THE ‘ANNALS PHILOSOPHY. NEW SERIES. |» JANUARY TO JUNE, 1821.) SI a VOL. E OR THE SEVENTEENTH FROM THE COMMENCEMENT. rr aLondon : ‘Printed by C. Baldwin, New Bridge-street ; FOR BALDWIN, CRADOCK, AND JOY, -PATERNOSTER-ROW. oe ee 1821. a} oat > ql Cb diviws ‘i er £ » at 5 ae ) SLAP RIMAM OS TABLE. OF CONTENTS. NUMBER I.—JANUARY. Page On the true Atomic Weight of Strontian, Lime, Magnesia, Phosphoric Acid, and ‘Arsenic Acid. Ry Thomas Thomson, MD. FRS. . ayarara On the Geology of the Malvern Hills. By W. Phillips, FLS, MGs. ie 16, A remarkable Stratum of Limestone situated at Calder Side. (With a MUNDO A Wang deh elas bn ce als snes se espe reas nes cre st Mhete'¢ esac 23 On thi Pecticn of Chlorides and Water. “By R. Phillips, FRSE. FLS. &e. 27 ‘Extract from “ An Account of Two late Attempts to ascend Mont Blanc.” 33 Description of a new Clinometer. By S.P.Pratt. (Witha Plate,).... 43 On Red Snow. By Dr. Henderson. ...... Pe ruin Mahe p< bpihis's m8 vid 9 Aine 43 New Method of drawing a Tangent to the Circle. By Mr. Ritchie...., 4) On abe Dey Ror: Dy Mr. Dinsdaie’ sis cee cc cas yacs cts cb epscce 45 Circle Fall Gf Ratios. CARAS 8 vems es auaws some estsss 45. On Whale Oil. By Dr. Bostock. .........200.: s Rapa Sue aA de atce SG On the Preparation of pure Salts of Manganese, and on the Composition of its Oxides. “By Dr, Forchhammer, .......ceceeccceccnsecnecsceuees oe Analytical and Critical Account of The Edinburgh Pharmacopeeia. .. 58 Proceedings of the Royal Society, Nov. 23, 30, Dec. 7, and 14.......... 04 Geological Society, Nov. 3,17, Dec. 1, and 15...... 67 . Test for Barytes and Strontia.....cseeeeeeseveees (| eae Meier ues 72 Ammoniacal Alum.......... LES wEieninntacdinoleees CIE walk o's'e' piv Oe"e's''s'e oa > 72 Sulphate of Indigo as a Test to determine the Strength of Solutions of Oxymuriate of Lime ........ cc cece ee ece ere te ee eee se cer nereseceres 72 On the Application of Chromate of Lead t to Silk, Woollen, Linea; and Cotton. By M. J. L. Lassaigne. ...... eae pias apeke 7 Ra ae 93 Pligpels fo orpeustns pari taeconin se dae RT Genes ii oa oes shuns Woy on 4 New Scientific Books... .......se00e. WS cisa's's vb Nb age vy wep ea rc nce > 74 I Pata Tass cue acs Bee Gle 6 Wie SWinnice Ms Uh pine MER EME xe ae» 68 75 Col. Beaufoy’s Astronomical, Magnetical, and Meteorological Observa- Bons, for NGvemi ber. oi.) ei eed as Sas GEES CAM ees eee ee bee Nese nees 76. Mr. Howard's Meteorological Journal for November. .....+...ssseeeeee, 79 See il eae NUMBER IL—FEBRUARY. On the Mathematical Principles of eseron Philosophy. By Mr. Em- Mett (COMmbNUEM). 60. ccc di ce cec escent tees concer ere rerecseesrcseen 8 On an Apparatus for discharging ‘Ordnance. By Mr. John Deuchar. (With a Plate.). DES cack cas econereverees eteebeseces eeoevresese 89 > iv CONTENTS. Page Summary of the Magnetical and Meteorological. Observations for Three ne Years and Nine Months. By Col. Beaufoy, FRS......s..ceseeeeeees 94 On a Method of applying Maclaurin’s Theorem. By Mr. James Adams. 98 On the Solution and Crystallization of Lime. By R. Phillips, FRSE. &c. 107 On the Bicarbonate of Ammonia. By theSame............ Gala G alae wre . 110 On Rain-Guages. By Mr. Davenport..........seceeeseees covcceseove LIL On the Machine for measuring a Ship’s Way by the Log Line........... 113 On the Action of Crystallized Bodies on Homogeneous Light. By J. F. W. Herschel, Fog. FRSLL. and E. , oo. .csecscvccccesciesvsecascgesee sees pAlb Meteorological Journal kept at New Malton. By Mr. Stockton. seevceee 133 On Compressibility of Water. By P.M. Roget, MD. FRS, &c......... 135 New Substance found in Ironstone. By the Rev. J. J. Conybeare...... 136 Electro-magnetic Experiments.........c.ccccccsesccecccesse. soseevs «- 137 Analytical Account of Researches on the Magnetism of the Earth ...... 138 Analytical and Critical Account of An Essay on Chemical Analysis. ...# 140 Proceedings of the Royal Society, Jan. 18, and 25......... CREM: 144 Geological Society, Jan. 5 ....0..cceseesceee Lees 149 Crystallization of Red Oxide of Copper .........00..eeceecsceecccceece 150 Description of Two New Substances found, by Dr. Macculloch, in the Isles of Rum and Mull..........cceceee ces beb'he shivhih cnniben aches » 151 Production of Artificial Cold. ............04+ ‘Amida Sone Bass oi: sp ia 153 Mercurial Atmosphere. ...... i cian hetigcaigai ioe te Die a Eade Oa . 153 Salphouret of Chrome os3'5 i): cas asks omiesnlevcenscahe vas’ Sibewpsgcntn mt ee ‘New Scientific Books .......:.+.seecssseeees nits Mtn lide 4 ice atin naka «Le Hew Patents 6 cies. ses crakasinnnnse 7 NE ace RR MERIT FH 155 Col. Beaufoy’s Astronomical, Magnetical, and Meteorological Observa- sions for Decotbet ss 5 siting: on o08s ob cos» 05 oXeeg eit ubic epi n> «tine es 156 Mr. Howard’s Meteorological Journal for Dosate. bad Sak a beet nell »- 159 a NUMBER III.—MARCH. On the Action of Crystallized Bodies on Homogeneous Light. By J. F.W. Herschel, Esq. FRS. (continued). . (With a Plate.) ....... 161 Observations on Van Marum’s Memoir on Franklin’s Theory of Electri- Rep. CONSGER DIAC, ), oo cde des sivivcecnccnn sopenvictamehiusteetiasne 181 Remarks on Mr. Phillips's Anslysis of the Edinburgh Pharmacopeia. By BIE EAONG 4.04 nneivinn ss Vand te cbbadid (one cnchaan tie ceeieee eae oe 187 Chemical Examination of the Common Hop. By Dr. Ives, of New York 194 On various Mixtures of Oxymuriate of Potass for discharging Ordnance. . 202 Col. Beaufoy’s Magnetical and Meteorological Observations for Jan...... 203 On the Going of a Clock with a Wooden Pendulum. By Col. Beaufoy. 203 Diurnal Variation of the Magnetic Needle. Communicated by Col. SI ins wins on cece sucdesicceecnrcnsnnccenMieeeneumese: +s chum 205 Remarks regarding the Experiments upon Flame. By Mr. Deuchar.... 206 Ona Machine for measuring a’ Ship’s Way by the Log Line. By Mr. BMOWURRNG Tes meae ress. c ccc iccocececovccdeneeane se vue ceaeumnmene ++» 208 CONTENTS, a Page On the Comparative Advantages of illuminating by Gas from Oil and from Coal. By Mr. M SRicardo yay sas 'n simpson eben he vaccine 54k RORy On a peculiar Substance in Nitric Acid. By M. Jalins otiAbo sinje'e's seree 216 On the Composition of Prussiates. By Prof. Berzelius .........0000005 219 On the Compressibility of Water. By Mr. Perkins..........seseseeees 222 Analyticai and Critical Account of Dr. Paris’s Pharmacologia sPenencie se, S23 Proceedings of the Royal Society, Feb. 1, 8, 15, and 22.........+0005 227 Cambridge Philosophical Society........6..2.00005 229 Notice of some new Minerals from Finland. By M. Julin.......... ve», 233 Mining Intelligence. .........00- 2 ibaa Mika he Ani ening 4 IT Soaps See 236 New Scientific: Books? .4:..'1-. asics ss nsec ccsnae opicrige 0's wee ee oan ton 237 Dee Patents o sisians vinebs soma vette Mia Gis © a ke eMac me Reishi tele than 'on 238 Mr. Howard’s Meteorological Journal for January. ...ssssescesesseeees 239 ——— NUMBER IV.—APRIL. Experiments to determine the true Weight of the Atoms of Copper, Zinc, Iron, Manganese, Nickel, and Cobalt. By Thomas Thomson, MD. PE ios ocak REE ain SUR Oh bee a Foe RE Ain opie Cpa same hae ale eeauwe 241 Analysis of a Native Carbonate of Magician: By William Henry, MD. PU eo vets Te tape oe vr ee er ee Upevde Ceus Oh Ose rite ees eo ers Mente TNE 252 On the Red Rock Marle, or Newer Red Sandstone. By the Rev. J. J. RROD PDRRIE DEUS ai as SRSA CYTE UR AT ok Stes Se OO Pe 254 On a new Method of constructing geometrically the Cases of Spherical Triangles. By Mr. W.L. Birkbeck. (With a Plate.) .............. 259 a S.teapium, | Dy NE. Brandes cj alas den wee te bene css Cease oe eosse 203 On some Capillary Metallic Tin. By James Smithson, Esq. FRS....... 271 Meteorological Register for Lancaster. By Mr..J. Heaton............ oo 2972 On the Causes, Laws, and principal Phenomena of Heat, Gases, Gravita- tion, Sc. By John Herapatin Bed... 4 36:3 csc ayess oem de'ss bes oats 273 On the Comparative Temperature of Penzance. By Dr. Forbes.... ... 203 Meteorological Results for Manchestes By Mr. Hanson ........... ee 295 Meteorological Register for Cornwall. By E. C. Giddy, RAN ge ths 5 eas 207 rhe New Comet.’ By Dr. Burney. picid cates cv dp ween tintin eee es 208 Rh Cree WON RAN Re hs So Gait gine duis ow bho pase dies wate w ee cee mano 300 - On the Composition of Prussiates. By Prof. Berzelius (continued) ..... 301 Analytical and Critical Account of Dr. Scudamore on Mineral Waters.... 308 Proceedings of the Royal Society, March 8, 15, and 21. ...,....-..008 312 Geolomeal Society, Jin. 14.0... bo. Seco cane ea hs 312 te Ge te ee Bene! od 313 Wet SER IGOR Ss Joti scis ec. cr da reat meas cease weds ave ces anos 317 New iii BS peti Nov ccnlewtlv ays is dian Seage sa sis os heb Bikeats rive’, «op 318 vi : ‘CONTENTS. NUMBER V.—MAY. ‘ Page Observations on the Combinations of Azote and Oxygen. By Thomas reedson; MED. FIRS. eos ok iis I OPTS S.C F 821 . New Galvanic Apparatus, Theory, &c. By Dr. HAR: (With a Plate.) 329 On the Causes, Laws, and principal Phenomena of Heat, Gases, Gravita- tion, &c. By John Herapath, Esq. (continued) ............. Si eeeess 340 _ On the Physiology of the Egg. By John Ayrton Paris, MD............ 351 On the Expansion of the Functions f(x), f(a, y), f(«, y, 2), &c. By Mr. James Adams. ..... Sie "ele oo Winie wb ic ENGI Wie 'ote'e bia Dieta s aa eG eens 259 On Dr. Prout’s Estimate of Mortality from the Operation of Lithotomy. By Jonn Yelloly; MD. FRS. Ske: i560. ees s cock ccceeeeseses vesees GOS Meteorological Results for Gosport.. By Dr. William Burney......... . 364 Meteorological Register for Kinfauns Castle. ...............02e 0.0 cee - 372 Account of an Ascent to the Summit of Mont Blane. By Capt. Undrell, 373 Further Observations on Oil and Coal Gas. By Mr. Ricardo. .......... 383 On Capt. Kater’s Experiments on the Length of the Pendulum ........ 387 Proceedings of the Royal Society, AUG DAMIR ih a's gn cs sige sscices oe 389 Geological Society, Feb. 16, and March 2.......... 390 Astronomical Society, April 13 .........cceceeeeees 392 Purple Powder of Cassius,..........0e0eecseeeces a nadie ee. 393 Quantity of Copper raised in Cornwall Boobs tied acleve tines bisd eee ns sesieiais 394 Native Hydrate of Magnesia dinlide a giniGn ins ih C'e aKmwreal hh eecdlee tak eiae 395 Results of Experiments with a Magnetimeter invented by Mr. Scoresby... 396 Dissection of Crystals......sseseeseseceeeeces Eek Pininig: did Side Maw Tie «p 397 haar Se OO ise ocak i bh i 5 wine ened vconie arise bx behead 397 Wow. Pateate sy ins csikS is eikenspsiccesceeie cael ai bie Ls is alt gone SOS Mr. Howard's ‘Meteorological J sai BR I i ork a ai ig Ss onic bin 399 —— NUMBER VL—JUNE. — On the Causes, Laws, and principal Phenomena of Heat, Gases, Gravita- tion, &c. By John Herapath, Esq. (concluded). ...........cceceaeee 401 Communication from the Rev. H.S. Trimmer respecting Mr. Herapath’s PEXPCriMONth, 65 oins eeeivaie ese c ee tiey Ce eessecssecececce ease geberss ~ 417 Analysis of Verdigris. By R. Phillips, FRSE. &c........... 0. .ceeeeeee 417 Upon the Gas Blowpipe. By Dr. Clarke. ............cccseecceceecves 419 Reply to Dr. Yelloly’s Remarks on the Estimate of Mortality from the Operation of Lithotomy. By Dr. Prout...........5.....0ee eee vette age Upon a new Blowpipe. By Dr. Clarke ...........-00000s esenae asses 498 Cen ONT Bind CON eet wa eee ee arta, Sk hae b caamneeden Ceaweer s « 431 On the Composition of the Prussiates. By Prof. Berzelius (continued)... 433° On the Application of Howard’s Fulminating Mercury to the Discharge of Ordnance. By Mr. Joh Deuchar..........i.sccccwcectcccec cscs 449 On the Structure of the Alps, and adjoining Parts of the Continent. By PPrOly THM. 5 sain cc cccn cc coven g cence aac KbOMGMEOR ES ce bo'e)> \:cenammme 450 Proceedings of the Royal Society, May 3, 10,17, and 24.......seeseeese 468 CONTENTS. vii Page Composition of Rhubarb. ..........ceeeceee cee eees scsevecvevcsvesse 409 Rocks of Mont Blanc...........«. i abala a idiwiaiote et re eT Viateie iva 469 Granulation of Copper, .....-..ecsscsereceeees Laan Ran He ee hbk ey Gsecns 469 Analysis of Indian Corn.........0000 bE ciepb ob sealeuien dking Seem eva 470 On the Iodide, ois and Chlorides of Gold... LeMadeweirbtinsvan 420 Neéw Scientific Books .. COSCO Reo ea seer CeoeBeeesevdesosevewsies cbse ee ee ae 471 pS SOT RENCE Tn MENT tet iy: ind aaeldn whites copulate ‘waves 472 Mr. Howard’s i pa Journal for Api Vile sive Weave visa! ARG Index... sess essere eoewes ie eseoeveve Serv eve weeeveescneeceor eeen eee eoeo eee 475 PLATES IN VOL. I. (New Series.) si Plate ate I.—A remarkable Stratum of Limestone situated at Calder BUG. ieee. 28 T].—Pratt’s new Climometer.. 0%. ccccered vevecenesionevers seem caes 43 TII.—Apparatus for discharging Ordnance. ..........ceceeeeesseneeee 89 IV.— Tread tn = On). n. n ie ERRATA IN VOL, I. New Series. Page 46, last line, for three inches, read eight inches. Jor three inches from the bottom, read eight inches. It escaped notice, until too late, that in both these instances, the printer had mistaken a figure of eight for three. The dimensions, as corrected, are those of the boiler and fire-place used in some expe- riments made at Bromley; in the greater number of those alluded to by Dr. Bostock, the dimensions of the boiler and fire-place were as follow: — Boiler.—Three feet long, 15 inches wide, and 15 inches deep. Fire-place.—Nineteen and a half inches long, nine inches and a half wide, and ten inches deep. Page 57, line 31, for 30, read 25. 58, line 9, for one atom of deutoxide read four atoms. 89, line 35, for a, the joinings, read at the joinings, 36, for we, read were. 94, line 8, for flannel, read flame. 98, last line, for equations, read equation. 105, line 4, for N, read D. x? x7 iuisties (TERE PERL 22, for C, read b. 136, line 6, for Mezthyr, read Merthyr. 34, for thin bitumen, read elastic bitumen. 160, line 5 from bottom, for Capricornus, read Sagittarius. 212, line 32, for burning, read liming. 218, line 34, for being change, read being no change. 38, for on chlorine gas, read in chlorine gas. 222, line 36, for pel de singette, read sel de Seignette. 7, from bottom, for distilled, read deducted, 274, line 3, from the top, for FRS. read VPRS. 276, line 11, from the bottom, for receive, read conceive. 287, line 18, for (a — 5), A, read (a — b) A, “ADVERTISEMENT. -bolberosecrep the Annals of Philosophy inthe year 1812, and have continued to be'the Editor ever since, with the exception of a single year, when my sudden removal) to Glasgow, and the necessity I was under of beginning a laborious course of Chemical Lectures with scarcely any previous preparation, and with no assistant, put itout of my power to devote a sufficient portion of my time to the laborious and diversified duties of Editor of a periodical work of science. My friends Dr. Bostock and Mr. Arthur ‘Aikin were kind enough to supply my place during that year; and carried on the Annals of Philosophy with a spirit which left the readers no cause to regret the tempo- rary absence of the original Editor. The principal object “which 'T had constantly in view was to render the Annals as complete a register as possible of all: the: improvements made in chemistry and the kindred sciences, not merely in — "Great Britain, but in every part of the world. How far-my ‘exertions were attended ‘with success, it is not-for me to determine, though I can say with truth that neither labour ‘or expénse was spared to fulfil, as far as was in my power, ‘the objects which I had in view. “After a trial of two years, Thave satisfied myself that a residence more than four’ hundred ‘miles distant’ fromthe place of publication is scarcely consistent with the active duties of an Editor. It more than quadruples the labour, while it-diminishes, almost: the same proportion, ‘its suc- cessful exertion. I have, therefore, with the concurrence of the publishers, transferred the Editorship of the Annals of Philosophy to my friend Mr. Richard Phillips, a gentleman whose scientific talents and acquirements are too well © known to require any observations on my part. New Series, vou. 1. A 2 ADVERTISEMENT. But though I relinquish the Editorship, I do not abandon all interest and concern in the work. I shall still continue connected with it, and, I trust, shall be a frequent and active contributor, though my absence from the place of publication renders the labours of the active Editorship irksome and painful. In consequence of this change, it has been determined to denominate the. seventeenth volume of the Annals of Philosophy the First of a New SERIEs. Glasgow, THOMAS THOMSON. December, 1820. I undertake the Editorship of the Annals of Philosophy, announced in the above advertisement, with some anxiety, lest the reputation which the work has acquired should be dimi- nished by being placed under my controul. The friendly assurances of Dr. Thomson, that he will continue to contribute tothe Annals, will, I trust, convince the reader that the work will in future possess a great share of its present value. The successful management of a scientific journal is ren- dered doubly difficult by the numerous similar sources through which information is now conveyed: relying, however, upon the favourable circumstances in which I am placed for the early acquisition of philosophical intelligence, I trust I shall be enabled, with the assistance