed into a zygapophysis with a surface of opposite aspects to the anterior one. In the capsule of the notochord three bony plates are developed, one on the ventral surface, and one on each side, at or near the back part of the diapophysis. These bony plates may be termed ‘ cortical parts’ of the centrum, in the same sense in which that term is applied to the element which is called ‘ body of the atlas’ in Man and Mammalia, and ‘sub-vertebral wedge-bone’ at the fore part of the neck in Enaliosauria. As such ventral or inferior cortical element co-exists with the separately ossified centrum in certain vertebre of the Jchthyosaurus, thus affording ground for deeming them essentially distinct from a true centrum, I have applied the term ‘hypapophysis’ to such independent inferior ossifications in and from the notochordal capsule, and by that term may be signified the sub-notochordal plates in Archegosaurus, which co-exist with proper ‘ ham- apophyses’ in the tail. In the trunk the hypapophyses are flat, subquadrate, oblong bodies, with the angles rounded off: in the tail they bend upwards by the extension of the ossification from the under- to the side-parts of the notochordal capsule, sometimes touching the lateral cortical plates. These serve to strengthen the notochord and support the intervertebral nerve in its outward passage. The ribs are short, almost straight, expanded and flattened at the ends, round and slender at the middle. They are developed throughout the trunk and along part of the tail, coexisting there with the hzemal arches, as in the Menopoma*. The heemal arches, which, at the beginning of the tail, are open at their base, become closed, in succeeding vertebrae, by extension of ossification in- wards from each produced angle, converting the notch intoaforamen. This forms a wide oval, the apex being produced into along spine ; but towards the end of the tail the spine becomes shortened, and the hzemal arch is reduced to amere flattened ring. The size of the canal for the protection of the caudal blood-vessels indicates the powerful muscular actions of the long tail; as the produced spines, from both neural and hemal arches, bespeak the provision made for muscular attachments, and the vertical development of the caudal swimming organ. All these modifications of the vertebral column demonstrate the aquatic habits of the Archegosaurus ; the limbs being, in like manner, modified as fins, but so small and feeble as to leave the main part of the function of eNienine to be performed, as in fishes and Perennibranchiate Batrachia, by the tail. The skull of the Archegosaurus appears to have retained much of its pri- * Principal Forms of the Skeleton, ‘ Orr’s Circle of the Sciences,’ p. 187, fig. 11. 158 REPORT—1859. mary cartilage internally, and ossification to have been chiefly active at the surface, where, as in the combined dermo-neural ossifications of the skull in the sturgeons and salamandroid fishes, e. g. Polypterus, Amia, Lepidosteus, these ossifications have started from centres more numerous than those of the true vertebral system in the skull of Saurian reptiles. The teeth are usually shed alternately; they consist of osteo-dentine, dentine, and cement. The first substance occupies the centre, the last covers the superficies of the tooth, but is introduced into its substance by many concentric folds extending along the basal half. These folds are indi- cated by fine longitudinal straight striz along that half of the crown. The section of the tooth at that part gives the same structure which is shown by a like section of a tooth of the Lepidosteus oxyurus*. The same principle of dental composition is exemplified in the teeth of most of the ganoid fishes of the Carboniferous and Devonian systems, and is carried out to a great and beautiful degree of complication in the Old-red Dendrodonts. The repetition of the same principle of dental structure in one of the ear- liest genera of Reptilia, associated with the defect of ossification of the endo- skeleton and the excess of ossification in the exoskeleton of the head, deci- sively illustrate the true affinities and low position in the Reptilian class of the so-called Archegosauri. For other details of the peculiar and interesting structure of the animals representing the earliest or oldest known order of Reptiles, the Reporter would refer to his article “ Paleontology” in the ‘ Encyclopedia Britannica,’ and to the works by Goldfuss and Von Meyer, above cited. Order II. LasyrinTHopontTia. This name, from \afvpevO0s, a labyrinth, and dédovs, a tooth, refers to the complex structure characterizing the teeth, in the several genera of the order ; in which, also, the head is defended, as in the G'anocephala, by a continuous casque of externally sculptured and usually hard and polished osseous plates, including the supplementary ‘ postorbital’ and ‘supratemporal’ bones, but leaving a ‘foramen parietale+.’ There are two occipital condyles. The vomer is divided and dentigerous. There are two external nostrils. The ver- tebral centra, as well as arches, are ossified, and are biconcave. The pleur- apophyses of the trunk are long and bent. ‘The teeth are rendered complex, at least at the basal part of the crown, by undulations and side-branches of the converging folds of cement ; whence the name of the order. The reptiles presenting the above characters have been divided, according to minor modifications exemplified by the form and proportions of the skull, by the relative position and size of the orbital, nasal, and temporal cavities, and by dermal characters, into several genera; as, e. g. Mastodonsaurus, Ani- sopus, Trematosaurus, Metopias, Capitosaurus, Zygosaurus, Xestorrhytias, &e. The relation of these remarkable reptiles to the Saurian order has been advocated as being one of close and true affinity, chiefly on the character of the extent of ossification of the skull and of the outward sculpturing of the cranial bones. But the true nature of some of these bones appears to have been overlooked, and the gaze of research for analogous structures has been too exclusively upward. If directed downward from the Labyrinthodontia to the Ganocephala, and to certain ganoid fishes, it suggests other conclusions which I have developed in my article “ Paleontology ” above referred to. * Wyman, ‘ American Journal of the Natural Sciences,’ October, 1843. + The corresponding vacuity is larger in some ganoid fishes. ON FOSSIL AND RECENT REPTILIA. 159 There is nothing in the known structure of the so-named Archegosaurus or Mastodonsaurus that truly indicates a belonging to the Saurian or Croco- ditian order of reptiles. The exterior ossifications of the skull and the canine-shaped labyrinthic teeth are both examples of the Salamandroid modification of the ganoid type of fishes. The small proportion of the fore-limb of the Mystriosaurus in nowise illustrates this alleged saurian affinity, for, though it beas short as in Arcke- gosaurus, it is as perfectly constructed as in the Crocodile ; whereas the short fore limb of Archegosaurus is constructed after the simple type of that of the Proteus and Siren. But the futility of this argument of the sauroid affinities is made manifest by the proportions of the hind limb of Archegosaurus ; it is as stunted as the fore limb: in the Labyrinthodonts it presented larger proportions, which, however, may be illustrated as naturally by these pro- portions in the limbs of certain Batrachia as by the proportions of the limbs of Teleosaurus. Order III. IcutTHyoprTERyYGIA. This name, from iy us, a fish, and rrépvé, a wing or fin, relates to the piscin character of the numerous and many-jointed rays or digits in the fore and hind paddles. The bones of the head still include the supplementary < post- orbital’ and ‘supratemporal’ bones, but there are small temporal and other vacuities between the cranial bones, including a ‘ foramen parietale ;’ there is a single, convex, occipital condyle*; and one vomer, which is edentulous. There are two antorbital nostrils. The vertebral centra are ossified and bi- concave. The pleurapophyses of the trunk are long and bent; the anterior ones with bifurcate heads. The teeth have converging folds of cement at their base, are implanted in a common alveolar groove, and are confined to the maxillary, premaxillary, and premandibular bones; the premaxillaries much exceeding the maxillaries in size. The orbits are very large; the eyes were defended by a broad circle of sclerotic plates. ‘The limbs are natatory, with more than five multiarticulate digits ; there is no sacrum. With the retention of characters which indicate, as in the preceding orders, an affinity to the higher Pisces Ganoidei, the present exclusively marine Rep- tilia more directly exemplify the Ichthyic type in the proportions of the pre- maxillary and maxillary bones, in the shortness and great number of the bi- concave vertebre, in the length of the pleurapophyses of the vertebra near the head, in the large proportional size of the eye-ball and its well-ossified sclerotic coat, and especially in the structure of the pectoral and ventral fins. Order IV. SAUROPTERYGIA. The fins in this order of marine reptiles do not include more than five digits and resemble those of the turtles (Chelone) amongst existing Reptiles ; hence the name proposed, from cadpos, a lizard, and rrépvg. There are no post- orbital and supratemporal bonest: the skull shows large temporal and other vacuities between certain cranial bones, including a foramen parietale : there are two antorbital nostrils: the teeth are simple, in distinct sockets of the premaxillary, maxillary, and premandibular bones: they are very rarely pre- sent on the palatine or pterygoid bones. The maxillaries are larger than the premaxillaries. Limbs natatory ; with not more than five digits. There is a sacrum of one or two vertebre for the attachment of the pelvic arch in some: there are numerous cervical vertebrae in most. The pleurapophyses have simple heads ; those of the trunk are long and bent. * This character is retained in all the subsequent orders except the Batrachia. t These bones do not reappear in the subsequent orders. 160 REPORT—1859. In the Plhosaurus the neck-vertebre are comparatively few in number, ~ short, and flat. The Sauropterygian type seems to have attained its maximum dimensions in this genus, the species of which are peculiar to the Oxfordian and Kimmeridgian divisions of the Upper Oolitic system. The Polyptychodon of the cretaceous series also attained a gigantic size. M. von Meyer regards the number of cervical vertebra and the length of neck as characters of prime importance in the classification of Reptilia, and founds thereon his order called ‘ Macrotrachelen,’ in which he includes Simosaurus, Pistosaurus, and Nothosaurus with Plesiosaurus. No doubt the number of vertebre in the same skeleton bears a certain relation to ordinal groups: the Ophidia find a common character therein: yet it is not their essential character ; for the snake-like form, dependent on multiplied vertebra, characterizes equally certain batrachians (Cecilia) and fishes (Murena). Certain regions of the vertebral column are the seat of great varieties, in the same natural group of Reptilia. We have long-tailed and short-tailed Lizards; but do not, therefore, separate those with numerous caudal vertebra as ‘ Macroura’ from those with few or none. The extinct Dolichosaurus of the Kentish chalk, with its proceelian vertebra, cannot be ordinally separated, by reason of its more numerous cervical vertebra, from other shorter-necked proccelian lizards. As little can we separate the short- necked and big-headed ampliccelian Pliosaur from the ‘ Macrotrachelians’ of von Meyer, with which it has its most intimate and true affinities. There is much reason indeed to suspect that some of the Muschelkalk Saurians, which are as closely allied to Nothosaurus as Pliosaurus is to Plesiosaurus, may have presented analogous modifications in the number and proportions of the cervical vertebrae. It is hardly possible to contemplate the broad and short-snouted skull of the Stmosaurus, with its proportionately large teeth, without inferring that such a head must have been supported by a shorter and more powerful neck than that which bore the long and slender head of the Nothosaurus or Pistosaurus. The like inference is more strongly impressed upon the mind by the skull of the Placodus, still shorter and broader than that of Simosaurus, and with vastly larger teeth, of a shape indicative of their adaptation to crushing molluscous or crustaceous shells. Neither the proportions and armature of the skull of Placodus, nor the mode of obtaining the food indicated by its cranial and dental characters, permit the supposition that the head was supported by other than a com- paratively short and strong neck. Yet the composition of the skull, its zygo- mata, temporal cavities, and other light-giving anatomical characters, ull bespeak the close essential relationship of Placodus to Stmosaurus and other so-called ‘ Macrotrachelian’ reptiles of the Muschelkalk-beds. I continue, therefore, as in my former ‘ Report’ of 1841, to regard the fin-like modifi- cation of the limbs as a better ordinal character than the number of vertebrze in any particular region of the spine. Yet this limb-character is subordinate to the characters derived from the structure of the skull and of the teeth. If, therefore, the general term Enaliosauria may be sometimes found con- venient in its application to the natatory group of Saurian Reptiles, the essential distinctness of the orders Sauwropterygia and Ichthyopterygia, typified by the Ichthvosaurus and Plesiosaurus respectively, should be borne in mind. The Plesiosaurus, with its very numerous cervical vertebra, sometimes thirty in number, may be regarded as the type of the Sauropterygia or pentadactyle sea-lizards. Of all existing Reptiles, the lizards, and amongst these the Old-world Monitors ( Varanus, Fitz.), by reason of the cranial : vacuities in front of the orbits, most resemble the Plesiosaur in the structure of the skull, the division of the nostrils, the vacuities in the occipital ON FOSSIL AND RECENT REPTILIA. 161 region between the ex-occipitals and tympanies, the parietal foramen, the zygomatic extension of the post-frontal, the palato-maxillary and pterygo- sphenoid vacuities in the bony palate ; and all these are Lacertian characters as contradistinguished from Crocodilian ones. But the antorbital vacuities between the nasal, pre-frontal, and maxillary bones, are the sole external nos- trils in the Plesiosaurs : the zygomatic arch abuts against the fore part of the tympanic, and fixes it: a much greater extent of the roof of the mouth is ossified than in lizards, and the palato-maxillary and pterygosphenoid fissures are reduced to small size: the teeth, finally, are implanted in distinct sockets. That the Plesiosaur had the ‘head of a lizard’ is an emphatic mode of express- ing the amount of resemblance in their cranial conformation: the crocodilian affinities, however, are not confined to the teeth, but are exemplified in some particulars of the structure of the skull itself. In the simple mode of articulation of the ribs, the Lacertian affinity is again strongly manifested; but to this vertebral character such affinity is limited: all the others exemplify the ordinal distinction of the Plesiosaurs from known existing Reptiles. The shape of the joints of the centrums ; the number of vertebre between the head and tail, especially of those of the neck ; the slight indication of the sacral vertebre ; the non-confluence of the caudal hemapophyses with each other; are all ‘plesiosauroid.’ In the size and number of the abdominal ribs and sternum, may, perhaps, be discerned a first step in that series of development of the hemapophyses of the trunk, which reaches its maximum in the plastron of the Chelonia. The connation of the clavicle with the scapula is common to the Chelonia with the Plesiosauri ; the expansion of the coracoid—extreme in Plesiosauri, —is greater in Chelonia than in Crocodilia, but is still greater in some Lacertia. The form and proportions of the pubis and ischium, as compared with the ilium, in the pelvic arch of the Plesiosauri, find their nearest approach in the pelvis of marine Chelonia; and no other existing Reptile now offers so near, although it be so remote, a resemblance to the structure of the paddles of the Plestosauri. Both Nothosaurus and Pistosaurus had many neck-vertebre ; and the transition from these to the dorsal series was effected, as in Plesiosaurus, by the ascent of the rib-surface from the centrum to the neurapophysis ; but the surface, when divided between the two elements, projected further out- wards than in most Plesiosauri. In both Notho- and Pisto-saurus, the pelvic vertebra developes a combined process (par- and di-apophysis), but of relatively larger, vertically longer, size, standing well out, and from near the fore part of the side of the verte- bra. This process, with the coalesced riblet, indicates a stronger ilium, and a firmer base of attachment of the hind limb to the trunk than in Plesio- saurus. Both this structure and the greater length of the bones of the fore- arm and leg show that the Muschelkalk predecessors of the Liassie Plesio- sauri were better organized than they for occasional progression on dry land. Order V. ANOMODONTIA*. This order is represented by three families, all the species of which are extinct, and appear to have been restricted to the Triassic period. In it the teeth are wanting, or are confluent with tusk-shaped premaxillaries, or are confined to a single pair in the upper jaw having the form and proportions of canine tusks. ‘The skull shows a ‘foramen parietale’ and two nostrils: the tympanic pedicle is fixed. The vertebra are biconcave: the pleurapophyses * avopos, lawless; ddovs, tooth. 1859. M 162 REPORT—1859. of the trunk are long and curved, the anterior ones having bifureate heads : there is asacrum of four or five vertebra, forming, with broad iliac and pubic bones, a large pelvis. Limbs ambulatory. Family Dicynodontia *. A long ever-growing tusk in each maxillary bone : premaxillaries connate and forming with the lower jaw a beak-shaped mouth, probably sheathed with horn. This family includes two genera, Dicynodon and Ptychognathus, all the known species of which are founded on fossils from rocks of probably triassic age in South Africa. Family Cryptodontia+. Upper as well as lower jaw edentulous, The genus Oudenodon closely conforms to the Dicynodont type, and the species are from the same rocks and localities. Family Gnathodontiat. Two curved tusk-shaped bodies holding the place of the premaxillaries, and consisting of confluent dentinal and osseous substance, descending in front of the ‘symphysis mandibule.’ These bodies are homologous with the pair of confluent premaxillary teeth and bones in the existing New Zealand amphiccelian lizard Fhynchocephalus ; they are analogous to the tusks in the Dicynodonts, and must have served a similar purpose in the extinct reptiles (Rhynchosaurus) of the New Red (Trias) Sandstone of Shropshire, in which alone, this structure, with an otherwise edentulous beak-shaped mouth, has hitherto been met with. The Rhynchosauroid reptile from the sandstone of Lossiemouth, near Elgin, is described by the Professor in the Government School of Mines, as having palatal teeth ; but its close affinity to the Rhyn- chosaur of Shropshire adds to the probability of the triassic age of the Los- siemouth sandstone. Order VI. Prerosauria §. Although some members of the preceding order resembled birds in the shape or the edentulous state of the mouth, the reptiles of the present order make a closer approach to the feathered class in the texture and pneumatic character of most of the bones, and in the modification of the pectoral limbs for the function of flight. ‘This is due to the elongation of the antibrachial bones, and more especially to the still greater length of the metacarpal and phalangial bones of the fifth or outermost digit, the last phalanx of which terminates in a point. The other fingers were of more ordinary length and size, and were terminated by claws, the number of their phalanges progressively increasing to the fourth, which had four joints The whole osseous system is modified in accordance with the, pessession of wings: the bones are light, hollow, most of them permeated by air-cells, with thin, compact outer walls. The scapula and coracoid are long and narrow, but strong. The vertebrae of the neck are few, but large and strong, for the support of a large head with long jaws, armed with sharp-pointed teeth. The skull was lightened by large vacuities, of which one was interposed between the nostril and the orbit. The vertebree of the back are small, as are those of the sacrum, which were from two to five in number, but combined with a small pelvis and weak hind limbs, bespeaking a creature unable to stand and walk like a bird: the body must have’ been dragged along the ground like that of a bat. The vertebral bodies were united by ball-and-socket joints, the cup being * Sis, twice ; kuvddous, canine-tooth. t xpumros, concealed ; ddods, tooth. £ yvabos, jaw; ddovs, tooth, § wrepoy, Wing ; cadvpos, lizard. ON FOSSIL AND RECENT REPTILIA. 163 anterior; and in them we have the earliest manifestation of the ‘ proccelian’ type of vertebra. The Pterosauria are distributed into genera according to modifications of the jaws andteeth. In the oldest known species, from the Lias, the teeth are of two kinds; a few, at the fore part of the jaws, are long, large, sharp- pointed, with a full elliptical base, in distinct and separated sockets: behind them is a close-set row of short, compressed, very small, lancet-shaped teeth. These form the genus Dimorphodon, Ow. In the genus Rhamphorhynchus, V.M., the fore part of each jaw is without teeth, and may have been encased by a horny beak ; but behind the edentulous production there are four or five large and long teeth, on each side, fol- lowed by several smaller ones. The tail is long, stiff, and slender. In the genus Pterodactylus, Cuv., the jaws are provided with teeth to their extremities : all the teeth are long, slender, sharp-pointed, set well apart. The tail is very short. The Pter. longirostris, Ok., was about 10 inches in length; it is from litho- graphic slate at Pappenheim. The Per. crassirostris, Goldf. was about | foot long; but the Pter. Sedgwickii, Ow., from the greensand, near Cambridge, had an expanse of wing of 20 feet. The above species exemplify the Ptero- dactyles proper. The oldest well-known Pterodactyle is the Dimorphodon macronyz, of the lower lias; but bones of Pterodactyles have been discovered in coeval lias of Wirtemberg. The next in point of age is the Dimorphodon Banthensis, from the ‘Posidonomyen-sehiefer’ of Banz in Bavaria, answering to the Alum- shale of the Whitby lias. Then follows the Pt. Bucklandi from the Stonesfield oolite. Above this, come the first-described and numerous species of Ptero- dactyle from the lithographic slates of the middle oolitic system, in Germany, and from Cirin on the Rhone. The Pterodactyles of the Wealden are, as yet, known to us by only a few bones and bone-fragments. The largest known species are the Pterodactylus Sedgwickii and Pter. Fittoni, from the Upper Greensand of Cambridgeshire. Finally, the Pterodactyles of the middle chalk of Kent, almost as remarkable for their great size, constitute the last forms of Flying Reptile known in the history of the crust of this earth. Order VII. THErcopontTia*, The vertebral bodies are biconcave: the ribs of the trunk are long and bent, the anterior ones with a bifurcate head: the sacrum consists of three vertebrae: the limbs are ambulatory, and the femur has a third trochanter. The teeth have the crown more or less compressed, pointed, with trenchant and finely serrate margins ; implanted in distinct sockets. Teeth of this type, which may have belonged to the loricated saurian Stagonolepis, have been discoyered by Mr. P. Duff in the white-sandstone at Lossiemouth near Elgin, affording additional evidence of its triassic age. The Protorosaurus of the Permian Kupferschiefer of Thuringia appears to have had its teeth implanted in distinct sockets; but the neck-vertebre resemble in their large and strong proportions those of the Pterodactyles ; and the caudal vertebre show the peculiarity, among Reptiles, of bifurcate neural spines. ‘The types of the present order are the extinct genera Theco- dontosaurus and Paleosaurus of Riley and Stutchbury, from probably triassie strata near Bristol ; and the Cladyodon of the New Red sandstone of Warwick- shire, with which, probably, the Belodon of the Keuper Sandstone of Wir- temberg is generically synonymous. The Bathygnathus, Leidy, from New Red sandstone of Prince Edward’s Island, North America, is probably a * OK, a case; ddods, a tooth. M2 164 REPORT—1859. member of the present order, which seems to have been the forerunner of the next. Order VIII. Dinosavurra*. Cervical and anterior dorsal vertebre with par- and di-apophyses, arti- culating with bifurcate ribs: dorsal vertebra with a neural platform : sacral vertebra from four to sixin number. The articular ends of the free vertebrae are more or less flat; but in the cervical become convex in front and concave behind, in some species. The limbs are ambulatory, strong, long and un- guiculate. The femur has a third trochanter in some. The species of this order were of large bulk, and were eminently adapted for terrestrial life : some, e.g., Jguanodon and probably Hyleosaurus, were more or less vegetable feeders ; others, e. g., Megalosaurus, were carnivorous. The Dinosaurs ranged, in time, from the lias (Scelidosaurus, Ow., from Charmouth) to the Upper Greensand (Jguanodon). The Megalosaurus occurs in the lower oolite to the Wealden inclusive. The latter formation is that in which the Dinosauria appear to have flourished in greatest numbers and of largest dimensions. Order IX. Crocopitta. Teeth in a single row, implanted in distinct sockets, external nostril single, and terminal or subterminal. Anterior trunk-vertebree with par- and di- apophyses, and bifurcate ribs ; sacral vertebra two, each supporting its own neural arch. Skin protected by bony, usually pitted, plates. Suborder Amphicelia f. Crocodiles closely resembling in general form the long- and slender-jawed kind of the Ganges, called Gavial, existed from the time of the deposition of the lower lias. Their teeth were similarly long, slender, and sharp, adapted for the prehension of fishes, and their skeleton was modified for more effi- cient progress in water, by both the terminal vertebral surfaces being slightly concave, by the hind limbs being relatively larger and stronger, and by the orbits forming no prominent obstruction to progress through water. From the nature of the deposits containing the remains of the so-modified Croco- diles, they were marine. The fossil Crocodile from the Whitby Lias, de- scribed and figured in the ‘Philosophical Transactions, 1758, p. 688, is the type of these amphiccelian species. They have been grouped under the following generic heads:—Telcosaurus, Mystriosaurus, Macrospondylus, Massospondylus, Pelagosaurus, Afolodon, Suchosaurus, Goniopholis, Poci- lopleuron, Stagonolepis, &c. Species of the above genera range from the lias to the chalk inclusive. Suborder Opisthocelia }. . The small group of Crocodilia, so called, is an artificial one, based upon more or less of the anterior trank-vertebre being united by ball-and-socket joints, but having the ball in front, instead of, as in modern Crocodiles, be- hind. Cuvier first pointed out this peculiarity § in a crocodilian from the Ox- fordian beds at Honfleur and the Kimmeridgian at Havre. The Reporter has described similar opisthoccelian vertebrae from the Great Oolite at Chipping Norton, from the Upper Lias of Whitby, and, of much larger size, from the Wealden formations of Sussex and the Isle of Wight. These specimens probably belonged, as suggested by him in 1841 and 1342||, to the fore part * Servos, terrible; cavpos, lizard. # aygi, both; xotXos, hollow: the vertebra being hollowed at both ends. t OmwoGe, behind ; cot\os, hollow: vertebrz concave behind, convex in front. § Annales du Muséum, tom. xii. p. 83. pl. xxi. || “ Report on British Fossil Reptiles,” Trans. British Association for 1841, p. 96. ON FOSSIL AND RECENT REPTILIA. 165 of the same vertebral column as the vertebra, flat at the fore part, and slightly hollow behind, on which he founded the genus Cetiosaurus. The smaller opisthoceelian vertebra described by Cuvier have been referred by Von Meyer to a genus called Streptospondylus. In one species of Cetiosaurus trom the Wealden, dorsal vertebra, measur- ing 8 inches across, are only 4 inches in length, and caudal vertebra, nearly 7 inches across, are Jess than 4 inches in length ; these characterize the species ealled Cetiosaurus brevis. Caudal vertebrae, measuring 7 inches across and 54 inches in length, frora the Lower Oolite at Chipping Norton, and the Great Oolite at Enstone, represent the species called Cetiosawrus medius. Caudal vertebre from the Portland Stone at Garsington, Oxfordshire, measuring 7 inches 9 lines across and 7 inches in length, have been referred to the Cetiosaurus longus; the latter appears to have been the most gigantic of Crocodilians. Suborder Procelia*. Crocodilians with cup-and-ball vertebra like those of living species first make their appearance in the Greensand of North America (Croce. basifissus and Croc. basitruncatus)+. In Europe their remains are first found in the tertiary strata. Such remains from the plastic clay of Meudon have been referred to Crocodilus isorhynchus, Croc. caelorhynchus, and Croc. Becquereli. In the ‘ Caleaire grossier’ of Argenton and Castelnaudry have been found the Croz. Rallinati and Croc. Dodunii. In the coeval eocene London Clay at Sheppey Island, the entire skull and characteristic partsof the skeleton of Cro- codilus toliapicus and Croc. Champsoides occur. In the somewhat later eocene beds at Bracklesham occur the remains of the Gavial-like Croc. Dixoni. In the Hordle upper eocene beds have been found the Crecodilus Hastingsie with short and broad jaws; and also a true Alligator (Croc. Hantoniensis). It is remarkable that forms of proccelian Crocodilia, now geographically re- stricted—the Gavial to Asia, and the Alligator to America,—should have been associated with true Crocodiles, and represented by species which lived during nearly the same geological period, in rivers flowing over what now forms the south coast of England. Many species of proccelian Crocodilia have been founded on fossils from miocene and pliocene tertiaries. One of these, of the Gavial subgenus (Croc. crassidens) from the Sewalik tertiary, was of gigantic dimensions. Order X. LAcERTILIA. Vertebre proceelian, with a single transverse process on each side, and with single-headed ribs: sacral vertebre not exceeding two. Small vertebre of this type have been found in the Wealden of Sussex. They are more abundant, and are associated with other and more characteristic parts of the species in the Cretaceous strata. On such evidence have been based the Raphiosaurus subulidens, the Coniosaurus crassidens, and the Dolichosaurus longicollis. But the most remarkable and extreme modification of the Lacertian type in the Cretaceous period is that manifested by the huge species, of which a cranium, 5 feet long, was discovered in the Upper Chalk of St. Peter’s Mount, near Maestricht, in 1780. This species, under the name Mosasaurus, is well known by the descriptions of Cuvier. Allied species have been found in the cretaceous strata of England and N. America. The Leiodon anceps of the Norfolk chalk was a nearly allied marine Lacertian. The structure of the limbs is not yet well understood; it may lead to a sub- ordinal separation of the Mosasauroids from the Land-lizards, most of which * mpd, before; KotXos, hollow : vertebra with the cup at the fore part and the ball behind. T Quarterly Journal of the Geological Society, January, 1849, p. 380. 166 REPORT—1859. are represented by existing species, in which a close transition is manifested to the next order, Order XI. Ovnrpta *. Vertebree very numerous, proccelian, with a single transverse process on each side; no sacrum: no visible limbs. The earliest evidence, at present, of this order is given by the fossil ver- tebre of the large serpent (Paleophis, Ow.) from the London clay of Sheppey and Bracklesham. Remainsof a poisonous serpent, apparently a Vipera, have been found in miocene deposits at Sansans, S. of France. A large fossil ser- pent (Laophis, Ow.), with vertebrae showing similar modifications to those in the Crotali, has been discovered by Capt. Sprat, R.N., in a tertiary formation at Salonica. Ophidiolites from CEningen have been referred to the genus Coluber. Order XIT. CHELONIAt. The characters of this order, including the extremely and peculiarly modi- fied forms of Tortoises, Terrapenes, and Turtles, are sufficiently well known. The chief modifications of osseous structure in oolitic Chelonia are shown by the additional pair of bones interposed between the hyosternals and hypo- sternals of the plastron, in the genus Pleurosternon from the upper oolite at Purbeck. It would be very hazardous to infer the existence of Reptiles with the characteristic structure of the restricted genus Yestudo from the foot- prints in the triassic sandstone of Dumfriesshire. But the Reporter concurs in the general conclusions based upon the admirable figures and descriptions in the splendid monograph by Sir Wm. Jardine, Bart., F.L.S., that some of those foot-prints most probably belonged to species of the Chelonian order. An enormous species of true turtle (Chelone gigas), the skull of which measured one foot across the back part, has left its remains in the eocene clay at Sheppey. ‘The terrestrial type of the order had been exemplified on a still more gigantic scale by the Colossochelys of the Sewalik tertiaries. Order XIII. BarraAcuiA}. Vertebree biconcave (Siren), proccelian (Rana), or opisthoceelian (Pipa) ; pleurapophysesshort, straight. Two occipital condyles and two vomerine bones, iu most dentigerous: no scales orscutes. Larvee with gills, in most deciduous, Representatives of existing families or genera of true Batrachia have been found fossil, chiefly in tertiary and post-tertiary strata. Indications of a peren- nibranchiate batrachian have recently been detected by the Reporter in a col- lection of minute Purbeck fossils. Anourous genera (Paleophrynus) allied to the Toad occur in the CEningen tertiaries, and here also the remains of the gigantic Salamander (Andrias Scheuchzeri) were discovered. Summary of the above defined Orders. Province VERTEBRATA. Class HmamMATOCRYA. Sub-class REprivia. Orders. I. Ganocephala. VIII. Dinosauria. II. Labyrinthodontia. IX. Crocodilia. II. Ichthyopterygia. X. Lacertilia. IV. Sauropterygia. XI. Ophidia. V. Anomodontia. XII. Chelonia. VI. Pterosauria. XIII. Batrachia. VII. Thecodontia. * dois, a Serpent. Tt yedw27, a tortoise. t Barpayos, a frog. ON THE MAGNETIC SURVEY OF SCOTLAND. 167 On some Results of the Magnetic Survey of Scotland in the years 1857 and 1858, undertaken, at the request of the British Asso- ciation, by the late Joun Weusu, Esq., F.R.S. By Baurour Srewart, 4.M. Tur much-lamented death of Mr. Welsh, who laboured in science so well and so earnestly, and the last work of whose life was the completion of the observations of the Magnetic Survey of Scotland, has imposed upon the author the less arduous task of reducing those observations. It is now somewhat more than twenty years since the first Magnetic Survey of the British Islands was made, the results of which are recorded by General Sabine in the Report of the British Association for 1838. The General Committee at the Meeting held at Cheltenham in 1856, feeling that the time had arrived when another survey of these islands would be desirable, requested General Sabine, Prof. Phillips, Sir James C. Ross, Mr. Robert W. Fox, and Rev. Dr. Lloyd, to undertake its repetition. It was ultimately resolved that Mr. Welsh should proceed to Scotland, and the Admiralty kindly granted £200 in aid of his expenses. During the summer and autumn of 1857 Mr. Welsh performed the first instalment of his task, confining himself to stations in the interior of Scot- land and on the east coast. In the same season of 1858 he completed the survey, by undertaking the west coast, the Hebrides, and the Orkney and Shetland Isles. ‘This involved much personal fatigue and a great number of observations, all of which were executed with the utmost possible accuracy and scientific attention to details. More was done for Scotland in this survey than in that of twenty years ago. In the interval between the two surveys, improvements had been made in the dip-circle and in the apparatus for measuring the total mag- netic force. ‘These improvements were of course adopted in the instru- ments employed in the late survey ; and, furthermore, observations of decli- nation were made,—a thing which had not been previously attempted. The survey thus divides itself into three parts: the first comprising the Observa- tions of Dip ; the second those of Total Force; and the third those of Decli- nation, which will be discussed in order. Division I.—Dip. The dip-circle (No. 23) was made by Barrow. Two needles were em- ployed, each 34 inches long. The axle of the needle rests on two agate planes, and its position is concentric with, but behind (as regards the observer) the vertical divided circle on which the inclination is read. A moveable arm, concentric with this circle, has two microscopes attached to it, the di- stance between them being 3} inches, so that either extremity of the needle may be brought into the centre of the field of the corresponding microscope. The extremities of this moveable arm form verniers which bear upon the vertical circle, and by means of which the position of the needle may be very accurately determined. In November 1857, the following observations were made with this instrument in different azimuths :-— 168 REPORT—1859. Tanz I. | Magnetic End A End B | Resulting Needle. azimuth. | dipping. dipping. Mesa. | dip. 1 é 68 27°37 | 68 25-25 | 68 26:31 | 68 26-31 30 71 7-12] 71 600| 71 6561] 6¢ o¢75 120 78 50-75 | 78 49°50 | 78 50:12 f 60 78 52°50 | 78 52-00 | 78 52:25 , 150 71 612 | 71 212] 71 4-12¢| 98 2558 2 0 68 24-12 | 68 29-00 | 68 2656 | 68 26-56 30 71 3-00 | 71 9:27| 71 6181) 9 o5.97 | * 120 78 48:25 | 78 45-75 | 78 47-00 60 78 44-87 | 78 51-62 | 78 48-25 : 150 71 400| 71 725 | 71 562s} 59 25°00 In this Table the resulting dips are calculated by the formula cot* é= cot? i+ cot? i!, where dis the true dip, and 7 and 7 the positions of the needle in azimuths 90° apart. These results are satisfactory, and show that any errors due to the axle or to local magnetism in the circle are inappreciable throughout the range of observation; otherwise we should have had greater differences in the result- ing dips. Now the portion of the circle so tested comprehends that used during the magnetic survey ; we may therefore with safety suppose the circle to be free from magnetism and error of axle as far as the results of the survey are concerned. It will also be observed that the dips given by both needles are very nearly the same; and although this amount of agreement did not always hold throughout the survey, yet the average difference be- tween the needles is exceedingly small. It has therefore been thought unnecessary to apply any correction in the case of those stations (very few in number) where only one needle was observed. The following Table exhibits the results of a comparison made at Kew Observatory between the Survey dip-circle (No. 23) and other reliable in- struments, in March 1859 :— Taste II. Ea [nfs Number of ‘ Mean of Circle. | Needle. observations. Dip. both needles. No. 20 ] 4 6B 23:00] | co on. . 2 4 68 24-74 | 68 28°87 33 1 4 68 23-26 a: P 2 4 68 aLne ft SBsses 34 1 4 68 22°17 b 2 4 68 1997 f| 88 2107 23 1 2 68 24-78 fe Me 2 2 68 92-26 5| 68 23:83 30 j 2 68 21-68 i 2 2 68 93-32 ¢| 98 2250 Kew 1 3 68 20°88 i 2 3 68 22-64 f| 98 2176 Mean of all circles ......... 68 22:5 ON THE MAGNETIC SURVEY OF SCOTLAND. 169 It appears from this Table, that, while the mean of all the circles gives a dip of 68° 22!°5, the observations with circle No. 23 give 68° 23'°5, or 1' higher. This difference is so small, that it has been thought unnecessary to apply any constant correction to the dips on account of it. It is therefore pre- sumed that circle No. 23 is calculated to exhibit the true dip at the place of observation. An equal weight has been attached to each of the mean dips obtained at the various stations, without regard to the number of observations made at any station, in accordance with a remark of General Sabine, that an ab- normal result is more likely to be due to local magnetism than to error in observing. The dips have been corrected for secular change to the epoch of Ist January, 1858. The yearly rate of change has been ascertained by com- paring the observations of the present with those of the previous survey. The method is exhibited in the following Table :— Taste III. : : . | Date of | Second | Date of | pifference |Difference of | Yearly rate Station. First Dip. Hirst Dip.| Dip. ao of Dips. |datesin years.| of abceand. i ° i Lerwick......... 73 449 | 1838 | 73 11:9 | 1858 33:0 20 465 Aberdeen ......| 72 27°6 1838 71 49°3 1857 38°3 19 2°02 Kirkwall ......| 73 20°4 1838 72 40°9 1858 39°35 20 1:97 WACK Ji cccccseee 73 19:9 1838 72 39:5 1858 40°4 20 2°02 Golspie teesesls | 72 555 1836 72 25°0 1858 30°5 22 1:39 73 4:3 1838 72 25:0 1858 39°3 20 1:96 Inverness ....-- 72 46°4 1836 diodes 1857 38°5 21 1°83 72 46:2 1838 72 79 1857 38°3 19 2°01 Fort Augustus | 72 40°3 1836 72296 1857 37:7 21 1:80 Berwick.......++ 71 41:9 1838 70 54:8 1857 47-1 19 2°48 Melrose......-.-| 71 36°8 1836 70 54:7 1857 42-1 21 2°00 71 38:0 1837 40 54:7 1857 43°3 20 2°16 PANEOLG | cas.cnc-.| £2 21°9 1836 71 45°9 1857 36°0 21 171 Gretna ....06... 71 29:0 1837 70 46:0 1857 43°0 20 2°15 Edinburgh...... 71 50°3 1836 71 11:2 1857 39°1 21 1:86 71 50:0 1837 71 125 1858 37:5 21 1:79 Glasgow...seree- 72 16 1836 71 26:3 1857 35:3 21 1:68 72 50 1837 71 26°3 1857 38°7 20 1:93 Helensburgh ...| 72 16°7 1836 71 29°6 1857 47-1 21 2°24 72 17:0 1838 71 29°6 1857 47°4 19 2°49 Canpbelton ... 71 55°9 1836 71 14:0 1857 41:9 21 1:99 Cumbray ......| 72 11 1836 71 28°9 1857 32:2 21 1°53 Mean annual rate of decrease= 1°94 ee In reducing the dips to the epoch, a yearly rate of decrease of 1"94, or in round numbers 2’, has accordingly been adopted. No other correction has been applied to the observations. They are thus presented to our view in the following Table :— “UIs "eg [eur ueULIQ Jo pua 4saAy spared Cg “OSTLOH] Sug “Ap JO yseq oyouseu onusay “Yonyy Yysied plo Wor G'S spied OOP ‘sSv10 oul] Wor Wy N spavd QOZ “yorny) ay puryaq spavd OCT ‘ISNOY S,YUUG “APY JO “| OaUseU onuAW OF UIIIM ‘AvIquIND yeary Jo pus “q’N “Bas JO spied | *£LOJBAIOSYO *suapiey o1uvjog *aSNOF] JANOD 91} JO *g spied YET ynoqe ‘uomuo0g 044 uC “qomnyg UByoUIYIE Jo*A\"N*A\ Spars OOZ “qounyD Ysieq JO "A\"N'N Spars QOE *PpOOMIDYJON TIMO'T “MARZ 8.99099 “AI UOTTIG AGATA UBIUOpITeD BUZIID JOM "SAX JIA vB Jey ynoqe ‘jax0F] JO yuosz ur spavd Qey *spunols S,YyLo{UOT “APL uolounr Jo "MA"s spared 9G *suapiey o1Uejog “Aaqqy oy) Jo yseq spavd 00Z REPORT—1859. ur ‘MoTe94g “AI0JVAIOSGO *UOTYLAISGQ JO Bde[q 170 6-96 TL 6-1 9-9T £16 £:86 0-68 LG 194 IZ IZ IZ IZ TZ } } } L-G¢ 1 IZ 04 OL 4 04 4 IZ 4 “8S81 ‘T ‘ure yooda 0} poonpas dq WOIqeIS OU} 4B UvdTy 18-92 TZ 186% TZ { 91-2¢ TL | 29-88 TZ 89-CL TZ eL-Zl U 6L-LT IZ 6:22 TL P68S TL 96-28 TL 89-9 TZ 00-2 TZ ZLGS LL CL-L@ IZ €6-92 IL 1@-¢ TZ c%9 LZ 29-6 OL ZLSe OL 90-96 OL 18-26 02 8LZP OL OF-Gh OL L6-GP OL 4 104 04 4 4 OL 4 04 OL ° T€-9¢ £601 99-69 GL-PG 69-1S LO-8P G1-1G 68-9 6L.G¢ *safog 410q jo uvoy 00-66 69-€6 8E-1& GL-LE Go-FI oL-€L 00-81 63-86 GL-82 GL-FE GLP 00-8 GL.G3 61-86 69-96 ¥6-9 00-G L8-GS LE-PG 61-SG L8-6S 0S-6P GL-bP 69-SP £8.9G oPell GL-6G 6L-Gg 09-69 oF-0G GL-0S 00-€¢ 00-64 TZ 174 IZ IZ 104 1 IZ 1Z 124 1Z IZ WZ 14 IZ IZ IZ i 04 4 04 0 04 04 OL 04 104 04 OL OL OL OL 04 OL ° “ad 9d ‘AI STAV, RNA RR NSN BN BR RNR eR RANE NAN = BNR ANAR NR eS “d[PoIN eo MMOHONNSCAAAN 9F ‘Wd GT Al 02 ‘WV 8% ‘W'd 0G “NV L3 w Y “cc “UOT}LA.IOSGO jo oT} Uva TOIMUIITH dag ‘ sovensseesecnes SI@TISTIDIN, se eeeweeeens ysinqsuayayy a eeeeetesens uojyaqdueg seeeeeres NBOUTION) YOO'T steereseeees SF MGSUa[O HT “ueseossi esses’ sir AB TONGOn *Pteeeeanereeesees MODSBIE) seer eres eerereres OOOH I seteseevecseses TQBIUUIIG verses JVWMIIG TOJMON Pancnpsensesesiee SOTITIN Gp ‘teaeeeseseuserss BUTI * sileysiey *ysanquipa seeeeseoeeereesoos OSOIIOT veewes UN04S1OH CIT SOS UCSC fa} hts (2) "TOTE}g 171 “IMoqaevy JO You (an14) apr v Fey *suapiey o1uRj0g *A10}VAIISGO ‘suapaey o1uejOg “WUT 94} JO 4SaM Sprvk OCT PLM “T'S oyouseu 07 spavk OOP UUT fey) “Seur 07 spared QQ ‘e8vy09 saesiq “yearn Jo spunois ut ‘GUT SULTY plnvorTaAUT JO yWO. ut spas OF *QSULTN 9 JO JUOAy Uy ‘aBaT[op jeyostivpy JO YINOs opIUE T ‘uep -1v8 plo ue ut ‘yoInyO JO ysom TUL Ff “yurg Jo apyseQ plo ay} Jo spunoid dy UL asnoY S,taUUIETG “Ap, JO UoAy UT ‘gidaays Jo yynos spared QOT ‘uepzes [210H *ssauIOAUy JO apseg 942 AvaU TOY HTP “AJA JO uapawes uy “410g Jo (oyousem) "yy Aq “AA Sprvd OOF qoinyg Ystieg Jo (oyouSeur) gq"g sprvd og MU] BIAvURG JO UO UI UOWeUTpEp 94} SasvoriTyg s,auNny -day sojaq spied Oop euro Jo yuRq qjnos uo paasasqo Aqisuazut pue dip ayy, ‘a1v9 aspory Ayjouoq Jo “q’s spars 0g ‘raid yvoq-uieayg Jo YA0N spred OOF ON THE MAGNETIC SURVEY OF SCOTLAND. ed a So oe) ei ~~ J } GPS TL } 0-2 3b LS If } €-66 Tf €-E¢ 6-66 IZ If 0:96 ANA NA ANA NR ANANDA FAANARNARA LANA ARAaARe mA N meh Ma oats OF. i “W'd OF T I 4 “ 91 OL ‘wv 16 OL «88 “ “c af cc z hia * “08 = ea ea peo “cb Go ‘Wd © “Av 9g ‘W'd 06 “WV 8¢ “ 61 “ce 9L “Wd ¢G 4c HG “ 1 “AV 16 sc ZL “ e¢ “cc Ze “ec L “ 6¢ “ LI HHONHMONOCSCS ei | a TM “wd 1% € "wv O¢ IT “. 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II “Wd CE 0 “ UOT}VAIISqO jo ou uLvoyy Il =e et I? ei Il Yorauaary “ydag ¢ ‘sny 9% re Aloe “scst “oye TTT |easuiq se eeeeeeereeeceees atdsjox “OTN TeMsATY Se teeeeerneeeerees YOM IT eaececcetcevces SsoUWM01yS eee eeeeneeeeees eee osinqy, seevesceccvsseovos SSOUIN(T seereceeeree JOAUT YOO'T Seeeeeseerens Seta seereeeeveeeese UISIITTUD **£BMOUIO}S teeesenereeoseone QO70I0g ** plojpeorg se eereeeseereee uryeopAyy BIIVOVWU eg * W9AIONIUITS) * aoUIeqgoy, — ——— “UOT}EIS ON THE MAGNETIC SURVEY OF SCOTLAND. 173 It is now necessary that these observations be combined together by the method of least squares. This method is described by General Sabine, in discussing the Magnetic Observations in Scotland, in the volume of Reports of the British Association for 1836, We are thus enabled to determine the most probable values of three un- known! quantities ; viz. of =the dip at the central position; u=-the angle which the isoclinal line passing through the central position makes with the meridian ; and r=the coefficient, determining the rate of increase of the dip in the normal direction, or that direction which is at right angles to the isoclinal lines. Using all the stations except Tobermorie (where the dip seems to be much increased by local attraction), we obtain the following values of 4, u and r; 6=71°-45', which represents the most probable value of the dip at the central station, lat. 56° 48’ N., long. 4° 19! W.; u, or the angle which the jsoclinal line makes with the meridian, = —71° 29’, or its direction is from N. 71° 29' E. to S., 71° 29! W.; and7, or the rate of increase of dip in the normal direction, =0'556 for each geographical mile, or 53°95 such miles for each half degree of dip. The dip observations made use of in the previous survey of twenty years ago consist of two sets (see Eighth Report of British Association, pp. 88-90). 1. Observations were made at ten stations by Sir James Ross; these give 5=72° 408 at the mean geographical position, 57° 20’ N., and 3° 08! W., and at the mean epoch, August 18, 1838; also u=—62° 39'; r=0'-545. 2, Observations were made at thirty-six stations by General Sabine and Mr. Fox; these give u=—54° 20’; r=0''550; 6=72° 13'2 at the mean geographical position 56° 18' N., and 4° 10' W. at the epoch, September 1, 1836. Let us regard these results as each possessing a weight proportional to the number of stations made use of in obtaining it, and let us reduce them to the epoch Ist January, 1837, by assuming the approximate yearly decrement of dip to be 2’, and the similar increment of the angle —u to be 44/; also let us reduce d to the central station, lat. 56° 48! N., long. 4° 19’ W. This station being the same as that used in the present survey, we have thus the means of comparing the results of both surveys in the following Table :— Taste V. Central Station. Lat. Long. Epoch. 6. Ue r. ° é/ °o 4 ° ‘ io} / ‘ 56 48N./ 4 19 W. |1 Jan. 1837) 72 31:9 —56 03 0°550 56 48N.| 4 19 W. /L Jan. 1858) 71 45:0 —71 29 0°556 We thus see that in twenty-one years the dip at the central station has diminished 46-9, or its yearly rate of decrease is 2'-23; the value of —z, on the other hand, has been increased by 15° 26’, or the isoclinal lines are so much more nearly horizontal than they were in 1837; while 7, or the co- efficient which denotes the change of dip in a normal direction, has altered very little*. * These changes will be rendered obvious by referring to a map appended to this Re- port (Plate 6), in which the isoclinal lines for the two surveys are compared together. 174 REPORT—1859. It has already been remarked, that the difference between the observed and calculated dip for a station is more likely to be due to local attraction than to error of observation. Local attraction, again, may be presumed to depend on the geological formation of the neighbourhood. In the following Table the difference between the observed and calculated dips is compared with the geological character of the station. In this Table, the latitudes and longitudes, unless when the contrary is specified, are obtained from a Map of Scotland published by the Society for the Diffusion of Useful Knowledge, while the geological character of the station is obtained from Prof. Phillips’ Geological Map of Great Britain and Ireland. Tasxe VI. Observed] Dip cal- | Observed ‘ Dip re- | culated | minus Geological character of Station. Lat. | Long. Reed to| by least | calculated ea epoch. | squares.| Dip. ° é ie} eA ° 4 fe] / i Berwick...........- 55 46} 200! 70 54:0] 70 58:4] — 4:4 |Clay-slate. tMakerstoun ...... 55 85 | 2 81 | 70 55:2) 70 55-7} — 5°5 |Felspathie trap. Melrose .......+.065 55 85 | 2 44 | 70 53:9) 70 57:0] — 3:1 |Soft clay-slate. {Edinburgh......... 55 58 3 11] 71 11:5} 71 11:9] — 0:4 |Coal series. Carstairs .,....... 55 43 | 38 40 | 70 55:5} 71 06:8) —11°3 |Coal. GREWAL ss cracce ces: 55 01] 3 03 | 70 45:°2/ 70 40:9} + 4:3 |New Red sandstone. Dumfries ......... 55 05 3 36 | 70 43-2) 70 46:3) — 3:1 |Ditto. Newton Stewart..| 54 56 | 4 28] 70 53°8| 70 469} + 6°9 |Soft clay-slate. Stranraer ......... 54 54 | 5 02] 70 54:8] 70 49:1} + 5:7 |Ditto. AGT, sun opccucepsiase 55 28) 4 38 | 71 05-2| 71 04:6} + 0°6 (Coal. TGlasgow ......... 55 52] 416] 71 25:7) 71 15:1] +10°6 |Ditto. Lamlash ......... 55 31 | 5 05 | 71 05:7| 71 09:0) — 3:3 |Old Red sandstone and trap. TBrisbane ......... 55 49 4 52 | 71 82:0) 71 17:0} +15:0 |Ditto, ditto. Cumbray ......... 55 48 | 4 52 | 71 28:3] 71 166] +11°7 |Old Red sandstone. Helensburgh...... 56 02 | 4 43 | 71 28:5] 71 23:0] + 5:5 |Mica schist. tLochgoilhead ...| 56 10 | 4 54 | 71 166| 71 28:3) —11*7 |Ditto, Campbelton ...... 55 25 | 5 41 | 71 18:3] 71 09:4; + 3:9 |Old Red sandstone and mica schist assuciated with pri- mary limestone. tArdrishaig......... 56 01 | 5 27 | 71 25:2) 7] 26:9} — 1:7 |Chlorite slate. Obany. eBid: 56 27 | 5 26 | 71 29:3] 71 40-4) —11:1 /Trap and Qld Red sandstone. Corpach............ 56 51 | 5 08 | 71 52°7| 71 51:3] + 1:4 |Granite and gneiss. Fort Augustus ...) 57 09 | 4 40 | 72 02:0] 71 58:0 + 4:0 |Mica schist. Inverness ......... 57 28 | 411] 72 07:3) 72 05:2} + 2:1 |Old Red sandstone. LD aii ipcescncaetiecos 57 39 | 319 | 72 07:7] 72 06:2} + 1°5 |Ditto, and oolite. LHR ocaba saboacacne 57 39 | 2 81 | 71 55-9] 72 016} — 5:7 |Gneiss and granite. Peterhead mereeae 57 31} 1 46 | 71 54:2] 71 53:2)| + 1:0 |Granite. Aberdeen ......... 57 09 2 05 | 71 48:9, 71 43:1} + 5°8 |Ditto. Kantore) (2.2. a-op- 57 15 | 2 23] 71 36:3} 71 48:1} —11°8 |Ditto, and gneiss. Alford). cp cecceeur> 57 14| 245) 71 45:4] 71 49-7] — 4:3 |Gneiss. Braemar ......... 57 01 8 25 | 71 30°8| 71 46:5} —15°7 |Ditto. {Pitlochry ......... 56 42 | 3 43 | 71 34:8] 71 38:3] — 3:5 |Mica schist and gneiss. Dalwhinnie ...... 56 56 | 4 17] 71 39:0} 71 49:0} —100 |Gneiss. uarbertie st isac 0 56 02 3 49 | 71 33°0| 71 17°38} +15:2 |Coal. Ardrossan ......... 55 89 | 4 47 | 71 145; 71 11:3) + 3:2 |Ditto. Port Askeg ...... 55 52 6 08 | 71 14:6} 71 26:2} -—11°6 |Mica schist. Bridgend ......... 55 48] 6 16 | 71 16:0} 71 248) — 88 Port Ellen......... 55 40] 6 10] 71 05:2] 71 20:1} —14°9 |Ditto. + Determined by astronomical observations. + Obtained through the kindness of Colonel James. ON THE MAGNETIC SURVEY OF SCOTLAND. 175 TaBieE VI. (continued.) Observed] Dip cal- | Observed i Dip re- | culated | minus Geological character of Station. ats | HOug aged to | by least | calculated % station. epoch. | squares.| Dip. ° / ° / a Tobermorie ...... 56 39 | 6 02] 72 47-9| 71 50-1| +57°8 |Trap. Glenmorven ...... 56 88 | 5 58 | 72 03:2) 71 49:2} +14:0 |Ditto. {Balmacarra ...... 57 17-| 5 39 | 72 13:8] 72 7-9} + 5‘9 |Gneiss associated with quartz and Old Red sandstone. tKyleakin ......... 57 16 | 5 44] 72 11:7| 72 7:9} + 3:8 |Old Red sandstone. Broadford ......... 57 15| 551] 72 168| 72 8-0} + 8:8 |Trap and lias. POLiEl 2,1... 00505. 57 26 | 6 12} 72 02:3) 72 15°8| —13°5 |Oolite and trap. Stornoway......... 58 15 | 6 23 | 72 33:7| 72 42:3} — 86 |Gneiss. *Callinish ......... 58 10 | 6 44 | 72 35:2} 72 41°6| — 6:4 |Ditto. PGFOSS, © S.0..c0055%.| 58 29] 617 | 72 50°2| 72.491} + 1:1 |Ditto. Loch Inver ...... 58 10 | 5 12 | 72 36:9] 72 33:1) + 3°8 |Ditto. [mary limestone. WUENESS: css: ese: 58 34 | 4 44 | 72 51°3] 72 43:1) + 8:2 |Ditto, associated with pri- SEER fois coves ees 58 35 | 3 82 | 72 34:0] 72 37°0| — 3:0 \Old Red sandstone. {Stromness......... 58 57 | 3 16 | 72 46:8] 72 47-1| — 0-3 |Ditto. RENWICK: ..... 010005 60 09 1 08 | 73 13:2} 73 141} — 0°9 |Ditto. irkwall ...dsis- 58 59 | 2 58 | 72 42:2) 72 46:6} — 4:4 |Ditto. AVG a ae 58 25 | 3 05 | 72 40:8) 72 29:2} +11°6 |Ditto. RAGUNDIG fae ss. éeains 57 58 | 3 58 | 72 26:3] 72 19:9) + 6:4 Oolite and Old Red sandstone. Dingwall ......... 57 84 | 4 25 | 72 25°8| 72 09°7| +16:1 (Old Red sandstone. + Obtained through the kindness of Colonel James. * Obtained through the kindness of Mr. Stanford, Charing Cross. Let us now divide the stations according to their geological character into two groups, the first group comprising the unstratified rocks, trap, and granite; and the second every other formation. We shall find that there are thirteen stations, including Tobermorie, in the former, and forty-one stations in the latter group. The sum of the squares of the differences between the observed and cal- culated dip for the thirteen stations is 43942, and, consequently, the mean probable error is 12’°9. If we exclude Tobermorie, these numbers are 1053'4, 66. For the group of forty-one stations we have the sum of squares=2486''1, and the mean probable error=5'3. We thus see that, whether we include Tobermorie or leave it out, the mean probable error of dip for those stations in the neighbourhood of igneous rocks is greater than for those where the formations are of a stratified description. Division I].—Total Force. These observations were taken by two different methods. 1. Method of deflections and vibrations—The instruments here used, and the method of observation, are already so well known, that it is unnecessary to describe them. Full details regarding these will be found in the Ad- miralty Manual of Scientific Inquiry, 3rd edit., 1859. By means of deflec- . m . . tions, , or the ratio between the magnetic moment of the magnet used and the earth’s horizontal force at any station, is obtained, and by means of vibrations we obtain mX or the product of the same quantities, Haying 176 REPORT—1859. thus obtained both = and m X, either of the quantities m, X may now be found. The earth’s horizontal force for any station being thus found, we have only to divide it by the cosine of the observed dip at the station taken at the same time, in order to find the total magnetic force. The following observations with the instrument used in the survey were made at Kew as a base station. Taste VII. Total Magnetic Force obtained by the Survey Unifilar. Date of observation, Total force BAU PO Sele eiiaye'steleies gi bye oy ett hei Re wa eee SA ee LE oi yee AR te ato lo das Sisal eee oS vs eae Octs, Vas ets ese ROWS ete oe ar OBES Pegi 5) a ke GA Pe A Oe ER DR Se me 10°301 1858. AUUMG uO teers interes BP] ewuere eistoussoy sek beauaegeh use COL OD RUM NEES re Pee cand aus Yate 218 she cioseUleie ahd Seperate 10°291 Ne arte SRE ee cist ate cedeb eee eee cee LOZ UR Seay Tee: Oe, Sage Ee ARE cee teete a ecient 10°304 Mean’ 78-*-sce ero 10°295 We may without error regard this mean result as the value in British units of the total magnetic force given by the instrument used in the survey at Kew Observatory, and corresponding to the epoch Ist January, 1858. The following series of observations made by another equally reliable in- strument, also at Kew, affords perhaps a still more reliable determi- nation. Taste VIII. Total Magnetic Force obtained by the Kew Unifilar. Date of observation, Total force, monthly means. Reprised is. BO) ae aes BREW yo ciety 10°3025 May shore pindnis a aisichsy areieetereneys 10°3080 UU Oats GP GLomorEniow incase cere ac HOGG cos atin L 10-300 NLT 2 Sais ieta sia! Od, 5 da © dain BAAS 5 Un eee ae ee 10°306 PUEEIES EN OW tees aces P aia s rade 10°296 v NS) yt RA eee Ee ney Srercyaheho Nols aiectece sgereneicte ete 10°291 May SSS SUE ae 5 cofohe, Fis Rea 10°3075 oD VERE S Sah a tela, sake sateen Siri, wh Sakchertnie 'aje sixes sve ea ore. oe 10°280 DULY che ose ali ea IIMS Ces one! koshe x &ejayenene aye 10°296 AD OSG gc: ith aes RIC AS chabiwes' 0500's bias ie 10°302 Septeniber 45 AR eR ee. ws cc eRe ce 10°2875 October eo: 0 aes tation. care wd oon eee 10°317 Noveurier s. c.c Some ited Bieawlens wince ta Benepe 10°301 Total force, January 1858, most probable value.... 10°299 ON THE MAGNETIC SURVEY OF SCOTLAND. 177 ‘It will be seen how nearly this value coincides with that given by the Scotch survey instrument. No correction of any kind has been applied to the observed values of total force at the different stations. At some of the stations vibrations only were taken. In such cases, it is necessary to know the moment of the magnet at the time of observation, in order to eliminate it from the product m X. This may easily be found; for every complete observation gives us a value of m, as well as of X. These values of m will be found to vary with the time, because the magnet is gradually losing magnetism, and in consequence its moment is slowly diminishing. If, therefore, we combine these values together, each year separately, by the method of least squares, we shall be enabled to express the magnetic moment in terms of the time. We have used this method to - find the value of X in those cases in which vibrations alone were taken; but for those in which both vibrations and deflections were observed, X has been determined by means of the two equations thereby furnished. In the following Table are exhibited the values of X obtained by both these methods, and also the value of the total force for the different stations obtained from the observed values of horizontal force and dip, by means of the formula— Tasie IX. Greenwich wt Greenwich F mean time| 7% | mean time | Calculated) Total Station. Date. mX. of ob- x of ob- _|value of m. x. force, servation. servation. 1857. h m h m Makerstoun ...... Aug. = SZAS ht sete tee Nata ceriee Wittman ceetees 34620} 10548 AUT aie sy dues 5| 1°7225 1 Op.) 143882} 2 4pm 7 Rene | 1 arene aaee ee 14389| 2 4 0 | proree 34604) 10/505 Dumfries ......... A nee i! 22 Se peas 49777 | 34714) 10519 : 55 A.M. - 44 eee Se apeey 14460} 044 = | footer 4424) 10523 re A | poe Gr AT KO Ye ek FO DT” Sele 49767 | 34381) 10°519 22] 1:7000 O 4pm.)}-14561} 059 | ou... 34171} 10548 25] 1:7061 6 11 NAAOS) i feer Dt © us ee 3°4310} 10°595 Helensburgh...... 28} 1:6662 1 40 W14846))/ Ola. © “lr ee 33500} 10-538 Lochgoilhead ... 29) 1:6805 SOE - OE Atl eee tee 49735 | 33789) 10-531 Ardrishaig......... Sept. 4] 1:6740 417 7) els (a ee ae 33677 | 10:575 Oban........ Oa 7| 1:6653 | 11 28 as.) 14829] 10 385 4.m) ......... 3:3511| 10-560 Corpach ......... 8| 1-6541 2 25 pm.) 14946 | 1 41 pat) ......... 3°3267| 10-702 Fort Augustus ... 9| 1-6312 Sette | raeeeea lin oceans 2 : Inverness ......... 11 | 16255 Le fit P| PLAID RAO St Fe ere 16319 4°36) 2 (CHDL26 i SULOS? © | 9 ee: 1-6320 1 16318 3 hal pe etiam Mier ee 1:6329 (0 ee? Sinaia ics [509/53 i Bh ees ae el 16520 1 Oe Ks See ct £20 a 0 Bs : 16440 | 10 20am.) 14943; 285 | o.ch... 4} 1:6657 Die AD PMNs sont lleeweesesetek 16521. | 11 19 a.m.) 14924] 10 34 4m.) ......... 5 ATE ia Gaede onan | 14869" 3 Opa! See OTe as 8 28 SS ae Total force= horizontal force psec kee nee cosine dip 178 REPORT—1859. Taste IX. (continued.) Geceamacl| Grenwich : ep : mean time ms | mean time |Calculate ota Station. pete. mK. of ob- X* | of ob- |valueof m. zs force. servation. servation. 1858. hm fe i. 5 Makerstoun Rule ely Pe te.te tal esc esceyl 14080 56 A.M. = APO: : 2 As tere Pal tea aie 14079 | O 42 pm. \ A87q0 42:2626| 105% Edinburgh 9), 1:66PA> | 8 43 Eat) sces.-cll os “ It 10°673 10-668 —"005 atiior eases cate ters as ens 16 10°576 10°596 +°020 Peterhead ..........5.05.08: 17 10°540 10582 +7042 Aberdeen ..........%:si2323 19 10°567 10°543 —*024 KntOre . uc... scusckeasodde 21 10°610 107550 —'060 Alford yeas; acc .aeoeetseer aa 22 10°594 10-599 +:005 Braemar ..........écssc4a¢ 24 10°564 10°587 +023 we EPItlOGHTY, G.s0.de0aos es caes 28 10°551 10°535 —-016 LT tit oaceoodon dees sacbos- Oct. 1 | 410541 10°552 +011 dmb UGE bee scars eesse ee 5 10522 10°536 +014 * Altered the western Y of the lifter before taking this observation. Again at Oban. + Tightened screws before this observation. It appears from this Table, that, considering the results obtained by the me- thod of vibrations as standards with which to compare those obtained by Dr. Lloyd’s process, the latter are found to. differ in several instances considerably from the former, sometimes in a positive and sometimes in a negative di- rection. Proceeding now to the observations of 1858, I find that these were taken with the face of the deflected needle to the west. They are therefore comparable with the five observations taken at Kew during June 1858. The mean of these five observations gives 10°219 as the value of the total force at Kew. This is ‘08 less than the probable value; so that we ought to add this amount to all the observations taken by this process during 1858. We thus obtain, as before, the following table, in which the results of the two methods for 1858 are compared together :— — ON THE MAGNETIC SURVEY OF SCOTLAND. 183 TasLe XIV. Total force (1) By | (2) By the Station. Date. | Dr.Lloyd’s | method of | (2)—(1) method. | vibrations. 1858. PRTUOSSAIN cpcses ecsenttos.- July 12 10°614 10°621 +°007 BOK ASkee FiF..18 ie 16 10°714 10°655 —'059 Brrdpend ; pt isetesereceste.: 19 10°703 13°675 —°028 Tobermorie ............04- 24 10°799 10'661 —'138 Glenmorven ..........00065 26 10°754 10°899 +°145 IRIIIGCAITA vcsesietcocsses 28 10°692 10°634 —°058 Weyleakin ..5t503..03..3655. 29 10°672 10°636 —'036 Broadford .....:........008 30 10°693 10°682 — 011 BRortree c.citciscs tisseeees: 30 10°636 10°605 —'031 BHORUGWAY,...0s0c0ccscscen.- Aug. 5 10°727 10°689 —038 RGHERNINIL > vtciduce rege sascas 10 10°741 10°666 —*075 MOTONS rectors sti ssceieetcccets 1l 10°759 10°742 —'017 Loch Inver ...<....:..00% 16 10°619 10°512 — 107 16 10°636 10°512 —'124 DIGETESS):354.s0wsFascectesees 18 10°743 10°697 —*046 AMROMIES Os acces case sess scackes « 23 10°684 10°674 —'010 MME WiIC Rens disPacscveccecees 30 10°716 10°738 +-022 Kirkwall siscisccdiecccssds 31 10°727 10°721 —'006 NE, cw cas poseecaceatet Sept. 4 10°720 10°700 —'020 Golépie. ..cicccccvesdscsesees vl 10°708 10°692 —'016 Be wall 6. ..ctis.20he0xi0~ 9 10°696 10°632 —‘064 By this Table we see that the constant which suited the observations taken at Kew in June 1858 does not suit those taken in Scotland a month or two afterwards, for, when applied to them, it makes the resulting force too great. The instrument must therefore have changed its constant between June and July in such a manner, that, had it been observed at Kew in July, it would have given a larger reading than it gave in June. This agrees with what we inferred from the observations of Table XII. taken at Kew with the face of the deflected needle to the east, viz. that a rise in the readings must have taken place at some time between January and November 1858. To con- clude,—in this case at least, the results obtained by Dr. Lloyd’s method do not bear comparison in accuracy with those determined by means of the method of vibrations. I have therefore made no use of the former in deducing ge- neral results. Division Il].—Deeclination. During the first year (1857) the Declination observations were made in the following manner. A collimator magnet was employed, the division on the glass scale of which corresponding to the magnetic axis was first accu- rately determined. Great care was taken that the collimator scale should not be touched, or its position with reference to the magnet in any way altered*. * There is every reason to believe that this care was successful in securing a fixed position of the magnetic axis with reference to the scale. From a determination at Kew before the commencement of the first year’s survey, 49°7 on the scale denoted the magnetic axis. Be- 184 REPORT—1859. An altitude and azimuth instrument by Cary, on a tripod firmly placed, was turned until the division on the glass scale of the magnet corresponding to the magnetic axis coincided with the vertical wire of the telescope, and the azimuth circle was then read. The altitude and azimuth instrument was then turned towards the sun, the time at which his centre crossed the middle wire was found by a chronometer, whose error and rate were known, and the read- ing of the azimuth circle was noted. The latitude and longitude of the place and the time of observation being supposed to be known, the astronomical azimuth of the sun at the moment of observation is given by a well-known formula. The difference between the readings of the azimuth circle for the sun’s centre and the magnetic axis enables us then at once to determine the magnetic declination. The altitude and azimuth instrument was often allowed to remain in position for some hours, during which time occasional readings of the magnetic axis were taken, and at the same time the azimuth of some fixed object was read occasionally, in order to see if the tripod-stand had shifted. The silk thread by which the magnet was suspended was carefully kept as free from torsion as possible, and the amount of torsion was moreover examined and eliminated from time to time. The amounts occasionally found to be present were always of such trifling consequence that no correction on their account has been applied to the observations. The chronometer used was a pocket instrument by Arnold and Dent, No. 5155. Its rate appears to have been somewhat irregular, owing probably to the motion it received in travelling. At almost every station, however, altitudes of the sun were taken, by which the correct time, and consequently also the error of the instrument, were determined. For one or two stations no altitudes were taken, and consequently no chro- nometer error determined. Here the following method was pursued. A correction was applied to the last determined chronometer error, depending upon the time that had elapsed since, and on the most probable chronometer rate. The chronometer error so corrected was used in the azimuth observation of the station whose altitude observation was wanting. During the years 1858 and 1859 self-recording magnetometers were con- tinuously in operation at Kew Observatory, by means of which the magnetic declination at any moment might be determined. ‘The traces furnished by the declination magnetometer have been reduced at General Sabine’s office at Woolwich, and the hourly means of the declination, free from disturbance, for every month of both those years have been determined. This enables us to say with great accuracy what correction ought to be applied to a declina- tion observation taken at Kew at any hour of any month of any year near this date, in order to reduce it to the 3lst of December (mean of all the hours) of the same year in which it was taken. Presuming that these corrections are also applicable to Scotland, and to 1857, they have been used in reducing the observations of declination taken in that year to the epoch of January 1, 1858. In reducing those taken in 1858 a somewhat different method has been pursued. During that year the Kew magnetometers, as already mentioned, were in operation. Suppose that we take the mean of all the hours of January 1858, freed from disturbance, as fore the second year’s suryey its position had changed to 49-0 (an inconsiderable difference). At Thurso, on August 23, 1858, the magnet was observed erect and inverted, and 49-0 was still found to denote the axis. At Lerwick, the next station after Thurso, the glass scale was wiped, after which the axis appears to have changed; but, as in every observation after- wards the magnet was viewed both erect and inverted, this shifting of the axis was of littl consequence, . ON THE MAGNETIC SURVEY OF SCOTLAND. 185 representing approximately the declination at the epoch of January 1, 1858. It will not do so exactly, because it will correspond to the middle and not to the beginning of January ; but the difference will be so trifling, that we may suppose the correspondence to be exact without further refinement. Now, by means of the traces of the magnetograph we can find the difference between the declination at Kew at any moment of 1858 and that corre- sponding to the epoch of January 1, 1858, as above defined. And this we can do even if a considerable magnetic disturbance be going on at the mo- ment we fix upon for comparison with the epoch, because this disturbance is registered by the magnetograph, and it may therefore be measured and allowed for. Now, the moment at which the needle was observed at any station in Scot- land in the year 1858 has been recorded ; if, therefore, we suppose the same magnetic changes to take place simultaneously in Scotland and at Kew, the indications of the Kew magnetograph will afford us the means of reducing accurately the observations of declination taken in Scotland in 1858 to our epoch January 1, 1858. This method has been pursued with these obser- vations. The following Table exhibits the most probable value of the absolute declination at Kew corresponding to lst January, 1858, the method of reduc- tion to epoch being that now mentioned :— TaBLe XV. Declination. Time of Needle Date. : Reduced Observation. used. Observed. | to epoch 1 Jan. 1858. 1858. h m lil an. 5/10 5S a.m. Survey 21 57°5 21 563 5) 2 10 pM. 7 22 30 Feb, 4| 413 ,, a 21 58:6 5) 10 31 a.m. +" 21 54:4 21 54:8 23) 115 P.M. + 21 59°8 Mar. 1] 11 22 a.m. re 22 23 2} 2 24P.MmM 22 8:0 4| 10 34 aM. f a1 56-2 (| 22 960 5| 2 6 P.M. rp 22 3:3 April 26) 1 7 ; 22 3:0 11 46 am ft 21 59.5} ARES May 26) 0 4pm 22° 0°2 : 26| “4.15 ., 4 21 59.3} ae Aug, (13) 3,9. 4, Kew 21 Souk 21 556 Sept. 16] 321 ,, i 21 54-7 | 21 57:1 Oct. (14) 3 32 ,; a 21 54:3 21 551 1859. Sept. 27| 4 43 _,, ie 21 443 | 21 53-4 Oct. 31] 11 28 a.m. ‘ 21 486 | 21 57:1 Noy. 18) 4 7 Pm 21 46:4 : 19} 029 , . a1 48-0 f| 2! 566 Blech sk17). ,! i 21 45:8 | 21 54:9 Mean declination, Jan. 1, 1858} 21 55:9 eee 186 REPORT—1859. The following Table exhibits the declinations taken during the first year’s survey; reduced to the epoch by the method already mentioned :— Taste XVI. DECLINATIONS—1857. Declination. Gréeci Wich | Se eee Station. Date. mean time Reduced to of observation.| Observed. epoch 1 Jan. 1858. 1857. | hm ; Acai Makerstoun ......seseeee Aug. 10| 7 54 a.m. 23 52°5 23 56-1 Melrose ......seceeeeeees wets 12| 5 44 P.M. 24 28°0 24 27°4 Edinburgh.........ce.00 ae 13) 412 ,, 24 59-2 24 55°) 13 1 eS a 25 4°5 24 56:0 Gretna cersssecdevsssecdense 15) 1 23 P.M. 23 41:2 23 32:7 Dumfries ..... San dedeae wee 17| 9 8a.o. 24 46:3 24 48-2 17/10 20 _,, 24 48-7 | 24 46-4 17 1 23 p.m. 24 55:0 24 46°5 Newton Stewart ......... USileabe Oise. 25 11°5 25 10:4 Stranraer .....ccoesseceness 20| 9 48 a.m. 25 37:2 25 37°2 20| 1018 ,, 25 40-2 | 25 38-0 20 1 18 p.m. 25 48:2 25 39°7 AVE Peas coattesenssutv ess sins 22} 9 9am. 25 24-7 25 26°6 22) LORS) @;; 25 24-7 | 25 23°9 Glasgow..e.sscesecveeceevece 24,19 SY 5; 25 28:3 25 28°8 24/10 30 ,, 25 30°2 25) 2753) ' 24) 2 31 pM. 25 34°7 25 27°5 Brisbane dicceccsiecsccaces PAN CMG So 2520-7 25 14°2 Cumbray ........ “Bupttasos O78 el Alike a 25 44°6 25 36°5 Helensburgh ..+....0ssesee 28 | 11 10 a.m 25 43°8 25 38°7 28) 3 53pm 25 44°7 25 40°6 Lochgoilhead ............ 29 A ABI iy 25 56:2 2p, pe) Campbelton .........06 | Sept. 2] 7 38 a.m 26 192 26 23°5 Ardrishaig .....sssesseeee Bi 4} 2 45 p.m 26 34:8 26 29°8 Ale See oe 26 30:5 | 26 29-9 Oban ...... weoumuestaterese ns 7| 9 42am 26 11:0 26 11°6 Corpach..:...:.s5.05 eacpac: 8: 9 oo.a 26 22:3 26 21:9 Fort Augustus .........++ 9) 6 22 P.M 26 6:0 26 6:0 al a a (7A 26 4:3 26 ene INVERNESS: sxcceocsy-secce0es 14] 9 22 a.m, 25 56°5 25 58°7 Elgin. finest sbasaens * l4{ 4 32 pM. 25 8:2 25 67 14f 16 Ag: “S 2 68 | 25 71 Bante sddvtsractetaceccseccees 16 | 10 16 a.m. 25 18-7 25 17°4 Peterhead ........ atti staond 17| 4 57 p.m. 24 34:2 24 33°4 Aberdeen .....4.sceeceeee ie pias be 24 37:5 24 29°5 19) 4002 55 24 34:3 24 32:2 Alford necesesacas Messicasses CPOE TIAL ae 24 39°3 24 35°7 22 (BOL v4; 24 38:2 24 35°6 Braemar | decsesestesaseeses 24| 9 27 a.m 25 7:2 25 87 ey 30°; 25127 | 25 88 Pitlochty eevanseneseeess crn: Oe} | Hee tole Uleuep 25 18:2 25 23:0 Dalwhinnie .........0.00 DON Hi sO: » 4s 25 50-2 25 54:0 Zonet sos) y; 25 49-7 25 54°5 Edinburgh,....+.s....e0ese| Oct. 5] 11 45 a.m. 24 59:2 24 53°6 5| 3 54pm 25 2:8 25 0:2 ON THE MAGNETIC SURVEY OF SCOTLAND. 187 In 1858 the declination was observed by means of an instrument of a dif- ferent kind. This was invented by Dr. Lloyd, and it is described by him in the Proceedings of the Royal Irish Academy, January 11, 1858. In this instrument the telescope is horizontal, and there is a mirror by which the sun may be reflected into the telescope, and its azimuth determined. The mirror being adapted to the telescope by which the scale of the magnets is observed, the same horizontal circle is made to serve for determining everything, and thus the theodolite and additional tripod are dispensed with, while the alti- tudes of the sun are determined by means of a small sextant and artificial horizon. A considerable reduction in the observer’s travelling equipment is thus obtained. In Dr. Lloyd’s instrument three adjustments are required. 1. The axis of the mirror must be horizontal. This is tested by a small riding level. 2. The plane of the mirror must be parallel to the axis. Should this not be exactly the case, the error is eliminated by first observing, then reversing the axle in its Ys, observing again, and taking a mean of the two readings. 3. The line of collimation of the telescope must be perpendicular to the axis of the mirror. The error produced by want of a perfect adjustment of this nature may be got rid of by viewing the sun (1°) direct, or facing the south, (2°) backwards, or facing the north. For, let 6 denote the error of azimuth in a direct observation, 6! the same in a back observation ; then it may be shown that 3=+C sin’ $ alt. cos alt. y==C cos” 3 alt. cos alt. ’ where C is a constant quantity. Hence if A, B denote the readings of the circle in the fore and back obser- vations, we have in the fore observation 6= +{180°—(A—B)} sin’ 4 alt., the sign of 6 being such that the truth lies between the results given by the two observations. Before the commencement of the second year’s survey, the axis of the mirror had been accurately adjusted so as to be at right angles to the line of collimation of the telescope, but on July 20, at Bridgend, the axis was found to be very much out. A plumb line was suspended, which was viewed by direct vision, and backwards by reflection. When viewed by direct vision, the circle reading was 348° 18', while by back reflection it was 350° 20’, the angle of inclination of the mirror to the horizon in the back observation being about 2 \e) 80°; the formula 122’=C So 10 cos 20° sequence of this, it has been thought advisable to reject all the observations before Bridgend. At Bridgend the mirror was readjusted, and for all the ob- servations afterwards, with the exception of two, the sun was observed both by direct and by back reflection. The following Table exhibits the values of é co C at the various stations, where both fore and back observations were taken :— gives C=118',—a large amount. Incon- 188 REPORT—1859, Taste XVII. Station. 6 C GlenmMorven .......sereeseeees 4143 448 Balmacarra, cssssseeee Seaesyas + 2°9 35°8 Kyleakin cs.cccsesccccscveeess + 31 41°3 StOrnOWAY...ccerecseeee Acoreie| Pe was pia 46:0 + 1:3 35°4 Callinish ....... Waucoscensecs + 1:2 41°2 TOSSisevescesses os sponges Reese + 2:5 39°9 Tioch INVeEr. “sencevscesssocees + 43 47°2 DUIHESS ...cccccevescncecveceses + 27 40°1 BUTS Pccsusseessursctee Senge, + 3:2 35'3 MCL WICK sewcesacsstcarssxecyes + 10 41°2 Wick ...... nrpecas + 4:0 430 + 2:0 36°9 OlSpleis-.preazecevaressaretwae + 13 37'5 We see from this Table that though C (which is equal to twice the angle by which the mirror is out in adjustment), as exhibited in the third column, is somewhat large, yet the correction to be applied to the actual observations, denoted by 6, is generally very small, the only exception being Glenmorven, where the altitude of the sun was high at the time of the azimuth observation. It has been mentioned that there were two stations after Bridgend at which no back observations were taken. One of these was Port Ellen, the next station after Bridgend, but as the altitude of the sun was high when the azi- muth observation was taken there, it has not been thought advisable to apply a correction proceeding upon an assumed value of C. ‘The other station was Kirkwall, which occurs in point of time between Lerwick and Wick. The value of C for Lerwick is 41/2, and for Wick it is 43"0. If we assume the mean of these, or 42!*1 as the value for Kirkwall, we find d= -+2'2, which value has accordingly been adopted. Table XVIII. (p. 189) exhibits the declinations for 1858, corrected for error of mirror, and reduced to 1st January, 1858. If we now take all the declinations, with the exception of that for Glen- morven, which seems to be influenced by local attraction, we obtain by the method of least squares u, or the angle which the isogonic lines make with the meridian =—20° 58'3, or their direction is from N. 20° 58':3 E. to S. 20° 58/3 W.; r, or the increase of the declination in a direction per- pendicular to the isogonic lines,=1'-465 for each geographical mile ; and d, or the declination at the central station, lat. 56° 54’ N., long. 4° 14’ W.= 25°53!:-6. The isogonic lines are exhibited in a map (Plate 7) appended to this report. In Table XIX. (page 190) the observed and calculated declinations are compared together. If we now divide the stations, as before, into two groups, the first comprising trap and granite, and the second every other formation, we shall find the mean probable error for the former group= 24'S, and that for the latter=11"1. If we examine Tables VI., XI., XIX., in which the difference between the observed and calculated magnetic elements is given for the different stations arranged in the order of observation, we shall, I think, perceive that stations similarly affected with regard to sign are in many cases grouped together. But, from the principle of arrangement adopted, the members of any such group denote stations at which the observations were consecutive with respect to time; so that such stations cannot be very far apart with respect to geogra- phical position. ON THE MAGNETIC SURVEY OF SCOTLAND. Tasie XVIII. Greenwich 3 Mean Time Station. Date. Gr ohedive: tion. 1858. hm Glenmorven ...... eeeeee(July 26..| 0 32 pm 26..12 16 ,, Balmacarra ............ 28..| 8 47 a.m 28..19 53 ,, 28..|0 3pm Kyleakin ....eesseeeeee Aes ade 29 Di 2h 59 0s) Goh a: Stornoway .......+....-.| Aug, 5..15 56 ,, A Be ae Bir | 6410), 6..|6 0 ” ' 6..|617 ,, 6..16 22 ,, NEOELTIDIS alsiais' siete a'c.c'e,s,0 ete || PAGES) a 9..|3 28 ,, Oizi| 3 30 ac 9..(5 29 ,, 9..15 35 ,, Qi7|| Oe 2s: 9s OPE Grae - 55 MIENIEAMnreictetale: sivicfeva.e.s\6: s\e/e's 11../ 9 ll am 11../10 26 ,, 11../11 30 ,, 11..}0 9PM Loch Inyer....,-+ese0.0. 16..} 9 54 am FEPSOML: 16s-}ay'.. 16../11 54 ,, 16..| 0 21 pu Durness ..... afetaterehe aicierete WSee| oe au sy 18c| 406), tess) 4033170 TRS BE ic, PDVSO rors weenie wien ose 23..| 9 4] am Desies | weed ees. 23..| 0 45 p.m 2d s=| OPO ss BRRIGTEIL S454 5 ice" clo'eie es 30..| 8 12 a.m 302.) 8-30..., 30../10 2 ,, 30../10 57 ,, SMe | LID Te. 5s S 30..| 0 31 p.m Kirkwall... sss. " alee er Ay) map Slical OD Mente WICK, (2 pf oraici0 cs 01s aiefalebis's) =e Sept. 4../10 19 a.m -j11 41 =«,, 4..| 0 45 p.m 4..|3 56 ,, 4..| 4°43..,, Golspie, -..sseseeecccces hee) 4°33. x eel 250... distal AQ i, Merd\ (On Liv. iy Observed. to eo wmnnnre NSW TORN SAGSNNH IS to ~T Nmore TDSODHDHHDDHASCWHATSONNHUINNASSMWUG i) x nr pote ow to lor} ow rs np a Oe EG Oe CC Ten te CaCl ib AAANW AR SENDHEAWH HHA to o ee oor Declination. Corrected for error of mirror. 28 28 27 27 27 27 27 27 27 27 27 27 27 27 28 28 28 28 28 28 28 28 28 28 28 27 27 27 27 28°9 303 27-1 28°1 35°8 50°5 48-7 49°6 56°5 Nnonn— oN NN WOH ee CUR OR ST Ot COO SO OS SF OT 00 0 0 09 0 ~AWHDHHOEAHDOROMH EE EEE ADDOSHE EAR 57°4 — eo WYSSBOOOH ASLOONAKRSD 189 Reduced to 1 Jan. 1858. 28 28 27 27 27 27 27 27 27 27 27 27 28 27 28 28 28 28 28 28 28 28 28 28 28 27 27 27 27 27 27 27 tN bd et NWN NH eee i 4S 1S 6S eet ed re SIO 9 Ne CDRS Nicer Ge RSA ies SF ABANIKROTH SH WONDER RHR ONE Sie eS Coes Oo ane RIAD RREH OG: te 190 REPORT—1859. Such groups of stations will in fact represent districts, some of them of considerable extent, which thus appear to be similarly affected by local attraction. The observations are probably insufficient to enable us to determine the disposition of this attractive matter; but there is one very marked case to which I may be permitted to refer. If we examine Tables VI. and XI. we shall find that the stations in the Island of Isla have their dip diminished and their total force increased by local attraction. On the other hand, the Mull stations have both dip and total force increased, while those in Skye have their dip increased and their total force diminished. Such a state of things might be brought about by a powerful source of attraction for the north pole of the needle situated a little to the south of the Mull stations at a considerable depth below the surface. This supposition derives confirmation from the fact that the errors due to local attraction are exceedingly large in Mull. TasiLe XIX. Observed Station. Observed. |Calculated.| minus calculated. Makerstoun ........scscseseseee: 23 561 | 238549 | +4032 IWECIFOSE Mc dcote tessa tices siacnsas 24 27-4 24 02-4 +25:0 Hdinbuaphy<: hir...fereecss cases 24 56-2 24 36-4 +198 Grete are ss. 2 Ree k 23 32:7 23 58:3 —25°6 DMpnfries so. gee eects vanes 24 47:0 24 26-4 +20:6 Newton Stewart ...........000. 25 10-4 25 02:7 +077 Stranraer . 2.622858" oc crac 25 38:3 25 27-7 +106 PANNE Meee ase mreaoaches Teeigt ass 25 25:2 25 26:3 —O11 Gilakoowe = is... des.ckaesetweres. 25 27:9 25 22:5 +054 MBRIGhaTIG: /..22 ts ucdeens se soa eee 25 14:2 25 48:3 —341 Cimbyayy ons. te secs ages ooasiisigy on 25 36:5 | 25 478 —11:3 Helensburgh .....:.....-.2s-e00 25 39:6 25 48:3 —08:7 Lochgoilhead ...............45 25 52-1 26 00:7 — 08-6 Campbeltown .........0.:00ee 26 23:5 | 26 140 +09°5 pAmdtsbiaias Seay. ois cee ucge 26 29:8 26 22:0 +07:8 (0 | TOR iGee ee ae nocehcme mente ree 26 116 26 342 —226 Carpiach’, . 55. -fedkoas chine namatnuge 26 21:9 | 26 33:1 —11:2 Fort Augustus .............0065 26 41 26 20°7 —166 Inpvernésp 21.0: Abe eh ld edhe 25 58°7 26 08°8 —101 Bight Ue. bese tne rates 25 69 | 25376 | —30-7 ESAT Ege cia ioc Ae alee Reka gees 25 17-4 25 02:0 +154 Peterhead 24 33-4 24 25:0 + 84 Aberdeen 24 308 94 25-7 +051 WT 230 Ne ee ie 24 35:7 24 58:5 —22'8 Braman /52.ce here aeeen 25. 58:7 25 20-4 Sy Pitlophry: 22 See seities deaxenss 25 23:0 25 24-1 —O1+1 DalyhinniesAefe esses ees 25 54-2 25 57-4 — 03:2 Glenmorven: 2.6.6.8 .0 tens anee 28 21:1 27 03:2 +779 Balmracarral sctseteee cc: Mesias 27 32:5 27 08-6 +23°9 iReylealainiy :v.siactecc teas scar pan 27 50-4 27 122 +88-2 Sfommowayei..heawetdterescw detee 27 561 28 09-1 —13:0 Callinishis) ese atheies hae 28 87 28 21-6 —12:9 Grosaigiin-.-. mieten shea 28 25-4 28 12:3 +13-1 Loe Intyer” isicnedesscser scans 27 11:2 27 15:9 —04-7 DiUrnesyt nas. -peceecdean cece me anes 27 29-6 27 68:0 +21°6 Miura ee cel ance ett ee eae 26 30:3 26 16°5 +13:8 Tierwidkes cits ace dete ateve de 25 17-5 25 30-1 —126 Karlowalll- coxsieesnaheace save es os 26 17-4 26 05:9 +115 WICK. cco ncccree re nea 26 37 | 25 52-1 +116 48 26 16:3 -01°5 (o} S, wD KS z. a>} Ww Qe se ON THE PATENT LAWS, 191 The Patent Laws.—Report of Committee on the Patent Laws. Presented by W. Farrpairn, F.R.S, Ar the meeting of the British Association at Leeds for the year 1858, a Committee was re-appointed for the purpose of taking such steps as might be necessary to render the Patent System of this country, and the funds derived from inventors, more efficient and available for the reward of the meritorious inventors and the advancement of science. Cireumstances beyond control have prevented that Committee from taking any decisive steps in furtherance of the important objects entrusted to them; but those objects have not been lost sight of. No reply has been received from the Commissioners of Patents, either to the Memorial of the Glasgow Committee of the British Association, or of the Public Meeting in Manchester ; but some of the questions referred to in those Memorials are adverted to in the Report of the Commissioners just issued. From that Report, itappears that the number of applications for patents may be estimated atabout 3000 per annum ; that of these 2000 applications not more than about 2000 proceed to the final stage of a patent; and that of the 2000 patents granted, not more than 550 are kept alive beyond three years by the first periodical payment of £50 before the expiration of that term; and the Commissioners anticipate that the fee of £100 payable at the end of the seventh year will not be paid on more than 100 of the surviving 550 patents. Should this anticipation prove correct, the payment by inventors in fees upon patents not surviving beyond one half their term of fourteen years will not be less than at the rate of £100,000 per annum as a direct tax on the inventive genius of the country, in addition to and exclusive of time, labour, and other charges and expenses. The total outlay in respect of those patents may be estimated as at least £250,000, or a quarter of a million, per annum. ‘The great work of printing and publishing iz ewtenso the specifications of patents granted under the old law, that is, from 1711 to the 1st of Oct. 1852, in number 12,977, is completed ; and the surplus funds hitherto absorbed by this object will be henceforth available for other purposes. That surplus is estimated by the Commissioners at £30,000 for the current year 1858-59, and to increase in each succeeding year at the rate of £20,000 per annum. This surplus, after providing for the current expenses, is proposed by the Commissioners to be appropriated to the following objects :— T. The erection of a Museum for the preservation and exhibition of models, of which a considerable collection already exists at Kensington. 