of which I have received nume- rous promises, to render the work not unworthy of the patro- nage and support of the scientific public. London, RICHARD PHILLIPS. December, 1820, ANNALS OF PHILOSOPHY. JANUARY, 1821. a ARTICLE I. Experiments to determine the true Atomic Weight of Strontian, Lime, Magnesia, Phosphoric Acid, and Arsenic Acid. By Thomas Thomson, M.D. F.R.S. In two papers published inthe preceding volume of the Annals of Philosophy, 1 have endeavoured to determine the real weight of the atom of 13 simple bodies, and a considerable number of compounds formed by the union of these bodies with each other. In every one of these cases we found reason to conclude that the atomic weight of every body is a multiple of the weight ‘of an atom of hydrogen. I showed that the detsmmusliots of ‘Dr. Wollaston and Prof. Berzelius, though in most cases consti- tuting very good approximations, are never rigidly exact, the true weights of the atoms of bodies constituting much simpler numbers than they have supposed. I have shown, I trust to the satisfaction of all practical chemists, that the mode of experi- menting adopted by Berzelius is not precise enough for the determination of the weights of the atoms of bodies. I ought to observe, however, that Berzelius is undoubtedly a very great master of the analytical art; that his analyses approach upon the whole exceedingly near the truth; and exhibit a consistency which is highly satisfactory, and does a great deal of credit to the industry and sagacity of their author. But unfortunately his mode of experimenting admits of no criterion by which the experimenter can determine whether the results be accurate or not ; so that he has no means of checking himself, and of taking A2 4 Dr. Thomson ‘i the true Atomic Weight of [JaN. | those precautions which a knowledge of the existence of error would lead him to look for. The mode of experimenting which I have employed has the eat advantage of infor ae the experimenter whether or not is results be accurate. en I mix together a given weight of sulphate of potash and nitrate of lead, it is easy, by examin- ing the clear liquid which remains after the precipitate has dalieided to ascertain whether that liquid holds in solution any sulphuric acid or any oxide ; thus showing whether either of the salts has been employed in excess, and which of the two. We are thereby enabled to vary the weight of each salt till at last we hit upon proportions which exactly decompose each other without leaving any excess whatever. The knowledge of these proportions enables..us, by the methods explained in the papers above alluded to, to determine the real weight of the atom of the bodies which are the subject:of experiment. This method is tedious, and requires no great share of dexte- rity in experimenting. We must take care that our salts are pure and dry ; that they are accurately weighed out, completely dissolved in distilled water, and the solutions well mixed without any loss whatever. Whoever attends to these precautions will be enabled to come to results as near absolute accuracy as is consistent with experimenting. I have made considerable pro- ¥ aie in determining the weights of the atoms.of the acids and ases by this method ; but at present 1 mean to confine myself to the experiments made to determine the atomic weights of the five substances whose names are placed. at the head of this essay. The following table exhibits the numbers. assigned to ‘the atom of these bodies by Dalton, Wollaston, Berzelius, Prout, and myself: Dalton. |Wollaston.| Berzelius..| Prout. . |'‘Thomson. Strontian. ....... 6571 | 6-9 129460 | — : MAINA. who's wrniesie 3°428 | 3°546 | 7:1206 | 3:5 | 3°625 Magnesia. .......| 2°428 | 2°46 51672 | — } Phosphoric acid. ..| 3-285 | 3°74 8-9230 | 3°75 | 3°5* _Arsenic acid....., = — | 144077 |. — | 7:25 — To enable the reader to compare Berzelius’s atoms with the others contained in the table, it will be proper to bring them down to smaller numbers. This may be wile by dividing each - by 2. They will then be reduced to what they are in the following table : | * In the fifth edition of my System of Chemistry, I made it 4*5, deceived by the expe- -riments of Berzelius and Dalton. But I have long ago corrected this mistake. 1821.] Strontian, Lime, Magnesia, Phosphoric Acid, &c. & Strontian ...... L ieye de ecds a age wweae OL7au') BGs ess tee i we « 3°5603) ° Magnesia ....sesscessccsnsscees 2°5836 Prrepeoric BON Pe fe 4°4615 WEPRDONG, DOI. 'a ose asd ere preg Bk distordie A ROOD When thus stated, they approach very nearly to: the other atomic numbers contained in the table, though the number of decimal places is sufficient to render their absolute accurac suspicious. They want one of the criterions which J have shown, in my preceding papers, that the real atomic weights. of bodies possess... They are none of them multiples of 0-125, the weight of an atom of hydrogen. Dalton’s numbers were obtained by dividing the atomic weights which he gives in his System of Chemical Philosophy by 7, which is his weight of an atom of oxygen. This is a fairer method than the one which I employed in my last paper. 1 there took in his error with respect to the weight of oxygen when compared with hydrogen. Here that. error is not reckoned at all, but tacitly corrected. Let us now have recourse to experiments to determine which of these columns comes nearest the truth, or whether any of them be absolutely correct. Sulphate of soda is composed ag. follows: : Salphariecacidh »siscnssnereiete-ejeieane oe naSiaa Sm» 5 REM kk sitige' sontees I Ee, Re wa Sulphate of soda. ..ssscsseeeseseeees Lg According to the numbers.which I have made. choice of for ehlorine and strontium, chloride of strontium is composed of SS AMIIUNL x: debt hav ihdcg cs ois. ahvasaa vette bien 4°5 Pep OMB ER. iain echimtecich') beens die ne memes Wie 5:5 Chloride of strontium..........e+eee- 10:0 To determine whether these numbers be correct, I. took nine grains of sulphate of soda recently kept for half an hour in the state of igneous fusion, and: dissolved it in'a small quantity of distilled) water. I likewise dissolved im another: portion, of distilled water’ 10 grs. of chloride: of strontium, recently: fused and perfectly dry. These two liquids were, carefully mixed together, and allowed to remain in contact for24 hours. I then drew off a portion of the clear liquid, and examined it. No change whatever was produced in it by nitrate of barytes. Of course, it contained no sensible quantity of sulphuric, acid. It _ was not rendered in the least turbid by sulphate of soda, poe phate of soda, arseniate of soda, or chromate of potash. Hence there is no evidence that it contained any strontian, fs I consider myself as warranted by the preceding experiment to’ conclude, that chloride of strontium is composed of | 4 - 6 Dr. Thomson on the true Atomic Weight of — [JAN. Chlorine. ...... artes A sae o «6 0 bets era Strontium . 0... .cevevesescecsccvens 55 10-0 Consequently muriate of strontian is composed of Muriatic acid .............- pabudete- G25 BerOhsiean as seek wt. Pes as Elser, 6°5 | 11°125 It is obvious, therefore, that the true weight of an atom of strontian is 6:5, the very weight which I have already assigned. The above experiment will neither succeed with Dalton’s, Wol- laston’s, nor Perzatins’s numbers—a sufficient proof that none of them is absolutely correct. 2. I made a great many trials before I-was able to determine’ the weight of an atom of lime; but I consider it as needless to relate those which were unsuccessful. Indeed I failed so fre- quently that I for some time despaired of being able to deter- mine the point. However by persevering and trying one method after another, I at last hit upon a way which is quite easy, and which, if carefully performed, yields most satiathetity results. No salt of lime which I tried possessed sufficient solubility, and the capacity of being totally deprived of water by heat without decomposition. I was obliged, therefore, to have recourse to calcareous spar. I took pathy ure calcareous spar, reduced it to a coarse powder, and exposed it for an hour to a tempera- ture of between 300° and 400°, which renders it perfectly d without disengaging any sensible quantity of carbonic acid. ts will appear by the experiments which I am going to relate, that pure dry carbonate of lime is composed of Carvomic O08 iis Peeves Cee, se nat ED Lite: 2.338055 ee eR Pe 3°5 Carbonate of lime .............0 hy 625 _ When pure crystals of bicarbonate of potash are exposed to, a red heat in a crucible of platinum, one half of the carbonic acid is driven off, and there remains pure and dry carbonate of potash. Now this saltis composed of Carbonic acid. ........000. gS egronitay Phi yal 05 Es ania 5 5m Pures ws ain al chs nce Carbonate of potash..........2000+. 8°75 The knowledge of the composition of these salts will enable - reader easily to follow the experiments which I am going to Telate. 6:25 grs, of dry calcareous spar were dissolved in muriatie 1821.] Strontian, Lime, Magnesia, Phosphoric Acid, &c. 7 acid, and the solution was evaporated to dryness on a sand-bath at a temperature not much sib 100°. The dry salt was’ then dissolved in distilled water. It obviously contained 3°5- grs. of lime saturated with muriatic acid ; and from the result of the experiment, it will immediately appear that muriate of lime is a compound of | WEUPIALIC BOIG 6: os bs ebe.0. #0 ue trae eo A cca ar nits uk Gina ea ie tats scien ae ee DENTO OL WUDG Sco sare 0:0 «iacnanatecndch 8°125 8:75 gers. of carbonate of potash were dissolved in a separate portion of distilled water, and the solution was mixed with that of the muriate of lime. A double decomposition took place, carbonate of lime precipitated, and the clear liquid held muriate of potash in solution. A portion of this liquid was drawn off and examined. It produced no change upon the colour of paper stained red by cudbear.* Oxalate of ammonia occasioned no precipitate in it. From these facts I consider myself entitled to conclude that the whole of the carbonate of potash was exactly neutralized by muriatic acid, and that the whole of the lime had been precipitated in the state of a carbonate. It obviously follows that the weight of an atom of lime is 3°5. This is the atomic weight already assigned by Dr. Prout. My num- ber is too high, and Mr. Dalton’s too low. The number of Wollaston and Berzelius is much nearer the truth than either Dalton’s or mine, though both of them are rather too high. To enable the reader to judge of the accuracy of the preceding conclusion, it may not be amiss to select two out of the great number of experiments which 1 made with a view to determine the weight of an atom of lime. (1.) If we suppose the atom of lime to weigh .3°625, which is the atomic weight that I had pitched upon, then it is clear that dry carbonate of lime must be composed of PSFOODIG BOIG. ac oc 05 oso x's sida sig Gece an’ ee WR ear ea gcd Sas #16 4iG. 8b Wrecibtacae ae ee Carbonate of lime. .......... ate af 6°375 To verify this supposition, I dissolved 6°375 grs. of dry car- bonate of lime ‘in muriatic acid, evaporated the solution to dryness, redissolved the residue in distilled water, and mixed it with a solution of 8°75 grs. of carbonate of potash. After the , carbonate of lime had precipitated, a portion of the clear liquid ~ was drawn off, and some oxalate of ammonia dropped into it. An abundant precipitate of oxalate of lime fell down. Hence _* This is the most delicate test of alkalies that I am acquainted with A very minute portion of alkali or alkaline carbonate renders it violet coloured. & _ Dri Thomson.on the-true Atomic Weightof [Jiani limerstill. remained in ‘solution; consequently the. carbonate. of h had. not been sufficient to. throw down all the lime... We: see from this. that an atom of lime is not’ so heavy as,3-625. ' (2.) The nearest. multiple of 0°125. to. Mr. Dalton’s atomie ht of lime.is 3°375... Now if this,be the weight of an atom: of lime, it is plain that dry carbonate of lime must. be com» posed of | Carbonic acid cee eee etete eos Fe OPFG Lime.. Seco eecceceecsrevcevneeeveevetes 3°375 Carbonate of lime: ....... tag Beak tues 6125 * To verify this supposition, I dissolved 6-125 grs. of carbonate éf‘lime ‘in muriatic acid, and after treating the solution in the manner already described, I mixed it with a solution of 8°75 es ‘of carbonate’ of potash. After the! carbonate of lime had! subsided, the clear supernatant liquid was not precipitated b oxalate of ammonia, and, therefore, contained no lime; but it’ imstantly rendered cudbear paper violet, and therefore contained: amexcess of potash. Hence the muriatic acid united with the lime liad not been sufficient to saturate the whole of the potash. fis clear from this that an atom of lime is heavier than 3:375. ‘These-experiments are sufficient I trust'to satisfy the reader that the true weight! of an atom of lime is 3°5. 3.‘1 found muelr less difficulty in determining the weight of an atom of magnesia than of lime. Sulphate of magnesia may: Weexposed to-a red heat, and rendered thoroughly aes without. losing any of its acid, if the experiment be properly conducted. ifthe weight of an atom of magnesia, which I have assigned, namely, 2-5 be correct, it is obvious that anhydrous sulphate of? magnesia is composed of Sulphuric. acidsj..ecs essences oan oe BOQ 1 [MAR GDORIR Gg sisoies-ie dice ine olawth é with) winaisdrldyi Sulphate of magnesia .........0.eee0 bas Anhydrous chloride of barium, as I demonstrated in a former paper, is composed of ~~ Pe el } GUBMNG receccscciciss pte 4:5 f Barium ee on eee eenweveee “ee ee @ @ eoreeeeaene 8°75 ‘gk nolviiediabiatsleans, bine, iteinn nik alle 7-5 grs. of anhydrous sulphate of magnesia, and 13:25 grs,;of, chloride of barium, were respectively dissolved in) two. distinct.. ortions of distilled water, and the solutions mixed together,.. ad well agitated. After the sulphateof barytes had subsided, a rtion of the clear liquid was drawn off and examined : neither sulphate of soda nor nitrate of barytes occasioned any precipitate or muddiness, in it. . Hence it is obvious, that. the liquid:neither.,. 1821] Strontian, Lime; Magnesia, Phosphoric Acid, &c. contained any barytes: nor any sulphuric acid in solution’; so that! the sulphuric:acid m the’7-5 grs. of sulphate of magnesia. had just saturated the barytes from 13-25 grs. of chloride of barium. It is obvious then that the true weight of an atom of magnesia is 2:5; therefore, the, atomic weight assigned by Dalton and Wollaston is too small, while that assigned by Ber- zelius is too high. Accordingly, if we mix together anhydrous sulphate of magnesia and chloride of barium in the proportions indicated. by these numbers, we shall in the one-case find an excess of sulphuric acid, and in the other of barytes, in the liquid after the precipitate has subsided, indicating obviously an error in the weight of the saits thus mixed together, and consequently an error in the numbers assigned by these gentlemen for the weight of an.atom of magnesia. y oll 4. The weight. of an atom,of phosphoric acid has cost me, first and last a good deal of trouble. I have the happiness, however, at last to be able to lay before the reader experiments of so decisive a nature that no doubt nor uncertainty can rest upon the subject for the future. In the year 1816 I drew'up a paper-upon the subject, the result of a good many experiments, which was read before the Royal Society.. Some discussion, took place in the committee.of papers relative to these experi- ments; and Dr. Wollaston, who was a member of. that, commit= tee, and to whose friendship and, assistance I, have been, very frequently obliged, kindly brought the paper to me to give me an opportunity .of correcting some. numerical mistakes which ne had observed in it.. . By this time .I had made the experiments on phosphuretted hydrogen gas, which were.soon after published in the Annals of Philosophy. These experiments had made me acquainted with the true weight) of the atom of phosphorus, phosphorous acid; and phosphoric’ acid, and had explained all: the errors into which I had fallen in my original paper. I had, therefore, been extremely desirous of withdrawing my paper from the Royal Society, in order to‘have an opportunity of cor= recting it. Ofcourse, when it was put into my hands by’ Dr. Wollaston, I requested of the Society to be allowed to keep’ it, and this request they were kind enough to indulge me in. . Just at:the time that) my proof sheet giving an account of phosphorus in the fifth edition of my System of Chemistry was: immy possession, [received Mr: Dalton’s short paper on phos= aan hydrogen gas, which was printed in the Annals of -hilosophy.: In that paper’ Mr: Dalton states that phosphuretted hydrogen gas. is capable of condensing twice its volume of oxygen'gas.’ ‘I-hadjjust before been:informed by Gay-Lussac of Dulong’s discovery of hypophosphorous acid, and had read over’ Berzelius’s paper on phosphorus and its’ ¢ompounds; in which he: shows’ bya number of analyses agreeing very well with each® other: thatthe atomic weight of: phosphoric acid’ is 4°5, or at’ least:very near thatnumber. Being perfectly sure of the accu’ 10 Dr. Thomson on the true Atomic Weight of [Jan. racy of my own experiments, and not suspecting any inaccuracy in Mr. Dalton’s, I naturally concluded that phosphuretted hydrogen gas was capable of uniting with three proportions of oxygen gas; namely, Rr “1 volume phosphuretted hydrogen with 1:0 volume oxygen ) 1-5 | 1 2:0 | The first two of these proportions were my own ; the last was Dalton’s. Now phosphuretted hydrogen gas is composed of 1 volume hydrogen gas 1 volume phosphorous vap gat condensed into one volume. The volume of hydrogen gas requires half a volume of oxygen gas to convert it into water. Therefore, we have 1 volume phosphorus uniting with 0:5 volume oxygen ‘0 1 15 This is the same thing as saying that an atom of phosphorus unites with one atom, two atoms, and three atoms of oxygen. I had demonstrated that an atom of phosphorus weighs 1°5. Hence it was obvious that the weights of these three compounds of oxygen and phosphorus must be as follows : First compound. ....... bE ote'e je BH Second ditto. .... IOI BE ek ee bE Oe 3°5 Third: ditto. ¢:2i.60.% vs ik Me UOLER sed 4°5 I concluded that these three compounds were hypophospho- rous acid, phosphorous acid, and phosphoric acid. This recon- ciled my own experiments with those of Dalton and Berzelius. I was induced by this reasoning, which will be admitted to be sufficiently plausible, to alter the proof sheet, and to bring it to the state in which it appeared in the fifth edition of my System of Chemistry. Soon after this I went to Glasgow, and nearly a year elapsed before I was in possession of a laboratory, or had it in my power to return to the subject. As soon as I had the means I tried Mr. Dalton’s experiment, and was a good deal surprised to find it inaccurate. pt unable to obtain a complete combustion of a mixture of one volume phosphuretted hydrogen gas and two volumes of oxygen. I was now satisfied that my original views on the subject were correct; and Davy’s paper on the subject, which appeared about this time, and which agreed exactly with my original views, served to confirm my opinion. Berzelius’s experiments still remained to be accounted for. I was satisfied that they must be inaccurate; but the difficulty was to hit upon a method of demonstrating them to be so. -The experi- 1821] Strontian, Lime, Magnesia, Phosphoric Acid, &c. 11. ments which I am now going to relate will leave no doubts on the subject in the mind of any practical chemist. I do not know how Berzelius has deceived himself; but that he laboured: under some deception or other will not admit of a doubt. It would be tiresome and perfectly unnecessary to relate the. numerous experiments which I made to determine the weight of an atom of phosphoric acid. I shall confine myself to those which answered the object that I had in view. If Berzelius’s opinion respecting the weight of an atom of phosphoric acid be true, then anhydrous phosphate of soda is composed of Phosphoric. acid .. c.cccsccscccescens 4°5 OR eae dake. chee Sane snes 4-0 Phosphiite Of 86a es oe ee 8 8°5 We have seen in a former paper that dry nitrate of lead is composed of | PONG WOO ed eo win a ore wale Bh sana 6°75 Protoxide of lead!)'} SU 8 iF sek bes. 14-00 Nitrate (oflaades 3) 206 sc 2ds laeseccviien 20°75 To put Berzelius’s analyses to the test of experiment, I exposed a quantity of pure crystallized phosphate of soda to a. red heat, and kept it in fusion for half an hour. 8°5 grs. of this anhydrous salt and 20°75 grs. of dry nitrate of lead were respec- tively dissolved in separate portions of distilled water, and the solutions were intimately mixed together. After the phosphate of lead had precipitated, a portion of the clear liquid was drawn off and examined. ‘It yielded a white precipitate when mixed with nitrate of lead and with muriate of lime. Hence it obviously contained phosphoric acid in solution. Hence the oxide of lead in 20°75 grs. of nitrate of lead is not capable of neutralising all the phosphoric acid in 8°5 grs. of anhydrous phosphate of soda. It follows from this that Berzelius’s statement of the composition of phosphate of soda is incorrect. if my own opinion respecting the composition of phosphoric acid be true, its weight must be 3°5, and anhydrous phosphate of soda must be composed of Phidaphiovi¢' acid 33 ))¢..02900 0 6. PRs: 2 BOM OS POR ys FORGE eC Prey i555 #0 Phosphate of soda We (hdabectioniyves 75 To verify this opinion, 7:5 grs. of anhydrous phosphate of soda and 20°75 grs. of dry nitrate of lead were dissolved respec- tively in separate. portions of distilled water, and the solutions uuxed together. After the phosphate of lead had subsided, a 12 Dr. Thomson on the true Atomic Weightof § [Jaw. ortion of the clear liquid was drawn off and examined. It: yielded no precipitate when mixed with nitrate of lead or muriate! of lime ; and, therefore, contained no phosphoric acid in solu- tion ; neither was it affected when sulphate of soda was dropped: into it—a proof that it was equally free from lead. We see then that ‘the phosphoric acid in 7-5 grs. of anhydrous phosphate of soda is exact y neutralized by the oxide of lead in 20-75 ers. of nitrate of lead. Therefore an atom of phosphoric ‘acid weighs 3°5, and phosphate of lead is composed of Phosphoric acid... 3°5 .... 20 .... 100 Oxide of lead. .... 14:0 .... 80 .... 400 17:5... 100 Here then is the source of Berzelius’s mistakes.. He makes the composition of phosphate of lead to be : BW QRDAROEIG RONG 5655. iinin ose ainve 9 8:90 0:8)0 100. Protoxide of lead. ....... RULE ape r 314 I do not know the reason of this difference. It must, I think, be owing either to a mixture of two phosphates of lead, or to the formation of a compound different. from neutral phosphate of lead. I obtained a result approaching to that of Berzelius, when I attempted to determine the composition of phosphate of lead by direct experiments. But be the cause of the error what it may, there can be no doubt entertained of its existence, at least by. any person who will take the trouble to repeat the experiment which I have just described. We see that the weights of the atom of phosphoric acid and’ of lime are exactly equal. Hence neutral phosphate of lime is composed of PHOspli vie Wid 000i 04 GG criss ne 50. TRON A CGT RADA DAL 10, teasidictedia 50 100 _ When I first attempted to determine the weight of an atom of phosphoric acid, I had recourse to salts of lime, knowing the perfect insolubility of phosphate of lime in water. I dissolved determinate weights of carbonate of lime in muriatic acid, evapo- rated the solution to dryness, and mixed it with a determinate weight of phosphate of soda; but I soon found that itis impos- sible to precipitate lime completely from a muriatic acid solution of lime (though perfectly neutral) hy means of phosphate of soda. The solution of muriate of soda has the property sf holding phos- hate of lime in solution, and the presence’ of lime is always indicated in the clear solution by means of oxalate of ammonia, which throws down a copious precipitate of oxalate of lime. E have no doubt that this solubility of phosphate of lime in solu- -1821.] Strontian, Lime, Magnesia, Phosphoric Acid, &c. 13 tions of muriate of soda, and probably in many. other sale -solutions, has misled experimenters in their attempts to, analyze the phosphates. : . ist [intend the first leisure opportunity to correct. my old paper on phosphoric acid, and give it to the public. It contains many facts still unknown to chemists in general, notwithstanding the experiments of Berzelius, on the subject; and now that. l.am aware of what the true composition of the phosphates is, it will not be so difficult to obtain accurate results. 5. The exact knowledge of the weight of an atom of arsenic acid is of considerable importance towards. the perfection of the atomic theory. Hitherto Berzelius is almost the only person who has made direct experiments to determine the atomic weights of arsenious and arsenic acids. . He has concluded from his experi- ments, and the conclusion seems to have been acquiesced in by chemists in general, that the oxygen in arsenious and_arsenic .acids are to each other in the ratio of 3 to 5. It will be seen from the table near the beginning of this paper, that my atomic number for the weight of an atom of arsenic acid very nearly agrees with that of Berzelius. In a paper published in a late volume of the Annals of Philosophy, indeed, I endeavoured to show that the double of my number, or 14:5, which very nearly agrees with the number actually pitched on by Berzelius, is the real weight of the atom of arsenic acid. The object which-I had in view was to get rid of certain fractions which disfigure the composition of arsenious and arsenic acids as I represented them in the fifth edition of my System of Chemistry. ‘The expe- riments which I am now going to relate will show how far these views. are consistent with matter of fact. Ifarseniate of soda in crystals be, as I represented it in a pre- ceding paper, a compound of | atom arsenic acid = 14:5 and 1 atom soda = 4, then its composition must be as follows : ATR CRG GIG anid inde hci 0 iini's) 00 ale dsiait dlerdeyO (BPedalojaes: vdai SSUekd oki oioiee, o Détob Sars w tO Redcninto dh sada o dort « srccccinccce cer ho : . We have-seen already that nitrate of lead is composed. of PO TERUPMON a ce asin gin hk aniae Sever, eh Protoxide of lead........ Selita cae EO en ee Nitrate*bf lead 3.05 wie Bee QOS _ 18:5 grs. of arseniate of soda previously kept in a state of igneous fusion for half an hour in a platinum crucible, were dis- solved in distilled water. 20°75 grs. of nitrate of lead were dissolved in: another portion of distilled water, and the two solu- tions mixed intimately with each other. . After the arseniate of lead had subsided, the clear liquid was drawn off and examined. When mixed with nitrate of lead, a very copious precipitate fell, 14 Dr. Thomson on the true Atomic Weight of — [Jan. ‘showing that the liquid still contained a great deal of arsenic acid; consequently the sad ipo yam that the crystallizable arse- niate of soda is a compound of one atom arsenic acid and one atom soda cannot be well founded. This will appear still more clearly by the following experiment : \ Supposing that the crystallized arseniate of soda contained “two atoms of arsenic acid united to one atom of soda, I tooka quantity of carbonate of lime, equivalent to two atoms of lime, which is obviously 12°5 grs.; for carbonate of lime is com- posed of Carbonic acid. ........ afeeeseuss) j oN 2°75 Lime. . e*eeeeerse#e eeseeervresteeoeeeeeseeneeee 3°50 Carbonate of lime........ SA bie dsncteae And 6°25 x 2 = 12:5. This quantity I dissolved in muriatic acid, evaporated the solution to dryness, and dissolved the dry salt in distilled water. 18°5 grs. of dry arseniate of soda were “dissolved in another portion of distilled water. These two liquids were mixed together. I was surprised to find that no precipitate of arseniate of lime, or at least only a very slight one, appeared. The solution had the property of reddening vegetable ‘blues. We see from this, that binarseniate of soda is incapable of decomposing muriate of lime. When ammonia was poured into the solution, a copious precipitate of arseniate of lime fell ‘in small silky needles. After the precipitate had subsided, the clear liquid was found to precipitate, when mixed with oxalate of ammonia. It, therefore, contained an excess of lime. This experiment shows clearly that the crystallized arseniate of soda is a binarseniate, and that an atom of arsenic acid weighs more than 7°25, the weight which I assigned in the fifth edition of ‘my System of Chemistry. : | After a great many trials, which I consider it as useless to relate, I found that 19°5 grs. of binarseniate of soda and 41°5 grs. of nitrate of lead, when separately dissolved in distilled water, and the solutions well mixed together, after all the arse- niate of lead had precipitated, left a clear liquid which contained no sensible quantity of oxide of lead, or of arsenic acid. But if 18-5 grs. or 19 grs. of binarseniate of soda were employed, an excess of lead always remained in solution. From this experi- ment, it is obvious that the equivalent number for anhydrous binarseniate of soda is 19°5, and that it is a compound of 2 atoms arsenic acid = 15°5, and 1 atom soda = 4. Hence an atom of arsenic acid, instead of weighing 7°25, as I supposed, weighs in fact 7°75, and arseniate of lead is a com pound of PAYGRIIC BRIG.” ois’ we'o os pee ean peMet ra 10 Protoxide of lead........ ‘op eUsne ees. LF 00 — Riverbateiol lead’, i «('i2h }y 260i sei QUT 1821.] Strontian, Lime, Magnesia, Phosphoric Acid, &c. 15 There is reason to conclude from the experiments made by different chemists on arsenic and arsenious acid, that the weight of an atom of arsenic is 4°75. It may be seen by consulting m System of Chemistry (either fifth or sixth edition) that Berzelius’s experiments lead to the conclusion that arsenious acid is a com- pound of 4°75 arsenic + 1-5 oxygen. The preceding experiment leaves no doubt that arsenic acid is a compound of 4°75 arsenic + 3 oxygen. Thus we have these two acids composed as follows : Arsenious acid of. .. 4°75 arsenic + 1°5 oxygen Arsenic acid of. .... 4°75 + 3:0 We see that the oxygen in these two acids has not the ratio of 3 to 5, as Berzelius supposed, but of 1 to 2. The anomaly of 14 atom of oxygen combined with 1 atom of arsenic in arse- nious acid still continues. I have not yet hit upon a method of putting the atomic weight of an atom of arsenious acid to the test of an unequivocal experiment ; but I have little doubt that the true weight of oxygen in arsenious acid combined with 4°75 arsenicis 2; and that the oxygen in arsenious and arsenic acids have to each other the ratio of 2 to 3; as is the case in sulphu- rous and sulphuric acids. I conceive the atomic weights of arsenic, arsenious, and arsenic acids, to be as follows : Weight of atom. Arsenic eeeeeoeoseeeeeveesesee7eseeeeespesevee 4°75 PER OMICTS MOT ° 5015) 4 \e- 050.98 cere Se pawns 9:7 OOO WROD. GONE 0555.5 hase ee sk oan, dO The two acids are composed as follows : Arsenious acid 1 atom arsenic + 2 atoms oxygen Arsenic acid.. ] , “hid I do not despair of being able to decide this very important - point hereafter by satisfactory experiments. In the mean time we may conclude that the ratio of 2 to 5, which Berzelius has endeavoured to establish in the oxygen combining with phos- phorus and with arsenic, does not exist. This is a simplification of the atomic theory of some importance. I am thoroughly per- suaded that as we proceed in our investigations, the simplicity of the atomic theory will become more and more apparent. The complex numbers of Berzelius will all disappear; and the appli- cation of mathematical reasoning will by and by enable us to advance with unexpected rapidity in the chemical investigation. of the vegetable and animal kingdoms. 