2. The erection of suitable offices for the Commissioners, including a free library of consultation upon a more extended scale than already formed by Mr. Woodcroft. These most desirable and legitimate objects of application of the “ Inven- tors’ Fee Fund” cannot, however, be attained without the sanction of the Lords Commissioners of Her Majesty’s Treasury, and a vote of Parliament, inasmuch: as all the fees levied on Inventors are by a recent change levied in the shape of stamps, and so pass directly into the Consolidated Fund. These recommendations of the Commissioners will, it is conceived, be regarded as a most legitimate application of the funds of Inventors, and as ove to which the Parliamentary Committee of the British Association will give their aid; but your Committee think that other considerations and other claims upon the Inventors’ Fee Fund, and upon the annual surplus, whatever 192 RBPORT—1859, its probable amount, should be forthwith urged upon the Commissioners and upon Parliament. The Report of the Patent Committee of the British Association to the Leeds Meeting called prominent attention to the two following questions :— lst. Whether the present scale of payments should be maintained, or reduced, so as to leave no greater surplus than necessary for official expenses ? 2nd. If the present scale of payment be maintained, how shall the surplus be appropriated ? The Commissioners of Patents are in favour of maintaining the present scale of payments, on the ground “that any material reduction in the amount of fees would undoubtedly tend to increase the number of useless and speculative patents, in many cases taken merely for advertising pur- oses.” : Your Committee are not insensible to the force of this observation; but they beg respectfully to doubt whether this money check has any effective operation on the class of cases most requiring to be controlled, and whether the remedy is not worse than the disease, in laying an unjustifiable burden on the inventive genius of the country, and effecting a confiscation of property of its own creation. Your Committee are much struck with the fact, that the application for about 1000 patents is not prosecuted to completion, and in many cases probably not beyond the first stage; that the first periodical payment of £50 at the end of the third year is not made in respect of nearly 1500 of the 2000 patents granted ; and that the Commissioners anticipate during the ensuing year the surrender or lapsing of no less than 450 out of the 550 patents which survived the first periodical payment. It must be borne in mind that the granting of patents in this country is practically without control, no attempt having been made to interpose any of the checks urged before the Committee of the House of Lords in the Session of 1851, and provided for in the three bills of that Session, and in the Act of the subsequent Session, now the law of the land. The payment of £5 on the first application may be regarded as a registration fee: the applicant makes this payment on lodging the papers, obtaining protection and inchoate rights from the moment of his application. This was one of the cardinal features of the new system of 1852; it has been productive of the greatest benefit to inventors, especially to those of the poorer class, by enabling them to obtain inchoate rights, and to create property for them- selves by a simple record of their inventions, without publicity and the obstruction of interested opponents. This power of placing inventions on record is also resorted to in many cases by those who do not wish further to secure or appropriate to themselves property in their ideas and inventions, and which forthwith become public property. The 1500 lapsed patents must be regarded in a different light: these have cost their authors no less than £37,500 for fees and stamps as a direct taxa- tion on their inventive genius, in addition to and exclusive of other pay- ments of at least an equal amount. Of these 1500 patents, it is believed that the progress of at least 1000 might be arrested with the consent of the applicants, if the inquiry before the law officers were substantial instead of merely nominal. Thus a large use- less outlay of capital in money and time would be avoided, talents unpro- fitably employed would be directed into other channels, and the creation of legal rights would be limited and reduced exactly in proportion as the appli- cations were not proceeded with. ; LUNAR INFLUENCE ON THE TEMPERATURE OF THE AIR. 193 Your Committee conceive that the application of a portion of the funds contributed by inventors would be most properly applied to affording them this species of protection against the unprofitable expenditure of time and money: the attempt is surely worth the trial ; it would effectually check the prostitution of the patent system to the illegitimate purposes referred to by the Commissioners. The reward of the meritorious inventor in cases in which he alone of the public has failed to benefit by the fruits of his genius, and the purchase of patent rights in him of extending their terms, was referred to in the Report of the Patent Committee of the British Association at the Leeds Meeting as a legitimate appropriation of a portion of the surplus. These objects beiug satisfied, a very large surplus would remain available for the advancement of science by researches having a direct bearing on the reproductive industry of the country. And if it be thought expedient that more money should be levied on the granting of patents than necessary for the expense of the office, inventors have, it is conceived, an irresistible claim for the expenditure of that surplus upon objects bearing on their in- terests and the advancement of science. W. FAIRBAIRN. Epwarp SABINE. Aberdeen, Sept. 16, 1859. Tuomas WEBSTER. Lunar Influence on the Temperature of the Air. By J. Park Harrison, M.A. 1. Tue definite form assumed by lunar curves of mean temperature, obtained from the means of tables framed expressly for the purpose, was brought be- fore the notice of the British Association at Leeds in proof that the moon exerts an indirect, yet appreciable influence over the atmosphere of our globe*. A longer series of observations at Greenwich, extending over the period of 43 years, and embracing 520 consecutive lunations, has since been tabu- lated ; and the means of the different columns formed into another, and what may be termed for distinction’s sake, a model curve (Plate II. fig. 1). It presents, in common with those which had been already constructed for shorter periods of time, very marked characteristics. Upon turning to the Plate it will be perceived that the amount of heat signalized by the shaded portion of the curve (or all that rises above the general mean line) is considerably greater at first quarter than at any other period of the lunation, though it will also be noticed that the temperature immediately following on new moon exceeds it in height, on one day by +10 of a degree (fig.1). Upon the average, the first half of this curve, from the 2nd or 3rd day before new moon to the 3rd or 4th day before full moon, rises as much above the general mean as the remaining half falls below it. It sinks below the mean line at the period to which attention was originally drawn, * At Dublin, where attention was directed to but a small portion of the lunation, it was shown that the temperature immediately following on the moon’s first quarter was higher than the temperature of the third day before first quarter, both at Greenwich and Dublin, for the series of years subjected to examination. 859. on 194 REPORT—1859. viz. about the 3rd day before first quarter (or the 4th or 5th day of the moon’s age), and at three other noticeable points of the curve; these, as I have already stated, are (1) shortly before and (2) shortly after full moon, and (3) immediately after last quarter. In the colder half of the lunation the temperature rises at full moon, and shortly before last quarter. 2. It is not, however, only upon an average of a long series of yearly means that the proof of lunar influence depends for its establishment. All the more remarkable deviations from the calculated mean temperatures of the day, for which the past year has been distinguished, have followed the model curve in a more or less significant manner, at the seasons of excessive heat or cold above alluded to. I have elsewhere shown that this was the case in November 1858*, and in January, March, and April in the present year+ ; and it has since proved to be so in September and October, and thus the greatest amount of heat on the average of 12 lunations in 1859 displays itself according to the rule above indicated in the first half of the curve, the greatest amount of cold in the second half (see fig. 2). The mean of the means of the several columns is 51%] ; the mean of the first 14 columns 51°-9, of the remaining 14 columns 50°2. The table of mean temperatures from which this curve was formed is appended, in order to afford those who may wish to examine more minutely the nature of the influence exerted in separate lunations, an oppor- tunity of doing so. It will also serve to illustrate the method which was adopted in arranging the observations in the several lunar tables from which the curves have been obtained. 3. The popular belief in a tendency in the weather to “ clear up,” or the con- trary, at certain periods of the moon’s age—a notion which my own observations appeared to confirm—joined with a strong impression that these seasons would be found to synchronize more or less closely, according to the time of year, with the periods of greatest cold or heat in the lunation, led to the con- clusion that the rise or fall in the curves of temperature must be due to the action of terrestrial radiation, as a secondary cause ; and that the rise in tem- perature at other periods of the lunation might also possibly be attributed to the opposite state of the atmosphere when radiation upwards to the sky is stopped, more particularly in winter, by the presence of low or thick masses of cloud. This view has been much strengthened during the past year by results which were obtained from an examination of the bi-horary observa- tions of cloud taken day and night continuously for seven years (1840-47) * See Phil. Mag. for March 1859. + Whilst, according to the calculated average, the mean temperature at the end of March and beginning of April ought, in each case, to rise above and fall below the mean of the month, in 1859 this was exactly reversed. A very cold period occurred at the end of March, the mean temperature (on the 31st) being 9°:4 below the average of that day of the month for forty-three years, as determined by Mr. Glaisher. But the 3lst of March was also the third day before new moon, and the mean temperature of that day of the lunation zn March for the same number of years falls below the mean temperature of the lunar curve. So also in April, the mean temperature of the 7th day was 17°°5 in excess of the mean temperature of that day for forty-three years at Greenwich, and the mean temperature of the 15th day was 8°'3 below the average. Here the 7th day of April fell on the day of maximum tempe- rature for the lunation in 4pril or the first octant, and the 15th day of April was the second day before full moon, which is within the cold period which precedes that phase of the moon. The minimum temperature at the Toronto Observatory also in January 1859, which was ~26°'5 on the 10th day, rose on the 13th to 36°0. At Greenwich a similar rise took place from the 9th (or 3rd day before first quarter) to the 12th (or day of first quarter). On the former day the minimum temperature was 28°°5, on the latter 41°*2, and the mean tempe- ratures 33°°6 and 45°°0. There appeared to be a considerable development of electricity at all the periods of low mean temperature. (From a communication made to the London Me- teorological Society, and reported in the ‘ Athenzum.’) : 73°2 | 74:3 | 59°4 | 59°5 50°8 | 53°0 53°1 | 56°6 39:0 | 38°6 43-0 46-9 44°5 42°5 52:3 57°3 70°9 | 67°7 60°7 | 66-6 54-4 561 | 55°9 33:8 33°5 49°9 Interval. 41-2 46°6 48-4 42-4 49°8 56-4 66°5 681 54-4 55°6 33:8 27-9 49°3 a d hm 7 16 35 7 23 47 8 419 4 49 0 50 17 19 8 21 0 10 18 18 15 28 15 42 18 50 0 36 8 32 a Sk er cs. ea Gs SS Se OD See first column. 411 415 512 45°6 52-2 64:9 68:9 69-4 52°6 51:0 38-9 27-0 50-4 41-4 42:0 48:8 52°6 58°3 585 59°9 63-4 53° 50-2 38-7 22'8 49-2 [ To face p. 194. ] 2 3 Qnt 2 o,| 412 45°1 | 43°8 45°0 42°38 | 45°2 | 43:3 496 | 474 | 35°3 45°2 | 468 596 | 59°0 | 58:0 61:9 | 69:0 62:1 | 69:2 66:3 | 6971 52°6 | 54:7 36°8 | 36:3 40°2 | 35°71 23°4 | 23°9 | 30:0 48°8 | 49°9 y Mean Temperature for 43 years consists of 520 lines of figures. Lunar Table of Daily Mean Temperature in 1859, at Greenwich*. [Zo face p. 194.) AS ee SO ee Pe pe S28 od eS Py ey Sy 8 of ye oe ato | sio| s80| a86| sta | 422) 480] 1] a82] 383] .. | 980] st7| 480] 56s] 84) do] siz], | 480) ata] sir] so] ata] soa] sis 417 | 402] ... | 379) 990] 442) 445 | 449] 458) 459] .. | 430] 485) 503] 496) 426] 406) dco) ... | 469) 4o6) 415) 427) 420) 428 | 492 499 | 493] 405} 387 | 408 | 466) 535) 522) 506) 442 442) 483) 476] 452] 437 | 464] 427] 408 | 405) 454) 912) 496) 488] 496) 474 sso | ori| .. | 6s0| s29| 593] 493 | 470] ava y22| a74| 975 | 375) 982 | 399| 427] 435 | 425) soa] 456 | 498] s26| 452] 468] .. 43] 471] ... | 478) S64) 524 | 603 | 474 | 525 520 | 327| 526) 528] s03| 516] 519 | s10| 523] s98| 522] 559| 583 | 596 | 590] 580 623 | 656 653 | 635 | 60-7 | 622] 6416) ors 610 | 610 | 563] 608) 574) 573) G09] 606) 573) 54] O19] 6o7| 585] Gr9| coo] ... 22 | 660! ... | 609 | 61] 693) 700] 655 | os 757 | 752) 660] 684 | 70:7 | 732) 743 | 709 | 67-7) 665] 689) 615] 59-9] 621 | 692 675] 657} ... | 622) 64) 651) 607) 597] oar 575 | 623) 661 | 671) 689 | 594] 595 | 607) 666] 681) 694] 626) G34] 663 | Gor) ... 555 | 533 ss4| 79] s94| 560) 57:3) 591 596 | 551] 546 | 576] 518] 508] 530] ... | sia] Si4| 526] 558| 538] 526] St7| October...) 588] 674 | 620| 598) 562) S87) 565 562] 6i1| 594] 63-9 | 663) coe] 627) oa2| 581} 576) 563 | 539] 536 | 531| 566) 561] 559] 556) 510) 526| 502] S68] 363] ... November../ 368 | 333 | 321] 361 | 421) 367] 456) 426] 407] 45:3| 514) 483 | 47-2) 48:9) 503] 542) 513] 461) 385) 370] 395] 390] 386] ... | 338) 338) 389) 391| 387] 402) 351)... December... 396 | 404| ara] 447 | 397] 460] 430] 404] 997] 362)| aoa] saa] 921] 367) 479] 442] 425] 420) 992] 970/ 308)| 935 | 335]... | 335] 279] 270] 251] 228) 254) 299) 500 Meas .=|/518)| 606) su0| sro| sra| sre| se4 $05 s17)| 895) s3a)| 623] 525 | s28] .. | s21|/sr6| so8| srs | dee | 491) S05 49] 493 | soa] 003/492 | 455 | 499). Mean... 51°9 x Mea... 50°2 Nole—The several months commence from the dark jines or stops. * The Table of Daily Mean Temperature for 43 years consists of 520 lines of Ogures. Table of Moon's Phases in 1859. e > Interval. o Toterval, € Tnterval. e 10 raw WB iem, [9 om lat Saas, | Gite ar Sir | 71035 10 9am. 13 3 28 Pa 6 21 38 20 1 6 rm. 6 16 32 27 5 38 Aw. 7% 47 525 vate 1207 22 am. 6 16 26 18 11 48 Pam. 6 20 57 2% 845 ro, 8 419 1 dam. 10 7 39 ra. 61 2 ‘17:10 41 Am. 7 340 24 221 ra B 449 7:10 wm. 12 439 Am, 617 6 18 945 rat. 71 a2 26 9 27 Am. 8 050 1017 aa. 101 20am. | 62145 | 17 9 Saw, | 71940 | 25 Ads am. | 71719] 2 10 4 pate 9 489rm. | 7471) 16 9 Gro | 8 143 | 1049 rw | 7 821 | Z 710 aa 7iod7ru. | 71190 | 1017 aa, | 8 414 | 23 231ro. | 7 010) E [ao aan ra. | 7 5s3am. | 719 0/15 05am. | 8 292 | 23 3254u| Gisie | Z 945 Pm. 5 3 2) ra. 8113 134 34 ra 7uu 21 1:45 raw. 615 September...) 28 5 13 am. 44 dame 8427 12 8 31 as. 7:13 42 19:10 13 pas, 615 42 October...) 26 1 55 via. 3 831 eu. 8 320 11 11 5) rat. 7 551 19 5 42 At 6 18 50 | November...) 26 0 32 aa 2418rx, | 72147 | 10 2 Sew. | 6231 | 17 1 Gru | 7 096 | December «| 24 142 vate 214970, | 71323 | 10 51240. | G18 3 | 16 915 ex | 7 892 | * * New Moon, December 24th, at Sh, 47m. a. LUNAR INFLUENCE ON THE TEMPERATURE OF THE AIR. 195 at the Royal Observatory at Greenwich, and which were published, amongst other elaborate meteorological tables, in the volumes for those years. Out of 55 clear days, or what might be considered clear days, there enu- merated—those being considered as nearly clear on which the amount of cloud did not exceed *3—no less than 42 occurred at periods of low mean temperature in the lunation. And it is worth notice, in connexion with this fact, that during the three years (1844, 1845, and 1846), in which the late lamented Radcliffe Observer found from observations taken for the purpose, between the day of first quarter and the day after full moon, “that the moon was visible on an average 137 times on the meridian when the sun is seen only 100 times,” the Greenwich Observations of cloud show an unusual number of clear days to have occurred at that station on the three days following on first quarter, the effects of which would appear to be traceable in the curve embracing the years in question (see fig. 4:). Still further to test the point, a curve of the mean amount of cloud in November during the same seven years was formed for the purpose of com- paring the approximate amount of cloud on the different days of the moon’s age with the line of a lunar curve of mean temperature for 40 consecutive Novembers. It was hardly possible to doubt, on carefully examining the two curves thus placed in juxtaposition,—the waves of cloud being for the most part a day in advance of those of temperature,—that an intimate connexion does exist, as cause and effect, between the amount of cloud at different periods of the lunation and the temperature of the air. On the Continent, too, it was found that the results obtained by Schibler at Augsburg, from 1813 to 1828, had been examined by M. Arago and admitted to be in accordance with those arrived at by Flaugergues at Viviers, from 1808 to 1828. From a Table of the relative number of serene and clouded days at Augsburg during the above-mentioned sixteen years, M. Schiibler found (1) that clear days were more numerous at last quarter; (2) that the greatest number of clouded days occurred towards (vers) the second octant. Also in twenty-eight years at three different stations, namely at Munich from 1781 to 1788, at Stuttgard from 1809 to 1812, and at Augsburg as above, there were 306 days of rain on the day of the first octant, 325 on the day of the first quarter, 341 (the maximum) on the day of the second octant, 284 (the minimum) on the day of the last quarter, and 290 on the last octant. Some observations which appear to have been made under M. Arago’s per- sonal superintendence may be quoted in confirmation of the fact, that the greatest amount of cloud follows upon the moon’s first quarter, and the least amount of cloud on the third quarter, — “The discussion of the observations made at Paris led to the following conclusions :— “The maximum number of rainy days is found to lie between the first quarter and the full moon; the minimum between the last quarter and the new moon ; and the latter number is to the former as 100 is to 126*.” 4. Having pointed out, very briefly, the periods at which (taking one lu- nation with another) the greatest amount of heat or cold is to be expected to recur, and having also suggested a probable cause for the phenomenon, I * Arago’s Popular Astronomy (Admiral Smyth’s translation), vol. ii. p.318. In the same volume, p. 313, there is the following passage in which Sir John Herschel’s explanation of the moon’s influence on the clouds is entirely adopted :—“ In a word, provided we do not lose sight of the fact that the rays which dissipate the clouds are quite different from those whose calorific qualities we have been endeavouring to estimate at the instant when they reach the surface of the earth, the fact which I previously called a prejudice will no longer be contrary to physical laws ; and we shall obtain an additional illustration of the remark, that popular opinion ought not to be rejected without examination.” : Co) 196 REPORT—1859. propose to illustrate the subject by examples of lunar action in the spring and autumn months. Thus in the early part of May, it will be interesting to remark the amount of Lunar Influence exerted at the period of low tem- perature which embraces Dr. Madler’s three cold days, viz. the 11th, 12th, and 13th, and which on an average of 86 years’ observations at Berlin was found to be more than 2 degrees colder than the calculated mean of the season. The following Table of mean temperatures of the first twenty days of May for 43 years at Greenwich, will show the amount of depression which oc- curred at that station. ‘The means are in each case for the civil day. 1st, 50°3 2nd, 51°5 3rd, 50:9 4th, 51:5 5th, 51°8 6th, 51°9 7th, 52°3 8th, 52-1 9th, 51°0 10th, 50°9 11th, 51°6 12th, 51°3 13th, 51°0 14th, 50°6 15th, 51°9 16th, 53°1 17th, 54:0 18th, 53°5 19th, 53°0 20th, 53°9* If we now examine a lunar curve (fig. 3) of the mean temperatures of the 11th, 12th, and 13th days at Greenwich,—they are purposely taken, though not the coldest,—it will not fail to be noticed that the general line of the wave, notwithstanding its pronounced character, follows the model curve, with the exception of a remarkable rise on the second day before first quarter, and on the second day before last quarter. It bears also a very close resemblance to the curve of temperature for the year 1859. A lunar curve of the mean temperature for the month of May during 43 years has also been formed, and found to agree with the model curve; the mean of the means of the day of first quarter and five days after is 54-0, of the day of full moon and five days after 51°°9. The amount of cloud on a seven years’ average for the second day after full moon is 4°9; for the second day after first quarter 8*1; and the mean amount of cloud at the syzygies and quarters for the day of the moon's change and the day preceding and follow- ing is as follows :— At New Moon.......... RIS BELO SS At First Quarter ...........04. 6:9 WE allMinor, 28 crsca' Fs OS 5°7 (the minimum). At Last Quarter .............. 6°3 10 represents an entirely clouded sky. On viewing these results one cannot but recall to mind the belief of the French gardeners in the ravages of “La Lune rousse” towards the end of April or beginning of May ; and the explanation of the phenomenon given by M. Arago,—that it was, without doubt, due fo the absence of cloud. The observations of mean temperature at this period, however, and the relative number of days of the lunation on which they occur, deserve a more minute consideration. To facilitate it, Tables have been formed of the mean temperatures of five consecutive days at full moun, and five corresponding days at first quarter: and for the purpose of reference, a Table of the mean temperatures of the month of May for 43 successive years is appended. On referring to these Tables, it will be at once perceived that the mean temperature of each of the five days at full moon (see Table II.) is far below that of the five days at first quarter (Table I); and also that the number of observations which occurred in the 43 years at the two periods is very different. * From observations kindly furnished by Principal Forbes, of St. Andrews, it appears that the 9th, 10th, and 14th days of May were the co!dest at Edinburgh on an average of 40 years. The 12th, 13th and 14th days, allowing for the estimated march of temperature, were the coldest days at Greenwich. It is possible that the epoch of greatest depression would in a longer series of years coincide with that at Berlin. . LUNAR INFLUENCE ON THE TEMPERATURE OF THE AIR. 197 TABLE I. Day. 1 | »)) | 1 2. 3. | Mean. , | 1829. 57° 1821. 51-1 | 1832. 41-7 10 | 1856. 52:2 | 1848. 611]... 1840. 59:0 | 1843. 49°3 | $ 53-5 1851, 56:3 1829. 55°6 1821. 56:8 11 | 1837. 41:5 | 1856. 56-4 | 1848. 63°7 | .eseeaee 1840. 47:5 | $ 53-9 1851. 56°1 1829, 54°6 ald 12 | 1818. 50°8 | 1837. 42°8 | 1856. 50°7 | 1848. 651! oe 1829. 538 |} 50.6 13 | 1845. 49°9 | 1818. 51-1 | 1837. 428 | 1856. 53-0 | 1848, 64-9 t 1826. 47°38 | 1845. 50°8 | 1818. 49-4 | 1837. 43-8 | 1856. 49°3 | 48-2 14 1815. 57° 15 | 1834. 60-5 | 1826. 48°6 | 1845. 51:3 | 1818. 51-4 | 1837. 45°2 | $ 5251 1853. 50°4 Means| 51-2 526 52-2 54°3 51°6 52°2 No. of Sum Obs. 8 7 6 : 9 38 TABLE Il. Day. 1. fe) 1. 2. 3. Mean. ° 1816. 41-4 i p ; x 10 | 1827. 46-8 | 1819. 58-4 | 1838. 47-5 | 1830. 47-1 | 1849. 42-2 |b 4s:2 1846. 54:3 1835. 52:2 | 1816. 39-4 11 | 1854. 49°0 | 1827. 48°6 | 1819. 57-1 | 1838. 47-5 | 1830. 45°6 | $ 49°1 1846. 533 1824. 46°3 | 1835. 53-0 | 1816. 38°] 12 | 1843. 53:8 | 1854. 52-0 | 1827. 47-3 | 1819. 57°8 | 1858. 515 | $ 50-4 1846. 53-4 1824. 43°8 | 1835. 52:0 | 1816. 40°8 13 | 1832. 38°6 | 1843. 55°3 | 1854. 54-2 | 1827. 48-1 | 1819. 54:4 | $ 48 1846. 53:0 1824, 44:3 | 1835. 44-0 | 1816. 43:8 14 | 1851. 46-2 | 1832. 44-5 | 1843. 52-7 | 1854, 54-7 | 1827. 466 | $ 47:5 1846, 51-2 1824. 42°8 | 1835. 49:0 |1 jo. 15 | 1840. 49:8 | 1851. 50-7 | 1832. 47-4 | 1843. 53°6 | 1854, 55°5 Means| 47°8 499 49°4 489 48-9 49°0 No. of Sum ee } 10 10 10 10 9 ae At full moon the mean temperature of the 10th, 11th, 12th, 13th, 14th, 198 REPORT—1859. and 15th days of the month of May is 49°:0, and the number of observations 49. At first quarter, upon the same six days, the mean temperature is 52°-2, and the number of observations 38. No observations whatever for Ist, 2nd, or 3rd days after first quarter occurred upon the 10th, 11th, and 12th days of May respectively during the 43 years. Again, upon the five days of the lunation at full moon (see Table II.), out of the total number of 49 observations, 27 are found to fall below 50°, and 11 below 45°. At first quarter, out of the 38 observations, the number under 50° is 13 only: those under 45° do not exceed 5. A point of some importance in connexion with the subject should be men- tioned. It did not escape Gen. Sabine’s notice, when engaged on the results of the Meteorological Observations at Toronto, that high mean temperatures prevailed on the 11th, 12th, and 13th days of May on the average of the years 1841-52, at that Station, and it has since been found that they prevailed also at Greenwich during the same period; the mean temperatures of the three days for the 12 years were respectively 53°°5, 53°-2, and 54°1 instead of 51°-6, 51%3, and 510, which are the means of those days on an average of 43 years. It will be found that most of the high temperatures on the three days occurred in years when the mean temperature of May itself was high*. The mean of the month for 43 years is 53°. 5. Ata corresponding period of the year in autumn, the temperature of the second half of lunations which fa!l in October is found as a rule to be uniformly low ; on an average of 43 years it does not exceed 48°9; whilst the mean of the first half (from new to full moon) is 50°4. It was so in the present year; the difference between the mean temperature of four days at first quarter and the mean temperature of four days at last quarter was 23°5 degrees. Upon extracting 14 of the lowest temperatures, or minima of 43 months of October, 13 were found to occur in the second half of the lunation be- tween the day of full moon and the third day before new moon, and 9 of the number at and immediately following on last quarter. They occurred in the following years :— 1814. 38:0 1817. 37°7 1824. 36°4 1825. 37°8 1828. 39°5 1834. 36°9 1836. 28°4 1838. 36°0 1839. 34:7 1842. 35°6 1843. 35°8 1845. 37:9 1848. 38-0 / It is difficult to believe that the following dates are accidental: 1814, 1824, (and 1825), 1834, 1843 ; and 1817, 1828, 1838 (and 1839), 1848. The maxima in October also arrange themselves systematically. There were 4 observations of mean temperature in 43 years which exceeded 62°. They occurred in the following days and years :—viz. in 1834 on the third day after new moon; in 1819 on the second day before full moon; and in 1848 and 1859 on the day of first quarter, and second day after. In 1839 the max- imum was 59°7, and it oceurred on the second day after new moon. The mean of the month of October for 43 years is 49°-6.—More than 75 per cent. of the maxima for the month are found to occur in the first half of the luna- tion. Lastly, the amount of cloud in October for seven years has been extracted from the Greenwich Observations and formed into a Lunar Table. The mean amounts for the day preceding each of the four principal phases and * e.g.the mean of the mean temperatures of the five days at first quarter which occur on the 14th of May exceeds the mean of the five days at full moon which fall on the same day of that month by °7 of a degree only. But the mean temperature of May for the five years in which observations occurred on the above-named day at first quarter was not higher than 49°8. In the instances at full moon it was 51°6. LUNAR INFLUENCE ON THE TEMPERATURE OF THE AIR. 199 four following days (including in each case the day of the change) is as follows :— a NEW WEGGH 5... 35 0's Mae's 71 At First Quarter ............ 79 (the maximum). mt Fol Moons ts. : 327... oo At Last Quarter ............ 61 (the minimum). The mean amount of cloud for the first 14 days of the lunation is 7°3; for the remaining 14 days, 6°4. The figures follow with great precision the course of the model curve and also the curve of mean temperature for 1859. It will be well to recall attention to the principle of alternation and reci- procity which so much affects the mean results of the moon’s action. Many instances of the recurrence of high or low temperatures upon the same day of the lunation were adduced at the Meeting at Leeds: the follow- ing is an amended abstract of some of the more remarkable examples. In the two consecutive years commencing November 1846 and ending October 1848, maximum or minimum temperatures for the month occurred, in 1846-47, three times on the third day before new moon ; twice on the day after new moon; three times on the third day after new moon; twice on the third day before full moon; twice on the second day before full moon; and twice on the third day after full moon. In 1847-48, twice on the third day before new moon ; four times on the day of new moon; twice on the second day before full moon ; twice on the day before full moon; twice on the day of full moon ; twice on the third octant, or fourth day after full moon. Again, in the year 1846-47 there were, amongst others, the following remarkable instances of alternation between opposite phases of the moon :—in December the minimum of the month occurred on the third day before new moon ; in January the maximum on the third day before full moon; in February the minimum on the third day before new moon. And again, the maximum in November 1848 fell on the day of new moon; the minimum in December on the day of full moon. In addition to this, maximum and minimum tempe- ratures were found to occur at intervals of rather more than seven days, and that for several successive months, viz. April, May, June, August, and Sep- tember, or at other lunar intervals. In 1838, exactly ten years earlier, maxima or minima occurred twice on the third day after new moon; three times on the day before full moon; three times on the day of first quarter ; and three times on the day of last quarter. At the Cape of Good Hope, reciprocity of action and the recurrence of high and low temperatures was even more fre- quent and systematic. Thus, in 1855, eight out of the twelve maxima for the month occurred at first quarter, and nine of the twelve minima at new or full moon. In 1842, nineteen maxima and minima out of twenty-four oc- curred on eight days. In 1843, fifteen on seven days ; in 1844, seventeen on six days; in 1845, eleven on four days. The recurrence of maxima and minima at Toronto and Madras was equally marked. On extracting the maximum and minimum mean temperatures for the month, for the respective periods of 43 years at Greenwich, and 22 years at Dublin, it was found that more maxima occurred after the moon’s first quarter than before; the proportion of maxima to minima, on the second day after that phase, being more than 2:1 at both stations. So too on taking the twelve highest maxima and thetwelvelowest minima at Greenwich for the same forty-three years, 48 per cent. of the whole number were found to occur on 200 REPORT—1859. 7 days at first quarter, and minima only, with one exception, before the day of the change. Similar results were obtained from the observations taken at Toronto (from 1843 to 1848). Notwithstanding this, it is certain that the rise in the curve at first quarter and other periods of the lunation is not caused by the presence of maximum temperatures so much as the ordinary means of the several days. Though not at present able to prove the point, I may state my conviction that a close connexion will eventually be established between the occurrence of extreme temperatures (at the several periods of the lunation at which they may most probably be looked for) and the years of maximum and minimum of the solar spots. The year 1858-1859 has been already instanced as one that exhibits many noticeable examples of this increased action. The inquiry will be proceeded with; though as a non-professed Meteor- ologist I much need both indulgence and assistance. TaBxe III. Means of the month of May, for 43 years, at Greenwich, | 1814. 1836. 52°0 | 1847. 56-4 486 | 1825. 53°6 1815. 54-7 | 1826. 50°0 | 1837. 47:8 | 1848. 59-7 1816. 48:8 | 1827. 52:7 | 1838. 50-7 | 1849. 54:0 1817, 47-9 | 1828. 54:3 | 1839. 49:9 | 1850. 51:3 1818. 525 1829. 54:5 | 1840. 53:5 | 1851. 50:9 1819. 542 | 1830. 54:7 ; 1841. 56:8 1852. 51:5 1820. 52:0 1831. 52:8 1842. 53:2 1853. 52:0 1821. 49°4 1832. 51°5 1843. 52°2 1854. 50-9 1822. 55°8 1833. 59°4 1844. 52:9 1855. 488 1823. 54:7 | 1834. 56:9 1845. 49°4 1856. 495 1824, 49°5 1835. 52°9 1846... 54:6, :|— 7a. so ae Mean ...53°°0 | An Account of the Construction of the Self-recording Magnetographs at present in operation at the Kew Observatory of the British Asso- ciation. By BALFour Stewart, M.A. Earcy in 1857 the Government Grant Committee of the Royal Society voted £150 towards the expense of aset of Self-recording Magnetographs te be erected at the Kew Observatory of the British Association; the sum of £250 having been pieviously granted out of the Wollaston fund for the purpose of lighting the observatory with gas. The late Mr. Welsh thereupon applied himself with much zeal to the task of constructing these magnetographs, and devised a plan which was transmitted to Mr. ‘Adie, optician, $95 Strand, who undertook to make the instruments. These were completed by Mr. Adie in a satisfactory manner, and were in operation in July 1857; by the beginning of 1858 all difficulties, whether of a mechanical or photographic nature, had been overcome, and since that date a continuous register of the magnetic clements has been obtained. With regard to the plan devised by Mr. Welsh, the best proof of its excel- lence is the nature of the results obtained, which may be judged of from an average specimen of the curves appended to this Report. Indeed, the ON SELF-RECORDING MAGNETOGRAPHS. 201 superior definition and finish of the lines leaves hardly anything to be desired. Mr. Beckley, the engineer attached to the observatory, very skilfully devised the mechanical details in conformity with Mr. Welsh’s plan, and prepared a working drawing of the instruments*. Mr, Chambers (magnetical assistant at Kew Observatory) assisted in over- coming certain photographical difficulties that arose. He has since been in charge of the instruments, and has performed his task in a very efficient manner, This Report is divided into five sections. In the first section a general and preliminary description is given of the principles of construction of the magnetographs. In the second, a detailed account is given of each of the instruments. In the third section the photographic process is described. In the fourth, the method of ascertaining the instrumental coefficients, and of tabulating from the curves, &c., is detailed; and in the fifth section certain improvements are mentioned which have been made ona set of magneto- graphs since constructed of the same kind as those described. Section I. PreLtimiInary DescrIpTion. The room in which the instruments are placed is one of the lower rooms of the observatory, the roof of which is not much above the level of the ground outside. It is well protected from damp by a vault which goes round the observatory, and is subject to very small changes of temperature, the mean daily range being within 1° Fahr., and the annual range about 20°, the thermometer varying from 50° Fahr. in winter to 70° Fahr. in summer. In shape the room is an octagon, of about 22 feet in diameter, with a height of about 17 feet. Daylight is only admitted through panes of orange-coloured glass, which have the effect of excluding the actinic rays. Four pillars, A, B,C, D (see Plate 3. fig. 1), made of Portland stone, are firmly fixed into the floor. ‘The centres of the pillars B, C, D are in a line perpendicular to the magnetic meridian, while the centres of pillars A and D are in the line of that meridian. ‘The pillars A, B, and C support the three magnetographs, while the pillar D supports the recording cylinders and clockwork. In Plate 3. fig. 1, we have a ground-plan of the instruments, and in fig. 2 an elevation of the same. Referring to the Declination Magnetograph (Plate 3. fig. 1), @ denotes the gas-flame which is the source of light ; 6 is a bull’s-eye lens, the object of which is to condense the light on a narrow vertical slit atc. The bull’s- eye therefore enables the light to be nearly as effective as it would be if ' placed immediately behind the slit e, although in reality it is at a convenient distance from it. After having passed the slit c, the light is conveyed through a covered tube until it reaches the plano-convex achromatic lens set vertically at d, having passed through which, it next falls on two semicircular mirrors which have their centre at e. The faces of these mirrors are exhibited in Plate 4. fig. 3, from which it will be seen that the lower mirror is firmly fixed to a marble slab, while the upper one, which is nearly, but not quite in contact with the lower, is attached to a delicately suspended magnet, and conse- quently moves with it. The light, after leaving the mirrors, is reflected in the direction ef through a piece of plane glass at f, and through a covered tube until it reaches a cylinder hf, the axis of which is horizontal, and which is covered with sensitive paper. The focal length of the lens d is such, that the point h, where the rays * The drawings for the Plates attached to this Report were also made by Mr. Beckley. 202 REPORT—1859. strike the cylinder, is the conjugate focus to the slit ¢; we should therefore have an image of the slit ¢ exhibited on the sensitive paper. As, however, our object is to produce a dot and not a slit of light, a hemicylindrical lens, having its axis horizontal and focus at the cylinder, is placed at g, so that the rays passing through it have the vertical slit of light which they would otherwise have formed on the cylinder compressed into a dot; in which state therefore the light falls upon the sensitive paper. But it is only when both the mirrors, the fixed and the moveable, are in one plane that we shall have one dot upon the cylinder. For if the plane of the one mirror is inclined at an angle to that of the other, the ray from the first mirror will not be reflected in the same direction as that from the second, and will consequently fall upon a different part of the cylinder. Two slits of light will in this case reach the hemicylindrical lens, and two corresponding dots of light will appear upon the sensitive paper which covers the cylinder. The distance between these two dots will be a measure of the angle between the two mirrors, and will consequently (the lower mirror being fixed, and the upper one moving with the magnet) indicate the position of the magnet from time to time. The cylinder round which the sensitive paper is wrapped is moved round by clockwork once in every twenty-four hours, so that the dot belonging to the fixed mirror generates a straight line, while that belonging to the moveable mirror will describe a line corresponding to the movement of the magnet. The arrangements of the horizontal-force instrument are in all respects similar to those of the declination magnetograph which has just been described, with this exception, that in the latter the magnet is in its natural direction, viz. perpendicular to ef, while in the former it is twisted into a direction at right angles to its natural position, and is now in the line ef. The only difference which it is necessary here to notice between the vertical-force magnetograph and those which we have now described, is that in the vertical-force magnetograph the slit ¢ is horizontal and the hemi- cylindrical lens and cylinder vertical, while the axis.on which the moveable semicircular mirror, attached to the magnet, turns, is horizontal. The mirror of this magnetograph is exhibited in Plate 4. fig 5. One piece of clockwork is made to drive all the cylinders. The principle of construction which we have now described seems to possess the following advantages :— Ist. The optical arrangements are such as to secure an exceedingly well- defined dot of light, and by means of suitable photographie appliances, an unexceptionable curve and base-line. 2nd. Should anything occur to change the position of the slit c, both the curve and the base-line will be equally displaced, so that the distance between them (with which only we are concerned) will remain precisely the same as before. Thus too, by slightly altering the positioa of the slit each day, we may put two or even three days’ curves on the same sheet. 3rd. The stone piers, &c. secure perfect steadiness to the apparatus, and the central arrangement presents the advantage that one piece of clockwork drives all the cylinders. Section IJ. DeraiLep DeEscrIPTION OF THE INSTRUMENTS. 1. Declination Magnetograph. The flame used is that of gas, the supply of which is kept constant by ON SELF-RECORDING MAGNETOGRAPHS. 203 means of a water-regulator. The burner consists of a narrow slit about three- quarters of an inch long, and one-hundredth of an inch in breadth. It is placed endwise with respect to the lens, in consequence of which position, the light (coming from a stratum of flame three-quarters of an inch in depth) has its brilliancy greatly increased (see Plate 4. fig. 10 a). The shape of the burner and the arrangement for supplying the flame with air, are in all respects similar to those used in a paraffin lamp, their application to gas having been suggested by Mr. Beckley. The burner is fitted with a glass chimney, the presence of which intensifies the light—it must not, however, fit too tightly. The bull’s-eye lens used for condensing the light of the gas upon the slit is that known as the double condenser. Having passed the bull’s-eye lens, the light falls upon the slit ce. The breadth of this slit is about ~4>th of an inch; a front view of it is given in Plate 4. fig. 10 a. By means of an adjustment, the distance between the gas-flame and the bull’s-eye lens may be altered until the slit is in focus for the gas-flame. The light having passed the slit, goes through a covered tube until it reaches the plano-convex achromatic lens before mentioned. By means of an adjustment, the gas-flame, the bull’s-eye, and the slit may be moved together until the slit be at that distance from the lens which is the conju- gate focus of the sensitive paper. There is also an arrangement by which gas, bull’s-eye, and slit may be moved a little to one side of the central line of the lens, so that the two dots may be made to assume a different position on the sensitive paper. The distance between the slit and the lens is 17°7 inches. This lens is fitted into a glass shade which covers the magnet, as represented in Plate 4. fig. 2. This glass shade stands upon a circular marble slab, diameter 20 inches, thickness 1-2 inch, which is cemented to the top of a solid pillar of Portland stone 4 feet high. There are two holes cut in this glass shade, each about 3 inches in diameter (see Plate 4. figs. 1 & 6), the one to contain the lens above mentioned, through which the rays of light pass on their way from the slit to the mirror ; and the other to contain a piece of plane glass through which the same rays pass on their way from the mirror to the cylinder. The glass shade is gilded inside nearly to the top. This gilding serves the double purpose of reflect- ing back any heat associated with light which may strike it from the outside, and (being a bad radiator) of diminishing as much as possible the currents of air which changes of temperature are apt to produce. The portion of the shade which is not gilded is covered outside with a cloth cap, removeable at pleasure. A vessel containing chloride of calcium is put inside to absorb all moisture. A curved arm of brass (Plate 4, figs. 3 & 4) carries the suspen- sion roller A, and torsion circle C (see also fig. 14:) reading to minutes. The suspension thread is a silk fibre slightly rubbed with bees-wax, in order to render it less susceptible to hygrometric influences. The magnet (D) is a rectangular bar about 54 inches long, 0°8 inch broad, and 01 inch thick. The semicircular mirrors, already alluded to, are also represented in figs. 3 & 4. Their diameter is 3 inches; and great care has been taken that the glass surfaces should be accurately plane and parallel to each other. G is a copper damper, the object of which is to check the oscillations of the magnet, and bring it to rest speedily. The angle aef (Plate 3. fig. 1) being =30° and ef being perpendicular to the magnetic meridian, it follows that the plane of the mirror must be inclined at an angle of 15° to the axis of the magnet, in order that the ray de may be reflected in the direction ef. 204 REPORT—1859. The semicircular mirrors must likewise be placed so that their centre shall be on a level with the centre of the lens. The distance from the lens to the centre of the mirror is 8:1 inches. Having been reflected by the mirror, the light passes through a zine tube fixed to a slate, which connects the declination pillar with the central pillar (see Plate 3. fig. 2), and so reaches the hemicylindrical lens and sensitive paper already described. The distance from the centre of the mirror to the sensitive paper is 63 feet. Hence we have Distance between lens and mirror...... = 8:1 inches. Distance between mirror and cylinder .. 78:0 inches. Total distance between lens and cylinder =86:1 inches. And since the distance between the slit and the lens is 17°7 inches, we find that the focal distance of the lens for parallel actinic rays is nearly 14°7 inches*. Before falling on the sensitive paper, the light passes through a hemicylin- drical plano-convex lens (see Plate 3. fig. 1). The radius of the second sur- face of this lens, is about 0°6 inch, and consequently the distance between this surface and the sensitive paper (in order that the latter may be in focus) is nearly 1:2 inch. 2. Horizontal-force Magnetograph. This instrument is exhibited in Plate 4. figs. 1 & 2. The magnet, mirror, lens, shade, adjustments of light and slit, &c., are in all respects similar to those of the declination magnetograph already described. ‘The peculiarity of the instrument consists in the mode of suspension. A grooved wheel, E (Plate 4. figs. 1 & 2), about 0°3 in. in diameter, has its axle attached to the stirrup which carries the magnet, the plane of the wheel being in the direc- tion of the magnet’s length. The suspension thread, consisting of steel wire (steel being considered little liable to stretch), is carried round the wheel, and the two ends fixed to the suspension roller A (see also fig. 13). A little below the suspension roller the two threads pass over a screw at B, the screw being right-handed where it meets the one thread, and left-handed where it meets the other. Consequently by turning the screw-head, we can vary the distance between the wires until it becomes equal to the diameter of the wheel, and the wires will now be at the same distance from one another throughout their entire length. Let us suppose that the magnet is in the direction of the magnetic meridian. Turn round the torsion circle C (precisely similar to that already described) until the magnet assumes a position at right angles to the magnetic meridian. It is clear that, in order to do this, we shall have to turn the torsion circle through an angle greater than 90°, and consequently that the plane of the wires at their lower extremity will be different from that at their upper. This difference is at present =35° 56’ nearly. ‘The suspension thread is about 11°6 inches long. As the light which falls upon the mirror in the direction de (see Plate 3. fig. 1) must be reflected in the direction ef (def being 30° as before), it follows that the plane of the mirror must make an angle of 75° with the magnetic axis of the magnet. ‘ The distance between the slit and the lens is 17°7 inches, and that between * The focal length of the lens is determined rather by convenience of shape of the instru- ment than by optical considerations. In the declination magnetograph, for instance, if the distance between the slit and the lens were much greater than 17:7 inches, the light, bull’s- eye, and slit could not well be supported by an arm of the slate which is attached to the declination pillar, but wouid require a separate piilar for themselves, ON SELF-RECORDING MAGNETOGRAPHS. 205 the lens and the mirror 8:1 inches, these being the same as in the declination magnetograph ; but the distance between the centre of the mirror and the cylinder is different, being here 4°885 feet. Hence the focal length of the lens for parallel actinic rays is about 14 inches. The hemicylindrical lens is in all respects similar to that already described. 3. Vertical-force Magnetograph. This instrument is exhibited in Plate 4. figs. 5,6 & 7. The vertical-force magnet is of the same size as the others, and is balanced by means of a steel knife-edge upon an agate-plane. It is provided (see Plate 4. fig. 7) at one side with a brass screw working horizontally, and at the other with a similar screw working vertically. By means of these the centre of gravity may be thrown to either side of the centre of suspension, or it may be raised or lowered, and the sensibility of the magnet, when balanced, thereby increased or diminished. These screws are arranged so that there is a preponderance of weight towards the south side of the magnet. This is neutralized partly by the magnetic force tending to pull the north end down, and partly by a slip of brass (H) standing out horizontally towards the north side. Let us suppose the system to be in equilibrium at a certain temperature ; if the temperature rise (since brass expands more than steel), the leverage of the weight at the north side will increase more rapidly than that of the weight at the south. There will therefore be a slight preponderance towards the north, and this may be arranged so as to neutralize to a great extent the decrease in the magnetic moment which an increase of temperature produces. The plane of the magnet is 15° out of the magnetic meridian (see Plate 3. fig. 1), for the following reason. Had the magnet been in the magnetic meridian, it would have been necessary to have placed the mirror inclined at an angle of 15° to the axis of motion of the magnet. This was tried, but it was found that in this position of the mirror, the correction for tempera- ture was so excessive that the instrument became a thermometer, and not a magnetometer. The mirror was therefore put in a plane passing through the axis of motion of the needle, the needle being made to move in a plane inclined 15° to the magnetic meridian. Its temperature correction is at pre- sent very small. The mirror of this instrument is exhibited in Plate 4. fig. 5, one half moving with the magnet, and the other half being fixed to a stand; I is a lifter which may be inserted from without the glass shade, and which, by raising three Ys to catch the needle, may remove it from its position of balance when necessary. A thermometer is inserted within the glass shade of this instrument, by means of which the temperature both of the horizontal and the vertical-force magnets may be determined with sufficient accuracy. In the vertical-foree magnetograph, the slit for the light is horizontal, while the hemicylindrical lens and the cylinder are vertical. It might be thought that with a horizontal slit the style of burner already described would prove unsuitable, as we here require a horizontal and not a vertical light; but by using a burner twice as large every way as those of the other magnetographs, we obtain a light that is found to answer in prac- tice extremely well. The adjustments for regulating the distance between the light and the slit, and between the slit and the lens, are similar to those for the declination and bifilar magnetographs. There is also an adjustment, by means of which the 9206 REPORT—1859. light, bull’s-eye, and slit may be pushed vertically (not horizontally as in the others) a little to one side of the central line of the lens, so that the dots may assume a different position on the sensitive paper. The distance between the slit and the lens is 17°6 inches, that between the lens and the mirror is 8°1 inches, while the distance between the mirror and the cylinder is 6 feet. Hence the focal length of the lens for actinic parallel rays is about 14-4 inches. 4. Registering Cylinder and Clockwork. These are exhibited in Plate 4. figs. 8 & 9. The cylinders are each 6} inches long, and G6 inches in diameter. They consist of brass silvered over. The method of connecting them with the clockwork was devised and executed by Mr. Beckley. The toothed wheel & is driven by the clock- work, and drives the two pinions 7. These pinions, when in gear, drive the two horizontal cylinders by means of teeth attached to the circumference of the latter. Two radial arms, to which the pinions / are attached, enable these to be put out of gear when it is necessary to remove the cylinders. The position of the pinions in this case is indicated in the figure by dotted lines. The vertical cylinder has a toothed rim attached to its lower extremity, which is driven by the crown wheel m. By removing a screw, the cylinder may, when necessary, be detached from its toothed rim, leaving the latter behind. Section II]. DescrIpTION OF THE PHOTOGRAPHIC PROCESS. The process employed is that known as the waxed-paper process, and is thus described by Mr. Crookes. Description of the Wax-paper Photographie Process employed Sor the Photo- meteorographic Registrations at the Radcliffe Observatory. ByW.CRookEs, Esq. 1. Before attempting to select from the numerous Photographic processes the one best adapted to the requirements of Meteorology, it was necessary to take into consideration a number of circumstances comparatively unim- portant in ordinary operations. ae be of any value, the records must go on unceasingly and continu- ously : First. Therefore, the process adopted must be one combining sharpness of definition, with extreme sensitiveness, in order to mark accurately the minute and oftentimes sudden variations of the instruments. Second. To avoid all hurry and confusion, it is of the utmost importance that the prepared paper or other medium be of a kind capable of retaining its sensitiveness for several days. Third. The contraction which paper undergoes during the numerous operations to which it is subject in most processes (in general rather an ad- vantage than otherwise), is here a serious objection; for this reason, the experiment first tried, of transferring to paper the image received on col- lodion preserved-sensitive by the nitrate of magnesia process, was a failure. Fourth. Strong contrast of light and shade, and absence of half-tint, un- fortunately so common amongst ordinary photographie pictures, is in this case no objection. ’ Fifth. It is essential to preserve the criginal results in an accessible form ; and for this reason, the Daguerreotype process, admirably as it seems to answer other requisites, is obviously not the one best suited to our purpose. Lastly, the whole operation should, if possible, be so easily reducible to ON SELF-RECORDING MAGNETOGRAPHS. 207 practice, that with a very small share of manipulatory skill, the loss of even a day’s record would be impossible. 2. Bearing these conditions in mind, on looking over the photographic processes with which I was acquainted, that known as the wax-paper process, first described by M. Le-Gray, seemed peculiarly applicable. In sharpness it might be made to rival collodion ; and although generally stated to be slow in its action, I had no doubt that its sensitiveness could be easily increased to the required degree. Of all paper processes, I believed it to be the one most free from contrac- tion, either during the time it is undergoing the action of the light, or in any subsequent stage. Its chief superiority, however, consisted in its capability of remaining sensitive for so long a time, that it is of little consequence whether the sensitive sheets be a day or a week old. Then the comparative slowness of the development, which has always been looked upon as one of its weak points, would be in this case a positive advantage, as dispensing with that care and attention which must always be bestowed on a quickly deyelop- ing picture. In addition to all these recommendations, it was a process to which I had paid particular attention, and consequently the one in which I might naturally hope to meet with the greatest amount of success. 3. The general outline of the process does not differ materially from that which I published some years back in ‘ Notes and Queries,’ vol. vi. p. 443 ; but as that account was written for practical photographers, the details of the manipulation were brief. It has therefore been thought advisable, that while describing again the whole process, with the addition of such modifi- eations as the end in view requires, I should also give such fuller description of the manipulation, as may render it more serviceable to those who have not hitherto paid attention to photography in its practical details. This must be my excuse, if to some I seem unnecessarily prolix. None but a practical photographer can appreciate upon what apparently trivial and unimportant points success in any branch of the art may depend. It may not be without service, if, before entering into the practical details of the process, I say a few words respecting the most advantageous way of arranging a photographic laboratory, together with the apparatus, chemicals, &e. which are of most frequent use. Among those requisites, which may be almost called absolute necessaries, are gas, and a plentiful supply of good water, as soft as can be procured. 4. The windows and shutters of the room should be so contrived as either to allow of their being thrown wide open for purposes of ventilation, or of being closed sufficiently well to exclude every gleam of daylight ; and the arrangement should admit of the transition from one to the other being made with as little trouble as possible. 5. A piece of very deep orange-coloured glass, about 2 feet square, should be put in the window, and the shutter ought to be constructed so as to allow of the room being perfectly darkened, or illuminated, either by ordinary daylight, or daylight which has been deprived of its photogrephic rays, by filtering through the orange glass. The absorbing power of this glass will be found to vary very considerably in different specimens, and I know of no rule but experience to find out the quality of any particular sample ; the best plan is to select from a good stock one of as dark a colour as possible. The proper colour is opake to the rays of the solar spectrum above the fixed line E. 6. The best source of heat is unquestionably gas. It will be as well, how- ever, to have a fire-place in the room, as, in some cases, a gas-stove will be 208 REPORT—1859. inapplicable. There should be gas-burners in different parts of the room for illumination at night ; and also an arrangement for placing a screen of orange glass in front of each. Several rough deal benches should be put up in different parts of the room, with shelves, drawers, cupboards, &c. ‘The arrangement of these matters must of course depend upon the capabilities of the room. 7. The following apparatus is required. The quantities are those that we have found necessary in this Observatory :— Eight dishes. Six funnels. Eight mill-board covers. One funnel stand. Three brushes for cleaning dishes. Pint, half-pint, one ounce, and A vessel for melting wax. one drachm measures. Two gauze burners. Three glass flasks. One box, iron. Boxes for holding paper. Filtering paper. Scales and weights. A still for water. Sponge, glass rods, stoppered One platinum, and three hone spa- bottles, &e. tulas (flat paper-knives). 8. The dishes may be made of glass, porcelain, or gutta percha. Glass and porcelain are certainly cleaner than gutta percha; but for general use the latter is far preferable, as with it there is no risk of breakage, and the bottom of the dish can be made perfectly flat, whichis a great advantage. These dishes should be made of sufficient length to allow of a margin of about half an inch at each end when the paper is in; and the shape should be made as nearly square as possible, by arranging them to take two or three sheets side by side. The gutta percha should be of a good thickness, otherwise it will bend and give way, if it be moved when full of liquid. The depth must depend upon the size of the dish, and the purpose for which it is intended. The dishes in use here accommodate three sheets of paper side by side ; they are fifteen inches square, and one inch and a half deep. I think, however, for some purposes, where they are not wanted to be moved about much (@. e. those for holding the bath of hyposulphite of soda for fixing), the depth might be advantageously increased to two inches and a half. Each dish ought to be reserved for a particular solution, and should have a piece of millboard a little larger than itself for a cover. 9. The brushes for cleaning the dishes are of two sorts ; a common scrub- bing brush will be found the best for all parts but the corners, and for these another kind must be used, having a handle about a foot long, at the end of which are tufts of stiff bristles, projecting about three-quarters of an inch, and radiating on all sides, forming a ball about two inches and a half in dia- meter. Hardly any dirt will be found capable of resisting this brush if it be pressed into a corner, and twisted round several times. The dishes ought always to be put away clean, as the dirt is much more difficult to remove if allowed to dry on. 10. When a dish is to be cleaned, if it be of glass or porcelain, strong nitric acid must be poured into it; if of gutta percha, it should be filled with a strong solution of cyanide of potassium. After soaking for half an hour or an hour, according to the state of the dish, the liquid is to be returned into the bottle (both the nitric acid and the cyanide can be used several times), the dish rinsed out with water, and then well scrubbed in every part with the brushes ; afterwards it is to be washed several times in common water, once with distilled water, and then placed in a slanting position against a wall, face downwards, to drain on clean blotting-paper. . ON SELF-RECORDING MAGNETOGRAPHS. 209 11. The vessel in which the wax is melted, must be contrived so as never to allow of its reaching a higher temperature than 212° Fahr., or decompo- sition of the wax might ensuc. 1 have found the most convenient apparatus to be, a tin vessel 15 inches square and 4 inches deep, having a tray which holds the wax fitting into it about 1 inch deep. The under vessel is to be half filled with water, and by keeping this just at the boiling temperature, the wax above will soon become liquid. 12. The best source of heat is that known as the gauze gas-burner, it being free from smoke or dust, and not liable to blacken anything placed over it. It consists of a common argand burner fixed on a rather low and heavy iron stand, which is surmounted by a copper or brass cylinder 5 inches in height and 2 inches wide, having a piece of wire gauze of 900 meshes to the square inch fastened over the top. By connecting this burner by means of vulcanized india-rubber tubing to the gas-pipe, it can be moved about the table to any convenient position. ‘The mixture of gas and air, formed inside the cylinder, is to be lighted above the wire gauze; it burns over this with a large and nearly colourless but intensely hot flame. 13. The most convenient form of iron is the ordinary box iron, made hot by heaters inside ; perhaps it might be improved in shape by having the end not quite so pointed, but this is not of much consequence. Some operators recommend facing the bottom with a plate of silver; this is very expensive, and seems to me to be attended with no advantage whatever. 14. For the purpose of absorbing the excess of wax from the surface of the sheet, I should recommend the ordinary white wove blotting-paper, medium thickness. But this is not sufficiently free from impurities to serve either for drying the sensitive sheets, or for filtering ; for this purpose, the fine filtering paper (not the Swedish) employed in quantitative chemical operations is the best. 15. The distilled water being one of those substances upon the purity of which success will in a great measure depend, it will be found much safer to distil it on the premises, especially as the quantity required is trifling. A convenient size for the still is about two gallons; it may be procured ready made, with worm, &c. complete, of any large dealer in chemical apparatus. It will be found far more economical, both in time and trouble, to heat the water over a charcoal or coke fire, in preference to using gas for this purpose. 16. A platinum spatula is a most necessary instrument in almost every operation ; the best size is 4 inches long, } an inch wide at one end, and 3 at the other, the corners being rounded off; it should be of a sufficient sub- stance to prevent its being easily bent. It chief use is to raise one corner of the sheets to allow of their being held between the finger and thumb, for the purpose of removing from one dish to another, as, previous to fixing, none of the solutions should come in contact with the fingers. During the fixing and subsequent washing, bone spatulas will be found very useful; but after having been in contact with hyposulphite of soda, they must be carefully kept away from any of the previous baths, or black stains will infallibly ensue. 17. The funnels may be either of glass or porcelain; it will be found useful to have several of different sizes, from 2 inches diameter, up to6 inches. A convenient stand for them may be made of a piece of flat board, with circular holes, about half the diameter of the funnels employed, drilled into it, and supported upon four legs about 8 inches high. The paper used for filtering should be the finest of the two sorts of blotting-paper mentioned above (14). The filters can either be cut from the sheet as wanted, or they may be obtained ready cut in packets. 1859. P 210 REPORT—1859. The measures should be of glass, graduated, the pint and half pint into ounces, the ounce measure into drachms, and the drachm measure into minims; they shonld be rather long in proportion to their width. The Florence oil-flasks, which can be obtained for a trifle at any oil warehouse, will be found to answer every purpose, nearly as well as the more expensive German flasks. They must be cleansed thoroughly from the adhering oil ; this may be done by boiling in them, over the gauze gas-burner, a strong solution of ordinary washing soda, and afterwards well rinsing out with water. 18, It will be found indispensable, where there are many operations going on at the same time, and many different sheets of paper in various stages of progress, to have a separate box or division to hold the paper in each of its stages. The plan I have found most convenient, is to obtain several mill- board boxes, the fronts of which will fall flat when the lid is lifted up, similar to those used by stationers for holding letter paper, &e.: they can be made to hold two or three piles of sheets side by side. They may be obtained from M. Rousseau, 352 Strand, London. The scales and weights need not be of any great accuracy. A 6-inch beam capable of turning to half a grain, when loaded with 500 grains in each pan, will be all that is requisite: the pans must be of glass, and the weights should consist of a set of grain and a set of drachm weights. A sponge will be found useful for wiping up any of the solutions that may have been spilt on the bench. Solid glass stirring rods of about the thickness of a quill, and six or eight inches. long, and a small Wedgewood pestle and mortar, are of great service in many “of the operations. Stoppered botties should be employed for all the solutions; and too much care cannot be taken to label each bottle accurately and distinctly. 19. Besides the above apparatus, the following materials and chemicals are requisite. A rough estimate is also given of their relative consumption in three months :—Photographic paper, 270 sheets, or 112 square feet ; four pounds of wax; three ounces of iodide of potassium; three ounces of bromide of potassium; four ounces of nitrate of silver ; two ounces of glacial acetic acid ; four ounces of gallic acid ; one pint of alcohol ; seven pounds of hyposulphite of soda; half a pound of cyanide of potassium; half a pint of concentrated nitric acid ; eighteen gallons of distilled water. 20. The selection of a good sample of paper for the basis on which the sensitive material is to be formed is of great importance, as any imper- fection will be a source of annoyance in every stage of the process, and will hardly fail to show itself on the finished picture. The paper, which from numerous experiments I have found to be superior to any other, is that known as Canson’s thin photographic paper. ‘This is manufactured with eare, and isin general very uniform in quality. It will be found by far the most advantageous plan, when used on a scale like the present, to order it of some wholesale stationer cut to the requisite dimensions. The size of the sheets in use here is 42 inches by 121} inches*. ‘Hitherto Messrs. Hallifax and Co., 319 Oxford Street, have supplied us with the paper of this size. 21. I am indebted to Mr. Barclay of Regent Street, wax bleacher, for much valuable information concerning wax and its adulterations, and for * This is a most inconvenient size, as it involves the cutting of more than one-third of the paper to waste. The admirably ingenious arrangement of Mr. Ronalds was not made with the view of employing Canson’s paper, or it would doubtless have heen contrived t accommodate sheets of a size which could be cut with less waste, such as 44 by 13 inches cor 42 by 113 inches, ON SELF-RECORDING MAGNETOGRAPHS. 211 an extensive assortment of waxes of all kinds, and in every degree of purity ; also to Mr. Maskelyne, for a valuable series of the chemical bodies of which the various waxes are composed ; by means of these I have been enabled to examine the effect produced by saturating the paper with ‘bees-wax from different countries, Myrica wax, Canauba wax, China wax, spermaceti, ethal, stearic acid, stearin, palmitic acid, palmitin, paraffin, and various oils. 22. I find that the action of the wax is purely mechanical, almost the only difference of effect produced by any of the above bodies, widely as they vary in their chemical nature, arising from a difference in their physical properties. Stearin, palmitin, and most of the oils, are too greasy in their nature to be advantageously employed. The fatty acids do not make the paper in the least greasy, but they injure the transparency. China wax has almost too high a melting-point, and gives a crystalline structure to the paper. Spermaceti also is too crystalline. Paraffin, ethal, and the waxes, produce very good results; of these bees-wax is the only one that would be practically available for this purpose. It should be free from stearin, stearic acid, tallow, &c.; the presence of a little spermaceti does not much interfere, but as its price does not differ very much from that of pure wax, it is not so common an adulteration as the other cheaper substances. 23. It will be unsafe to use the wax in the form of round thin tablets, ‘about 4 inches in diameter, in which it is usually met with, as in this state it is generally adulterated to the extent of at least 50 per cent. As an article of commerce, it is next to impossible to obtain small quantities of wax sufficiently pure to be relied upon. The only way I can recommend is to apply to one of the well-known large bleachers, and trust to them for supplying the article in a state of purity. Whenever I have found it necessary to make such applications, my request has always been acceded to in the most cordial manner, and every information has been given with the utmost readiness. 24. The other chemicals (with the exception of the strong nitric acid, which any retail druggist will supply, and the water, which had best be ‘distilled on the premises) should be ordered direct from some manufacturing ‘chemist, as otherwise, unless the operator have a sufficient knowledge of chemistry to be able to detect any inferiority, there is danger of not having ‘the articles sufficiently pure. The iodide and bromide of potassium should be ordered purified. The nitrate of silver should be crystallized, not in sticks; it ought to be perfectly dry, and have no smell, acid or otherwise. There are usually two varieties of glacial acetic acid to be met with; the purest must be used; it should be perfectly free from any empyreumatic odour, and must cause no turbidity when mixed with a solution of nitrate of ‘silver, e. g. in making the exciting bath (42), The gallic acid should be as nearly white in colour as possible. Especial care should be taken to have the alcohol good; it should be 60° ‘over proof, and of specific gravity 0°83. On evaporating a few drops on the palm of the hand, no smell should be left behind, nor should it, under the ‘same circumstances, leave any stain on a sheet of white paper. 25. The hyposulphite of soda will be found one of the articles most difficult to obtain pure; there is a large quantity at present in the market, having little else of this salt but the name, and being of course totally unfit for use ; if there be the least doubt about its purity, it should be tested in the following manner :— P2 912 REPORT—]1 859, Weigh out accurately 10 grains of nitrate of silver, dissolve this in half an ounce of distilled water; then add 4 grains of chloride of sodium (common salt), also dissolved in water. On mixing these two solutions together, a white curdy precipitate of chloride of silver will fall down. Next add 22 grains of the hyposulphite of soda, and allow it to stand for about ten minutes, stirring occasionally with a glass rod. If at the end of that time the chloride of silver has dissolved, the hyposulphite of soda may be con- sidered as pure. A greater or less amount of residue will indicate roughly the degree of impurity. 26. The cyanide of potassium is usually met with in the form of hard white lumps; they will be found quite pure enough. It is very useful in removing stains formed by nitrate of silver on the fingers, &c.; but the greatest care must be taken in its employment, as it is a most energetic poison; its use in cleaning the dishes from silver stains has been pointed out above 10). 2 The first operation to be performed is to make a slight pencil mark on that side of the photographic paper which is to receive the sensitive coating. If a sheet of Canson’s paper be examined in a good light, one of the sides will be found to present a finely reticulated appearance, while the other will be perfectly smooth ; this latter is the one that should be marked. Fifty or a hundred sheets may be marked at once, by holding a pile of them firmly by one end, and then bending the packet round, until the loose ends separate one from another like a fan; generally all the sheets lie in the same direc- tion, therefore it is only necessary to ascertain that the smooth side of one of them is uppermost, and then draw a pencil once or twice along the exposed edges. 28. The paper has now to be saturated with white wax. The apparatus for this purpose has been previously described (11). The wax is to be made perfectly liquid, and then the sheets of paper, taken up singly and held by one end, are gradually lowered on to the fluid. As soon as the wax is absorbed, which takes place almost directly, they are to be lifted up with rather a quick movement, held by one corner and allowed to drain until the wax, ceasing to run off, congeals on the surface. When the sheets are first taken up for this operation, they should be briefly examined, and such as show the water-mark, contain any black spots*, or have anything unusual about their appearance, should be rejected. 29. The paper in this stage will contain far more wax than necessary ; the excess may be removed by placing the sheets singly between blotting-paper (14), and ironing them; but this is wasteful, and the loss may be avoided by placing on each side of the waxed sheet two or three sheets of unwaxed photographic paper, and then ironing the whole between blotting-paper ; there will generally be enough wax on the centre sheet to saturate fully those next to it on each side, and partially, if not entirely, the others. Those that are imperfectly waxed may be made the outer sheets of the succeeding set. Finally, each sheet must be separately ironed .between blotting-paper until the glistening patches of wax are absorbed. 30. It is of the utmost consequence that the temperature of the iron should not exceed that of boiling water. Before using, I always dip it into water until the hissing entirely ceases. This is one of the most important points in the whole process, but one which it is very difficult to make beginners pro- perly appreciate. The disadvantages of having too hot an iron, are not * These spots have been analysed by Mr. Malone; he finds them to consist, not of iron, — as is generally supposed, but of small pieces of brass. I have also examined them myself with a like result. : Cy ea Be rat ying ON SELF-RECORDING MAGNETOGRAPHS. 213 apparent until an after stage, while the saving of time and trouble is a great temptation to beginners. It is to a neglect of this point that I am inclined to attribute most of the faults so commonly laid to the charge of this beau- tiful process; such as gravelly appearance, or want of smoothness in the lights, and quick decomposition in the developing solution. 31. A well-waxed sheet of paper, when viewed by obliquely reflected light, ought to present a perfectly uniform glazed appearance on one side, while the other should be rather duller; there must be no shining patches on any part of the surface, nor should any irregularities be observed on ex- amining the paper with a black ground placed behind; seen by transmitted light, it will appear opalescent, but there should be no approach to a granular structure. The colour of a pile of waxed sheets is slightly bluish. 32. ‘The paper, having undergone this preparatory operation, is ready for iodizing ; this is effected by completely immersing it in an aqueous solution of an alkaline iodide, either pure or mixed with some analogous salt. One would think that in no part of the photographic operation would greater unanimity exist, than on the composition of the iodizing bath; but on this subject, strangely enough, no two persons seem to think alike. The formulze for this bath are nearly as numerous as the operators themselves ; and some of them show nota little ingenuity in the manner inwhich substances apparently the most unphotographic have been pressed into service. 33. The results of numerous experiments, which I need not mention here, had convinced me, that for ordinary purposes, iodide of silver per se was the best sensitive surface for receiving an image in the camera; but on making use of that body in these operations (by employing pure iodide of potassium in the bath), I was surprised to meet with results for which I was at first unable to account. A little consideration, however, showed me the direction in which I was to look for a remedy. The experiments which had led me to prefer iodide of silver as a sensitive surface, had all been performed with sunlight, either direct, or more frequently in the form of diffused day- light. In this case, however, coal-gas was the source of light ; and if, as was very probable, there were any great difference in the quality of the light from these two sources, the superiority of iodide over the bromide or chlo- ride of silver would still be a matter for experiment. 34, A comparison of the spectra of the two kinds of light showed a very marked difference; while in sunlight the spectral rays which are around and above the fixed line G (the indigo and higher rays) are so intense and numerous, as completely to overpower the small space between and about F and G (the blue and upper portion of the green), a part of the spectrum which affects bromide more than iodide of silver; in gaslight the case was quite different. The great bulk of photographic rays was found to lie within the limits of the visible spectrum, and consequently the photographie action of this light was likely to be far more energetic on bromide than on iodide of silver. These suppositions were fully borne out by experiment: on intro- ducing a little bromide of potassium into the iodizing bath, the change was very apparent. It requires a certain proportion to be observed between the two to obtain the best results. If the iodide of potassium be in excess, the resulting silver salt will be wanting in sensitiveness, requiring a compa- ratively long development to render an image visible; while, if the bromide be in excess, there will be a great want of vigour in the impression, the picture being red and transparent. When the proportion between the two ds properly adjusted, the paper will be extremely sensitive, the picture pre- senting a vigorous black appearance, without the least approach to red. The addition of a chloride was found to produce a somewhat similar effect to that 214 REPORT—1859. of a bromide, but in a less marked degree. As no particular advantage could be traced to it, it was not employed. 25. I have also tried most of the different forms of organic matter which it is customary to add to this bath, but I cannot recommend them; the most that can be said is, that some of them do no harm. At first I thought a little isinglass might be an improvement, as it instantly removes the greasi- ness from the surface of the paper, and allows the iodide of potassium to penetrate more readily. Unfortunately, however, it interferes with the most important property of this process, that of remaining sensitive for a long time. 36. I think the best results are obtained when the iodide and bromide are mixed in the proportion of their atomic weights ; the strength being as follows :— Iodide of potassium. ‘ ‘ - 582°5 grains. Bromide of potassium . . ‘ « 417°5 grains. Distilled water . : . F 4 40 ounces*. When the two salts have dissolved in the water, the mixture should be filtered; the bath will then be fit for use. 37. At first a slight difficulty will be felt in immersing the waxed sheets in the liquid without enclosing air-bubbles, the greasy nature of the surface causing the solution to run off. The best way is to hold the paper by one end, and gradually to bring it down on to the liquid, commencing at the other end; the paper ought not to slant. towards the surface of the bath, or there will be danger of enclosing air-bubbles; but while it is being laid down, the part out of the liquid should be kept as nearly as possible per- pendicular to the surface of the liquid; any curling up of the sheet, when first laid down, may be prevented by breathing on it gently. In about ten minutes the sheet ought to be lifted up by one corner, and turned over in the same manner; a slight agitation of the dish will then throw the liquid entirely over that sheet, and another can be treated in like manner. 38. The sheets must remain soaking in this bath for about three hours; several times during that interval (and especially if there be many sheets in the same bath) they ought to be moved about and turned over singly, to allow of the liquid penetrating between them, and coming perfectly in contact with every part of the surface. After they have soaked for a suffi- cient time, the sheets should be taken out and hung up to dry; this is con- veniently effected by stretching a string across the room, and hooking the papers on to this by means of a pin bent into the shape of the letter S. After a sheet has been hung up for a few minutes, a piece of blotting-paper, about one inch square, should be stuck to the bottom corner to absorb the drop, and prevent its drying on the sheet, or it would cause a stain in the icture. " 39. While the sheets are drying, they should be looked at occasionally, and the way in which the liquid on the surface dries, noticed ; if it collect in drops all over the surface, it is a sign that the sheets have not been suffi- ciently acted on by the iodizing bath, owing to their having been removed from the latter too soon. The sheets will usually during drying assume a dirty pink appearance, owing probably to the liberation of iodine by ozone in the air, and its subsequent combination with the starch and wax in the paper. This is by no means a bad sign, if the colour be at all uniform; but if it appear in patches and spots, it shows that there has been some irregular * While giving the above as the calculated quantities, I do not wish to insist upon their being adhered to with any extreme accuracy. An error of a few grains on either side. would, I believe, be without any perceptible effect on the result, ON SELF-RECORDING MAGNETOGRAPHS. 215 absorption of the wax, or defect in the iodizing, and it will be as well to reject sheets so marked. 40. As soon as the sheets are quite dry, they can be put aside in a box for use at a future time. There is a great deal of uncertainty as regards the length of time the sheets may be kept in this state without spoiling; I can speak from experience as to there being no sensible deterioration after a lapse of ten months, but further than this I have not tried. Up to this stage it is immaterial whether the operations have been per- formed by daylight or not; but the subsequent treatment, until the fixing of the picture, must be done by yellow light (5). 41. The next step consists in rendering the iodized paper sensitive to light. Athough, when extreme care is taken in this operation, it is hardly of any consequence when this is performed, yet in practice it will not be found convenient to excite the paper earlier than about a fortnight before its being required for use. The materials for the exciting bath are nitrate of silver, glacial acetic acid, and water. Some operators replace the acetic acid by tartaric acid; but as I cannot perceive the effect of this change except in a diminution of sensitiveness, I have not adopted it. It is of little importance what be the strength of the solution of nitrate of silver; the disadvantages of a weak solution are, that the sheets require to remain in contact with it for a considerable time before the decomposition is effected, and the bath requires oftener renewing ; while with a bath which is too strong, time is equally lost in the long-continued washing requisite to enable the paper to keep good for any length of time. The quantity of acetic acid is also of little consequence. 42. In the following bath, I have endeavoured so to adjust the proportion of nitrate of silver, as to avoid as much as possible both the inconveniences mentioned above :— Nitrate of silver. : : : . 300 grains. Glacial acetic acid . : ; : : 2 drachms. Distilled water A r F 3 . 20 ounces. The nitrate of silver and acetic acid are to be added to the water, and when dissolved, filtered into a clean dish (10), taking care that the bottom of the dish be flat, and that the liquid cover it to the depth of at least half an inch all over; by the side of this, two similar dishes must be placed, each con- taining distilled water. 43. A sheet of iodized paper is to be taken by one end and gradually lowered, the marked side downwards, on to the exciting solution, taking care that no liquid gets on to the back, and no air-bubbles are enclosed. It will be necessary for the sheet to remain on this bath from five to ten minutes ; but it can generally be known when the operation is completed by the change in appearance, the pink colour entirely disappearing, and the sheet assuming a pure homogeneous straw colour. When this is the case, one corner of it must be raised up by the platinum spatula, lifted out of the dish with rather a quick movement, allowed to drain for about half a minute, and then floated on the surface of the water in the second dish, while another iodized sheet is placed on the nitrate of silver solution; when this has re- mained on for a sufficient time, it must be in like manner transferred to the dish of distilled water, having removed the previous sheet to the next dish. 44. A third iodized sheet can now be excited, and when this is completed, the one first excited must be rubbed perfectly dry between folds of clean blotting-paper (14), wrapped up in clean paper, and preserved in a port- folio until required for use ; and the others can be transferred a dish forward, 216 , REPORT—1859, as before, taking care that each sheet be washed twice in distilled water, and that at every fourth sheet the dishes of washing water be emptied, and replenished with clean distilled water: this water should not be thrown away, but preserved in a bottle for a subsequent operation (49). 45. The above quantity of the exciting bath will be found quite enough to excite about fifty sheets of the size here employed, or 3000 square inches of paper. After the bulk has been exhausted for this purpose, it should be kept, like the washing waters, for the subsequent operation of developing (49). Of course these sensitive sheets must be kept in perfect darkness. Gene- rally sufficient attention is not paid to this point. It should be borne in mind, that an amount of white light, quite harmless if the paper were only exposed to its action for a few minutes, will infallibly destroy it if allowed to have access to it for any length of time; therefore, the longer the sheets are required to be kept, the more carefully must the light, even from gas, be excluded; they must likewise be kept away from any fumes or vapour. 46. Experience alone can tell the proper time to expose the sensitive paper to the action of light, in order to obtain the best effects. However, it will be useful to remember that it is almost always possible, however short the time of exposure, to obtain some trace of eftect by prolonged develop- ment. Varying the time of exposure, within certain limits, makes very little difference on the finished picture; its principal effect being to shorten or prolong the time of development. Unless the exposure to light has been extremely long (much longer than can take place under the circumstances we are contemplating), ncthing will be visible on the sheet after its removal from the instrument, more than there was previous to exposure ; the action of the light merely producing a latent impression, which requires to be developed to render it visible. 47. The developing solution in nearly every case consists of an aqueous solution of gallic acid, with the addition, more or less, of a solution of nitrate of silver. An improvement on the ordinary method of developing with gallie acid, formed the subject of a communication to the Philosophical Magazine for March 1855, where I recommend the employment of a strong alcoholic solu- tion of gallic acid, to be diluted with water when required for use, as being more economical both of time and trouble than the preparation of a great quantity of an aqueous solution for each operation. 48. The solution is thus made: put two ounces of crystallized gallic acid into a dry flask with a narrow neck; over this pour six ounces of good alcohol (60° over proof), and place the flask in hot water until the acid is dissolved, or nearly so. This will not take long, especially if it be well shaken once or twice. Allow it to cool, then add half a drachm of glacial acetic acid, and filter the whole into a stoppered bottle. 49. The developing solution which I employ for one set of sheets, or 180 square inches, is prepared by mixing together ten ounces of the water that has been previously used for washing the excited papers (44), and four drachms of the exhausted exciting bath (45); the mixture is then filtered into a perfectly clean dish, and half a drachm of the above alcoholic solution of gallic acid poured into it. The dish must be shaken about until the greasy appearance has quite gone from the surface ; and then the sheets of paper may be laid down on the solution in the ordinary manner with the marked side downwards, taking particular care that none of the solution gets on the back of the paper, or it will cause astain. Should this happen, either dry it with blotting-paper, or immerse the sheet entirely in the liquid. 50. If the paper has been exposed to a moderate light, the picture will ON SELF-RECORDING MAGNETOGRAPHS, 217 begin to appear within five minutes of its being laid on the solution, and will be finished in a few hours. It may, however, sometimes be requisite, if the light has been feeble, to prolong the development for a day or more, If the dish be perfectly clean, the developing solution will remain active for the whole of this time, and when used only for a few hours, will be quite elear and colourleas, or with the faintest tinge of brown; a darker appear- ance indicates the presence of dirt. The progress of the development may be watched, by gently raising one corner with the platinum spatula, and lifting the sheet up by the fingers. This should not be done too often, as there is always a risk of producing stains on the surface of the picture. I prefer allowing the development to go on until the black is rather more in- tense than ultimately required, as it is generally toned down in the fixing bath. 51. As soon as the picture is judged to be sufficiently intense, it must be removed from the gallo-nitrate, and laid on a dish of water (not necessarily distilled). In this state it may remain until the final operation of fixing, which need not be performed immediately, if inconvenient. After being washed once or twice, and dried between clean blotting-paper, the picture will remain unharmed for weeks, if kept in a dark place. 52. The fixing bath is composed of a saturated solution of hyposulphite of soda diluted with its own bulk of water. Into this the sheets are to be com- pletely immersed, until the whole of the yellow iodide of silver has been dissolved out. This operation need not be performed by yellow light; day- light is much better for showing whether the picture be entirely fixed. This will take from a quarter of an hour to two hours, according to the time the bath has been in use. It will be well not to put too many sheets into the bath at once, in order to avoid the necessity of turning them over to allow the liquid to penetrate every part. When fixed, the sheet, if held up between the light and the eye, will present a pure transparent appearance in the white parts. The fixing bath gradually becomes less and less active by use, and then its action is very energetic on the dark parts of the picture, attacking and dissolving them equally with the unchanged iodide. When this is the case it should be put on one side (not thrown away), and a fresh bath made. 53. After removal from the fixing bath, the sheets must be well-washed. In this operation, the effect depends more upon the quantity of water used than upon the duration of the immersion. When practicable, it is a good plan to allow water from a tap to flow over the sheets for a minute or two, and having thus got rid of the hyposulphite of soda from the surface, to allow them to soak for about ten minutes in a large dish of hot water. 54. They are then to be dried by hanging up by a crooked pin, as after iodizing. When dry, they will present a very rough and granular appearance in the transparent parts; this is removed by melting the wax, either before a fire, or, what is far better, by placing them between blotting-paper, and passing a warm iron over them; by this means the white parts will recover their original transparency. 55. The picture, arrived at this stage, may be considered finished, as far as is requisite for the purposes of measurement and registration ; sometimes, however, it may be necessary to multiply copies, for the purpose of trans- mitting to other Meteorological Observatories facsimiles of the records, or at least of those containing any remarkable phenomena. I will therefore now detail the method of printing photographic positives from these nega- tives, premising that the process does not differ materially from that usually adopted. 218 ‘ REPORT—1859, 56, The only extra piece of apparatus required, is a pressure frame ; which consists essentially of a stout piece of plate glass in a frame, with an arrangement for screwing a flat board, the size of the glass, tight against it. Though apparently very simple, some care is required, when the frame is a large one, in arranging the screw and board at the back, so as to obtain an equal pressure all over the surface ; unless this is done, the glass will be very liable to break. ‘The pressure frames supplied to us by Messrs. Newman and Murray, 122 Regent Street, are unexceptionable in this respect. The board should of course be well-padded with velvet, and the lateral dimensions of the glass should be the same as those of the gutta-percha dishes (8). . 57. The extra chemicals required for this process are chloride of sodium and chloride of gold. Generally speaking, for the former, common table- salt will be found quite pure enough; but as the quantity required is but small, it will perhaps be found better to obtain some of the recrystallized salt along with the other chemicals. The chloride of gold is merely required for an artistic effect. Many persons object to the reddish-brown appearance of ordinary photographic positives ; the addition of a little chloride of gold to the fixing bath converts this into a rich brown or black ; the trifling quantity required removes any objection to its use on the score of expense. 58. I prefer using the same kind of paper for positives as for negatives (20). Messrs. Canson manufacture a thicker paper, which is generally called positive paper, but I think the thin is far preferable ; the surface is smoother, and the various solutions penetrate much better. ; 59. The first operation which the paper has to undergo is salting ; the bath for this purpose consists of Chloride of sodium..................100 grains. Distilled water .................... 40 ounces. Filter this into a clean dish, and completely immerse the sheets, marked as directed (27). This is best done by laying them gently on the surface of the liquid, and then pressing them under by passing a glass rod over them ; as many sheets as the dish will hold may be thus immersed one after the other. Allow them to soak for about ten minutes, then lift and turn them over in a body ; afterwards they may be hung up to dry (38), commencing with the sheet which was first put in. When dry, they may be taken down and put aside for use at any future time. ‘The sheets in drying generally curl up very much ; it will therefore be found convenient in the next process, if the salted sheets, before being put away, have been allowed to remain in the pressure frame, screwed tight, for about twenty-four hours. This makes them perfectly flat. 60. The exciting bath is composed of Nitrate of silver.................... 150 grains. Distilled water .......,...0.....s... 10 ounces. After filtering, pour the solution into a clean dish ; and then lay the sheets, salted as above, on the surface, face downwards, gently breathing on the back, if it be necessary, to counteract the tendency to curl up; let them remain on this bath for about ten minutes, and then hang up to dry (38). 61. This exciting bath will serve for nearly one hundred sheets ; it will then be better to put it on one side (64), and make a new bath, It is not advisable to excite more positive sheets than will be likely to be required in the course of a week, for they gradually turn brown by keeping, even in the dark, and lose sensitiveness. They will, however, keep much better if pressed tight in the pressure frame, and thus protected from the air. ON SELF-RECORDING MAGNETOGRAPHS. 219 . 62. When a positive is to be printed from a negative, let the glass of the pressure frame be perfectly cleaned and freed from dust on both sides, then lay the negative on it, with its back to the glass. On it place a sheet of positive paper, with its sensitive side down. Then, having placed over, as a pad, several sheets of blotting-paper, serew the back down with suthicient force to press the two sheets into close contact, but of course not so as to endanger the glass. Now place the frame in the sun, so that the light can fall perpendicularly on the glass, and allow it to remain there until it is judged to have been exposed long enough. 63. No rule can be laid down for the proper time of exposure ; it will depend upon the quality of the light and intensity of the negative ; some pictures being completed in a few minutes, others requiring upwards of half an hour. The printing should always go on until the picture is several shades darker than ultimately required. A very little experience will enable the operator to judge so well of the quality of the light, as hardly ever to have a failure. If the two sheets of paper be stuck together in two or three places at the edges with small pieces of gummed paper, the frame can be removed to the dark room, and the progress of the sheets examined ; but this is always attended with some danger, for unless they are replaced without having been shifted one from the other, there will be a double image. 64. As soon as the picture is considered to be printed sufficiently deep, it has to be fixed. The fixing bath consists of Saturated solution of hyposulphite of soda .. .. 10 ounces. Wyner 228 2.5 fi, Saige puese er ees, eh) PRMEEN: This bath will be found to fix the pictures perfectly, but. they will generally be of a reddish tint; if it be thought desirable to obtain the pictures of some shade of dark brown or black, it will be necessary to employ a bath made as follows :— Saturated solution of hyposulphite of soda.... 10 ounces. Md ee fee ey ee er eee or ee 10 ounces. Exhausted positive exciting solution (61) .... 10 ounces. Mix these together, and then add the following :— Wintel: gwici weit eXl sind. grad meat « dy MRAM . 10 ounces. Chloride of.gald. vs seis se dacaiee bead eed ees 20 grains. taking care in mixing to pour the solution of gold into the solution of hyposulphite, and not the latter into the former, or another decomposition will be produced. Pour this mixture into a dish, and lay the positive carefully on it, face downwards. As soon as it is thoroughly damp (which may be known by its becoming perfectly flat after having curled up), immerse it totally in the liquid. "65. The pictures should not be too crowded in the bath, as they are very apt to become irregularly coloured in places where the hyposulphite has not had free access during the whole of the time. When first putin, the colour will change to a light brown, and in the course of some time, varying from ten minutes to two or three hours, it will pass through the different shades of brown to black and purple, gradually fading in intensity during the time. It will be necessary to allow the picture to remain in this bath for ten minutes at least, in order that it may be perfectly fixed. After this time, its stay 220 REPORT—1859, need only be prolonged until it has become of the desired tone and colour; always remembering, that during the subsequent cperation of drying, &e. it will become of a somewhat darker tint than when taken out of the fixing bath. 66. On removal from this bath, the pictures must be allowed to soak in a large quantity of cold water for ten or twelve hours. There must not be very many in the dish at a time, and the water must be changed at least three times during that interval; they must then have boiling water poured over them (of course in a porcelain dish) two or three times, and lastly be pressed dry between sheets of clean blotting-paper (14) (these may be used several times, if dried), and then allowed to dry spontaneously in the air. When the pressure frame is not in use, a pile of these finished positives may be put in, and kept tightly screwed up all night; by this means they will be rendered perfectly flat and smooth. 67. The picture is now complete. It must be borne in mind, however, that the light and shade are reversed by this operation, the track of the luminous image along the paper being represented by a white instead of by a black band, as in the original negative. Should it be desired to produce exact facsimiles of the negatives, it can be done by employing one of these positives as a negative, and printing other positives from it; in this way, the light and shade, having been twice reversed, will be the same as in the original negative. 68. In some cases it may happen that, owing to a partial failure of gas, or imperfection in the sensitive sheet, an image may be so faint as to render it impossible to print a distinct positive. The gap that this would produce in a set of pictures may be obviated, and with very slight sacrifice of accuracy, by forming an artificial or secondary negative in the following manner :— 69. Print a copy on positive paper, of any intensity which will show the most distinct impression; then without fixing, and with a pair of sharp scissors, accurately and carefully cut out the part corresponding to the impressed portion of the negative. Expose this piece to the light until it has become perfectly opake, and then it can either be cemented over the imperfect original sheet, or on a clean sheet of paper, and used as an ordinary negative. It is astonishing what accuracy and quickness in cutting out even the most intricate pictures, may be obtained with a little practice; the error of the scissors is generally within the error of measurement. Supplementary Notes to the above description, embodying some slight changes in the process made at Kew. By C. CHAMBERS. 1. After reaching the stage described in art. 28, a pile of paper is to be made up, in which eight plain (unwaxed) sheets alternate with one waxed sheet, and in this state is to be placed between hot plates and subjected to high pressure for several hours, when the mass of paper will be found to be completely permeated by the wax. The operation is to be repeated four or five times, and the sheets, being separated after cooling, will be ready for iodizing. The operation of pressing is best accomplished with the paper not folded, and of the full size as received from the maker, so that the edges which retain super- fluous wax may be cut off and rejected, and the sheets then cut into pieces of the required shape. Piles half an inch in thickness may be done at once in this way, and using several series of hot plates, any quantity of paper may ON SELF-RECORDING MAGNETOGRAPHS, 221 be put through the press in one night. The hot-pressing apparatus is used by the paper-makers, and by some of the wholesale stationers. 2. The iodizing bath, which should be kept in the dark when not in use, consists of— Todide of potassium...... 5824 grains. Bromide of potassium... . 4173 grains. Distilled water ........ 40 ozs. Iodine—sufticient to give the solution a decidedly red tinge. With every fresh batch of paper, a small quantity of iodine should be added to restore the red tone of the bath. The paper is to be hung up to dry in a dark cupboard, and, when dry, it should be of a light reddish-brown colour; if a deep red or purple, it will want sensitiveness ; if nearly white, it will want keeping properties, and will become discoloured during development. 3. The exciting bath contains,— Silerdte Gt AVEr sce pss. wetevelsac+ ss vses (00 293. Distilled water. 225.0... 2k ce lens Scene DONOZSs WNCELIC ACIG., Sasser re sees c leeches 3 drms. A strong solution of nitrate of silver (100 grs. to 1 oz. of water) is kept in a separate bottle for replenishing the exciting bath, which loses by use both in quantity and strength. 2 drms. of this solution with + drm. of acetic acid, is added after exciting every three sheets (300 square inches) of paper. The addition of acetic acid prevents discoloration during development, but at the same time slightly diminishes the sensitiveness, and, if added in excess, the intensity of the image is much weakened. When the bath is more than a fortnight old, it is necessary to filter before using. With a weak and old exciting bath the iodide of silver is apt to fall from the sheet in flakes while in the bath, and the portions of the sheet so deprived of silver are no longer sensitive to light: however, there need be no fear of this occurring while the strength of the bath is maintained as above directed. The same exciting solution has been used as long as three months with satisfactory results (1000 square inches of paper being sensitized weekly ). 4. (Art. 44.) Instead of drying the sheets between blotting-paper, it has been found to give cleaner and more uniform pictures to hang them up to dry in a dark cupboard ; about an inch is cut off each end of the sheet and rejected where the fingers have touched it, and where the fluid has accumu- lated in dripping. 5. It is very desirable that the exciting and fixing operations should be performed at different times; for if, after fixing, the hands have not been care- fully washed, the least remnant of fixing solution left upon the fingers is communicated to the edge and dispersed over the moist surface of the newly sensitized sheet, producing a stain which appears on developing. Ifa series of black spots, proceeding from one corner of the sheet, show themselves while developing, the cause should probably be looked for in the exciting operation—a drop of the solution accidentally got on the upper side of the floating sheet having trickled down when the sheet was held vertically : when this occurs, it is better (instead of merely floating) to immerse the sheet in the two washing dishes (see art. 43). 6. A sheet of plate-glass, 20 inches by 18 inches, ground at the edges to prevent the solution from flowing off, is used for developing. This was pro- posed by Mr. Welsh, and it is found to answer extremely well: it rests upon 599 *RpPpORT—1859. a wooden cross-piece which fits into a large earthenware dish, and is capable of being roughly levelled by means of screws which support the dish. It is raised about an inch above the bottom of the dish. A solution con- sisting of— Distilled water ........ °° 8 ozs, Acetic acids .\5. 4 gee L Crm, Old exciting bath ...... 4 drms. (or 1 drm, of solution of nitrate of silver 100 grs. to 1 02.) Gallic acid solution .... 14 drm. (see art. 48) is poured upon the plate, and the exposed sheets floated side by side upon it. The time required for this operation varies from two hours in summer to six or eight hours in winter. Note.—In dull weather, the sensitive paper above described may be used with advantage for printing copies of the curves—requiring an exposure of only a few seconds to diffused daylight. Section IV, On THE METHOD oF ASCERTAINING THE INSTRUMENTAL COEFFICIENTS, TABULATING FROM THE CURVES, ETC. 1. Declination Magnetograph. In this instrument the distance between the centre of the mirror and the registering cylinder is 6'5 feet, and consequently a change in the position of the dot of light on the sensitive paper, equal to one inch, denotes a change of 2218 in the position of the magnet. The mirrors are so arranged that the moveable dot is north of the fixed dot on the cylinder (see Plate 3. fig. 1); an increase of declination therefore will bring the two dots nearer together, while a decrease of declination will have the opposite effect. Should the suspension thread be without torsion altogether, or should its torsion remain constant, the same distance between the two dots of light will always denote the same absolute declination; so that if by any means we know the absolute declination corresponding to a given distance between the dots, we shall be able to tell what it is for any other distance, or, in fact, for any moment of time. The comparability with one another of the various tracings afforded by the instrument, depends on the constancy of the torsion; should this vary, the curves are no longer absolutely comparable. Great attention should therefore be paid to secure, if not an entire absence of torsion, at least a constancy in the little that remains. The thread should be well freed from torsion when the magnet is suspended : by slightly rubbing it with bees-wax, or by some other similar process, it should be rendered less susceptible to hygrometric influences, and a dish of chloride of calcium should be kept under the glass shade to absorb all moisture. When the magnet is in perfect adjustment, there can be no objection to seal the shade to the marble slab all round with bees-wax, at least if an ordinary loosely fitting shade be used. Besides all this, it is necessary to make at least every month at some spot free from the influence of iron, observations of absolute declination, noting the precise moment at which each observation is made. The distance be- tween the two dots of light, that is to say between the curve and the base- line of the declination magnetograph, at the moments of observation, wik ON SELF-RECORDING MAGNETOGRAPHS. 223 afford us corrections, which, when applied to our monthly absolute determi- nations, should bring them all to the same value: in other words, the self- recording magnetograph affords us the means of eliminating the changes that are constantly taking place in the value of the magnetic declination. Should, however, the torsion of the suspension thread of the declination magnetograph have become changed to any extent, our corrected monthly determinations will no longer have the same value. We are thus presented with a test, by means of which we may ascertain whether change of torsion in the suspension thread, or some other circum- stance, such as the change in position of some neighbouring mass of iron, has affected our magnetograph. The following results show that the mag- netograph herein described has stood this test in a very satisfactory manner :— Time of observation of Declination reduced by absolute declination. magnetograph to Jan. 1858. “ IRA Manually, uc asasis ociowdydaad ys after Sh OO: 9F Pebruatlyé s3 sie les eiereccis eS Seat sa BD. 64) 47 Marohadiech ) tanse i nessewiodatede sr ZlnhGul 2 APT asi KOT Kee i pwatnn $4 6e000e 9: A)) S660 Mags de aise Ai pewe walstes oF stlewk gee) a6 As AUsmab iiscird a dew tne detainee tern BL'Sb 38 September .......... seat axle on Zl Bho Mctabek agis wow suk aang d Veiees th BREE PeaOrOetaberies, dm 0 68st tb tines vy 21.57 7 November ......... Bs SIAS ostids Bf tds a 21 56 38 December: jz ewirsti.e6 sen ttSes oe) Blo Bh..68 Before concluding this part of the subject, I may remark that the magneto- graphs are merely intended to serve as differential instruments; so that, in addition to their employment, absolute values of the magnetic elements require to be taken from time to time. On this account also, although it is very de- sirable to have, if possible, no torsion in the thread of the declination mag- netograph, and no iron in its neighbourhood, yet the value of the result does not depend so much on the entire absence of these sources of error as in the eonstaney of the effects which they produce. The greatest caution should therefore be exercised in excluding any hygrometric influence which might change the torsion, and the greatest pains taken to prevent any shifting of iron in the neighbourhood of the instruments. ' 2. Horizontal-foree Magnetograph. ‘We have in this case two things to determine, viz. the temperature cor- rection, and the yalue of one inch on the cylinder in parts of force, With .regard to the first of these, the most trustworthy method is to make the ob- servations themselves determine their own temperature correction by means of comparing together two periods, for which the average temperature is different, while the average horizontal force is known to be the same for both. It is, however, advisable that the temperature correction of the horizontal- force magnet should be well determined in the ordinary manner before mounting it. With regard to the scale coefficient, or value of 1 inch in parts of force, it may be well to exhibit in detail the process by which the scale coefficient of the present horizontal-force magnetograph bas been determined, There are two methods by which the scale coefficient is determined. In the first of these, let » denote the angle which the plane of the upper extre- mities of the wire makes with that of the lower; dv the change, in parts of 294 REPORT—1859. radius, which is occasioned on v by the moveable dot traversing the sensitive paper one inch; & the scale coefficient, or value of one inch in parts of force; then k=cotvov. By this formula, 2, or the scale coefficient, may be determined when v is known. Let us determine v accurately when the magnet is mounted, that is, let us find accurately the angle which the plane of the upper extremities of the wire makes with that of the lower for a certain distance between the fixed and the moveable dot of light upon the cylinder, then we can always find the value of v. Loss of magnetisin in the magnet may have widened the distance between the dots on the cylinder since we first determined v*, but knowing the angular value of one inch we can make allowance for this, and thereby determine the present value of », which will be somewhat less than the first. The loss of magnetism may even have obliged us to turn the torsion circle, in order to bring the dots of light nearer to one another, and of course an accurate account must be taken of this, and allowance made for it in cal- culating for the future the values of v. Taking these circumstances into account, viz. the amount of change of the torsion circle, and the distance between the dots, v may always be determined, and, consequently, by the above formula, the scale coefficient may be known. But as there is some doubt of the rigorous truth of the conditions which the above formula assumes, another method of determining the scale coefficient has been proposed which does not seem open to any such objection. Let a deflection bar be arranged as in Plate 3. fig. 4 a, 4 a, so as to support a magnet horizontally placed, with its axis in the magnetic meridian, and so that if prolonged it would pass through the centre of the bifilar magnet. Let the centre of the two magnets be at the distance 7 from one another. The presence of the deflecting magnet will of course have changed the posi- tion of the moveable dot upon the cylinder. Bring the bifilar magnet speedily to rest, and allow the deflecting magnet to remain in its position for about five minutes: this time will sufficiently enable us to procure a photographic impression of the position of the bifilar magnet when deflected ; and having its position before and after, we shall thus be enabled to estimate the amount of deflection. Let this be 2 inches. Take the same deflecting magnet and place it in a similar position with respect to the declination magnet, and also at the distancer. Here it is obvious that the axis of the deflecting magnet is at right angles to the magnetic meridian. Determine photographically, as before, the angle of de- flection which it has caused; let this be w; then &, or the value of one inch tan uw in parts of force for the bifilar magnetograph= Example. On April 30, 1858, the deflecting magnet having been applied as above to the bifilar magnetograph, the deflection produced was=2°887 in. The same magnet being applied in a similar manner, and at the same di- stance, to the declination magnet, the deflection was =3*560 inches =78' 58”. tan 78’ 58” se Se ()) . k 9-887 00796 A similar observation having been performed at the distances 2°5 and 3°0 feet, we find as a mean result on that date, k='00800. Hence * In the declination magnetograph a decrease of distance between the dots denotes an in- crease of westerly declination, while in the bifilar and vertical-force magnetographs it denotes an increase of horizontal and vertical force respectively. 4 ON SELF-RECORDING MAGNETOGRAPHS. 225 On December 2, 1859, a similar set of observations gave k=:01004. These may be taken as the correct values of & at their respective dates, but we wish to obtain the values of & for intermediate dates. In order to do this, let us make use of the other formula, k=cot vo v. On April 30, 1858, » was nearly =43° 13’; hence 1 k=cot 43° 13’x% —-_ ='0 ‘ co x i17-h 09078 On December 2, 1859, v=35° 56’; hence se Sigplscin ts kes k=cot 35° 56’ x li7a4 011769. By the first or more correct formula we find the change that had taken place in the value of & between the two dates to be ‘00204, while by the latter formula the change is ‘002691. We cannot go far wrong in supposing that the real change upon & is equal to that given by the formula (k=cot v dv) multiplied 00204 009691" Hence to find the real value of & for any value - by the fraction of v, we have __*00204: Apa Ol. aay {cot vdv—-00907 8} +:00800. In these instruments it is of great importance to have magnets which lose their magnetism very slowly ; for it is the loss of magnetism, rather than any other cause, which renders it necessary to turn the torsion circle, and occa- sions changes in the value of the scale coefficient, In connexion with this magnetograph, it is necessary to make frequent observations of absolute hori- zontal force, noting the precise times at which the observations are made. Such observations will serve to eliminate from the results of the horizontal- force magnetograph those changes which are occasioned by loss of magnetism and stretching of the suspension thread. It is particularly desirable to make absolute observations immediately before and after turning the torsion circle. 3. Vertical-force Magnetograph. The temperature correction of this instrument, if fitted with a slip of brass, as in the present instance, will have to be determined by the observations themselves. It is well, however, as a measure of precaution, to determine the temperature coefficient of the magnet before it is mounted. With regard to the value of one inch in parts of force, there are two methods by which this may be determined, viz. the method of vibrations, and that of deflections. With respect to the former of these— Let T denote the time of vibration of the magnet in a vertical plane ; T’ the time of vibration of the magnet in a horizontal plane* ; © the magnetic dip ; Y the vertical component of the earth’s force ; which suppose to become Y+ OY, occasioning a change in the angular posi- tion of the magnet represented by ée; then it may be shown that a li . Yor cot Ode. el so as to have the same moment of inertia which it has in the vertical plane. . Q 226 REPORT—1859. Again, since the normal to the mirror is inclined at an angle of 15° to the incident ray, and since the sensitive cylinder is 5-965 feet, or 71°58 inches distant from the mirror, it may be shown that the vertical space of one inch traversed by the luminous dot upon the cylinder, represents an angular change in the position of the magnet 143-16 x cos 15°’ hence the value of 1 inch in parts of force par” cot 8 ~ 'F® 143-16 cos 157 The second method, by which the value of one inch in parts of force may be determined, is that of deflections. Let.a suitable apparatus (see Plate 3. figs. 5A, 5a) be contrived, by means of which a deflection magnet, m, may be placed vertically with its centre at a given distance, 7, from that of the ver- tical-force magnet and in continuation of the magnetic axis of the latter magnet, when horizontal. Let the change of position of the luminous dot upon ea cylinder be registered photographically as before; let this be =n inches. Let the deflecting magnet be now placed with its centre at the distance r from that of the declination magnet, and in continuation of the magnetic axis of the latter magnet; also let the magnetic axis of the deflecting magnet be perpendicular to the magnetic meridian ; and, finally, let the angle through which the declination magnet is deflected be determined photographically. Call this angle w; then it may be shown that the value of one inch in parts of force for the vertical-force magnet is found from the following expression :— tan wu Value of one inch= é ntan O By the method of vibrations the value of one inch was determined on February 27th, 1858, to be =00221 in parts of force, while by the method of deflections (mean of three distances) its value was found to be ="00211 in parts of force. There is thus a very satisfactory agreement between the results of the two processes. On April 18th, 1860, the value of one inch was determined by the method of deflections to be =:00249 in parts of force. There is thus a change ='00038 which has taken place in the value of one inch during the course of about two years. This has no doubt been occasioned by loss of magnetism of the magnet widening the distance between the dots and rendering it necessary to alter the balance of the magnet by means of the horizontal screw from time to time. A proper method of interpolation will enable us to determine with suffi- cient accuracy the value of 1 inch in parts of force for any period between February 27th, 1858, and April 18th, 1860. It is perhaps a safe rule to determine the value of the scale coefficients of bifilar and vertical-force magnetographs,by the method of deflections, once a year. Monthly observations of dip are made at Kew, which, combined with the monthly determinations of absolute horizontal force, will enable us to deter- mine the absolute vertical force, and thus to eliminate from the vertical-force curves the changes that have been occasioned by loss of magnetism from time to time. Method of tabulating from the curves.—By pushing the dots of light forward a little, two days’ curves are recorded on each sheet of sensitive ee ON SELF-RECORDING MAGNETOGRAPHS. 999 paper. These sheets are therefore only changed every second day. ‘This change is made a little after 10 A.m., and the time occupied in making it is about ten minutes, while that occupied in pushing forward the dots is only about three minutes. There is thus every day a loss of ten and of three minutes alternately, so that the curves never record precisely the whole of the twenty-four hours, but generally something less by a few minutes. The precise moment (Kew mean time) of stopping the pendulum and of setting it going again is noted, so that the length of time for which any curve is a record is known and is attached to the curve in writing. (See curves appended to this Report, Plate 5.) The instrument for tabulating from the curves is represented in Plate 3. fig. 3 a: ab is a time-scale commencing and ending with 22%. This scale is moveable round a as a centre, and the centre a is also moveable in a hori- zontal direction. Part of the instrument, d fg, is moveable in a vertical direction by means of h, the head of a pinion which works into the rack 7; d serves as a vernier for the scalee. The piece ed efg is moveable in a horizontal direction by means of a slide which fits into the slot k 2; fand g are two tubes through which the eye looks at lines on a piece of glass (ex- hibited separately at full size in fig. 3a). These are two sets of double lines which are etched on glass, the sets being exactly two inches apart. The distance between the tubes f and g is also two inches, so that when the upper pair of lines is placed under f, the lower pair is under g. The glass is firmly attached in this position to the moveable piece d fg, so that the double lines remain exactly under the tubes in whatever manner d fg is moved. The breadth between the two lines (which together constitute a double line) on the piece of glass is a little greater than the breadth of the curve or zero- line on the photographic paper. In order to measure the distance between the curve and zero-line, the photographic paper is set between two pieces of plate-glass, and so adjusted, that when the tube g is set over the zero-line, it may continue to be approxi- mately over it in any part of its horizontal range. Suppose now that e de fg is at the extreme left, the vertical line of the piece of glass lying along the commencement of the curve and that of the zero-line. Set the time-scale ab so that the edge of the index e may touch that hour on the time-scale which corresponds to the commencement of the curve. Adjust the vertical height of 6, the extremity of the time-scale, so that when e def g is carried to the other or right-hand extremity of the curve, the index ¢ may touch that division of the time-scale which corresponds to the termination of the curve. Were the same length of base-line always to denote the same space of time, there would be no need of altering the inclination of a 6; but the rate of the clock may vary a little, or the paper may fit more or less loosely to the cylinder, so that an inch of the base-line will not always denote precisely the same space of time. Having thus adjusted the time-scale, in order to find the distance between the base-line and the curve for any hour, set the index ¢ to the required time, move the pinion head / until the upper pair of etched lines at f are over the curve-line, and read off the height on the scale e by means of the vernier d. Next move the pinion head / until the lower pair of etched lines at g are over the base-~ line, and read off by means of the vernier as before. The difference between the readings for the curve and the base-line plus two inches, gives the distance between these lines. In case any shifting should take place, it is best to read the curve and its corresponding base-line consecutively, instead of reading first a number o points of the curve together, and then the corresponding points of the base- Q2 228- REPORT—1859, line together also. Occasionally the presence of iron for a short time may cause an abrupt rise and fall of small size in the curve, the one motion being due to the approach of the iron, and the other to its removal. These must be taken into account in tabulating from the curves. An instance of this occurs in the curves appended to this Report. Section V. IMpROVEMENTS IN THE CONSTRUCTION OF A SET OF SELF- RECORDING MAGNETOGRAPHS SINCE MADE. Magnetographs very similar to those here described have been lately set up ina house constructed to receive them about 70 yards from the Kew Observatory. The following improvements were made in their construction :— 1. Instead of one large glass shade standing upon the marble slab, each magnetograph has a gun-metal cylinder, which stands upon the slab, and is surmounted by a glass shade of comparatively small size. An opening is cut in the side of the cylinder, in which there is inserted a piece of perfectly plane gluss ; this glass covers that space which in the old arrangement would have been occupied by the two round holes already described. The lens is apart from the cylinder, and has an adjustment to admit of its distance from the mirror being altered if necessary. This arrangement permits the shades to be removed without disturbing the lenses. It also renders the working of the instrument less liable to inter- ruption in case of any accident happening to the shade. There is also a tube inserted through the marble, which may be connected with an air-pump and the interior of the cylinder and shade exhausted, if this be thought necessary. 2. The second improvement consists in having reading telescopes with ivory or other scales mounted on pillars, and so placed that the light from the divisions of the scale falling upon the moveable mirror attached to the magnet is reflected into the telescope. In consequence of this, the motion of the mirror will cause an apparent motion of the scale in the field of view of the telescope. The position of the magnet will therefore be known by observing what division of the scale is in contact with the vertical wire of the telescope. We may thus combine the photographic record with eye observations. The advantage of the latter is that we see what is taking place at the very moment of its occurrence, whereas we only obtain the photographic record a couple of days after the changes to which it relates have happened. Should a disturbance take place, we are thus not only made aware of it at the time of its occurrence, but we may, by having a telescope scale of greater range than the recording cylinder, obtain eye observations, when owing to excessive disturbance the dot of light has altogether left the sensitive paper. Report on the Theory of Numbers.—Part I. By H. J. Srernen Smirg, M.A., Fellow of Balliol College, Oxford. 1. Tue ‘ Disquisitiones Arithmetic” of Karl Friedrich Gauss (Lipsiz, 1801) and the ‘ Théorie des Nombres’ of Adrien Marie Legendre (Paris, 1830, ed. 3) are still the classical works on the Theory of Numbers. Nevertheless, the actual state of this part of mathematical analysis is but ON THE THEORY OF NUMBERS. 229 imperfectly represented in those celebrated treatises. The arithmetical memoirs of Gauss himself, subsequent to the publication of the ‘ Disquisi- tiones Arithmetice ;’ those of Cauchy, Jacobi, Lejeune Dirichlet, Eisen- stein, Poinsot, and, among still living mathematicians, of MM. Kummer, Kronecker, and Hermite, have served to simplify as well as to extend the science. From the labours of these and other eminent writers, the Theory of Numbers has acquired a great and increasing claim to the attention of mathematicians. It is equally remarkable for the number and importance of its results, for the precision and rigorousness of its demonstrations, for the variety of its methods, for the intimate relations between truths apparenily isolated which it sometimes discloses, and for the numerous applications of which it is susceptible in other parts of analysis. “The higher arithmetic,” observes Gauss*, confessedly the great master of the science, “presents us with an inexhaustible store of interesting truths,—of truths, too, which are not isolated, but stand in a close internal connexion, and between which, as our knowledge increases, we are continually discovering new and sometimes wholly unexpected ties. A great part of its theories derives an additional charm from the peculiarity that important propositions, with the impress of simplicity upon them, are often easily discoverable by induction, and yet are of so profound a character that we cannot find their demonstration till after many vain attempts; and even then, when we do succeed, it is often by some tedious and artificial process, while the simpler methods may long remain concealed.” 2. It is the object of the present report to exhibit an outline of the results of these later investigations, and to trace (so far as is possible) their connexion with one another and with earlier researches. An attempt will also occasionally be made to point out the dacune which still exist in the arithmetical theories that come before us; and to indicate those regions of inquiry in which there seems most hope of accessions to our present knowledge. In order, however, to render this report intelligible to persons who have not occupied themselves specially with the Theory of Numbers, it will be occasionally necessary to introduce a brief and summary indication of principles and results which are to be found in the works of Gauss and Legendre. It is hardly necessary to add that we must confine ourselves to what we may term the great highways of the science; and that we must wholly pass by many outlying researches of great interest and im- portance, as we propose rather to exhibit in a clear light the mest funda- mental and indispensable theories, than to embarrass the treatment of a subject, already sufficiently complex, with a multitude of details, which, however important in themselves, are not essential to the comprehension of the whole. 3. There are two principal branches of the higher arithmetic :—the Theory of Congruences, and the Theory of Homogeneous Forms. The first of these theories relates to the solution of indeterminate equations, of the form a, 2" +a,_,v""'+....+a,x+a,=Py, in which @, @,_,...a, a, and P are given integral numbers, and x and y are numbers which it is required to determine. The second relates to the solution of indeterminate equations of the form PE tay. t, ==, in which M denotes a given integral number, and F a homogeneous function * Preface to Eisenstein’s ‘ Mathematische Abhandlungen,’ Berlin, 1847. 230 . REPORT—1859. > of any order with integral coefficients. In this general point of view, these two theories are hardly more distinct from one another than are in algebra the two theories to which they respectively correspond,—the Theory of Equations, and that of Homogeneous Functions ; and it might, at first sight, appear as if there was not sufficient foundation for the distinction. But, in the present state of our knowledge, the methods applicable to, and the re- searches suggested by these two problems, are sufficiently distinct to justify their separation from one another. We shall therefore classify the researches we have to consider here under these two heads; those miscellaneous investi- gations, which do not properly come under either of them, we shall place in a third division by themselves. (A) Theory of Congruences. 4. Definition of a Congruence.—If the difference between A and B be divisible by a number P, A is said to be congruous to B for the modulus P ; so that, in particular, if A be divisible by P, A is congruous to zero for the modulus P. The symbolic expressions of these congruences are respectively A=B, mod P, A=0, mod P. Thus 7=2, mod 5; 13 =-—3, mod 8. It will be seen that the definition of a congruence involves only one of | the most elementary arithmetical conceptions,—that of the divisibility of one number by another. But it expresses that conception in a form so suggestive of analogies with other parts of analysis, so easily available in calculation, and so fertile in new results, that its introduction into arithmetic (by Gauss) has proved a most important contribution to the progress of the science. It will be at once evident, from the definition, that congruences possess many of the properties of equations. Thus, congruences in which the modulus is the same may be added to one another; a congruence may be multiplied by any number; each side of it may be raised to any power whatever, and even may be divided by any number prime to the modulus. 5. Solution of a Congruence—If » (#) denote a rational and integral function of x with integral coefficients (we shall, throughout this report, attach this meaning to the functional symbols F, f, ¢, &c., except when the contrary is expressly stated); the congruence ¢ (x)=0, mod P, is said to be solved, when all the integral values of 2 are assigned which make the left hand number of the congruence divisible by P; 2. e. which satisfy the inde- terminate equation ¢(#)=Py. It is evident that if =a be a solution of the congruence $(v)==0, every number included in the formula z=a+pP is also a solution of the congruence. But the solutions included in that formula are all congruous to one another and to a. It is proper, therefore, to consider all these congruous solutions as identical, and in speaking of the number of solutions of a congruence to understand the number of sets of incongruous solutions of which it is susceptible. To assign, by a direct method, all the solutions of which a proposed congruence is capable, is the general problem which, in the Theory of Numbers, corresponds to the problem of the solution of numerical equations in ordinary algebra. But the solution of the arithmetical problem is attended with even greater difficulties than that of the algebraical one; and the attention of geometers has been turned with more success to the improvement of the indirect or tentative methods of solution, and to the discovery of criteria of possibility ‘er impossibility for congruential formule, than to their direct solution. It is to be observed that, by virtue of a remark already made, the ¢entative ON THE THEORY OF NUMBERS, 231 solution of a congruence involves no theoretical difficulty. For if w=a bea solution, every number included in the formula z=a+ pP is also a solution, and among these numbers there is always one, and only one, comprised within the limits O and P—1 inclusively. By substituting, therefore, for 2 all numbers in succession less than the modulus, and rejecting those which do not satisfy the congruence, we shall obtain its complete solution. But the interminable labour attending this operation, notwithstanding all the abbre- viations in it suggested by the Calculus of Finite Differences, renders its application impossible, except when the modulus is a low number. 6. Systems of Residues.—The set of numbers 0,1,2....P—1 (or any set of P numbers respectively congruous for the modulus P to those numbers) is termed a complete system of residues for the modulus P. By a system of residues prime to P, we are to understand a complete system, from which every residue has been omitted which has any common divisor with P, Thus 1, 5,7, 11, or 1,5, —5, —1, are the terms of a system of residues prime to 12. The word Residue is employed instead of Remainder, because the word Remainder would suggest the idea of a positive number less than the modulus or divisor; whereas it is frequently convenient to consider residues differing from those positive remainders by any multiples of the modulus whatever. 7. Linear Congruences.—The general form of a linear congruence is ax+b6b=0, mod P; a, 6, and P denoting given numbers, and # a number to be determined. The theory of these congruences may be considered to be complete, both as regards the determination of the solutions or roofs themselves and of their number. Ifa be prime to the modulus, there is always one solution, and one only ; if a have a common divisor with the modulus which does not also divide b, the congruence is irresoluble; if 6 be the greatest common divisor of a and P, and if 6 also divide 6, the congruence has 6 solutions. In every case when the congruence is resoluble, the direct determination of its roots may be made to depend on the solution of a congruence of the form az==1, mod P, in which ais prime to P. This congruence coincides with the indeterminate equation ax=1-+Py, methods for the solution of which were known to the ancient Indian geometers*, and have been given in Europe by Bachet de Meziriac+ Eulert, and Lagrange§. The methods of these writers ultimately depend on the conversion of a vulgar fraction into a continued fraction, and in one form or another have passed into every book on algebra. Nor would it have been proper to allude to them here, were it not that they serve to supply us with a clear conception of what we have a right to expect in the solution of an arithmetical problem. In such problems, we cannot expect to express the guesita as (discontinuous) analytical functions of the data. Such ex- pressions may indeed, in many cases, be obtained (by the use of the roots of unity or by other methods) ; but the results of the kind which have hitherto been given, though sometimes of use in calculation, may be said, with few exceptions, to conceal rather than to express the real connexion between the * See the Arithmetic of Bhascara, cap. xii., and the Algebra of Brahmegupta, cap. i. in Mr. Colebrooke’s translation, London, 1817. _ + Problémes plaisans et délectables, qui se font par les nombres. Seconde édition. Par Claude Gaspar Bachet, Sieur de Meziriac, Lyon, 1624. (See props. xv. to xxv.) t Comment. Acad. Petropol. tom. vii. p. 46, or in the Collection of Euler’s Arithmetical Memoirs (L. Euleri Commentationes Arithmeticz Collecte, Petropoli, 1849), vol. i. p. 2; and in his Elements of Algebra, part ii. cap. 1. § Sur la Résolution des Problémes Indéterminés du seconde degré. Hist. de I’ Acad. de Berlin, 1767, p. 165. (See Arts 7, 8, and 29 of the Memoir.) Also in the Additions to Euler’s Algebra, sects. i, and iii, (Lyon, an. 111.) 932 REPORT—1859. numbers required and the numbers given. The arithmetical solution of a problem should consist in prescribing a finite number of purely arithmetical operations (exempt from all tentative processes), by which all the numbers satisfying the conditions of the problem, and those only, are obtained. It is clear that this description exactly applies to the methods on which the solution of linear congruences depends; but, unfortunately, the higher arith- metic presents but few examples of solutions of equal perfection. 8. Besides the older methods for the solution of the equation az=1+ Py, others have, in very recent times, been suggested. Of these the following may serve as examples :— A. In the equation az=1-+Py, or the congruence av=1, mod P, form the residues of the successive powers of a@ for the modulus P. If a be prime to P, we shall at last arrive at a power which has +1 for its remainder or residue. The residue of the power immediately inferior to this power is the value of x in the congruence ax = 1, mod P. This solution is evidently an application of Fermat’s Theorem*. B. Let there be P points A, A,... Ap, arranged at equal distances on the circumference of a circle. Join A, to A,,,, A,,, to Ag,,,--.and so on continually. It can be proved that if @ be prime to P, we shall not return again to A,, until we have passed through every one of the P points, and have formed a polygon of P sides. Let X, X,...Xp be the vertices of this polygon, taken in order, and let A,=X,,,,; then a= is the value of a in the congruence az=1, mod P+. C. Let an origin and a pair of axes be assumed in a plane, and let all the points be constructed whose coordinates are integral multiples of the linear unit; call these points unit points. Join the origin to the point (a, P). If a be prime to P, no unit point can lie on the joining line, but on each side of the joining line there will be a point lying nearer to it than any other. Let (£, n,), (£,,) be the coordinates of these points, and let €, : n, < &,: m5 then é,, 7, and &,, n, are the least positive numbers satisfying the equations a n,—Pé,=1, an,— Pé,=—1. The late M. Crelle, of Berlin, in the 45th volume of his Journal (p. 299), has given a very useful table, containing the least positive numbers x, and x, which satisfy the equation a, x,—a@, #,=1, for all values of a, up to 120, and for all values of a, prime to a, and less than it. 9, Systems of Linear Congruences.—The theory of these systems is left imperfect in the work of Gauss (see Disq. Arith. art. 37); but, by the aid of a few subsidiary propositions relating to determinants, we may, in every case, obtain directly all possible solutions of any proposed system; and (what is frequently of more importance) we can decide @ priori whether a given system of linear congruences be resoluble or not, and if it be resoluble we can assign the number of its solutions. The following theorems by which the determination of the number of solutions is, in every case, effected, will sufficiently indicate the nature of these investigations. Let the proposed system of congruences be represented by (1, 1) a,+(1, 2) 2, +(1, 3) a+ -. +, 2) #0, * Binet, sur la Résolution des équations du premier degré en Nombres entiers. (Journal de !’ Ecole Polytechnique, cahier xx., p. 289.) Libri, Mémoires de Mathématique et Physique (Florence, 1829), p. 65-67. Poinsot, Réflexions sur les Principes Fondamentals de la Théorie des Nombres (Paris, 1845), cap. iii. nos. 19 & 20. For another solution by M. Binet, see Comptes Rendues, Xiii., p. 349. See also Cauchy, Comptes Rendues, xii. p. 813. f Poinsot, Reflexions, &c., cap. iii., nos. 17 and 18. — ss ON THE THEORY OF NUMBERS. 933 (2 1) 2, + (2, 2) 2,4 (2) 8) mbes +(2n)m=x, (A). (n, 1) 2, +(x, 2) v,+(% 3) @+ «+ +(” n) @, =U, 3 let the modulus be g, and the determinant 3+ (1, 1) (2, 2)..(”, 2)=D. If the determinant be prime to the modulus, these congruences will always admit of one, and only one, system of solutions, namely, that supplied by the system of congruences k=n dD Dz, = 2 hd an But if D be not prime to q, let g=p,"".p,"? »- ++ where p,, p,, &e. denote different primes. In order that the proposed system should be resoluble for the modulus g, it must be separately resoluble for each of the modules p,”, p.”, &e.; and conversely if it be resoluble for each of those modules, and admit P, solutions when taken with respect to the modulus p,”", P, solutions when taken with respect to the modulus p,”, and so on, it will be also resoluble for the modulus g, and will admit P, x P, x P,...solutions for that modulus. It is, therefore, only necessary to assign the number of solutions of the congruences (A), for a modulus p” which is the power of a prime. Let I,, be the index of the highest power of p which divides D ; and similarly let I, denote the index of the highest power of p which divides all the minors of D which are of order 7; then if I,—In-1 < m, the system (A) (if resoluble at all) admits of p™ solutions; but if I, > m-+In—1, it will always be possible, in the series of differences T,—In-1 Th-1—Thn-2; woee to assign a pair of consecutive terms I,;1—I,, I,—I,-1, satisfying the in- equalities I41—I, > mM =I, —I,_ Hy and then the number of solutions (supposing always that the congruences are resoluble) is expressed by the formula ply-+(—”)m, The analogy of this theory with the corresponding algebraic theory of systems of linear equations is in particular cases very striking. For example, we have in Algebra the theorem “ The system of n linear equations (1,1) 7, +(1, 2) #,+(1, 3) 7+ ..++(1, 2) rn=0 (2,1) v,+ (2, 2) 7,+ (2,3) %, + +++ +(2, 2) %r=0 (n, 1) %, + (2; 2) #,+(m, 3) 2, +++. + (2,2) an=0 implies either that D==Z+ (1, 1) (2,2)... (, x)=0, or else that 7,2... 2%, are separately equal to zero.” In the Theory of Numbers we have the corresponding theorem, “Tf m linear and homogeneous functions of an equal number of indetermi- nates be congruous to zero for a prime modulus, either the determinant of the system is congruous to zero for that modulus, or else every one of the indeterminates is separately congruous to zero.” 10. Fermat's Theorem.—The theory of congruences of the higher orders is so essentially connected with Fermat’s Theorem, that it will be proper before proceeding further to introduce a few considerations relating te that celebrated proposition. 234 REPORT—1859. It may be considered from two different (though closely connected) points of view, each of which has proved equally fertile in consequences. First, it may be regarded as asserting that, if p be a prime number, and z any num- ber prime to p, the remainder left by the power 2?—! when divided by p is unity. It is thus the fundamental proposition in the arithmetical theory of the residues of powers, or, which is the same thing, of binomial congruences. Or, secondly, it may be regarded as asserting that the congruence #?—! = 1, mod p, has precisely p—1 roots; and that these roots are the terms of a system of residues prime to p. It is in this latter point of view that the the- orem is the basis of the general theory of congruences. We may observe that the demonstrations of Fermat’s Theorem point to this twofold aspect. The proof which is found in most English treatises of Algebra (it is the first of those given by Euler*), and which depends on the property of the binomial or multinomial coefficient, would naturally lead us to regard the Theorem in the first point of view. The same may be said of Euler's second demonstration+, which consists in showing that the index of the lowest power of x in the series 1, 2, #*, 2°, &c., which leaves unity for its remainder when divided by p, is either p—1, or some submultiple of p—1; or again of the demonstration of MM. Dirichlett, Binet §, and Poinsot||, which depends on the observation that the terms of a system of residues prime to any modulus, being multiplied by any residue prime to the modulus, still form a system of residues prime to the modulus. But a remarkable proof of the theorem, in the second expression we have given to it, occurs in a memoir of Lagrange]. As this proof (though very elementary) has not been copied by subsequent writers, and is consequently but little known, its nature may be indicated here. Let the product (a+1) (+2) (e+3)....(@+p—1) be represented by aPp—1+ A, gp-2 AsaP—34,.., Ap 9t+ Ap-1, 2 denoting an absolutely indeterminate quantity. Writing e+1 for a, and multiplying by «+1, we obtain the identity (a@+1)P +A, (@+1)P-1+ A, (w+ 1)P-2+... + Ap_1 (@+1) =(a+p) [aP-1+ A, 2P-24 A, aP-384..4A, c+ Ye | whence, by equating the coefficients of like powers of x, we find, Ps Ge) 1.2 * Comment. Acad. Petropol. vol. viii. p. 141, or Comment. Arith. vol. i. p. 21. This is the first demonstration of the Theorem discovered, since the time of Fermat. The memoir containing it was presented to the Academy of St. Petersburgh, Aug. 2, 1736. t Novi Commentarii Petropol. vol. vii. p. 49, or Comment. Arith. vol. i. p. 260. From the point of view in which Fermat presents his theorem, it is not improbable that the de- monstration he had found of it was no other than this of Euler’s. (See Fermati Opera Matheney Tolose, 1679, p. 163.) It has been adopted by Gauss in the Disquisitiones, rt. 49. $ Crelle’s Journal, vol. iii. p. 390, § Journal de I’Kcole Polytechnique, Cahier xx. p. 289. || Reflexions sur la Théorie des Nombres, p. 32. But the principle of this demonstra- tion is employed by Gauss in a memoir published in the Comm. Soc. Gotting. vol. xvi. p. 69, to which we shall have again to refer. (See Art. 19 of this Report.) ‘| Démonstration d’un Théoreme nouveau concernant les Nombres Premiers (Nouveaux Mémoires de l’Académie Royale de Berlin, 1771, p. 125). The ‘new theorem’ is that known as Sir J, Wilson’s, ——S—— ee ee ee ON THE THEORY OF NUMBERS. 235 (p=1) (p—2) 4 (P-1) (p=2) ieee remit wey (p—1) (p—2) (p—3) | (P—1) (p—3) , | (P—2) (p—3) Te as Cr ae rage tae 2 (p—1) Ap-1=1+4+ A,4+A,+A,+.--+ Ap_2- From these equations we successively infer the congruences A, =0, A,=0, A, =0,..-Ap—2=0, and lastly Ap_1 = —1, mod p. We have, therefore, -the indeterminate congruence (v+1) (w+2) (#+3)...(a+p—1) =2P-1 —1,mod p, which is evidently édentical, i.e. it subsists for all values of x. And since, if a,,@,..@p—1 be the terms of any system of residues prime to p, the factors r—a,, x—a,, Y—a,, ... 2—p_1, are one by one congruous to the factors +1, +2, 2+38,..x2+p—l1 taken in a certain order, the products (x—a,) (w—a,) ... (#—ap_ 1) and (v+1) (w+2)...(e@+p—1) are also identically congruous for the modulus p, so that we may write (x—a,) (ax—a,) ..«(@—ap_1) =aP-!—1, mod p. This congruence exhibits in the clearest manner possible what the real nature of the function z?—!—1 is when considered with respect to the modu- lus p, aud explains to us why it assumes a value divisible by p, when we assign to x any integral value not divisible by p. It will be observed that the last of the y—1 congruences included in the congruence (w—1) (w—2) (wx—3)....(@—p—1) =a?-!—1, mod p (which is a particular case of that last written), namely the congruence 1.2.3 ...p—1=—1,modp is the symbolic expression of Sir J. Wilson’s Theorem. 11. Lagrange’s Limit of the Number of Roots of a Congruence.—The full development of the consequences of Fermat’s Theorem requires the aid of the following proposition, which was first given, in a slightly different form, by Lagrange*. “If F (x) be a function of x of z dimensions, such that F (a2) =0, mod p, then a function of x of z—1 dimensions, F, (x), can always be assigned such that we shall have the identical congruence F (2) = (a—a) F, (a), mod p.” Hence we may infer that no congruence, of which the modulus is prime, can have more incongruous roots than it has dimensions; and, if a con- gruence have congruous roots, we obtain a definition of their multiplicity ; viz., if F (7) == («—a)" F, (x), mod p, then we may say that F (a) =0, mod p, has r roots congruous to a. We may also observe that this theorem enables us at once to infer Lagrange’s indeterminate congruence from the first ex- pression of Fermat’s Theorem. For since x?-!—1 is *==0 for the values v1, «=2,.-..¥=p—l, we may, by successive applications of the pre- ceding theorem, show that 2?—!—] == (a—1) (a--2)....(w—p+1), mod p. 12. Theory of the Residues of Powers.—The principal elementary theorems relating to the Residues of Powers are the following. They are all due to ' * Nouvelle Méthode pour resoudre les Problemes Indéterminés en Nombres entiers, (See Hist. Ac. Berl. 1768, p. 192.) The case of binomial congruences of the form 2” = 1 had already been treated by Euler. (See Nov. Comment. Petropol. vol. xviii. p. 85, or Comment. Arith, yol. i. p. 516, art. 28 of the Memoir.) 236 REPORT—1859. Euler*, who was the first to demonstrate Fermat’s Theorem, and to develope the numerous arithmetical truths connected with it. I. If eand f be conjugate divisors of p—1 so that p—l=ef; the con- gruence x= 1, mod p, always admits of f incongruous roots. Let these roots be denoted by @,a,...ay ‘Then each of the f congruences a =a, admits of e solutions, and the ef roots of these f congruences exhaust com- pletely the p—1 residues prime to p. It appears, therefore, that if we raise the residues of p to the power e, they will divide themselves into f groups of e numbers apiece; the e numbers of each group giving, when raised to the power eé, the same residue for the modulus p. The numbers a, a,...a@y, are termed the quadratic, cubic, biquadratic, quintic, &c., residues of p, accord- ing as e=2, e=3, e=4, e=5, &c., because they are each of them congruous to an e™ power (and indeed to an e™ power of e different numbers), and because no other number beside them can be congruous to such a power. Thus every uneven prime has $(p—1) quadratic, and as many non-quadratic residues; every prime of the form 4n+1 has + (p—1) biquadratic residues, and three times as many non-biquadratic residues, &c. Il. It is readily seen that if the same number z satisfy the two congruences xf = |, and af =1, it also satisfies the congruence x7== 1, mod p; where d is the greatest common divisor of f, and f,. If therefore f be the lowest index for which the number 2 satisfies the congruence xf = 1, mod p, fis a divisor of p—1; as indeed appears directly from Euler’s second demon- stration of Fermat's Theorem. Let W (f) denote the number of num- bers less than f and prime to it; then there are always (f) roots of the congruence xf==1, mod p, which cannot satisfy any other congruence of lower index, and similar form. These are called primitive roots of the con- gruence xf==1, mod p; they are also said to appertain to the exponent f. If JS=p—1, the ¥(p—1) primitive roots of the congruence a?—! = |, mod p, are termed for brevity (though the designation is somewhat improper) the pri- mitive roots of p. ‘There are therefore (p—1) primitive roots of p. 13. Primitive Roots—The problem of the direct determination of the pri- mitive roots of a prime number is one of the “cruces” of the Theory of Num- bers. Euler, who first observed the peculiarity of these numbers, has yet left us no rigorous proof of their existence ; though assuming their existence he succeeded in accurately determining their number. The defect in his de- monstration was first supplied by Gauss}, who has also proposed an indirect method for finding a primitive root. This method§ consists in taking any residue a of p, and determining (by the successive formation of its powers) the exponent f to which it appertains. If f=p—1, a is itself a primitive root of p; if not, let b be a second residue of p, not contained in the period of a, (i. e. not congruous for the modulus p to any one of the numbers a°, a, a’,....af—!,) and let the exponent to which bd appertains be determined. This exponent cannot (as is shown by Gauss) be identical with, nor yeta * Kuler’s memoirs on this Theory are,— (i). Theorematum quorundam ad numeros primos spectantium demonstratio. Comment. Arith. vol. i. p. 21. (ii). Theoremata circa residua ex divisione potestatum relicta. Ibid. p. 260. (iii). Theoremata arithmetica novo methodo demonstrata. Ibid. p. 274. (iv). Disquisitio accuratior circa residua ex divisione quadratorum aliarumque potestatum pet numeros primos relicta. Ibid. p. 487. (¥). Demonstrationes circa residua ex divisione potestatum per numeros primos resultantia. Ibid. p. 516. i; t pe the memoir (i) of the preceding note; and Gauss’s criticism on it; Disq. Arith. rt. 96. } Disq. Arith. Art. 52-55. § Ibid, Art. 73-74, ON THE THEORY OF NUMBERS. 237 divisor of, the exponent to which @ appertains ; but it is always possible by a comparison of the values of a and d to determine a third number, ec, which shall appertain to an exponent divisible by each of the exponents to which a and 6 appertain. By proceeding in this way we shall evidently obtain num- bers appertaining to exponents continually higher, till at last we come to a number appertaining to the exponent p—1; i. e. to a primitive root of p. M. Poinsot* proposes the foliowing method. If 2, 9,, 9,.... &c. be all the prime divisors of p—1, raise the numbers +1, +2, +3,... + 4(p-—1), which form a system of residues prime to p, to the powers of which the in- dices are 2, ¢,, 9,, &c.; so as to determine all the quadratic residues of p, and its residues of the powers q,, q,, &c. If from the system of residues 1, 2, 3, ++ -p—l, we successively exclude these residues of squares and higher powers, we shall have ~(p—1) numbers left, which canuot be congruous to any power having an index that divides p—1, and which are consequently (as may easily be shown) the primitive roots of p. This method is very symmetrical; and if the problem proposed be to find all the primitive roots of p, it is sufficiently direct. But it is (like many other direct methods in the Theory of Numbers) of interminable prolixity ; and becomes absolutely impracticable if p be a number even of moderate size, as it requires us to form the residues of the successive powers of the numbers 1, 2,3...4(p—1). Of course, in performing this operation, the multiples of p are to be rejected as fast as they arise; but, notwithstanding this abbreviation, and others which a little experience will readily suggest, Gauss's method is, for any practical purpose, greatly preferable. In a memoir by M. Oltramare in Crelle’s Journal (vol. xlix. p. 161), several considerations are offered for facilitating the determination of the primi- tive roots of primes in numerous special cases. Some, however, of the general results of this memoir are erroneous, at least in expression, and the demonstrations of the more particular conclusions contained in it involve no new principle, but may be obtained by combining the definition of primitive roots with the criteria by which (as we shall hereafter see) we are enabled to decide on the quadratic or cubic characters of the residues of given primes. The following may serve as examples of the very interesting results which are thus obtained by M. Oltramare. “If a be a prime number and Za +1 be also a prime, 2 or a is a primitive root of 2a+1, according as « is of the form 4n+1 or 4n+3.” Thus 2 is & primitive root of 37 and of 83, 11 is a primitive root of 23, 83 of 167, &c. “Tf a be a prime number, other than 3, and if p=2" a+1, where m is = I, be also a prime, 3 is a primitive root of p, unless the congruence 3?”—! +1=0, mod p, be satisfied.” Thus 3 is a primitive root of 89, and of 137. Theorems of the same character will be found in the Théorie des Nom- brest of M. Desmarest. By their aid M. Desmarest has constructed a table giving a primitive root for every prime less than 10,000. 14. Indices.—If y be a primitive root of p, the least positive residues of the p—1 successive powers of y, A ee A La which we may denote by Yv Yo Ys +++ Yp-2 1; are all incongruous for the modulus p. These residues, therefore, irrespective of the order in which they occur, coincide with the numbers 1, 2, 3.. -p—l,. * Reflexions sur la Théorie des Nombres, cap. iy. art, 3. t Paris, 1852, See pp. 275-279. 938 REPORT—1859. i. e. they represent the terms of a complete system of residues prime to p. If yx =a, mod p, «, or any number congruous to « for the modulus p—], is termed the index* of a for the primitive root or base y; and this is expressed symbolically by writing «== Inda, mod (p—1), or «= Indya, mod (p—1). The principal properties of these indices, which it is clear are a kind of arithmetical logarithm, are as follows :— (1) Ind (AB) = Ind A +Ind B, mod (p—1). (2) Ind (A*) = s Ind A, mod (p—1). (3) Ind (> mod ?) = Ind A—Ind B, mod (p—1). [The symbol s mod p ) is used to denote the value of 2 deduced from the congruence Ba = A mod p. ] (4) Indy A= Ind, y!. Indy A, mod (p—1). (5) If A=B, mod p, Ind A=Ind B, mod p—1. In these congruences A and B represent numbers prime to p, s any inte- gral number, and y and y’ two different primitive roots. The great importance of these indices in arithmetical researches has in- duced the Academy of Berlin to publish a volume containing tables of the numbers corresponding to given indices, and of the indices corresponding to given numbers for all primes less than 1000. This volume, the ‘Canon Arithmeticus+,’ was edited by C. G. J. Jacobi, and contains, besides the Tables, a preface explaining the methods which he adopted in their construc- tion. The annexed specimen will serve to exempli‘y the arrangement of the Tables :— p=29 p-1=2"-7. Numeri. Indices. bee eles eke Nilol1l2/3l4a{slel7isi9 10/13/14 24} 8 22/17|25/18 28/11/27|22118/1020| 5|26 1||6| 2/20/26'28/19|16|15| 5/21 1 1|23)21| 2) 3/17/16) 7| 9|15 2\| 7 \12 4/11 23.27 9} 3] 1 212|19| 6)24) 4] 8|13)25|14 M. Burckhardt, to whom arithmetic is indebted for an excellent Table of the divisors of numbers from 1 to 3,036,000{, has inserted in his work, and apparently only to fill up a blank page at the end of the first million, a table stating the number of figures in the decimal period of the fraction ss for every prime number p less than 2500. It is evident that the number P * The reader must be careful to distinguish between the index of a number and the ex- ponent to which the number appertains. The exponent does not depend on the choice of the primitive root: for a given number it has but one value, a, which is such that ee is a the greatest common divisor of the index andof p—1. The index may have any one of y («) different values ; which of these it has, depends on the particular primitive root chosen. + Berlin, 1839. $ Paris, 1814-1817. A Table containing the exponents to which 10 appertains, for every prime less than 10,000, has since been given by M. Desmarest. (See p. 308 of his ‘ Théorie des Nombres.’) ON THE THEORY OF NUMBERS. 239° of terms in the decimal period of 1 ig nothing else than the exponent to which 10 appertains for the modulus py. M. Burckhardt’s table, therefore, at once apprises us that out of the 365 primes inferior to 2500 (2 and 5 are not counted in this enumeration, as being divisors of 10), 10 is a primitive root of 148; because there are 148 primes p below 2500, the reciprocals of which have decimal periods consisting of p—1 figures. Again, for 108 of the remaining primes below 2500, the exponent to which 10 appertains is 4(p—1). Of these 108 primes, 73 are of the form 4%+3, from which it may be inferred that —10 is a primitive root of those 73 numbers. M. Burckhardt’s Table supplies us, therefore, with a primitive root (and that root the most convenient for the purposes of computation) of 148+73=221 out of the 365 primes inferior to 2500. Nor is this the limit to its useful- ness; for when the exponent to which 10 appertains is as high as 3 (p—1) or 4(p—1) or + (p—1), it is possible by methods which Jacobi has indicated to construct the Table of Indices with very little labour. Jacobi says that had it not been for this table of Burckhardt’s he should hardly have ventured on the construction of the ‘Canon Arithmeticus,’ on account of the prolixity and uncertainty of the tentative methods for the in- vestigation of primitive roots. But, while endeavouring to avail himself of the results of M. Burckhardt’s table, for the computation of his own Tables of Indices, in other cases besides those in which that Table immediately fur- nishes a primitive root, he was led to the invention of a general method of procedure, which, as he says, would have enabled him to dispense with the assistance of Burckhardt’s Table altogether, or to extend his Canon to an higher limit which the expense of printing would have admitted. This method is not in principle very different from Gauss’s process for finding primitive roots, but the form which Jacobi has given to it possesses great advantages, for the purpose to which he has applied it. He first of all takes a number @ (not quite at hap-hazard, for quadratic residues can at any rate be excluded by the law of reciprocity ; see inf. Art. 16); and determines its period of residues, and the exponent a to which it appertains. Let aa’=p—1, and let the residues of a, a’, a*...a*, be entered in a Table of which the argu- ments are the indices 1, 2,3,...p—1, opposite to the indices, a’, 2a’, 3a’... aa’, respectively. It has been shown by Gauss that there are always ¥(p~1) a primitive roots for which this assignment is true. A number 6 is then taken, not contained in the period of a, and the residues of its successive powers are formed till we come to the lowest power of it that is congruous to any power of a; so that 6B =a4,mod p. Let GB be the exponent to which } appertains, @ the greatest common divisor of a and , and ct their least common multiple; let also 6A'=p—1. It may be proved that Bees A=tt, where k is some number less than @ and prime to it, so that = is the greatest com- mon divisor of A and a. These relations show, that when we know the numbers a, A, and B, we can immediately find 6, 2, and 6, without having to raise 6 to any power higher than 68. We may then assign to 6 any index of the form /', where Z is prime to 3, and congruous to & for the modulus 0. The number of such values of / (incongruous for the modulus 3) is cathy Oy 240 REPORT—1859. and, whichever of them we take, there will be Loy primitive roots, for which 6 will have the index J’, while a retains the index a’. We must next form the residues of the \X—a products included in the formula a* 6”; where x has any value from 1 toa inclusive, and y any value from 1 to B—1. These residues are all incongruous; the indices of all of them are known ; and, together with the a powers of a already entered in the table, they exhaust all the numbers which have indices divisible by? In practice, it will almost always happen that is equal to p—1. When this is so, nothing remains to complete the operation but to enter in the Table the residues of the numbers a* by opposite to the indices corresponding to them. But, if \ We Y3++ +P 4 (p—1)) Which are congruous, not to numbers in the series 1), T+++74(p—1)) but to numbers in the series —7,, —7r,,.-—7}(p—1). It may be shown (by a method similar to that employed in Dirichlet’s proof of Fermat’s Theorem) that g?(?-) = (—1)*, mod p; so that 1) = (-1)*. Hence if g be a prime as well as p, and &! denote the number which replaces k, when p and q are interchanged in the preceding considerations, we find ma (en It has, therefore, to be shown that k+-k’ =1(p—1)(q—1),mod2. The way in which this is done is different in each of the two demonstrations, and is a little complicated in each of them; but by the aid of a diagram the con- gruence may be demonstrated intuitively (compare Eisenstein: Crelle, xxviii. p- 246). With a pair of axes Ox and Oy construct a system of unit-points in a plane: only let no such points be constructed on the axes themselves. If S be any geometrical figure, let (S) stand for the number of unit-points contained inside it or on its contour. On Oz and Oy respectively take OA=1q9, OB=3p. Complete the parallelogram OACB, and draw its dia- gonals, OQC, AQB, It is then easily seen that aan — (QBO k'=(QBC) — (QOA kh+k'=(ABC) — Ann =(OABC)—2 (AOB =(OABC), mod 2, But (OABC) = 3 (p—1) (g—1); therefore, finally, +h’ = 14 (p—1) (q—1), mod 2. These demonstrations (the lst, 3rd and 5th) introduee no heterogeneous elements into the inquiry (the geometrical method of the preceding article is to be regarded only as an abbreviation of an equivalent and purely arith- metical process); they are based on the principles of the two theories with which the Law of Reciprocity is most intimately connected,—those of the residues of powers, and of quadratic congruences. The third, in particular, appears to have commended itself above the rest to Gauss’s judgment*, * “Sed omnes hx demonstrationes,” (he is speaking, apparently, of the Ist, 2nd, 4th, and 6th,) “etiamsi respectu rigoris nihil desiderandum relinquere videantur, e principiis nimis heterogeneis derivate sunt; prima forsan excepta, que tamen per ratiocinia magis laboriosa procedit, operationibusque prolixioribus premitur. Demonstrationem itaque genuinam hactenus haud affuisse non dubito pronunciare; esto jam penes peritos judicium, an ea, quam nuper detegere successit,” (the 3rd,) “hoc nomine decorari mereatur.’—Comm. Soc. Gott. vol. xvi. p. 70, 246. REPORT—1859. 20. Gauss’s Fourth Demonstration.—The fourth and sixth demonstrations, though somewhat different from one another, are both intimately connected with the theory of the division of the circle. They must, therefore, be re- garded as less direct than the earlier proofs, but they have contributed even more to the methods and resources of the higher arithmetic. The fourth depends on the formula Ltrtrttrt oo... $ret (1? /n....(A) in which ¢ represents (as throughout this Report) an imaginary square root 4 =, SR Qar of —1; 2 is any uneven number, 7x its positive square root, r=cos ~~ =F i sin as . Let the series n Ltrktrtky rh 4 ,, 470-1) pe denoted by p (2, 2) ; in the particular case in which z is a prime number, it is easy to see that w (A, »=() (1,2). Further, p and g denoting two prime numbers, it is found by actual multiplication of the two series (p, g) and w (q, p) that L(p, 9) xv (Gp)=¥ (1, pg); that is (2) (Qa ehre. If we substitute for the functions y their values given by the equation (A), 3 (pq-1)?—4 (p—1)?=3 (g~1)2 : ; we find (Z) (2)= Be Bi , an equation which gives a rela- tion between (2) and (2) coincident with that assigned in Legendre’s Law of Reciprocity. The equation (A) is not easy to demonstrate. It is not indeed difficult to show that the sum of the series on the left-hand side is + Vn when n=1, mod 4; and +2 Wn when n =3,mod4. But the determination of the am- biguous sign in these values appears to have long occupied Gauss. He has effected it in his memoir (the Summatio Serierum, &c.) by establishing the equality Ltrtrttr to. -rim-* =(f—7>") ges ad Pere (rm-2—r—"+2),,..(B), which he obtains by writing 7 for x, and x—1 for m, in the series Oe Sa 4 (—#") (i—am-!) _ (1—2")(1—2™—) (1—2™-?) l—z (1—z)(1—2*) (1—z) (1—2") (1—z"*) a This series when m is a positive integer becomes an integral algebraical function, and is proved by Gauss to be zero if m be uneven; and if m be even, to be equal to the product (1—a) (l—a”)... (l—a™”—!). From this last observation, the demonstration of the formula (B) naturally flows. If” be an uneven number, the formula (A) becomes ltrtr tot wee bre (141)Vn or=0 (A') according as 7 is evenly or unevenly. even. A very different, but a simpler demonstration of these formule (A) and (A'), depending on the properties of the definite integrals +0 ay Ge) Ce cos 2? dz, sin w*dz, or e da, ~ OF —OOO —o ON THE THEORY OF NUMBERS. 