16 Mr. William Phillipson ‘[Jan. ~Articre II. ‘On the Geology of the Malvern Hills. By William’ Phillips, RLS. MGS L&C. and Hon. Mem. of the Cambridge P to. -sesophical Society. | .» Tue Malverm range of hills is peculiarly interesting as bein surrounded by deposits which appear to have little pectogibll connexion with. its rocks, as well as from the remarkable com- position of the latter. In the first volume of the Transactions of the Geological Society, there is an interesting communication on the subject, by Leonard Horner, Esq. FRS. &c.; buthaving, as I imagine, observed some. circumstances deserving of note which escaped the notice of that gentleman, I venture to sup- ‘pose them worthy of a place in the Annals of Philosophy ; and as it would be difficult to render these observations intelligible. without giving a general account of the range, I am induced to incorporate them with extracts from the paper above-mentioned, distinguishing such extracts by placing them between inverted commas; thus affording to the traveller a comprehensive view of this singularly interesting range, but premising that he will find, in the first volume of the Rictiea tone of the Geological Society, many minutie which do not appear essential to the present object, which is primarily to show that the rocks of this range aré occasionally stratified ; and secondly, to do away the too commonly received and erroneous opinion that they partly consist of granite. | “The Malvern hills are.situated in. the south-western, part) of Worcestershire; the boundary which divides the counties of Worcester and’ Hereford passes along their western side. pet consist of an uninterrupted chain of about nme miles in lengt from north to south, their greatest breadth. not exceeding two miles. The several parts of the chain present. roundish,sum- mits,” but the nearly continuous line formed by the summit.of ‘the central part of the range forms a mae narrow ridge, which, except here and there, is, in common with the rest of these hills, covered with short grass and moss : ;fern is alsojseen on the sides, except where the rocks rise from beneath. the vegetation. “The highest point of the range is. the Worcestershire Beacon, which is 1444 feet above the level of the) sea ; the Herefordshire Beacon, and North Hill, are somewhat.lower.” The range is flanked on the western side by,limestone,in remarkably regular strata dipping generally to the north or north-west, at a low angle, and on the east, and the north and south extremities, by the New Red Sandstone or Red Marle, which is visible beside the road in two or three places on the south of Great Malvern, at a higher elevation than that place, A821.) the Geology of the. Malvern Hills. VW -and at the nearest to it in strata dipping to the east conformable with the dip of the hill, it is, therefore, very considerably higher than the country on the east of the range which consists of the same deposit. : The soil which supports the moss and grass with which these hills are generally covered appears, for a few inches in depth, te assume the character of vegetable mould, but that there is below it, and covering the rocks of which the hills are constituted, a depth of loose earth, is not only evinced by the generally smooth surface of the hills, and by the occasional openings beneath the vegetation, but also by the fresh mole-hills which are found in many places, and even near the summits of some parts of the range. This loose earth varies in colour from that of common sand to a fawn colour, and in substance sometimes resembles sandy loam in appearance: it is probable that it. has resulted from the decomposition of the softer and more readily decom- posable rocks of these hills, and it is owing to this decomposition that ‘“ the comparatively little opportunity for examining the nature of the rocks of this range is confined to those which rise here and there on the summits and sides above the grassy cover- ing, and to the sides of the carriage road which runs near its base for a considerable distance on both sides the range, and round its northern termination, and to the quarries at the latter place, and also Castle Morton quarry, about two miles south of Little Malvern ;” to which may be added the loose masses in the ravine behind Great Malvern, and in that between North Hill and End Hill. It must be acknowledged that it is impossible to give to the rocks of these hills one general designation; but they appear to belong to sienite and the trap formation.. The differ- ence between sienite and greenstone consists only in the colour of the felspar. These rocks may, for the most part, be denomi- nated greenstone; often, however, they consist decidedly -of sienite, and sometimes may properly be termed sienitic green- stone; occasionally epidotic sienite. Whenever the felspar appears in any considerable mass, either in the form of a bed, or stratum, or of a vein, it is almost uniformly of a red colour, while in those in which that substance is in small grains (and is sometimes so small that the rock appears homogeneous), it is most commonly White, or of a greyish-white colour, more rarely red. The minerals of this range may be considered as being com- prehended in the following list : Crystalline hornblende may be considered as being the pre- vailing rock of these hills. Red felspar, often enclosing hornblende, sometimes mica, epidote, or calcareous spar; occasionally interstratified, and im veins, | An earthy substance, sometimes resembling lithomarge, but New Series, vou. 1. B v8 Mr. William: Phillips on Tan, » which appears to be hornblende in a peculiar state, probably in vthat 7 ee tig . , ues rt ..) Mica in veins and beds, enclosed in felspar, &e. Talc, enclosed in felspar, &c. | ©» Epidote, both compact and crystallized in’ veins, and: occa- esionally forming an integrant pe of the rock. es » Quartz, in veins, and imbedded in felspar. » . Heavy spar, in veins, &c. Magnetic iron ore. The rocks of this renee are for the most part, where they can ‘be’ seen above the surface, “confusedly heaped together ;” so “that, except in two places, which will presently be noticed more “particularly, no decisive appearances of stratification are to be edbserved, unless indeed we may be allowed to infer the exist- »ence of stratification wheresoever the hornblende rock assumes ~a@ slaty structure, indicating the direction of the dip; if this “inference be allowable, it may be assumed that stratification is “more common to these rocks than it appears at first sight. ‘The nearest place to Great Malvern at which a strong ten- “dency to regular stratification appears, is about three miles on the south of it, and about 100 yards beyond the stone which is inscribed “ Ledbury, four miles.” The beds here consist chiefly of red felspar, from an inch or less to a foot in thickness, “enclosing quartz and hornblende, rarely mica: the interstratified “substances are, hornblende, occasionally mixed with talc, and ‘sometimes including a thin layer of red felspar and quartz, or of impair antes hornblende greatly resembling mica, of which ‘the slaty structure is parallel with the beds of felspar: here and ‘there are layers of granular quartz, mica, felspar, and hornblende, ~the plates of the mica being parallel with the general dip of the ‘beds ; hornblende, sometimes of a slaty structure, occasionally eecurs in the same direction, but it now and then appears to ‘pass into ati earthy substance having somewhat the appearance of lithomarge. These beds vary from half an inch to a foot in thickness, and though not stratified with perfect regularity, are visible for nearly 100 feet in length, and 12 or 14 feet in height, above which the hill is covered with verdure. Many of the ‘beds may be traced for several feet. These beds dip at an angle of ‘about 20 degrees to the north-east. In this these beds are traversed by a dyke of green- stone, about two feet wide, except that it narrows a little about “¥8 inches above the road, and dipping nearly north, at an angle of about 70° with the horizon. he top of this dyke protrudes “above the beds it traverses, as is represented in the followin sketch, but it was not to be perceived that these beds were at all disarranged by it, the portions of them next to it not being ‘turned either upwards or downwards; nor did they seem to have suffered any alteration of texture or appearance where the con- ‘tact was complete. The greenstone of the dyke is so remark- 1821.) the Geology of the Malvern Hills. 19 ably fine-grained as to require the assistance of a glass to discover that it isa granular rock, and it lies in narrow layers running nearly parallel with the sides of the dyke, but which are traversed by crevices not quite at right angles, so.as to divide the layers into quadrangular masses, which, though hard, are so small and brittle as scarcely to afford a surface of a square inch from ablow by the hammer, This appeared to be the only instance of a true dyke or vein among the rocks of the range. Pursuing the road from Great Malvern towards Ledbury, the rocks on its side continue to present some, though less decided marks of stratification, until the road turns nearly due west; and just before it has attained the summit. of the rise, a quarr apeern on the top of the hill on the right, perhaps 100 feet above the road. This quarry is open to the south, and. here stratification is obvious from below. On. ascending it, the appearance is confirmed; stratification appears with nearly the same dip, but with much greater regularity than is apparent in the beds near the four-mile stone. The quarry is opened for upwards of 100 feet in length, and 40 feet.in height; and several beds of the red felspar, which is the prevailing substance, may ‘be traced very little short of the whole length, many of them upwards of 40 feet, dependent on the fall on the sides of the hill. he beds of felspar are thinnest near the summit; and the inter- stratified substances resemble those of the preceding instance, with some exceptions. Some of the upper, beds present inter- stratifications of felspar, hornblende, and mica (?) and enclose small masses of attractive iron; others of slaty hornblende mingled with quartz; others again of felspar and hornblende. One stratum, above three inches in thickness, consisting wholly of slaty hornblende greatly resembling mica, may be traced for about 40 feet in length along nearly the middle of the quarry. : In the front of the quarry, and so detached as to allowse passage behind them, whence the rock had been taken away, stood two enormous blocks, each not less than 20 feet m height, and 10 feet in other directions, of slaty hornblende, of which the schistose structure was parallel with the dip of the regular beds, which the summits of these blocks still supported. The upper parts of these masses, where their structure was most regular, contained thin layers of red felspar enclosing quartz3 these layers nearer the centre were less regular, and near the B2 20 Mr. William Phillips on [Jane bottom were quite irregular: the hornblende here assumed @ more crystalline structure ; and here, if not in most other places, the red felspar is not crystailine, but either compact, or ular. ali In several places on the eastern side of the range, and parti- _ cularly within a mile south of Great Malvern, many of the rocks in which hornblende greatly prevails, have that schistose struc- ture which has been mentioned as being parallel with the beds above described : here, however, if this structure is to be consi- dered as indicative of the direction of the strata, they will, for the most part, be nearly perpendicular to the horizon, but mostly with a slight inclination towards the north. In no other place , do marks so indicative of stratification appear. h The Wych affords an excellent opportunity of viewing the rocks of that part of the range: it exhibits a complete jumble of most of the rocks discovered in it, not without some appear- ances of stratification, which by due examination prove to be fallacious. . se 98 “ Granite, rarely presenting the same appearance as that of Alpine countries,—not decidedly crystalline, —in which sometimes the quartz, sometimes the mica, is wanting,” has been described as being the prevailing rock at the Wych, as constituting a great rt of End frit, and the upper part of North Hill, and Swinnit ill; but it is also acknowledged that ‘ the mere term granite would convey to most rdiinatilobtats an erroneous idea of the nature of these rocks.” An anxious search among these rocks ‘every where for more than three parts of the way along them southwards from their termination on the north, did not satisfy me that even a single hand-specimen of well-characterized granite could be found. Granite is commonly understood to be a rock, in which its ingredients, quartz, felspar, and mica, are all decidedly crystalline, without the appearance of one of them as an imbedding substance. In the “ granite” of this range, the felspar is invariably an imbedding substance, and compared with hornblende, is rarcly theimbedded substance ; it may be said rarely to contain either quartz or mica, although each is sometimes well defined, but never, as far as my observation goes, is unac- companied by hornblende. Hornblende is moreover the prevail- ing rock of the range. In the quarry on the side of the road to Ledbury, hornblende rock supports the stratified “ granite; ” and in Castle Morton quarry, on the eastern side of, the range, large blocks ofred felspar enclosing ‘qtiartz and’ calcareous spar, are imbedded in hornblende rock. These masses sometimes appeared like short thick veins crossing each other in various directions, of which the terminations wére mostly visible. It ‘appears, therefore, impossible ‘to’ consider this red felspar as a granite, and probable that the only reason why many, ifnot most of the projecting rocks of the range exhibit a considerable pro- portion of this“ granite,” is, that the hornblende by which it 1821.) the Geology of the Malvern Hills. 21 was heretofore flanked, and perhaps covered, has been. decom- osed and converted into the red earth, every where visible Beneath the verdure, and often to a considerable depth; and it is to this decomposition that we are to attribute not only the generally smooth surface of these hills, but also the existence of numerous masses of greenstone, sienite, and red felspar, in the valleys, on the sides of the hills, and which still remain in great quantity imbedded in the reddish earth: all these por- tions of rocks are still angular, without exhibiting any appear- ance of having suffered by attrition. - The alleged origin of this loose reddish earth seemed the more plausible from finding that the hornblende rocks, which were in a state of decomposition, yielded an earth of the same colour and appearance beneath the hammer. Near the summer house on e top of the ridge, west of Little Malvern, it contains portions of a rock which have greatly the appearance of mica slate, and also. masses of white quartz ; while on the western side, near the foot, columnar masses of sandstone mostly quandrangular, and sometimes a foot in length, and containing internal ochreous spots, are found in loose earth beneath the verdure. _. The foregoing facts, together with an examination of the pro- jecting rocks of the range, of the varieties of which some account is annexed, appear sufficient to induce the conclusion; that all are to be considered as sienitic, or belonging to the trap formation, but of a peculiar character. Annexed is a sketch of a mass of highly crystalline hornblende, about four feet long, and three feet in. other directions, which I ob- served lying in the valley between North Hill and End Hill. The ‘veins ” were of red felspar, enclos- ing hornblende. This sketch will serve as a fair specimen of the general directions of the “ granite veins ” of this range. In other masses, the veins were of epidote. Rocks of the Malvern Hills, and their principal Localities. Hornblende is the prevailing substance of the rock at Castle Morton quarry on the eastern side of Swinnit Hill. It is highly crystalline at that quarry, and sometimes contains roundish masses of calcareous spar, in other places specks of red felspar. It is sometimes traversed by red felspar in every possible direction, in veins which cannot be considered other than contemporaneous, from the 16th of an inch to a foot in thickness, and rarely of any considerable length, and often terminating abruptly. Thin veins of calcareous spar traverse the red felspar in various directions, striated con- trary to the run of the vein; it often contains hornblende; rarely mica. It is also the prevailing rock of the quarry at. 92 Mr. William Phillips on. [JAN - the northern part of the range. Hornblende rock passes into a “Substance of a durk vreen colour, imperfectly slaty texture, andearthy fracture, and of smooth surface, abounding at the Wych,” and having the appearance of forming a bed there: itis interstratified with beds of red felspar, a little south of the four mile-stone between Great Malvern and Ledbury, That hornblende passes into this substance will become manifest by the use of the hammer at the Wych. Greenstone and sienitic rocks, both large and small grained, abound on the sides of End Hill and North Hill, and occur on theirsummits. Very fine grained greenstone occurs in a columnar form, Likes readily parallel to two of its planes, and sometimes in-the form of an obtuse rhomboid, as near the summit of the Worcestershire Beacon, and on End Hill. A hard and somewhat schistose rock of horn- blende and felspar in minute grains occurs im situ on the western side of the range, south of the Worcestershire Beacon: on the eastern side, a little south of Great Mal- vern, are rocks of crystalline hornblende, enclosing specks. of red felspar and quartz, the mass being traversed by veins of epidote. Slaty horublende enclosing specks and larger. portions of felspar occurs at the Wych. ; Hornblende, reddish felspar, and quartz, “in small grains, constitute some of the rocks of End Hill and the summit of North Uill, and form ’a prevailing rock of these hills. It sometimes contains magnetic pyrites, veins of epidote, and sulphate of barytes.” Hornblende, felspar, quartz, and a little mica, “ constitute the rocks on the west side of End Hill; and on the side of the ‘road leading up to the Wych,” hornblende. prevails in. the. latter, and the rock is schistose. Hornblende, with a few spangles of mica, and a little felspar, - “on the ridge connecting North Hill and End Hill.” Hornblende and mica “are the constituents of rocks on the i of the hill between the Worcestershire Beacon and the ych,” Hornblende and mica, “ in a state of decomposition, mixed with red felspar; rocks of these constituents, and of a. slaty structure, occur on the north-east side of the Worcester- shire Beacon, and on the road leading from Great Malvern to St. Anne’s Well.” _ Hornblende and epidote, “ with specks of mica, and contain- ing veins of epidote, constitute rocks on the north side of End Hill.” Rocks of highly crystalline hornblende enclos- ing specks of red felspar and epidote (sometimes without the latter), are found in various places near the northern termimation of the range. ‘i Compact felspar, “of a pale flesh colour, is the prevailing f it NOSPLL Page 23. Yul Y iy “Le Z Yy:GG Uy i MTT ft i nt f MI A i : Ly bs LY; a a nH ii Hun A | AN HL HH | i i wat i : | (2 f ( 4, alZ, ‘ aside halle ‘ Prahttde’ i outie? Lepeedstone! Engraved for the Annals of Philosophy. Published by Baldwin, Oadock & Joy, Taruary 1.1621. 1$21:;] __ the, Geology of the: Malvern: Hills. 