247 has been given by Dirichlet in his memoir, “ Application de l’Analyse In- finitésimale 4 la Théorie des Nombres” (Crelle, vol. xxi. p. 135). The same formule have also been deduced by Cauchy from the equation a (Rena 4 eH 4@ 4 e904 (E+ em? + cM" 4 0" +, .), or Lp e-@ 4 e404 90° +, —— Le? 4-1" + e922 4.,,), in which ad=a, a and & denoting real positive quantities, or imaginary quantities the real parts of which are positive. This equation Cauchy obtained, as early as 1817, by the principles of his theory of reciprocal functions; but it is also deducible from known elliptic formule. (See a note by M. Lebesgue in Liouville’s Journal, vol. v. p.186.) If in it we write ge 2 for a*, and lS for 6°, a and 6 being two evanescent quantities n connected by the relation na=2/, the two series na(4+e-® + -40 4 94... .) and 2B (E+e-F + e—40" + e907 4 .,,) te 2 _ 2 ad 2 become respectively wy (1, 2) x| e-* dx, and (l+e 2 dxf) e—* dx; 0 0 2 On io whence, dividing by the definite integral, and observing that a= a/ aor aes n we obtain finally, in accordance with the formule of Gauss, W(1,2)=iVn(1+i%) (1 Mare, For the case in which m is a prime number, the equality (B) has been established in a very simple manner by M. Cauchy} and M. Kronecker ¢. But, as these latter methods have not been extended to the case in which 2 is a composite number, they cannot be used to replace Gauss’s analysis in this demonstration of the law of reciprocity. From the formula (A) combined with the equation w (A, »)=(5) v (1, p), p denoting a prime number, we may infer _ s=p—l s=p—1 (GV P= cos fe > sin s* = =0; . 2 s=0 P s=0 k i s=p—1 hes s=p—1 yi or G V p= sin s” al = Cos s° oad =0, s=0 P s=0 P according as p =1, or =38, mod 4. These formule serve to express the value of the symbol (5) by means of a finite trigonometrical series, and are, therefore, of very great importance, * See M. Cauchy’s Mémoire sur la Théorie des Nombres in the Mémoires de l’Académie de France, vol. xvii. notes ix. x. and xi. See also the Comptes Rendus for April 1840, or Liouville’s Journal, vol. y. p. 154; and compare (beside the note of M. Lebesgue quoted in the text) a memoir by the same author in Liouville, vol. v. p. 42. T In the Mémoire sur la Théorie des Nombres, Note xi., or Liouville, yol, v. p. 161, t Liouville, New Series, vol. i. p. 392. 948 REPORT—1859. Conversely, the circumstance that a trigonometrical summation should depend on the quadratic characters of integral numbers, may serve of itself to show the use of abstract arithmetical speculations in other parts of analysis. 21. Gauss’s Sixth Demonstration.—This demonstration depends on an investigation of certain properties of the algebraical function s=p—2Z f= (—1)8 a*7 s=0, in which p is a prime number, y a primitive root of p, k any number prime to p, and x an absolutely indeterminate symbol. These properties are as follows :— fen os (1) & — (—1)'F p is divisible by ;——" (2) u—(5) zis divisible by 1—2?, (3) If k=q be a prime number, £4—£, is divisible by g. From (1) we may infer that ¢, q-1—( —]) 4 (p-)G-)) p i is divisible by ie and, by combining this inference with (1) and (2), we may conclude = ee that b (E1—2)—=(-)) Pp [(-Ie (ah ()| Galatt 1—a2?P i le b is also divisible by fae ie eee fae Mak (cma ()] 1—aP is the remainder left in the division of the function &, (,7—£,) by ror a —2% But every term in that function is divisible by g; the remainder is therefore itself divisible by g- We thus obtain the congruence q-1 (—1)?-DG-Dp 2 = (4), nod q, which involves the equation (2) (Z)=(-1) 9 (q—-1), ; that is to say, Gauss has given a purely algebraical proof of the theorems (1), (2), and (3), on which this demonstration depends. The third is a simple consequence of the arithmetical property of the multinomial coefficient, already referred to in Art. 10 of this Report; to establish the first two, it is sufficient to ob- serve that Beh aes cp, and &—(5) é, vanish, the first, if 2 be any ima- ginary root, the second, if x be any root whatever, of the equation v?—1=0. If, for example, in the function & we put z=r=cos 28a sin 2m re ob- tain the function p (2, p), which satisfies, as we have Ct the two ri [W(A p)P=(— 1) Fp, and w (h»)=(5) Y(1,p). It is, indeed, simplest ON THE THEORY OF NUMBERS, 249 to suppose a=7 throughout the whole demonstration, which is thus seen to depend wholly on the properties of the same trigonometrical function v, which presents itself in the fourth demonstration ; only it will be observed that here no necessity arises for the consideration of composite values of 7 in the function W (2, x); nor for the determination of the ambiguous sign in the formula(A). In this specialized form, Gauss’s sixth proof has been given by Jacobi (in the 3rd edit. of Legendre’s ‘ Théorie des Nombres,’ vol. ii. p. 391), Eisenstein (Crelle, vol. xxviii. p. 41), and Cauchy (Bulletin de Férussac, Sept. 1829, and more fully Mém. de l'Institut, vol. xviii. p. 451, note iv. of the Mémoire), quite independently of one another, but apparently without its being at the time perceived by any of those eminent geometers that they were closely following Gauss’s method. (See Cauchy’s Postscript at the end of the notes to his Mémoire; also a memoir by M. Lebesgue in Liouville, vol. xii. p. 457; anda foot-note by Jacobi, Crelle, vol. xxx. p.172, with Eisen- stein’s reply to it, Crelle, vol. xxxv. p. 273.) MM. Lebesgue * and Eisenstein + have even exhibited a proof essentially the same ina purely arithmetical form, from which the root of unity again disappears, and is replaced by unity itself. Eisenstein considers the sum C,= (=) (*) ae (“*) in which h,, h,,...kg denote g terms (equal or un- equal) of a system of residues prime to p, the sign of summation extending to every combination of the numbers f,, ,, ..,, that satisfies the congruen- tial condition k,+h,+h,+...+h, =a, mod p. This sum is, in fact, “i coefficient of r¢ in the development of the gth power of the function =p—1 = () rk, which is equivalent in value to Gauss’s function yp (1, p). k=1 k=p—1 D uf From the equation | x (5) r] =(-1)” M p> it follows that k=1 k=p—1 q ee rh ca k=p—1 3 (5) =(-1)” 1) ter 1) sd ts (5) ya. Wheres nl |i | Bg q-\ k=p—1 q Ca= (140-0 0-2) p Ss 4p Aaa again, since | Dy (A) | k=1 k=p—1 k=p—1 k = 3 (*) rkq = (2) x (*) rk, mod g, we have the congruence k=1 P. k=l Cc. = (<) (4) mod g. But these results, which, taken together, establish the Jaw of reciprocity, are obtained by Eisenstein from his arithmetical definition of C,, without any reference to the trigonometrical function y (1, p). If we k=p-—1 k=p—1 write that function inthe form > ri instead of the form (5 7, A=0 k=1 P we obtain from its gth power the coefficient C', considered by M. Le- * See Liouville’s Journal, vol. ii. p, 253, and vol. iii. p. 113. (The proof of the law of re- ciprocity will be found in sect. i. art. 5, and sect. iii. art. 2, of the memoir). See also the memoir referred to in the text, Liouville, vol. xii. p. 457. t Crelle’s Journal, vol. xxvii. p. 322, 250 REPORT—1859. besguee This coefficient, which is connected with C, by the equation Cl.=pr-!+C,, represents the number of solutions of the congruence ata, +a,+..+a7 =a, mod g. From this definition M. Lebesgue de- q=1 duces the equation C!a=p?-!4+(—1)#@-)G-» (5) 2 , and the congru- ence C’,=1 +(2) (2 , mod g, by processes which, though different from P. those of Eisenstein, involve, like them, the consideration of integral numbers only. 22, Other proofs of the Theorem of Reciprocity have been suggested to subsequent writers by a comparison of the different methods of Gauss. The ; Pe ass ‘ symbol 7 denoting a root of the equation = = =0, it is very easily shown that pai ees pel (r—r—P (7? —r-?/)? oe (- 2p 7 )=(-1) 2 P (C) It is natural therefore to employ this equation to replace the equation k=p—1 2 pa > Gy" =(—1) ” p, which presents itself in the 4th and 6th k=1 methods of Gauss. It is also found that the product k=} (p—1) ier rig tiles MEE equal to (2). (D) k=1 riers This is an immediate consequence of the property of a half-system of Resi- dues (see Art. 19 supra) on which Gauss’s 3rd and 5th methods depend. From a combination of the equations (C) and (D), the law of reciprocity is immediately deducible. (See a note by M. Liouville, Compt. Rend. vol. xxiv., or Liouville’s Journal, vol. xii. p. 95, and especially a memoir by Eisenstein, entitled “ Application de l’Algébre a l’Arithmétique transcendante,” Crelle, vol. xxix. p. 177. The proof by the same author in vol. xxxv, p. 257, is the same as that in the earlier memoir, only that the properties of the circular functions, which here replace the roots of unity, are in the later memoir deduced immediately from the definition of the sine as the produet of an in- finite number of factors.) 23. Algorithm for the Determination of the Value of the Symbol (5)— Gauss has shown in the memoir ‘‘ Demonstrationes et ampliationes nove,” already quoted, that, if p be a prime number, the value of the symbol (2) may be obtained by developing the vulgar fraction — in a continued frac- tion, and considering the evenness or unevenness of a certain function of the quotients and remainders which present themselves in the development. Jacobi has observed (see Crelle, vol. xxx. p. 173) that a much simpler rule may be obtained, by the use of his extension of Legendre’s symbol to the case when p is nota prime. The following is the form in which the rule has been exhibited by Eisenstein (see Crelle, vol. xxvii. p. 319). Let p,, p, -be two uneven numbers prime to one another, and let us form by division the series of equations ON THE THEORY OF NUMBERS, 251 Pi =2h,p, + €,p, P,=2hk,p, + ep, “ss pe=DAypusriteespis in which e,, €, «++ €~41 denote positive or negative units, and p,, py, py ++s+s which are all positive and uneven, form a descending series. Let o denote the number of the quantities p-+ey pr+1 in which both p, and e, p,+1 are of the form 4n+3 ; then Pi =(—1)’. The demonstration of this result flows immediately from the definition of Jacobi’s symbol of reciprocity. A numerical example is added (see Disq. Arith. Art. 328) from which the reader will perceive the utility of these researches in their practical applica- tion to congruences. Let the proposed congruence be a* = —286, mod 4272943, where 4272943 is a prime number. We haye to investigate the value of the symbol (aah in which p is written for 4272943. Now (=2*)=(—)x (5) x ()= -() be- P P P P cause (=")=- 1, and G)= +1, p being of the form 82—1. To find the P value of (=) we hay® 143=0 x 4272943 + 143 + 4972943 =29880 x 143-4103 + 143=2 x 103—63 103=2 x 63—23 63=2x 23417 Ro ka—w Fe 9h Wy py 17=2x11—5t 1152x5+1 The obelisk (+) denotes that the equation to which it is affixed is one of those enumerated in o. Hence (caraoa8) =¢ —1)’=—1, and =) =+1, or the proposed congruence is resoluble. Its roots (as determined by Gauss) are +1493445. 24. Biquadratic Residues—Reverting to the general theory alluded to in Art. 12, we see that, when p is a prime of the form 4”+1, the congruence x* —1=0, mod p, admits four incongruous solutions ; these are +1, —1, and the two roots of the congruence 2*-+1==0, mod p, which we shall denote by +fand —f, or by fand /*, so that the four roots of #*—1==0 are 1, f, —1, andf*. Further, if & be any number prime to p, & satisfies one or other of the four congruences— (i.) k*®-2=1, mod p. (iii) 28? ==—1, mod p. (ii) HB?" =f, mod p. (iv.) R*?-Y== f*, mod p. We see therefore that the p—1 residues of p divide themselves into four classes, comprising each 1(p—1) numbers, according as they satisfy the Ist, 2nd, 3rd, or 4th of these congruences. The first class comprises those 952 REPORT—1859. numbers a for which the congruence a*==a, mod p, is resoluble; that is, the biquadratic residues of p; the third comprises those numbers which are qua- dratic, but not biquadratic, residues of p; the second and fourth classes divide equally between them the non-quadratic residues. We owe to Gauss two memoirs* on the Theory of Biquadratie Residues, which, while themselves replete with results of great interest, are yet more remarkable for the impulse they have given to the study of arithmetic in a new direction. Gauss found by induction that a law of reciprocity (similar to that of Legendre) exists for biquadratic residues. But he also discovered that, to demonstrate or even to express this law, we must take into con- sideration the imaginary factors of which prime numbers of the form 4”+1 are composed. By thus introducing the conception of imaginary quantity into arithmetic, its domain, as Gauss observes, is indefinitely extended; nor is this extension an arbitrary addition to the science, but is essential to the comprehension of many phenomena presented by real integral numbers them- selves. Gauss’s first memoir (besides the elementary theorems on the subject) con- tains a complete investigation of the biquadratic character of the number 2 with respect to any prime p=4”+1. The result arrived at is that if p be resolved into the sum of an even and uneven square (a resolution which is always possible in one way, and one only), so that p=a*+6* (where we may suppose a and 6 taken with such signs that a=1, mod 4; b=af, mod p), 2 belongs to the first, second, third, or fourth class, according as 76 is of the form 42, 4n+4+1, 42+2, or 42+3. The considerations by which this con- clusion is obtained are founded (see Art. 22 of the memoir) on the theory of the division of the circle, and we shall again have occasion to refer to them. In the second memoir Gauss developes the general theory already referred to, by which the determination of the biquadratic character of any residue of may in every case be effected. The equation p=a°+6* shows that p= (a+6i) (a—br), or that p, being the product of two conjugate imaginary factors, is in a certain sense not a prime number. Gauss was thus led to introduce as modulus instead of p one of its imaginary factors: an innovation which necessitated the construction of an arithmetical theory of complex imaginary numbers of the form A+Bz. The elementary principles of this theory are contained in the memoir in question ; they have also been developed by Lejeune Dirichlet with great clearness and simplicity in vol. xxiv. of Crelle’s Journal (pp. 295-319, sect. 1-9)t. The following is an outline of the definitions and theorems which serve to constitute this new part of arith- metic. 25. Theory of Complex Numbers.——The product of a number a+40i by its conjugate a—Zi is called its norm; so that the norm of a+: is a*+6°; the norm of a (which is its own conjugate) is a. This is expressed by writing N(a+6i)=N(a—bi)=a° +0’; N(a)=a*. If a and be two complex num- * Theoria Residuorum Biquadraticorum. Commentatio prima et secunda. (Gottingz, 1828 and 1832, and in the Comm. Recent. Soc. Gott., vol. vi. p. 27 and vol. vii. p. 89.) The articles in the two memoirs are numbered continuously. The dates of presentation to the Society are April 5, 1825, and April 15, 1831. + The death of this eminent geometer in the present year (May 5, 1859) is an irrepa- rable loss to the science of arithmetic. His original investigations have probably contributed more to its advancement than those of auy other writer since the time of Gauss; if, at least, we estimate results rather by their importance than by their number. He has also applied himself (in several of his memoirs) to give an elementary character to arithmetical theories which, as they appear in the work of Gauss, are tedious and obscure; and he has thus done much to popularize the theory of numbers among mathematicians—a seryice which it is ime possible to appreciate too highly. yc ON THE THEORY OF NUMBERS. 253 bers, we have evidently N(a)x N()=N(aj). There are in this theory four units, 1, 7, —1, —7, which have each of them a positive unit for their norm. ‘The four numbers a+ i, ia—b, —a—ib, —ia+b (which are obtained by multiplying any one of them by the four units in succession, and which consequently stand to one another in a relation similar to that of +a and —a in the real theory) are said to be associated numbers. ‘These four associated numbers with the numbers respectively conjugate to them form a group of eight numbers (in general different), all of which have the same norm. These definitions are applicable whatever be the nature of the real quantities a and b. If a and 6 are both rational, the complex number is said to be rational ; if they are both integers, a+ di is a complex integral number. One complex integer a is said to be divisible by another 6, when a third y can be found such that a=fy. Adopting these definitions, we can show that Euclid’s pro- cess for investigating the greatest common divisor of two numbers is equally applicable to complex numbers; for it may be proved that, when we divide one complex number by another, we may always so choose the quotient as to render the norm of the remainder not greater than one-half of the norm of the divisor*. If, therefore, we apply Euclid’s process for finding the greatest common divisor to two complex numbers, we shall obtain remainders with norms continually less and less, thus at last arriving at a remainder equal to zero; and the last divisor will be, as in common arithmetic, the greatest common divisor of the two complex numbers. Similarly the funda- mental propositions deducible in the case of ordinary integers from Euclid’s theory are equally deducible from the corresponding process in the case of complex integral numbers. Thus, “if a complex number be prime to each of two complex numbers, it is prime to their product.” “If a complex number divide the product of two factors, and be prime to one of them, it must divide the other.” ‘The equation av—by=1, where a and 6 are complex numbers prime to one another, is always resoluble with complex numbers x and y, and admits an infinite number of solutions,” &c. A prime complex number is one which admits no divisors besides itself, its associates, and the four units. There are three distinct classes of primes in the complex theory :— 1. Real prime numbers of the form 4%+3 (with their associates). 2. Those complex numbers whose norms are real primes of the form 42+1. 3. The number | +2 and its associates the norm of which is 2. Instead of dividing numbers into even and uneven, we must here divide them into three classes, uneven, semi-even, and even, according as they are (1) not divisible by (1+2); (2) divisible by 1+7, but not by (1+2)’; (3) divisible by (1+7)°=2z, or, which is the same thing, by 2. Of four associated uneven numbers, there is always one, and only one, such that d is even and a+6—1 evenly even. This is distinguished from the others as primary. Thus —7 and —5+42 are primary numbers. A primary number is congruous to +1 for the modulus 2(1+7); whence it appears that the product of any number of primary numbers is itself a primary number. The conjugate of a primary is also primary. In speaking of un- even numbers, unless the contrary is expressed, we shall suppose them to be primary. This definition of a primary number is that adopted by Gauss (2. e. Art. 36), and after him by Eisenstein, and we shall adhere to it in this at+hi _act+bd , be—ad aes et+di cd? c?+d? ret p+qiis the quotient required. i; if p be the integral number nearest to eophd and * Since ord g that nearest to 954 REPORT—1859. Report. But Gauss has also suggested a second definition (which is for some purposes slightly more convenient), and which has been adopted by Dirichlet, who defines a primary uneven number to be one in which 6 is un- even, anda=1, mod 4. The object of singling out one of the four associated numbers is merely that it serves to give definiteness to many theorems. For example, the theorem that “every real number may be expressed as the product of powers of real primes in one way, and in one only,” may be now transferred in an equally definite form to the complex theory, “ Every complex number ean be expressed in one way only in the form 7”(1 +7)" A*. BP. Cy ++. Where m, ”, a, (3, y, &c. are real integral numbers, A, B, C... primary complex primes.” If a+6i be a complex number, and N=N(a+i)=a’+06’, and if h be the greatest common divisor of a and 4, it can be shown that every number is congruous, for the modulus a+ i, to one, and one only, of the numbers r-+iy, where x=0, 1, 2,00. a1 ;y=0,1,2,....4—1. These numbers therefore (or any set of numbers congruous to them) form a complete system of residues for the modulus a+, The number of the numbers x+7y is evidently N, so that the norm of the modulus represents the number of residues in a complete system. In particular, therefore, if the modulus a +2 be a prime of the second kind, having p for its norm, the num- bers 0, 1, 2,...—1 represent a complete system of residues; and if the mo- dulus be a prime of the first kind, as —q, the numbers included in the formula x+y, where x and y may have any values from 0 to g—1 inclusive, will re- present a complete system of residues. 26. Fermat's Theorem for Complex Numbers.—Dirichlet’s proof of this theorem for ordinary integers is equally applicable to complex numbers, and leads us to the following result :— “If p be a prime in the complex theory, and & any complex number not divisible by p, then ANP-1==1, mod p.” Again,the demonstration of the theorem of Lagrange (see Art. 11) is equally applicable here (see Gauss, Theor. Res. Big., Art. 50), and therefore the general theorems mentioned in Art. 12 may be extended, mutatis mutandis, to the complex theory. In particular, the number of primitive roots will be LN(p)—1], or the number of numbers less than N(p)—1, and prime to it. It will follow from this that, if the modulus be an imaginary prime p, every primitive root of Np in the real theory will be a primitive root both of p and its conjugate. Those Tables of Indices, therefore, in the ‘Canon Arithmeticus,’ which refer to primes of the form 42+1 will continue to hold, if for the real modules we substitute either of the imaginary factors of which they are composed. For primes of the form 4%+3 (considered as modules in the complex theory), it would be requisite to construct new tables, —a labour which no one as yet appears to have undertaken. 27. Law of Quadratic Reciprocity for Complex Numbers.—If p and q¢ be any two uneven primes (not necessarily primary, but subject to the condition that their imaginary parts are even), and if we denote by =| the unit-resi- q due of the power p}(Ni—-1], mod q; so that | 2 | = +1, or =—1, according as Pp is or is not a quadratic residue of ¢: then a law of reciprocity exists, which is expressed by the equation [=| — [2] . ON THE THEORY OF NUMBERS. 255 If p and g are both real primes, it is easily seen that either of them is a quadratic residue of the other in the complex theory, or [2] — [2|= 2 But, as p may or may not be a quadratic residue of ¢ in cea of real integers, we see that the values of the symbols [| and (“) are not neces- sarily identical. This theorem is only enunciated in Gauss’s memoir (Art. 60), and, as he speaks of it as a special case of the corresponding theorem for biquadratic residues, it is probable that his demonstration of it was of the same nature with that which he had found of the law of biquadratic reciprocity. How- ever, a simple proof of it, depending on Legendre’s law of. reciprocity, has been given by Dirichlet in Crelle’s Journal*. He shows that, if g be a prime of the first kind, [<* | =(="); and that, if a+ 62 be any prime of the second kind in which 3 is even, “5 — (42+68 a+b a+b? city is easily deducible from these transformations. If, for example, a+6i, a+ i, be primes of the second species in which both 6 and # are even, we have simultaneously aCe) CS] where p=N (a+bi); @=N (a+). But (=F) = (=a) by Jacobi’s formula (see Art. 17 supra); and we tt?) = ( a ) Also ) The law of recipro- aa+bpy pa=(aa+bB)’+(ab—ba)’; whence we infer (; Le )=1, or, which is the a ' BN hy ia Ve a+r] _ te] same thing, Sor 0: 4) = oa)’ and therefore finally, Ee mil Lat Bil? The complementary theorems which have to be united with this formula i hy She (Ci LS Sih reer pg das ol Ae ae eee (see Dirichlet, Crelle, vol. xxx. p. $12); and they, as well as the formula of reciprocity itself, admit of an extension similar to that which Jacobi has given to the corresponding formule of Legendre. 28. Reciprocity of Biquadratic Residues——We now come to the theorem which first suggested the introduction of complex numbers. If p be any (complex) prime, and & be any residue not divisible by p, we denote by a the power 7 of i, which satisfies the congruence k#(NP-Y=>=7, F Pp 8 It will be observed that when p is a prime of the second species, the quadri- partite classification of the real residues of p which we thus obtain is identical with that which we obtain for Np in ‘the real theory (see Art. 24 supra) ; for the numbers f and —f being the roots of the congruence x” +1==0, mod Np, * Crelle, vol, ix. p. 379. 256 REPORT—1859. satisfy the same congruence for either of the complex factors of Np, and are therefore congruous to +2 and —2, for one of those factors, and to —? and ¢ k aer +2 for the other. Admitting this definition of the symbol (). Gauss’s law of biquadratic reciprocity is expressed by the equation (i.) [s] accor (E> a and ( denoting two primary uneven primes, and A and B being their norms. The complementary theorems relating to the unit ¢ and the semi-even prime 1+ are % tN esata), ied 1+@ \ _ ;#((at0-a+0y) (ii.) a) +> 9(ill.) ara), ; in which a+ ia! denotes a primary uneven prime. These formule, like those of the last article, are susceptible of the same generalization which Jacobi has applied to Legendre’s symbol; and we may suppose in the first that a and (3 are any two primary uneven numbers, prime to one another; and in the second and third that a+7a! is any primary uneven number. If, in the formula (i.) which expresses the law of reciprocity, a=a+ia’, P=b+ib', it may be easily seen that the unit (—1)#(4-)+(-) is equal to (—1)?@-03%-), This gives us a second expression of the theorem. (See Eisenstein, Math. Abhandl. p. 137, or Crelle, vol. xxx. p. 193.) Further, if we observe that every primary number is either =1, mod 4, or else =3+2i, mod 4; and that }(A—1)1(B—1) and }(a—1)1(6—1) are even numbers, except both a and f satisfy the latter congruence, we may enunciate the law of biquadratic reciprocity by saying— “The biquadratic characters of two primary uneven prime numbers with respect to one another are identical, if either of the primes be = 1, mod 4; but if neither of them satisfy that congruence, the two biquadratie characters are opposite.” This theorem is only enunciated by Gauss, who never published his demons stration of it. ‘ Non obstante,” he observes, “summa huius theorematis sim- plicitate ipsius demonstratio inter mysteria arithmetice sublimioris maxime recondita referenda est, ita ut, saltem ut nunc res est, per subtilissimas tantum modo investigationes enodari possit, quee limites preesentis commentationis longe transgrederentur.’—Theor. Res. Biq. Art. 67. Soon after the publication of the theorem, its demonstration was obtained by Jacobi, and communicated by him to his pupils in his lectures at KGnigs- berg in the winter of 1836-37 (ese his note to the Berlin Academy, already cited in Art. 17). These lectures have unfortunately never been published ; but Jacobi’s demonstration, from his criticism (see ibid.) on the first of those given ten years later by Eisenstein, appears to have been very similar to it. It is to Eisenstein that we are indebted for the only published proofs of the theorem in question. ‘That great geometer (so early lost to arithmetical. science—a victim, it is said, to his devotion to his favourite pursuit) has left us as many as five demonstrations of it; the two earlier based on the theory of the division of the circle; the three last, on that of the lemniscate. We proceed to explain the principles on which each of these two classes of proofs: depends :— 29. Biquadratie Residues—Researches of Kisenstein.—It is possible, as we have seen, to obtain a proof of Legendre’s law of Reciprocity by considera- ON THE THEORY OF NUMBERS. 257 k=p—1 tions relating to the function & Ge p denoting a real prime, and k=] eP—] x a root of the equation . =0. This function is a particular case of the e— well-known function (introduced by Gauss and Lagrange into the theory of s=p—2 the division of the circle) F(0,2)= 6*xv° , where 0 is any root of the s=0 » §p-i—] Alec ty 9, eof equation pe y a primitive root of the congruence #?-!=1, mod p, and 2 a root of the equation = =0. In the quadratic theory we assign to @ the value —1; in the theory of Biquadratic Residues we put 0=7, and are thus led to consider another particular form of the same function, viz. s=p—2 , P,.2)—.> 2a , p denoting a prime of the form 4n+1. s=0 30. The function F(6, 2) or F(@) is characterized by the following general properties; which have been given by Jacobi, Cauchy, and Eisenstein. (See Jacobi, Crelle, vol. xxx. p. 166; Cauchy, Mémoire sur la Théorie des Nom- bres in the Mém. de |’Acad. de l'Institut de France, vol. Xviii.; Eisenstein, Crelle, vol. xxvii. p. 269.) I. F(6, x*) =9—Indy* F (9, x), Ja II. F(@) F (6-1) =6 2 p, F(O3*) FG?) Il. F(@= ota) =v (6), where (0) does not involve x, and is an integral function of 6 with integral coefficients*. The function W(@) satisfies the equation IV. ¥(0) YO") =p. xP-1—] yo= “ee”, Lastly, let 6 be a primitive root of =O, and in the function let y be written for 6; then if m and x be positive and less than p-l, I V. Vy) = — Te tn), mod p; [Im denoting the continued product 1.2.3...m. Applying these equations to the particular form of the function F which we have to consider here, we find F(i) F(=i)=i' * p, wo=F=O, if 640-0) =i, and m=n=3(p—1). CF(@)]'=py(2)’, [F(—#)]'=p)(—)*, 1() Y(—2) =p, Y(y?-))==0, mod p. * In this equation @—-™ and 9—” are supposed not to be reciprocals. 1859. s 258 REPORT—1859., Let (i)=a+bi=p,; (—1)=a—bi=p,, so that p,p,=p. The con- gruence [ yi(2—) ]==0, med p, or a+byP—-)==0, mod p, involves also the congruence a+by*?-==0, mod p,; 4 e. y?—!)==2, mod p,; so that k (“) =i*, Hence we have, puttingys=f, med p, Pi/4 k=p—1/} F(i)= 2) ak—S§, k=! Pils _ k=p—1/k\s F(—i)= 3 (|) ater. k=1 Pi From these formule two cases of the law of Reciprocity are directly de- ducible. a. Let q be a real prime of the form 4n+3. Raising 8 to the power g, we have k=p—1 ; k=p—1 3 Si= 3 (G)= Dy (5 )2*=(4) T, mod q, by (1.). k=1 Pil k=1 ee Pils Multiplying by S, we find pe pene pal Sash) pt p21) Fg (=) »mod q; yy L or, observing that p,=p,’, mod g, and p=p, p,, q?-1 pol St (up af ; t'.at is to say, (2) =(=4). <0) ite ied geen bees 4 174 which is in accordance with the law of Reciprocity. f. Again, let g be a prime of the form 42+1; 3 3 ee (12=(Z) s, mod g; that is, S7-"=(), mod g Pi/* Pils se Ma 1 3 ot pnp ser=(Z), mod g; Ti/4 whence, if g=¢, J» e)(B)-(8) W/s\NSi \Pils 3 3 But, by changing 7 into —2. (2) =(2), and (4) -(4), ‘hee tee qt G2 /1 Py/ P2/4 so that (2) =(4) . gs Jel of 6 so 4) bs | Shee ea The symbolic equations (A.) and (B.) lead immediately to the conclusion that if@ and } be any two primary uneven numbers, one, at least, of which is real, we have (5) =(*) ; and that if a@ and 6 be both real, the common value 4 Ma ON THE THEORY OF NUMBERS, 259 of these symbols is +1. By combining with these results the supplementary equation (ssa) =i-#(4-)), in which @+éa' denotes any primary uneyen 4 number, and also the self-evident equations, e(at+bi)=(ae-+-bd) +bi(e+di) a(etdi)=(ae+ bd) +di(atbr), at+bi =) iby (pai Gas tee" Kisenstein* investigates a relation between the symbols (35) and + e+d e+di ' ; : athe a+bi),’ which, when a+6¢ and e+di are primary, coincides with that ex- : 4 pressed by the law of reciprocity. 31. The proof in Eisenstein’s second memoir+ is identical in its essential character with that in the first; but he has given it a purely arithmetical form, independent of the theory of the division of the circle. Instead of the BR LEN opto 7 wl sum S= —) x*, in which @ is a root of the equation a 4 io =0, k= 71 k=p—1 he considers the powers of the series 3% G) , and arrives by a process k=1 — purely arithmetical at the eqtations (A.) and (B.) of the preceding article, Thus the two forms in which he has exhibited his demonstration are pre- cisely analogous to the two expressions which he has given to Gauss’s sixth demonstration of Legendre’s law (see above, Art. 21). $2. The proofs of the Law of Biquadratic Reciprocity, which are taken from the theory of elliptic functions, no less than those which we have just considered, depend in great measure on a generalization of the principles intro- duced by Gauss into his demonstrations of Legendre’s law. Indeed, Gauss himself tells ust that his object in multiplying demonstrations of Legendre’s law, was that he might at last discover principles equally applicable to the Biquadratic Theorem. It would be interesting to know whether the proof which he ultimately obtained of this theorem depended only on the division of the circle, or on elliptic transcendents. Jacobi appears to have believed the latter ; for he expresses his opinion that his own demonstration of the Biqua- dratic Theorem was widely different from that of Gauss§; and he further conjectures that what induced Gauss to introduce complex numbers, as modules, into the theory of numbers, was not the study of any purely arith- metical question, but that of the elliptic functions connected with the Lem- niseate Integral |. ‘his opinion of Jacobi’s will not appear im- dx L JV¥U-2"') * See the memoir entitled “ Lois de Réciprocité,” in Crelle, vol. xxviii. pp. 53-67. + “ Kinfacher Beweiss und Verallgemeinerung des Fundamental-Theorems fiir die biqua- dratischen Reste,” in Crelle, vol. xxviii. p. 223. { See the memoir, “ Theorematis Fundamentalis Demonstrationes et Ampliationes Nove,’ p- 4, “ Hoc ipsum incitamentum erat ut demonstrationibus jam cognitis cirea residua qua- dratica alias aliasque adderé tantopere studerem, spe fultus, ut ex multis methodis diversis una vel altera ad illustrandum argumentum affine aliquid conferre posset.” § “Ueber die Kreistheilung,”’ Cretle, vol. xxx. p. 171. bei vol. xix. p. 314, or in the ‘Monatsbericht’ of the Berlin Academy for May 16, s2 260 REPORT—1859. robable, when we remember that in the ‘Disquisitiones Arithmetice’ (Art. 335) Gauss promises an “amplum opus” on these transcendents; and that a casual remark of his in relation to them renders it perfectly certain (as Dirichlet has observed)* that he was at that early period in possession of the principle of the double periodicity of elliptic funetions—thus antici- ‘pating by twenty-five years the discoveries of Abel and Jacobi. Nevertheless the close analogy we have endeavoured to point out between Gauss’s sixth proof of the quadratic theorem, and the trigonometric demonstration of the biquadratic one, may perhaps incline us to the opposite opinion. Nor is the introduction of complex numbers, as modules, an idea unlikely to have sug- gested itself, when once complex numbers were admitted; though it is remarkable that Jacobi, in the first printed memoir in which complex num- bers appear, and to which we shall presently refer, seems not to have thought of this extension of his theory. 33. Application of the Lemniscate Functions to the Biquadratic Theorem. —Let p, be a complex prime (real or imaginary), p its norm; and let the —]1 residues, prime to p,, be divided into four groups of 3(p—1) terms, after the following scheme :— (0) r, UA) Cfo ioiee enchoic T3(p—1)s 6D ON aOR 7 ee eae ome 23(p—1)s (2) = Tis Brey «(0 eins eee s10 a Tx (p—1)» (3) —ir, —ir, ee ee ee eee —IP3(p—1)) so that of any four associated numbers one, and only one, appears in each group. Let g, be any residue prime to p,; &,, #,, k,,... the numbers of the residues Nn i 9, 73(p-1) which belong to the groups (1), (2), (3), respectively ; then gh (P—Yaaik 2h 3h, mod p,, = (@ ) = gh, t+ 2hy+3hs, Pi/4 (See Gauss, Theor. Res. Biq. Art. 71.) The expression on the right-hand side of this equation may now be trans- formed by means of the Lemniscate function ¢, defined by the equations mage ten The function g(v) is doubly periodic, the arguments of the periods being wo (') de 2 \ Va—=)3 so that we have ¢(v+2kw)=¢(v), & denoting any complex integer what- ever. From this it appears that the relation of the Lemniscate functions to the theory of complex numbers, is the same as the relation of circular func- Qw and Ziw, or, more properly, (1+7)w and (1—7)w, where * Tn his § Gedichtnissrede iiber Karl Gustav Jacob Jacobi,’ Mém. de l’Académie de Berlin, 1852. This remarkable éloge is also inserted in Crelle’s Journal, vol. lii., and in a French translation in Liouville’s Journal, vol. ii. 2nd series. t See Eisenstein’s memoir, “ Applications de l’Algébre a l’Arithmétique transcendante,” in Crelle’s Journal, vol. xxx. p. 189, or in Eisenstein’s ‘ Mathematische Abhandlungen,’ p. 121. ON THE THEORY OF NUMBERS. 261 tions to the arithmetic of real integers. The function ¢(v) also satisfies the equation (iv) =i*9(v), whence = a) “Cece. eeteaas ae 3 < pte ( ) the sign of multiplication II extending to every residue r included in the group (0). Similarly, if ¢,, like p,, be a prime, 119(*) ghit2hat Bhs Pr niy( 2") Pr) = PG eee 4 Ws wy 22) Br s denoting the general term of a quarter-system of Residues for the mo- dulus q,- g(kv) (v By an elementary theorem in the calculus of Elliptic Functions, is for every uneven value of & a rational and fractional function of «= 9(v). : ‘ 2rw If p, be primary, as we shall now suppose, and if we put w="), we have, by the principles of that calculus, : o(pw)_ Ti(2*—a') g(v) Wain" the sign II extending to all the different values of «,; and similarly, 9(9.2) _ Tap) . . . . . . . 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SU} eves “patoq uo [209 “diay Yona “sd, “powtod +[assa,A Jo amEN “SLTVULI YT Aq UMOYS 8B [v}0,T, Suripnpout ‘junoooy [exsusayH] *syZUOUL XIS 917} IO [C}0, suo} Jo gaquinu aseraAy | J° ‘ON SCS] OUNL YIOY Sulpua syjUOPY XIG aq} ACJ [LOD Jo uoyduNsuo|D "TL TIAV— (panwyuor) *A XidNdddy 281 ON STEAM-SHIP PERFORMANCE. & c Wd ‘ Wad ‘“ paanre v cT 61 LI ¢ W'd 0F-6 W'd 91-6 Wore 62 -se aq uvo su avout s0 10 waoyssury | puousioH | “658 a es it ca 82 Wd 86.0 WV 01-6 81 g SU} GI ***"BIPsUy peoy slop] UMOISSULY "1A. } SANOTTOS ee ¢ “W'd 9.0T ‘W'd €¢.9 Le rat as se it noM jt ‘Sol Donat ‘eae gene UMOJSSUTST peoyslopy ioy Sujonpap saqye puv‘6Fsi PEE “Wd TP-0 “WY 1-6 “7 jess By00g Sine 418 0} Spat Catan proysjoqy UMOpSSUTY S[ WO1f ISVIBAT S,1v9A hte Bae foe es $suinjor asaqy 53 FL 91 cl ce ¢ W'd 2.01 W'd ¢¢-9 “ 9L a jo potied ay} ye paystuany UMOJSSULY peoyAjoxy you seas diy cal powimnsuo0d re fe “ GF-0 cae “og “ A 3 +Aja0 c BPO AON Wody axe Sogo Ty ae € “ ThO an: ydag T ‘ $30] S JovUIsuy JO SUIIOJ OY, €€¢ Wd FFP-0 “N'Y TI-6 ‘Sny Oy eo ter aa vysuy wy peoysjoy] | umoysfury "SP8I ; *ysoMory “ysoy StH pane WOUpAs qe [eAWIy wo ainjredaq CeSTIE *ropulfAd qe sopeid Jo "98 *sasusstd a7eq *yeog jo ouryy SHAVUII s z te *10yVOIpuy 10 aBnes-uiva}g ps TMA, jo qysuey jo our, ‘oxy ‘sanoy £¢g ur s}eoq-weazg ay} Lq ape sadesseg Jo uNnjoY Y—Pl ITAV], ‘soy £9 0} paytutty afessed jo oumty ‘apes, spood ayy, Bie : L 8 99. 6. 0 Lo SO T€-01 8228s 8 0 Gc & ae aug él 89) €=7 40 nn a) 69-61 0C8 02 £8 0 Gc &F vette ga NU | ae! 92 -€ 0 Oh ie 0 cL-FT Z65‘L01 $8 1? 9 Tes ee meas Il Olt ¢@ O Co te 0 1¢-FI FF6 COL _8 hee Paeee ee Ae a 46 @&G O 8 USCOO 19-F1 991'SII T8 ee SOLS Ey Ulpsuy “Sq "SqT ‘JMO *St0} *"sq[ ‘jo ‘su0} Sq[ ‘Jao “su0} bs|-{quo 3 ‘ ae Syed | ‘ ‘una $9 ey aoc *sagtiog ur yout aivnbs!*ATuo Surauns ur ayrur) ‘urvays dn 3ury3a soytur 93n4e4s ‘In0y Und soyTUt Suratoovad a10joq unr | sdaplog Jo yyZIeA, | *]a8SaA JO aWUTNT od oinssaig uveyy | ad poumsuod speog | Surpnpout ‘apm sed | sad paads Jo ayey | angus Jo JequiNN’ | coins ¢ Jo xaquin yy : pauinsuod s[vop . ‘s10[10g UT aanssarg WIIG ‘pray A[oF] pu UMOJsSUTy ye Surd] ‘sory Surqueq ‘ea3g Surster yoy pue qytas ‘epiut sad yeog yo uondumnsuod pur ‘unas soplu JO JaquInu ‘s1a}log eu pey , BIUIEqIFy , pue ‘eyoog, “wuqueg, “eSuy, ay} alojaq uns sivak Jo Joquinu ay} Surmoys uinjay Y “S| TIaV,[—(panuyuoo) *\ XianNaaay 282 REPORT—-1859. AppPENDIX V. (continued).—TABL¥ 15. Mileage run, and expenses per mile, of the Passenger Boats in the years 1849, and 1856, 1857, 1858. 1849. 1856. 1857. 1858. Miles run ..........0000 39,910 40,885 52,910 40,040 i= ns Per Per Per Per Expenses. Total. iil. Total see Total. shile Total. iiley £ s. d. Gy) sed. Sigal eetls | sid. WIAGESS. saearesavhwenese oss 8,294) 42 | 5,461) 28 | 5,736) 22 | 5,160] 2 62 Coal erties 5,420} 2 83) 5,554] 2 84 | 6,387) 25 | 4,854] 2 2 Engine Stores, Ship j ; rl Stores, and Repairs 4,890] 2 53 3,017} 1 83 | 3,592) 1 44 | 2,540} 1 34 Harbour Light Dues...| 1,609} 0 9% 321) 0 2 431] 0.2 318] 0 2 General Charges ...... 425) 0 23) 595) 0 34 | 1,816] 06 | 1,172} 07 Doatiile-smpeieiebte 20,638] 10 4 /15,448| 7 63 |17,462| 6 74 |13,544] 6 9 | VI. *,* The numbers in the Returns given below correspond with the numbers of the columns in the Trial Form of Return. (See Table opposite page 274.) Return of Particulars respecting the Steam-ship ‘Anglia’ whilst under Trial. 1. Between Holyhead and Kingstown, six trips, 29th of September to 3rd of October, 1854. 2. W.S.W. to N.N.W.; fine, moderate; tides favourable. 3. 2 tons, 16 ewt., 102 lbs. 4. 12 tons, 13 ewt., 3 lbs. per trip. 5. Not ascertained. 6. 729°70 to 891°76. 7. Paddle. 8. Seecolumn 1. 9. See column 1. 10. 14°94 statute miles. 11. 187 ft. 10 ia. 12. 186°25 square feet midsection. 13. 9 ft. 14. 620. 21. Diameter, 24 ft. 6 in.; length, 9 ft. 6 in.; breadth, 3 ft. 8 in.; thickness, 4 in.; number, 12. 29%. Patent; modification of Morgan’s Patent. 23. About 22 tons. 24. 5 ft.2in. 26. Maudsley, Sons, and Field’s Double Patent Cylinder. 97. 48} diameter. 28. No. 29. Four. 30. Two copper cylindrical, each 444 cubic feet. 31. Two, each 14 cubic feet. 32. Circular. 33. Notascertained. 34. 25 revolutions. 35. Not ascertained. 37. 330°52. 38. 729°70 to 891°76; mean, 816°07. 39. 13}to15. 40. 25to 25}. 41. Two. 42. Tubular. 43. See column 45. 44. Weight of boilers, 40 tons, 19 ewt., 1 qr., 20 Ibs. ; weight of water, 35 tons. 45. The boilers are now removed under which trials were made. The plans in the hands of the builders. 46. Twelve. 47. See column 45. 48. See column 45. 49. See column 45. 50. See column 45. 51. See column 45. 52. Tubular. 53. See column 45. 54. Two, 5 ft. diameter. 55. Fifteen. 56. 5580 Ibs. Return of Particulars respecting the Steam-ship ‘Cambria’ whilst under Trial. 1. Between Holyhead and Kingstown, six trips, 22nd to 26th of May, 1856. 2. S. to E.; windy and fine; tides favourable. Three trips. 3. 2 tons, 19 ewt., 1lb. 4. 13 tons, 14 ewt., 1 lb. 5. Not ascertained. 6. 806°36 to 1174°80. 7. Paddle. 8. See column 1. 9. See column 1. 10. 14°07. 11. 19ft.9in. 12. 201 sq. ft. 10in. 13. 8 ft. 10}in. 14. 840. 21. Dia- meter, 28 ft.; length, 7 ft.; breadth, 4 feet; thickness, 4 in.; number, 16. 92, Ditto, 23. About 23 tons, 10 ewt. 24. 5 ft.10in. 26. Side lever, ON STEAM-SHIP PERFORMANCE. 283 27. 734. 28. No. 29. Two. 30. Ordinary. 32. D. 33. Not ascer- tained. 34.23 revolutions. 35. Not ascertained. 37. 392°10. 38. 806°36 to 1174°80; mean, 995°35. 39. 144 to 15}. 40. 244 to 27. 41. Four. 42. Tubular. 43. See column 45. 44. Boilers, 66 tons; water, 60 tons. 4.5. The boilers are now removed under which trials were made. 46. Twelve. 52. Tubular. 54. Two, 5 ft. diameter. 55. Fifteen. 56. 5760 lbs. Return of Particulars respecting the Steam-ship * Scotia’ whilst under Trial. 1. Between Holyhead and Kingstown, six trips, 17th to 21st of May, 1855. 2. S. to N.E.; light winds and fine; tides partly unfavourable. 3. 2°17. 4. 13:10. 5. Not ascertained. 6. 861°84 to 100716. 7. Paddle. 8. See column 1. 9. See column 1. 10. 15°68. 11.192°7. 12. 188°78. 13. 8°10. 14. 680. 21. Diameter, 24 ft. 6 in.; length, 10 ft.; breadth, 3 ft. 8 in. ; thickness, 3 in.; number, 12. 22. Patent; modification of Morgan’s Patent. 23. About 23 tons. 24. 6 fir. 26. Maudsley, Sons, and Field’s Double Patent Cylinder. 27. 52. 28. No. 29. Four. 30. Two copper cylin- drical, each 51 cubic feet. 31. Two, each 164 cubic feet. 32. Circular. $3. Notascertained. 34. 24 revolutions. 35. Not ascertained. 37. 379°92. 38. 861°814 to 1007°16; mean, 93418. 39. 12to 121. 40. 264 to 27. 41. Two. 42. Tubular. 44. Boilers, 47 tons, 3 cwt., 2 qrs.; water, 39 tons. 45. The boilers are now removed under which trials were made. 46. Twelve. 52. Tubular. 54. Two, 5 tt. diameter. 55. Fifteen. 56. 6240 lbs. Return of Particulars respecting the Steam-ship ‘ Telegraph’ whilst under Trial. 1. Between Holyhead and Kingstown, two trips, 29th of May, 1857. 2. S.W.; moderate and fine; tides partly favourable. 3. 2 tons, 18 ewt. 4. 15 tons, 8 ewt. 5. Not ascertained. 6. 1165°98. 7. Paddle. 8.\See columnl. 9.. See column 1. 10. 15°24 statute miles. 11. 243 ft. 8 in. 12. 294-70 sq. ft. 13..9 ft. Sin. 14. 1173. 21. Diameter, 26 ft. 10 in.; length, 10 ft.; breadth, 4 ft.; thickness, 34 in.; number, 14. 22. Patent; modification of Morgan’s Patent. 24. 4 ft. 5 in. 26. Side lever. 27. 774 diameter. 98. No. 29. Two. 30. Ordinary. 32. D. 33. Not ascertained. 34. 25 revolutions. 35. Not ascertained. 37. 448°0. 38.1165°98. 39. Four- teen. 40. Twenty-six. 41. Two. 492. Tubular. 44. Boilers, 70 tons; water, 65 tons. 45. The boilers are now removed under which trials were made. 46. Twelve. 47. Tube surface, 7382°76; furnace, 462°0; fame boxes, 747°0. 53. Number, 1128; length, 6 ft. 9in.; diameter, 32 iv. brass. 54. Two, 5 ft. diameter. 55. Fourteen. 56. 7800 lbs. Return of Particulars respecting the Steam-ship ‘ Mersey’ whilst under Trial. 1. Stokes Bay, 21st of April, 1859. 2. N.W. 4; smooth; ebb tide. 3. Not known. 4. Not known. 5. Notknown. 6. 1088. 7. 301. 8. Mean, 2 runs, 13°459 knots. 9. Mean, 2 runs, 13°117 knots. 10. 13°288 knots. 11. Length, 254 ft. 5 in.; breadth, 30 ft. 12. 261. 13. 10 ft. 5 in. aft; 10 ft. 1 in. forward. 14. 1300. 21. Diameter, 2! ft. 4 in.; length, 8 ft.’ 6 in.; breadth, 3 ft. 5 in.; thickness, 3 in. 22. Feathering. 23. 134 tons. 24. 4 ft. 25. Nottried. 26. Oscillating. 27. 60 in. diameter; length of stroke, 5 ft. 28. Steam belt. 29. Two. 30. Ordinary. 31. Ordinary bucket pump. 32. India-rubber valves. 33. 81 tons. 34. 3024 feet, 301 revolutions. 35. Unknown. 37. 250. 38. 1088, 39. 20 Ibs. full. 40, 284 REPORT—1859. Per Maudsley’s foreman, Condenser, 254 in.; but 26 starboard and 26} port engines, by our engineers. 41. Four. 42. Tubular. 43. 8 ft..2 in. by 10 ft. 6 in.; 13 ft. Gin. high. 44. 75 tons without, 120 with. 45. 1125 steam room, 1620 water room. 46. Eight. 47. 178 ft. grate surface, 4400 tube surface, 1007 other surface. 48. 528 cubic feet. 49. 1 {t. 2 in. at front, 2 ft.6 in. at back. 50. 2 ft. 2 in. at front. 51. 30 square feet. 53. 864 brass tubes, 3 in. diameter, 6 ft.6 in. long. 54. Two chimneys, 4 ft. diameter. 55. 20 lbs. 56. Not tried—(Signed) H. V. Strutt, Examiner R.M.S.P. Co. Return of Particulars respecting the Steam-ship ‘ Paramatta’ whilst under Trial. 1. 7th of June,1859. 2. Variable; moderate. 3. Unknown. 6. 2940. 7, Paddle wheels. 8. 14008 knots. 9. 13°907. 10. 13°957. 11. Length, 329°5; breadth, 43°75. 12. 606°2 square feet. 14. 386%. 15. Centre of gravity of displacement, 3 ft. abaft middle of load line, and 8°41 ft. below. 21. Diameter, 38 ft. 6 in. over floats; ditto, 34 ft. 33 in. at axis; floats, 12 ft. by 4 ft. 6 in. by 5 in.; fifteen floats on each wheel. 22. Feathering. 23. 69 tons. 24. 6 ft.8 in. 25. Not tried. 26. Double cylinder. 27. Diameter, 68yin. 28. No. 29. Four. 30. Ordinary. 31. Ordinary. 32. Conical valves. 33.291 tons. 34.17 revolutions per minute. 35. Not tried. 37. 764. 38. 2940. 39. 17} lbs. gauge on boiler. 40. 26in.vac. 41. Four. 42. Tubular. 43. Length, 24 ft.9 in.; height, 21 ft. 11 in. 44. Boilers, 220 tons; water, 184. 45. Steam-room, 5292 cubic ft.; water- room, 6440. 46. Twenty-four. 47. Grate, 7 ft. by 3 ft. 64 in.; by 24 in, tubes, 14696 square ft.; furnaces, &c., 2564 square ft. 48. 2636 ft. in four boilers. 49. 2 ft. 50. 2 ft.6 in. 51. 127 square feet in the four boilers. 53. 2496 brass tubes; internal diameter, 31 in.; external diameter, 34 in. 54. Two, 42 ft. long, 6 ft. 8 in. diameter. 55. 17 Ibs. - 56. Unknown.— H. Y. Strutt, Examiner R.M.S.P. Co. Return of Particulars respecting the Steam-ship ‘ Lima’ whilst under Trial. 1. From Liverpool to Kingstown and back, May 20th, 1859. 2. Fresh breeze, northerly. 3. 3tons. 4. 11 tons,5cewt. 5. 270,000 lbs. 6. 1160. 8. 134. 9.121. 10.12. 11. Length on deck, 257 ft.; length between perpen. 251 ft.; breadth, 30 ft.; depth of hold, 17 {t.; depth to spar deck, 25 ft.4in. 12.302. 13. Forward, 11 ft.; aft,i2 feet. 14. 1345. 21. Dia- meter, 26 ft. over all; do. 25 ft. 2 in. over floats; floats, 8 ft. 2 in. long, 3 ft. broad, 2 in. thick. 22. Feathering. 23. 20 tons. 24. 4 ft. 96. Ran- dolph and Elder’s Patent Double Cylinder engines. 27. High-pressure eylin- der, 52 in.; low-pressure do. 90 in. 28. Yes. 29. Four. 30. Common. 31. 17 ft. 42. Short slide, 24 in. by6 in. 33. 200 toms. 34. 240 ft. 35. 100°. 37. 320. 38. 1150. 39. 24 ]1bs. 40. 28 lbs. 41. Two. 42. Tu- bular, superheated, 400° Fahr. 43. 12 ft. by 10 ft. 44. Boilers, 50 tons; with water, 68 tons. 45. 1000 cub. ft. 46. Six. 47. Grate, 136; steam, 1700; heating, including uptakes, 1500. 48. 480 ft. 49. 2ft. 50. 2 ft. 6 in. 51. About 50 ft. 53. 258 iron tubes, 4 in. internal, 41 in. external. 54. One, 5 ft. diameter. 55. 27 cwt. 56. 25. Return of Particulars respecting the Steam-ship ‘Admiral’ whilst under Trial. 1. Between the Cloch and Cumbrae Lighthouses, Frith of Clyde, distance 13°66 knots, 11th of June, 1858. 2. Tide, quarter ebb, favourable for, 13°66 knots; half ebb, adverse for, 13°66 knots. 4. 2206 Ibs. per hour for 34 ON STEAM-SHIP PERFORMANCE, 285 hours. 6. 744. 7. Paddles, 3303 in 2°305 hours. 8. 12°65 knots, or 14°55 miles. &. 11°15 knots, or 12°82 miles. 10. 11°9 knots, or 13°69 miles. 11. 210 by 32. 12. 214 square ft. 13. 7 ft.6in., both. 14. 820 tons. 21. Diameter to Journals, 20 ft. 6 in.; 11 floats, 7 ft. long, 3 ft. broad and thick. 22. Feathering. 26. Double Cylinder. 27. Large, 4 ft. 3 in. aeaalee: 7614 in. diameter; Small, 4 ft. 3 in. stroke, 485 in. diameter. 28. Steam-jacketed. 29. Four. 33. Engine and Boilers, 210 tons. 34. 24 re- volutions. 38. 744. 39. Average, boiler 25 lbs., cylinder 19 lbs. 44. See column 33. 47. Grate, about 100. 56. 2206 lbs.— Certified by W. J. Macquorn Rankine. Return of Particulars respecting the Steam-ship ‘Emerald’ whilst under Trial. 1. Ayr ies July 21,1859. 2. Still water, light airs. 3. 30 cwt. 4. 133 cwt. 5. Not eu 7. 80 per minute. 8.12 miles. 9. No tide. 10. 12 statute or 10; knots. 13. 10ft.forward and same aft. 14. 150. 16. Diameter, 9 ft.; 3. ‘blade; pitch, 14 ft.; area of blade, 20 ft. 17. 18 in. 18. 33 ewt. 19. Not known. 20. Not Pace 26. Horizontal. 27. Length of stroke, 22 in.; diameter, 28 in. 28. No. 29. Two. 30. Common condenser, contents not known. 31. Trunk, 3476 cubic inches. 32. Com- mon slide valve. Area not known. 33. Not known. 34. 2934. 35. 95 degrees. 36. 56ft. 37. Eighty. 38. Not known. 39. Not known. 40. Vacuum in condenser, 234 in. 41.One. 42. Tubular. 43. Depth, 11 ft.; length, 94 ft.; breadth, 133. 34. Not ascertained. 45. Not known. 46. Four. 47. 1313 ft. 48.198 ft. 49. At door, - in.; at back, 26 in. 50. At front, 26 in.; at back, 19 in.; mean, 223. . 1744. 52. Boiler tubular. 53. 270 iron tubes, 64 ft. long ; exterior Ae ee ; interior, 24. 54. One, 26 ft. by 4 ft. diameter. 53. 133 lbs. 56. 133 ewt. Continuation of Taste 1, AppENDIx VII. For Mean Speed. eek EN Se ee Rigutiealelcs Half wof Sh “a a | Uitterenees Difference. 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(continued.) Table 4.—Experiments with Yacht ‘ Erminia,’ October 12, 1858, in Stokes Bay. Draft forward, 9 ft. 3in. Immersion of periphery, 2 ft.6 in. Diam.of cylinder,15in. Stroke,18in- Draft aft, 12 ft. 11in. Area of midsection, 149°18 sq. ft. Diam. of screw, 8 ft. Pitch, 13 ft. g)8/ @ |as af arg oR Pe eee Rate i & 2 Es |€&8 4 ae & 2 wéatate smiles sanceeal masles Spooks Al s we icslee | sé 1 A A alk Sed : : Remarks, S| 4 an |os) oS) BY | ee -| ¢ FF] eB) og | = 5. 3| 8 4 As| Ag f& @ | Ship. |Screw.| Ship. | Screw.| Ship. | Screw. Ibs. | lbs pepe ly Me 1 | 53 | 36:2 » 3 ¥ Fe oe : . Senge gainst win 2 | 53 | 32-7 743 | 54:03 59-98! 37-1 | 4°95! 7-98} 4:36] 6°92 | 442-4) 702-39 aah tide. 3 | 53 | 28-7 Peers MR ooh as Bete el aaa ity Lue lara. | f With wind Be i laos } 416| 51-8 | 48-26 10:8 | 8-62) 7-65) 7-44| 6-64 | 754-4 673-4 [1 NOt Wn 5 | 50 | 34:16 Baltece : ; : : : : : Against win 6 | 53 | 32-0 615 | 53:4 | 58°68 23°86) 5-91} 7°88} 5:21] 6°84 | 528-6) 694°2 vail Gite. 7 | 50 | 32-77 DB OSA EEA AGA Ad Be | ana.a4| f With wind 8 | 50 | 30-94 440 50°28 51-44 6:2 | 7°87| 7°42] 6°85 | 6°44 | 695-1] 653-64 aud tdel Report of the Proceedings of the Balloon Committee of the British Association appointed at the Meeting at Leeds. THe Committee met at Burlington House, London, on the 29th November 1858: present— Colonel Sykes in the Chair, Lord Wrottesley, Dr. Lee, and Mr. Gassiot on the part of the Kew Committee. Mr. Gassiot read the resolution of the General Committee appointing the Balloon Committee ; namely— “ That Colonel Sykes, Lord Wrottesley, Professor Faraday, Professor Wheatstone, Dr. Lee, and Professor Tyndall, be appointed a Committee to confer with the Kew Committee as to the expediency of arranging further balloon ascents, and (if it should be judged expedient) to carry them into effect ; and that a sum of £200 be placed at their disposal, if it should be required for that purpose.” Mr. Gassiot, as Chairman of the Kew Committee, reported that, in con- sequence of the severe indisposition of General Sabine and of Mr. Welsh, he had not summoned the other members of the Kew Committee to attend this meeting. Colonel Sykes read letters from Sir John Herschel and the Astronomer Royal, approving of further balloon ascents. The question of expediency was discussed; and it was resolved, in con- sequence of the absence of three members of the Committee, and General Sabine and Mr. Welsh, to postpone the further consideration of the subject until the next meeting of the Committee, to be summoned by the Chairman. Burlington House, 27th May, 1859. Present, Colonel Sykes in the Chair, Lord Wrottesley, Professor Faraday, Professor Tyndall, and Dr. Lee. 3 Resolved,—That it is expedient for scientific objects that balloon ascents be renewed, due care being taken for the safety of the aéronaut, and the competency of the agents employed. (1859. U 290 REPORT—1859. Resolved,—That Mr. Green be invited to meet the Committee at the next meeting. Resolyed,—That Admiral FitzRoy and Mr. Glaisher be added to the Committee. Burlington House, 15 July, 1859. Present, Colonel Sykes in the Chair, Lord Wrottesley, and Admiral FitzRoy. © Read a letter from Professor Tyndall, regreting his inability to attend the meeting, but offering his services to ascend in the balloon, and assist in the observations. Mr. Green attended, and stated that himself and his balloon were at the disposal of the Committee whenever called for. Colonel Sykes reported that the following gentlemen offered their services to ascend with the balloon as observers: Mr. E. B. Russell, and Mr. John Murray, students of medicine in Glasgow University, Mr. Storks Eaton of Dorsetshire. Resolved,—That Colonel Sykes apply to the Chairman of the Kew Com- mittee to have the instruments used in the former balloon ascents prepared for immediate use. Resolved,—That Colonel Sykes be authorized to make the necessary arrange- ments with the several parties to be employed, preparatory to ascents which may take place either from Birmingham or Wolverhampton. Consequent upon the above resolution, Colonel Sykes arranged the terms of compensation with Mr. Green for four balloon ascents—the first £30, the second £25, the third £20, and the fourth £15, the Committee paying for gas, and all incidental expenses. Lord Wrottesley was good enough to obtain a supply of gas from the Wolverhampton Gas Company, the use of their yard for the ascents, and the cordial assistance of their people. Monday, the 15th of August, was fixed for the ascent ; and Mr. Storks Eaton, who had previously taken charge of, and made himself familiar with, the instruments, offered his gratuitous services to go up in the balloon. Lord Wrottesley, Admiral FitzRoy, Mr. Glaisher, and the Chairman as- sembled at Wolverhampton, at 1:30 p.m., to superintend the ascent. The weather was fine, but the wind came in gusts; the inflation, however, com- menced; but the balloon filled slowly, and when 63,000 cubic feet of gas had been introduced, the evening was fast approaching ; and as doubts were ex- pressed of the ascent being made in safety, in consequence of the wind, the Committee resolved to defer the ascent until the following day. On Tuesday, the 16th of August, the Committee assembled at 1:20 P.m.; the balloon had been completely inflated; but as the Committee were entering the Gas Company’s yard, a gust of wind occasioned the neck of the balloon to flap so violently, that a rent of some yards was produced, and the gas escaped rapidly. This untoward accident stopped all further proceedings ; and as Mr. Green said that the balloon could not be properly repaired within many days, as the balloon had received other injuries, the Committee were compelled to forego any attempt to effect balloon ascents before the ap- proaching meeting of the British Association. The Committee having thus reported their proceedings, recommend the reappointment of the Committee to carry out the objects which an accident has frustrated; and the Committee look to the concurrent cpinions of the distinguished men who have expressed themselves favourable to further balloon ascents, having their due weight. The Committee cannot close their report without expressing their oblig - tions to the Mayor of Wolverhampton, Mr. John Hartley, and to the Di- ON THE SOLUBILITY OF SALTS. 291 rectors of the Gas Company, for their courtesy and cooperation. The thanks of the Committee are particularly due to Lord Wrottesley for his active and efficient aid, and for the reception of the Members under his hospitable roof at Wotesley Hall. W. H. SyKxEs, London, 20th August, 1859. Chairman. P.S.—Mr. Green not having fulfilled his engagement, was only paid his RESPONSES olor Sie ue nist me cain ee pa ness £7 511 BI is gia on Re a es ta) Expenses of Pat TEES eee tek ani 127. 0. 2 Mr. Eaton’s carriage of instruments andether 113 6 (6 Pittal ae tert. dacs Mea cis xide upg eae Preliminary Report on the Solubility of Salts at Temperatures above 100° Cent., and on the Mutual Action of Saits in Solution. By Wiuuram K. Suniivan, Professor of Chemistry to the Catholic University of Ireland, and the Museum of frish Industry. NorwitusTanpbincG the evident importance of the phenomena of solution, not only in a purely physical and chemical point of view, but also in con- nexion with many of the most interesting geological and physiological phe- nomena, the subject, until recently, seems to have been almost altogether neglected, as if by common consent. Our knowledge respecting the solu- bility of any given substance in certain liquids, was usually comprised in such expressions as “ soluble,” “ very soluble,” “ difficultly soluble,” &c.—I might even say, is now comprised; for the law of solubility in water up to the tem- perature of 100° Cent. can scarcely be said to be known for a dozen salts, and has not been at all determined for higher temperatures or for other solvents. Since the admirable experiments of Gay-Lussac, by which he established the law of solubility of Glauber-salt, many important investigations, bearing upon the subject of solution, have no doubt been published ; but, generally speaking, the immediate objects of these researches had to do with some other department of physics or chemistry, rather than with the establishment of a theory of solution. Among these I may mention Legrand’s experiments on the in- fluence of salts on the boiling-point, Frankenheim’s on the capillarity of saline solutions, the well-known researches of Graham on the diffusion of solutions, of Person, Favre and Silbermann, Andrews, &c., on the latent solution heat of salts, Playfair and Joule’s researches on atomic volume, and many others which it is needless to mention. Any experiments directly bearing on the subject which did happen to have been made with the view of determining numerical laws, were in general confined to the determination of the quantity of salt held in solution at different temperatures, and to the specific gravity of the solution. The range of temperature was usually limited to that between 0° and the boiling-point of the solvent, or to that of the dissolution. The uncultivated state of this important field of inquiry is no doubt to be attributed in part to the great labour required to work it, and the apparent insignificance of the results of even the most successful research. The recent laborious investigations of Léwel, Kremers, Gerlach, Wullner and others, show, however, that it is no longer likely to remain uncultivated ; and from the enlarged views of the general physical relations U 292 REPORT—1859. of the phenomena of solution which these experimenters exhibit, we may expect most important results from their labours. The graphic coordination of the results of experiments on the solubility of salts which have hitherto been recorded, lead to this capital fact, that within the limits of temperature embraced by the experimeuts, soluble salts may be classified into three groups :—1, those which, like sulphate of soda, attain a maximum of solubility within those limits, that is, give an ascending and descending curve; 2, those which, like common salt, have sensibly the same solubility at all temperatures within the limits; and 3, those which, like nitrate of potash and the majority of salts, increase considerably in solubility as the temperature rises. ‘The fact of certain salts, such as sulphate and carbonate of soda, exhibiting a point of maximum solubility, or, as Lowel has shown, several such points, according to the modifications which take place in their molecular states, naturally suggests the probability that most salts would exhibit a point or points of maximum solubility, and a descending as well as an ascending curve of solubility, if we were to extend the range of our experiments to sufficiently high temperatures, provided they could resist without decomposition or volatilization such temperatures. And further, that many salts more or less soluble at common temperatures, may become wholly insoluble at high temperatures. In the case of sulphate of lime, the latter fact has been established by the observations of M. Couche and myself. From some preliminary experiments which I have since made, I think I shall be able to establish it in the case of many other salts likewise. Although water under sufficient pressure retains its liquid form at tem- peratures far above 100°, the experiment of Cagniard de la Tour shows that if the temperature be raised sufficiently high cohesion will ultimately disappear, and the water will pass without alteration of volume into gas of enormous tension. Frankenheim and Brunner -have both found that the elevation of water in capillary tubes decreases with the temperature, and that it is capable of being represented by a very simple formula of interpolation as a function of the temperature. If this formula were to hold approx- imately true at very high temperatures, it would enable us to trace the diminution of the cohesion as the temperature rises, until it would wholly vanish, which on this hypothesis would take place, according to Brunner, at 535°°38. Cagniard de la Tour made similar experiments upon some other liquids with like results. He found that the total gasification of ether took place at about 200°. The temperature at which the capillary height of ether would be zero, calculated by Brunner’s formula, would be 191912. Wolf has experimentally found* that the capillary height was reduced to zero at 190° or 191°; above that temperature the capillary meniscus was below the level of the liquid, that is, there was capillary depression. At about 198° the strongly convex surface of the liquid appeared to cover itself with a thick cloud: at about 200° it was wholly changed into vapour. This striking coincidence between the calculated and experimental results, M. Wolf con- siders to be only accidental. Brunner’s formula was founded upon experi- ments made within the limits of temperature of 0° to 35°, a range which M. Wolf thinks too limited. He has found, that, although the law of Brun-’ ner, that the decrease of the capillary height is proportional to the tempera- ture, holds true up to 100°, it becomes more rapid above that point. _What- ever may be the exact law for high temperatures, enough has been done to show that the decrease of capillarity may be employed as a measure of the diminution of cohesion at high temperatures. I think we may safely con- * Ann. de Chim. et de Phys. vol. xix. p. 230. ON THE SOLUBILITY OF SALTS. 293 clude, both from Cagniard de la Tour’s experiments and the theoretical results of Frankenheim and Brunner, that at a red heat water would be completely gasified. If instead of pure water we subject a saline solution to a high tem- perature, what would be the result? Long before the solution would attain the temperature at which water would pass into gas of the same volume, it seems probable that a large number of salts would become insoluble, owing to the gradual diminution of cohesion between the molecules of water. If this sup- position be correct, the point of maximum solubility of a great many salts cannot be higher than 200° Cent. At very high temperatures water is capable of decomposing a large number of salts, even otherwise very stable double silicates ; but as this action appears to depend in many instances upon the mass of the water, saturated solutions of salts heated under pressure, are not so liable to be decomposed as when salts are exposed to a current of hot steam. If the salt did not become insoluble before the water reached the point of gasification, and that it was capable of resisting that temperature without decomposition, and was not per se volatile at a red heat, we may conclude from the slight affinity between gases and solids, as well as from many other considerations, that the water and salt molecules would completely separate. The singular anomaly which boracic acid offers of being volatile in the vapour of water, a property which the experiments of Larocque* show belongs to many other fixed substances, also indicates that possibly several salts may not precipitate on the passage of the water into gas, but remain attached to the gaseous molecules. Under such conditions of tempera- ture and pressure the most unforeseen phenomena may be presented to us. The study of the laws of solubility of salts at very high temperatures is obviously, then, of very considerable importance. In undertaking their investigation I did not underrate the difficulty of the subject, though perhaps I did its extent. The most superficial consideration will at once convince any one thata mere table of the quantities of salt held in solution at different temperatures would be of very little value; and that, to be of any use, the investigation should include that of the action of salts in solution upon one another at those high temperatures. Further, as the study of the solubility of salts at any given temperature is but a particular case of the general question of solution, every such investigation must necessarily deal more or less with the whole of the phenomena of solution. The problem I proposed to investigate, while apparently limited enough, involves in fact the study of a very considerable branch of the physics of molecules. In so extensive a field of inquiry, and especially where we have to deal with very complicate phenomena, the study of which is beset with practical difficulties, and even danger, the individual investigator cannot hope to reap a very large return for his labour, however successful he may be. Every one who has worked at such subjects will understand that considerable progress must be made in an investigation of this kind before the results admit of being coordinated. Notwithstanding many unexpected interruptions, I have devoted a good deal of time in preliminary experiments upon the best methods of conducting my researches, and in endeavouring to devise apparatus for the purpose. Even though my progress were very rapid, instead of being very slow, as it has been, I should not be in a position to bring before you on this occasion a report of any numerical results which I may have obtained. It is due, how- ever, to the Association to explain in a short preliminary report the point of view from which I am proceeding, and the extent and character of the field of research. As in so extended a subject any results obtained during the inquiry must be communicated piecemeal, such a preliminary report may * Journ. de Pharm. vol. xiv. p. 345. 994 REPORT—1859. serve hereafter the very useful purpose of linking them together and indicating their relative importance until a final report can be drawn up. In considering the subject which I propose to investigate, several questions immediately suggest themselves, which demand attention before entering upon the inquiry itself, as they relate to matters which constitute the ground- work of the whole subject. Of these I shall mention a few:—1. What is solution, and in what does it differ from fusion? 2. What special function does the solvent perform, and in what do water, alcohol, ether, and carbides of hydrogen differ in their solvent functions? 3. In what relation does water of crystallization stand to the other constituents of a hydrated salt? 4. When hydrated salts are dissolved in water, does the saline water still remain attached to the salt molecule, or does it mingle with the solvent? Or, in other words, in considering the physical properties of saline solutions, are we to regard them as made up of water molecules and anhydrous salt molecules, or as water and complex molecules of hydrated salts ? These questions have not been answered. No satisfactory hypothesis has even been proposed for the purpose. Neither can we hope to do so before the whole subject of molecular physics shall have considerably progressed beyond its present imperfect state. Still, although we cannot hope to answer those questions fully, they are so important in connexion with the special object of the present investigation, that they must necessarily be included as far as possible with it. Many are inclined to consider solution as a case of chemical combination. In adopting this view, we do not, however, solve the problem; but if suffi- cient grounds existed for adopting it, we may consider doing so a step in advance, inasmuch as it would save us from the necessity of inventing a new form of force. If the test of chemical combination be, that the combining bodies unite in definite proportions, solution appears at first sight not to pos- sess that characteristic. It appears to me, however, that we ought to di- stinguish two kinds of solution :—1, that of liquids in liquids; and 2, of solids in liquids. Some considerations founded upon the dynamical theory of heat may help us to understand this distinction. According to that theory, the molecules of gases are so far separated as to be beyond the sphere of their mutual attractions, and they are further con- sidered to travel onwards in straight linés according to the ordinary laws of motion. A gas may therefore freely flow into another, there being no cohe- sion between the molecules, and chemical attraction only when molecules which are strongly polar approach within the sphere of their attractive forces. In liquids, on the other hand, the repulsive action of motion is not sufficient to remove them beyond the sphere of their mutual attraction, notwithstanding that each molecule has not a determinate position of equili- brium, and may consequently freely change its place. The liquid molecules are, in fact, assumed to be in a state of vibratory, rotatory, and progressive motion, so that each molecule is not permanently attached to another; but the progressive motion is not sufficient to carry it beyond the cohesive influence of the others. We may assume that great differences exist in the character and velocity of the vibratory and rotatory motions of the molecules of different fluids. The fluids, the molecules of which possess the same character of motion, may consequently mingle, because the molecules of each will not interfere with each other’s motion. When the motions of the molecules of two fluids are incompatible, they do not mingle. The observations of Wilson and Swan upon the changes which one liquid produces in the form of the surface of contact of another, appear to support the view just stated. ON THE SOLUBILITY OF SALTS. 295 Although fluids whose molecular motions are not incompatible may be able to mix in the same indefinite proportion as gases, true chemical combi- nation may also take place between them. It is very easy to prove this in some eases, as, for example, when we add 27 parts of water to 63 parts of HO, NO,; because in this case we have heat evolved, and the mixture has a fixed boiling-point, and may be distilled without decomposition. In other cases it is not possible to prove it. Change of volume, accompanied by the evolution of heat, can scarcely be considered a proof, inasmuch as we would assume as true the very thing we have to prove, namely, that the conden- sation is due to chemical combination. In the case of a mixture of alcohol and water, there is a considerable condensation, which may, as some suppose, be due to true chemical combination. M. Vergnette Lamotte, for instance, states that in congealed wine the alcohol and water are in definite proportions in the frozen part, an opinion not, however, adopted by M. Boussingault and others. This condensation may perhaps be accounted for in another way, which, however, it would take too much space to develope fully here, but which I shall have a more fitting opportunity of doing hereafter. As the molecules of solids have a determinate position of equilibrium, their solution in any medium implies the exertion of a certain amount of force by the molecules of the liquid upon the solid. There is thus a distinc- tion between the solution of solids and of liquids; the former partakes more of the character of chemical combination. It may be that when a solid is dissolved in water. it forms in the first instance a definite chemical compound which is liquid, and may therefore mingle with the uncombined water. If this hypothesis were correct, it would account for the absence of stoichio- metrical relations between the quantity of salt and of the water in which it is dissolved, for a saline solution would be a compound of water and salt mole- eules mixed with quantity of water. Some salts may possess the property of forming several such liquid compounds, others, perhaps, only one. There is considerable analogy between solution in the ordinary sense, and alloys, especially amalgams. Mercury appears to be capable of forming an endless number of compounds with several metals, some of which are solid and others liquid. The solid alloys freely dissolve in mercury. In the solution thus formed have we the original alloy simply dissolved in the mercury, or has a new compound been formed? If we cool the mixture crystals often sepa- rate, which may or may not be the alloy originally dissolved, according as the conditions under which they are formed are the same or different from those under which the alloy was first formed; exactly as when a salt sepa- rates from its aqueous solution at different temperatures with different pro- portions of hydrated water. The proportions in which mercury combines with metals are so numerous, and so unlike those which we meet with among the compounds of the metalloids, that we are perhaps justified in concluding that a metal dissolved in mercury is always in chemical combination, and that when the constituents of an amalgam or of other liquid alloys are not in definite proportion, we may account for it by supposing that it consists of some liquid alloy mingled with 2 quantity of mercury. As an example of the proportions in which mercury combines with the metals, I may mention the alloys made by Crookewitt* :—KHg,,; KHg,,; Cd, Hg,; PbHg; BiHg; Ag, Hg,,; AgHg,; AgHg,; AgHg,; AuHg,. Among the other arguments which may be urged in favour of solution being reckoned as a case of chemical combination, I may mention—1, that saline solutions in HO have a fixed boiling-point, a point of congelation, and, like water itself, a point of maximum density ; and 2, that solutions are * Ann, der Chem, und Pharm, vol, Ixyiii. p. 259. 296 REPORT—1859. homogeneous. Some experiments of Bischoff and Debus led to the conclusion that gravity acted upon a solution of a salt and caused an accumulation of the salt molecules in the lower portion of a column of the solution. Lieben has, however, found that the solution of a single salt is perfectly homogene- ous. It yet remains to be proved whether saline solutions, containing a number of salts in solution, are homogeneous. But if we admit the homogeneity of salitie solutions, it appears to me that we must of necessity assume that in the solution the salt is combined with 2 molecules of water—z being variable according as the conditions of equili- brium are modified, or we shall be forced to admit the infinite divisibility of matter. There is an evident relationship between solution and fusion. Whena salt is fused, a quantity of heat is absorbed ; when dissolved in water, a still larger quantity of heat is in most cases absorbed. Thus, according to Person*, 1 gramme of KO, NO, absorbs 49 heat-units of latent fusion heat ; but if dissolved in 5 grms. of water, 69 heat-units are absorbed and 80 when it is dissolved in 20 grms. Whenever the same body is fused under the same pressure, the quantity of heat absorbed is always the same; but when a soluble substance is dissolved, the absorption of heat increases with the amount of water employed though not in a direct ratio. Even the dilution of a solution causes an absorption of heat; and with every success- ive dilution an additional quantity disappears, the only apparent limit being our means of detecting it. It is difficult to reconcile this phenomenon with that of homogeneity, unless we admit solution to be combination ; and even then there must be a limit somewhere, unless we consider matter infinitely divisible. The solution heat of a salt appears from the experiments of Person? to diminish as the temperature increases, a result which was pointed out by Graham, and which we might indeed have anticipated from the diminution of the specific heat according as the temperature rises, and from, as Person suggests, the specific heat of the saline solution being less than that of the separate constituents. On dissolving 1 grm. of chloride of sodium in 7-28 grms. of water at 70°, no absorption of heat was observed. Fusion, solution, and dilution are evidently but varieties of the same phenomena, and should be included together in any hypothesis framed to account for latent heat. MM. Favre and Silbermann proposed a very ingenious hypothesis to account for the latent heat of fusion: they considered it as the result of chemical combination or decomposition. They looked upon ice as isomeric water, n (HO), where z is any simple number ; when HO becomes z (HO), heat is evolved; when, on the other hand, ice melts, that is (HO) splits into HO, heat is absorbed. In the same way they looked upon a crystallized salt as an isomeric form of the same salt when in solution, e. g. SO, K, and §, O, K,,. This hypothesis would account for latent solution heat, which it would assi- milate to latent fusion heat; by a slight modification it may be made also to account for the latent dilution heat,—by supposing crystallized salts to be higher multiples than that above assumed in the case of sulphate of potash, which may be considered to be x (SO, K); and that when it is dissolved in a small quantity of water, it splits into two or more molecules of a lower isomeric body, and this again into others on further dilution. The modification here proposed seems to receive support from the discovery of a number of isomeric salts. For instance, Lowel $ has obtained two salts with the empiric formula NaO, CO,+7HO, of different solubilities, * Compt. Rend. vol. xxxi. p. 566. + Ann. de Chim. et de Phys. (3) vol. xxxiii. p. 448. } Ibid. vol. xxxiii. p. 334. . ON THE SOLUBILITY OF SALTS. 297 the one crystallizing in the form of rhombic, and the other in quadratic tables or Hat prisms. He has likewise obtained* a salt isomeric with common Epsom salt, MgO, SO,+7HO, and more soluble than it; it cry- stallizes in rhomboidal tables, which lose their transparency when taken out of their mother-liqnor. Marignac has shown? that the quadratic crystals of sulphate of nickel have the formula NiO, SO,+6HO, and that an isomeric salt crystallizing in the monoclinic system is formed at a temperature of from 50° to 70° Cent. Further researches will make us acquainted with many other examples of the same kind. The salts of manganese, cobalt, chrome alum, &c., present us with remarkable examples of molecular changes accompanied by striking changes of colour, in some of which we have true isomeric salts, as in the case of manganese, and in the case of chrome alum a difference in the amount of hydrated water. We should, however, distin- guish clearly between the molecular changes which give rise to the isomeric salts, and those which are accompanied by a total alteration of physical pro- perties. It is worthy of remark, too, that many chemists have been led, from wholly different reasons, to assume a more complex (as to the number of molecules) composition fcr salts and for chemical compounds generally. I may mention, for example, Avogadro’s view, that the equivalent of a sub- stance does not necessarily represent the relative weight of an integral mole- cule, but that the latter may be a multiple or an aliquot part of the former ; and Hunt’st, that all solid substances which have the same form, contain an equal number of atoms in equal volunies, a view which leads him to pro- pose such a formula as Na,, Cl,, for common salt. The existence of double salts of isomorphous bases containing a great number of equivalents of one combined with one or more of the other, and which are easily decomposed by merely dissolving them in a large quantity of water, is another circumstance which renders the hypothesis of Favre and Silbermann, and the application of it in a modified form above given, of increased interest. If we adopt the hypothesis that crystallized salts are isomeric compounds, and that solutions are unstable compounds of salt molecules and water molecules, it seems to me that the phenomena of crystallization and solution, and perhaps the whole phenomenon of the change of physical state of bodies, may be referred to the category of double decomposition. It would lead me too far to attempt to develope this hypothesis here ; indeed, without a good deal of experimental data to sustain my arguments, it would not be useful. I hope to be able to develope it fully on another occasion. I have mentioned it now, merely because it is intimately connected with the remaining questions which I have set down above, and which, with the exception of the fourth, I do not propose to discuss on this occasion. There would obviously be a wide distinction between a solution containing the molecules MgO, SO,+7HO, and one containing only MgO, SO,._ When we dissolve Epsom salt in water, which of the two solutions have we? The answer to this question depends to a considerable extent upon what may be the result of inquiries concerning the nature of solution. Ifa solution be a chemical combination between salt molecules and 2 molecules of water, the compound being liquid, and furthermore, if the crystallized salt be an isomeric form of the salt in solution, we must conclude that the water of the hydrated salt, as such, does not exist in combination with the salt mole- cule in solution, but becomes attached to it at the moment of the formation of the crystalline salt by a process of double decomposition. In assuming, * Ann. de Chim. et de Phys., vol. xliii. p. 405. + Liebig and Kopp’s Jahresbericht, 1855, p. 411. $ Silliman’s American Journal (2), vol. xv. p. 116. 298 REPORT—1859. however, that the formation of the crystallized salt is the result of double decomposition, we admit the existence of a specific molecular arrangement of salt and water in the solution, which under the same conditions of tempera- ture, &c. always yields the same salt. That such a molecular arrangement does in reality exist, is proved by the fact that the same salt crystalizes with different amounts of hydrated water according to the temperature, a good example of which is afforded by sulphate of manganese. The lower the temperature, the larger will be in general the quantity of hydrated water which attaches itself to the salt molecule. Even salts which usually crystal- lize anhydrous, such as common salt, frequently separate in a hydrated form from solutions at very low temperatures. A solution of common salt cooled to —10° yields transparent oblique rhombic prisms of the monoclinic system containing 4 equivalents of water. The large flat six-sided tables which Ehrenberg and Frankenheim observed to form under the microscope at the temperature of +15°, were most probably crystals of another hydrate. The formation of the double sulphates of the magnesian series is another striking proof of the pre-existence in a saline solution of a special molecular arrangement. ‘The equivalent of constitutional water in MgO, SO,, HO, 6HO is substituted in the double salts by an equivalent of an alkaline sul- phate; this substitution must take place by double decomposition, and so far supports the hypothesis that all ecrystallizations are due to that process. As the substitution takes place in solution, we must I think admit, either that the salt has this equivalent of constitutional water attached to it in solu- tion, or that some combination does occur there, which by double decompo- sition would give a crystalline compound in which it would exist. The existence of special molecular modifications in the constitution of salts, is assumed by Lowel to be the cause of the difference of solubility which the same salt sometimes presents at the same temperature, and not the amount of water which it takes up in erystallizing. This must necessarily follow as a relation of cause and effect if we adopt his view, that a salt is always pre- sent in solution in its anhydrous state. Such a view, however, compels us to admit that the salt molecule itself undergoes as many molecular modifica- tions as there are distinct hydrates, and this under the influence of very slight causes ; on the other hand, it does not satisfactorily account for the formation of such isomeric salts as those alluded to above, or for the effect of heat upon solubility. Gay-Lussac’s view, that the hydrated water of the erystallized salt remains attached to the salt molecule in solution, affords no more satis- factory explanation of the phenomena in question, while that which it gives of supersaturation—the inertia of the saline molecules—is wholly untenable. Lowel’s view, if we could account for the necessary molecular changes, would explain the phenomenon of supersaturation satisfactorily. It assumes that, strictly speaking, there is no such thing, and that solutions considered to be supersaturated merely contain salts having a different molecular consti- tution, and a different solubility from that ordinarily present at that tempe- rature. The hypothesis that solutions are unstable compounds of salt mole- cules and water molecules, and crystalline salts compounds formed by their double decomposition, affords a simple explanation of the molecular changes required for accounting for supersaturation; and it especially enables us to distinguish between the molecular modifications which give rise to isomeric hydrated salts, and those offered by the green and violet modifications of chrome alum—the former may be assumed to affect the arrangement of the molecules of water and salt in the unstable compounds in solution; the latter and more profound, the salt molecules themselves. Equal solubility does not necessarily imply that two salts are held by the ON THE SOLUBILITY OF SALTS. 299 solvent with equal force. It may be therefore that some salts do actually retain an equivalent of their water of crystallization attached to them in solution. Thomson’s experiments lead to the conclusion that the third mole- cule of water in terhydrated phosphoric acid is not held so firmly as the others. On the other hand, Gerhardt has shown that when three equivalents of the strong base soda are substituted for the three of water in terhydrated phosphoric acid, the salt formed, 3NaO, PO,, has the power of retaining an equivalent of HO at the temperature of 100° Cent., which can only be removed at a temperature approaching redness, while the salt 2NaO, HO PO,+24HO loses the whole of its crystalline water at 100°. It is probable that the equivalent of water thus retained, performs the same function as the constitutional water of the magnesian sulphates, and may be replaced by a salt molecule. Such salts as 3LiO, PO,+2LiO, HO, PO,+2HO and 3PbO PbO,+ PO, NO,+2HO &c., may perhaps be referred to this type. If we possessed some method of measuring the force with which salts are held in solution, we should be able to discover the law of its variation in the same class of salts according as one base was substituted for another, and for the same salt according as the temperature varied. The force with which a salt may be held by the solvent does not seem to bear much relation to its solubility. Charcoal removes salts of equal solubility from solutions in different proportions. It may, however, be justly objected to this, that the result is not due to a difference between the forces with which the salt and water are held together, but rather to the greater power of adhesion which the charcoal possesses for certain salts. I have begun a series of compara- tive experiments on the relative amount of different salts which pure charcoal and spongy platinum retain when solutions of various degrees of concentra- tion are passed through them, the results of which will, I hope, throw some light on this subject. The adoption of the hypothesis that crystalline salts are the result of double decomposition, appears to involve another consequence of great im- portance in the present inquiry, namely, that double salts do not exist as such in solution. In the case of double salts formed by the substitution of constitutional water, it is by no means necessary, as I have shown above, that the constituent salts of the double salt should be considered as existing un- combined in the solution, but simply in a different state of molecular arrange- ment. Favre and Silbermann were of opinion, however, that they did not exist in combination, and were only formed at the moment of their crystalli- zation. Graham, from his experiments on diffusion, has likewise suggested the possibility of the constituents of a double salt being dissolved together in water without being chemically combined. The latter considered that diffu- sion was capable of producing chemical decomposition ; for instance, that of bi- sulphate of potash, alum, and sulphate of potash in lime-water. This opinion harmonizes with the hypothesis of Favre and Silbermann ; and if understood in the modified form above suggested, namely, that the double salt, such as we know it in its crystallized state, does not exist in the solution, but that the constituent salts are nevertheless not free in every case, would be per- fectly accordant with it. Many isomorphous salts combine together in almost every proportion, such for example as the chromates and sulphates. H. Rose has analysed a compound of nitrate of silver and nitrate of soda to which he assigns the formula AgO, NO,+10NaO, NO,. If we adopt the hypothesis that crystallized salts are compounds of several molecules of the simple salt, we may consider the salt in question as x (NaO, NO,), in which one or more molecules of nitrate of silver replace a corresponding number of nitrate of soda. In accordance with that hypothesis, such a salt could not 300 REPORT—1859, exist in solution, and we find that many of them are undoubtedly decom- posed when dissolved in water. The simple double salts formed by non-iso- morphous salts, such as those formed by the magnesian sulphates, the alums, &c., are compounds of a higher degree, and are held together with much more force, and in most cases are not decomposed by water at common temperatures. If the constituent salts of alum existed free in solution, it would be difficult to account for certain phenomena to which Chevreul first drew attention. If cotton be immersed in a solution of alum of a given strength, it will absorb some of it, but it will be found that the solution absorbed docs not contain as much alum as the original one, that is, the cloth absorbs the water molecules more readily than the saline ones. Unless porous bodies, such as vegetable fibre, exert exactly the same adhesive power for sulphate of potash as they do for sulphate of alumina, which does not seem probable, the mere passage of a solution of alum through cotton, supposing the two sulphates not to exist in a state of combi- nation in solution, would be sufficient to alter their relative proportions. The mere fact of vegetable fibre exerting unequal attraction for the consti- tuent salts of double salts in solution, which in some cases at least it appears to do, would not, however, of itself constitute a proof that double salts did not exist, as such, in solution. It is very probable that the force binding the constituent salts of a double salt, and which is different for each one, is greatly diminished when the salt is dissolved in water; and that under those circumstances, the superior attraction of vegetable fibre, or porous bodies for one constituent salt, may be sufficient to overcome the chemical force by which the double salt is formed. The full investigation of this very import- ant problem forms part of the series of experiments to be made on the action of charcoal, spongy platinum, and other porous bodies on saline solutions, already ailuded to. The preceding discussion on the condition of double salts in solution, clearly shows that we could not determine their solubility without taking into consideration the whole subject of the constitution of salts, the action of salts in solution upon one another, and the nature of solution. It fully justifies me therefore in viewing the subject which I proposed to investigate from the general point of view which I have done, instead of confining my- self to the construction of a few imperfect tables, and which, though they may, if carefully constructed, be practically useful, could give very little aid towards the advancement of chemical theory. If I have succeeded in the preceding pages in sketching so much of the general outlines of the subject of investigation as to convey an adequate idea of its character and scope, the classification which I have made of the several groups into whick the experiments to be made may be divided for greater convenience of study, and the general character of the experimental processes which I have employed, or propose to employ, will be at once understood. A very brief account then of these two matters will complete what I proposed to do in this preliminary report: and first of the classifi- cation. In an investigation involving so great a variety. of detail, and in which ' so many physical phenomena must necessarily be employed as tests of molecular changes, the experiments require to be so classified that the results obtained in connexion with each class of phenomena shall be com- parable, and that the results of one series of experiments shall throw light upon, and assist in carrying out the next, and lastly, that all shall converge to the main problem. The following scheme of experiments, if made upon an extensive scale sufficient to enable us to eliminate errors and anomalies, ON THE SOLUBILITY OF SALTS. 301 would afford us data to lay the foundation of a rational theory. The scheme embraces so much that I am in no danger of being suspected of the design of executing it all. It may be asked, why then sketch a plan which I could not execute? Because, in the first place, as I have already endeavoured to show, the determination of the true law of solubility of even a single salt, involves the whole of the questions which this scheme of experiments is pro- posed to investigate ; and consequently, in any attempt to determine such a law, the whole of them must of necessity be more or less studied. And in the second place, because I believe that in the investigation of details we are apt to forget the generalities to which they are subordinate, an error which is avoided by following a plan in which every result, however trivial, finds its place and immediate use. Science will gain more in this way than by desultory experiments, which, in consequence of their isolation, remain for a long time barren. 1. I have found that many hydrated silicates, sulphate of lime, &c., when immersed in water and exposed to a high temperature, lost part or all their hydrated water. This suggests an important question—Do all hydrated salts lose their water, if heated in that liquid to a very high temperature? And if so, do any of them offer a similar phenomenon to that which certain hydrated salts present when heated in the air, namely, of losing their water in successive portions as the temperature rises? Thus, for example, the salt 2KO, PO,+3HO loses one equivalent of HO at 100°, a second at 180°, and the third only perfectly at a red heat. The question suggested here applies to all salts that contain constitutional water. In such a salt as that above mentioned, is each molecule held by a different amount of force? and does it therefore enter with a different atomic volume into the compound? or is each equivalent held with the same force at the commencement of the operation, the change of constitution being the result of a modification of equilibrium produced by the heat? It appears to me that the study of the action of saturated solutions of salts upon the crystals of the hydrated salt at different temperatures would throw much light upon these questions, as well as upon the very important one of whether hydrated salts retain their water in solu- tion. I hope very shortly to be in a position to report upon this branch of the subject. 2. The second series of experiments is to be devoted to the investigation of the influence which different proportions of an acid exert at different tem- peratures upon the maximum solubility of the different salts which it forms with such bases as do not yield any known higher acid salts than those ex- perimented upon. Some singular anomalies are presented by salts in this respect, as, for example, the well-known ones, KO, NO, being more soluble in dilute nitric acid than in pure water, while BaO, NO, is precipitated from a strong solution by nitric acid. A similar series must be made for the influ- ence of bases upon the solubility of such salts as they form, with those acids with which they do not yield recognizable basic salts. 3. The next series will be devoted to the study of the influence which different proportions of soluble acids exert, at different temperatures, upon the maximum solubility of soluble salts containing a different acid soluble in water, and with the base of which the intervening acid does not form an in- soluble compound. In the cases contemplated here, there would be, accord- ing to Berthollet, decomposition in proportion to the mass of the intervening, acid. We have direct evidence of this when HCI acts upon a solution of CuO, NO,; but hitherto we have had no means of proving it where the solu- tions were colourless. Besides the obvious importance of such experiments in connexion with the subject of affinity generally, I think they will afford 302 REPORT—1859. the means of throwing some light upon the question, whether such a thing as single elective affinity does take place, or whether all combinations and de- compositions are not cases of double decomposition? If the actionof HCl upon CuO, NO,, or of NO, HO upon CuCl, be a case of double decomposition, water must take part in it, and, like all other bodies, must act in proportion to its mass. The proportion of water must consequently be taken into ac- count, as well as those of salt and acid; and if any means can be devised for ascertaining the amount of decomposition, experiments should be made with solutions of different strengths as well as with the saturated solutions. 4. The fourth series may be considered as a continuation of the last, and will consist of experiments upon the influence which different proportions of the soluble bases, KO, NaO, BaO, SrO, CaO, and NH,O, exert at different temperatures upon the solubility of one another's salts. Here too we may assume double decomposition ; in fact, all these bodies are present in solu- tion apparently as hydrated oxides. Ammonia exerts a singular influence upon the solubility of some salts, such as sulphate of potash, which it preci- pitates from a strong solution. It would be interesting to include in the inquiry the action of the compound ammonias, as they will no doubt be found, while resembling ammonia in many respects, as regards their chemical func- tion, to differ in respect to their influence on solubility. The action of the compound ammonias is interesting from another point of view likewise. Urea, as is well known, if added to a solution of common salt, causes it to crystallize in octahedrons. If we look upon urea as a diamide in which part of the hydrogen is substituted by a polyatomic radical, all other substances belonging to the same type may perhaps produce alike change. Difference of form in the same substance is generally, perhaps always, accompanied by a change of solubility ; such a difference may perhaps exist between the two forms of common salt; so that this series of experiments is of considerable importance. The crystallization of common salt from urine in the form of octahedrons appears to have been known to Romé de Lisle. Foureroy and Vauquelin showed * that this change of form was due to urea. Beyond this very important fact, little, if anything, was known of the influence of foreign substances upon the crystalline form of bodies, until the publication of Le- blane’s memoir in 1788+. He made many valuable and interesting ob- servations. But it is to Beudant }, who brought together everything that was previously known on the subject, confirmed and very greatly extended the observations, that the subject is indebted for the interest and importance which it now has, and which has led to many new investigations. Among those who have more recently studied the subject, may be mentioned Nicklés, Senarmont, and Pasteur. The latter gives a very remarkable instance of this kind of influence§. The acid malate of ammonia crystallizes in rectangular tables of the rhombic system, sometimes having two parallel edges bevelled ; the faces 2 are never observed whenever the salt is crystallized from a pure solution. But if a part be heated until it has begun to be decomposed, and then dissolved in water, and the impure solution allowed to cool, the crystals formed in it have hemihedral faces, which disappear when the crystals are again made to grow in a pure solution. The action of nitric acid upon the nitrates of potash and of baryta, and of ammonia upon a solution of sulphate of potash, may be due to a change of this kind. The subject has never been * Ann. de Chim. et de Phys. vol. xxxii. p. 80 (1799). t+ Journal de Physique, xxxiii. } Ann. des Mines, iii. (1819), and Traité de Minéralogie. § Ann. de Chim. et de Phys. 3™° Série, vol. xlix. p. 5. ON THE SOLUBILITY OF SALTS. 303 systematically studied. The scheme of experiments proposed in the next section upon the influence which salts exert upon one another’s solubility in virtue of their comparative morphology, may, however, afford an opportunity of doing something in this direction. 5. The fifth series of experiments will be devoted to the influence which salts exert upon each other's solubility. Strictly speaking, we may consider acids and bases as salts; but it will be better for the special purposes of this investigation to consider them separately. In studying the influence which substances exert upon one another in solution, we must take into account, not merely their chemical composition, but their crystalline form likewise. Even though we may admit that a hydrated salt, when dissolved in water, parts with its hydrated water, and that therefore the body which is in solution belongs to a different crystallographic system from the hydrated salt, there can be no doubt that some peculiar molecular condition must exist in the solution just before the separation cf the hydrated salt, under the influence of which the molecules of anhydrous salt combine with a definite amount of water. We must also bear in mind, that in a great many instances certain molecular properties intimately connected with crystalline form, such as the power of circularly polarizing light, &c., are inherent in the molecules, and therefore independent of their physical state. I have thought it desirable, therefore, to classify the salts which I propose to experiment upon in this series according to the following crystallographic scheme :— A. Isomeromorphous bodies, that is salts which crystallize in forms of the regular system, and possess similar formule. They may be subdivided into,— a, isatomes, or those which have equal atomic volumes, made up of the same number of integrant molecules; and 6, polyatomes, or those which possess equal atomic volumes, but made up of an unequal number of integrant mole- cules—isomorphism being supposed to be in general due to equal or approxi- mate specific volume. B. Icono-ideomorphous substances, a name which Laurent first employed to designate such substances as the laevo- and dextro-tartaric acids, which are the images of one another viewed in a mirror, as Pasteur by his admirable researches has shown. Under this category will be included all hemihedral forms in opposite directions. C. Homcomorphous salts.—True isomorphism can only exist between bodies crystallizing in the regular system, the term homceormorphism has accordingly been proposed to designate the isomorphism of the other systems, in which there is not perfect equality of angles or parameters. Laurent believed that two bodies ought to be considered as isomorphous, even though belonging to different systems, if their angles and parameters are nearly equal. He argued that if a rhombohedron of 103° ean be considered to be isomorphous with one of 104°, 105°, or even of 107°, there is no valid reason why one of 89° 30/, or of 90° 30! should not be isomorphous with a rhombo- hedron of 90°, that is with the cube which is the limiting form between the acute and obtuse rhombohedrons. It is in this sense I propose to use the term. I likewise propose to restrict the term to such bodies as have similar formule, and, like the isomeromorphous bodies, will divide them into ¢sa- tomes and polyatomes. D. Many substances can have exactly the same shape, or nearly the same shape, though they may wholly differ in chemical constitution. Such bodies cannot be considered as isomorphous or homceormorphous in the sense above contemplated. As identity of shape, however different the composition may be, must imply a certain amount of similarity in the conditions of equilibrium of their molecules, it is obviously of importance, in an investigation like the 304 REPORT—1859. present, to examine the action which such bodies exert upon each other’s solubility. This kind of isomorphism and homceormorphism may be described by the term heteromeric, first employed by Hermann. Heteromeric homeeo- morphism is in part what Laurent termed paramorphism. E. Dimorphic and trimorphic substances may be isomorphic with two or three different series of bodies in as many different systems. This isomor- phism may be ésomeric ov heteromeric. ‘The influence which the bodies of each series would exert upon the solubility of a dimorphic salt would be ex~ tremely interesting, and especially as regards the comparative influence of the bodies isomorphic with the most stable form, and those isomorphic with the least stable at different temperatures. F. The last category of forms includes the hemimorphous bodies in the sense in which Laurent used that term; that is substances which resemble each other in composition, but which are only partly similar in form—which have one or two angles alike, but all the others very different. The application of this scheme of comparative morphology to the subject of this investigation is so obvious that I need not dwell upon it now. By submitting a salt in solution at different temperatures to the action of suc- cessive quantities of a number of salts, beginning with those which exhibit perfect identity of form, equality of volume, and similarity of composition, and proceeding downwards, as indicated in the preceding scheme, until re- mote indications of resemblance are alone perceptible, I hope to be able to ascertain the general character of the influence which form exerts upon solu- bility. To complete the series, it would perhaps be necessary also to study the action of salts which have no resemblance of any definite character. The modification in solubility which a salt undergoes on adding a given quantity of another salt, is not, however, due to form alone; the chemical nature of the molecules engaged has perhaps a larger share in the phenomenon. The results of such a series of experiments as I have just planned would not therefore enable us to determine the influence of form, unless we could eliminate the effect due to chemical action, properly so called. This could only be done by making a series of experiments on the influence of chemi- cal composition, according to a scheme of classification analogous to that sketched out for form. This will consist essentially of the following :—a, influence of a number of the soluble salts which the acid of the salt investi- gated forms with different bases; 5, influence of the soluble salts formed by the base of the salt under investigation, with different acids; ¢, in- fluence which the salts of sesquioxides exert upon the solubility of the salts of the protoxide of the same metal, and upon the protoxide of other metals, where they do not form recognized double salts; d, influence which salts of polybasice acids, with one, two, &c. of strong base exert upon the solu- bility of different salts ; e, comparative influence of tribasic phosphate of soda, containing two of sodaand one of water, and bibasic phosphate of soda with two of soda, &e. I have perhaps discussed the classification which I propose to follow im my experiments sufficiently to make the character and scope of the investi- gation evident, and it now only remains for me to say a few words of the methods which I propose to employ in order to determine, if possible, the nature of the changes which take place on mixing saline solutions, and in heating a single solution, or a mixture, to a high temperature. In the following observations upon the physical phenomena which may be taken advantage of 1o determine the molecular changes taking place without precipitation when solutions are mingled, I propose to mention those only which as yet I have tried with some hopes of usefulness. ‘There ON THE SOLUBILITY OF SALTS. 305 are many others which I may hereafter try to make use of, and some of which have been employed for analogous purposes by others; such, for example, as the influence which solutions exert upon the spectrum, as shown by the ingenious experiments of Dr. Gladstone, who I hope may be induced to take up the whole question of the optical relations of saline solutions. Relative Compressibility of Saline Solutions—Among the most important physical phenomena the more complete study of which promises to throw light upon the nature of solution and the action of salts in solution upon each other, may be mentioned their compressibility. As all the experiments upon the solubility of salts at high temperatures must be conducted under high press- ure, 1 must necessarily begin by investigating the action of pressure alone upon saline solutions in the cold. With the exception of the experiments of Grassi, made with Regnault’s piezometer, we have no records of any in which saline solutions were examined. Grassi’s, too, are mere isolated examples, not sufficient to enable a law to be established ; the pressures, too, were very limited. The experiments of W. Thomson and Bunsen show that the point of solidification of bodies is lowered by pressure; hence we may expect that solutions of salts, if subject to pressure, would crystallize. There is a re- markable experiment of Perkins which bears out this supposition ; he ex- posed glacial acetic acid with jth water to a pressure of 1100 atmospheres, and found that tths of it had crystallized in a few minutes. In some trials which I have commenced, and in which I have used Epsom salts, nitrate of potash and common salt, high pressure alone appeared to produce erystal- lization. I obtained the pressure by the method employed by Degen* to ascertain whether oxygen and hydrogen combined with one another under great pressure. This method consists in decomposing water in a closed tube, by means of a voltaic current. I employed a U-tube, in one leg of which I placed the solution of the salt, and in the other the water to be decomposed. The decomposition was effected by means of two platinum wires soldered into the glass. Degen introduced a manometer-tube into his apparatus, by which he was able to register the pressure. In my first experiments I did not think this necessary, as they were only tentative. As it will be necessary to make a series of pressure experiments upon every salt the solubility of which I may seek to determine at high temperatures, in order that I may be able to determine what is due to pressure and what to temperature in the phenomena of solution at high temperatures, I must use a manometer in all future experiments. I am in hopes that a series of experiments made with Regnault’s piezometer upon the comparative compressibility of concentrated solutions of single salts, and of mixtures of salts according to the schemes of classification, according to form and chemicai composition above suggested, ‘may give results which can serve to indicate molecular changes not other- wise recognizable. It is also probable that many new hydrates may be pro- duced under the influence of great pressure; and that the character of the precipitates, the form, specific gravity, and other physical properties of salts crystallized under the joint influence of pressure, and the presence of other substances in solution, may present interesting modifications. The experiments of Grassi having shown that the compressibility of distilled water free of air decreases as the temperature rises, while the com- pressibility of all the other Auids experimented upon increases with the tempe- rature, the action of pressure upon the solutions of salts in water must be different from that which it exerts upon similar solutions in alcohol, ether, &e. I will not discuss this subject further here, as I hope very soon to be * Poggendorff’s Annalen, vol. xxxviii. p. 454. ‘ 1859. x 306 J REPORT—1859. able to bring forward the results of some experiments on this very interesting branch of the subject. Capillary Ascension and Diffusion of Saline Solutions.—The experiments of Valson, Poiseuille, and Willibald Schmidt, indicate that the capillary height of fluids and the rapidity of their flow through capillary tubes is not alto- gether dependent upon their density, but is also influenced by the nature of the substances in solution. Valson * has examined the influence which the addition of one fluid would have upon the capillary height of another. He finds that this would be different according as the intervening fluid acted chemically or not upon the other; in the latter case only did the capillary height appear as a linear function of the increment of volume, while both those magnitudes may be expressed by an exponential curve with asymptotes when chemical action takes place. He has deduced the following results from experiments made with sulphuric acid (HO, SO,), concentrated acetic acid, and alcohol, by the successive addition of increments of water to them: —1, that a change of capillary height takes place regularly as each success- ive increment of water is added; 2, the action of the successive increments upon the capillary height diminishes; 3, a modification of molecular activity exerts a greater influence on the capillary height than an alteration of specific gravity of the fluid mass; 4, the mixture of the bodies above named, although capable of being made in every proportion, may nevertheless be considered to belong to the category of chemical combination. Valson found that the addition of about >,4,,; of alcohol to water produced an alteration of 0:2 millim. in a capillary column of 41°48 millims., which was very well determinable by the cathetometer. The experiments of Poiseuille to which I refer, are those upon the flow of liquids through capillary tubes?. From those made with water and alcohol, he infers that the velocity of the flow is directly proportional to the pressure, and inversely to the length of the tube, provided that this length does not fall below a certain limit which increases and diminishes with the diameter ; for shorter tubes he found that the velocity increases more rapidly than the pressure. He found further that, all other conditions being the same, the quantity discharged is proportional to the fourth power of the diameter of thetube. The addition of substances soluble in water modified, however, the velocity of flow ; iodide, bromide, and cyanide of potassium, nitrate of potash, nitrate of ammonia, chlorides of ammonium and calcium, and acetate of ammonia accelerated it, while bases retarded it. Among the acids only two appear to have accelerated it,—hydrocyanic and hydrosulphuric acids. He only obtained negative results from his further researches to determine how far the alteration, produced by the addition of various substances, in the density, capillary height, liquidity, boiling-point, contraction on mixture, solubility and efflorescence of the substances added, &ce., stood in any simple relation to the modification in the rate of flow. The experiments of Schmidtt on the influence of temperature on the rapidity of filtration, confirm in the main Poiseuille’s results just given. | I propose to use both the capillary height as determined by the catheto- meter, and the flow of the solutions through capillary tubes, as tests of the molecular changes which take place in solutions of a single salt at different temperatures, and with mixtures of salts according to the schemes laid down above. The instrument which I am constructing for the experiments on the flow of the solutions consists of a modification of Vierordt’s endosmometer, by which I can use tubular diaphragms of various lengths and diameters of tubes, * Compt. Rend. vol. xlv. p. 101. + Ann. de Chim. et de Phys. vol. xxi. p. 76. + Poggendorft’s Annalen, vol. xcix. p. 353. - ON THE SOLUBILITY OF SALTS. 307 and apply a constant pressure during the whole time of the experiment. I propose, in addition to diaphragms composed of capillary glass tubes cemented together, to use also a series of platinum plates of various thicknesses, and pierced with holes of successively increasing diameters. By means of this instrument I shall be able not only to make experiments on the flow of liquids from a full vessel through capillary tubes into a space filled only with air, but likewise on the phenomenon of diffusion through such tubes—a kind of osmosis corresponding to what Fick calls pore diffusion. Phenomena connected with Density—The phenomena belonging to this category which may serve as tests of molecular changes in saline solutions, are,—l, density at various temperatures of solutions saturated at 0° and 100° and other intermediate points; 2, amount of condensation which takes place in saturated solutions when effected at different temperatures ; 3, condensation which takes place on diluting saturated solutions with successive equivalent quantities of water; 4, density of supersaturated solutions at various tempera- tures; 5, point of maximum density of solutions ; 6, influence of pressure upon the point of maximum density, and on the amount of condensation which results from dilution. The densities of a great number of saline solu- tions have recently been determined with great care by Kremers and Gerlach, and Léwel. These furnish valuable data both for scientific and practical purposes, and will be of the greatest assistance to me. In subjects of this kind, both on account of their extent and character, every observer has necessarily his own point of view, and makes use of different means to attain the same result. Thus for my special object I consider it better to confine my attention at first to saturated solutions, than to experiment upon solutions of different degrees of concentration. With regard to the point of maximum density, I shall only have to endeavour to continue what Despretz has so admirably begun. Thermology of Saline Solutions.—I shall do little more than indicate on this occasion the phenomena connected with heat, which may be studied as tests of molecular changes, They are,—l, expansion of saturated saline solutions, already included under the head of density; 2, contraction of saturated solutions before they yield any crystals; 3, changes of volume which accompany crystallization ; 4, point of congelation of saturated saline solutions; 5, boiling-point of saturated solutions; 6, latent solution and dilution heat of single salts, and of mixtures made according to the schemes laid down above; 7, specific heat of such solutions; 8, tension of vapours from saline solutions, Nothing need be said here on the subject of expan- sion of saline solutions, as the value of determinations of the rate of ex- pansion can only be judged of as tests of molecular changes when we are in possession of data upon the other physical properties of solutions. The contraction which saline solutions undergo in cooling before crystals separate is of great importance, and in many cases will be found not to correspond to the expansion when heated through the same number of degrees. The changes of volume which accompany crystallization, and the point of con- gelation of saline solutions, are intimately connected with the subject of their latent solution and dilution heat and their specific heat. The study of these phenomena includes,—1, the determination of the specific heat of the solid and fused anhydrous salt itself, and of the hydrates which it forms; 2, simi- lar determinations for mixtures of salts according to the schemes laid down above, whenever such mixtures can be fused together; 3, and lastly, of determinations of the latent fusion heat of simple salts and mixtures of salts. As regards the boiling- points of saline solutions, I propose to divide this part of the investigation into two parts; first, to determine the maximum effect x2 308 REPORT—1859. which each salt experimented upon can produce in raising the boiling-point ; secondly, to determine, as Legrand did for a great number of salts, how much of each salt would be required to raise the temperature of boiling by one degree Cent. successively from 100° to the maximum which the particular salt can raise it to; aud thirdly, the effect of mixture in the laws established for the pure salt. The study of the tension of vapours from saline solutions promises to be a very useful test of molecular changes. Regnault believes that the vapour from boiling saline solutions has the same temperature as the solution, and that the study of the tension of the vapours of such solutions might determine the im- portant problem, whether salts were still joined to their crystalline water when in solution, and may in this way prove as useful a test as polarized light ; and also whether double salts exist in solution, or are only formed at the moment of crystallization. Rudberg concluded from his experiments that the temperature of vapour arising from saline solutions was independent of the temperature of the solution. Von Babo has found* that the vapour from a boiling saline solution has less tension than steam of a corresponding tem- perature. Pliicker has also foundt that the vapour tension of saline solutions is less than that of pure water, and that the difference of tension may answer as a relative measure of the active molecular force between the salt and water, and of the law of its increase with the increasing quautity of salt. He states that the diminution of tension of the vapour is so directly propor- tional to the increase of salt, that the determination of this tension at 100° Cent. will give the per-centage of salt to solution, at least as well as the finest areometer. Willner} has also found that the differences of tension are directly as the quantities of salts dissolved. The differences of tension are repre- sented by a differently expressed function of the temperature for each salt and mixture of salts. He also finds that no relationship can be established between the differences of tension and any of the other properties of the salts, especially the solubility ; which fully bears out a conclusion which I came to above upon different grounds, that the force with which a salt may be held by the solvent, does not seem to bear much relation to its solubility. He also states that salts which cannot act chemically upon one another, modify each other’s attraction for the water, when they occur together in solution. As it is doubtful whether any such salts exist, this would mean that all salts modify each other’s affinity for water, when their solutions are mixed. Wiillner also considers the differences of tension to be a measure of the actual attractive force between the water and salt. It appears to me that the difference of tension can serve as a measure of the amount of decomposition which takes place on mixing two soluble salts which do not give a precipitate, and also of the influence of mass and of form iu such decompositions at different temperatures. I accordingly propose to use them for that purpose, as well as also in conjunction with the experiments which I am making on the removal of salts from solutions by porous substances not acting chemically upon them, as a measure of the force by which salts are held in solution. Pliicker has also observed some very remarkable affinity relations which admit of being numerically determined when to a mixture of two fluids a third is added, or when a salt is dissolved in the mixture—which is indeed the case upon which he lays most stress, and the tension of the vapour de- termined, and from this the composition calculated. Thus, for example, * Ann. der Chem. und Pharm. vol. Ixvii. p. 356. +t Poggendorff’s Annalen, vol. xcii. p. 193. ¢ Ibid. vol. ciii, 529; and vol. ev. p. 85. ON THE SOLUBILITY OF SALTS. 309 water added to a mixture of alcohol and ether increased the tension of the mixed vapours and lowered the boiling-point of the mixture. In the same mapner common salt considerably increases the tension of the vapour which rises into a closed space from a mixture of alcohol and water, and diminishes the boiling-point. Pliicker did not experimentally determine the relative proportions of each vapour before and after the addition of the salt. It would not be easy to do so; but if it could be accurately done, it would be of great importance, for it seems to me to be necessary in order to control the calculated determinations, and help to give a correct explanation of the phenomenon. From some experiments made with mixtures of other sub- stances, I have found that the relative proportion of each liquid which distils over from a mixture of two or more fluids, before and after the addition of a salt, is very different, but I have not yet determined the influence of temperature, relative proportions of the fluids forming the mixture, and of the mass of the salt, upon the proportions. The action of chloride of calcium upon a mixture of methylic alcohol, acetone, and a number of other liquids, the aleohol being in largest quantity, throws much light upon the phenomena observed by Pliicker. The mixture alluded to dissolves fused chloride of calcium with great facility; when a large quantity has been added, the fluid suddenly splits into two layers, the heavier of which contains the whole of the chloride of calcium, the lighter none. All the fluids of low boiling-points happened to separate from the chloride of calcium in the cases which I happened to observe. On heating the chloride of calcium solution in a retort, a large portion of the liquid distilled over; on adding water to the residue, and ap- plying heat, another separation took place of some oily compounds, which distilled over along with water. If the mixture was distilled in the first instance before sufficient chloride of calcium had been added to cause the separation of the fluids, we should have an excellent example of the case de- scribed by Pliicker. The molecular union of the atoms Z O, and CH. O, may be assumed to have been disturbed by the atom of NaCl, which had a stronger affinity for the water than the latter had for the alcohol ; the alcohol was accordingly set free and lowered the boiling-point. The separation of the liquid into two parts does not always take place so evidently as in the ease which I have above described, but it is probable the effect is essen- tially the same. If this explanation be true, certain salts ought to produce a diminution of tension, and the boiling-point ought to rise; thus, if we add a large quantity of salts which are more soluble in ether than in alcohol to a mixture of those fluids, the boilizg-point ought to rise, unless the adhesion of the salt and ether be so much diminished by the heat, that the ether should separate again in part and distil over. I had an opportunity of observing an example of this kind in the case of some very volatile, oleaginous bodies, some of which combined with CaCl. Generally speaking, however, the heat required to vaporize the denser oils was sufficient to decompose the molecular combination with the CaCl, although it was sometimes possible to produce the splitting into two fluids. The whole subject is evidently one well worth further investigation, as I have no doubt that very great light would thereby be thrown upon the nature of solution. It also affords a measure of the comparative forces by which different salts are held by water and other solvents, and which I propose to make full use of for that purpose. The diathermancy of solutions, which has been made the subject of inves- tigation by Frantz, may likewise be made use of hereafter, as also the optical properties, such as their refractive and dispersive powers, &c. Kremers has 310 REPORT—1859. already made many experiments upon the former. As I have not attempted anything in this direction as yet, I shall not dwell upon these subjects; the more so, as I believe I have fulfilled the object with which this preliminary report was written; namely, to give an idea of the character of the work I am engaged in, and the manner in which I propose to execute it. In con- clusion, I shall only say a few words on one other feature of my plan of re- search which I hold to be of paramount importance. Hitherto I have only alluded to the subject of atomic volume, as a secondary element of morpho- logical classification (isatomes and polyatomes). This has not arisen, how- ever, from want of appreciation of the great benefits which chemical theory has derived from the introduction of the doctrine of atomic volume into science, and especially from the labours of Kopp and others in connexion therewith. The opinions put forward by Avogadro, Hunt, and others, whatever may be their intrinsic merit, show us that there exists as yet much room for diversity of opinion. On this account I will not, in the first instance, introduce the element of volume at all into the discussion of my numerical results. Many experimentalists have used in their experiments on points connected with molecular physics, quantities of the bodies operated upon which bear no relation to the proportional weights, according to which all chemical com- bination takes place. The remarkable laws of combination are too univer- sally true to allow us to doubt that, although there maybe a difference between chemical and physical molecules, there must be some simple mul- tiple relations between them. The remarkable relation established by Du- long between the proportional weights (equivalents) of bodies and their specific heat, is a striking confirmation of this opinion. In all the experi- ments which I propose to make, I will, as I have likewise heretofore done, always use the bodies operated upon in equivalent proportions. If we experi- ment on the physical properties of a single homogeneous substance, it makes no matter what quantities are employed, because by a simple calculation we can reduce our numerical results to equivalent quantities ; it is quite other- wise, however, when we operate upon mixtures, for here any excess over the equivalent quantity influences the results, especially if we assume solution to be a chemical process. In this way I hope to be able to avoid all per- plexing anomalies, arising from the presence of an excess of one constituent in a solution, which could interfere with the ready perception of any law governing the phenomena. Provisional Report on the Progress in the Solution of certain Special Problems in Dynamics. By A. Cayuery, F.R.S. Tue author stated the reasons which delayed the furnishing of the full Re- port, which he hoped to have ready for the next Meeting of the Associa- tion. NOTICES AND ABSTRACTS Or MISCELLANEOUS COMMUNICATIONS TO THE SECTIONS. buf 4 ag ay ee oe « } ke tee Es eet Ws Nex t ACT aT OT RE OTE AG Ls NOTICES AND ABSTRACTS OF MISCELLANEOUS COMMUNICATIONS TO THE SECTIONS. MATHEMATICS AND PHYSICS. MATHEMATICS. Introductory Remarks by the President, The Ear or Rosse. Ir has, I believe, been usual, at least recently, in opening the proceedings, to give, as far as may be practicable, a general outline of the business to be brought before the Section, and some kind of notice of the order in which it is likely to be taken. As, however, many papers are often sent in after the meeting of the’ Section, and as frequently circumstances arise rendering it necessary to alter the order of proceeding, any notice that can be given must be very imperfect; the daily notices, however, will in some degree supply the deficiency. It has also been usual, I believe, and it is obviously convenient, in some degree to define the general character of the business to be transacted, so that new Members may be enabled better to decide whether to attend this Section or some other. I have made inquiry, and find that already there have been received papers on pure mathematics, applied mathematics, magnetism, light, electricity, and meteorology, besides papers on the construction of philoso- phical instruments. From the titles of the papers, some idea may be formed of the general character of the business to be transacted; still there are many subjects, in fact several branches of science, which are as yet unrepresented in the papers. First as to the papers on pure mathematics. I need perhaps hardly say that essays on so abstruse a subject cannot be of very much interest except to mathematicians ; and even mathematicians, unless the papers happen to relate to the particular branches of mathematics with which they are most conversant, may perhaps be sometimes unable to do more than catch the general scope and leading principles of the paper; still without mathematical knowledge many may often, in the results announced, and indeed in the remarks casually elicited, obtain interesting glimpses into the nature of mathematical processes, and some idea of the progress making in that direction. In applied mathematics there is much more of general interest, and the results are often perfectly intelligible without a special education. I recollect at the Meet- ing of the British Association at Oxford, the general results of a very abstruse in- vestigation in applied mathematics in physical astronomy, were so brought forward as to rivet the attention of the whole Section. It was an account given in general terms by M. Le Verrier of his researches for the identification of a comet. The discoveries in electricity, magnetism, heat, and light cannot fail to be of great general interest. To the human mind nothing is so fascinating as progress. It is not that which we have long had we most value, but that which we have recently acquired : we especially prize new acquisitions, while we enjoy almost unconsciously gifts of far greater value we have long been in possession of. This is our nature ; thus we are constituted ; it certainly is not surprising therefore that we should have 1859. 1 Z REPORT—1859. a peculiar relish for new discoveries. The interest of a discovery is not usually con- fined to the discoverer, unless he is very churlish, or even to those who are endea- vouring to discover ; but it often extends to the whole civilized world. The interest is, however, not lasting ; for a time we are dazzled by the brilliancy of the discovery ; gradually, however, the impression becomes fainter, and at last it is lost entirely in the splendour of some fresh discovery, which carries with it the charm of novelty. When we reflect upon this, we cannot but perceive how very different the state of the world would have been had mankind from the beginning been in possession of all the knowledge we now have, and there had been no progress ever since. We ask, why have all these wonders been placed before us—hidden, veiled—only to be brought to light by the vigorous use of our faculties? How wonderful from its origin has been the progress of geometrical science! Beginning perhaps 3000 years ago almost from nothing, one simple relation of magnitude suggesting another; the relations beco- ming gradually more complicated, more interesting, more important, till in our day it expands into a science which enables us to weigh the planets ; more wonderful still, to calculate long beforehand the course they will take acted upon by forces continually varying in direction and magnitude. When we ask ourselves such questions as these considerations suggest, and thoughtfully work out the answers as far as pos- sible in their full depth of detail, we become in some degree conscious of the immense moral benefits which the human race has derived, and is deriving, from the gradual progress of knowledge. ‘The discoveries, however, in physical science are often im- mediately applicable to practice, giving man new powers, enabling him better to supply his many wants. We therefore, who are all, in some degree at least, utilita- rians, on that account very naturally regard them with deep interest. Iam sure the mere mention of the subject has already suggested to you many of the extraordinary discoveries of latter times ; for instance, the production of force almost without limit by heat, and its application to locomotion by sea and land,—the transmission of thought, not slowly by letter, not to short distances by sound, but instantaneously to immense distances by electricity ; and when we look around us and see how man has appropriated to his use the properties of light and heat, the powers of wind and water, the materials which have been placed before him in endless variety on the surface of the globe which he inhabits,—that he has effected all this by knowledge accumulated by what we call Science,—it is surely not surprising that we should look upon new discoveries with surpassing interest. The mere utilitarian, however, has been often reminded that discoveries the most important, the most fruitful in prac- tical results, have frequently in the beginning been apparently the most barren, and | therefore that the discoveries in abstract science are not without interest even for him. I confess, however, that the gradual development of scientific discovery,—in fact, in other words, the steady flow of knowledge into the world—which like a stream becoming broader and deeper as it proceeds points to its own source, to its own origin, which is the origin of man,—TI confess that this arrangement appears to me to serve far nobler purposes than merely to minister to the corporeal wants of man, as they increase, cr are supposed to increase, with the progress of civilization. What those purposes are, to some extent, I think we may clearly see, though to fathom the full depth of such an inquiry would be beyond our powers. Looking merely on the surface, we perceive that the continual springing up of new facts, new discoveries, in endless succession, the rewards of industry, must tend to make man industrious. It inspires him with hope, entices him to labour with his mind— the hardest of all labour; it quickens his faculties, it forces him to look behind and before, to the past and future, and it promotes in him a high moral training by the influence it exercises over his habits and thoughts. Many, no doubt, will feel anxious to see principles immediately applied to practice ; in common language, to see prin- ciples made useful: they will be highly gratified in the Mechanical Section. Here they may, perhaps, occasionally see the same thing ; but more frequently they will find that the results are but stepping-stones which prepare the way for further pro- gress. These few remarks, which I have made principally for the convenience of new Members, will, I think, be sufficient to give some little idea of the kind of busi- ness to be transacted here, and I will not allude to the actual practical results which have immediately followed from the labours of this Section. They have been detailed, and recently, especially by my friend on my right hand, Dr. Robinson ; TRANSACTIONS OF THE SECTIONS. $ and I will only further add, that I feel much gratified to find so large an attendance of eminent men of science here, ready to correct oversights and supply deficiencies. They, I am well aware, are far more competent to preside here than I can be ; but, with their assistance, the duty will be light; and as the Council, no doubt on good grounds, have made the present arrangement, | will, without hesitation or misgiving, at once proceed with the business, On the Probability of Uniformity in Statistical Tables. By R. CAMPBELL. The object of this paper is to find a test for ascertaining whether an observed degree of uniformity or the reverse in statistical returns is to be considered remarkable. Suppose the population to consist of m persons, which we will suppose nearly con- stant. Let @ be the number of years during which observations are taken, and sup- pose the whole number of phenomena of a certain class occurring to, or presented by, the individuals in the population to be ad. We will suppose the phenomena of a kind which are not likely to occur to the same person more than once in the same year, [Of this nature are most important facts, of which such Tables are formed. ] Now suppose we know nothing of the laws by which these facts occur, except that above given, namely, that the total number in a years is ab. Let us see what kind of uniformity (starting from that fact alone) we should expect the Tables to present. Let the people alive in a particular year be Aj, Ag...An. The probability then of the phenomenon being presented in that year by A; is : . The probability that n it will be presented by A, and not by A, will be 2 a n an— the probability of its being presented by A; only; the probability of its being pre- sented by one person only ; the probability of its being presented by two persons only, and soon. ‘These expressions will be very complicated. That for the probability of the phenomenon being presented by b persons only will be (n—1) (n—2) ... (n—D+1) ab—1 ab—2 ab—b+1 (1- a= a9 4G *9*on—1 an—2 an—b+1 an—b je 8 j—__ vb ( an—(b+1) ceeeee( reste Ny Now though these expressions are complicated, we get some very simple results. The above expression would be deducible from the expression for the probability of the phenomenon being presented by 6—1 persons only, by multiplying by a factor b(a—2 which reduces itself to 1+ Bor ). Hence we can find It would be deduced from the expression for the probability of b+1 persons pre- senting it by multiplying by a factor, which reduces to (a—1)n—(a—1)b+1 (gis a= SS 13 (n—b)(a—1)b Now these are always greater thanl. ‘This shows that the average number is the most probable one to occur in a particular year. The ratios of the probabilities of 6 occurring, to that of (b—1), (o—2), &c. are 6 to 6-1, m—b+1 ab—b+] b ep SST ae mc a eC b to b-2, (n—b+1) (M—b4+2) | ab—b+1 ab—b+2 b. @—1) an—ab—n—b an—ab—n—b+1’ 2h Roles (b) and so on, Sa ‘ F i: A . ; ‘ a 4 REPORT—1859. b to 6+1, b+1 an—ab—n—b-1 Pa ig aa Me are eee ee a, b to 64-2, (+1042) {an—ab—(n—b—1) }fan—ab—(n—b—2)} (8) (n—b)(n—b—1) (ab —b)(ab—b—1) : These results are capable of remarkable interpretations, which will be best illus- trated by a numerical example, which by the aid of logarithms may be worked out with great ease *. On Calculating Lunars. By Colonel SHORTREDE. Besides the trigonometrically rigorous methods of reducing lunars, there has been during the last ninety years a multitude of approximate methods more or less exact, and no lack of subsidiary Tables for facilitating the solution. The method here proposed is short and simple, and requires no subsidiary Tables beyond those of refraction and parallax, and the common Tables of logarithms to five places; and the result is always correct to within a quarter of a second. The corrections in altitude into the cosines of the adjacent angles give the prin- cipal corrections on the apparent distance. We cannot from the given altitudes and distance get the cosines directly, but we find them by means of the versines. The right-angled triangles formed by perpendiculars from the true places to the apparent distance being calculated as plane triangles, the greatest possible error on the moon’s correction cannot exceed 0'"4. The smaller segment of the true distance is found by means of the logs used in finding the principal corrections, using as a first approximation the reduced or cur- tate distance instead of the greater segment. The cotangent of the greater segment to three places requires to be found; for the cot of the smaller segment we may use the complement of its log sine. The squares of the perpendiculars are found by taking the product of the sum and difference of the corrections in altitude and in distance. Logs to five places are required for the principal correction of the moon; for the other parts of the work, logs to three places will ordinarily suffice. For the error on Muy as above found. tan Mu=tan Mm.cosm, Mp+ Mut + &e.=005 M(Mm-+ Me + &c. it 3 3 Mpu—Mm cos M= se cos M— — 3 3 = Mm cos M— Mm cos® M 3 3 3 = Mm cos M sin? M. For secondary corrections. cos .cosp=cosh=cos (b+d) =cosb cos d—sin b sin d, sin 6 sin d=cos b (cos d— cos p) = cos b. 2 sin = : sin? sin d=cot b (vers p—vers d) =2 sin? 4p cot b—cot 6 vers d, inl! — aoe p' cot b— &c. * The above paper is published at length in the Philosophical Magazine for November 1859, and in the Assurance Magazine for January 1860. : ; TRANSACTIONS OF THE SECTIONS, or For segments of true distance. sin Mm.sinM__ sin Ss.sin§ sin l= sin Im sin Is : sinSs.sinS , sinSo.sinZM , sin Is= sin Mmsia M S12 In= sin’ -sin ZS 8 In __Ss.cosA , ile er (ms—Is). On the Figure of an imperfectly Elastic Fluid. By Professor Hennessy, PRS. It appears that the shape of a mass of such a fluid is dependent on its volume in such a way that any abstraction from or addition to that volume will in general be attended with a change of figure. This proposition, when applied to the case of a mass in rotation, shows that if the earth has gradually passed into its present state from one of complete fluidity, the figure of the inner surface of the consolidated crust must be more elliptical than the stratum of fluid out of which it was formed. The actual amount by which the ellipticity would be so increased would depend upon the law of density of the fluid, but the general result of an increase in the value of the ellipticity is completely independent of the law of density, and of any hypothesis as to the constitution of the interior fluid mass. Note on the Calculus of Variations. By Professor Linve or, of the University of Helsingfors. In the problems with which the calculus of variations is concerned, it becomes necessary to regard the form of certain unknown functions as variable and capable of passing from any given form to any other in a continuous manner. The only way of rigorously establishing this indispensable continuity appears to be that followed by the illustrious Euler, that is to say, by the introduction of an arbitrary and vari- able parameter. The function which ought to vary, or rather change its form, is then regarded as a particular value of a more general function, which, besides the principal variables, also involves an arbitrary parameter, and the variation of the function is nothing more than its differential taken with respect to this parameter. The calculus of variations has thus become a simple application of the differential calculus to the case where the function to be differentiated is a definite integral. The first problem which presents itself is to find the variation of the given integral, in other words, to differentiate the integral with respect to a parameter which it may contain in any manner whatever. This first problem has gradually received its complete solution through the researches of Euler, Poisson, and Ostrogradsky. But the moment we attempt to pass to the applications of the calculus we encounter a second, and more difficult problem, which for a long time has resisted the efforts of the greatest mathematicians ; it consists in preparing the variation so that all its parts may be examined, in other words, so that the equations relative to the limits of the integral may be found. This preparation necessitates a series of partial in- tegrations. Now the limits of the variables which, after the integrations, must be substituted for the variables themselves are so mixed up with each other, and with the variables themselves, that it appears impossible to take them into account by means of the system of notation in general use. This difficulty has at length been happily overcome by an expedient, at once in- genious and simple, due to M. Sarrus of Strasburg. In a memoir to which the Parisian Academy of Sciences awarded a prize, M. Sarrus has introduced a new symbol to indicate the substitutions to be made in any expression, and by means of this symbol he has been able, not only to find the variation of a multiple integral, but to examine the same completely. We may add that Cauchy, in a memoir on the calculus of variations which he was never able to finish, adopts the innovation introduced by M. Sarrus, after slightly modifying the symbol of substitution in order 6 REPORT—1859. to render it more accordant with the symbols of integration with which it is involved in researches of this kind. My sole object in recalling these well-known facts has been to indicate the starting-point of my own researches on the calculus of variations, a few of whose results I have now the honour to communicate. Following the example of M. Sarrus, I apply the term definite expression to any function whatever in which fixed values have been substituted for all the indepen- dent variables. Such a definite expression is no longer a function of these variables ; it depends solely upon the parameters, that is to say upon the indeterminate con- stants, which it happens to contain. It is at once seen that every definite integral possesses this property, the variables themselves being therein replaced by certain limiting values. In order to indicate, in other expressions, that a certain variable must be replaced by a particular value, we shall employ the symbol | ; so that neon, 2, i | u, or simply | « denotes the result obtained by substituting the value «,, in place of the variable a, in the expression wv. In conformity with the notation of the integral calculus, the same symbol will also serve to denote the difference between the results obtained by two different substitutions. Thus the notation x=, , u, or simply u 2=2, 2, denotes that the variable must be successively replaced by x, and #, and the first resu!t subtracted from the second; so that vy x, a) u. | u=;uU- | v7 The definition of a definite expression may now be more precisely expressed thus : it is a function submitted to integrations or to substitutions with respect to each of its independent variables. Such an expression is invariable so long as the constants which it contains preserve the same fixed values. But if it should contain an inde- terminate parameter whose value changes, the expression in question will become a function of that parameter, and under this point of view may be differentiated. This being granted, the most general problem of the calculus of variations, the problem in which, in fact, the whole theory of this calculus is contained, consists in finding the derived-function of any definite expression with respect to a variable parameter. M. Sarrus, it is true, has rendered the determination of this derived function possible in every particular case, but neither he nor Cauchy has given a general rule of differentiation applicable to every definite expression. I believe I have established this rule, and in the following manner. Let us suppose the function V, containing any number of independent variables , @, Y, 2, 5.00 3, Tt, 5 to be subjected to integrations or substitutions with reference, successively, to cach of the variables according to the inverse order of their enumeration ; so that the first operation shall refer to ¢, the second to s, and so on up to the last, which shall have reference to x. Further, let *, Zyy eee Sy, be the inferior, and allie ih Loy Yor Zaye + + Bas Ly the superior limits of these variables. _ The limits ¢, and ¢, of the variable ¢ may be functions of x, y, %, ...... 8, but they- TRANSACTIONS OF THE SECTIONS. 7 must be independent of ¢. Similarly, the limits of the variable s may be functions of all the variables a, y, z.... which precede it, and so on up to the variable x whose limits are independent of all the variables. The result of these operations will be a definite expression, which, for brevity, may be represented by OV. It is required to find the derived function of OV with respect to a parameter ¢, which may at the same time be contained in V and in all the limits of the variables. For brevity we employ the symbols x x. 1 p Yi y 4 de, fae, fou, fy fy Pe da’ da’ da’ da’ dx’ dz"***** as defined by the equations Xy By dx = det, dx — da, da da’ du ba de’ nh Yo A Ma NE a. da de’ 7 ne hg pl Ye dy — dy, dy = dy, & dz dx” 7 ape ia This will clearly give rise to no error, since the expressions de de dy dz dx’ da’ have, in themselves, no meaning whatever. This being admitted, the general rule at which I have arrived may be thus enunciated. In order to differentiate any definite expression with respect to a variable para- meter «, neglect, in the first place, all the symbols of substitution and take the derived function of the remaining integral, treating the variables to which the above substitutions refer, as if each were a function of all the preceding ones and of #; in each term of the result restore the symbols of substitution before withdrawn. From the symbolical form which is thus obtained the true expression of the required de- rived function may be immediately obtained. In order to illustrate the application of this rule, let us seek the derived func- tion, with respect to ~, of the expression eee vy Yo Bo Hehe | Vay. x 9% Neglecting, in the first place, the symbols of substitution, we must differentiate the integral Ys { Vdy; "1 its derived function with respect to « is, according to the formula of M. Sarrus, Y2 1dV Yr (dy, 9i_ 7g, aN aya) _ v(54). ( (7)a+ ie (2) | du re ' . Now since-# and % are the variables to which the neglected symbols of substitu- tion refer, we must, on differentiating, proceed as if each of the three variables #, x, % were a function of those which precede it; that is to say, we must consider 8 REPORT—1859. z as a function of « and a, and # asa function of «. For the total derived func- tions, therefore, we shall have the values eS _dV dV dx (2! dz “4 da! de dx de dz\de dx dz!’ (#)= = 1 4 My de dx da) dw dx de’ (#)= = Mo, da da! de dx de By introducing these values into the preceding expression, and afterwards re-esta- blishing the symbols of substitution before withdrawn, we arrive at the symbolical formula v, 2 Zo vel fo] { Ge aN dV = ee) \ P, are “da de dxda EON, Eh ® Yo 2 VY) 2 +] | [oetea)-| | [vGe-24) | de “de da dx da)’ x, %y Bee By . V : In order to deduce the true expression for , we must decompose, successively, the triple symbols of substitution into simple ones, and afterwards replace the sym- bolical derived functions ae = Be by the real ones which they represent, and da’ da dx which are determined by a prefixed symbol of substitution. This rule serves to effectuate with facility all the reductions which have to be applied to the variation of an integral; but to enter into further details at presert would be to demand too much from the patience of this illustrious assembly. I shall merely add a short remark relative to the application of the calculus of variations to the investigation of the maxima and minima of definite integrals. In seeking the absolute maximum or minimum of any integral S, containing one or more unknown functions, it is merely necessary to introduce into these functions an arbitrary parameter « in order to reduce the problem to that of finding the maximum or minimum of a given function. In fact, by so doing, the integral S becomes a function of «, and its maximum or minimum is determined from the equation dS _3S=0. a But if, at the same time, certain other integrals S,, S,, &c.... are required to pre- serve the constant values S, = ¢,, S,=6., &C...+0 during the variation of the unknown functions, the method just indicated does not suffice. In this case, which notwithstanding its frequent occurrence has scarcely ever yet been treated ia a sufficiently rigorous manner, the result may be arrived at by a very simple expedient. Into each of the unknown functions let a number of parameters a, 8, y ... equal to the number of integrals S, 8,, S,... be introduced ; these integrals, ivtiiol thus become functions of the parameters, may then be repre- sented by S= («,B,y.. “5 8, => (2,8, y.. SF Ss, = x (a, B, ys. SF Corse and it now remains to find, amongst all the values of «, Bs yevces which render BS, HC), Sy =C, «2.000 , those which correspond to a maximum or minimum of S. Ac- cording to the known principles of the differential calculus, it will suffice, therefore, to find the absolute maximum or minimum of the sum STS ik AS TRANSACTIONS OF THE SECTIONS. 9 where a, b...... are arbitrary constants to be afterwards determined by the condi- tions SC ya = Cay ecinnns This result is not new; it was in fact known to Euler, though he admitted that his own demonstration was not complete. I have never yet been able to find in other works a sufficiently rigorous demonstration of this method. On the Dynamical Theory of Gases. By Prof. J. C. MAxweEtt. The phenomena of the expansion of gases by heat, and their compression by press- ure, have been explained by Joule, Claussens, Herapath, &c., by the theory of their particles being in a state of rapid motion, the velocity depending on the temperature. These particles must not only strike against the sides of the vessel, but against each other, and the calculation of their motions is therefore complicated. The author has established the following results :—1. The velocities of the particles are not uniform, but vary so that they deviate from the mean value by a law well known in the “ method of least squares.” 2. Two different sets of particles will distribute their velocities, so that their vires vive will be equal ; and this leads to the chemical law, that the equivalents of gases are proportional to their specific gravities. 3. From Prof. Stokes’s experiments on friction in air, it appears that the distance travelled by a particle between consecutive collisions is about math of an inch, the mean ? velocity being about 1505 feet per second; and therefore each particle makes 8,077,200,000 collisions per second. 4. The laws of the diffusion of gases, as established by the Master of the Mint, are deduced from this theory, and the absolute rate of diffusion through an opening can be calculated. The author intends to apply his mathematical methods to the explanation on this hypothesis of the propagation of sound, and expects some light on the mysterious question of the absolute number of such particles in a given mass. Supplement to Newton’s Method of resolving Equations. By the Abbé Moreno. This was a mathematical paper, showing a method of greatly shortening and facilitating the finding of the roots of equations of a high order by the method of limits. Note on the Propagation of Waves. By G. Jounstone Stoney, JLA., WRIA. This communication aimed at introducing less imperfect geometrical conceptions into the study of wave propagation, than those commonly applied. Each element of the front of a wave has been usually taken as the origin of a spherical disturbance, and the subsequent position of the wave simply regarded as the envelope of all such shells. This mode of treatment has the disadvantage of so imperfectly representing the phenomena, that it leads to great embarrassments. ‘Thus it leaves the direction in which waves are propagated enveloped in great mystery, and most of the methods which have been suggested by geometers for removing the obscurity have failed to be satisfactory. The difficulty at once vanishes if we fix our attention in the first instance on the element whose disturbance at a given moment we wish to determine, and consider, along with its previous condition, all the influences which reach it at that moment. A spherical shell described round this disturbed element as centre, will in general (if the medium be homogeneous, &c.) pass through points from which the influence had started simultaneously ; and if the entire series of such shells be considered, as well as the time at which the influence from each must have been thrown off to reach the common centre at the same moment, it will be easily seen, that, roughly speaking, the parts of the medium behind the disturbed centre were to a considerable distance in the same or nearly the same phase when they contributed to its disturbance, whereas those parts in front of it were in rapidly succeeding phases. From this it follows that the influences arriving from behind will have a great preponderating resyltant in one direction, while those arriving from the parts 10 REPORT—1859. in front will almost cancel one another. This clears up at once the maintenance of the onward propagation of an undulation. The points of the medium, which were in strictly the same phase as the disturbed element when they transmitted their influence, lie in general (on the hypothesis of homogeneity, &c.) on a surface of revolution round the wave-normal, and passing through the disturbed point. This surface of revolution (which, if we make the simplest hypotheses, becomes a right cone) is of importance in the theory of waves. If the medium be such that the disturbing influence is but little enfeebled by di- stance, this cone will obviously be of small angle, and therefore nearly coincide with the backward part of the wave-normal. In such a medium waves will therefore spread but little laterally. A constitution of this kind probably contributes materially to the rectilinear propagation of light, and explains a phenomenon which shows that the common account does not universally hold, viz. the known fact that sound in water bends with less facility round obstacles than sound in air, although the waves constituting it are longer. It is necessary to form a clear conception of what is to be understood by the in- fluence contributed by an element of the medium. The parts beyond one of the spherical shells produce an effect on the central disturbance. - This effect is modified by the particular condition in which that shell was at some time previous to the central disturbance. It is this modification which is to be regarded as the influence of that shell; and so of the rest. The resultant is therefore to be obtained by inte- grating from without inwards. After the conditions which must be attended to when the influence is transmitted from each origin of disturbance with unequal speed in different directions, or is not at a given moment limited to a surface, &c., were referred to, some applications of the method to familiar phenomena which do not admit of easy explanation by the usual methods, were given. On the Relations of a Cirele inscribed in a Square. By J. Smitu. On the Angles of Dock-Gates and the Cells of Bees. By C. M. Wiixicu. The author showed by trisection of the cube along different planes, the produc- tion of various solids, and the relation of these to natural forms known in cry- stallography, to the bee’s cell, and to the theoretical meeting angle of dock-gates (109° 28' 16”). Thus a rhomboidal dodecahedron is composed of four rhombo- hedra. The bee’s cell may be imitated by an elongated dodecahedron composed of seven rhombohedra. Licut, Heat, ELectricity, MAGNETISM. On a New Species of Double Refraction. By Sir Davip Brewster, K.M., LL.D., FERS. In 1813 Sir David Brewster discovered that when a ray of light is transmitted obliquely through a bundle of glass plates it is completely polarized; but he at the same time noticed that this beam is accompanied with other rays, sometimes nebulous, and sometimes in separate distinct images (depending on the polish and parallelism of the glass), but polarized in an opposite plane*. This fact was overlooked by Arago and Herschel in their subsequent researches on the same subject, and was not further pursued by Sir David Brewster at the time. In recently examining, however, several hundred films of decomposed glass of extreme thinness, on which the polish and parallelism of the surfaces enabled him to resume the study of the compound beam, he obtained the following results :— 1. When a beam of polarized light is incident obliquely upon a pile of thin and homogeneous uncrystallized films, and subsequently analysed, the transmitted light will exhibit the phenomena of negative uniaxal crystals, that is, it will consist of two * See Phil. Trans. 1814, p. 225-230. TRANSACTIONS OF THE SECTIONS. 11 oppositely polarized pencils, which produce by interference all the colours exhibited by such crystals under similar circumstances. ) 2. The two oppositely polarized pencils are, first, the pencil polarized by refraction at each surface ; and secondly, the pencil, or rather the fasciculus of pencils reflected from the surfaces of each film, and returned into the transmitted beam, As these phenomena are exactly the same as those produced by double refraction, the author did not hesitate to call the result a new species of double refraction, or a hew process in which the phenomena of double refraction are produced. On the Decomposed Glass found at Nineveh and other places. By Sir Daviv Brewster, K.H., LL.D. FURS. The author described the general appearance of glass in an extreme state of decom- position, when the decomposed part was so rotten as to break easily between the fingers, a piece of undecomposed glass being generally found in the middle of the plate. He then explained how, in other specimens, the decomposition took place around one, two, or more points, forming hemispherical cups, which exhibit the black cross and the tints of polarized light produced by the interference of the reflected with the transmitted pencils. In illustration of this decomposition, he showed to the Meeting three specimens, in one of which there was no colour, but which consisted of innu- merable circular cavities with the black cross, these cavities giving it the appearance of ground-glass. In another specimen the film was specular and of great beauty, showing the complementary colours by reflected and transmitted light. Ina third variety the films were filled with circular cavities exhibiting the most beautiful colours, both in common and polarized light. Various other remarkable properties of these films were described by the author. On the Submergence of Telegraph Cables. By H. Cox. On the Stratified Electrical Discharge, as affected by a Moveable Glass Ball. By J. P. Gassiot, F.R.S, If the discharges from an induction coil, when taken in a good carbonic acid va- cuum tube, are examined with care, it will be seen that the stratifications nearer the negative terminal are remarkably clear and defined, oftentimes showing clearly sepa- rated cloud-like luminosities, but gradually becoming indistinct and intermingled with each other towards the positive terminal wire. This difference in the character of the stratified discharge becomes more perceptible to a certain extent as the vacuum im- proves ; for when the stratifications are close and narrow, they are regularly diffused throughout the entire length of the luminous discharge. In a tube 18 inches long and J} inch wide , I inserted a small bead of uranium glass about + of an inch in diameter. Transparent uranium glass, Professor Stokes has shown has the property of becoming opake by the electric light, and this is very beaus tifully shown in these tubes, but more particularly when the negative discharge is made to impinge on the bead. If during the discharges the tube is inclined so as to permit the bead to roll down, the discharges will give the appearance as if a distinct row of separated beads were present; this appearance arises from the number of dis- charges which take place during the rotation, each discharge separately and distinctly illuminating the bead. The peculiar phenomenon which I, however, desire to bring before the notice of the Section is one which I only very recently noticed. I have already stated that the stratifications near the positive wire are indistinct ; but if the glass bead is placed near the positive wire and then allowed slowly to descend towards the negative, the stratifications at the positive are at first as clearly defined near that terminal as at the negative, and as the bead rolls gently down, they have the appearance of following the bead and issuing one after the other from the positive wire, until the bead reaches to within a few inches of the negative, when this action gradually ceases. If the tube is now inclined so as to allow the glass bead to return in the contrary direction, the stratifications appear to recede, becoming more and more clearly defined, until the bead passes the positive terminal wire, when the entire discharge returns to its normal state. — 12 REPORT—1859. On the Relation between Refractive Index and Volume among Liquids. By the Rev. T. P. Dare and J. H. Giansrone, Ph.D., FR. The authors referred to a previous paper, in which they had shown, among other things, that the sensitiveness of a substance is not directly proportional to the change of density produced by an alteration of temperature. The theoretical formule re- lating to the dispersion of light afford little assistance in determining what this rela- tion is, but a series of careful observations had been made with a view of arriving at some empirical formula. It was found that the product of the volume, reckoned as 1000 at the boiling-point, and the refractive index for the line A of the prismatic spectrum less unity, gave numbers which were nearly constant. In the case of water, alcohol, pure wood-spirit, and bisulphide of carbon, however, the volume increases a little faster in proportion than the refractive index less unity diminishes, while with ether the reverse is the case. The regularity of the numbers shows that this is not due to errors of experim nt. The authors propose examining the subject more closely. On the Theory of Light. By G. F. HarRincTon. Notice of Experiments on the Heat developed by Friction in Air. By J. P. Joure, LL.D. ERS. The research which Professor Thomson and myself have undertaken on the ther- mal effects of fluids in motion, naturally led us to examine the thermal phenomena experienced by a body in rapid motion through the air. The experiments which we first made for this purpose were of a very simple kind. We attached a string to the stem of a sensible thermometer, and whirled it alternately slowly and rapidly. In this way we uniformly obtained a slight effect; there was a higher temperature observed immediately after rapid, than after slow whirling. A thermo-electric junction rapidly whirled also gave us an appreciable thermal effect, indicated by the defiection of the needle of a galvanometer. Afterwards a more accurate set of experiments was made by us; using a lathe, to the spindle of which an arm was attached carrying one of Professor Thomson’s delicate ether or chloroform thermometers. The thermometers employed were so extremely sensitive that each division of their scales had a value of not more than aha of a degree Centigrade. The great value of Professor Thomson’s thermo- meters in the whirling experiments, was further enhanced by the light specific gravity of ether comparatively with mercury : the pressure produced by centrifugal force ope- rating on a long column of mercury, would have probably broken a mercurial thermometer whirled at high velocity. The results arrived at by Professor Thomson and myself were as follow :— lst. The rise of temperature in the whirled thermometer was, except at very slow velocities, proportional to the square of the velocity. 2nd. The velocity at which the bulb had to travel in order that its temperature should be raised 1° Cent. was 182 feet per second. 31d. At very slow velocities the quantity of thermal effect appeared to be some- what greater than that due from the square of the velocity calculated from the above datum; and we surmised that this was owing to a sort of fluid friction different from the source of resistance at high velocities. We therefore made several attempts to increase this fluid friction; the most successful result being obtained by wrapping fine wire over the bulbs. By this means we succeeded in obtaining the 1? from a velocity of 30 feet per second, a quantity five or six times as great as that which took place when the naked bulb was revolved at the same velocity. We resumed the whirling experiments last May; and it is owing to the circum- stance that it has happened that I have myself been principally engaged in making those which I am about to communicate to the Section, that Professor Thomson has requested me to give an account of this part of our joint labours. Our object was to repeat the former experiments under new circumstances, so as to verify and extend the results already obtained. A very brief outline can only be given in this place, as we intend shortly to incorporate them in a joint paper for the Royal Society, to whose assistance we owe the means of prosecuting the inquiry. TRANSACTIONS OF THE SECTIONS. 13 The lathe was again used as the whirling apparatus, but instead of the ether ther- mometer, we whirled thermo-electric junctions of iron and copper wires. We obtained the following results :— 1st. The law of the thermal effect was, as with the ether thermometer, proportional to the square of the velocity. 2nd. The rise of temperature was independent of the thickness of the wire which formed the thermo-electric junction which was whirled. This was decided by experi- ments on wires of various diameters, ranging from ;1, to + of aninch diameter. The rise of temperature was in any of the wires the same as that obtained with the ether thermometer, the bulb of which was nearly half an inch in diameter. 3rd. The thermal effect appeared likewise to be independent of the shape of the whirled body ; little difference happening in whatever direction the wire was placed. 