93: _xock onthe side of the road as it rises along the side.of the valley above Little Malvern, and ahs round the iE di _. face of the/Hereférdshire Beacon?” Felspar and quartz, with a little mica: naw vpulore; are de- seribed as. principally ee ate the: rece bis es western | side ofthe range.” . : : Compact felspar, hornblende, quaxte, and echibes ofan €rdhy. texture, imbedding detached crystals of. ci gh form a rock on the south side of Holly Bush Hill.” | Opaque quartz and silvery mica, “ in the form of a vein, occurs ___ on the side of the road leading up to the Wych.” . | Felspar and mica, “ united by a ferruginous: clay, as: far as the closeness of its texture would admit of decision, formed - a massive rock exposed on the south end of! the: ‘range, . called. Ragstone Hill bythe quarriers. . The rock is of an olive-green: colour, and is occasionally. traversed by veingy . of calcareous spar.” 130 Conglomerate, “ fine grained, of a- dark-brown. colour, and) ‘composed, of felspar, steatite, and calcareous spar, united “6 Dy) a ferro-argillaceous base, and containing some minute/ .\ specks, of a greenish yellow substance, in diverging fibres; _ . which is probably actinolite. . This, rock, whiab OCCUTS) Be short. way to the south of the Herefordshire Hencomy) attracts the magnet.” Conglomerate, of rounded masses and. crystals. of quartz, and - felspar, . with. some hornblende united. by an argillaceonse . —— in. the new road. lately made-on the side of North, i ArtTic.e III. An Account i a remarkable Stratum of Limestone, situated at Calder Side. ave a Plate.) ~ Tre stratum oF which, in’ the following pages I have endea- voured to give some account, is situated in the farm of Calder: _ Side, in the parish of Kilbride, about 10 miles to the south of. yee Sea and occurs in’ the position: noted in the following: ! Feet. Inches. Alluvial earth: ‘ Bituminous shale. _ Bastard ironstone, and’ redldish-black: bitum Ct iii MOMS... Meee ese gees. G29 Perforated stratum, to be idedertied:. 1.0 _ Very thin ‘stratum —— neddial-black schistus. re SPBU GR Taek d eee es HO SE 24 On a remarkable Stratum of Limestone, [Jaw. Feet. Inches. Intercepted stratum of quartz. Marly schistus, intermediate in colour between greenish-grey and yellowish-grey, and con- taining the charred remains of vegetables. 0 10- NS sate sakes sioie bee :6's 6 a .e.0g.m 8 his SERIRRAEL lal es BetamiNous Ogle. .:.5:.. +0 noice ocean tame ee), |S Bituminous shale, differing from the preceding in being filled with nodules of ironstone .. 11 = 1 Limestone. Schistus containing petrified entrochi, but no ironstone nodules. ...........-. pei Rapinlaiacs “emote Lime of considerable thickness, and wrought for the purposes of sale. These strata are laid open to view on the side of a steep bank overhanging the stream of the Calder, on Mr. Young’s property of Calder Side ; and a short distance further up the stream than Calder Wood, the seat of Sir W. Maxwell. ae The stratum of perforated limestone is the phenomenon which here attracts the notice of the naturalist. A representation of its appearance, as seen at Calder Side, is attempted in the sketch of the section of the strata (Pl. 1.) mentioned in the table, and I shall request your indulgence in my endeavours now to describe it at somewhat greater length. To account in a satisfactory manner for the formation of any’ stratum, or to explain the causes which have produced the most common geological appearances, are, perhaps, equally beyond. the power of human talent, as to account for the formation of the perforated stratum of Calder Side. For these reasons I shall endeavour to confine myself to a mere description of the appearance of this stratum, and avoid any speculations as to its origin. It must be owned.at the same time that while the common occurrence of many wonderful and inexplicable geolo- ea phenomena divest them in our eyes of the remarkable eatures which they in reality possess, that the imagination is almost irresistibly set at work, when so singular an appearance presents itself, as the one now under consideration. 7 . This stratum probably consists of millions of blocks resem-: rane those figured at fig. 2, for a great part of it is still covered, by the superincumbent strata of schistus, &c. When observed, in their natural positigri, these blocks are placed on end, their upper and lower ends‘forming the upper and under superficies of the stratum, which is here nearly in a horizontal position, and when first exposed by the removalof the superincumbent strata has the appearance of a payement similar to some parts of the Giant’s Causeway, from the ends of the blocks being so exactly fitted, and dovetailed into each other.. This pavement is, however, hollow, and a labyrinth of concealed apartments exists in its interior, for the blocks which at their extremities are nicely fitted ¥821.] 2 a situated at Calder Side. 25 into each other are worn away, as it were, at their centres into the form represented at fig. 2, and fig. 1, section of the perforated atratum, ° 5 10 78g (7 The hollow parts of the stratum are filled with a fine earth, which has much resemblance to Armenian bole, and is coloured with iron, being stained and streaked, of various tints of red, erange, and yellow. This fine earth is constantly moist, and as soon as it is exposed to the air, it becomes covered with a luxu- riant coating of vegetation, consisting of a minute species of conferva, whose thin roots, resembling the fibres of a spider's web, penetrate it in all directions. Such an appearance would have afforded matter of speculationto Duhamel and Henkel, and might have assisted these philosophers in their researches rela- ‘tive to what has been termed the equivocal generation of plants.* Have the diminutive seeds of these conferve remained concealed for ages, locked up in the interior ofa stratum of limestone, and buried beneath various strata of schistus and ironstone, and still retained the power of germinating as soon as exposed to the air of the atmosphere ? - The upper and under superficies of the perforated stratum are thickly covered with petrifactions consisting of a lesser variety of entrochi, and a quantity of shells. of the genus ostrea, the substance of which does not appear to have been much changed by the petrifying process. At the time when these shells became imbedded in their present situation, the animal inhabi- ting them could not have been alive, as tie valves are all of them found separate, and what is remarkable, those situated both on the upper and under superficies of the stratum have the interior superficies of the valve almost invariably turned towards the stratum. In the body of the blocks only a few entrochi, and none cf the bivalve shells occur. A few of the shells and some of the entrochi coat the surface of the intersticial vacui- ties. What a strange variety of causes must here have been called into action to produce the eifects to be observed here : on the upper and under superficies of the stratum we have petri- factions resembling each other in theirnature. In what may be termed the body of the stratum, we entirely want the more recent and perfect of these petrifactions ; viz. the bivalve shells, and have only a few of the entrochi. » The same law which seems first to have acted in the formation of the perforated stratum seems also to have exerted its influence, although only to a very limited extent, upon the superincumbent Strata of schistus and ironstone ; for these strata seem to show a tendency to separate into somethiag of a crystalline structure, as it were approaching to very imperfect basaltic columns in the direction of the lines A B C, fig. 1. If we could suppose that previous to the blocks composing _ * See Henkel’s Flora Saturnisans, chap. ii. p. 35 and 36. 26 On a remarkable Stratum of Limestone. [Sam the perforated stratum having assumed their present form, they had been detached into distinct crystals by some process similar to what basaltic columns owe their origin to, part of the raynteny might beconsidered as unriddled; for no accidental rocks coul have separated the stratum into these distinct blocks; but still the blocks becoming each of them thinner towards their centre is.to be explained. Could astream of water percolating through. the interstices have reduced them to this shape? I rather fear that the laws of hydraulics forbid such a supposition. The middle part only of each block is worn away ; both ends remain entire. Must we not, therefore, conclude that some extraordi- nary operation depending on chemical laws has at once formed each separate block into its present form? but here I must call, to recollection the inadequacy of such speculations to explain the subject of the present paper, and confine myself to a relation of facts. 288 Many years ago I had an opportunity of viewing from a short distance an appearance which, if my memory does not fail mey bore a considerable resemblance to the perforated stratum of Calder Side. It was what seemed to be a range of holes resem- bling in form the holes made by the Sand Martin (Hirundo; Riparia) in banks of sand, in which these birds construct their nests. ‘The holes which I allude to were situated in the’ front. of a steep rock overhanging the river Sotha, near the celebrated. falls of Trollhatta. It was in passing down the river in the dusk: of the evening that I saw them, so that I could not observe: whether the rock was stratified or not; and indeed I should probably not at all have remarked them had not the boatman who conveyed me down the river pointed them out to me, remarking at the same time that they were the residence of spirits; and that during the fine nights in autumn, a- bright light was seen-to issue from them. Most probably our ances- tors would at once have referred the perforated stratum of Calder’ Side to the times when various places in Scotland were peopled. by the fairies of popular superstition, and dated its origin at the hands of supernatural beings, and explained its uses as forming, the abode of the spirits of the wood, or ofthe flood. ~ _ Fig. 1, is a section of the strata at Calder Side. Fig. 2, two of the blocks composing the perforated stratum. é | of limestone, taken from their place, and seen in perspective as placed upon a wall near the spot. These-blocks consist of w wey be termed an argillaceous limestone of a bluish grey colour, o of a very slaty texture. It appears to contain much umen. , ve a . 1821.} - Action.of Chlorides and: Water. 27° ARTICLE IY. On the Action of Chlorides and Water. By Richard, Phillips, FRSE. FLS. &c. - DirFERENT opinions appear to be entertained by chemists of the greatest eminence and experience as to the changes effected | on those chlorides that are soluble in water by solution in it., On this, account I propose to state such opinions as I have found detailed on the subject, and I shall endeavour to collect the evidence which has been adduced in support of the different views entertained. ! The question to be solved may be thus stated: When a chlo- ride is dissolved in water, does it remain a chloride, or 1s it by decomposing water converted into a muriate ? It is further to be considered, whether the same explanation will apply to all the. aqueous solutions of chlorides. With respect to the non-metallic, chlorides, it is to be observed : that one of them, viz. chloride of azote, is insoluble in water, and consequently no change is effected in the properties of either compound. The chlorides of phosphorus and of sulphur on the. other hand act with great energy on water, and offer incon-. trovertible evidence that water in these cases suffers decompo- sition, for the products are such as do not combine with each. other, but exist in a state of mixture in the water, each possess- its peculiar properties. Thus when chloride of phosphorus. and water undergo mutual action, the oxygen of the water forms. phosphorous acid with the phosphorus, and the hydrogen unites with the chlorine to form muriatic acid. The perchloride of. phosphorus effecting similar decomposition yields phosphoric.: and muriatic acids ; and when chloride of sulphur and water undergo mutual decomposition, there are produced sulphurous, sulphuric, and muriatic acids. | ir H. Davy (Phil. Trans. 1810) observes, that “‘ when water is added in certain quantities to Libavius’s liquor, a solid crystal-. line mass is obtained, from which oxide of tin and muriate. of. ammonia can be obtained by ammonia. In this case, the oxy- gen may be conceived to be supplied to the tin, hydrogen to the oxymuriatic acid.” Inthe Phil. Trans, for 1810, he states more. distinctly that Libavius’s liquor is “ converted into a. muriate _ by water.” -In.his Elements of Chemical Philosophy, Sir H. Davy. has: been, in many instances, quite. explicit on this point ; and. his. opinions are favourable to the idea that. chlorides become. muriates by being dissolved in water. Thus he states that the: perchloride of iron “ acts with violence upon water, and forms, a.solution of red muriate. of iron ;” and he. observes that the. protomuriate “ forms a solution.of green muriate of iron by ite: action upon water.” 28° Mr. Richard Phillips on the [Jan. In Dr. Thomson’s System of Chemistry, I do not meet with any detailed opinion on the subject. He states, however, that “chloride of antimony is decomposed when mixed with water, white oxide of antimony, and muriatic acid, being formed.”— (Vol. i. p. 584.) In treating of the muriates generally, he refers them to the chlorides, and of muriate of barytes he says, “ this salt likewise will be found under the name of chloride of ‘barium ;” and he states that the “ crystals of chloride gradually deposit.” From this it would appear that the crystalline salt usually termed muriate of barytes is considered by Dr. Thomson to be a chloride ; and in the Annals for November last he consi- ders chloride of barium as converted into muriate of barytes by -solution in water. Mr. Brande in his Manual (p. 174), describing the properties of metallic chlorides, observes, that “‘some are soluble, others insoluble, in water. Several of them decompose water, giving rise to the formation of muriatic acid and an oxide; or in some cases to a muriate.” Mr. Brande has not, I think, pointed out instances of the production of these different effects, but from his stating that chloride of potassium dissolves without decom- position in water, it would appear that he considers it to remain a chloride in solution. Mr. Brande, however, states distinctl that “when chloride of manganese is dissolved in water, it produces muriate of manganese.” The chloride and perchloride of iron produce also he admits muriate and permuriate of iron when acted upon by water, and he allows similar decomposition of water, and the consequent formation of oxide and muriatic acid, to the chlorides of zinc, tin, copper, and antimony. M. Thenard in the first edition of his Traité de Chimie (1816) states, without any reserve, that “ all chlorurets, when dissolv- ing in water, decompose it, and become hydrochlorates : they thus effect the decomposition of water in the same way as the iodurets, and the two principles of the water, the oxygen and the hydrogen, unite ; the first with the metal, and the second with the chlorine.” In the second edition of this work (1817), M. Thenard maintains the same opinion: he states, however, several of the difficulties which attend both opinions. M. Gay-Lussac, on the other hand, in his memoir on iodine 4{Annals, vol. v. p. 125), observes, “‘ We ought then to admit it as a certain fact, that the muriates are all changed into chloru- rets, when melted, or even when dried, and some of them even by being crystallized. We may suppose, as we have done for the’ iodurets, that the chlorurets dissolve in water without. undergoing decomposition, and that when we unite hydrochloric | acid with an oxide, the hydrogen of the acid, and the oxygen of the oxide form water. hether this be the case or not, nothing but chlorurets exist at a red heat.” In subsequent parts of the same memoir, M. Gay-Lussac says, “I believe that according t6 the nature of the substance with which the chlorine is com- bined, the chlorurets may dissolve in water without undergomg™ 1821.] Action of Chlorides.and Water. 