4th. The average result was that the wire was warmed 1° by moving at the velocity of 175 feet per second. The highest velocity obtained was 372 feet per second, which gave a rise of 5°’3, and there was no reason to doubt that the thermal effect would go on continually in- creasing according to the same law with the velocity. Thus ata mile per second the rise of temperature would be 900°, and at 20 miles per second, which may be taken ° as the velocity with which meteors strike the atmosphere of the earth, 360,000°. The temperature due to the stoppage of air at the velocity of 143 feet per second is one degree. Hence we may infer that the rise observed in the experiments was that due to the stoppage of air, less a small quantity, of which probably the greater part is owing to loss from radiation. It being also clear that the effect is indepen- dent of the density of the air, there remains no doubt whatever as to the real nature of “shooting stars.’’ These are small bodies which come into the earth’s atmo- sphere at velocities of perhaps 20 miles per second. The instant they touch the atmo- sphere their surfaces are immediately heated far beyond the point of fusion, or even of volatilization, and the consequence is that they are speedily and completely burnt down and reduced to impalpable oxides. It is thus that, by the seemingly in- sufficient resistance of the atmosphere, Providence secures us effectually from a bombardment which would in all probability speedily destroy all animated nature, with the exception of the fishes, which would be partly, but not altogether, protected by the water in which they swim. The experiments to carry out and verify our previous results on the thermal effects which appear to belong to friction on large surfaces at slow velocities were made as follows :—A disc of zinc or card-board was attached to the revolving axis. An ether thermometer was attached to the disc, the bulb being near the circumference and describing a circle with a radius of about 13 foot. Onrotating the disc at the velocity of 12 foot per second, as much as one-thirtieth of a degree of heat was developed. On the Transmission of Electricity through Water. By J. B. Linpsay. The author has been engaged in experimenting on the subject, and in lecturing on it in Dundee, Glasgow, and other places since 1831. He has succeeded in transmit- ting signals across the Tay, and other sheets of water, by the aid of the water alone, as a means of joining the stations. His method is to immerse two large plates con- nected by wires at each side of the sheet of water, and as nearly opposite to each other as possible. The wire on the side from which the message is to be sent is to include the galvanic battery and the commutator or other apparatus for giving the signal. The wire connecting the two plates at the receiving station is to include an induction coil or other apparatus for increasing the intensity and the recording apparatus. The distance between these plates he distinguished by the term “ lateral distance.” He found that there was always some fractional part of the power from the battery sent across the water. There were four elements on which he found the strength of the transmitted current to depend : first, the battery power; second, the extent of surface of the immersed metal sheets; third, the “ lateral distance’ of the immersed sheets; and, fourth, in an inverse proportion the transverse distance or distance through the water. As far as his experiments led him to a conclusion, doubling avy one of the former three doubled the distance of transmission. If, then, doubling all would increase the intensity of the transmitted current eightfold, he entered into calculations to show that two stations in Britain, one in Cornwall and 14 REPORT—1859, the other in Scotland, and corresponding stations well chosen in America, would enable us to transmit messages across the Atlantic, On the Affections of Polarized Light reflected and transmitted by thin Plates. By the Rev. H. Luoyp, D.D., F.RS. When plane- polarized light is incident upon a thin plate, the reflected and trans- mitted pencils are, in general, elliptically polarized. 'This fact was pointed out by the author many years ago, as a result of theory; and it appears to furnish the explanation of the phenomena recently observed by Sir David Brewster, and to which he has called the attention of the Members of this Section. In the present commu- nication the author proceeds to develope this theoretical result, and to deduce the laws according to which the elliptical polarization varies, as well with the thickness of the plate, as with the incidence. When light incident upon a thin plate is polarized either in the plane of incidence, or in the perpendicular plane, it will continue polarized in the same plane, after the successive reflexions and refractions which it undergoes at the two surfaces of the ‘plate; and we have only to seek the magnitude of the resultant vibration. The problem is different, however, when the light is polarized in any other plane. In this case the incident vibration must be resolved into two, in the two principal planes, and for each of these components we must know the phases, as well as the magnitudes, of the resultant vibrations, before we can estimate their joint effect. As these phases are in general different, the resulting light is elliptically polarized. When the media are the same on the two sides of the plate, the difference of phase of the two component vibrations (upon which the character of the resulting light mainly depends) is given by the formula (v?— w’) sin a tan A= E 3 1—(v?+w?) cos 2+ 07w?’ in which @ is the phase due to the retardation of the wave, which has passed once to and fro within the plate; and v and w the coefficients of the reflected vibrations, for light polarized in the plane of incidence, and in the perpendicular plane, respect- ively. It follows from this, that A varies with we, and therefore with the thickness of the plate; and that, in the phenomena of the rings, it will go through all its values within the limits of each ring. A vanishes, when «=m7z, i.e. both at the bright, and at the dark rings; and accordingly the light at the former is plane-polarized. On the other hand, A is a maximum, relatively to the thickness of the plate, when vw 1+v7w?? and the maximum value is given by the formula cos ¢= v2—w? ¥ V (l=) (1—w!) Substituting for v and w their well-known values in the former of these formule, we find tan A= 4 cot¥S= (ut p—1)+ (p—p-1)?; in which p is the refractive index, and p the ratio of the cosines of incidence and refraction. It follows from this, that cots increases, from 2 (u+p- at a perpen- dicular incidence, to infinity when the incidence is most oblique; and that, in a plate of varying thickness, the points of maximum difference of phase commence near the middle of an interval, and approach indefinitely to the dark rings as the incidence approaches to 90°. A similar discussion of the second formula shows that the maximum difference of phase increases continuously with the incidence, being nothing at a perpendicular inci- TRANSACTIONS OF THE SECTIONS. 15 dence, and greatest when the incidence is most oblique. The absolute maximum is given by the formula cot caoh 9 (Pee For ordinary flint-glass, A=26° 0’. The difference of phase in the two component portions of the polarized beam is the same in the reflected and in the transmitted pencils. There is no difficulty in extending the investigation to the more general case, in which the media on the two sides of the plate are of unequal refractive densities ; but in this case the law last stated no longer holds. The general formule for the intensity explain not only the phenomena observed by Arago and by Sir David Brew- ster, but likewise indicate some results hitherto unnoticed. On the Mixture of the Colours of the Spectrum. By Prof. J.C. Maxwett. The author described his apparatus for obtaining a uniform field, illuminated by the light of any one or more definite portions of the spectrum, and comparing this mixture with a field of white light in contact with it. The experiments consisted in obtaining perfect equality between a combination of three definite portions of the spectrum and this white light. The relations of these portions are then ascertained by mathematical treatment of the equations so obtained, and it results that Newton’s “circle of colours ”’ is found to be really two sides of a triangle; red, yellow-green, and blue being the angular points, and yellow being on the side between red and green, The extreme red and violet form small portions of the third side, of which the middle part representing purple is wanting in the spectrum. The peculiar dimness of the spectrum near the line F, as described to the Section in 1856, was further investigated, and shown to be more marked to the author’s eye- sight than to that of others. It results from this that a mixture may be formed, which appears green to one eye and red to another, and this was found experimentally true. These results are only part of a complete investigation of the colours of the spec- trum, of which the experimental portion is considerably advanced and will shortly be published. On certain Laws of Chromatic Dispersion. By Muneco Ponton, F.R.S.A. This paper is an attempt to trace the laws regulating the diminution of the wave- lengths, corresponding to the fixed lines of Fraunhofer, in passing through various refractive and dispersive media. If U be the length of the undulation, corresponding to any line, in the free ether, and wu its length after being subjected to the action of the medium, the relation between U and u may be expressed thus : are +a=u, or € e(ut+et+tx)=U. Here cand are constant for the medium and temperature, while the quantity 2, which is comparatively small, is peculiar to each wave. These quantities 2 represent that displacement or extrusion of the fixed lines, from their normal relative positions in the pure diffracted spectrum, which constitutes the irrationality of the various refracted spectra; and they are accordingly termed the ewtrusions of the fixed lines, Thus each medium is regarded as having a refractive, a dispersive, and an extrusive power, peculiar to itself at a given temperature. The constant ¢ is found thus: B, C, D, &c. representing the normal wave-lengths corresponding to the fixed lines, and 6, c, d, &c. these wave-lengths after refraction, calling (3 B+2C+D)—(F+2G+3H)=A and (3)+2¢+d)— (f+2g+3h)=6, then is Bie é The constant & is found thus: S being the sum of the normal wave-lengths cor- responding to the 7 lines, and s their sum after refraction, then is a=} (5—»). € The values of « and of log ¢ for the different media are given in Table I, 16 REPORT—1859. From these two constants, a second series of refracted wave-lengths may be calcu- B C lated, thus: ~—e#=b,, -—#=c, &e., which will represent what the refracted wave- lengths would be, were the medium free from irrationality. This series is presented in Table III.; and from it, compared with the series found by observation, as ex- hibited in Table II., the values of x, or the extrusions for the different media, are deduced, as exhibited in Table IV. In the larger proportion of the media which have been examined, these quantities x are governed by certain determinate laws. The departures from these laws, pre- sented by several media, are shown to be traceable to errors of observation ; and they wholly disappear when the numbers are brought under the dominion of the more general law, subsequently determined. Then only two exceptions remain— the solution of muriate of zinc, and the oil of cassia. The discrepancy, in the for- mer case, it is suggested, is probably due to errors which the observer himself (Powell) suspects to exist in his determinations,—the discrepancy in the case of the oil of cassia being probably traceable to a similar cause. The extrusive force, on which the irrationality depends, exhibits itself in the form of a transfer of motive energy, from the terminal to the central parts of the spectrum. The undulations, corresponding to the lines D, E, and F, are a little less retarded than they would otherwise be, and their wave-lengths within the medium are accord- U ingly a little less shortened. Hence for D, E, and F the formula is TT ety =U. The undulations, corresponding to B, C, G, and H, are a little more retarded than they would otherwise be, and their wave-lengths within the medium more shortened; pad si : so that for these four the formula is Tea aU, the positive and negative values of x balancing each other. Hence twice their sum, or 2X, is reckoned the measure of the extrusive power of the medium. Every medium accordingly presents two nodes where the extrusion is nil and passes from positive to negative. The upper node lies between C and D, and pro- bably occupies the position of the mean wave; the lower lies between F and G, and near G. The only permanent exception is the oil of cassia, in which the lower node falls a little below G. All regular media present the following relation : (3bx-+ 2ce— dz) = (3hx+292—fe). It is proposed to call this “‘ the Semel-bis-ter law.” Hence, if K=(B+C+G-+H) —(D+E+F) and Q=(d+ce+9+h)—(+e+f), the extrusive power may be ex- K pressed thus : fea: (Q+a+2X)=0. If the extrusions be taken in pairs, equidistant from the centre e,, and if the dif- ference between bx and hy be denoted by 6, that between cx and gz by 6, and that between d, and fz by 6,, then the differences between each pair of these three quan- tities 6,, 5,, and 6, constitute a progression of the form ¢, 2¢, 3¢, the quantity ¢ vary- ing with the medium and temperature. It is proposed to call this “the law of the equicentral common difference.” The series of refracted wave-lengths 6,, c,, d,, &c. having been calculated, as in Table III., the refractive indices corresponding to them may be found from the formula 2 =,B, =p, C, &c. This series of indices «, B, w, C, &c. is what the medium would present, had it no extrusive power ; and the differences between these and the observed indices show what portion of the latter is due to that property. These two sets of indices present nodes, corresponding to those of the extrusions ; and it is shown to be a general law, that the refractive indices, corresponding to the nodes of the extrusions, coincide with the nodes of the two sets of refractive indices. It is proposed to call this “the law of coincident nodes.” The apparent exceptions to these laws are then pointed out, and the probability of their being all due to errors of observation is discussed. The product of the two constants, or ew, deducted from each of the normal wave- lengths, shows how much each normal is shortened in passing through the medium, TRANSACTIONS OF TIE SECTIONS. 17 from the operation of the dispersive power alone. The actual loss of length, being represented by ez, is the same for all waves ; consequently it tells more on those waves which are primarily shorter. Hence the numbers representing the loss of length sustained by each wave in proportion to its primary length, from the ope- ration of the dispersive power alone, are in inverse proportion to the primary wave- lengths. These rateable losses of wave-length, multiplied by the second series of refractive indices ~, B, «,C, &c., exhibit the proportion of each index due to the dispersive power alone. ‘These points are exemplified by the case of the bisulphuret of carbon. In different media, the loss of length, sustained by any one wave through the operation of the dispersive power alone, is proportional to the constant «, which may accordingly be regarded as its measure. The effects of change of temperature are illustrated by the two cases of oil of anise, and oil of cassia, for which alone sufficient experimental data exist ; and it is shown to be probable, that, in the same medium, the values of ¢ are in the inverse orders of the temperatures, and their differences proportional to the differences of temperature ; also that, in different media, in which the value of ¢€ is nearly the same, the fall in that value is proportional to the rise of temperature. The constants ¢ and a, being influenced only by the mutual relations of the extru- sions, and not by their absolute values, are consistent with an indefinite number of sets of indices of refraction; so that the indices may always be altered in a certain manner, without altering the constants. It is then shown, that the conservation of the total vis viva of the normal wave-lengths depends on the constants e and #, and a third constant 7, thus: ca{ B C D E F G H in venta) ribs Ss To find n, call the sum of the series 5 a ct &e. =5, and call sae, then is the difference between ez and ec. = a2 > #, then n is+; if 2 > e, then 7 is —, and in either case is constant for the medium and temperature. It is always pos- sible to find a positive value of X which shall render 7=0. Calling this limiting value 12 then is X=« ee The logarithm of this multiple of is 2°4216417. The effects of raising the normal wave-lengths to different powers are next examined. It is shown that, in every case, there is a certain power at which the extrusions are reduced to a minimum, and that these lowest values are so small that they may be referred to errors of observation. There is thus always a certain exponent, which may be applied to the normals, which will extinguish the extrusions, so rendering the relation between the wave-lengthd and its refractive index « capable of being expressed rz by this general formula: B= dat —en. This it is proposed to call ‘‘ the exponen- n tial law of dispersion.” The value of the exponent n depends on the relation which the irrationality bears to the dispersive power, or to the length of the spectrum. Expressing this relation thus, % =P» the following equation is universally applicable : - = constant. 1 By analysing the observations, the value of this constant is found to be nearly 0°0092593, and its reciprocal 10°8. These values are accordingly assumed, but sub- ject to future correction, Hence 11°8 is the highest limit of the value of m, being that which the medium would have if 2X=«. The lowest value of x, =1, subsists when #=0'0092593 and 2X =0. As the value of p may be obtained, with tolerable accuracy, from any set of observations which are approximately correct, the value of x» may be found from the a 10°8p+1=n with sufficient accuracy for calculating the indices; and it 59 18. # REPORT—1859. is unhecessary, in using this exponent, to go beyond the first place of decimals. The exponents for the various media, calculated from this equation, are given in Table I. The constants en and ep are determined from the nth power of the nor- mals, in the same manner as ¢ and are determined from their first power. These values are also given in Table I. The logarithms of the normals for each exponent from | to 3°5 are given in Table V., the normals adopted being those determined by the method explained in the separate paper on that subject. The indices of refraction for the various media, as calculated from the general for- n mula panes —«n, are given in Table VI.; the observed indices in Table VII. ; €n and the differences between the two in Table VIII. These tables are next minutely analysed, the observations being for this purpose classified. From this analysis it appears that, as respects the observations of Fraunhofer and Rudberg, the agreement between the observed and calculated indices is so close as to leave no doubt of the accuracy of this exponential law ; that as re- gards the larger proportion of Powell’s observations, the agreement is equally satis- factory ; but that in some of these the discrepancies are considerable. It is proved, however, by comparing the different observations together, that these discrepancies can be attributed only to errors of observation. For example, it is pointed out that while Fraunhofer’s two sets of observations on water agree almost perfectly with the law, Powell’s single observation on the same medium exhibits a yery consider- able discrepancy, which can be attributed to nothing but experimental error. It is next shown that Powell’s observation on oil of cassia at temp. 14° Cent. presents a discrepancy from the law scarcely exceeding that of his observation on water, so that it also may be fairly attributed to experimental error. But his observations on oil of cassia at temp. 10° and 25° present the greatest discrepancies of all from the law ; and this difference between the results obtained for the same medium at these different temperatures can be due to nothing but experimental errors, seeing it is the observa- tion at the intervening temperature that is least discordant with the law. Thus, if the larger discrepancies, in the case of the oil of cassia at the extreme temperatures, be traceable to errors of observation, all the smaller discrepancies in other media may be fairly attributed to the same cause. When the indices of all the media have been corrected by the exponential law, then the whole become quite regular, as respects the position of the nodes of the extrusions and the relations which these quantities bear to each other, with the single exception of the oil of cassia; and as considerable errors of observation are shown to exist in that case, it appears not improbable that this exception might be remoyed by a more careful repetition of the observations. The exponential Jaw is then contrasted with the hypothesis of M.Cauchy,—namely, “that the differences between the refractive indices of the medium are to each other, very nearly, as the differences between the reciprocals of the squares of the normal wave-lengths. Or the refractive indices are each composed of two terms, whereof one is constant for the medium and temperature, the other reciprocally proportional to the squares of the normal wave-lengths.”’ ‘The indices calculated by Powell on the basis of this law, are compared with those calculated on the basis of the expo- nential law, and the differences are presented in Table IX. The result is shown to be greatly in favour of the exponential law. In the case of Fraunhofer’s observa- tions, the rate in its favour, as compared with the law of M. Cauchy, is as 2 to 1; in Rudberg’s observations as 4 to 3, in Powell’s as 10 to 7, and on the aggregate nearly as 3 to 2. In the particular and important case of the bisulphuret of carbon, the rate exceeds 5 to 1. The two laws are next examined and compared, as respects their principle and physical interpretation. The law of M. Cauchy merges together all the three phe- nomena—the refraction, the dispersion, and the irrationality, as if they were all due to one and the same cause; and it seeks, by a general formula, to dispense with observation to a certain extent, and to find the refractive indices of four of the fixed lines, from those of the other three being given by observation. In the exponential sw, on the other hand, the refraction, the dispersion, and the irrationality are TRANSACTIONS OF THE SECTIONS. 19 regarded as distirict and independent phenomena, referable to different causes; in evidence of which it is remarked that a low refractive power may consist with a high dispersive and extrusive power, or vice versd. ‘I’o arrive with accuracy at the expo- hent of the normals for any medium and temperature, it is advisable to know, from observations on all the seven lines, made with an approximate degree of correctness, the refraction, the dispersion, and the irrationality ; seeing the exponent depends on the relation of the irrationality to the dispersion. A pretty close approximation to the value of the exponent and the two relative constants may be madé, from having given only the indices of the two extreme, and one of the central lines; and from these the other four indices might thus be found. But fhere is no advantage in proceeding in this imperfect manner. Observations on the whole seven lines can never be dispensed with in practice; and as these tend mutually to check.one another, it will always be found more expedient to take the whole seven into account in the determination of the exponent and.the constants. The exponential law should therefore be regarded less as a substitute for observation, than as a method of reducing the observations, when made within certain limits of accuracy, under the dominion of law, and of thus rendering their accuracy more perfect. The essential difference between the law of M. Cauchy and the exponen- tial law, then, is, that the latter substitutes a variable exponent, capable of determi- nation, for the squares of the normals employed in the former. . The constant ¢ represents the effects of the refractive power alone, such as they would appear in achromatic combinations of prisms. It shows how much the waves are shortened by the mere increased proximity of the ethereal particles, or centres of elasticity, within the medium ; and as it affects all the waves rateably, it may sub- sist without either dispersion or irrationality. Inso far as this property is concerned, the waves, on entering the medium, embrace, in their length, the same number of ethereal particles as they did in the free ether. The constant « represents the effects of the dispersive power alone, which is attributed to the medium increasing the persistence of the ethereal particles in their normal positions, beyond that degree in which it would be augmented by their mere mutual approximation. It is supposed that, by this action, a certain definite num- ber of ethereal particles are excluded from the length of each wave, so as to cause all of them to be harteuen by the same definite amount. Thus the shorter waves are more shortened, in proportion to their primary length, than are the longer waves, These consequently exhibit unequal degrees of refrangibility, and are accordingly, on issuing from the medium, dispersed. , 5 Bead In explanation of the extrusive property, to which the irrationality is attributed, two views are suggested. Evidencing, as they do, an apparent transfer of motive energy from the extreme to the central parts of the spectrum, so that the central waves are less refracted, and the extreme waves more refracted, than they would otherwise be, the effects of the extrusive power present, as respects distribution, a conformity with the degrees of brightness of the spectrum; for all spectra are brighter towards the centre, and fade off on either side. This circumstance indicates that, at the recipient surface, the amplitudes of the individual vibrations embraced in the waves are greatest towards the centre. Now the action of the medium may be such as to lessen the amplitude of the vibrations, in all the waves, by a certain definite amount—the rapidity of vibration (consequently the refrangibility of the wave) being increased in the same proportion. But the waves whose individual vibrations have the greatest amplitude will, by such a constant force, be less affected, in proportion to the primary amplitude, than are the waves whose individual vibrations are of ‘smaller amplitude. The consequence will be, that the latter will appear to have their refrangibility increased in a slightly greater degree than the former; so that the waves corresponding to the lines B, C, G, and H will be further removed towards the violet extremity of the spectrum, and those corresponding to the lines D, E, and F less removed towards that extremity, than they would be in the absence of the extrusive property.” As an alternative to this view, it is suggested that these slight alterations in the rapidity of the individual vibrations may be due to a sympathetic action between the vibrations of the ponderable atoms of the medium and those of the ethereal par- ticles, resembling the sympathy of pendulums, in virtue of which some of the latter. Ox 20 REPORT—1859. are slightly increased, and others slightly diminished in rapidity, beyond what they would otherwise be. In conclusion, the attention of the British Association is invited to the unsatis- factory state of a considerable number of the observations, and to the necessity of having these repeated, and the whole series further extended, more especially the observations on the same medium at different temperatures. List of Tables presented by the author in illustration of the paper. TABLE I. Elements of Calculation. » II. Internal wave-lengths calculated from the observed Indices of Re- fraction. a III. Internal wave-lengths freed from the Extrusions. i” IV. The Extrusions. ” V. Logarithms of the wave-lengths of the fixed lines for each exponent from 1 to 3°5. ry VI. Indices of Refraction calculated from the Exponential Law. J VII. Observed Indices of Refraction. » WIII. Differences between observed Indices and those calculated by the Exponential Law. A: IX. Differences between observed Indices and those calculated by the law of M. Cauchy, with comparison of results. On the Law of the Wave-lengths corresponding to certain points in the Solar Spectrum. By Munco Poynton, F.R.S.E. This paper commences by tracing, to their basis, the numbers given by Sir Isaac Newton to express the wave- lengths corresponding to the borders of the coloured spaces of the spectrum. There is first obtained, by geometrical construction, the primary series 1*2857, 1°1428, 1°0714, 0°9643, 0°8571, 0°7714, 0°7232, 0°6429, the length of the mean wave being=1. Of these numbers the cube roots of the squares are taken, giving the series 1°1824, 1:0931, 10470, 0°9761, 0°9023, 0°8411, 0°8057, 0°7449. The length of the mean wave being experimentally ascertained to be 000002247 decimal parts of an English inch, the Newtonian wave-lengths are rata by multiplying the second of the above series by this quantity. They stand thus : 0°00002657 \ Red 0°00002456 | Orange | 0°00002353 | Yellow 0°00002193 | This is the estimate usually given of Green these wave-lengths, in the English 0°00002028 works on Optics. Blue 0°00001890 Indigo 0°00001812 Violet 0:00001674 / The two series given by Fraunhofer to express the wave-length corresponding to his seven principal fixed lines, are then stated in decimal parts of a French inch, as under :— I. B 0-00002541, C 000002425, D 000002175, E 0'00001943, F 0:00001789, G 0°00001585, H 0°00001451 oe 254 2422 2175 945 1794 1557 1464 +3 —2 —5 —2 —13 It is mentioned that the only approach to a law regulating these numbers, liftherta ascertained, is an approximation, in tie second series, to the relation : TRANSACTIONS OF THE SECTIONS. 21 1 -4() +0) (7) a1 (3 ‘ a) : It is then shown that the following relations subsist, with sufficient accuracy to admit of their being fairly assumed : viz. B’>=D* and B’ D=E'',—the E being that of the first series. Another advantage, presented by the first series, is then pointed out. The whole of the wave-lengths being formed into an equicentral series of ‘ BCDBC,DEEE. : 5 th 2 aye LY 7 h é ivi fractions, thus POPEREPFOH in which each greater is divided by each less; and these being arranged in the order of their magnitude, the following relations are traced: viz., B_C CB » BLE , B,C — =—-+0:22', ==—+0°22’, -=—+0'22, and —-++-—=3. ae a ee RE The series based on these relations stands thus : & Logs. Numbers. Differences. Fy 02436268 1°752374 C G 0°1847346 1°530152 0°222222’ E H 0°1270422 1°339807 0°190345 B 0°222229' F 071165846 1°307930 0°031877 F, 0-0960845 1°247626 0°060304 F 0-0886501 1°226451 0°021175 7 0:0848012 1°215630 0°010821 } 0°222222’ D EF 0°0490882 1°119665 0°095965 E = 0°0357130 1:085708 0°033957 ) 0°666666' by The differences between this series and the corresponding series deduced from the observed values, are shown to be so trifling that they may be fairly attributed to errors of observation. The wave-lengths, as calculated from this series, are then compared with the observed wave-lengths, as in the following Table :— Calculated. Observed. Differences. B 2540844 2541000 — 000156 C 2423694 2425000 — 001306 D 2175112 2175000 -+0000112 E 1942645 1943000 — 0000355 F 1789289 1789000 -+0000289 G 1583957 1585000 — 0001043 H 1449944 1451000 — 0001056 The differences here presented being smaller than the least of the differences between the corresponding members of the two observed series, the relations on which the calculated values are based are submitted as being in the highest degree probable. These relations present the advantage of rendering the whole of the wave- lengths deducible from that of either B or D. The following Table exhibits the relative wave-lengths, referred to that of B as unity :-— 22 REPORT—1859, Logarithms. Numbers. C 1°9794999 0'9538934 D 19325036 0°8560588 E 1°8834154 0°7645667 F 1°8477024 0°7042103 G 1°7947653 0°6233979 H 1°7563732 0°5706545 Mean wave M 1°9701116 0°9334940 It is next pointed out that the Newtonian wave-lengths corresponding to the lines of junction of the colours, are not reconcilable with the wave-lengths corre- sponding to the fixed lines of Fraunhofer, and that this diserepancy arises from the former having been deduced from an impure spectrum. It is shown, however, that if the primary series on which Newton’s. numbers are based be assumed without subjecting it to the process of taking the cube roots of the squares, and if it be mul- tiplied by the mean wave-length in decimal parts of a French inch, it will present a series agreeing better with Fraunhofer’s wave-lengths. The result is exhibited in the following Table, omitting the prefixed ciphers :— Borders of Colours, Fixed Lines. 27107 B 2540844 Red C 2423694 24094 Orange Mean wave M 2371900 22588 Yellow D 2175112 20330 Green E 1942645 18070 Blue F 1789289 16264 Indigo G 1583957 15247 Violet H 1449944 13554 This series makes the interval between the extreme violet and the extreme red as 1 to 2, corresponding to the musical octave. It is in conclusion suggested that fresh observations should be made, under the sanction of the British Association, on the wave-lengths corresponding to the bor- ders of the coloured spaces in the diffracted spectrum, to ascertain if they be accu- rately represented by the above series; so that the existing error, in regard to the estimated values of those wave-lengths, may no longer be perpetuated. On the Production of Colour and the Theory of Light. By Joun Sirs, M.A., of Perth Academy, Perth. The author had come to the belief, by means of experiments, that colour is pro- duced by alternate light and shade in various proportions. To prove this, he caused a white ray to revolve at various speeds on a black surface. His first experiment was to move a slip of white card-board over a black surface. By this motion he obtained a distinct blue; afterwards, in different weather, the same thing produced a purple. He then made a dise with five concentric rings. One ring was painted one-third black, the rest of the ring being white; the next ring was two-thirds black and one- third white; the next was three-fourths black and one-fourth white, and the fifth half black and half white. This disc, when made to revolve, became completely coloured ; there were no more blacks or whites visible, but five rings of different colours. Ona bright day with white clouds in the sky, the Ist ring was of a light green: much yellow. 2nd ring purple : very blue. 3rd ring nearly as first. TRANSACTIONS OF THE SECTIONS. 23 4th ring purple, darker than the 2nd. 5th ring pink. By means of excentric motions a great variety ot colours were obtained ; amongst others, a pure red and various shades of purple, pink, yellow, and blue. ‘The number of discs tried were very great, each disc having on it a different proportion of black and white. The author produced the same results by cutting out spaces in the white card, and causing it to revolve on a black surface. He produced also similar phenomena by causing these figures to revolve when held perpendicularly, and to take the appearance of coloured solids. He also caused these colours to be reflected on a white surface from the revolving disc. These experiments, and the views drawn from them, were used for the purpose of giving a theory of the prism, to be published in detail. It was by such processes that the author was led to believe that he had demonstrated that colour is produced by a mixture of light and shadow at various intervals ; and at last he was satisfied that the experiments were original, and not explicable by the present recognized laws. He concluded in these words nearly :—Remarkable as these experiments are, they are not more remarkable than the results they lead to, They prove the homogeneity of the ether. They prove the undulatory hypothesis, but oppose the uudulatory theory. They show the necessity of introducing a negative element into the theory of colour, or that colour is the effect of two coordinate sensations—a positive and a negative. They enable us to dispense with the different refrangibilities of the rays of light, taught by Newton. They remove the necessity for the supposition of different lengths of waves or of a disposition in matter to produce waves of different lengths. “alee help to explain many of the phenomena of what is called the polarization of light. They give a new explanation of prismatic refraction, and explain in a plain and simple manner many very interesting natural phenomena. Startling, he said, as these conclusions are, to those who are conversant with the subject of light, he thought he was perfectly warranted in drawing them from his experiments. On Radiant Heat. By B. Stewart, M.A. In addition to the facts communicated at the last Meeting, the author mentioned that he had since examined the nature of the heat emitted by heated rock-salt, and found that it possessed yery great wave-length. He had also shown that table-salt, pounded saltpetre, and pounded sulphate of potassa were white for heat; while pounded sugar, pounded alum, and pounded citric acid were black. The inference is that, could saltpetre or sulphate of potassa be obtained in crystals large enough, they would be diathermanous like rock-salt. He had also, in endeavouring to ascertain the law of particle radiation, asked him- self the question, What would be the consequence if the ultimate particles of dif- ferent bodies radiated the same quality of heat at the same temperatures? and he had calculated that were there a group of bodies possessing this common property, viz. having particles which radiate the same quality of heat at the same temperature, it would follow that if we were to take slices of such bodies of thicknesses such that they all permitted to pass the same proportion of heat of any one kind, then they would also all pass the same proportion of heat of any other kind. There are some indications that rock-crystal and glass crystal form one such group, and that citric acid and tartrate of potash and soda form another. On recent Theories and Experiments on Ice at its Melting-point. By Professor J. Toomson, M.A The object of this paper was to discuss briefly the bearings of some of the leading theories of the plasticity and other properties of ice, at or near its melting-point, on speculations on the same subject advanced by the author*; and especially to offer ‘* Proceedings of the Royal Society, May 1857 : also British Association Proceedings, Dublin Meeting, 1857. ~ : ‘ . ’ 24 REPORT—1859. an explanation of an experiment by Prof. James D. Forbes which had been advanced as in opposition to the author’s theory. He referred at the outset to the fact pointed out by Mr. Faraday in 1850 *, that two pieces of moist ice, when placed together in contact, will unite together, even when the surrounding temperature is such as to keep them in a thawing state. Mr. Faraday had attributed this phenomenon to a property which he supposed ice to possess, of tending to solidify water in contact with it, and of tending more strongly to solidify a film or a particle of water when the water has ice in contact with it on both sides, than when it has ice on only one side. Dr. Tyndall had subsequently adopted this fact as the basis of a theory by which he proposed to explain the viscidity or plasticity of ice, or its capability of under- going change of form, which had previously been known to be the property in gla- ciers in virtue of which their motion down their valleys is produced by gravitation. Designating Mr. Faraday’s fact under the term ‘‘regelation,” Dr. Tyndall, in the theory referred to, described the capability of glacier ice to undergo changes of form, as being not true viscosity, but as being the result of vast numbers of successively occurring minute fractures, changes of position of the fractured parts, and regela- tions of those parts in their new positions. The terms fracture and regelation had then come to be the brief expression of Dr. Tyndall’s idea of the plasticity of ice. The author, Professor James Thomson, considered, on the contrary, that if, in a material having no inherent property of plasticity independent of fracture, any steady force applied (such as the force of gravity acting on a glacier) be sufficient to cause fracture, the substance must go down suddenly until a position of repose is attained, and that the addition of a principle of reunion (such as ‘‘ regelation’’) cannot have a tendency to reiterate the fractures after such position of repose has been attained. His own theory, he stated, might be sketched in outline as follows :—If to a mass of ice at its melting-point, pressures tending to change its form be applied, there will be a continual succession of pressures applied to particular parts—liquefaction occurring in those parts through the lowering of the melting-point by pressure— evolution of the cold by which the so melted portions had been held in the frozen state—dispersion of the water so produced in such directions as will afford relief to its pressure—and recongelation, by the cold previously evolved, of the water on its being relieved from this pressure: and the cycle of operations will then begin again; for the parts recongealed must in their turn, through the yielding of other parts, receive pressures from the applied forces, thereby to be liquefied, and then to go through successive processes as before. He thus considered that the plasticity consists not of fracture and regelation, but essentially of melting by pressure and recongelation on relief from pressure. Professor James D. Forbest had adopted the view, that the dissolution of ice is a gradual, not a sudden process, and so far resembles the tardy liquefaction of fatty bodies, or of the metals which in melting pass through intermediate stages of soft- ness or viscosity. He thought that ice must be essentially colder than water in contact with it; and that, between the ice and the water, there is a film having its temperature varying from side to side, which may be called plastic ice, or viscid water; and that through this film heat must be constantly passing from the water to the ice, and the ice must be wasting away, though the water be what is called ice-" cold. Professor Forbes had stated afterwards, as a modification of this supposition, that if a small quantity of water be enclosed in a cavity in ice, it will undergo a gra- dual “‘regelation,’’ or that the ice will in this case be increased instead of wasted. In reference to this, Professor J. Thomson put forward the case of a medium quan- tity of water, in contact with a medium quantity of ice, without addition or abstrac- tion of heat; and stated that, were the idea of Professor Forbes on this subject cor- rect, the result in this case ought to be that the water and ice should ultimately pass into the state of uniform viscidity ; for Professor Forbes’s own words distinctly deny the permanence of the water and ice in contact in their two separate states, as he says, “ bodies of different temperatures cannot continue so without interaction. The water must give off heat to the ice, but it spends it in an insignificant thaw at the surface.”’ Thus then it would follow from the admission of Professor Forbes’s views, * See Faraday’s Researches in Chemistry and Physics, 1859.- + See Forbes ‘On the Recent Progress and Present Aspect of the Theory of Glaciers,’ forming the introduction to a volume of Occasional Papers on the Theory of Glaciers, 1859, TRANSACTIONS OF THE SECTIONS. 25 that viscid water could be produced in any large quantities desired, like as it is sup- posed to be produced in small quantities in the hypothetical thin film at the surface of hard ice—an inference which is plainly contrary to all experience, as no person has ever, by any peculiar application of heat to, or withdrawal of heat from, a quan- tity of water, rendered it visibly and tangibly viscid, so that it could be poured in a thick state like honey. We even know that water may be cooled much below the ordinary freezing-point, and yet remain fluid. Professor Forbes, however, although, in his recent writings, maintaining the views just alluded to, had not rejected the author’s theory as altogether unfounded. He had rather admitted that it points out some of the causes which may impart to a glacier a portion of its plasticity ; and also that it meets with verification to some extent in the moulding of ice subject to rapid alternations of pressure under the Bramah’s press. Mr. Faraday, in his recently published ‘ Researches in Chemistry and Physics,’ had adhered to his original mode of accounting for the phenomenon he had observed, and had developed farther the explanation of his ideas on the subject, and adduced examples of the action of numerous other substances in passing from the liquid to the solid, or from the solid to the liquid state, and also in passing from the liquid to the gaseous state. Professor J. Thornson, however, considered that the general bearing of all the phenomena adduced, is not to sustain the view of Mr. Faraday, but to show that the particles of a substance, when existing all in one state only, and in continuous contact with one another, or in contact only under special cir- cumstances with other substances, experience a difficulty of making a beginning of their change of state, whether from liquid to solid, or from liquid to gaseous, or pro- bably also from solid to liquid. He did not admit that anything had been adduced showing a like difficulty as to their undergoing a change of state when the substance is present in the two states already, or when a beginning of the change has already been made. He believed that when water and ice are present together, their free- ‘dom to change their state on the slightest addition or abstraction of heat is perfect. He therefore could not admit the validity of Mr. Faraday’s mode of accounting for the phenomena of so called ‘‘ regelation.”’ Thus the fact of ‘‘ regelation,’’ which Professor Tyndall had taken as the basis of his theory for explaining the plasticity of ice, did, in the author’s opinion, as much require explanation as the plasticity of ice which it was applied to explain. The two observed phenomena, namely, the tendency of two separate pieces of ice to unite when placed in contact, and the plasticity of ice, are, he believed, cognate re- sults of a common cause, and are explained by the theory he had himself offered. The experiment by Professor Forbes adduced in opposition to the author’s theory was to the following effect :— Two slabs of ice, having their corresponding surfaces ground tolerably flat, on being suspended in an atmosphere a little above the freezing-point, upon a horizontal glass rod passing through two holes in the plates of ice, so that the plates may hang vertically, and in contact with one another, were found in a few hours to be united so as to adhere strongly together. This Professor Forbes had supposed would prove that mere contact without pressure is sufficient to produce the union of two pieces of moist ice. The author, on the contrary, explained the fact by the capillary forces of the film of interposed water as follows :—First, the film of water between the two slabs—being held up against gravity by the capillary tension, or contractile force of its free upper surface, and being distended besides, against the atmospheric press- ure, by the contractile force of its free surface round its whole perimeter—except for a very small space at bottom, from which water trickles away, or is on the point of trickling away—exists under a pressure which, though increasing from above down- wards, is everywhere, except at that little space at the bottom, less than atmospheric pressure. Hence the two slabs are urged towards one another by the excess of the external atmospheric pressure above the internal water pressure, and are thus pressed against one another at their places of contact by a force quite notable in amount. Secondly, the film of water existing, as it does, under less than atmospheric press- ure, has its freezing-point raised in virtue of the reduced pressure; and it would therefore freeze even at the temperature of the'surrounding ice, namely, the freezing- point for atmospheric pressure. Much more will it freeze in virtue of the cold 26 REPORT—1859. given out in the melting by pressure of the ice at the points of contact, where, from the first two causes named above, the two slabs are urged against one another. The freezing of ice to flannel, or to a worsted glove on a warm hand, was, in his opinion, to be attributed partly to capillary attraction acting iv similar ways to those just stated ; but he considered that, in many of the observed cases of this pheno- menon, there are also direct pressures from the hand, or from the weight of the ice, or from other like causes, which must be supposed to increase the rapidity of the moulding of the ice to the fibres of the wool. On Electrical “ Frequency.” By Professor W. Tuomson, LL.D., F.RS. Beccaria found that a conductor insulated in the open air becomes charged some- times with greater and sometimes with less rapidity, and he gave the name of “ fre- quency”’ to express the atmospheric quality on which the rapidity of charging de- pends. It might seem natural to attribute this quality to electrification of the air itself round the conductor or to electrified particles in the air impinging upon it; but the author gave reasons for believing that the observed effects are entirely due to particles flying away from the surface of the conductor, in consequence of the impact of non-electrified particles against it. He had shown in a previous communication that when no electricity of separation (or, as it is more generally called, “ frictional electricity,”’ or “contact electricity ’’) ‘is called into play, the tendency of particles continually flying off from a conductor is to destroy all electrification at the part of its surface from which they break away. Hence a conductor insulated in the open air, and exposed to mist or rain, with wind, will tend rapidly to the same electric potential as that of the air, beside that part of its surface from which there is the most frequent dropping, or flying away, of aqueous particles. The rapid charging indicated by the electrometer under cover, after putting it for an instant in connexion with the earth, is therefore, in reality, due to a rapid discharging of the exposed parts of the conductor. The author had been led to these views by remarking the extreme rapidity with which an electrometer, connected by a fine wire with a con- ductor insulated above the roof of his temporary electric observatory in the island of Arran, became charged, reaching its full indication in a few seconds, and sometimes in a fraction of a second, after being touched by the hand, during a gale of wind and rain. The conductor, a vertical cylinder about 10 inches long and 4 inches diameter, with its upper end flat and corner slightly rounded off, stood only 8 feet above the roof, or, in all, 20 feet above the ground, and was nearly surrounded by buildings rising to a higher level. Even with so moderate an exposure as this, sparks were frequently produced between an insulated and an uninsulated piece of metal, which may have been about ;/,th of an inch apart, within the electrometer, and more than once a continuous line of fire was observed in the instrument during nearly a minuté at a time, while rain was falling in torrents outside. Remarks on the Discharge of a Coiled Electric Cable. By Professor W. Tuomson, LL.D., F.RS. Mr. Jenkin had communicated to the author during last February, March, and April a number of experimental results regarding-currents through several different electric cables coiled in the factory of Messrs. R. 8. Newall and Co., at Birkenhead. Among these results were some in which a key connected with one end of a cable, of which the other end was kept connected with the earth, was removed from a battery by which a current had been kept flowing through the cable and instantly pressed to contact with one end of the coil of a tangent galvanometer, of which the other end was kept connected with the earth. The author remarked that the deflections. recorded in these experiments were in the contrary direction to that which the true discharge of the cable would give, and at his request Mr. Jenkin repeated the experiments, watching carefully for indications of reverse currents to those which had been previously noted, It was thus found that the first effect of pressing down the key was to give the galvanometer a deflection in the direction correspond- ing to the true discharged current, and that this was quickly followed by a reverse. deflection generally greater in degree, which latter deflection corresponded to a cur- rent in the same direction as that of the original flow through the cable. Professor. Thomson explained this second current, or false discharge, as it has since been some=- TRANSACTIONS OF THE SECTIONS. 27 times called, by attributing it to mutual electro-magnetic induction between different portions of the coil, and anticipated that no such reyersal could eyer be found in a submerged cable. ‘The effect of this induction is to produce in those parts of the coil first influenced by the motion of the key, a tendency for electricity to flow in the same direction as that of the decreasing current flowing on through the remoter parts of the coil. Thus, after the first violence of the back flow through the key and gal- vanometer, the remote parts of the cable begin, by their electro-magnetic induction on the near parts, to draw electricity back from the earth through the galvanometer into the cable again, and the current is once more in one and the same direction throughout the cable. The mathematical theory of this action, which is necessarily very complex, is reserved by the author for a more full communication, which he hopes before long to lay before the Royal Society. On the Necessity for incessant Recording, and for Simultaneous Observations in different Localities, to investigate Atmospheric Electricity. By Professor W. Tuomson, LL.D., F.RS. The necessity for incessantly recording the electric condition of the atmosphere was illustrated by reference to observations recently made by the author in the island of Arran, by which it appeared that even under a cloudless sky, without any sensible wind, the negative electrification of the surface of the earth, always found during serene weather, is constantly varying in degree. He had found it impossible, at any time, to leave the electrometer without losing remarkable features of the phenomenon. Beccaria, Professor of Natural Philosophy in the University of Turin a century ago, used to retire to Garzegna when his vacation commenced, and to make incessant observations on atmospheric electricity, night and day, sleeping in the room with his electrometer in a lofty position, from which he could watch the sky all round, limited by the Alpine range on one side and the great plain of Piedmont on the other. Unless relays of observers can be got to follow his example, and to take advantage of the more accurate instruments supplied by advanced electric science, a self-record- ing apparatus must be applied to provide the data required for obtaining knowledge in this most interesting field of nature. The author pointed out certain simple and easily-executed modifications of working electrometers, which were on the table before him, to render them self-recording. He also explained a new collecting ap- paratus for atmospheric electricity, consisting of an insulated vessel of water, dis- charging its contents in a fine stream from a pointed tube. This stream carries away electricity as long as any exists on its surface, where it breaks into drops, The immediate object of this arrangement is to maintain the whole insulated con- ductor, including the portion of the electrometer connected with it and the connect- ing wire, in the condition of no absolute charge; that is to say, with as much posi- tive electricity on one side of a neutral line as of negative on the other. Hence the position of the discharging nozzle must be such, that the point where the stream breaks into drops is in what would be the neutral line of the conductor, if first per- fectly discharged under temporary cover, and then exposed in its permanent open position, in which it will become inductively electrified by the aérial electromotive force. If the insulation is maintained in perfection, the dropping will not be called on for any electrical effect, and sudden or slow atmospheric changes will all instan- taneously and perfectly induce their corresponding variations in the conductor, and give their appropriate indications to the electrometer. The necessary imperfection of the actual insulation, which tends to bring the neutral line downwards or inwards, or the contrary effects of aérial convection, which, when the insulation is good, gene- rally preponderate, and which in some conditions of the atmosphere, especially during heavy wind and rain, are often very large, are corrected by the tendency of the dropping to maintain the neutral line in the one definite position. The objects to be attained by simultaneous observations in different localities alluded to were,—1. to fix the constant for any observatory, by which its observations are reduced to absolute mea- sure of electromotive force per foot of air; 2. to investigate the distribution of electricity in the air itself (whether on visible clouds or in clear air) by a species of electrical trigonometry, of which the general principles were slightly indicated. A portable electrometer, adapted for balloon and mountain observations, with a burn- 28 RBPORT—1859. ing match, regulated by a spring so as to give a cone of fire in the open air, ina definite position with reference to the instrument, was exhibited. It is easily carried, with or without the aid of a shoulder-strap, and can be used by the observer stand- ing up, and simply holding the entire apparatus in his hands, without a stand or rest of any kind. Its indications distinguish positive from negative, and are reducible to absolute measure on the spot. The author gave the result of a determination which he had made, with the assistance of Mr. Joule, on the Links, a piece of level ground near the sea, beside the city of Aberdeen, about 8 a.m. on the preceding day (September 14), under a cloudless sky, and with a light north-west wind blowing, with the insulating stand of the collecting part of the apparatus buried in the ground, and the electrometer removed to a distance of 5 or 6 yards and connected by a fine wire with the collecting conductor. The height of the match was 3 feet above the ground, and the observer at the electrometer lay on the ground to render the electrical influence of his own body on the match insensible. The result showed a difference of potentials between the earth (negative) and the air (positive) at the match equal to that of 115 elements of Daniel’s battery, and, therefore, at that time and place, the aérial electromotive force per foot amounted to that of thirty-eight Daniel’s cells. On the Cause of Magnetism. By G. V. Tower. On Changes of Deviation of the Compass on Board Iron Ships by “ heeling,” with Experiments on Board the ‘ City of Baltimore, ‘Aphrodite,’ < Simla,’ and‘ Slieve Donard’ By Joun T. Towson. The author explained the manner in which the Compass Committee was first formed, in accordance with the advice of the Section, and stated that two reports had been drawn up, which, with the advice of the Astronomer Royal, had been printed and “presented to both Houses of Parliament by command of Her Ma- jesty.” He thanked the Astronomer Royal for his valuable advice and support. There were matters of consideration which the Compass Committee deemed incom- plete: the one was the change which took place in iron ships in proceeding to the opposite hemisphere ; the other, the change that was produced by what is technically denominated ‘heeling,’ that is, when the deck of a vessel leaned over, through the action of the wind or otherwise: if, when looking towards the bow, it slanted down- wards to the right, it was said to heel starboard ; if to the left, to heel port. The first question was undertaken by the late respected Rev. Dr. Scoresby, who proceeded to Australia in the ‘ Royal Charter,’ and whose exertions in the pursuit of this branch of the inquiry shortened a most valuable life. The second question was the subject of his present report. Having described the principles on which his graphic illustration was constructed, the author pointed ont the unexpected amount of deviation which this source of disturbance (heeling) brought about, amounting in most instances, when the ship’s head was in the position to produce the maximum effect, to two or three points in the standard compass, and to a greater amount so far as the steering com- pass is concerned. He remarked on several particulars connected with this investi- gation. Generally the north end of the compass was drawn to the upper side of the ship—the case with seven out of nine compasses on board the ‘ City of Baltimore ;’ but in the two steering compasses the needles were drawn in a contrary direction. He explained the theory on which this disturbance arose, partly from subpolar mag- netism below the compass, and partly from the disturbance of the inductive magnetism of the ships. In such ships as those under consideration, the following empirical rule held good with respect to compasses favourably placed. When the vertical force, as determined either by vibration experiments or torsion on board the ship, maintained the ratio, as compared with the vertical force on shore, of nine to fourteen, little or no effect was produced by heeling in the same hemisphere and latitude. And in the case of the ‘Simla’ this plan of predicting the amount of error was adopted: a moveable upright magnet was applied so as to produce the before-named vertical force, when it was found, “with magnet in,” no error was produced, although “ with magnet out” it amounted to 24° from changing a heel of 10° starboard to 10° port. There appeared to be another remarkable result, He believed that when a ship was TRANSACTIONS OF THE SECTIONS. 29 built with her head south-east or south-west, little if any effect would be produced by heeling. When examining the magnetic condition of the ‘ Slieve Donard,’ they were surprised to find that the vertical was very nearly that which would give no effect from heeling. Their able stipendiary Secretary (to whom is due the credit of drawing up the two Reports already published) immediately suggested that her head could not have been east when building, which we had taken for granted; and on inquiry we found that, on account of her great length, she had been built diagonally, with her head south-east nearly. Although he believed that for practical purposes sufficient inform- ation had been obtained, yet there were anomalies in their observations that rendered the theories deduced unsatisfactory. This he believed arose from the rapidity with which they were obliged to carry on their experiments, on account of the passing in and out of ships through the docks, from which cause the inductive influence of the earth had not sufficient time to complete its effect. It had been proposed to request the aid of the Admiralty in allowing the Committee to experiment on one of Her Majesty's iron ships, in some convenient place, for an unlimited time. On the Iris seen on the surface of Water. By J.J. Waker, A.M. This iris, in shape a more or less obtuse hyperbola, may be seen occasionally, in addition to the common rainbow, when a sheet of calm water lies between the spec- tator and the rain-cloud. It is formed by pencils of variously-tinted rays, which, after emerging from rain-drops, undergo reflexion at the surface of the water; and was first described and mathematically discussed by the author in the Philoso- phical Magazine for June 1853. The object of the present communication was to describe the phenomenon by the aid of an illustrative sketch; to point out the relation in which it stood to the se- condary rainbow observed by Halley, in which the rays had undergone reflexion at the surface of water before entering rain-drops ; and to suggest the correct mode of de- lineating it in works of art. ASTRONOMY. On the Present State and History of the Question respecting the Acceleration of the Moon’s Motion. By G. B. Airy, M.A., D.C.L., F.RS., Astro- nomer Royal. It had been known, from the time of Newton, that the motions of the moon are disturbed by the attraction of the sun, and that a great part of the effect is of the following kind, viz. that when the moon is between the sun and the earth, the sun attracts the moon away from the earth ; and when the earth is between the sun and the moon, the sun attracts the earth away from the moon; and thus, in both cases, it tends to separate the earth and the moon, or diminishes the attraction of the moon to the earth. There are sometimes effects of an opposite character; but, on the whole, the first described is predominant. If this diminution were always the same in amount, the periodic time of the moon passing round the earth would be the same. But it was found in the last century, by Halley and Dunthorne, that the periodic time is not always the same. In order to reconcile the eclipses of the moon recorded by Ptolemy with modern observations of the moon, it was necessary to suppose that in every successive century the moon moves a little quicker than in the preceding century, in a degree which is nearly represented by supposing that at each successive lunation the moon approaches nearer to the earth by one inch. The principal cause of this was discovered by Laplace. First, it had been shown by him and by others, that the attractions of the other planets on the sun and on the earth’ do not alter the longer axis of the orbit which the earth describes round the sun, and do not alter the length of the year ; but they diminish slowly but continually through many thousands of years the degree of ellipticity of the earth’s orbit. Now, when the earth is nearest to the sun, the decrement of attraction of the moon to the earth (mentioned above) is greatest; and when the earth is furthest from the sun, that decrement is least. It had been supposed that the fluctuations of magnitude exactly 30 : REPORT—1859. balance. But Laplace showed that they do not: he showed that the increased amount of decrement (when the earth is nearest the sun) overbalances the diminished amount (when the earth is furthest from the sun); and, therefore, that the less excentric is the earth’s orbit, the less does the increased amount of decrement at one part overbalance the diminished amount at another part, and the less is the total amount of the sun’s disturbing force. And, as the sun’s disturbing force diminishes the moon’s attraction to the earth, that attraction is less and Jess impaired every century, or becomes practically stronger; every century the moon is pulled into a rather smaller orbit, and revolves in a rather shorter period. On computing the effect from this cause, it was found to agree well with the effect which Halley and Dunthorne had discovered in observations. The lunar tables thus amended (and with other, but minor improvements) were applied to the computation of other ancient eclipses which require far greater nicety than Ptolemy’s Junar eclipses, namely, total eclipses of the sun. The most remarkable of these were the eclipse of Thales (which occurred at a battle), that at Larissa or Nimrad (which led to the capture of that city by the Persians from the Medes), and that of Agathocles (upon a fleet at sea). They are all of great importance in settling the chronology. Dates were thus found for these several eclipses, which are most satisfactory. About this time Mr. Adams announced his discovery, that a part of the sun’s disturbing force had been omitted by Laplace. The sun pulls the moon in the direction in which she is going (so as to accelerate her) in some parts of her orbit, and in the opposite direction (so as to retard her) in other parts. Juaplace and others supposed that those accelerations and retardations exactly balance. Mr, Adams gave reason for supposing that they do not balance. In this he was subsequently supported by M. Delaunay, a very eminent French mathematician, who, making his calculations ina different way, arrived at the very same figures. But he is opposed by Baron Plana, by the Count de Pontécoulant, and by Prof. Hansen, who all maintain that Laplace’s investigations are sensibly correct. And in this state the controversy stands at present*. It is to be remarked, that observations can here give no assistance. The question is purely whether certain algebraical investigations are right or wrong. And it shows that what is commonly called ‘‘ mathematical evidence’”’ is not so certain as many persons imagine; and that it ultimately depends on moral evidence. The effect of Mr. Adams’s alteration is to diminish Laplace’s change of the periodic time by more than one-third part. The computations of the ancient eclipses are very sensibly affected by this. At present we can hardly say how much they are affected: possibly those of Larissa and Agathocles would not be very much disturbed ; but it seems possible that the computed eclipse of Thales might be thrown so near to sunset as to be inapplicable to elucidation of the historic account. This is the most perplexing eclipse, because it does not appear that any other eclipse can possibly apply to the same history. The interest of this subject, it thus appears, is not con- fined to technical astronomy, but extends to other matters of very wide range. And the general question of the theory of the moon’s acceleration may properly be indicated as the most important of the subjects of scientific controversy at the present time. On the Mid-day Illumination of the Lunar Craters Geminus, Burckhardt, and Bernoulli. By W. R. Birt, F.R.A,S. The object of the present communication is to lay before the British Association for the Advancement of Science a few of the features that characterize the lunar sur- face in the neighbourhood of the craters, Burckhardt, Bernoulli, and Geminus, or more particularly on the area between the angular points: Burckhardt, Bernoulli, a small but bright crater on the southern margin of Messala (B), and a crater on an elevated ridge (a*) under the mid-day illumination. In the first report of the Committee appointed at Belfast to report on the physical character of the moon’s surface, the mid-day illumination is alluded to as “‘ making apparent the unequal reflective powers and different colours which characterize the different lunar regions, and the systems of brilliant stripes which are connected with certain lunar forms.” * See also Mr. Main’s elaborate statement in the Monthly Notices of the Royal Astrono- mical Society. bel : ase TRANSACTIONS OF THE SECTIONS. 31 The drawing accompanying this communication exhibits such reflective powers and different shades of tint, as well as certain remarkable phenomena connected therewith, which appear to be entirely unconnected with hypsometric relations, and manifest only the ground markings of this part of the lunar surface. It (the draw- ing) has resulted from the personal observations of the author, in accordance with the recommendations of the above-named Committee, and is perfectly unconnected with any previous delineations of this part of the moon’s surface, further than the relative positions of the three principal craters, which have been taken from Beer and Madler’s large map, the observations having been made with one of the Sheepshank’s telescopes, the property of the Royal Astronomical Society, each consisting of an original sketch executed at the time of observation. They extend from April to July of the present year. The features delineated may be seen during the period of the lunation that elapses between ten and fourteen days of the moon’s age. In the following description each feature will be separately noticed, preceded by a Roman numeral, References :—Names and Roman characters to Beer and Madler’s map, Arabic numerals to features that appear to be new to the author, or, in other words, that he has not met with a description of. I. Burckhardt.—The appearance usually presented by this crater under this illumi- nation is that of an ellipse, the northern and southern margins being more strongly illuminated than the eastern or western, which evidently results from the incidence of the solar light. The crater isin reality (as determined from hypsometrical inequal- ities brought out by morning and evening shadows) one that is superposed on an older depression, the extremities of the older crater being well marked in the evening illumination. No part of the ancient one is seen between ten and fourteen days of the moon’s age, only the brighter rim of the modern, with a central mark somewhat more luminous than the floor. Il. (c) A somewhat intensely bright circular spot near the south-western margin of Geminus, It is a small crater very apparent in the morning illumination, but almost disappearing under the evening. Ill. (1) A dark mark near (c). It is not in the nature of a shadow, the incident light being opposed to that view. The author is disposed to regard it as a portion of the surface reflecting much less light than the crater. IV. (2) A bright narrow stripe emanating from (c) directed towards Burckhardt : this stripe may be slightly too wide in the drawing. Note.—There is an extremely brilliant crater in Cleomedes (A) in Beer and Madler’s map, with a similar stripe towards Burckhardt. V. (3) A bright stripe from (2) towards the dark ribbon (15) : this stripe extends considerably beyond the dark ribbon towards the east. _ VI. (4) Anextensive space of nearly the same uniform tint; it is rather darker be- tween Burckhardt and Bernoulli, and covers the southern part of GEMINUS. VI. Bernoulli.—The floor of this crater under the mid-day illumination is dark, with a light rim seen under the same circumstances as the rim of Burckhardt, VIII. (a) A small but well-marked crater between Bernoulli and Messala, IX. (5) A curved bright stripe somewhat hooked, extending from (a) to Ber- noulli. X. (6) A dark space somewhat lighter than the floor of Bernoulli, extending between Bernoulli and Messala. It is not of the form shown in the drawing, a small i Pal extending further west. I. (B) A crater on the margin of Messala; it is not distinatly discernible under this illumination. XI. (7) A bright space covering the northern part of Geminus, extending and converging to (B), the crater in the southern margin of Messala. XIII. (8) A bright narrow stripe crossing Geminus ; it passes through the dark ribbon, as may be seen with a powerful instrument, and extends towards the north of Cleomedes across the narrow stripe (3). XIV. (9) A bright narrow curved stripe, apparently the north-western margin of Geminvus. It is seen eastward of the dark ribbon, and extends towards the eastern extremity of the stripe (3). XV. (10) A dark space somewhat like a spur, apparently within and external to Guminus, and dividing the curved stripe on its margin. a Se REPORT—1859. XVI. (a*) A small crater which is situated upon the northern extremity of a ridge (not the ribbon 15), as manifested by the morning and evening illuminations. This ridge does not exhibit any reflective powers different from those of the surrounding land. XVII. (11) The outlines of an obliterated crater with its darker floor and some- what lighter rim than the space (12). No indications of any hypsometrical relations of this crater are met with morning and evening, so that it would appear to have been filled up. 1t is a somewhat difficult object to see, and requires good definition. XVIII. (12) A space of nearly the same uniformity of tint as (4) between Geminus (a*) and (B). It is rather darker towards the ribbon. ae ‘i \ Two small somewhat light spots ; they do not appear to be craters. XXI. (15) A dark ribbon-like band extending from Burckhardt to Geminus, skirting the eastern margin of Geminus and proceeding towards (a*). This dark ribbon is not in any way elevated above the general lunar surface, as no shadow is perceptible either in the morning or evening ; in fact it disappears entirely under theseilluminations. It isclearly a ‘ ground mark ”’ exhibiting differing degrees of intensity. Contemplating the drawing as it lies before us, we see at a glance that during the four days (moon's age 10 to 14) we are dealing in this part of the moon with markings of the surface only. This conclusion is particularly forced upon us by the remark- able phenomena presented by Grminus. The depth of this crater, as well as the elevation of its walls, are well brought out by light and shadow, especially in the fore- noon illumination, but as the day advances the crater-form is lost; in fact such is the metamorphosis the crater undergoes, that only a portion (the northern) is recog- nizable, and this more by the curved outline and narrow stripe across, than by any- thing else. Between the dark ribbon (15) and the dark space north of Bernoulli(6), including the dark-floored Bernoulli itself, a space of somewhat uniform breadth extends. This space, which is of alighter tint than either of the narrower stripes bounding it east and west, is crossed by a brighter space (7), which passing over Geminus, converges to the crater (B) in the southern margin of Messala. This brighter space is not peculiar to the locality between the two narrow darker fringes ; it extends considerably to the eastward of Geminus, passes near to a crater marked by Beer and Madler (A), and is connected with the system of brilliant stripes radia- ting from the brilliant crater Proclus. The narrow stripe (8), which is rather brighter, belongs to the same class as (2), (3), and (9), and may be seen crossing Geminus on the eighth day of the moon’s age, both northern and southern walls being apparent ; it consequently traverses alike elevation and hollow. It would appear (assuming for a moment that the bright space (7) existed anterior to the production of the crater, an assumption by the by for which there are no reasonable grounds) that that produc- tion had not in the least degree influenced the reflective powers of those parts of the surface on which the crater is situated. On the other hand, assuming that both brighter and darker tints resulted from some change after the crater was produced, it is difficult to see how the complete obliteration of the southern part should be effected at the same time that its elevated wall remains. That the wall is not materially interfered with, is evident from the fact that both wall and depression come out in strong relief with the evening shadows. It is very possible that the crater might have been produced when the entire area between the two dark fringes reflected light similarly, and that its southern wall with its step or terrace only presented phenomena of light and shade when the morning and evening incidences were such as to bring them out from hypsometrical inequality. The narrow stripe (8) across is evidently posterior in age to the crater itself, and may or may not be contemporaneous with the production of the lighter area con- verging to Messala; and from the distinct and well-marked manner in which the north-western rim is cut off at the junction of the lighter and darker areas, it would appear that this brighter rim is also of later origin. The bright crater (C) deserves a passing remark. Onconsulting Beer and Madler’s map, it will be seen that Burckhardt is situated nearly midway between it and the bright crater marked (A) in Cleomedes, from which a similar stripe extends to Burckhardt, A question here suggests itself. Is Burckhardt at a lower level than TRANSACTIONS OF THE SECTIONS. 33 either (C) or (A)? The author has not yet detected hypsometrical evidence of this : or has there been some tendency in the direction of Burckhardt to produce cracks and fissures from the two small craters N.W. and S.E, of it? Epoch ten to fourteen days of the moon’s age. Mid-day illumination of the lunar area between the angular points Burckhardt, Bernoulli ; B a crater on the southern margin of Messala and the crater a*. Relative positions, approximately, from Beer and Madler’s large map. Names and Roman characters refer to Beer and Madler’s large map. Arabic numerals to features observed by the author, described in the accompanying paper, - and not described elsewhere, so far as the author is aware. Drawn from sketches taken at interyals between April and July 1859. 1859. 3 34 REPORT—1859, On Sir Christopher Wren’s Cipher, containing Three Methods of finding the Longitude. By Sir Daviv Brewster, K.H., LL.D., F.R.S. Sir David said that at page 263, vol. ii. of his ‘ Life of Sir Isaac Newton,’ the following paragraphs would be found: —“ The bill which had been enacted for reward- ing the discovery of the longitude seems to have stimulated the inventive powers of Sir Christopher Wren, then in his eighty-third year. He communicated the results of his study to the Royal Society, as indicated by the following curious document which I found among the manuscripts of Newton :— / “« «Sir Christopher Wren’s cipher, describing three instruments proper for discover- ing the longitude at sea, delivered to the Society November 30, 1714, by Mr. Wren :— OZVCVAYINIXDNCVOC WEDCNMALNABECIRTEWNGRAMHHCCAW. ZEIYEINOIEBIVTXESCIOCPSDEDMNANHSEFPRPIWHDRAEHHXCIF, EZKAVEBIMOXRFCSLCEEDHWMGNNIVEOMREWWERRCSHEPCIP. Vera copia. Epm. Hairy.’ We presume that each of these paragraphs of letters is the description of a separate instrument. If it be true that every cipher can be deciphered, these mysterious paragraphs, which their author did not liveto expound, may disclose something interesting to science.” Sir David Brewster went on to say that soon after the publication of ‘The Life of Sir Isaac Newton,’ he had received a letter from Mr. Francis Williams, of Grange Court, Chigwell, suggesting very modestly that as the deciphering of the cipher, as published, was so simple, he supposed many persons had already done so ; but ifnot, he begged to say that the mystery could be solved by reading the letters backwards in each of the three paragraphs, omitting every third letter. He had, on the approach of the Meeting of the British Association, received permission from Mr. Williams to give an account to this Section of Mr. Williams’s method of solving the enigma. In his letter conveying the permission, which Sir David read, he suggests that “‘ Sir Christopher Wren’s object was to make it too mysterious to be of use to any one else. It is possible he may have wished to delay for a time the publication of his inventions, perhaps till he had improved his instruments, but was afraid that in the interval another would hit upon and publish the same discovery. He would send this cipher, then, to the Royal Society as a proof to be used at any future time.” Sir David had the following explanation then, in accordance with Mr. Williams’s suggestion, written upon the black board, the letters to be omitted being written in small characters to distinguish them, and backwards :— WAcCH hMArGNwETrICeBAnLAmNCdE WcOUcNDxINiVAvCUzO. —Wach magnetic balance wound in vacuo (one letter a misprint). The omitted letters similarly read are—CHR. WREN, MDCCXIV. FIcX HhEArDHwIPrPEeSHnANmDEdSPcOIcSExTUiBEiONiEYiEZ.—Fix head hippes handes poise tube on eye (one letter a misprint). Omitted letters make— CHR. WREN, MDCCXIIII. PIcPEhSCrREwWErMOeVInNGmW HdEEcLScFRxOMiBEvAKzE.—Pipe screwe moving wheels from beake. Omitted letters make—CHR. WREN, MDCCXIYV. The three last omitted z’s occurring in the first part of each cipher to show that that part must be taken Jast. On the Longitude. By Sir C. Grey. On the Inclination of the Planetary Orbits. By J. Pore Hennessy, M.P., F.G.S. The author stated that, on consulting a synoptic table of the planetary elements, some laws had been obtained for the other elements, but none hitherts for the in- clinations of the several orbits. This he conceived arose from the inclinations being set down in reference to the plane of the earth’s orbit; for he found that a very re- markable relation manifested itself when they were tabulated in reference to the plane of the Sun’s equator. The author had written on the board two tables: one, TRANSACTIONS OF THE SECTIONS. 35 the ordinary table, in reference to the Ecliptic; the other, that to which he wished to draw attention, having reference to the plane of the Sun’s equator. In the latter it was seen, as a general law, that the inclinations of the planetary orbits increased as the distances of the several planets from the sun increased. Thus, the inclina- tioh of the orbit of Mercury to the plane of the Sun’s equator was but 0° 19’ 51”, while that of Neptune was 9° 6’ 51”,—the only considerable deviation from regular progression being found, as might be expected, among the asteroids; of which if we take Victoria as a type, her inclination is no less than 15° 42’ 15”. The author considered that the fact that the orbits of the larger planets, Jupiter, Saturn, Uranus, and Neptune, are not more inclined, would seem to confirm a surmise of La Place, who, in his ‘ Exposition du Systeme du Monde,’ speculates on the order in which the planets were thrown off from the Sun, and supposes that Jupiter, Saturn, &c. were thus formed long before Mercury, Venus, the Earth, and Mars. If so, the oblate- ness of the Sun would, in its condition at that time, have tended more powerfully than in its subsequent or present state to keep the planets near the plane of its equator. The discovery of this law regulating the inclinations of the planetary orbits appeared to him another addition to the class of facts which establish the analogy between the Solar system and that of Jupiter and his satellites, it being well known to astronomers that the inclination of the orbits of the latter to the plane of Jupiter’s equator was a function of their distances and masses. On Chinese Astronomy. By J. B. Linpsay. The object of the present paper is to draw the attention of this Section to the fact, that much information may be derived from Chinese literature in order to perfect our astronomy. The ‘ Chun-tsiu,’ written by Confucius, contains an account of thirty-six eclipses (several of them total), and several comets, falling stars, and meteorites. The first eclipse here recorded was in the year before our era 719, the last was in B.c. 494, thus comprising 225 years. Confucius was born in B.c. 550, and died at the age of seventy-three in B.c. 477. In a book lately published I have given an extract of the thirty-six eclipses ; but the whole of the ‘ Chun-tsiu’ deserves to be translated and published. I have myself made a translation of the whole ver- batim, but should prefer seeing it published by another better acquainted with the Chinese. The ‘ Chun-tsiu’ is a short chronicle of events; but there is an extended commentary on it entitled the ‘Tso-chuen,’ by Tso-kiu-ming, who was a contem- porary and an intimate friend of Confucius. This work should, I think, be also translated, as it gives a detailed account of astronomical observations, and comes thirteen years further down than the work of Confucius. Another work, entitled the ‘ Kwo-yu,’ supposed to have been by the same author, contains an Appendix by another person, bringing down the history to B.c. 453. The succeeding history was principally written, and the celestial phenomena recorded, by Szi-ma-tsien, who lived a century before our era. His work is entitled ‘ Shi-ki,’ or Historic Memoirs. He was Imperial Historian, as was also his father; and his work is extremely _interesting, as giving an account not only of Chinese affairs, but also of the Scythians and Turks who were then on the north-west borders of China, The 123rd chapter, recording foreign events, has been translated into French by Brosset, and is found in the Journal Asiatique for 1828. This chapter comprises the history of forty-three years, or from’B,c. 140 to B.c. 97, shortly before the author’s death. Small portions of the ‘ Shi-ki’ have been translated into English, but the whole deserves to be so: A translation of the whole Chinese history and literature before our era would not be voluminous; but the ‘ Chun-tsiu,’ the ‘Tso-chuen,’ and the ‘Shi-ki’ should, I think, be translated first. Extended notes would be necessary to render the whole intelligible, and the Astronomer Royal might append notes on the various eclipses. The ancient Chinese classics are nine in number,—five of the first class, and four of the second. The five of the first class are the ‘ Shu-king,’ the ‘Shi-king,’ the «[-king,’ the ‘ Li-ki,’ and the ‘Chun-tsiu.? The ‘ Shu-king’ has been translated into French by Desguignes, ; the ‘ Shi-king ’ into Latin by Lacharme; the ‘ I-king ” into Latin by Regis, and others; the ‘ Li-ki’ into French by Callery ; but the ‘ Chun- tsiu’ has not yet been translated into any European language. The four books of the second class have been often translated into Latin and French. Their names are, the ‘Ta-hio,’ the ‘ Chung-yung,’ the ‘ Lun-yu,’ and ‘ Mang-tszi,’ or Mencius,— scarcely any of which have been translated into English. 3% 86 REPORT—1859. On an Improvement in the Heliometer. By Norman Pogson, Director of the Hartwell Observatory. The purpose of this communication is to suggest what I conceive to be a great addition to the power of any kind of micrometer used for measuring long distances on the double-image principle. It is therefore especially applicable to heliometers, and has indeed occurred to me chiefly from familiarity with the defects which have hitherto rendered this costly but magnificent instrument a comparative failure. It is well known to practical astronomers that the contact between two stars, however skilfully made, is a very unsatisfactory observation, even when the objects are pretty equal. But when one is a large bright star and the other a faint one, the difficulty and uncertainty amount to impossibility ; for the faint star is invariably obliterated on approaching within two or three seconds of its superior. The alternative is then to diminish the aperture of that half of the object-glass through which the brighter star is viewed; but here again arises another evil ; the disc is enlarged by diffraction, the value of the scale sensibly changed, and definition materially injured. Hence parallax determinations of first magnitude stars, such as Arcturus and a Lyra, cannot be satisfactorily made; but when the object is a double star, as, for instance, 61 Cygni or Castor, the comparison star can be brought between the components of the double star, and a most exquisitely perfect and comfortable measure obtained. Now, from having used the rock-crystal prism micrometer when residing at Oxford last year,—then kindly lent me, together with a five-foot telescope of surpassing excel- lence, by Dr. Lee,—the idea occurred to me of introducing a prism, or achromatized wedge of rock-crystal, into the heliometer, so as to double the image of the brighter star. By this means the dubious contact would be dispensed with ; for the fainter object, by being brought midway between the two images of the bright star, would be precisely similar to the present easy observation of 61 Cygni previously referred to. The prism could be of sucha constant angle as to separate the two images to a convenient distance ; not too far, so as to render the estimation of distance difficult, but just wide enough to prevent the obliteration of a faint comparison star, before named as one of the evils to be avoided. The prism rather improves the appearance of a bright star than otherwise; and_as the images are doubled, of course half the light of each is lost, equivalent to a considerable reduction of the aperture, thus obviating the third objection alluded to at starting. Armed with this addition to its strength, and taking the precaution never to observe on bad nights, when the atmosphere will not permit the use of powers from three hundred upwards—for I hold it as an absurdity to attempt to investigate tenths of a second of are with any- thing less—the heliometer is doubtless yet destined to realize the highest expectations ever raised, as to its efficiency for grappling with that most minutely intricate and vastly important research, viz. the parallax of the fixed stars ! On three Variable Stars, R and S Urse Majoris, and U Geminorum, as observed consecutively for six years*. By Norman Pocson, Director of the Hartwell Observatory. (Communicated by Dr. LEE.) [With a Plate. ] The periodical variation in brilliancy of certain fixed stars has now been known to astronomers for more than two centuries. The fact of simple change, apart from periodicity, has been recognized and recorded for nearly two thousand years; and while every other celestial phenomenon has been explained and reduced to intelligible methods of calculation, based upon theories as incontrovertible as the events they foretell in future or account for in past times, these changes of light and colour remain enshrouded in mystery, and their prediction as purely empirical as was that of eclipses by the Chaldeans of old, aided by their renowned Saros, or eclipse-period of 223 lunations. It is not, however, for want of due thought and attention from the eminent astronomers of the past and present that such a reproach attaches to any branch of their science. Commencing with Fabricius, who first drew attention to the dis- * This paper was illustrated by large diagrams of the light curves of the above three vari- able stars, covering an area of. more than sixty square feet. The portions most especially referred to by the author have been reduced to a suitable scale, and are given in Plate I. TRANSACTIONS OF THE SECTIONS. 37 appearance of the now well-known variable Mira Ceti, and the Dutch Professor Holwarda, who discovered its periodicity, the list of observers of these objects includes most of the greatest names that have figured in astronomy :—Hevelius, Bulliald, Montanari, Cassini, Maraldi, G. and C. Kirch, Halley, Koch, Goodricke, and Pigott—all contributed largely by discovery or observation to our knowledge of the variable stars. Sir William Herschel’s first astronomical communications were upon the same subject, since most ably followed up by Sir John Herschel, the distinguished inheritor of his great name and lofty talents. Olbers paid great attention to the variable stars, as also Harding, Wurm, Westphal, Schwerd, and above all others, Professor Argelander, of Bonn. To him is due not merely the merit of arranging the labours of all that had preceded him, and more accurately investigating the elements of change of most of the old variables, as well as the discovery of several new ones, but that of training a band of young and able followers, who by their successive discoveries and patient researches have honoured both themselves and their great instructor. In England, besides the labours of Sir John Herschel, Mr. Hind has discovered no less than twenty-one new telescopic variable stars, two of which, S Cancri and U Geminorum, are especially remarkable. The writer of this paper has also contributed ten to the list, which now numbers more than eighty of these interesting objects. Mr. Baxendell of Manchester, Messrs Chacornac and Goldschmidt of Paris, as well as Drs. Winnecke, Schcenfeld, Luther, Auvers, Hoek, Oudemans, and Schmidt, are all devoting more or less of their time and attention to the same pursuit. Why then, it may be inquired, have not all these combined efforts proved as suc- cessful as they undoubtedly deserved to be, in arriving at more satisfactory results ? We can only regret the circumstance, and redouble our exertions to attain so important an object. Want of continuity is doubtless a most weighty objection to all pre- viously published series of observations, and one which the observers could not help: for unless a star be circumpolar, there must inevitably occur a break in the records of its changes during the time that it is in conjunction with the sun, and therefore not observable. It is not enough merely to watch a star through its successive maxima; every stage of its variation should be remarked, and an unbroken record thereof kept for years, or at least through ten or twelve complete periods. The detection of four remarkably regular variable stars, suitably placed in the circumpolar region, has enabled me to secure this desideratum, and to supply data not previously available. A brief summary of the principal features hitherto remarked in periodical stars, may be advantageously stated, before proceeding to the description of our illustrations. Some of them, from fine bright stars distinctly visible to the naked eye, fade away beyond the limits ofthe largest telescopes in use, and after remaining invisible a certain time suddenly regain their brilliancy. The increase in light is generally more rapid than the diminution, and about or after maximum such stars are frequently more or less red. Others, usually of short period and small variation, complete their changes in a few hours, and at all intermediate stages are of a constant magnitude. Most of the stars of this class are visible to the naked eye and pretty steady in their periods, which may be stated as between the limits, three and forty-six days ; while those of the former class, or vanishing stars, range from 97 to 650 days in the interval between two successive maxima. Jn one instance the period cannot be less than seventy-three years ; and it is even probable that some of the brilliant visitors, described as new or temporary stars in past ages, may be periodical, but returning only after the lapse of many centuries. The largest of our three diagrams represents the light curve, or graphic history, of the circumpolar variable star R Ursee Majoris, since 1853, the year of discovery of its variability. Eight maxima, dependent upon 138 observations, and seven minima, resting upon 122 observations, making in all 260 nights on which the star has been examined, are here presented to the view. The Time co-ordinates, marked along the top and bottom of the projection, are on a scale of ten days to an inch, The other co-ordinate—magnitude or light—is marked at each extremity of the dia- gram. ‘The upper limit, which, however, this star has never attained, is the 6th magnitude, or faintest visible to the unassisted sight. The lower limit is 133, or the faintest magnitude discernible with a telescope of 7 inches in aperture, The 38 REPORT—1859. observation of every night is represented by a black spot. Thus, on 1855, September 19, the magnitude of the star was recorded 6°6 ; on November 8, it had diminished to 8°8 ; and on 1856, March 7, when only just discernible, it was noted 13°5. It appears therefore, that if R Urse Majoris never becomes visible to the naked eye, on the other hand it never quite vanishes with an object-glass of 7 inches in aperture. A waved line, smoothly traced among these dots, so as to pass as nearly as possible through the mean of each three successive observations, is adopted as the curve which represents the variations of the star with the most probable exactitude. The general regularity and similarity of the different periods is strikingly evident, also the gradual descent of the curve corresponding to diminution of light, and its rapid ascent or brightening up before each maximum. The whole period being 302 days or ten months, the interval from maximum to minimum is 191 days, that from mivimum to maximum only 111 days. Closer inspection will bring to view some more interesting details. At the first observed maximum the star acquired only the 8th magnitude. At the next it became 0°6 of a magnitude brighter, or shone with half as much light again as on the first occasion, On the photometric scale adopted, which is an average of those employed by all the chief catalogue constructors who paid attention to the relative magnitudes of the fixed stars, and is in exact accordance with the notation of Professor Arge- lander, the highest authority on that point, one star is said to be a magnitude brighter than another, when it contains 21 times the actual light of the fainter star. ‘thus a 7th magnitude is 23 times as bright as an 8th. At the next three maxima, viz. 1854, November 22; 1855, September 15; and 1856, July 10, R Urse Majoris was within 0°1 of the 7th magnitude. But at the next maximum on 1857, May 15, it reached the 6°7 magnitude—the brightest on record; a veritable maximum maximo- rum! On the last two occasions, viz. 1858, March 16, and 1859, January 5, it did not exceed the 7°6 magnitude. Owing to the extreme faintness of this star at its minima, less weight can be assigned to their determination, but similar fluctuations are manifested, especially by the first four. After reducing the fifteen equations afforded by this curve, by the method of least squares, the resulting elements of variation are :—period, 301°91 days; epoch of minimum, 1858, September, 159 ; and that of maximum, 1859, January, 6°6 ; which represent the original observations with surprising accordance. The mean difference between an observed maximum and one computed from the elements is 2? days; the extreme difference 54 days. For the minima, these differences are—mean, 43; extreme, 8 days. Strong evidence this, in favour of the regular periodicity of the star, and the sufficiency, both of the observations and their treatment by this simple but effectual method of projection, when for two of the oldest known variables, o Ceti and x Cygni, the most refined formulz of calculation often disagree with observation to the extent of twenty-five and forty days respectively ! ; It must not be supposed that the observations here projected are mere estimations of the magnitude of the variable; nei- —— = —- ther are they photometric measures of the actual light emitted by the star. In either case, the changes inthe atmosphere or in the sensibility of the observer’s eye would materially affect the estimation, and the dots would stand out very un- satisfactorily from the interpolating light- curve. The method employed is as fol- lows :—A map of the neighbourhood of each variable is constructed, and a cer- tain number of stars selected, if possible | in the same telescopic field of view, as standards of reference. One of these maps, viz. that of the variable just de- | +70" scribed, is here given for the purpose of 4,7” *° *! %4 33 33 35 36 37 38 39 40 1 illustration. 10 Minutes of Right Ascension The comparison stars, nine in number, are lettered in order of brilliancy, and their adopted magnitudes, the means of careful estimations on twenty favourable nights, TRANSACTIONS OF THE SECTIONS. 39 are as marked on the map. The variable star is compared with these selected standards on each occasion. Thus, on 1855, December 18, my record made with the equatorial of the Radcliffe Observatory was—R, 0°8 of a magnitude less than comparison star d; 0°3 less than e; equal tof; 0°6 brighter than g; which differ- ences, applied to the adopted magnitudes of the references employed, yield the four values 10°6, 10°7, 10°4, 10°6. The mean of these, 10°6, is then the relative magni- tude of R Urs Majoris on that night, eliminating all the liabilities to error which could attend direct estimation. The eye is wonderfully acute, after a little practice, in detecting differences of brilliancy, second only to the ear in distinguishing small intervals of musical sound; and an inequality between two stars of only ‘5th of their light, considerably less than a tenth of a magnitude, is fairly appreciable. Three maxima, forming a portion of the light-curve of S Urs Majoris, another of the four circumpolar variables found at the Radcliffe Observatory, are projected ina precisely similar manner, and on the same scale as in the preceding example. The period and range of variation of this star are each considerably less than in the case of R Urse Majoris. Its changes are completed in 2224 days or about 7} months. The brilliancy at different maxima fluctuates between the 7°5 and 8°5 magnitudes. The minima also lie between the 11°8 and 12°8 magnitudes. The ‘times of increase and decrease are performed in 95 and 127 days respectively. The most singular feature exhibited by this star, is the different duration of greatest bright- ness at certain maxima. For instance, at the very flat-looking maximum which occurred on 1855, June 17, S Urse Majoris preserved the same intensity, viz. the 84 magnitude, for nearly two months. At the next maximum, 1856, February 11, the star acquired the 8°2 magnitude, but changed more in twenty days than pre- viously in nearly three times that interval. At the next return, 1856, September 14, it increased to the 7°7 magnitude, but scarcely remained a fortnight at greatest bril- liancy. The minimum also, on 1855, October 24, when of the 12°3 magnitude, compared with the next on 1856, January 14, is much sharper and shorter, as well as fainter in its actual light. Since May 1853, when its variability was first detected, the star has been examined on 270 nights, comprising eleven minima and ten maxima in unbroken succession. On looking at such a long flat vertex to a curve, as the first on the diagram of S Ursee Majoris, it may be asked how the exact day of maximum is deduced, when the star remained so little changed for two months? The small circular marks and the short line traced through them are the reply to this inquiry. Reading from the light curve the days on which the star was of equal brightness during increase and decrease, a mark is placed half-way, or at the mean of the two days. This is done for different stages of brightness,—in this instance when the star was of the 10°2, 9°8, 974, 9°0, and 8°6 magnitudes. A curve is then smoothly passed through these points, and the point defined by the intersection of the light-curve with this line is regarded as the day of maximum intensity. Any more refined process would be but labour lost. Projection has two great advantages over calculation, when applied to these observations ; it economizes time, and by the flagrant outstanding of any particular dot, immediately detects errors which might easily escape notice when intermingled in a column of figures, but which would not fail to vitiate our results if overlooked, in the deduction of the elements of variation. R Cygni, a star of 417 days period—discovered in August 1852, and since then continuously examined on 243 nights—is a third circumpolar variable, extremely steady in its changes. It descends from the 8th to below the 14th magnitude in 245 days, but returns to its next maximum in 168 days. It is quite invisible with a 7-inch object-glass for above three months. The fourth circumpolar variable, R Cassiopeiz, likewise increases rapidly, fading away very gradually ; the whole period extending over 435 days or more than 14 months, and ranging generally from the 6th to the 13th magnitude. At maximum this star emits a vivid red or almost a scarlet light. R Cygni and S Urse Majoris also show a fine deep red tinge. KR Urse Majoris, on the contrary, never appears red, nor indeed deviates from its ordinary yellowish-white colour at any part of its eriod. - In striking contrast to these, and indeed to most other variables, stands U Gemi- norum—a truly wonderful star, discovered by Mr. Hind in December 1855. Its 40 REPORT—1859. short period of 97 days was detected at the Radcliffe Observatory, at its very next return, in March 1856. The star is visible only for about ten or twelve days. To what an infinity of faintness it must diminish during its 85 days of invisibility is beyond all conception, and perfectly overwhelming to the imagination! Its appear- ances show a pretty regular periodicity ; but here again it is strangely anomalous, for it sometimes fails to return at all, as will shortly appear from the projection. The colour is invariably bluish white, and at some maxima its light is ever dancing and unsteady ; at others exactly the reverse, as pale and calm as a planet’s. Requesting attention to the diagram so freely striped with red* lines, the upper limit no longer represents the 6th but the 7°5 magnitude; the lowest line, the 15th—a trifle beyond the vanishing-point of the large reflector of Mr. Worthington, of Manchester ; which has been directed to it frequently, and to excellent purpose, by my friend Mr. Baxendell, of that city. At its discovery by Mr. Hind, on 1855, December 15, it was estimated of the Oth magnitude, and was announced in the 7imes as ‘a new planet at its stationary point, or a new variable star.” On December 18 it was a little fainter, though still visible, but disappeared before the end of the month. The black hyperbolic-looking curve, shaped agreeably to later re-appearances, but fitted in to Mr. flind’s dates, shows the probable nature of its changes at its first recognition. The red lines fol- lowing are records of invisibility, showing that the star was looked for but not seen, and therefore less than the magnitude indicated by the top of each such red line. Thus, on 1858, May 16, an unfavourable night at Manchester, stars of the 13°4 magnitude were just visible when U Geminorum was not. On 1856, January 12, a fine night, it was invisible to Mr. Hind with the South Villa equatorial, and there- fore less than 13°5 magnitude. On Jannary 27, when sought for at Oxford, with a small but excellent portable telescope, 2} inches in aperture, it was invisible, and under the 11th magnitude. As previously stated, its period was detected at its first return, at the Radcliffe Observatory, when three observations were obtained. It must have passed its maximum on 1856, March 23. It was seen of the 9°6 mag- nitude on the 26th; of the 10°2 magnitude on the 27th; of the 11th magnitude on the 29th, but had quite disappeared on April 2, and was then less than the 13°5 magnitude. Several records of invisibility follow up to the middle of June, when the star not being circumpolar was lost sight of at its conjunction with the sun. From May till September it is not observable from this cause. The maxima due on June 25 and September 30 were thus lost. The next, on 1857, January 5, was also lost, owing to the prevalence of cloudy weather from December 29 to January 14. The records of invisibility are, however, pretty numerous about this time, and prove it was well looked after. The maximum of 1857, April 9, was well observed, the star being seen twice before, and five times after the turning-point by me; and once on Apri] 13, as a 10°3 magnitude, by Mr. Baxendell, on a night when I had no observation. It is gratifying to find the independent comparisons of two observers —different eyes and telescopes—thus perfectly agreeing with the same unbroken light curve. U Geminorum was again lost in the summer months at its conjunction, and therefore the maximum due on July 18 escaped observation. On October 30 the variable was visiéle, but only of the 9°7 magnitude, and as it was invisible and under the 12°3 magnitude on October 27, when already five days past due, it is pro- bable that it did not surpass the observed magnitude at that maximum. An important stage of its history is now at hand. It was being sought for at Oxford, and also at Manchester, and though due on 1858, January 27, was not seen. If it appeared at all, which is doubtful, it could not exceed the 11th magnitude. But at the next due apparition, May 4, it positively did not come at all; for Mr. Baxendell was searching night after night, with his great reflector, and limited it “under 143 magnitude,”’ as shown by the short red (dotted) lines represent- ing his valuable records, at the very time it was due ata maximum. The August apparition occurred in conjunction, and the star was justly supposed to have “=x- PIRED”’ or died out gradually. But on November 16 it returned, nearly as:bright as ever, as shown by the combined observations made at Oxford and Manchester. And lastly, on February 19, 1859, it acquired a maximum equal to any previous * The red lines in the original diagram are represented by dotted lines. (See Plate I.). TRANSACTIONS OF THE SECTIONS. 41 one on record. Here again it is interesting to find the independent observations of the writer, at the Hartwell Observatory, and of M. Goldschmidt at Paris, blending so smoothly together—to form the light-curve. And I may here remark upon the advantage of free intercourse in science. But for the valuable communications of my two friends, I could only tell half my tale, and the curious failure of its appear- ance in May 1858 would have remained “‘Nor Proven!” Its truant nature is well shown by the circumstance, that out of 162 nights on which it has been sought for, it has been seen only on twenty-seven, and these distributed amongst four observers. The details of the observations of these five stars, as well as of eight others, which have in fact been the recreations of my leisure hours for some years past, after the discharge of official duties at the Radcliffe Observatory, were to have been published as a supplement to one of the future volumes of the Transactions of that establish- ment, in which they were mostly made. The untimely death of my venerated Di- rector and friend, M. J. Johnson, Esq., has interrupted this arrangement. As the various maxima and minima depend upon very different numbers of obser- vations, a systematic and just assignment of the weight or comparative value of each resulting equation has been duly regarded, and is an indispensable consideration in all such investigations. It is singular how many of the variable stars have faint companions, though whe- ther physically or merely optically double, years of accurate measurement can alone distinguish. The empirical prediction of future changes, by the deduced epochs and periods, is the first fruit, and perhaps for some time, the only yield to be expected from this field of sidereal research. These are, however, so much wanted, that with the ap- proval of my patron, Dr. Lee, and our distinguished neighbour Admiral W. H. Smyth, to whose invaluable experience and ever readily bestowed counsel and encouragement I owe the most grateful acknowledgments, the variable stars form the chief pursuit towards which the resources of the Hartwell Observatory are directed ; and an Atlas of the vicinity of every known variable, together with the determination of the standard magnitudes of the most suitable comparison stars in their immediate neigh- bourhood, is in an advanced state of preparation ; so as to relieve amateurs who are inclined to take charge of a few of these interesting and amusing objects, of the only tedious part of the process. Many possessors of small but good telescopes ex- claim in despair, ‘‘ What can I do to be useful with my small optical means, which is not better done elsewhere?’ ‘To such I would reply, ‘‘ Record the changes of some yet undetermined variable star!” It is little gain for all to be occupied on the same objects, because they appear most striking and interesting; plenty yet re- main, the elements of variation of which are still unknown ; and to supply the first good deductions of this kind ought to satisfy the ambition of any one who seeks to be useful, without incurring the outlay of money, time, and trouble requisite for the pursuit of the more advanced branches of the science. On the Effects of the Earth's Rotation on Atmospheric Movements. By Danie, VauGcuan, United States. Though much attention has been hitherto devoted to the motive power concerned in producing the winds, there is still much room for investigations respecting the cir- cumstances which modify its action. From the influence of heat in expanding the air, and the manner in which temperature varies with an increase of latitude, it has been inferred that the lower atmosphere must flow towards the equator, from remote parts of the northern and southern hemisphere, while returning currents roll back above the region of the clouds. On tracing the change which the earth’s motion must occasion on such moving masses of air, a very plausible explanation is obtained of the leading phenomena of the trade-winds. But it seems difficult to account for the geographical range of these regular movements of the air; as their extreme limits, even in the Pacific Ocean, extend only a few degrees beyond the tropics, and alter position comparatively little during the different seasons of the year. The difficulty appears greater, when we reflect that, in the torrid zone, temperature is not much 42 wteae REPORT—1859. affected by an increase of latitude, and must therefore operate with less energy in causing a general circulation of the atmosphere. My researches show that the chief obstacle to the extension of trade-winds to the temperate zones, proceeds from the diurnal motion of the earth. On the centrifugal force arising from this rotation depends, to some extent, the direction of terrestrial gravity at places between the poles and equator; the equilibrium of our atmosphere is accordingly dependent on it; and if this vast collection of air ceased to partake of the earth’s movement, the greater part of it would be compelled to remove from the tropical to the circumpolar regions, In like manner, when the airis moving towards the west, it experiences a reduction of centrifugal force, accompanied by a slight change in the direction in which it is attracted by our planet, and a proportionate ten- dency to flow towards the pole; while in an eastward movement the effect would be reversed, and there would be a steady deflection towards the equator. Whenever an extensive portion of our atmosphere undergoes a considerable change of latitude from local variations of temperature, it cannot, at once, acquire the velo- _city and the centrifugal force necessary for an equilibrium in its new location, and a retrograde movement is a necessary consequence. Accordingly the earth’s rotation, instead of disturbing the repose of our aérial ocean, only imposes restraints on the dis- ‘turbances arising from the action of solar heat. Its resistance to atmospheric move- ments (supposing friction removed, and the motive power to act in the direction of the meridian) is nearly proportional to the square of the sine of latitude multiplied by the distance the air has been withdrawn from the parallel of the place which has the same velocity with respect to the earth’s axis. This rate of variation appears to be approximately correct, whether the air be supposed to preserve its eastward velocity unchanged in its passage towards the equator or the poles, or whether cognizance is taken of the change of velocity, with which the translation must be attended, that our globe may sustain no loss of momentum by aérialcommotions. But in the latter case a higher coefficient of resistance will be obtained, though it must be diminished in consequence of the effects of friction. It thus appears that the centrifugal force attending the rotation of our planet, impedes only in a slight degree the extensive movements of the winds in tropical regions ; but it becomes a serious impediment to their prevalence on the same scale, in the temperate and the frigid zones. As the part of the atmosphere which feels most intensely the expanding influence of heat is compelled to ascend, in the vicinity of the equator it flows towards the poles, forming two vast aérial rivers, whose breadth is nearly 25,000 miles at their origin, but is reduced to about 22,000 miles on reaching the parallels of 28 degrees. Such a reduction of breadth would evidently be accompanied with an increase in the depth of the stratum of air, were it not for the decline of temperature; butit cannot fail to augment atmospheric pressure, especially at the place where the progressive move- ment from the equator is arrested by the resistance from centrifugal force. This occurs between the 25th and 30th parallels of latitude; and here the great pressure, of which the barometer gives manifest indications, causes the air to descend, to roll back towards the equator, and to participate once more in the circulation of the trade- winds. It appears, moreover, that the mere form of the earth must be an impe- diment to the extension of trade-winds to any considerable part of the temperate zone, where the degrees of longitude diminish so rapidly in length; for the belt of air which encircles the equator could not make a general movement as far as the 60th parallel of north latitude, without swelling to a height wholly incompatible with the -conditions of equilibrium. The aqueous vapour conveyed by the trade-winds is condensed into rain during the ascent of the air at or near the equator; and the evolution of heat attending this condensation must, according to Professor Espy, be regarded as the chief source of power which maintains the great circulation of the tropical atmosphere. He has long ascribed storms to the local condensation of vapour, and he adduces evidence to show that the winds blow to the point at which the most heavy rain is descending ; -but Dr. Hare attributes this centripetal movement to the constant discharge of elec- tricity, which the moisture of the air enables to escape from great elevations. Now, whatever part heat and electricity may act in these phenomena, the results must be ‘modified in the same manner by the diurnal motion of our globe. As the impedi- ment which centrifugal force gives to atmospheric movements augments with every TRANSACTIONS OF THE SECTIONS. 43 increase of latitude, it is evident that in our hemisphere the air must be drawn from the greatest distance and with the greatest velocity on the south side of a storm; and this, taken in connexion with the constant eastward deflection of the moving mass in its passage to the north, will account for the superior force of south-west winds in the north temperate zone. The air pressing from the north and south to the place at which the greatest rain occurs, must be deflected in opposite directions ; and on this principle it has been proposed to account for the rotation of storms. But the eastward and westward winds must cooperate in producing the same result, the former being deflected to the south and the latter to the north, from an excess and a deficiency of centrifugal force. The spiral motion, generated in this manner, prevents the atmospheric pressure, at the centre of a storm, from being increased by the influx of the surrounding air, and contributes to make the violent movement extend to the bottom of our aérial ocean. As the air on the east side of the great vortex cools by retiring from the equator, it becomes less capable of retaining its aqueous vapour, while an opposite effect takes place on the west side, where the temperature of the air increases with the change of latitude. From the greater abundance of rains which accordingly fall on its east side, the focus of a rotating storm must be constantly shifted in an eastward direction ; but between the tropics the movement depends on less effective causes, and the course is mainly determined by the direction of the trade-winds. In temperate climates a tendency of the storm to recede from the equator must proceed from the superior violence of south-west winds, to which allusion has been already made. Accordingly the present theory, without involving any new hypothesis, appears to furnish a very satisfactory explanation of the leading facts which meteorologists have discovered, respecting the rotary and orbital movements of tempests in different regions of the earth. Theconstant change in the position of the focus, to which the whirling mass of fluid is directed, appears to be the cause not only of the east or north-east course which storms take in our climates, but also of the centrifugal motion of the air which observers have occasionally noticed, and which Espy ascribes to the impulse of de- scending drops of rain. Ona System of Moving Bodies. By A.S.S. Witson. METEOROLOGY. On the Semidiurnal and Annual Variations of the Barometer. By Joun ALAN Brouy, F.R.S., Director of the Observatories of His Highness the Rajah of Travancore. In the twenty-second volume of Poggendorff’s ‘ Annales’ (pp. 219 and 493*), M. Dove showed, in discussing observations made at Apenrade, that when the tension of vapour in the atmosphere is subducted from the whole atmospheric pressure (for each hour), the remaining diurnal variation of dry air pressure has a period of twenty-four hours like that of the elasticity of vapour itself, only that the maximum of the one occurs at the same time as the minimum of the other, these epochs coinciding nearly also with those of highest and lowest temperaturet. M. Dove has shown that this result may vary under different circumstances ; thus in a place far from the sea, to which no sea breeze can make up by day what the ascending current carries away of vapour from the lower strata. the curves of the elasticity of vapour and of dry air will march together ; since both fall at the warmest time of the day, the dry air as well as vapour will be carried up by the rising current, and flow off sideways. For a decidedly continental situation, then, Wwe may expect that the maximum of the morning will disappear in the combined pressure measured by the barometer, which will happen for places in the neighbour- * * Cited in M. Dove’s paper “ Bericht,”’ &c. der Wiss. zu Berlin, Marz 1846, p. 54, + Ibid. p. 54. : 44 REPORT—1859., hood of the sea only for the pressure when the elasticity of vapour has been deducted. Between these extremes of sea and continental climates a gradual passage will occur*. M. Dove’s hypotheses (for there are more than one included in this statement) were presented to the English reader first by General Sabine, in a Report on the Meteorology of Toronto, published in the Reports of the British Association for 1844, p- 50, and examjned by him with reference to a sea climate, that of Bombay, in the Reports of the British Association for 1845, p. 73. In the Reports of the Association for 1845, p. 12, the Committee on Magnetical and Meteorological Observations put the question, “‘ Has M. Dove’s resolution of barometric fluctuation into two elements received any confirmation?” In the “ Bericht,” &c. of the Berlin Academy of Sciences (March 1846), M. Dove dis- cusses observations made at Java, and conceives that his discussion answers the question decidedly in the affirmativet. Mr. Broun maintained in 1846, in his discussion of the Makerstoun Observa- tions, the insufficiency of M. Dove’s hypothesis; but as this has been adopted lately by Sir John Herschel in a treatise on meteorology, Mr. Broun considered the time was come for a careful examination of the facts on which M. Doye’s method professes to be founded. Two hypotheses are included in that method :—1st. That the tension of vapour deduced from the psychrometer observations is due to an atmosphere of vapour pressing with a weight equal to that tension. 2nd. That through the action of the solar heat an ascending current of air is induced ; the air is expanded and overflows above over colder localities. In order to test the first hypothesis, Mr. Broun made some observations (in January 1857) on the sea-shore of Travancore, which were compared with observa- tions made in the Trevandrum Observatory eight miles distant. These observations showed that the variations of the barometric pressure were to the same amount at both stations, that the difference of temperature was about 0°'8 Fahr.; nearly that due to the difference of heights (about 160 feet), but that the difference of computed vapour tension varied considerably ; these tensions were as follows :— Tension of vapour. 19}, 22h, 2h, 4ih, 93h, in. in. in. in. in. Channavilla ws... 0°645 0°643 0°690 0°692 0°723 Trevandrum ......... 0°543 0°562 0°641 0°669 0°685 Difference ............ O°102 0°081 0°049 0°023 0°038 The difference of tensions was upwards of one-tenth of an inch at 7 a.m. and less than one-fourth of that quantity at 4 p.m. As this difference would have been shown at the sea-shore nearest to Trevandrum (three miles distant), it was pointed out that the tension of vapour thus determined, depending wholly on the different temperatures of evaporation at the two stations, was quite a local phenomenon, vary- ing with proximity to the source of evaporation, the temperature and the pressure of the atmosphere, and the rate of diffusion of the vapour itself under such pressure. On this ground the hypothesis fails completely. Indeed the diurnal variation of pressure of computed dry air was shown to have the 10 a.m. maximum as well marked at Chunnavilla as the barometric variation. General Sabine had obtained a somewhat similar result from the Bombay observations; and the double oscillation still remaining in the dry air pressure, was explained by a supplementary hypothesis depending on sea and land breezes. It was here noted by the author that the Bombay Observatory was within a hundred yards of the sea, in a position quite resembling that of Chunnavilla Cottage; and that the distinctness of the double maximum and minimum in the calculated dry air pressure, instead of being due to a sea and land breeze, was simply due to the small diurnal range of the computed vapour tension, which in the arithmetical operation of subtraction was insufficient to disguise the barometric law. A few miles inland the disguise would have been more marked. * Cited in Mr. Dove’s paper “ Bericht,” &c. der Wiss, zu Berlin, Marz 1846, p. 54. This is nearly a literal translation of M. Dove’s statement. T Ibid. p. 60. TRANSACTIONS OF THE SECTIONS. 45 Mr. Broun then showed the insufficiency of M. Dove’s method, by a discussion of observations made at Makerstoun in Scotland in 1843-46. Inthe winter quarter it was proved that, so far from the morning maximum disappearing, the diurnal varia- tion of dry air pressure showed a hetter marked double oscillation than was exhibited by the barometer. Further, it appeared that the amount of the diurnal oscillation of the barometer had no relation whatever to the amount of diurnal oscillation of vapour tension or of temperature; the sum of the barometric diurnal oscillations at Makerstoun being greatest when the amount of the diurnal variations of vapour pressure and of temperature were least. It was also remarked that there were secondary maxima of vapour pressure which did not show themselves at ¢ll in the barometric results ; or that when the tension of vapour by the psychrorneter observa- tions seemed to increase, the total pressure, as measured by the barometer, gave no symptoms of it. M. Dove had brought forward as a proof of the accuracy of his method, the statement that in places far in the interior of the Asiatic continent, such as Cathe- rinenburg, Nertchinsk, &c., distant from large masses of water and with dry atmospheres the double diurnal oscillation was not shown in the barometric observa- tions. Mr. Broun pointed out that this should not depend upon the mean dryness of the atmosphere, but upon the diurnal variation of vapour tension as computed by the psychrometer. He compared the diurnal variations of vapour tension at Nert- chinsk and Makerstoun in 1844, which were as follows :— 4—5 a.M. l pM. Range. in. in. in. At Nertchinsk ........ese000. 0°122 0'155 0:033 At Makerstoun ....ee000062 0°267 0°301 0°034 As the range is as great at one place as at the other, there can be no better reason (as faras this point is concerned) for the barometric oscillation being single at Nertchinsk than at Makerstoun. But in order to test the method more perfectly, one of the dryest months (January) of the year 1844 was chosen; in that month the diurnal variation of vapour tension at Nertchinsk was between 0008 in. at 6 a.m. and 0°017 in. at 1 p.m. The oscillations Were compared with those for the same month at Makerstoun in Scotland; the comparison will be best understood by the following Table :— Oscillations of Barometer and Dry Air Pressures at Nertchinsk and Makerstoun, January 1844. ; | Station. a 8 p.m. | Change. || 5 a.at. | Change. || 10 a.m.) Change. |/ 1 p.m. | Change. in. in. in. in. in. in. in. in. Nert- Barom....|27°830 |— 0-021 ||27-809 |+-0-020 ||27-829 ~0:027 |27-802 |-+-0:024 chinsk | Dry air...|27:819 —0-018 ||27-801 +0:015 ||27-816 | —0-031 ||27-785 |-+-0 034 See Makers Barom....|/29°705 |—0-020 |29°685 |+4+-0:023 ||29-708 | —0-020 | 29-688 |4-0:017 toun... | |Dry air...|29°501| 0-019 |29-482 |+-0-011 |/29-493 | —0-031 ||29-482 |-+-0:039 It will be seen from this Table that the barometer diurnal oscillations at Nertchinsk, in the interior of a great continent, for the month of January 1844, agreed within a few thousandths of an inch with those for Makerstoun, a quite insular locality ; the greatest difference being in the afternoon minimum, which falls ‘007 in. more at Nertchinsk than at Makerstoun. The diurnal variation of dry air pressure shows a distinct and well-marked double maximum and minimum like that at Makerstoun. Mr. Broun concluded his examination of the sufficiency of M. Dove’s method, by a discussion of observations made in ‘the observatory of His Highness the Rajah of Travancore at Trevandrum ; from which it appeared that the double diurnal maximum and minimum of dry air pressure were shown in the dry quarter, that of land and sea breezes; in the monsoon quarter, that of continuous N.W. winds; and in the means for the whole year ; but most distinctly and regularly in the monsoon quarter, when no land and sea breezes are blowing. 46 ; “REPORT—1859. With reference to the second hypothesis, that of overflowing currents, it was stated that not only were there no grounds for it, but there were several facts quite opposed it. Among others, it was pointed out that the best marked of the semidiurnal varia- tion of the barometer at Makerstoun in 1843-46, was that for the night (9 P.m. to 9 a.m.) during the winter quarter, when the tension of vapour and temperature of the air were nearly constant. Mr. Broun now adduced the results of a series of observations made under his direction, by fifteen observers, at Trevandrum, at the base of the Ghats, twenty miles distant ; and at three other stations, rising successively on the sides of the Agustier Mallay, by 1500 to 1700 feet, the highest being the Peak Observatory, 6200 feet above the sea-level. These series show completely the insufficiency of all the usual hypo- theses. The following Table contains the mean barometer oscillations derived from a month’s hourly observations in the commencement of 1859 :— ks "dan, | Malling. | mom | Mandy, | Beaks in. in. in. in. in. 9 p.M. 0 3 A.M... ceeeeee —0:070 | —0:074 | —0-076 | —0-075 | —0-082 BAM. to9 AM. ccc +0-091 | +0-090 | +.0:093 | +0090 | +0-090 9 A.M. tO 3 P.Mi..ccecsceses —0:126 | —0-115 | —0:096 | —0:082 | —0:070 3B P.M. $0 9 PoMesssseeceeeee 40-105 | +0-099 | +0-079 | +0067 | +0-062 It appeared from these observations that the night oscillations (that between 9 P.M. and 9 a.m.) had nearly the same value at Trevandrum three miles from the sea, and at different heights on the Ghats twenty miles from Trevandrum ; the oscillation being on the whole greatest at the highest station. The day oscillation diminishes as we ascend, the diminution being partly due to the expansion of the atmosphere during the day, by which part of it previously below the upper stations is carried above them. It seemed probable that the oscillations were chiefly due to an action upon the upper or dry atmosphere, indicating, the author conceived, an electrical or magnetical result. Mr. Broun proposed in 1857 a theory of the diurnal variations of the barometer, which agreed to some extent with one communicated to him by Dr. Lamont ina letter (dated June 4, 1859), but published elsewhere by’ Dr. Lamont. Dr. Lamont’s hypothesis was founded on the electrical action of the sun, whereas Mr. Broun’s, as at first proposed by him, was founded on the sun’s magnetical action; he proposed in the present state of the facts to place both hypotheses under the following general form. The sun by its electrical action (static or dynamic) on our atmosphere and the earth gives to the atmosphere an ellipsoidal form with the longer axis nearly under the sun ; this ellipsoid, foilowing the sun, produces the semidiurnal oscillation of the barometer, the extent of this electrical action probably depending on the relative dryness of the air. In Dr, Lamont’s view, the action is electrical induction on the atmosphere (the sun’s electricity supposed positive) ; in Mr. Broun’s view, magnetical induction on the atmosphere and earth; by both the part next the sun is attracted, and on the opposite side repelled, or vice versd. ‘The author now referred to the annual variation of the barometer, and concluded— That the annual variation within the tropics was quite a local result, the range of the monthly mean pressures being about one-tenth of an inch for each four or five degrees Fahrenheit of range of monthly mean temperature. That the mean pressure of the whole atmosphere is greatest in December or January, and least in June or July; this difference being more marked when the computed dry air pressures are considered. Finally, the author remarked that if the sun’s action on our atmosphere resembled its action on the gases of comets, the pressure should become greater as the earth approached the sun, that is in December; but it was believed that the difference found between the pressures in December and June, was chiefly due to the greater a TRANSACTIONS OF THE SECTIONS. 47 humidity of the air in June than in December, by which, according to the hypothesis for the diurnal variations, the electrical action is diminished. According to Dr. Lamont’s mode of considering the solar action, the barometric pressure should be diminished as the earth approaches the sun. ‘The whole question of atmospheric electricity, and its relation to the electricity of the earth, is, however, in a sufficiently vague state to render a just view of the sun’s supposed electrical or electro-mag- netical action, if the magnetical view be taken, somewhat indefinite; but whether we suppose the atmosphere positively electrified and the earth negatively, or with M. Peltier, that both are resinously electric, the latter more powerfully than the former, we must consider not only the action on the atmosphere, but also that on the earth, and the vapours which rise from its surface, as well as their reactions on each other. On the Fall of Rain in Forfarshire. By ALExAnDER Brown, Observing Member of the Meteorological Society of Scotland, &c. Arbroath. | Barry, Hon: Hit Strichen, | Craigton. |Dundee.| Kettins. eS Monthly 2 rf ° U ° i ° “ ° vi ° i ° i ° Ul avEraBe Latitude N.| 56 34 56 293/56 423/56 33) 56 33% | 56 314 [56 273] 56 32 |,,,.0f Long. W...| 2 35 |247|231| 251) 2493] 250 |259| 3 133 Altitude ...) 65 ft. | 35 ft. | 15 ft. | 500 ft.) 500 ft. | 500 ft. |100 ft.| 240 ft. in. in. in. in. 1-21 1:21 151 | 1:117 1858. in. in. in. in. January ...| 0:923 | 1:25 | 0-60 | 1:09 in 1:15 February...| 1:037 | 1:09 | 0:70 | 1:19 131 1:29 0 92 1:20 | 1:093 March......| 1:277 | 1:23 | 1:60 | 1:47 1:50 1:55 116 1:20 | 1:378 ApH y.5005 1:287 | 1:25 085 | 1:79 1:85 1-92 1-40 1:55 | 1:487 May ...... 2-093 | 1:97 | 1:80 | 2:00 | 2:07 2:25 1:80 2°42 | 2-050 June ...... 1513 | 1:32} 2:32 | 1:29 1-44 1:33 3°37 1:77 | 1-794 July ......, 3076 | 3:75 | 3:10 | 3:35 3°63 3°44 3:60 6°74 | 3835 August ...| 2°270 | 2:44 | 2°27 | 2-25 2°45 2:25 2:80 3:10 | 2-479 September! 2°023 | 2:76 1:85 | 2-70 2°80 2-73 2:34 2:85 | 2:506 October ...| 2°665 | 3°28 | 2-63 | 3°10 3°23 3:18 2:80 TT oes 2:995 November | 1°874 | 3:01 | 2:20 | 3:25 3°40 3°20 2°45 218 | 2°695 December | 4315 | 3:47 | 3:00 | 3-91 4:17 3°95 3°62 345 | 3:735 26°82 | 22-92 27°39 29:00 | 28:30 | 27:55 | 27:97 |27°159 11 months. The above Table gives, for the year 1858, the monthly fall of rain at eight stations, where rain-gauges are kept, in Forfarshire, extending from Montrose on the east to Kettins on the west. The distance of these two extreme stations from each other is about thirty miles, and the district embraced by the eight stations comprehends about one-third part of the whole county. The first three stations named in the Table and the last, are four of the Scottish Meteorological Society’s stations. The three stations, Hillhead, Strichen, and Craigton, are in the neighbourhood of each other, and situated in the parishes of Monikie and Carmylie around the reservoir at Monikie, from whick the town of Dundee is supplied with water. The latitudes and longitudes of the different stations are taken from Arrowsmith’s large map of Scotland. The altitude above sea-level of Arbroath and Barry stations is taken from the Ordnance Survey, and the altitude of Monikie reservoir is 440 feet, as found from the survey made by Mr. Leslie, C.E. in connexion with the construction of the Dundee Water- Works ; the stations named are higher than the reservoir and estimated as in the Table. The station at Kettins is not far distant from some of the highest hills in the Sidlaw range. The rain-fall there for eleven months is greater than for the whole year at any of the other stations, excepting Strichen and Craigton, which arises from the unusual rain- fall of 6°74 inches in the month of July. For the whole of Scotland, the rain-fall for 1858, as given in the Quarterly Reports of the Scottish Meteorological Society, is 33°91 inches,—greater than that of the above eight Forfarshire stations by 6} inches. The following Table gives the annual rain-fall at five of the above-named stations for six years, from 1853 to 1858, both inclusive, with average annual fall for that 48 -REPORT—1859. period. It will be noticed that the annual fall increases with the altitude of the station above the sea-level. Years. Arbroath. | Hillhead. | Strichen. | Craigton. | Dundee. oe ae as in. iat in. in. in. in. IB5D5%, scatessace --| 27-602 | 33°46 36°46 34°75 31-78 1Sb4 siieeeets veeee.| 20°818 29-06 30°19 31:83 24°31 1855....... aeaeeee 21:026 | 26:14 27:43 26°66 22-70 WS56:. ccecaceaven 32°274 39:45 41:49 39-93 35-29 1857...... seeserecs 23°739 32°04 33°31 32-51 27°53 LSSS ctccsnese sboeee 24:353 27°39 29-00 28°30 27:55 Average of 6 years...| 24:969 | 31:51 32°98 | 32°33 28°19 Remarks on the Climate of Orkney. By the Rev. Cuartes CLoustTon, L.R.C.S. Edinb., Pres. Ork. Nat. Hist. Soc. &c. Orkney is situated further North than any part of the mainland of Scotland or the Naze of Norway, and nearly in the same latitude as Stockholm on the East, and Cape Farewell on the West; yet its climate is one of the most equable in Britain, and this is ascribed to the effect of the surrounding oceans, and particularly of the Gulf- stream. From meteorological observations made in Orkney for nearly thirty-three years, tables of which were laid before the Section, it has been ascertained that its mean annual temperature is not only equal to that of the north and middle of Scotland, but even to that of the south border, or 46°*26; while Dumfriesshire is 4° or 5° colder than Orkney in winter, it is above 3° warmer insummer. This arrangement may be pleasant, or favourable to animal life, but it is unfavourable to vegetation, particularly to trees. Evergreens are killed by the sea-spray in winter. The difference between the mean temperature of the warmest and coldest months is only about 17°, never having risen so high as 62°, nor fallen so low as 31°. That the Atlantic moderates the extremes and elevates the temperature of winter, more than it depresses that of summer, is evident, when we consider that in 1858 its mean temperature was about 33° above that of the air, which it exceeded during ten months, and only fell below it during Juneand August. It has not yet been found colder than 43°, and the mean of three years is 49°56, or more than 3° above that of the air. In the inland parts of Britain the greatest heat occurs about the middle of July, and the greatestcold about the middle of January ; and the months equidistant from these are most nearly of equal temperature. In Orkney, however, January and February are equally cold, and July and August equally warm; and the months equidistant from these correspond most nearly, as March and December. This retardation of the period of extreme heat and cold is ascribed to the influence of the sea, which is neither so quickly heated in summer, nor cooled in winter, as the surface of the land. A table was produced showing the mean monthly atmospheric pressure for the last twenty years, which does not show any great peculiarity of climate. It attains its greatest height in May, and gradually descends on each side, the only exception being in September, when it takes a step upwards. The mercury has been observed as low as 27°69 inches, and as high as 30°76 inches, giving a range during these twenty years of 3°07 inches. A table showing the quantity of rain each month for the last eighteen years was also produced, showing that the mean annual quantity for that time is 36°53 inches at the place of observation on the west side, but it is much less on the east side of the islands. As in the former tables, so in this may be observed a gradation from the minimum to the maximum quantity ; thus May has the least rain as well as the highest barometer, and it gradually increases on each side till October, which is the wettest month, September being the only exception. From a table giving the direction of the wind for thirty-two years, it appears that it blew from the W., S.W., S, and S,E., 6964 days, while from the opposite four points-it TRANSACTIONS OF THE SECTIONS, 49 blew little more than half that time, or 4041 days. Does Orkney owe much of the mildness of its climate to this prevalence of S. and W. winds? Two other tables were given—one embracing a great variety of particulars regard- ing Orkney, the other the same particulars regarding all the stations of the Scot- tish Meteorological Society. From these it appears that the instruments do not show more dampness in Orkney than in the other stations. Observations on the Natural Obstructions in the Atmosphere preventing the view of Distant Olyects on the Earth's Surface. By ALEXANDER CRUICK- SHANK, A.M, Aberdeen. I wished to determine the frequency with which the daily extreme limits of view from any fixed station, over an extensive range of country, are circumscribed by natural causes, viz. haze, showers, and mist or low clouds. For this purpose I made daily observations about noon, during the years 1856, 1857, 1858, from the vicinity of Aberdeen, on the distance seen along the South Deeside Grampian range of mountains, which run in a S.W. direction from Aberdeen, and of which the main tops are visible in fine weather from that vicinity, at the respective distances of five, ten, twenty, thirty, forty, and fifty miles. These tops are called Clochendichter, Caernmanearn, Caerloak, Mt. Battock, Mt. Keen, and Lochnagar, the last one being nearly in the S.W. corner of Aberdeenshire. They are all nearly in a line, and were taken as fixed points for noting the varying distances seen. It was found that the obstructions to distant vision, caused by showers, and by mists or low clouds, entirely obscured the view at once, at the nearest points to the observer at which they existed. When, however, haze circumscribed the view, it was found to increase gradually, with the distance, beyond the nearest point at which it began to be perceptible, and this was often only one or two miles off, till its density entirely prevented further vision beyond the distance of five miles and upwards. Taking the average of the observations for the above-mentioned three years 1856, 1857, 1858, it was found that the view, about noon, extended to fifty miles, or to Lochnagar, on ninety-four days during the year; but the state of the atmospheric obstructions to vision at that distance showed that, on many of those days, the view must have reached much further, had the observer been at a higher level. On fifty- two days the view was limited to forty miles, or to Mt. Keen, the nearer hills being also seen, or it was less than fifty miles; Lochnagar, though seen in clearer weather from the point of observation, being rendered invisible by the atmospheric obscurities referred to. On forty-five, fifty-one, thirty-nine, and sixty-nine days during the year, the view at the time of observation was respectively limited to the distance of thirty miles, or Mt. Battock, twenty miles, or Caerloak, ten miles, or Caernmanearn, and five miles, or Clochendichter, more distant vision being completely prevented by the atmospheric obscurities beyond those distances. In fine, on fifteen days in the year, mist and showers circumscribed the view within one mile of the place of obser- vation. Simultaneous observations in other directions from the point of observation, gave similar results, in as far as the inequalities of the earth’s surface permitted a suffi- cient length of radial view. Had, therefore, the view about noon over the earth’s surface extended as far in all directions as in that of Deeside, there would have been visible on an average of 94, 52, 45, 51, 39, 69, and 15 days in the year, portions of that surface included within circles of the diameters of 100, 80, 60, 40, 20, 10, and 2 miles respectively. From the similar variability of climate throughout Britain, the above results may be regarded as true, or nearly so, of the rest of the island. They show that angles sub- tended by objects at the distance of fifty miles or more, such as enter into the Ordnance Survey of the country, could not, on account of haze, mist, &c., be observed with sufficient accuracy about noon on more than ninety-four days in the year. There is, however, at that time of the day another very frequent and great obstruction to such observations, viz. the tremor of the atmosphere, on the frequency and amount of which the present observer does not feel qualified to report. But it is well known that, owing to the two causes now mentioned—obscurity and unsteadiness of vision— the Ordnance surveyors, with the whole day at their command, have sometimes been 1859. 4 50 REPORT—1859. obliged to remain for weeks at a station, before getting a favourable opportunity to observe some of their angles. Note.—From observations made on the subject of the above paper during the year 1859, the view from the vicinity of Aberdeen was found to be limited to the above- mentioned distances on 128, 47, 31, 41, 30, 76, and 12 days respectively.—Feb.1860. On the Diurnal Variation of the Barometer. By T. DAviEs. The author examines the effect of the sun’s heat on a column of air of the height of the atmosphere about the torrid zone, where the heat is greatest, and the days and nights nearly equal. The main phenomena of the diurnal variation are, he finds, represented by this cause. The communication was illustrated by diagrams, which showed two chief maxima and two lesser maxima, with the corresponding intervening minima, at critical hours of the day. On Mild Winters in the British Isles. By Prof. Hennessy, F.R.S. The author pointed out the circumstance that the meteorological observations made during the late remarkably mild winter tended to confirm the law which he had already announced in a letter to General Sabine, which appears in the ‘ Proceedings of the Royal Society’ for 1858, This law is, that during mild winters the coast stations exhibit an increase of temperature more than inland stations, and that the tempe- rature on the west and south coasts approaches towards uniformity. In France, as pointed out by M. Liais, the first part of this law is found to hold good, as evinced in the comparative climatology of Cherbourg and Paris. Mr. Hennessy referred these phenomena to an abnormal extension of heat-bearing currents across the Atlantic. The prevaling westerly and southerly winds would, under such circumstances, transfer to our shores a great portion of the warmth which they had received from contact with the heated waters at remote portions of these currents; for the condition of the ocean bathing our shores, would be favourable to the preservation of such warmth in the strata of air passing over its surface. From the greater stability of such currents than those of the atmosphere, and from the important influence they undoubtedly exercise upon our climate, he is led to infer that we are rapidly ap- proaching a period when it may become possible to foretell whether the winter shall be cold or warm by knowing the conditions of temperature and the movements of currents in the Gulf of Mexico and the Atlantic during the summer and autumn. On the Distribution of Heat over the Sun’s Surface. By J. J. Murpuy. On the Aqueous Vapour of the Atmosphere. By Rear-Admiral FirzRoy, F.R.S. In order to show why this subject was of urgent importance, the author gave a brief description of the origin, nature, and objects of the Meteorological Department of the Board of Trade, which was instituted to collect and publish meteorological observations made at sea; and explained that he now required the opinions of com- petent authorities as to the best method of publishing a great accumulation of valu- able observations. Referring especially to the division of opinions of some scientific men on the question of aqueous vapour, and the reduction of barometrical observa- tions, the Admiral quoted passages from the reports of Col. James and Prof. Patten, printed in the third Number of ‘ Meteorological Papers’ published by the Board of Trade in 1858. Admiral FitzRoy then submitted to the President of the Section that it would be desirable to elicit some authoritative opinions on the subject in question, before he proceeded to other meteorological perplexities which he had in reserve for another occasion. On Atmospheric Waves. By Rear-Admiral FitzRoy, F.R.S. As so much has been said during the last few years about ‘‘ atmospheric waves,” I would refer to them here. If wind veers round the compass in the course of two or three days (more or less), or is many days in making a circuit—invariably, as it TRANSACTIONS OF THE SECTIONS. 51 goes round, the barometer rises or falls according to the direction or strength of the wind. Supposing a diagram to represent 36 hours, and divided into spaces of three hours each along the upper horizontal line; while below, points of the compass are shown, from north around by east to north again, and continued to south; and at the side a scale of inches and decimals, from 28 to 31. Then suppose that the wind has gone round the compass once, or say once and a half, as happens occasionally ; and that it has been an extreme case of depression, as ina storm. ‘Then, if from (say) 30°3, with the wind at north, a shifting occurs, first towards the north-east, and then onward in the same direction around the compass—as the wind so shifts to the north-east, and is about to shift towards the east and south, the baro- meter foretells it, or falls beforehand. When the wind is north-east the mercury is lower, probably, than when it was at north. As it gets to the east the mercury falls, and gets lower still at south-east, and falls still more to south and south-west, where it is probably the lowest, because it feels the effects of the south-westerly or equa- torial current most then, and may be down, let us suppose, to 28°2 inches. As the wind shifts round to south-west, west, north-west, the column in the tube rises, till, perhaps, the wind is north, or even north-east, when it may be as high as 30°8: it has been known in this country as high as 309. As the wind goes round again to the east and south-east and south, the barometer falls as before, and a line or curve traced upon paper, representing these falls and rises, or oscillations of the barometer during a certain time, say these 36 hours, has an appearance like the outline of a wave of water; but as these apparent waves or undulations take place ewactly as the wind shifts, and proportionally to its strength, and as, if the wind remains in one quarter for some days, or say two or three weeks together, the curve becomes almost a direct line, remaining at about the same elevation, it seems that there is an intimate and immediate connexion between such a curve or wave-line and the oscillation of the mercury, though not necessarily between the curve and any undulatory move- ment of the atmosphere above our heads. Ifa body of the atmosphere above us swelled upwards, like a wave, and fell again, as some suppose, as it were in “ crests ” and “ troughs,” how should we reconcile it with the fact of there being various cur- rents passing over each other in the atmosphere from different directions? Aéronauts who have been up in balloons know that from one stratum of air they passed into another and another, and perhaps a fourth also, moving in different directions. There cannot be vacancies between the undulations of various strata of air. These different bodies of atmosphere could hardly be undulating like waves while having spaces between them, and interferences of cross movements. Waves of ocean have only elastic air above them, which does not impede their rise and fall materially ; and they are only superficial, not reaching far down. Were there a raising of any part of the mass of air, the lighter or equatorial portions, or winds, would rise the highest, and would expand; but, according to the ‘‘ Wave theory ” (here controverted), the reverse is the fact; you have the lowest part of the apparent trough of the wave, with the lowest barometer, that is, with the air, which is the lightest and most expanded, and ought therefore to rise up the highest ; and you have, coincident with the heavy dry air, the highest part, or what is called the “crest” of the wave. Considering then these facts, and the exact correspondence of the movements of the mercury with the wind’s direction, besides noticing the extreme variability traceable in such an atmospheric wave (which can hardly be conceived to be motionless for weeks, as in the case of a steady north-easterly wind, and then going into extraordinary irregularity during a day or two), we are led to the belief and assertion that what are commonly called “ atmospheric waves ” are rather delusive ; and that there are waves in any line indicating oscillations of the barometer, but not such, in the atmosphere itself, as are usually adverted to by the expressions “trough ” and “ crest.” Mr. Birt drew particular attention to these supposed undulations of atmosphere, by papers read at meetings of the British Association, and by a special Article in the ‘Admiralty Manual of Science.’ Sir John Herschel, Le Verrier, and other great au- thorities then countenanced Mr. Birt’s theory and apparently sanctioned his opinion. Yet there is so much argument against those views, that even the highest names scarcely warrant their implicit adoption. That there must be undulations in the atmosphere—constlituted as it is—cannot be doubted ; but that the curve traced on 46 52 REPORT—1859. paper, representing the oscillations of a barometer as the wind veers round the com- pass, corresponds to a mechanical, wave-like undulation of the body of atmosphere, is not proved. We may demur to it on these grounds. First, the curve so traced on paper varies, not only with the barometer, but with the direction of the wind, which is inva- riably accompanied by change of pressure, consequent on the greater or less action of polar or equatorial current. Secondly, while the wind remains in one quarter, the curve or line, taken as that of a wave, remains almost unvaried, except in consequence of altered strength of wind or much rain, which have each a comparatively small effect. Thirdly, the lowest part of the curve (called the trough of the wave) always cor- responds to the lowest barometer, or lightest air ; whereas it is the lightest air that rises highest, as instanced at the equator ; and therefore the crest of an atmospheric wave (so to speak) ought to be over the place of lowest barometer. Fourthly, aéronauts always find, and the upper clouds often show currents above, very different from those below. These superposed and successive strata, in rapid cross motion, must tend to destroy undulation. I am aware of what Sir John Herschel has written on this subject (atmospheric waves) in his invaluable ‘ Essay on Meteor- ology,’ in the last edition of the Encyclopedia Britannica; but with the utmost de- ference I submit, that his experiment—on the undulations transmitted through suc- cessive (coloured) strata of fluids ix a vessel—did not meet the case of fluid strata moving horizontally, in various directions, across each other. That there are tidal waves in the atmosphere, caused by the sun and moon, ex- periment has proved; but that they are very small has also been demonstrated. This subject, however, has yet to be investigated, by means chiefly of the accurate barometrical measures instituted and carried on by Government during late years, in many parts of the world, and especially at sea. Such waves as these would follow their causes—in periodic times—and no, in utter disregard of sun and moon, only correspond to direction and strength of wind. Meteorological Observations made at Huggate, Yorkshire. By the Rev. T. Rankin. This was a series of tables and observations on the most remarkable meteorolo- gical phenomena observed during the year 1858-59 in Yorkshire, in continuation of a similar contribution continued for many years by the same author. They in- cluded observations with tables on barometer and thermometer, wet-bulb thermo- meter, rain-gauge, winds, aurora, the comet, and other remarkable phenomena, such as thunder-storms. On Tables of Rain registered at Georgetown, Demerara. By P. SANDEMAN. These Tables were constructed with the view of ascertaining what relation, if any, exists between the motion of the moon in declination and the state of the weather. The idea entertained was that the quantity of rain which fell during the time of the moon’s motion in declination, changing from north to south in the northern hemisphere, and from south to north in the southern hemisphere, would be found in excess over the quantity which fell during the time the moon is crossing the equator from south to north, or from north to south. The abstract Table No. 5 shows this to be the case in four years out often. In regard to the absolute amount of excess over the ten years, the theory holds; the excess when the moon is over the northern hemisphere being 32 inches, and when it is over the southern hemisphere 31°7 inches. The conclusion of the paper exhibits some points of interest. The author remarked that during the years in which the theory fails are to be noted the following pecu- liarities :—The rains during 1849 were excessive, amounting to 127 inches; it rained almost all the year, reckoning from the preceding month of November, During the months of May, June, and July of that year, nearly 60 inches fell. During the year1851, the rain, instead of being confined as usual to certain months, began to be more distributed over the year. In fact the rainy and dry seasons were scarcely distinguishable. . TRANSAOTIONS OF THE SECTIONS, 53 The year 1854 resembled 1851; and during the year 1855 heavy rains fell during the mouths of February and March, which is quite unusual ; and from August 1855 very little rain fell till May 1856, although the drought was not so great as that of 1845 and 1846. It is remarkable that it was during 1851 the yellow fever prevailed ; and about the year 1854 the cholera appeared in the colony for the first time. There is an intimate relation between the phases of the moon and its period of crossing the equator. On the 21st of March the sun is on the equator, and new moon must happen at a period of not more than about fifteen days from that date, either after the 6th of March or before the 5th of April. Taking iato account the inclination of the moon’s orbit to the ecliptic, the moon cannot be more than twelve degrees from the equator at these times. This the moon will run down in less than two days; so that about the equinoxes the moon must cross the equator on an average about one day and a half before or after new moon. In like manner in June, the moon, if confined to the ecliptic, would always cross the equator at a period after new moon of nearly the same interval, about twenty-two days, on whatever day new moon happened; but owing to the inclination of the moon’s orbit to the plane of the ecliptic, the interval is sometimes a day and a half more or less than the average. In fact at any period of the year the number of days after new moon, when the moon crosses the equator, is nearly constant, and would be so if the earth and moon’s orbits coincided with the plane of the equator. As it is, the interval for different years at about the same period varies rarely more than two days. The average number of days for each month, when the moon crosses the equator after new moon, is exhibited in the following Table :-— ARCs mlesinisieieisia 0) September ..cssecues 14 PRP EM Mts cess creces Siele . 20 October Veteciccte team Lice UAE clawicve sige Weide srs sts 4 2o INOVemnber catnis> seas 9 BROCE Mie tsievcescsnece 21 Weceneers.. aatieiele sicteie ne nil SID Yieatets) efoisiaj>.= sjsiepiebe shod S HANUATY? oilers cheaineiateisist On UNUPTESUMIYs cieielete a elses civ), 16 WeEDEHArY. « ciciclelefelerstisiaihs, boas From the facts which have been elicited from ten years’ observations, from 1846 to 1856, taken at Demerara, we must arrive at the conclusion that there are some grounds for the truth of the popular idea, so long and so universally entertained, of the influence of the moon on the weather by those classes whose opportunities lead them to judge of the matter. If the facts which have been elicited should be confirmed by another series of observations at Demerara, or from series of observations already in existence taken at other localities favourably situated, the existence of an influence of the moon must become a. scientific fact, and one the knowledge of which will prove of great import- ance to the future progress of the science of meteorology. There are various reasons why the popular idea of the influence of the moon on the weather is not appreciated in a scientific point of view. The most prominent one would appear to be found in the circumstance that the influence of the moon on the weather has always been looked for in relation to the phases, whereas it should have been referred to the moon’s position with regard to the equator. The climate of British Guiana is probably the most equable in the world. The- greater part of the colony being quite flat, there is nothing to interrupt the free course of the winds, which blow for most of the year from an E.N.E. direction. The chief atmospheric disturbances take place at the solstices, those at other periods of the year being of a more temporary nature ; they must be greatly modified by the state of the atmosphere in adjacent countries. The country being in seven degrees of north latitude, is in the zone of the trade-winds for most part of the year ; and having the broad expanse of the Atlantic before it, the changes of the weather are rendered comparatively mild and gradual. British Guiana is peculiarly adapted for meteorological research, not only as rela- ting to its own climate, but as favourable for the elucidation of delicate meteorologi- cal questions, which would render valuable aid to the prosecution of the science in other quarters of the world. 54 REPORT—1859. TaBue No. 5.—Showing the Excess or Defect of Rain between those periods when the Moon’s motion in Declination is changing, and when it is greatest, or when the Moon is in greatest Declination and crossing the Equator. Moon’s Excess Defect Yearly | ail fig es | Defect. al eh = dail fib in. in. in. in. im. as, |{ S| San | ago | gee | cl [pe 1847. {3 Mas [bee booplesn (ecak } % ris, 1 S| es | gas | ane | ot |p veto. |{ | shoo | isan | wot | San |} re50. |{ S| oat | Sar | iis | wo |pee 1850s ADs cla Repo apg de Bt ool aR ae ell MMe iotan bein) bear of Slee 1893, 11 3° | ges | S00 | sae | 77 |p 8 vest. |{ S| Sor | ages | ot | aon |p 88 uss. {S| Bat | Tea | or | bee |} 8 On Thunder-storms. By G. J. Symons. On the Reduction of Periodical Variations of Underground Temperature, with applications to the Edinburgh Observations. By Prof. W. Tuomson, LL.D. F.R.S. The principle followed in the reductions which form the subject of this commu- nication may be briefly stated thus :— The varying temperature during a year, shown by any one of the underground thermometers on an average for a series of years, is expressed by the ordinary method in a trigonometrical series of terms representing simple harmonic variations *,—the first having a year for its period, the second a half-year, the third a third part of a year, and soon. The yearly term of the series is dealt with separately for the ther- mometers at the different depths, the half-yearly term also separately, and so on, each term being treated as if the simple periodic variation which it represents were the sole variation experienced. The elements into which the whole variation is thus analysed are examined so as to test their agreement with the elementary formule by which Fourier expressed the periodic variations of temperature in a bar protected from lateral conduction, and experiencing a simple harmonic variation of temperature at one end, or in an infinite solid experiencing at every point of an infinite plane through it a variation of temperature according to the same elementary law. In any locality in which the surface of the earth is sensibly plane and uniform all round to distances amounting at least to considerable multiples of the depth of the lowest thermometer, and in which the conducting power of the soil or rock below the sur- face is perfectly uniform to like distances round and below the thermometers, this theory must necessarily be found in excessively close agreement with the observed results. The comparison which is made in the investigations now brought forward must be regarded, therefore, not as a test of the correctness of a theory which has mathematical certainty, but as a means of finding how much the law of propagation of heat into the soil is affected by the very notable deviations from the assumed con- * By a simple harmonic variation is meant a variation in proportion to the height of a point which moves uniformly in a vertical circle. TRANSACTIONS OF THE SECTIONS. 55 ditions of uniformity as to surface, or by possible inequalities of underground con- ductivity existing in the localities of observation. When those conditions of unifor- mity are perfectly fulfilled both by the surface and by the substance below it, the law of variation in the interior produced by a simple harmonic variation of tempera- ture at the surface, as investigated by Fourier, may be stated in general terms in the three following propositions :— (1) The temperature at every interior point varies according to the simple harnionic law, in a period retarded by an equal interval of time, and with an amplitude diminished in one and the same proportion, for all equal additions of depth. (2) The absolute measure in ratio of arc to radius, for the retar- dation of phase, is equal to the diminution of the Napierian logarithm of the ampli- tude; and each of these, reckoned per unit of length as to augmentation distance from the surface, is equal to the square root of the quotient obtained by dividing the product of the ratio of the circumference of a circle to its diameter, into the thermal capacity of a unit of bulk of the solid, by the thermal conductivity of the same esti- mated for the period of the variation as unity of time. (3) For different periods, the retardations of phase, measured each in terms of a whole period, and the diminutions of the logarithm of the amplitude, all reckoned per unit of depth, are inversely pro- portional to the square roots of the periods. The first series of observations examined by the method thus described were those instituted by Professor Forbes, and conducted under his superintendence during five years, in three localities of Edinburgh and the immediate neighbourhood: (1) the trap rock of Calton Hill; (2) the sand below the soil of the Experimental Gardens ; and (3) the sandstone of Craigleith Quarry. In each place there were, besides a surface thermometer, four thermometers at the depths of 3, 6, 12, and 24 French feet respectively. The diminution in the amplitude, and the retardation of phase in going downwards, have been determined for the annual, for the half-yearly, third- yearly, and the quarterly term, on the average for these five years for each locality. The same has been determined for the average of twelve years of observation, conti- nued on Calton Hill by the staff of the Royal Edinburgh Observatory. The following results with reference to the annual harmonic term are selected for example :— Average of five years, 1837 to 1842. : Retardation of pha: Diminuti f Na- “Baer ae amy ht foot of descent. descent. ‘oot of descent. Calton Hill. 3 feet to 6 feet. Saas ‘11635 *12625 Goins 12) as thas ‘11344 *12156 LA 7 cavers ‘11490 "10959 DVTGUIN ais a aelars) Siac 13% days. “1149 “11914 Experimental Gardens. 3 feet to 6 feet. Nee ‘11635 ‘10037 Lite en eae has *11929 *11304 Eee yet D4 | ap aus 10617 ‘10844 Mean. ...7.. Makai 13+ days. ‘11314 *10728 Craigleith Quarry. 3 feet to 6 feet. a40% ‘063995 09372 On) ose a waa ‘066903 ‘06304 1 Ee eet Be PP Rie ‘066903 ‘06476 Mean ..... were 7X days. 065934 ‘07384 56 REPORT—1859, If Fourier’s conditions of uniformity, stated above, were fulfilled strictly, the num- bers shown in the second column would be all equal among one another, and equal to those in the third column. The differences between the actual numbers are sur- prisingly small, but are so consistent that they cannot be attributed to errors of observation. It is possible they may be due to a want of perfect agreement in the values of a degree on the different thermometric scales ; but it seems more probable that they represent true discrepancies from theory, and’ are therefore excessively in- teresting, and possibly of high importance with a view to estimating the effects of inequalities of surface and of interior conductivity. The final means of the numbers in the second and third columns are, for Calton Hill . . . . ~. - °11702 Experimental Gardens. . . ‘11061 Craigleith Quarry . . . . *06988 The thermal capacities of specimens of the trap rock, the sand, and the sandstone of the three localities were, at the request of Professor Forbes, measured by Regnault, and found to be respectively *5283, °3006, and °4623. Hence, according to position (3), stated above, the thermal conductivities are as follows :— Trap rock of Calton Hill. . . . . 121°2 Sand of Experimental Gardens . . 77°19 Sandstone of Craigleith Quarry. . . 273°6 These numbers do not differ much from those given by Professor Forbes, who for the first time derived determinations of thermal conductivity in absolute measure from observations of terrestrial temperature. In consequence of the peculiar mode of reduction followed in the present investigation, it may be assumed that the esti- mates of conductivity now given are closer approximations to the truth. ‘To reduce to the English foot as unit of length, we must multiply by the square of 1°06575; to reduce, further, to the quantity of heat required to raise 1 lb. of water by 1° as unit of heat, we must multiply by 66°447 ; and lastly, to reduce to a day as unit of time, we must divide by 3654. We thus find the following results :— Trap rock of Calton Hill. . . . . 23°5 Sand of Experimental Gardens. . . 15°0 Sandstone of Craigleith Quarry. . . 53°5 These numbers show the quantities of heat per square foot conducted in a day through a layer of the material 1 foot thick, kept with its two surfaces at a difference of temperature of 1 degree,—the unit of heat being, for instance, the quantity required to raise 1000 bls. of water by ;,5;th of a degree in temperature. On the Establishment of Thermometric Stations on Mont Blane. By Professor Tynpauu, F.R.S. I proposed to the Royal Suciety some months ago to establish a series of stations between the top and the bottom of Mont Blanc, znd to place suitable thermometers at each of them. The Council of the Society thought it right to place a sum of money at my disposal for the purchase of instruments and the payment of guides; while I agreed to devote a portion of my vacation to the execution of the project. At Cha- mouni I had a number of wooden piles prepared, each of them shod with iron, to facilitate the driving of it into the snow. The one intended for the summit was 12 feet long and 3 inches square; the others, each 10 feet long, were intended for five stations between the top of the mountain and the bottom of the Glacier de Bossons. Each post was furnished with a small cross-piece, to which a horizontal minimum thermometer might be attached. Six-and-twenty porters were found necessary to carry all our apparatus to the Grands Mulets, whence fourteen of them were imme- diately sent back. The other twelve, with one exception, reached the summit, whence six of them were sent back. Six therefore remained. In addition to these we had three guides, Auguste Balmat being the principal one; these, with my friend Dr. TRANSACTIONS OF THE SECTIONS. 