29 decomposition, or being changed into hydrochlorates. during that solution.” He further states, “ | admit as a principle that we ought to have a chloruret or a hydrochlorate in solution, according to the forces which act in order to decompose water are greater or less than those which keep its elements united.” _. In attempting to elucidate this as well as every other subject, it will be better to begin with those cases which are too obvious to admit of question, and proceed to those which are more obscure. There are some cases of the action of water upon chlorides which prove, | think, incontestably the decomposition of the water, and the union of its oxygen with the metal, and its hydrogen with the chlorine—I mean the effects observed. when the chloride of bismuth and of antimony are acted upon. It is quite evident that oxides of these metals are precipitated,. and that muriatic acid remains in solution. It will be unques- tionably admitted, whether we dissolve a metallic oxide in muriatic acid, or take the dry compound which remains after evaporating such solution, and exposing it to a red heat, and dissolve it in water, that the solutions obtained are in all respects similar. Thus when we dissolve peroxide of iron in muriatic acid, we obtain a red coloured solution; and a similar effect is produced, if we dissolve the perchloride of iron in water. Both solutions it will be admitted contain either chlorides o ‘Imuriates. | When iron is put into dilute muriatic acid, it is well known that hydrogen.gas is evolved, and the iron dissolved. Now if we conceive this solution to contain chloride of iron, we must sup- pose that the hydrogen evolved is derived from the decomposi- tion of the muriatic acid, and not of the water; and as we obtain a similar solution by dissolving protoxide of iron in muriatic acid, we must suppose that the oxygen of the oxide unites with the hydrogen of the muriate acid, that water is formed, and chloride of iron remains in solution. I say we must admit the evolution of hydrogen from the decomposition of the muriatic ‘acid in the first case, or we must make the improbable suppo- sition that iron, while dissolving, decomposes water to receive oxygen from hydrogen, and that immediately afterwards it yields the oxygen to the hydrogen of the muriatic acid, and thus produces chloride of iron. , otortye From these considerations, I think it will involve fewer diffi- culties to consider this solution as containing a muriate rather than a chloride. We have in. this case only to admit, as-is indeed generally allowed, that the hydrogen is evolved from the decomposition of the water, and not of the acid; and when the oxide of iron is dissolved in liquid muriatic acid, we must con- sider that the oxygen of the oxide and the hydrogen of the acid do not form water, but remain combined, the first with the iron, sand the hydrogen with the chlorine. RRO 30 Mr. Richard Phillips on the . [Tan. There -are other considerations which tend to strengthen the opinion that the chlorides of iron become muriates by decompos- Pa dissolving im'water. If to these solutions we add‘ an ivas potash or soda, oxide of iron is precipitated. Now we must either admit that oxygen is transferred from the alkaline oxide to the iron, which is a possible case, that the iron pre- eviously existed in the state of oxide, or that by some operation ‘similar to: that which has been called predisposing affinity, the decomposition of water is effected at the moment of the presen- tation of potash to chloride of iron. As ammonia contains no oxygen, and as it decomposes solu- tions of iron as readily as potash, the cases are reduced to two, viz. either that the iron exists in the state of oxide, or that it becomes ‘so by the intermediate action of the ammonia. It on to me that the first is the most probable case, although, as I shall presently notice, the latter is a possible one. Among ‘the reasons which may be advanced for supposing the solution to contain a muriate are the facts already adverted to of the decomposition of chloride of antimony by water ; another reason is that that there are some acids which form insoluble compounds with the oxide of iron, such as the phosphoric, for example. If then we add a solution of phosphate of soda to a solution of muriate or chloride of iron, phosphate of iron is precipitated, which consists of the acid united to oxide of iron, and we are, itherefore, reduced either to admit that the iron exists in the state of oxide, or that chloride of iron decomposes water by the addition of a solution of phosphate of soda, for which there appears to be no sufficient cause, nor do I recollect the occur- rence of any such case. sc The action of water upon the chlorides of potassium, sodium, barium, &c. does not appear to have been more decided upon by chemists than other chlorides. Dr. Thomson, as I have already noticed, considers that chloride of barium by solution in water becomes a muriate; whereas M. Gay-Lussac, in a note to a memoir I have already alluded to, says, “ On mixing solutions of chloruret of calcium and sulphate of ammonia nearly in equal volumes, the temperature scarcely rose one degree of Fahrenheit, ‘though such a quantity of sulphate of lime was formed that the whole mixture became solid. The solution of chloruret of barium treated in the same way produced an elevation of about 6°3°. From these it would seem that in the solution of chloruret of calcium, the metal is in the state of an oxide, while in that of chloruret of barium the metal is still in the metallic state.” With Fo to the chloride of barium, I am certainly much more mclined to adopt the opinion of Dr. Thomson than of M. Gay- ‘Lussac ; for it appears to me extremely difficult to discover by -what kind of action water is decomposed when sulphate of soda, for example, is added in solution of chloride af barium, and ‘TS821.] Action of Chlorides and Water. ‘31 ‘indeed this very decomposition on this principle must, I think, “prove fatal to what seems to be M. Gay-Lussac’s opinion that ‘chloride of sodium is not decomposed by water. If this latter supposition be true, then, when sulphate of soda and muriate of barytes suffer mutual decomposition, the muriate of soda which is formed must exist as such only for a moment, and watér must be recomposed to form the chloride he supposes to exist. ‘That the different temperatures which are occasioned by dis- ‘solving certain chlorides in water cannot, | think, be deemed a ‘eriterion’ for determining the question may be inferred from a ‘very ingenious paper, contained in vol. xii. p. 42, of the Annales ide Chimie. In this memoir, upon the analysis of mixtures of the-chlorides of potassium and sodium, it is stated that under ‘similar circumstances a given weight of chloride of. potassium sinks Fahrenheit’s thermometer 20°52°, and the same quantity ‘of chloride of sodium depresses it under the same circumstances “only 3°42°. Now it can, I think, hardly be supposed that bodies ‘so similar in their affinity for oxygen, as potassium and sodium, should ‘differ in their action on water when combined with chlo- ‘rine. We may consider these chlorides and that of barium as ‘converted into muriates by solution. With respect to the chloride of potassium and sodium, there are other reasons for believing them to be converted into mu- tiates by solution in water.. In the first place, these metals have strong affinity for the oxygen of water, and so also has the chlorine for its hydrogen, becoming muriatic acid when its aqueous solution 1s exposed to the solar light. As, however, chlorine and these metals have also great affinity for each other, it is certainly possible that this mutual affinity may diminish or destroy their separate attraction for hydrogen and oxygen. It _-must be granted, as before noticed, that whether we dissolve ‘dry chlorides in water, or saturate liquid muriatic acid with metallic oxides, that similar solutions are produced. If to the solutions of chloride of sodium or potassium we add sulphuric acid, their respective sulphates are formed, and a similar effect, mutatis mutandis, is produced when tartaric acid is used with the solution of potash. . Now in these operations, one of two cases must occur. Supposing we have dissolved potash in muriatic acid, and the result to be solution of chloride of potassium, water must have been formed, we then add tartaric acid, and this possesses the power of so acting upon the elements of the solution that water is again decomposed, and muriatic acid and potash ‘again result, ‘as is evident by examining the solution and the crystalline cepa of the bitartrate of potash. _ Phe other case is simply this; viz. that the chloride of potas- slum immediately decomposes water, and then there is no ne- cessity for attributing this power to the intervention of the sul- phuric or tartaric acid. } 32 _ On the Action of Chlorides and. Water. (Jan. _ There is one case which I have already hinted: at which ‘appears to me difficult of explanation upon any supposition. When chloride of mercury is put into water, as already noticed, neither solution nor action takes place : if we add potash to the mixture, protoxide of mercury is immediately precipitated. Now in this case it would certainly appear to be most probable that the oxygen is supplied by the potash, the chloride of potassium we remaining as such in solution. If, however, we substi- tute ammonia for potash, still the decomposition is effected, muriate of ammonia is formed, and protoxide of mercury pre- cipitated. In this case it would seem that water is decom- posed by the intervention of ammonia ; for not containing any oxygen, it cannot yield it, as the patate may be supposed to do. It is difficult, I think, to explain this action, and on this account I am far from denying the possibility of tartaric acid to effect that decomposition of water which may be supposed to occur when it acts upon chlorine, potassium, and water. — Certainly what ammonia appears to do in the case of chloride of mercury, tartaric acid may effect in that of chloride of potassium. : In vol. vi. p. 185, ofthe Anna/s, M. Gay-Lussac says, “When a solution of chloruret of calcium (which he supposes to exist in solution as such) is mixed with subcarbonate of ammonia, the chlorine must pass to the state of hydrochloric acid, in order to combine with the ammonia ; ” and further on, he observes, ‘ It is the difference of solubility of subcarbonate of lime and hydro- ‘chlorate of ammonia, which occasions the double exchange of the bases and acids ; and consequently it is on account of that difference of solubility that water is decomposed.” g Now with much deference I think this reasoning can scarcely be admitted. Surely the insolubility of carbonate of lime cannot act until the carbonate exists, and the decomposition, for which this insolubility is adduced to account, must occur before it. If, however, the kind of reasoning employed by M. Gay-Lussac is admitted, then we may certainly account for the decomposition of. chloride of mercury, by supposing that it results from the affinity of uncreated muriatic acid for ammonia. | '_, After having considered the subject (I confess with much less attention than the intricacy of it requires), I incline to ‘the opinion that all soluble chlorides are converted into muriates — by solution in water. I think it will appear, from what I have stated, that fewer decompositions must be supposed to oceur on ‘this supposition than the other; and it is to be recollected, in support of this opinion, that no objection, as far as I know, has been ‘made aint the idea of the decomposition of water as it respects sulphuret of pomen, or rather potassium. Admitting (what, however, I am by no means disposed to assert) that the opinion which I have adopted to is most proba- ble, the question still remains to be decided, under what point of view shall we regard those chlorides, or muriates, which 1821.] On Two late Attempts to ascend Mont Blanc. 33 contain water of” crystallization. Are they in their crystalline state chlorides or muriates? I certainly in this case also incline” to the opinion that they are to be regarded as muriates. This idea is much strengthened by the following passage from Dr. Thomson’s paper, on the “ True Weights of the Atoms CY Barytes, Potash, &c.” (Annals, vol. xvi. p. 331), “ When crys- tallized muriate of barytes is exposed to a red heat in a platinum crucible, it loses all its water of crystallization ; while at the same time the hydrogen of the muriatic acid unites with the oxygen of the barytes, and flies off in the state of water.” ARTICLE V. Brtract from “ An Account of Two late Attempts to ascend Mont-Blanc, by Dr. Hamel, Counsellor of State to his Majesty the Emperor of all the Russias.” Most of our readers are probanly. aware that during the last summer an attempt was made by Dr. Hamel, in company with several other persons, to reach the summit of Mont Blanc: it i¢ equally well known that during the journey, the whcle party was in the most imminent danger, and that some of the guides actually lost their lives. It is presumed that. the particulars oF this fatal expedition, taken from the Bibliotheque Universelle published in August last, will be acceptable to the readers of the Annals. | The first of the two attempts of which an account is given was undertaken on August 3, the anniversary of the ascent of M. de Saussure. Dr. Hamel, in passing by the baths of St. Ger- vais, heard that two persons of the country had reached the summit of Mont Blanc, and descended the same day at Prarion, | whence they had set out. This report made Dr. Hamef desirous of attempting this new route, which, according to the account given of it, was less difficult, and dangerous, and much shorter, than that by Chamouny, which, since Saussure’s © time, had always been followed. } It appears that the same persons who had already ascended by this route proposed again to undertake it, in order to remove some doubts which had been entertained at Chamouny with respect to the practicability of the journey. With these persons and the Curates of St. Gervais, and St. Nicolas de Verosse, the attempt was made by Dr. Hamel. _ In order to insure success, it was proposed to effect the ascent in two days, passing the night near la Pierre Ronde, the name given to some rocks situated beneath L’Aiguille du Gouté, and at half-past seven, the travellers halted to pass the night, shel- N.S. vou. 1 | c -- DreHamel’s Account of.) Tv tered by the rocks, and not far from.a torrent coming*from the Glacier de Bionnassay,. ; » The night was beautiful, and at half past two in the:morning; the journey was resumed by moon-light, and at 22 minutes after five o’clock, the travellers reached the base of the Aiguille «du Gouté; and afier about three hours of very difficult. ascent among loose stones, the summit of the Aigdeilliovnie attained at 50: minutes after eight; the height of which is upwards’ of 12;000 feet. After taking rest, and adopting precautions against the cold, and the rays of the sun reflected by the snow, they set off at a quarter past nine towards the Dome du Gouté, and arrived at the summit at half past 11. | i The height of this is 1330 [13,500] feet, and Dr. Hamel could advance but few steps without waiting to take breath, on account of the rarity ofthe air; and finding, from the state of exhaustion he was in, that he must have staid at least half an hour before he could resume his journey towards the summit of Mont Blane, and calculating that it would be impossible to,come back to the Aiguille du Gouté before night, he resolved to return by the route by which he had ascended, without attaining his object. The déscent is represented as more difficult and dangerous even than the ascent, but it was safely performed, and the party arrived at about nine at night at an inn called Pavillon de Bellevue, sis tuate on the Montagne de la Chaletta between Mont Lacha and Mont Prarion. , f '’ Having given a sketch of Dr. Hamel’s account of his first attempt to ascend: Mort Blanc, I shall continue nearly in his own Words the account of his second journey, and which was attended with great danger to the whole party, and proved fatal to some of the guides. & le | -)€ Tn looking over M,de Saussure’s work, I found that he had tried this same route ; but the dangers which he encountered in _ the ridges of l’Aiguille du Gouté prevented him from proceeding farther : he did not even arrive at its summit. - “This induced me to believe thatthe route by Chamouny, by which he afterwards ascended, must be at least as convemient’s and [ wished to meet with an opportunity of trying it, so that I might decide which of the two routes was preferable. Ta idathee “Soon afterwards, I learned ‘that some persons at Geneva Weré also desirous of ascending Mont Blanc: one of them was. M. Selligue, a mineralogist and mechanical artist. , He informed me that he had invented a barometer upon an entirely new prin- ciple, which he wished to try on these mountains. “* As the claim of Mont Blane to be considered the highest mountain of Europe has been lately disputed, and as no travel- ' lets who have ascended it since M.de Saussure have taken the. trouble to measure it again, 1 wished to determine its height, with the assistance cf several barometers. Prof. de Saussure’ had the goodness to lend me an excellent walking-stick baro- 1821] Two late Atiemptsto'ascend Mont Blanc. 