57 Frankland and myself, made up eleven persons in all. Though the main object of the Expedition was to plant the posts and fix the thermometers, I was very anxious to make some observations on the diathermancy of the lower strata of the atmosphere. I therefore arranged a series of observations with the Abbé Vueillet, of Chamouni ; he was to operate in the valley, while I observed at the summit. Our instruments were of the same kind; and in this way I hoped to determine the influence of the stratum of air interposed between the top and bottom of the mountain upon the solar radiation. Wishing to commence the observations at an early hour in the morning, I had a tent carried to the summit. It was 10 feet in diameter, and into it the whole eleven of us were packed. The north wind blew rather fiercely over the summit; but we dropped down a few yards to leeward, and thus found shelter. Throughout the night we did not suffer at all from cold, though the adjacent snow was 15° Centigrade, or 27° Fahr. below the freezing-point of water. We were all, however, indisposed. I was, indeed, unwell when I quitted Chamouni; but I fully expected to be able to cast off the indisposition during the ascent : in this, however, I was un- successful; my illness augmented during the entire period of the ascent. The wind increased in force towards morning; and as the fine snow was perfectly dry, it was driven upon us inclouds, Had no other obstacle existed, this alone would have been sufficient to render the observations on solar radiation impossible. We were there- fore obliged to limit ourselves to the principal object of the expedition—the erection of the post for the thermometers. It was sunk 6 feet in the snow, while the re- maining 6 feet were exposed to the air. A minimum thermometer was screwed firmly on to the cross-piece of the post; a maximum thermometer was screwed on beneath this, and under this again a wet and dry bulb thermometer. Two minimum thermometers were also placed in the snow; one at a depth of 6, and the other at a depth of 4 feet below the surface; these being intended to give us some infor- mation as to the depth to which the winter cold penetrates. At each of the other stations we placed a minimum thermometer in the ice or snow, and a maximum and a minimum in the air. The stations were as follows :—the summit, the Corridor, the Grand Plateau, the glacier near the Grands Mulets, and two additional between the Grands Mulets and the end of the Glacier de Bossons. We took up some rockets, to see whether the ascensivnal power or the combustion was affected by the rarity of the air. During the night, however, we were enveloped in a dense mist, which defeated our purpose. One rocket was sent up, which appeared to penetrate the mist, rising probably above it; its sparks were seen at Chamouni. Dr. Frank- land was also kind enough to undertake some experiments on combustion : six can- dies were chosen at Chamouni, and carefully weighed, All of them were permitted to burn for one hour at the top; and were again weighed when we returned to Cha- mouni. They were afterwards permitted to burn an hour below. Rejecting one candle, which gave a somewhat anomalous result, we found that the quantity con- sumed at the top was, within the limits of error, the same as that consumed at the bottom. This result surprised us all the more, inasmuch as the light of the candles appeared to be much feebler at the top than at the bottom of the mountain. The explosion of a pistol was sensibly weaker at the top than at a low level. The short- ness of the sound was remarkable; but it bore no resemblance to the sound of a cracker, to which, in acoustic treatises, it is usually compared. It resembled more the sound produced by the expulsion of a cork fr-m a champagne-bottle, but it was much louder. The sunrise from the summit exceeded in magnificence anything that fT had previously seen. The snows on one side of the mountain were of a pure blue, being illuminated by the reflected light of the sky ; the summit and the sunward face of the mountain, on the contrary, were red, from the transmitted light ; and the con- trast of both was finer than I can describe. I may add, in conclusion, that the lowest temperature at the summit of the Jardin during last winter was 21° Cent. below zero. We vainly endeavoured to find a thermometer which had been placed upon the sum- mit of Mont Blanc last year. 58 REPORT—1859. GENERAL PHYSICS. A Proposal of a General Mechanical Theory of Physics. By J. 8. Stuart Gienniz, IA. The approach of a planet to a sun, iron to a magnet, one particle to another, may be the effect of, or conceivable only as the effect of a pull of the sun, the magnet, or the first particle ; but such a pull, however useful as a temporary metaphysical, or metaphorical conception, is mechanically an absurdity : such approach can be mecha- nically conceived only as the movement of the planet, the iron, or the second particle in the direction of least pressure as between the sun, the magnet, or the first particle, and some third body. A somewhat extensive colligation of physical facts has led to the conviction that, by further experimental and mathematical research, attractions and repulsions will be found explicable as expressions of the relations of the pressures between three bodies, a general mechanical theory of physics established, and thus the ‘‘ persuasion” of Mr. Faraday and the profoundest scientific thinkers, “ that all the forces of nature are mutually dependent, having one common origin, or rather being differeut mani- festations of one fundamental power,”’ demonstrated as a truth. The mechanical conceptions and explanations of phenomena with diffidence offered in this paper, are as yet given, less as a theory, than as a proposal of a way in whicha general mechanical theory may be established. And the following is a summary of, perhaps, the principal of these conceptions and modes of explanation. Atoms are conceived as mutually determining centres of pressure. Thus, atoms are not conceived as particles in a medium or in space, at distances from each other determined by the proportions of the hypothetical forces of attraction and repulsion, but as in contact with, and pressing against each other, while their centres are at distances determined by relations of inward and outward pressure. For convenience of representation and mathematical calculation, atoms may also be defined as centres of lines of pressure; the comparative length of these lines being taken to represent, not the absolute, but the relative development of the force of the atom. Matter, or that which resists our force, is conceived as a form of force; and the idea of force is explained by the conceptions of— Equilibrium—the state of equality among the opposing pressures of a system of atoms (defined as above) or bodies (defined as aggregates of atoms). Motion—the effect of a difference of polar pressures on an atom or body; deter- mined in direction by the resultant of greatest pressure; in degree (or velocity) by the ratio of such difference ; and as uniformly accelerated, varyingly accelerated, or uniform, according as that ratio is constant, varyingly, or uniformly inconstant. A line of motion—the direction of the transmission of pressure relatively in- creased at one point, and correspondingly decreased at all others. Heat and specific heat—the former is conceived as an expression of the relations of the mutual pressures of bodies,—the latter, of atoms. The solid, liquid, and gaseous states appear deducible from certain conditions of relative pressure between three bodies or atoms. From the condition of equal transmission in all directions, it follows that, in a system with that condition, an increased pressure in any direction will be, as it were, broken up; hence the ratio of resistance at any point will be greater than if the pressure had been directly transmitted ; it will be radially transmitted; and will diminish according to the law of the inverse squares. The phenomena of static electricity appear explicable as the results of the pressure on each other of heterogeneous bodies, or bodies of less and greater power of resist- ing pressure. Hence the outward pressure of the one is increased, of the other diminished ; and hence positively and negatively electrified balls may be represented, the former as having its own, the latter the lines of pressure of the medium increased. The poles of dynamic electricity are the ends of a line of motion,—points of greater and less pressure. The relation of magnetism and electricity is the mechanical consequence in a medium of the lateral diminution of pressure increased at a point. Conduction and insulation, magnetism and diamagnetism are corresponding TRANSACTIONS OF THE SECTIONS. 59 antitheses, expressive, under different conditions, of the phenomena resulting from greater or less resistance to the transmission of increased pressure, The gravitation of any two bodies to each other is attempted to he mathematically explained as the mechanical consequence of the relations of the mutual pressures of the two bodies, and the resistances of the medium or other bodies. The undulations of light, &c. appear as the consequence in a medium of certain different relations of the outward pressure of two bodies, Polarization is considered as the condition ofa line of motion in relation to a mechanically conceived medium. In electrics, we study the different relations of the ends; in optics and thermotics, of the sides, of a line of motion. The problem proposed by this theory for mathematical solution is—what are the conditions of pressure and resistance to its transmission that would produce such and such effects? And this theory would direct experiment to the comparison of the different resistances of bodies to different conditions of increased or diminished pressure. On the Philosophy of Physics. By Joun G. Macvicar, D.D. The object of this communication is to simplify our first steps in physics, by di- minishing the number of considerations which at present stand in the position of independent data or postulates; and more especially, to show that the all-important properties of inertia, elasticity, and gravitation, instead of being unrelated, as is ge- nerally supposed, do in reality form a group of properties which imply each other, and are in fact nothing else but uniform phenomena resulting from one and the same law, according as that law is viewed in reference to the substance cr the form of a single element of matter, or in reference to a system of such elements distributed in space. In order to reach this law, the author commences by rejecting from thought all the specific properties of individual objects, so as to be left in possession of that which is common toall. He thus finds Substance or Being; of which he prefers the latter term, as being positive and even absolute in its import, and therefore suitable to build science upon, oreover, in the very term itself he finds the law, of which inertia, elasticity, and gravitation are the expressions and the results. Thus the term Be-ing implies that the subject of it both exists and (excluding at present the consideration of living, self-changing Beings or Spirits) continues to be as itis. Now this, expressed dynamically so as to give a physical law, implies ¢hat which both exists and has the power of repeating its existing state in every successive moment of its existence; or as may be said, that which both exists and assimilates itself to itself in successive moments of its existence (and that without limitation, and therefore) through the whole sphere of itsagency, and thus assimilates other beings or things within that sphere, more or less, as well as itself. Whence obviously two grand func- tions are implied in the operation of this law : first, Self-assimilation, implying the per- manency of the type of the species, be it chemical element, crystal, plant, or animal; and secondly, Mutual assimilation, implying the phenomena of Induction, Generic resem- blance among species, and general Harmonyinnature. This law the author regards as the impress of the immutability and unity of the Creator in his works. And though there is often (perhaps always) a mechanical apparatus by which it is worked out in nature, yet it may, if found true, be accepted during our ignorance of that apparatus, as a rational explanation of phenomena for which he holds that its relevancy is para- mount. Inertia.—Under the law that has just been laid down this property immediately appears. ‘Thus, given a physical point, unit of matter, atom, or element of mere being, the law of Being (which from its mode of action may also be called the law of assimi- lation) calls upon that clement to continue to be, nay, to be as it has been and is now, _to repeat its existing state, to assimilate itself to itself in every successive moment of itsbeing. And therefore if it be at rest, it must continue at rest, unable to leave the place in which it is but through some force applied to it from without. If, again, it be in motion, that is, continually leaving one point in space for the next point adjacent to it, that also it must continue to do in every successive moment of its existence. From which it follows, that not only is the perpetuity of the motion secured, but the form of it is determined. Thus a translation from one point in space to the next 60 REPORT—1859. point adjacent, is an element of a straight line necessarily lying in some definite direction. But to this, under the law, every successive element of motion must be assimilated. The whole therefore, when viewed in reference to space, must be recti- linear. And for the same reason, when viewed in reference to time, it is obvious that equal portions must be described in equal times. The whole motion therefore must be uniform as well as rectilinear. Elasticilty.— But whatever possesses substance and can be distinguished from the space in which it exists, must also possess form. And in reference to this attribute, the law of Being or assimilation obviously providesthat a form once constituted in harmony with that law shall tend to perpetuate itself, shall tend to assimilate itself to itself in successive moments of its existence, and consequently, if partially disturbed, shall make an effort to recover its form and volume, in other words, shall be resilient or elastic. Thus elasticity, instead of being wholly unconnected with inertia, presents itself under our law as the inertia of form. And here it admits of being shown that the form of culmination under this law, towards which every other form must tend, and which all forms do attain when there is nothing in their internal structure or position in nature or their history to preveut its development, is the spherical shell or cell. Gravitation. But mere beings or things, units of matter or atoms, which, when viewed as individuals under the Law of Being or assimilation, prove to be inert and elastic, must also, when existing as a system under this law, gravitate towards each other; for, as has been stated in the announcement of the law, it is universal and reciprocal. And hence two or more atoms being given within the sphere of each other’s agency, but at a distance from each other, it follows that each, while maintaining itself to the utmost, must also tend to assimilate to itself to the utmost all the others around it. Now, although in virtue of the first function of this law (which is to maintain the specific character, the type, in the individual), the amount of mutual assimilation effected in any given case may not be great, in so far as the form and structure of the different members of the system are concerned, and such that they manifest themselves only after leng eras, or in some phenomenon of transient induction only, yet there is no bar in the way of their being assimilated, as to the place they occupy, except the inertia of the system. Each member in that system will therefore tend to assimilate all the other members of the system to itself in this respect, thatis, to draw or attract them all into its own place, and consequently to itself. And this each must obviously do with a force proportional to itself, that is, to its quantity of being or substance or mass; for of material things we know nothing, and can conceive nothing but as localized, individualized, limited forces, or aggregations of force, more or less. All the members in a system which exist within the sphere of their mutual agency, must therefore attract each other proportionally to their masses. Nor is this all the light which our law throws upon the grand phenomenon of gravitation. It also determines the force of gravitation at different distances from the centre. Thus, conceiving it geometrically and mechanically, which is indispensable when our object is to obtain a geometrical and mechanical expression, we are obliged, under the law of assimilation (as is indeed commonly done under every hypothesis), to conceive of the attractive force of any centre as existing around that centre in concentric spherical shells, their radii and surfaces continually increasing as they recede from the centre. Now these spherical shells, in order to satisfy the law of assimilation, must be all assimilated to each other in the amount of attractive force which they represent; they must be all dynamically equivalent to each other, be they large and remote from the centre of force, or small and near that centre. But if so, it plainly follows, that, when estimated in any one direction or along any one radius, the force must diminish as the spherical surface or the square of its radius increases. But this is the well-known law of gravitation. Thus the three great properties of matter, inertia, elasticity, and gravitation, show themselves to be intimately and beautifully related, not arbitrarily conjoined, and. such that a single conception explains them all. TRANSACTIONS OF THE SECTIONS. 61 INSTRUMENTS, &c. On producing the Idea of Distance in the Stereoscope. By Josrru Beck. In a view taken through the camera no immediate foreground can be introduced : thus we lose in the photograph an important element in nature for the appreciation of size and distance. In reproducing nature we ought to supply some substitute. This can easily be accomplished. Take an ordinary glass transparent view, and look carefully at it; in some instances the foreground absolutely appears to project into the instrument; and never is it so arranged that the idea of the distance of the fore- ground of the picture from the edge of the stereoscope is given. Take now a black mat or card, with two holes so cut in it, that:when laid on the view, the right eye can see more of the left-hand side of the right picture, and the left eye can see more of the right-hand side of the left picture. It will then be obvious that the excentricity of this mat will indicate a difference of angle; and in proportion as this excentricity is increased or decreased, so the picture appears to advance or recede from the stereo- scope; and as the view recedes and distance is given, so the appearance of the real size of nature is obtained. If the plan is reversed, and the mat is cut so that the right eye sees less of the left- hand side of the right picture than the left eye, we can produce the appearance of the object standing up in the instrument, and in proportion as it approaches the stereo- scope, so the size is decreased. In these cases there is no difference in the angle at which the pictures are taken, and yet such vast differences in the apparent size of the picture, showing that whilst the amount of difference of angle is a matter of compa- ratively but little consequence, the introduction of a prominent foreground, such as mentioned above, enables us to estimate the real size of the object viewed. The carrying out of this plan may be observed in the mounting of Mr. Warren dela Rue’s photographs of the moon. Had they been mounted in the centre of circles, they would have appeared as 2-inch balls with beautiful miniature volcanoes and mountain ranges traced upon the surface; but when mounted excentrically, they immediately appear as floating far off in space, every hill and valley, mountain, volcano, or plain assuming grand and imposing dimensions. On the Stereoscopic Angle. By A. CiAuvet, F.R.S. On the Stereomonoscope. By A. Ciaupet, F.R.S. On the Focus of Olject-Glasses. By A. Ciaupet, F.R.S. The researches on this question tended to show the relation between the distances and sizes of objects with the focal distances and sizes of their images, and to find the two points, one before the lens and another behind, from which the distance of ob- jects and the focal distances must be measured, and from which all proportions are in an exact ratio ; for it is found that measuring from the object-glass on both sides, double distance of object does not produce one-half of the focal distance, and vice versd. These two points are, first, the point before the lens which produces an image infinitely large at infinite distance ; and behind the lens, the point which is the focus for an object at infinite distance, giving an image infinitely small; it is obvious that these two points are on each side the zero of the scale of measure, and it re- mained to fix the position of another point before the lens, which produces behind the lens an image as large as nature. The two spaces between these points, one in front and the other behind the lens, are perfectly equal, and they are each the unit by which all distances of objects and all focal distances are to be measured. Double the unit in front will give a focus one-half of the unit behind the lens, and one-half of the unit in front will give a focal distance double of the unit behind the lens, and all the other distances in the same proportion; so that, knowing either the distance in front of the lens, or the focal distance, the other distance can be found without having to examine the focus on the ground-glass ; the only thing to do being to divide the scale called “ the unit of focal distances,” in any number of parts corresponding in an inverted ratio with the progression of distances in front of the glass, 62 REPORT—1859. - On a Changing Diaphragm for Double Achromatic Combinations. By A. CLaupet, F.R.S. Mr. Claudet explained the construction of his contrivance, intended to reduce or increase the aperture of a double achromatic lens without having to unscrew one of the lenses and without any slit on the tube. This is done by two rings revolving on one another, like the top and bottom parts of a round snuff-box, and each carrying a number of india-rubber stripes, the other end of which was attached on the opposite ring ; so that making the ring not fixed in the tube to revolve by an external pinion, the india-rubber stripes were drawn intermixing each other, gradually reducing the aperture until each of them was extendiug on the diameter of the tube, on which disposition the whole aperture was shut. Mr. Claudet exhibited also the very in- genious pupil diaphragm, invented by Mr. Maugey, optician in Paris. On an Instrument for exhibiting the Motions of Saturn's Rings. By Professor J. Ckerk Maxwe t. The author exhibited an instrument made by Messrs. Smith and Ramage of Aber- deen, to exhibit the motion of a ring of satellites about a central body, as investi- gated in his ‘ Essay on the Motion of Saturn’s Ring.’ It is there shown that a solid or fluid ring will be broken up, and that the fragments will continue in the form of a ring if certain conditions are fulfilled. The instrument exhibits the motion of these fragments as deduced from the mathematical theory. On a New Photometer. By the Abbé Moreno. The Abbé said that the instrument could be applied to determine the intensity of the light of the fixed stars, and even of the several parts of the surface of the sun. On a New Electro-Medical Apparatus. By M. RuumKorrr, exhibited and explained by the Abbé Motcno. The Abbé briefly described Daniel’s, and Grove’s and Bunsen’s galvanic batteries, the chief objection to the two latter being the evolution of nitrous acid fumes. The peculiarity of the instrument he exhibited was, that sulphate of mercury in solution contained in two neat little cups of carbon was used to excite the zinc ; a small bat- tery of two cells, aided by a Ruhmkorff’s coil, packed up in a small box, constituted the apparatus. On Becquerel’s Phosphoroscope. By the Abbé Moteno. On the Phonautograph, an Instrument for registering Simple and Compound Sounds. By the Abbé Moreno. The Phonautograph is an instrument which consists of a large chamber or drum, of a spheroidal form, with a diaphragm or drum-head at one end, which, by a system of levers, works a pen to record the sounds which the form of the cham- ber causes it to concentrate on the tympanum. The Abbé exhibited a drawing to the Section, which explained the construction of the instrument, and then ex- hibited drawings showing the actual markings of the pen over a sheet of paper car- ried past it by clockwork ;—I1st, when tuning-forks sounding various notes were vibrated in presence of the instrument ; 2nd, when several notes were sounded on a diapason pipe; and 3rd, when a person spoke before it. In the first two cases, the recording pen drew such regular curves, that the number of vibrations corresponding to the note as seconds could be counted, and, as the Astronomer Royal observed, they were obviously the curve of sines. In the case of the human voice, the words spoken were written below the corresponding tracings of the pen; and although these were very irregular, yet a marked correspondence could be traced, especially where the words contained 7, g, and other well-marked low or guttural sounds. Portable Apparatus for Analysing Light. By M. Porno. This instrument was a telescope, at the side of which the light to be analysed TRANSACTIONS OF THE SECTIONS. 63 could be introduced by a slit, and being then reflected down, met a prism of flint- glass, with its remote side silvered, and placed perpendicularly to the axis of the observing or telescopic part ; the light then reflected back is dispersed as if by a prism of double the refracting angle of the prism of the instrument, and the dispersion is then measured by a micrometer placed at the focus of the eyepiece. On an Improvement in the Proportional Compass. By Lieut.-Colonel R. SHorrrepe. This consists in the introduction of two moveable discs, on which alone the friction takes place, so as to avoid the unequal rubbing of the jaws. This is mischievous, as the jaws invariably become striated circularly at the points of usual setting. Under this unequal action of the jaws they are very apt to shift their position, while at the same time it is very difficult to alter the adjustment by a small quantity when re- quired. These objections have almost thrown the proportional compass out of common use as an instrument for exact work. On a New Photographic Lens, which gives Images entirely free from Distortion. By Tuomas Surron, B.A. The author described a combination by which the effects of distortion are totally obviated, and which gives an image that is mathematically perfect. The conditions for obtaining an image free from distortion are these :— ist. The axis of every pencil must emerge from the combination in a direction parallel to that of incidence. 2nd. The axis of every pencil must pass through a certain fixed point. 3rd. The image of every luminous point of the object must be formed at the point where the axis of the pencil meets the focusing screen. The combination is a Symmetrical Triplet, consisting of two equal achromatic plano-convex lenses, one at each end of a tube, placed with its convex side outwards, and a small double concave lens of equal radii placed exactly midway between them. In contact with the double concave lens a small stop is placed. It is evident that in this combination a small oblique pencil is incident excentrically upon the front convex lens,—that its axis after suffering deviation passes centrically through the concave lens without suffering further deviation, and that it is then incident excentrically upon the posterior convex lens, from which it emerges in a direction parallel to that of incidence. The above is true of every oblique pencil, and their axes all pass through a common point, which is the centre of the Symmetrical Combination, and which point is called C. The Ist and 2nd conditions are therefore fulfilled. The proof that the 3rd condition is also fulfilled is as follows :— The focus of an oblique pencil is in every optical instrument a disc of light, and not an exact point. The size of this disc is reduced by using a small stop. When it is sufficiently reduced, by using a sufficiently small stop the focus upon the screen is said to be good. In that state the ray which passes through C (the axis of the pencil) is one of the rays which compose the small disc or good focus, because C is at the centre of the stop. The focus is therefore at the point where the axis of the pencil meets the focusing screen ; and therefore the 3rd condition is fulfilled. By a fortunate circumstance this Triplet gives an image which is equally illu- minated in every part, because the area or base of the oblique excentrical pencil upon the front lens is greater than that of the direct central pencil, and in this way the loss of light from obliquity is counteracted. Spherical aberration in the direct central pencil is totally corrected, because the negative aberration of the concave lens counteracts the positive aberration of the convex lenses. There is consequently brilliant definition in the centre. At the same time, the marginal definition is as good and the field as flat as that of any lens now in use. In order to get good marginal definition and the proper flatness of field, the distance between the convex lenses should be about one-sixth of their focal length, and the 64 REPORT—1859. focus of the concave lens should bear to that of the convex lenses the ratio of about 13:8. On the Angular Measurement of the Picture in Painting. By H.R. Twrntne. The angle subtended by a picture changes as it is removed further from, or brought nearer to, the observer ; and by this change in its position the relation of the near objects to the distant ones becomes altered; so that they cannot be equally correct in both positions of the picture. By means of a small instrument, which may be termed the Hand-goniometer, the student is enabled to fix approximately the di- stances of objects as represented in a picture, especially in subjects where linear perspective is little concerned. The span given to the two arms of the goniometer fixes the proximity of the picture, by assigning a given number of degrees (about 50) to its apparent width, and thus ensures a conformity between the objects there depicted, and the natural subject which they represent. The nearest point of the foreground in a level scene averages about 10 yards from the observer, corresponding to an angle of 10° below the horizon; but when the observer is situated above the general level of the prospect, the picture extends down- wards to a greater angle below the horizon, so as to include a larger area, or receding plane, between it and the ground line. Figures would generally appear too large if introduced on the very ground line; the size of the nearest usually corresponds with the proportion of human figures at about 15 yards off, corresponding to about 7° from the horizon downwards. The relation of many other points to the horizontal line may be obtained in a similar manner. A matter of some interest, for marine painters, is the amount of depression of the visible horizon or sea boundary caused by the convexity of the earth ; for although a subject of minute inquiry in an artistic point of view, yet it is just sufficiently appre- ciable to be worth the artist’s consideration ; since erroneous drawing, with respect to it, may be observed in many of the pictures of coast scenery ; a greater amount of dip of the horizon being accounted for by the concealment of objects behind it, than is consistent with truth. Sir John Herschel, in his ‘ Outlines of Astronomy,’ observes “ that two points, each 10 feet above the surface, cease to be visible from each other over still water, and, in average atmospheric circumstances, at a distance of about eight miles;”’ which limits the horizon of the sea, to an observer’s eye situated 10 fect above its level, to a distance of four miles, and assigns to it, at that distance, a real depression of 10 feet only. With the aid ofa glass, the effects of so small an amount of depression become easily appreciable on the sea-side. From the shore, at Eastbourne, I could discern only the sails of a large vessel, which may have been ten miles distant; whereas, from an eminence of about 60 feet above low water, I could distinctly see, with the aid of a telescope, the entire hull, which probably rose 15 feet above the water. But a vessel situated at that distance scarcely measures an angle appreciable to the unassisted eye, and therefore becomes too minute an object to be safely represented in a picture, as partially hidden by the sea’s boundary line; in fact, this natural effect could only be introduced in very minute art representations. It is true, the extremely foreshortened appearances presented by the sea’s surface, to an individual on the beach, causes boats and vessels, stationed at considerable intervals from one another, to appear almost in contact, or to seem on the verge of the horizon, although really not at all remote; but this is owing entirely to the illusions of perspective, and cannot be increased to any appreciable amount by the convexity of the water’s surface, or the earth’s rotundity. But the case is somewhat different with regard to the amount of depression of the visible horizon, as considered in connexion with the existence of mountains on the coast. The elevation of Beachy Head, amounting I believe to 700 feet above the sea, suffices to cause a depression of the visible horizon, which appeared to me appreciable with the aid of this imperfect instrument; and although this small amount of the horizon’s dip does not affect the pictorial character of the sea-view, «which from such a position is remarkable for its vast expanse both horizontally TRANSACTIONS OF THE SECTIONS. .65 and vertically), yet the convexity of the sea exercises an influence on the outline of very distant mountains which are seen beyond the horizon; for these do not exhibit as they approach the horizontal line any kind of break or change in the direction of their slopes, as is usually observed in the forms of mountains which fall down to the visible edge of the water, but their characteristic curves are cut off, as it were, mid- way by the line of the horizon which conceals the sea-worn base of each mountain. CHEMISTRY. Address by Dr. Lyon Puayrarr, £.R.S., President of the Section. My predecessor in this chair, Sir John Herschel, drew our attention to the great im- portance of studying, with increased accuracy, the combining proportions of bodies in the hope of determining the exact numerical relations which prevail between the ele- ments. He justly regarded it as a subject worthy of the most accurate experiment, to ascertain whether the combining proportion of the Elements are multiples of the combining number of hydrogen, as suggested by Prout; cautioning chemists at the same time not to accept mere approximative accordances as evidence of this relation. I have now to congratulate the Section on the publication of the laborious investigations of Dumas on this important inquiry. It required a chemist of great manipulative skill, as well as of fertile experiment, to obtain combining numbers for the elements upon which a greater reliance could be placed than upon those determined with such admirable precision by Berzelius, that great master of analysis. The atomic weights found by that chemist did not, for many of the simple bodies, confirm the suggestion of Prout as to the multiple rela- tions of these numbers to the equivalent of hydrogen. At the same time the more re- cent determinations for the atomic weights of Carbon, Silver, and some other elements, so closely coincided with this view, that it was very desirable to extend new experi- ments to the bodies which had fractional atomic weights assigned to them. In M. Dumas’ memoirs there are the results, though not the details, of a large series of experiments on many of the elements. He obtained numbers of precisely the same value as those of the Swedish philosopher when he followed his methods of analysis— numbers which are not the multiple of the equivalent of hydrogen. But when he pur- sued his experiments upon these same elements, with the new methods of discovery and his own inyentiveness, then atomic weights were obtained which corrected them- selves from the error inherent in former methods of analysis, and resulted in being multiples of the combining proportions of hydrogen, or in standing in a very simple relation to that number, ‘There is on this point evidence so clear that there is scarcely a chance of deception. The labours of Dumas, Schneider, Marignac, Pierre, Peligot, and others, have esta- blished the relation by recent determinations of chlorine, iodine, bromine, silver, tita- nium, &c.,—elements differing so much in chemical character as well as in atomic weight, that it is difficult to conceive any fortuitous combinations which could have produced such uniformities in the results of analysis. Hence the general view of Prout, that the equivalents of the elements, compared with certain unities, are represented by whole numbers, seems to be established by recent experiment, although it would be premature to declare that there are no exceptions to the law. We are familiar with many inge- nious discussions on the natural grouping of the elements, and the relations of their equivalent numbers to each other. I allude to the papers of Gladstone, Odling, and Mercer, and to the views of Cook, in America, Although these efforts point to im- portant dependences of the elements on each other, we cannot yet adopt them as parts of our scientific system. Another question of a different character, as regards equiva- lents, has recently received attention. I refer to the proposal to double the equiva- lents of carbon and oxygen, that is, to raise them from 6 and 8, to 12 and 16 respect- ively. As these two elements are essentially connected with the whole system of chemistry, the right determination of their equivalents is a matter of extreme import- ance, Undoubtedly there are cogent reasons which induce many of our able chemists 1859. 7 5 66 REPORT—1859. to double the equivaients of carbon and oxygen, and they are well worthy of the calm and deliberate consideration of a meeting like this. Such an alteration would produce an immense change in the literature of the science, and should only be adopted if the benefit to be derived from it proved to be so great as to justify the inconvenience. This subject will be brought before the Section on more than one occasion. ‘The change proposed has, in a great measure, resulted from the new views of the classification of organic compounds introduced by Ger- hardt. The recent brilliant progress in organic chemistry has resulted in the dis- covery of a vast number of new compounds. A scheme of classification became urgently necessary for them, and the genius of that great French chemist pro- duced a system which has exerted a most important influence on the advancement of science. The comprehensive system planted by Gerhardt has been carefully watered and tended by our countrymen Williamson, Hunt, Odling, and Brodie— until the young plant has attained a most vigorous gtowth. In a report upon the state of organic chemistry, by one of these gentlemen, we shall have the advan- tage of tracing its effect on the advance of science. Another of our members who admires the beauty of the plant, and the excellence of the fruit it has borne, fears that it is growing too wildly, and that the pruning-knife might be adopted with ad- vantage. He therefore proposes for our consideration, in a paper which will be laid before you, some modifications of the system of classifying compounds now so preva- lent. With the array of talent in our Section, enlisted in favour of Gerhardt’s system, there will be full justice rendered to the merits of that lamented philosopher in any discussion which may follow the reading of the paper to which I allude. In conclu- sion, I have to congratulate the Meeting upon the important muster of English che- mists in our Section; although we have at the same time to regret that our cold northern position has prevented our foreign colleagues from joining us, and enjoying aa welcome which the warm hearts of our countrymen would assuredly have accorded to them. On the Solubility of Bone-earth from various Sources in Solutions of Chloride of Ammonium and Common Salt. By Mr. Binney. On Pentethyl-stibene. By G.B. Bucxton, F.R.S., F.C.S. This paper detailed the preparation of a new organo-metal compounded of one equivalent of antimony and five of ethyl. The author stated that great difficulties presented themselves in isolating the new body, from the tendency it showed to split by distillation into ethyl and triethyl-stibene. In this decomposition it imitates the de- portment of pentachloride of antimony, which by heat evolves chlorine. The existence of this substance, the author conceived, had some importance, since it confirmed the views lately advanced by some chemists, that the ethyl compounds of antimony and of arsenic form no exceptional cases, but are most naturally referred to the types of antimonious and antimonie acids, &c. On the Specifie Gravities of Alloys. By F. Crace CAtvert,; Ph.D., FLRS., FCS. &¢., and Ricuarp Jounson, F.C.S. &e: The study of alloys and amalgams having been made especially with impure or commercial metals, the results obtained have been such that it has been impossible to solve the important question, Are alloys and’ amalgams chemical mixtures or com- pounds? It is with the hope of throwing some light on this subject that we have for the last two years been engaged in examining, comparatively, some of the physical ‘properties, such as the conductibility of heat, tenacity, hardness, and expansion of alloys and amalgams made with pure metals, and in multiple and equivalent quantities as follows :— : 1 Copper and 1 Tin 1 Tin and 2 Copper 1 »” 3 2 ” 1 ” ” ” 1 ” » 3 5 and 1 1 ” » © 5, 1 = 1 ” » 5 5 : ey By this method we have succeeded in ascertaining, first, the influence which each additional quantity of a metal exerts on another ; secondly, the alloys which are coms we ~ + TRANSACTIONS OF THE SECTIONS. 67 pounds and those which are simple mixtures; for compounds have special and cha- racteristic properties, whilst mixtures participate in the properties of the bodies com- posing them. ‘This method of investigating alloys and amalgamshas enabled us to ascer- tain the metals which combine together to form definite compounds, and those which, when melted together, only form mixtures. Thus, for example, bronze alloys are defi- nite compounds, for each alloy has a special conductibility of heat. -Thus the alloy— Obtained. Calculated*. Difference, Sn Ci? seisscsisiaisie. §=18°65 19°87 6:22 GBn'Cw® viscescsiais..cs 15°75 21°37 5°62 Sri Cii* ssisssssssscssccss = 4°96 21:88 16°92 SHOW sssssscesss dsstssa G0 22°50 15:90 These same alloys have a specific gravity of their own. Thus— Obtained. § Calculated*. Difference. Soi Wl" sacocacsh cance cas 8-533 8°059 0°474 NHOUS stttatacs casssecs 4 8:954 8208 0°756 MCUs ccscsccess ap entin 8-948 8306 0:642 Su Cue® ...4. tibasacecasds 8-965 8°374 0°591 The same fact is also observed in the expansion or contraction of these alloys; whilst, on the contrary, the alloys of tin and zinc being mixtures, conduct heat, have a specific gravity, and expand according to theory, or the proportion of tin and zine which they contain. Thus for heat— Obtained. Calculated. Difference. SUA a sassescavevcnat’ 15°15 14°90 0°25 VATS mee Radgaave deldcs 16°00 15°80 0°10 Zn? Sn visiss. Nictseses .. 16°65 16°95 0°30 Specific Gravity. Obtained. Calculated. Difference. WANS”. veccsceee sess eetee ne 7193 0-081 ATS Meteora bees ysheeet 7262 77134 0°128 Pn? Sti versie pasbeceer 7°188 7-060 0°128 The authors then gave tables showing the specific gravity of variotis alloys and amalgams divided under two heads :— I, Those which have a higher specific gravity than indicated by theory, Of this class there were five series, viz. copper and tin, copper and zinc, copper and bismuth, copper and antimony, and tin and zinc,—comprising thirty-one alloys. If, Those which have a less specific gravity, or expand. Of these there ate six series, viz. mercury and tin, mercury and bismuth, mercury and zine, antimony ah bismuth, bismuth and zine, and tin and lead,—comprising forty alloys and amalgaiiis. Their researches reveal two important facts; first, that there is one metal the alloys of which always contract, viz. those of copper, whilst all the amalganis éx- pand or have a less specific gravity; secondly, that the maximum expansion or con- traction of alloys and amalgams generally occurs in those which are composed of oneé eqitivalent of each metal, the exception being those of tin and zinc. But this atises no doubt from the fact, that all the alloys, with the exception of the latter, are comi- pounds and not mixtures. In conclusion, attention is drawn to the extraordinary contraction or expansion that some of these alloys experience. Thus, for example, the alloy of three of copper and one of tin, Found. Calculated. Difference. 8954 8-208 0°746 whilst the amalgams of tin expand to nearly the same extent, as shown by thesé results :— Found. Calculated. Difference. sai ae le eA 10°255 11-259 1-004 * The principle upon which the theoretical conductibility, specific gravity, and expansion are calculated, is similar to that followed with respect to hardness, for which; seé Philoso- phical Transactions, 1858. 5* 68 REPORT—1859. On the different Points of Fusion to be observed in the Constituents of Granite. By M.F. BraLLtosiorzxy. On the Formation of Rosolate of Lime on Cotton Fabrics in Hot Climates. By F. Crace Catvert, PA.D., F.RS., F.CS. The author exhibited some picces of calico which were covered with red stains, and he stated that a short time previously the cargoes of two ships on arrival in India had been found to be extensively damaged by these stains. After a great number of experi- ments he had found those stains to be due to rosolate of lime, the formation of which he traced to the following cause. Amongst the packing or materials used to surround the bales and protect them from wet and injury, was a kind of waterproof felt made of corded cotton bound together and strengthened by a layer of gutta percha which had been dissolved in impure coal naphtha, the cloth thus made having been then pressed between cylinders. Under the influence of the warm and damp atmosphere of India, the hydrate of oxide of phenyle, or carbolic acid, became volatilized, and coming in contact with the carbonate of lime contained in the calico, was transformed into rosolate of lime. The correctness of this result was proved by enclosing pieces of white calico.in bottles with pieces of the felt, the calico being uppermost; and also by placing a little carbolic acid at the bottom of the bottles instead of the felt, the bottles being kept at a temperature of 110° Fahr. for several days, when in both instances the calico exhibited red stains identical with those which he had previously found in the goods returned from India. On Crystallized Bichromate of Strontia. By Dr. DALzELL. On the Economical Preparation of Pure Ohromic Acid. By Dr. DAuzeELt. Dr. Dalzell having experimented on large quantities of material, recommends as the result of his investigation, the process of Traube for the production of the impure acid and its perfect purification by from four to seven recrystallizations, and com- pression of the products between large porous tiles. He describes the modifications in colour and density which chromic acid presents, according to the process by which it has been prepared. Before applying the baryta test for its purity, Dr. Dalzell reduces with alcohol and nitric, not hydrochloric acid; and he states that when the solution of sesquioxide was diluted, twelve hours at least should be allowed for the action of the test before the purity of the product was affirmed. Dr, Dalzell also proposes bichromate of strontia as a means of obtaining pure chro- mic acid. He gave the particulars of the process for obtaining the strontia salt of absolute purity from carbonate of strontia and commercial chromic acid. Bichromate of strontia crystallizes with three atoms of water, all of which it loses at 212° Fahr. He has obtained from it pure crystallized neutral and acid chromates of many of the metals by employing equivalents of their soluble sulphates. Dr. Dalzell gave the particulars of the composition of several of the metallic chro- mates; and referring to the action of bichromate of potash on a solution of chloride of barium, stated that when the temperature of the liquid is raised to the boiling-point, Peligot’s salt is abundantly formed. He recommends this as the best method for preparing the bichromate of the chloride of potassium. The author stated that he was at present engaged in further researches on the crystallized chromates. Dr. Dauseny exhibited specimens of several varieties of Volcanic Tufa from the neighbourhood of Rome and Naples, Reports from the Laboratory at Marburg. By Dr. Gururin. TRANSACTIONS OF THE SECTIONS. 69 On the Fluorescence and Phosphoreseence of Diamonds. By J. H. Guapstone, Ph.D. P.RS., FCS. While examining the remarkable chromatic properties of Prof. Way’s mercurio- electric light, the author observed, that of four diamonds on a ring, two were beauti- fully fluorescent, one slightly so, and the remaining one perfectly unaffected in that manner. Some other diamonds were found to exhibit the same phenomenon in this light, though the majority did not. The fluorescence resembled that of bisulphate of quinine, and was produced by the same rays, so that the interposition of a solution of quinine stopped the power of the light to produce this effect. The same two diamonds were found to be fluorescent by the lightning flash, On exposing the ring to the sun and bringing it into a dark place, it was ascertained that the two most fluorescent diamonds were very phosphorescent, and the slightly fluorescent one slightly phos- phorescent, while the fourth exhibited neither phenomenon. On examining the long paper of M. Becquerel on phosphorescent substances, published just previously in the * Annales de Chimie et de Physique’, it was found that he had obtained somewhat similar results; the diamond, however, is a difficulty for M. Becquerel, as it forms an exception to the rule that “the fluorescence produced is always of the same shade as the phosphorescence.” In like manner with the ring in question, while the fluor- escence is blue, the phosphorescent tint is a greenish white, scarcely resolved by the prism, but by the action of absorbent media appearing to be between D and E of the solar spectrum. No blue was observable, even the moment after exposure to the sunshine. Red or yellow glass interposed between the sun and the diamonds prevented the phosphorescence, while blue glass, similarly interposed, gave rise toa brilliant display, suggesting the idea that the less refrangible rays of the spectrum are positively anta- gonistic to this power; yet the diamonds become phosphorescent when exposed to the light of a candle. On one occasion, when exposed to the sun’s rays through cobalt blue glass, they shone visibly when removed merely into dim daylight. On another occasion, after simple exposure to the sun, they were observed to emit light for an hour and a quarter. If this phosphorescence be the continuous result of some molecular change wrought on the diamond by light, it would appear probable that the effect would go on increa- sing with the amount of exposure, at any rate, up to some saturation point. This is no doubt true to a certain extent; but in endeavouring to reach this point, the author found that a long exposure to sunshine diminishes the phosphorescent power of the diamonds. This did not seem to be due to differences in the atmosphere or tempe- rature, or to any diminution of the power of the eye to perceive the phosphorescent light, but to be a property inherent in the stone itself. The effect is a very marked one; and what is specially remarkable, is that the diamond which has thus almost lost the power of phosphorescing is found the next day as sensitive as ever. On Photographs of Fluorescent Substances. By J. H. Guapstone, Ph.D. PRS. FCS. It is well known, on the one hand, that the chemical action of light resides mainly in the most refrangible rays, and, on the other hand, that these rays are altered in their refrangibility and effect on the visual organs by fluorescent substances. It occurred to the author that such substances would probably exert little photographic action. Hence he had made two drawings on sheets of white paper, one in an acid salt of quinine, the other in a very pale solution of chlorophyll, and had taken photo- graphs of them. Although the drawing in quinine was quite undistinguishable from the white paper, and the chlorophyll drawing nearly so, when they were viewed in the camera for adjusting the focus, they were strongly marked on the photographic image by the little chemical action that had been exerted by them. The sheets of paper, and the drawings developed on the glass plates, were exhibited, showing that what theory had suggested as probable was true in fact. On a New Form of Instantaneous Generator of Illuminating Gas by means of Superheated Aqueous Vapour and any Hydrocarburet whatever. By MM. Isoarp and Son. The apparatus in question for transforming aqueous vapour into illuminating gas, 70 REPORT—1859. consists of a steam-boiler without reserveir, into which a very small quantity of vapour is injected every second by means of a small hand-pump, or by a force borrowed from the generator itself. This water, on descending through a serpentine tube, heated to redness, becomes spontaneously reduced to vapour almost in a state of decomposition, in which state the two gases, oxygen and hydrogen, are at the limit of combination and separation. At the place where, and at the moment when this vapour, under a pressure of from seven to eight atmospheres, is about to leave the serpentine tube, a determinate and proportional quantity of mineral pitch, heavy pit oil (huile lourde de houille), coal-tar, turpentine, or any other hydrocarburetted liquid is injected by a contrivance exactly similar to that by which water was introduced into the boiler. The superheated aqueous vapour and the hydrocarburet at the moment of contact give rise to a series of decompositions and recompositions, into the theory of which we shall not at present enter; the result, however, is the transformation of all the gases contained in the water and hydrocarburet into illuminating gas, This gas next passes into a purifier, where, at the same time, it becomes compressed by several atmospheres; on issuing from the purifier, it is collected in the usual manner in a gasometer, whence it may be distributed at pleasure. M. Jacobi of St. Petersburg and M.1’Abbé Moigno, who witnessed the experiment, could at first scarcely believe the testimony of their own eyes, though they were compelled ultimately to admit that the small apparatus just described generated per minute almost 1500 litres (53 cubic feet) of very rich gas, which burned with mar- vellous facility, and produced a very intense white light. We have here literally fire and light extracted from water. By a simple calculation it may be shown that the quantity of heat contained, theoretically, in the gas furnished by the above apparatus is many times greater than the quantity in the charcoal burned in the furnace; so that if the generated gas were conducted by suitable tubes into the furnace, the generation of gas might be prolonged indefinitely, even though, at the same time, a notable quantity were reserved for ex- ternal purposes of heating and illuminating, It is scarcely necessary to remark that this is no case of perpetual motion, for the generation of gas only continues so long as water is injected into the serpentine tube and a hydrocarburet through the orifice of this tube. Now the water and the hydrocarburet possess the force stored up in the latent state, and this force, in order to become vis viva, requires a mechanical effort which brings together the vapour and the hydrocarburet. The illuminating gas thus produced, which is four times as rich as that used at Paris, would not cost a centime per cubic metre (one-tenth of a penny per cubic yard), so that the method would introduce a vast improvement in the economic production of light and heat. In applying the method on a large scale, it is true some difficulties would have to be overcome; the relative quantities of injected water and hydrocar- buret would require to be determined experimentally for each hydrocarburet, and kept perfectly constant during the process of alimentation, Again in transporting the gas to a distance by means of pipes above or below ground, care would be neces- sary in order to prevent decomposition and loss of carbon or richness ; but the experi- ments already made to this end are perfectly satisfactory. Ox the Effects of different Manures on the Composition of the Mixed Herb- age of Meadow-land. By J. B. Lawes, F.R.S., F.C.S., and J. H. Gu- BERT, PA.D., F.C.S. Under what might be called the system of concentrated production, more prevalent in this country than elsewhere, the arable land of a farm was, of course, subject to the loss of those mineral constituents which were contained in the corn, and in the meat, that were sold from it. Those of the straw of the corn-crops, and by far the larger proportion of those of the roofand green-crops generally, were, for the most part, returned tothe arable land. “But, in addition to this return, the meadow-land attached to the arable farm frequently contributed to the manure applied to the rotation-crops. Moreover, under the system of high farming, cattle-food, and also special or artificial manures, containing certain mineral constituents, will be purchased, and thus enrich the stores of the arable land, It thus happens, that the arable land, under good ordi- TRANSACTIONS OF THE SECTIONS. 71 nary management, if it do not already produce the maximum average crops which the seasons will allow, will probably require the additional use of nitrogenous rather than mineral manures, to bring its yield up to that point. It is somewhat different with the meadow-land of the arable farm. Not only is the amount of mineral constituents removed from a given area of land in an ordinary crop of hay, much greater than that contained in what may be called, so to speak, a corresponding grain-crop, but the proportion of the mineral constituents which will be returned to the land by the home manures in the case of the meadow, will generally be very much less than in that of the corn-land. It is very important, therefore, to study the effects of different characteristic mar nures, both on the amount, and on the composition, of the meadow-hay crop*, It was found, that mineral manures alone increased the total produce of hay, in the case of the experiments in question ; but that they caused the increased develop- ment of the highly nitrogenous Leguminous plants, almost exclusively—the Grami- naceous ones appearing to be scarcely benefited at all. .4mmoniacal salts, on the other hand, increased the growth of the less nitrogenous Graminaceous plants, almost to the exclusion of the Leguminous. The increase by either manure, used separately, was, however, comparatively very limited, But, by the combination of both mineral manure and ammoniacal salts, an increase of about 2 tons of hay had been obtained annually, for several consecutive years; and the produce was almost exclusively Graminaceous, It contained, in fact, not 5 per cent. of Leguminous and Weedy herbage put together. The kinds of the Grasses themselves, which were developed, also varied very much according to the manure employed. The proportion of culm-bearing flower or seed, and of leafy produce, respectively, likewise varied very remarkably. From the above facts it would be expected, that the chemical composition of the mixed produce—or hay, would be very much affected by the manures employed. Such, in fact, was the case. The percentages of nitrogen, of impure fatty matter extracted by ether, and of cellular matter or ‘ woody-fibre”—and, of course, of the complementary substances—varied very much. And, looking at the composition in connexion with the known conditions and characters of growth, it was concluded that in such green and unripened produce, high percentages of nitrogen, and of crude fatty matter, were indications of low condition of elaboration, and of comparatively low feeding capacity. Turning to the composition of the ash of the hay, it was found that the percentages of potash, and of phosphoric acid, were very much increased by supplying these sub- stances in manure. The amounts of these constituents, taken from a given area in the crop, were also very much increased by such supply. The acreage amount of silica—a constituent which had not been supplied in the artificial manures—did not increase commensurately. This was the case, notwithstanding that, not only were the larger crops very prominently Graminaceous, but the Graminaceous produce itself was in large proportion stemmy. Where hay was grown for the supply of a neighbouring town, the supply of the necessary mineral—or soi/-proper—constituents, was generally fully maintained by town manures of some kind brought by return carriage. But, where hay was grown on an arable farm, and mown for consumption by stock, or, still worse, for sale, the return was but too often by no means so complete. It was, indeed, highly desirable that the meadow-land attached to the arable farm should receive a fairer share of the home manures, than was usually, or at least frequently, the case. ‘This was the most efficient, and the most economical means, of keeping up the mineral supplies of the meadow-land at such a point as to allow the growth of the maximum crops which the seasons will allow, by means of specially nitrogenous manures. Without the latter, indeed, little or no increase of the Graminaccous produce can be anticipated; whilst, it is by means of such produce, that we must hope to get, in the long run, our largest crops. ‘The question of keeping up the fertility of grass-land by means of sewage, or * For a detailed account of their results, see— Report of Experiments with different Manures on Permanent Meadow-land,” by the Authors, in the Journal of the Royal Agricul- tural Society of England, as follows :—“ Part I.—Produce of Hay per acre,” vol. xix. part 2; “Part I1.—Produce of Constituents per acre,” and ‘“ Part J1J.—Description of Plants deve- loped by different Manures,” vol. xx. part-1 ; and “ Part [V.—Chemical Composition of the Hay,” vol. xx. part 2.- : 72 REPORT—1859. other irrigation, was, of course, entirely separate from the one here under considera- tion. So far as the chemical composition of hay was concerned, it appeared that—the more the produce was Graminaceous, the more it went to flower and seed ; and the more it was ripened, the higher would be the percentage of dry substance in the hay. Under the same circumstances, the higher will be the percentage of comparatively indurated, and therefore probably effete, cellular or woody matter—and the lower will be that of the total crude nitrogenous compounds, of the impure green fatty matter, and of the mineral matter, in the dry substance. On the other hand, a large proportion of non- Graminaceous herbage, over luxuriance, succulence, a large proportion of leaf, and unripeness, were likely to be associated with a small proportion of the more refractory cellular or woody matter, but with a large one of nitrogenous substance in a questionable degree of elaboration, a large one of impure fatty matter of doubtful nutritive capacity, and a large one also of mineral matter, in the dry substance of the hay. From the results of the investigation as a whole, it appeared, that the proportion, and the relative feeding value, of the various chemical compounds of which the complex substance—hay—was made up, depended on such a multiplicity of cireum- stances, that, even supposing there were no question as to the proper relationship to one another of the different elaborated compounds in our stock-foods, it would still be impracticable to get a true and unconditional estimate of comparative feeding value of such crude vegetable produce, by the simple determination of the percentage amount of one or two important constituents, as was frequently assumed to be suffi- cient for that purpose. The next step in advance in such inquiries could only be attained, when our knowledge of the proximate compounds—of lower or of higher condition of elaboration—into which the ultimate constituents of our food-stuffs were grouped, had been much extended; and when the digestibility, and applicability to the purposes of the system, of the various proximate compounds, had been experi- mentally determined. On the Analysis and Valuation of Manures. By 8. Macavam, Ph.D. F.CS. On the Organic Molecules and their relations to each other, and to the Medium of Light, illustrated by Models according to the Author's Theory of the Forms and Structures of the Molecules of Bodies. By the Rev. Joun G. Macvicar, D.D. An analogy of function in the entire series of chemical agents being admitted, it follows that an analogy of structure is to be looked for; and the author of this com- munication, building upon this principle, proceeded to unfold his theory, which infers that what has been proved of a vast number of molecules is true of them all; and that whether in the actual state of analysis they be decomposable or not, they are all com- pound and constituted each of its own peculiar group of lesser atoms, the ultimate atom being the same in all, It is not hydrogen, however, that the author looks to as the mother element or ultimate atom, and that which would be obtained from all bodies in the last analysis, if such analysis were possible ; not only because such hypothesis is excluded by the fact (which meantime must be respected) that the atomic weights even of some of the most abundant molecular agents in nature (chlorine for instance) are not multiples of that of hydrogen, but yet more, because nature herself presents another element, one with which all space is filled, and whose position in nature is such, that, analogically viewed, it seems the common vapour of all bodies considered as mere matter, viz. the particles of light or of the ether, respecting the existence of which there can be no doubt, as every ray of light (not to speak of the retardations and tails of comets) demonstrates. The principle on which the author conducts the synthesis of these particles into permanent groups, representing, according to his theory, the molecules of bodies, is that of statical equilibrium or balance of mutual attractions and repulsions, which, however, is always one and the same with the principle of symmetry. And thus, as the first symmetrical species, the first that possesses a single axis terminated by poles. TRANSACTIONS OF THE SECTIONS. 73 which are similar to each other (which demand two atoms), and an equator giving a plane at right angles to the poles (which demand three at least), he obtains a group of five as ‘he nucleus of the first molecular species to be looked for in the laboratory— the nucleus, for the volume of the molecule is supposed to be determined by an elec- tric and calorific atmosphere, which invests the constituent atoms to a great extent, and which tends ever to be of a spheroidal form, whatever the form of the nucleus. Now it appears a priori, that is, when viewing this first molecular body of five ele- mentary atoms purely in reference to its own structure and to the medium of light in which it is conceived to exist, that it must possess the following properties:—Ist. In the fully insulated or individualized state, that is, the aériform, it must be the lightest of all gases; for it follows from a law which the author communicated to the Physical Section, that equal volumes of different gases are to be expected to contain equal num- bers of molecules, or numbers in a simple ratio to each other. 2ndly. It must be pre- eminently elastic; for where there is no loss of heat, we can only suppose a defect in elasticity in a gas to be caused by what we know to cause such defect in other cases, viz. violence done by the compression or strain of the elastic structure. Now of this molecule the structure is the simplest and most stable possible. More than any others, therefore, it is secure from strain, and it may therefore be expected to be eminently elastic under the greatest pressures, 3rdly. It must in relation to its quantity of matter be the most highly refractive and reflective of all molecules; for it is well known and is demonstrated by all aériforms, that it is between similars that the most intense re- pulsion takes place. Now this molecule is more similar to the medium of light than any other, its every element consisting of a single particle. Between it and light there will therefore be a maximum repulsion, that is, a maximum reflexion or refraction, as the case may be. 4thly. If, therefore, it be viewed as in the solid state, this molecule would be of a metallic nature, and it may be expected to perform the functions of a metal. Now these are the well-known properties of the first of the laboratory gases so well known by the name of hydrogen, But there is this difference between these pro- perties as obtained experimentally and as deduced from the author’s theory. In the former case they are obtained only as so many individual facts with regard to hydro- gen, which are empirically or incidentally coexistent in the same body. In the latter they are seen to coexist rationally, to imply each other, and in fact to be expressions, in different points of view, of one and the same structure. Assuming this simplest of insulable ‘molecules to represent hydrogen, its atomic number and weight is of course 5, from which there results, happily for the author’s theory, a remarkable coincidence between the current atomic weights on the hydro- gen scale and those which this theory gives, not as conventional like the other, but representative of absolute structure. Thus the tendency in the present day, as it was long ago, is to regard the weight of hydrogen as one-sixteenth of that of oxygen, one- twelfth of that of carbon, &c., and therefore representable by -5 instead of 1°0, as has been usual. Hence the current tables become adapted to that which this theory re- quires; simply by moving the decimal point one degree to the right. The equivalent of H being *5, that of O from 8:0 becomes 80, that of C from 6:0 becomes 60, and so on; care being taken, however, to distinguish well between equivalents and atomic weights, since the equivalent of active elements, whose place is usually on the poles of a central body, consists of two atoms at least, else symmetry of structure in a single equivalent of the compound is impossible. It is chiefly in reference to the chemical functions of molecules, however, that this theory shows its value and its power. This was shown in reference to hydrogen in its relations to carbon, of which latter the genesis and model were next exhibited ; and which proved to be a five-sided obtuse bipyramid composed of 30 particles of light, as hydrogen is a three-sided acute bipyramid; both viewed in reference to tangent planes. Thus the model of an atom of carbon shows seven regions for the attachment of other bodies, one on each pole, and five on the equator. Charge it fully with atoms of the simplest possible hydrocarbon, viz. CH, and we obtain C+-C,H,= C,H,. Now on inspecting works of experimental chemistry, this is seen to be the formula of caoutchouc, the most highly charged hydrocarbon which tropical vegeta- tion alone supplies, In this molecule the nucleus is an atom of carbon; but nature delights in inver- sion; as by inverting the vegetable she gives the animal kingdom. Let us take an 74 ‘ REPORT—1859, atom of hydrogen as the nucleus, and charge it similarly with CH. In this case an atom of C being added to each pole, the axis is CH in a double sense, viz. CHC, one atom of H performing the functions of two, But vow as to the equator, instead of five regions of union, as there were in the case of carbon, there are only three ; whence the fully charged molecule which we obtain in this case is CHC+C,H,=C,H,. Now this, chemistry gives as the elementary formula of the non-oxygenated essential oils (usually written C,,H,,, out of respect to the four-volume theory, but betraying its tetratomic character by the 4HO which appear in the camphors, &c.). And so on with a multitude of hydrocarbons. This synthesis gives them; and they are found to be eminent in nature in proportion as their construction is easy and symmetrical in this theory. But let oxygen play a part. The first atoms of carbon which must go off from the hydrocarbon C, H,, must be those of the equator. Now these are, as has been stated, three in number, leaving C,H,—C,=C,H,, a beautifully constructed and balanced molecule, leading us to expect it abundantly in nature. And there it is abundant, being the formula of marsh-gas. Most interesting also are its chemical functions being a very stable nucleus, Thus add to each pole an element of syrup (simple hydrate of carbon, CHO, which in the molecular form determined by the pentagonal form of C, requiring as it does the dodecahedron, gives C,,H,,0,,), and instead of marsh-gas we have alcohol. Instead of an element of syrup, add to each pole (of C,H,) one of carbonic acid, CO,, or one equivalent C, O,, and instead of alcohol we obtain acetic acid, Add carbonic oxide instead, and we obtain aldehyde; and going into regions where nitrogen abounds, instead of carbonic oxide add nitrous oxide, and we obtain urea, NO+C,H,+ NO=C,H,N,0,, and so on. And here the doctrine of substitution beautifully presents itself; thus in C,H,, or C,HH,, there are three atoms of H which are appendages to the equator, and can obviously cede their places to chlorine, &c. without any destruction of symmetry. Hence, instead of C,HH,, we may have C,HCl,=chloroform. Instead of aldehyde, C,HH,0,, we may have C,HC],0,=chloral. Instead of acetic acid, C,HH,O,, we may have C,HCl,0,=chloracetic acid, &c. The relation of urea and uric acid (considered as monobasic) also appears, and the therapeutic problem assumes a definite form. Thus instead of urea, C, HH,N,O,, we have C,HC,N,O,=C,HN.O, uric acid, and so on, the substitutions being often easy and such as nature suggests, while the series of the chemist are too often expressive rather of what is possible to nature than what is natural, On the Action of Air on Alkaline Arsenites. By J. M°DoNNELL. On Corne and Demeaux’s Disinfecting and Deodorizing Powder. By the Abbé Moieno, On Matches without Phosphorus or Poison. By the Abbé Moreno. The Abbé Moreno exhibited a Nephelogene capable of being adapted to many Chemical, Therapeutic, and Hygienic purposes. New Process of Preserving Milk perfectly pure in the Natural State, without any Chemical Agent. By the Abbé Moteno. To preserve milk for an indefinite period is an important problem, which in France has been solved in three different modes. M. de Villeneuve was the first to preserve milk, solidifying it by the addition of certain solid ingredients, but it was no longer, properly speaking, milk. M. de Signac preserved it by evaporating the milk till it became of the consistence of syrup, rendering it a solid mixture of milk and sugar; still it could not be called milk. M. Maben also preserved it by excluding the air, and exposing it to an atmosphere of steam about 100° Cent——thus depriving it of all the gases which it contained, and then hermetically sealing the filled bottles in which it had been heated. When about to leave for Aberdeen, I opened a bottle which had been closed by M. Maben on the 14th of February, 1854; and after a lapse of five years and a half, [ found it as fresh as it was the first day. M. de Pierre has greatly TRANSACTIONS OF THE SECTIONS. 75 improved the discovery. The means which he employs to effect the preservation of milk is still heat; but heat applied in some peculiar way, by manual dexterity, first discovered by a Swiss shepherd. All that I am allowed to state is that the effect of this new method of applying heat is to remove a sort of diustore, or animal ferment, which exists in milk in a very small quantity, and which is the real cause of its speedy decomposition. When this species of ferment is removed, milk can be pre- served for an indefinite period of time in vessels not quite full, and consequently exposed to the contact of rarefied air, a result which was not effected by the process of M. Maben, or rather that of M. Gay-Lussac, as they completely expelled those gases which otherwise would have rendered it sour. I have such full confidence in the success of M. de Pierre’s process, that I had not the least hesitation in bringing along with me from Paris to Aberdeen a large vessel containing five gallons of milk, fearlessly trusting it to railroads and steam-boats, thus exposing it to all the incidents of the journey. Iam so confident of the success of the process, that I pour out the contents of this large vessel into Scotch glasses with the conviction that I am giving to the ladies and gentlemen of the British Association a milk as natural, as pure, and as rich as when it was taken from the cow in the fertile plains of Normandy. May this potion, so sweet and so pure, be a symbol of those sentiments of benevolent affection, which France, flourishing and enlightened, entertains towards her noble and great sister England! Owing to its greater specific lightness cream ascends to the top of. the vessel, but it can be easily made to diffuse itself through the milk by slightly shaking it before uncorking the bottle. As the vessel is not quite full, a small quantity of butter may have been formed, and the milk may have become somewhat less rich, but it will still be pure and natural milk without any strange taste. ‘Thanks to the progress of science, of which I am happy to be the representative, France ean yield with profit to England her fruits, her vegetables, her eggs, and now offers her prepared milk for the wants of the army and navy, having nothing to fear from the longest voyages, nor from the excesses of heat and cold. Quantitative Estimation of Tannin in some Tanning Materials. By Messrs, Mutiican and Dow ine, On Marsh's Test for Arsenic. By W. Ovuine, V.B., F.RS., FCS. Marsh’s test depends upon the production of arseniuretted hydrogen when arsenical substances are in presence of nascent hydrogen. The author showed that numerous and varied bodies, including animal tissue, vegetable tissue, the organic matter contained in ordinary earth, preparations of copper and mercury, and oxidi- zing salts, prevented the formation of arseniuretted hydrogen, and thereby defeated the action of Marsh’s test. As a mode of separating the arsenic from these interfering substances, the author recommended the process of distillation with muriatic acid, whereby arsenic in the form of terchloride of arsenic is isolated in a form suitable for testing by Marsh’s process, On the Composition of Thames Waiter. By W. Ovuine, M.B., F.R.S., and A. Duprt, Ph.D. F.CS. The general conclusions were as follows :—The amount of dissolved matter, organic and mineral, is greater in high than in low water, in consequence of the contamination of the high water with sea~water—greater in summer than in winter, in consequence of the greater contamination with sea-water in that season, dependent upon the dimi- nished volume of the fresh stream-water. In the winter and early spring, when the quantity of stream-water is great, the presence of sea-water scarcely makes itself felt in the high water, even at Greenwich ; or, in other words, there is very little difference in the saline matter of low and high water; but in dry weather this difference becomes more and more marked, and is noticeable higher and higher up the river. Early in the present year, the existence of sea-water in the river was very perceptible, so much so, that even at Wandsworth a difference between high and low water was observed, comparable to that which existed at Greenwich during the winter months. During gorresponding periods, the ayerage amounts of residue in high and low water at 76 REPORT—1859. Lambeth, were found to be about half as much as the average residues yielded by high and low water at Greenwich respectively, ‘The summer averages at Lambeth cor- responded very closely with the winter and spring averages at Greenwich. ‘Lhe per- centage amount of suspended matter in the river was found to be twice as great at low as at high water. At low water at Lambeth, the amount of dissolved matter, mineral and organic, is greater at the sides than in the middle, showing that the pure stream-water cuts for itself a central passage through the foul stagnant water at the sides. The same action, though in a much less marked degree, takes place at high water. The up-cast flow, largely contaminated with sea-water, forces for itself a central passage through the stagnant sides, Another point of interest was the differ- ence in composition between the surface water and the deep water. During the flow, the sea-water runs up underneath the river water, and although a complete mixture of the two layers eventually takes place, yet a difference of composition between the top and bottom layers may occasionally be recognized as high up as the Thames Tunnel. The effect produced upon the quality of Thames water by a heavy rain-fall was also illustrated. On a New Mode of Bread-making. By W.Ov.ine, U.B., FBS, FCS. The vesicular character of ordinary bread results, as is well known, from the development of carbonic acid gas uniformly throughout a mass of fermenting dough, whereby a loose spongy texture is imparted to what would otherwise be a dense sod- den lump of baked flour and water. In fermented bread the carbonic acid gas, generated within the substance of the dough, isa product of the degradation of certain constituents of the flour, namely the starch and sugar. In Dr. Dauglish’s newly invented process, the carbonic acid gas is produced independently and superadded to the flour, which consequently undergoes no degradation whatever. Carbonic acid, stored in an ordinary gas-holder, is pumped therefrom into a cylindrical vessel of water, whereby the water becomes charged with the gas. This carbonic acid water is mixed, under a pressure of 100 lbs. on the square inch, with the flour, and the resulting dough, which becomes vesicular on the removal of the pressure, is divided into loaves, and baked in a travelling oven. The advantages of the new process are :—Ist. Its cleanliness. Instead of the dough being mixed with naked arms or feet, the bread, from the first wetting of the flour to the completion of the baking, is not even touched by any one. 2nd. Its rapidity, An hour and a half serves for the complete con- version of a sack of flour into baked two-pound loaves. 3rd. Its saving of Jabour and health. It substitutes machine labour for manual labour of a very exhausting and unhealthful character. 4th. Its economy. Despite the heavy prime cost of the apparatus, yet the use of carbonic acid is found to be cheaper than that of yeast, Moreover the waste of the saccharine constituents of the flour, necessary in the old process, is avoided in the new one. 5th. Its preventing any deterioration of the flour. In making fermented bread from certain varieties of flour, the prolonged action of warmth and moisture induces a change of the starchy matter of the flour into dextrine, whereby the bread becomes sodden and dark-coloured. This change is usually prevented by the addition of alum ; but in operating by the new process, there is no time for this change to take place, and consequently no advantage in the use of alum. 6th. The character of the bread. Chemical analysis shows that the flour has undergone less deterioration in bread made by the new than in that made by the old process. The bread has been tried dietetically at Guy’s Hospital and by many London physicians, and has been very highly approved of. On some New Cases of Phosphorescence by Heat. By Dr. T. L. Pureson, of Paris. Some years ago M. Scheenbein showed that metallic arsenic becomes phospho- rescent when its temperature is raised to a certain degree. Lately, M. Linnemann remarked that potassium and sodium were phosphorescent in the dark when freshly cut. The phenomenon is doubtless owing to the rapid oxidation of these metals when exposed to the air. The light emitted by sodium is greenish yellow, that of otassium is of a redder tint. I have had occasion to examine sodium whilst phos- phorescent; its light is very feeble, and is only seen upon the surface freshly cut with TRANSACTIONS OF THE SECTIONS, 77 a knife, and exposed to the air, This phosphoric light, like that of potassium, lasts for a few minutes only at the ordinary temperature of the atmosphere ; but at a tem- perature of about +70° (Centigrade), the light emitted by sodium nearly equals that given out by phosphorus itself, I have lately observed also that copper, native sulphuret of copper, and silver are notably phosphorescent by heat, With copper the fact is most striking. In order to observe the phenomenon, one or two grammes of copper should be melted before the blowpipe in a cavity made in a piece of charcoal. Assoon as the copper is thoroughly melted (at the inner flame) it glows with a greenish yellow phosphoric light, similar to that of the glow-worm. On cooling a little it rapidly loses this property, and at the same time a molecular change is observed on the surface of the metal. Native sulphuret of copper (Chalkosine) is likewise phosphorescent when melted before the blowpipe. Silver becomes slightly phosphorescent only for an instant on cooling, just before it leaves the liquid state. I have found also that the mineral Lepidolite is quite as phosphorescent by heat as fluor-spar. But to see this phenomenon perfectly, it should be viewed through a piece of glass coloured blue by oxide of cobalt. When seen in these circumstances, the phosphoric light of Lepidolite is very fine; and, when seen through the cobait glass, the phosphorescence of fluor-spar is far more brilliant than when observed with the naked eye. This mode of experimentation is probably applicable to all substances that are phosphorescent by heat, Composition of the Shell of Cardium edule (Common Cockle). By Dr. T. L. Purrson, of Paris. The specimens analysed were taken on the coast of Ostend (Belgium). The best of five analyses gives for their composition :— Water ...... Rslaengeroctecn sean ranaarstcanccomoncssraesetie LALO ONpaAnICMALLety cenecnatas'ss dass eanases-sc=teasccparssasp beak Carbonate of lime....cec.seseees Roneneeusees Sadeasteness 92°93 Phosphate of lime........sss0..008 anacancbee ss seiivepenen [OL Sulphate’ of lime” ci. v.1sscccseseaaene nawelscuire sph see O84 Magnesia ......00004. teennceee aenashieressasisasies' seocese O13 Beroxade’of trowc.:ecsesscs