3h meter, made at Turm. The reservoir for the mercury. is a'glass cylinder, and the level is’ regulated by. a, screw. and. pistony M: Selligue: constructed a syphon barometer ; and in case these, two barometers should be deranged in. ascending, I filled. with: mercury, two glass tubes 18 or 20 inches in length, and bent. at, one end like a syphon. The, mercury. having. been boiled, [. closed the opening, so that no. variation in the volume of the, mercury might: cause air to enter the longer leg of the syphon. Qa arriving at any height, [ had only to remove the cork, and: allow: part of the mercury to come out, and then to measure the. height of the column standing -in the tube. [ had, thus foar, barometrical instruments to measure the height of the:summit. ~ © In my first ascent I was surprised at the action, which the, sun’s rays had upon the skin; and | intended to make some, experiments on the power of these rays concentrated by lenses, Col. Beaufoy had previously paid some attention to this subject,: and I think, as he does, that these experiments may, become: interesting in the theory of light and heat. Y *« | purposed also to make observations upon myself and my: companions as to the effects of rarefied air, upon animal. organi-. zation ; and after what I had already observed during. my first ascent, [ flattered myself that I should obtain. results. which would be useful in physiology, | . ] procuredia bottle of lime-water to determine the presence,, and by approximation, the quantity of carbonic acid. in, these, élevated regions, and to discover whether air which had, been, respited contained the same quantity of carbonic acid as it does, inothose regions in which ‘at each inspiration. one-third more oxygen enters in the same volume of atmospheric air. I intended, also, when high up, to bleed some animal, in order to observe by the colour of the blood whether it was or was not sufficiently, _decarbonized, | »T filled four bottles with spirit of wine, which, when poured wpon/a sponge, was intended to. be used for combustion ; and I proposed to bring back some of the air of the summit in these bottles for analysis. A Papin’s digester, of very simple construction, was intended to prove the possibility of cooking meat at great heights. The monks of the Grand St. Bernard complain that they are unable to dress their food sufficiently. The reason of it is, that water in large open vessels, being less compressed by the atmo- Sphere at great heights than in plains, boils at a lower tempera- ture. A separate apparatus was prepared to measure the exact | temperature at which water boils at different heights. “A ‘small table, with a camera lucida, was furnished by, M. Selligue, to sketch a panorama from the summit of Mont Blane, © Prof. Pictet supplied me with the instruments requisite to Observe and measure the temperature, the electricity, and the moisture of the atmosphere, Kc. &c. | c2 o 36 Dr. Hamel’s Account of x [Jan *“ Mr. Joseph Dornford, and Mr. Gilbert Henderson, two. English gentlemen, and both of the University of Oxford, were anxious to join us ; the former of them had, when in England, formed the project of ascending Mont Blanc. We set out on Aug. 16, at three o’clock in the afternoon from Geneva for Cha- mouny. We arrived the next day at le Prieuré, reaching the. excellent hotel de l’Union, oa by M. Charlet, at two o’clock, “We applied to Joseph-Marie Coutet et Mathieu, son of Pierre Balmat, whom M. Pictet had recommended to’ us as ides who were equally robust and trusty. They advised us to. take 12 guides, or three for each traveller. e referred the choice to them; and our obliging hostess undertook to prepare all that was necessary for the journey. The next morning at a ede past five o’clock, we set out in the finest possible weather. e went at first in the direction of the Glacier des Bossons,) but before we reached it, we turned to the left, and began the) ascent in a forest. At seven o’clock, we had got above the» forest, and reached the chalet, inhabited by Pierre Frangois: Favret, formerly one of Saussure’s guides, who had ascended, and his son was with us. “* Here one of our guides, Julien Devouassou, son-in-law of - D. Paccard, was nearly poisoned. He supposed that he had. bought some syrup of vinegar at Chamouny ; and arriving at a stream, he tried the syrup before he mixed it with water: ‘he swallowed a little of it. It was concentrated sulphuric acid,. which burned his stomach and mouth in a terrible manner. His sufferings were great, and he vomited much. Fortunately this. accident happened near a chalet, where I found some wood ashes, and these I made him swallow mixed with water; the alkali neutralized the acid instantaneously, and the guide having — recovered, continued the journey with us. _ “ From the chalet, the ascent is continued zig-zag in the direction of the Aiguille du Midi; at half-past eight, we rested at Ja Pierre-pointue, where the mountain projects between the Glacier des Boiisdus and the Glacier des Pelerins, but nearest the former. From hence the summit of Mont Blanc is for — the first time visible, and le Prieuré is still in sight. From thence we turned a little to the right, and at nine o’clock we crossed the torrent called l’eau noir, but which, instead of water, was filled with enormous blocks of granite, rolled down from above : the Aiguille de la Tour is on the left. A quarter of an hour afterwards, we passed to Nant Blane; and at a quarter before 10 o’clock we halted to breakfast round a great stone between the Glacier des Bossons and Mount Basselache. The geides call it ‘la pierre’ de l’echclle,” because they. usually _keave the ladder there which is used to cross the Glaciers’ At 10 isinutes past 11 o’clock we recommenced our journey, and in five minutes we reached the Glacier des Bossons, which must be crossed obliquely in the direction of the Grand Mulet. Ata 1821.] Two late Attempts to ascend Mont Blanc, 37. hundred paces from the edge of the Glacier wonders begin which no pen can describe. At every moment we stopped to make each other observe some striking co.figuration of the ice; we heard nothing but ‘ Look to the right! Look to the left!” ‘Sometimes it was a bottomless precipice; at others a tower of ice more than 100 feet in height. The ladder was soon required. ‘How were we to cross a crevice of 20 feet wide, apparently bot- tomless, longitudinally divided into two by a thin wall of ice, scarcely a foot thick, and 10 feet lower than the sides of the crevice which it divides? Arrived at the brink the ladder is Jowered and supported upon the thin wall of ice in the middle of the crevice. One of the guides descends ; the first traveller follows, and keeps himself upright near the ladder. on the wall of -ice, one foot broad, or sup; orted by his stick, he stands immoy- ‘able, and endeavours to shun the sight of the two blue gulphs ready to swallow him on the least loss of equilibrium. The guide then rests the top of the ladder against the opposite edge sof the crevice, and the traveller having mounted it, it is again returned to the first brink in order to let the second traveller edescend, and so on with the remainder. When the ladder is ‘some inches longer than the crevice is wide, itis placed across it like a bridge; and every one goes over on his hands and sknees. Sometimes there are crevices which are covered by bridges of snow which are often narrow. Sometimes those who / walk last find these bridges penetrated by a foot which has pre- _ceded them, and it is then necessary to turn the foot a little aside. : . “‘ In spite of all the difficulties and dangers, we crossed the Glacier without the least accident. At a quarter past one we were above the junction of the Glacier des Bossons. with the Glacier de Tacconay, and between these two occurs the Mon- _tagne de la Cote; and after having ascended a ridge of snow, ‘imelined at an angle of 56°, at precisely three o’clock, we set foot on the base of the Grand Mulet on the western side. These erocks, which project from the middle of the ice, are not more firm than those of the Aiguille du Gouté; and we ascended -them so slowly that it was half-past four when we arrived at the: highest part of the Grand Mulet. A black cloud which formed ‘in the west decided us to stay here for the night. The summit. of this rock having the form of the letter L; that is to say, ofa right angle, our ladder and-some. sticks covered with cloth were. “So arranged as to form the hypothenuse. A little straw scattered. upon the horizontal part of the rock was the mattrass upon. al we lay down side by side. We were hardly covered when it began to rain; and soon after the thunder was heard majestically around us. I had scarcely attempted to put the point of the electrometer out of our tent, when its two balls began to move with so much violence that I was alarmed. The whole of the night’ was stormy. The next morning the rain 38 | Dr. Hamel’s Account of “[Tan. eeasedy and the air was so pure that we saw the lake of Geneva, and some more distant objects, very distinctly. | , “© We hoped that towards noon the ‘weather would clear-up, but it remained uncertain, and we resolved then to bivonac ‘gain the following night in our tent a la Cossaque. Coutetsent two of our men to Le Prieuré to procure a supply of provisions for the guides. At/intervals, | occupied myself ‘with reboiling the mercury of one of my barometer tabes, which had been injured on the journey. ‘We tried the temperatere of boiling water, and found it to be 162° of Fahrenheit. . I made arrange- ments to let off some fire-works on returning from the summit, for I was curious to try whether the fire-works would rise wellin ‘this rare air. J had balls and shining ‘stars prepared with arsenic. I had also Bengal fire prepared with antimony; and, besides, a mixture of nitre, sulphur, and orpiment, in order.to. ‘¢ry. to illuminate all the summit of Mont Blanc, and the spires.o the*strrounding mountains. i «* At five o’clock some hail fell, and until midnight the weather “was Cloudy; but on the 20th, at one inthe morning, the heavens “appeared studded with stars, although the valley was still hidden by fog. Coutet went out to observe the weather, and informed ‘usithat it promised well, but that it would be prudent still :to wait va little befure we decided upon ascending. -At about five «clock, the summit was lighted by the sun; the air perfectly “serene and calm. Our guides informed us that ‘ve mi ht begm sour journey.’ M. Selligue, who had been for some time unwell, and who feared the return of the rain before the close of day, none staying at the Grand Mulet. Two of our guides who Shad never ascended Mont. Blanc, and whom Coutet wished to ‘remain with M. Selligue, refused to do so. The weather was -favourable, and everyone was desirous of ascending. Atlength two other guides consented to stay behind. » Messrs. Dornford, ' “Henderson, and I, with eight guides, set out from the Grand *Mulet at 20 minutes past five ; the thermometer was at 34° of “Fahrenheit. Having entered upon the snows ‘which were here “yather deep, we went immediately towards the Aiguille du Gouté, “afterwards we ascended towards the summit, and almost al- “ways in a zig-zag direction, in order to avoid the. crevices and “Steep acclivities ; and at a quarter before seven, the summit ‘reappeared on this side” The weather was beautiful ; and, very ‘far beneath us, we saw white clouds, like a calm sea, penetrated ‘here and there by the: summits of the highest mountains, the ‘names of which were mentioned by Coutet, les Fours, |’ Aiguille ‘de Varens, le Buet, le Dent du Midi, le Dent de Morcle, &c. “At about seven o’clock these clouds ‘began to disperse, and ‘we ‘perceived le Prieuré. As we continued to ascend, we found’the ‘snow harder, and not'so deep. No snow seemed to have fallen ‘an these higher parts for some time. ae At 20 minutes past seven we reached the first of three plat- 1821.) Two late Attempts to.ascend Mont Blanc. 89 forms of snow, which:occur in the space between the Domerdu Gouté and Mont Maudit, the eastern shoulder of Mont Blane.., After having crossed this first platform, at a quarter before eight, we ascended an acclivity at an angle of 25°. or 30°. This leads ‘ito the second, ‘which we began to cross at 10 minutes past eight, having thenon our right hand the great seracs* of ice, avhich are: visible even at Chamouny.. The sky, when observed mear; these white masses of ice, appears of an extremely deep- -blue: colour; indeedalmost black. After having ascended yanother steep acclivity, we reached, at half-past eight, the Jast ofithe great platforms, bounded on the right:by the highest: part of the Dome, on the left, by the last rocks on this side, and on athe south side by a steep acclivity, at about the height of which, sand a little further, appears the summit of Mont Blanc. Here sour guides congratulated us, telling us that all difficulties wete yactually' overcome; there were no: more :crevices,))no more dangers. Never, said they, did an ascent succeed better; no sone ever ascended) more rapidly, and with less difficulty. In fact, the snow had precisely the degree of hardness whichis desirable for walking upon with ease : the feet. did not sink ‘too -much, and the snow was not too hard. We had nevertheless for some time experienced the effects of the rarity of the aim: amy pulse beat 123 in a minute, and | was continually thirsty. Our guides advised us to breakfast here, for, said they, higher up you will have no appetite. A cloth was spread upon the isnow at the entrance of the great platform, which served both -for chairs and table. Every one eat his half chicken with appe- ‘tite. l-arranged several things for the observations and experi- aents which 1 proposed:to make on the summit. 1 wrote two motes:'to announce our arrival at the summit, leaving a:blank merely to:insert the hour. intended to fasten them to a pigeon ‘which [-had: with me, and which I intended to liberate on the ‘summit, in order to observe how he would fly in this rare atmo- sphere ; and afterwards. to know if he would find his way ‘to Sallenche, where the female was. We kept:a bottle of .our ‘best wine in:order to:drink to the: memory of de Saussure on the summit.) - ot At precisely nine 0’c:ock, we set off to-ascend the summit, ‘which we ‘saw before us. ‘Would you accept a thousand ‘pounds to descend instead of ascending?” ;said one of my ‘companions to his fellow countrymen. ‘1 would not return forvany money,” was the reply. We were all full of hope and’ joy at seeing ourselves so near the end of our journey. The ‘beautiful weather, the calm which reigned around us, the celes- dial-air which we had breathed during our repast, made impreés- *stons ‘upon our minds which are not experienced in lower regions. * Scracs are those’parallelopipeds, cubes, and other rather regular forms of ice and ‘show which are found at great heights. ‘The name is derived from a kind of white p eadiniare in ‘the mountains, ’-and ‘to which similar forms are given. 40 © Dr, Hamel’s Account of © Jan. saw myself already on the summit. I took a specimen of the Ahighest rock in Europe to place it in the Imperial Mineralogical Cabinet at St. Petersburgh. I intended some for the museum _ ‘at Geneva, and other collections. ! 1 OW ** We crossed the great platform of snow, at the entrance of which we had breakfasted. While crossing, I had occasion to ‘wemain for some time rather behind, and it was near the angle on the right that | rejoined the company. We ascended about thalf the height of the great acclivity of snow, which, exterding ‘the whole length of the platform, rises towards the summit of ‘Mont Blanc. As, however, between this acclivity and the summit there are ridges of ice which are almost vertical, it is mecessary to cross the acclivity horizontally, by keeping to the deft, in order to reach the last great rocks at the height of "14,700 feet from which Italy is visible. From these rocks, b turning to the right, the summit is ascended, at the height of ‘960 feet. We walked one after the other, for it is preferable to ‘tread in the footsteps of the first guide, who, on account of the fatigue which he suffers, is changed from time to time. « “We advanced thus in a nearly horizontal line, crossing the vacclivity about half way up; that is to say, at almost equal dis- tances between the ridges on our right, and the platform of snow sapon our left. No one spoke, for at this height even talking is fatiguing, and the air conveys sound but faintly. I wasstill the dast, and-after taking a dozen steps, supported by my stick, I stopped to make 15 inspirations. 1 found that in this manner I could advance without exhaustion. Prepared with green spec- -tacles, and with crape before the face, my eyes were fixed upon amy steps, which I counted. Suddenly I felt the snow give way under my feet. Thinking that 1 merely slipped, I thrust my stick to the left, but in vain. The snow, which accumulated on my right, overturned and covered me; and I felt myself forced downwards with irresistible power. I thought at first that I was the only one who suffered this accident, but feeling the snow ‘accumulate upon me so as almost to prevent my breathing, I ‘imagined that a great avalanche was descending from Mont Blanc, and forcing the snow before it. Every moment I expected to be deiiabiod by this mass : while descending I turned over repeatedly, and I strove with my strength to divide the snow with my arms, in which | was buried and struggling. I succeeded at last in getting my head out, and I saw that a great part of the acclivity was moving; but as I found myself near the edge of this slippery part, I made every effort to get upon the hard snow, where | might at last find footing. It was not until then that | knew the extent of the danger; for I saw myself near a erevice which terminated the acclivity, and separated it from the platform. At the same moment I saw Mr. Henderson’s head still nearer this abyss. I discovered still further Mr. Dorn- ford and three guides, but the five others did not appear, I 1821.] Two late Attempts to ascend Mont Blanc. 41 - choped still to see them come out of the snow which had stopped, but. Mathieu Balmat cried out that there were still persons in the erevice. I will not attempt to paint what then passed in my mind. I saw Mr. Dornford throw himself upon .the snow in ‘despair, and Mr. Henderson was in a condition which made me fear for the consequences. But our consolation may be judged of when, some minutes afterwards, we saw one of the guides «come out of the crevice; our hurres redoubled at the appear- vance of the second; and we yet hoped that the three others -would also reappear, but, alas! they were seen no more. The guides, fearing a second slipping of the snow, directed eas to remove to a distance, but that was impossible. Mr. Dorn-— ford declared that he was ready to sacrifice his life to go and ssearch for the unfortunate guides: I offered him my hand, and partly. sunk in the snow, still moveable, we advanced in spite of the guides, towards the crevice of unknown depth filled -with snow, and to the place in which they must have fallen. ‘There we descended into this gulph, and I sounded the snow every where with a stick without feeling any resistance. Sup- posing it possible that the men might have fallen into’ some ‘cavity, Or upon some projection in the crevice; and as the air, -on account of its rarity, does not convey sound well, I thrust the longest stick quite to the endin the snow; and lying down upon it, l applied my teeth to the stick, and calling the men by. their names, | listened with great attention to hear any noise; but ‘all was in vain. The guides came upon us, and forced us, so to express it, to come out of the crevice. They declared our search useless ; they even refused the money that we offered them if they would wait ; they laid hold of MM. Dornford and Henderson; sand while I was still sounding the snow (which had passed the -crevice fora great space), they proceeded immediately with them to some distance; so that I was under the necessity of descend- ing with only Coutet, who had not even a stick; but absorbed in the horror of the event, I was become insensible to danger, and | crossed all the crevices without thinking of them. | did not rejoin my: two companions till I arrived at the Grand Mulet, from whence we set off for the Glacier des Bossons,* and at -half-past eight in the evening, we returned to the Hotel de PUnion at Chamouny, without experiencing any great degree of fatigue. I was the more astonished at this, because, for an hour after the accident, I made great efforts in an elevated situa- tion where the least exertion exhausts the strength. “T shall here add a few words explanatory of our unfortunate accident. it appeared that the upper stratum of the snow on the acclivity lay upon another stratum, which was very slippery on 2 In crossing the Glacier des Bossons, we. found a young chamois upon an isle of ice, surrounded with enormous. crevices, it had probably died from inanition. One of _ the high seracs, under the shade of which we had reposed in our ascent, had fallen in, the interval, and had covered the spot on which we had stopped with its fragments, . / AQ . Dr. Hamel’s Ascent of Mont Blanc. | —PJan. the surface ; and as our track cut the first stratum across, the part which »was above us began to slip upon the other, forming wwhat is called in the l’Oberland de Berne, suogg?schnee, sor rutschlavine. In that part where the first of our filewalked, the sacclivity was much steeper than near me where I had measured it va little before the accident ; there it inclined atian angle of 28°. »Further on, the mass of snow was also thicker,:especially high -up ; for the wind usually drifts there the loose snow blown from ethe summit. For these reasons, the slipping necessarily began at this place, and the snow descended directly towards the 'erevice ;. while about me it took an oblique direction forward. -It was on this account that the three first of the file* felliso ‘deep into the crevice, and were covered with snow, so that:we ‘were unable to discover them, while the fifth and sixth,+ who shad also fallen in, were able to disengage themselves. Coutet secame up with his face of a blue:appearance, and with symptoms .of suffocation. Mathieu Balmat, who was a very strong man, rand one of our principal guides, walked fourth, was the only one -who could withstand the slipping of the snow. Thrown down and eafterwards carried to some distance, he had the presence of mind .to thrust:his large stick down, like an anchor, into the hardened esnow. The two other guides } were, like us three travellers, buried in the snow, and forced towards the crevice, without, however, fall- dng intoit. The guides reckoned the surface of the snow which ‘moved tobe nearly 100fathoms broad, and 250 high in an oblique direction. From the firmness of the snow which had slipped, it _ owasevident that ithad not lately fallen. The guides most accus- “tomed to the snow did not suspect any danger. At the moment the accident occurred, the brother of one of our principal guides walked first, and the second was a man who had been this gourney 12 times. In coming from the side of St. Gervais, pass- ang by the Aiguilles and the Dome du Gouté, it is necessary to i the route to Chamouny, in order to reach the ‘acclivity, which deceived us when we imagined all dangers were past. “‘ Whether we ascend one side or the other, eveniafter ee escaped as I| did, the formidable rocks of the Aiguilles‘du Gouté, sand ‘passed the gulphs of the Glacier des Bossons, we incur the «danger near the summit of being swallowed up by the yielding of the snow which at first appears to be firm, but ‘suddenly gives ‘way—a species of danger against which it is difficult to findva preservative.” * They were Pierre Balmat, brother of Mathieu, and eldest son of P. Balmat, one “ofthe ancient guides of M. de Saussure ; Pierre Carrier, a smith by trade, who had ebeen 1) times:upon Mont Blanc; and Auguste Terraz. This/last and P. Balmat had -never been on Mont Blanc, and ‘were the two guides who refused to remain. atthe “Grand Mulet. These three carried the provisions, the instruments, the pigeon, and a on th odhet nar ne incipal guides (his father was also with M. de “Saussure), and Julien evceaians ore ne being poisoned by oil of vitriol. _ pf, David Coutet, the trother:of Joseph ‘Marie; our principal ‘guide, end ‘David -1821,] New Clinometer.—Red. Snow. £48. -ArTIcLE VI, Description of anew Clinometer. By S. P. Pratt.” \ aa (With a Plate.) e: (To the. Editor of the Annals of Philosophy.) | 5 TR, Tottenham, Dec. 1820. _ dT senp you a drawing (PI. II.) of a simple instrument which T have had some time in use for determining the dip of strata: it. consists of a brass ruler, of 12 inches by 3 of an inch in breadth, ‘closing upon an hinge, and covering, when closed, an arch drawn from the centre of the hinge, and divided into 90 degrees on thé same side; near one extremity of the ruler a small spirit level is inserted truly horizontal, with its edge—the applica- _ tion is obvious. The ruler being closed, with the level upper- most, is placed parallel to, or upon any projecting edge of, the strata to be examined, and then gradually opened until the level becomes horizontal; the bisection of the arch near the hinge of the ruler will give the angle formed by its two legs, and consequently the inclination of the strata with the horizon. I am, Sir, yours, 8. P. Pratt. ° \" “h Note.—The simplicity of this instrument appears strongly to recommend it, It\is made and. kept for sale by Mr. Bate, Poultry. Ed. Axticix VII. On Red Snow. By Dr. Henderson. (To the Editor of the Annals of Philosophy.) _. DEAR. SIR, - . Curzon-street, Dec. 9; 1820. -. In the several accounts which were given of the red snow found in Baffin’s Bay, I do not recollect that any, one -has adverted to the fact of this:phenomenon being familiar to the ancients. While I was lately turning over the pages of the ‘indefatigable Pliny; fora very different object, [stumbled upon “@/passage' (lib. xi. ¢..35):where he mentions that snow turns red iby age —“ipsa nix vetustate rubescit.” Nor is the cause: thus ‘assigned for the colour by any means inconsistent with the best -analyses of the red snow as brought to this country in a liquid ‘form; forit is evident that if this variation of the colour of the ‘snow on particular spots be the result of the formation of a lichen “or byssus on its surface, it-can only be on the old snow ‘that “such vegetation willioccur. ’ I remain, dear Sir, : So. Ss Your most ‘obedient servant, std >t. "M, Henperson, 44 New Method of drawing a Tangent to the Circle. [Sam ArtTicLeE VIII. A new Method of drawing a Tangent to the Circle. By Mr. William Ritchie, AM. of the Academy, Perth. (To the Editor of the Annals of Philosophy.) SIR, | I wave taken the liberty of sending you a new method of “drawing a tangent to the circle which appears to me simpler ‘than any of those already known, and which I hope will find a place in your Annals of Philosophy. For the advantage of the young geometer, I have accompanied it with the analysis, or the mode, by which it was discovered. I am, Sir, Your obedient servant, WiiiiaM RITcHuIE. te Analysis. Let B F D be the given circle, C its centre, and A the point, from which the tangent is to be drawn; and let AF be the tangentrequired. Join CF, and produce it till F E be equal to F C, join A E. Now since the angle A FE is equal to A FC, each of them being a right angle, and since F E is equal to FC, and A F common to the two tri- angles A F Cand A F £, these tri- angles are equal, and consequently A E is equal to A C, which is given. Again C E is given, being equal to the diameter of the circle ; therefore the point E is given, the line C E and F ‘its intersection with the circumference, which is the point ‘required. | n Composition. From A with the radius A C describe an arc, and from C with a radius equal to the diameter of the circle describe another, antersecting the former in E; join C E and F its intersection with the circumference of the circle will be the point of contact required. , 3 or C E being equal to the diameter of the circle, and C F the radius, F E is equal to F C, A C is equal to A E, and AF common to the two triangles A F C and A FE; therefore, these triangles are equal to each other, and poem orstig the angle A F Eis equal to the angle A FC; that is, AFC is a nght angle. Hence A F is a tangent to the circle. 1821.] Dry Rot.—Fall of Rain 45. ArTICLE IX. On the Dry Rot. By Mr. W. M. Dinsdale. (To the Editor of the Annals of Philosophy.) SIR, : Nov. 25, 1820. Permit me to ask some of your more scientific correspond- énts, ‘‘ In what light they view the following analogous circum. stances AM with the subject of dry rot in timber, and whether they do not in some measure consider them to throw a ray of elucidation on that important head ?” | 1. In recent vegetable juices, I think, we have grounds for. believing in the existence of acetous acid as well as its consti-+ tuents. : 2. Casks used for manufacturing vinegar soon decay if they are not thoroughly cleansed from the mother or sediment formed. in. the operation. 3. Baked wood is less subject to dry rot than that which is unbaked. 4. Tar, both of the Stockholm kind, and that which had been. made at the gunpowder charcoal works, has been found to rot the palings at Woolwich, &c. in a space of time seldom exceed- ing three years, and frequently considerably less, which rot was decidedly attended by all the appearances of dry rot; while it is equally certain the rot alluded to has never followed the use of either kind, when freed from its pyroacetous acid. I am, Sir, ! Your obliged and obedient servant, | W. M. Dinspate. *,* We are in some doubt as to the absolute correctness. of our correspondent’s views, but as the subject of the dry rot is one of great importance, we shall be happy to insert any hints which may tend to elucidate its causes, or remedy its effects.—En. , ARTICLE X. On the Fall of Rain. » (To thejEditor of the Annals of Philosophy.) SIR, Dec. 9, 1820. THe letter inserted in the last volume of your Annals of Phi~ losophy, p. 421, recalled my attention to M. Flauguerges’s paper, and more particularly to the remarks which he makes (Annals, vol. xiv. p. 113, 114,) on the relative quantities of rain which are 46° Dr. Bostock:on Whale Oil. [Jane received by gauges at different heights from the surface of the earth. [I do not mean to enter into the controversy with respect to the direction of the drops: this I shall leave to Mr. Meikle and his antagonists, but there is another part of the question which seems to have been overlooked, and to which, therefore, I could wish to call the attention of your readers; L am persuaded by private observations, as well as by those which have been made public, that the fact is certainly true of more rain falling near the earth’s surface than at’ some height above it. This seems to be a paradox, and many-have, there-' fore, endeavoured to explain it away, but still it seems to me to be a necessary consequence of the very constitution ofthe atmo- sphere. Clouds collect before rain falls, but this is not in con-* sequence of their being the only source of moisture, but of the, upper strata of the air being first affected by those causes’ which produce the rain. The quantity of rain is made up of a neral discharge of water from the air between the earth and e region of the clouds. Hence the effects must accumulate’ as we approach to. the earth, and the results which have been’ dbserved must not be wholly attributed to the wind, or to any accidental circumstances which may affect the instruments’ which are used for the admeasurement. N: ! ArTICLE XI. Some Observations on Whale Oil. By J. Bostock, MD. FRS. LS. and HS. MRI. Mem. of the Med., Geol., and Astron. Soc. &c. &c. Great Coram-street, Dec. 21, 1820. Tue object of this communication is to give an account of some experiments in which I was concerned that were made in. order to ascertain the changes that are produced in oil by expos ing it for a length of time to an elevated temperature.* ith- out going into a minute detail of the individual experiments, I shall state some of the most important of the results, and shall afterwards offer a few observations upon the nature of the pro- cess and upon the mode by which the change is effected. The quantity of oil operated upon was generally from 25 to 30 gal- lons; the fluid was contained in a boiler three feet long, one foot six inches wide, one foot three inches deep; fire-place 14 inches long, three inches wide; the bars three inches from the bottom * The. experiments were performed at the manufactory of Messrs. Taylors and, Martineau, in the presence of several scientific gentlemen: among others, of Mr. Chil. dren, Mr. Aikin, Mr. Daniell, Mr. Richard Phillips, and Mr. Faraday. - 1821.] Dr. Bostock on Whale Oil. 47 of the boiler. The’ oil occupied about two-thirds of the vessel; it had a concave bottom, and was closed air-tight, except that a tube of half an inch diameter was inserted into its upper-part. ‘Flie temperature employed was 360°, and the oil was carefully: kept at that degree of heat during 12 hours each day. In the different trials the process was continued for 22, 25, 26, 38, and 55 days respectively, until, in one instance, it: was extended to: 68 days. ‘The substance employed was the whale oil of com~ merce, in the state of purity in which the article is usually exhi~ bited for sale. , | - Whenthe oil was examined, afterhaving been kept at the above temperature for the periods above stated, its physical properties! were considerably altered, its colour was nearly black, its con- sistence thick and tenacious, and its odour empyreumatic. ‘When heat was applied to it in this state, after it had been cooled. down to the temperature of the atmosphere, the first effect was-to render it more fluid ; and at higher degrees of heat its consistence seemed to be considerably less than that of recent oil. While the’ oil was ‘in the boiler, and at the temperature of 360°, an internal motion took place among its parts, that seemed to arise from some portion of it being converted to the aeriform state, and suddenly condensed: this was indicated by a peculiar sound emitted from the vessel analogous to the simmering of water before it is raised to’the proper boiling point. It was observed that the simmering, if we may so term it, diminished as the oil exceeded the temperature of 400°; and after it had acquired the heat of abcut 45U° was no longer heard. But the most material alteration in the oil was the property which it had acquired of emitting vapour when it was subjected to temperatures which would have had no effect of this kind upon recent oil. Both the quantity of the vapour, its chemical composition, the mode of its generation, and the degree of the thermometer at which it first appeared, were very different in the different experiments ; and there does not appear to be suffi- cient data for forming a correct opinion upon any one of these points. One of the circumstances which seemed the most favourable for its production was: the rapidity with which the fluid passed through a certain range of temperature. Oil, for example, which was steadily kept at 360°, although it had acquired the dark colour, seemed to produce little aeriform fluid of any kind, with perhaps the exception of a portion of carbonic acid; and there is some reason to suppose that it might bear even a higher temperature, provided the heat be cautiously applied. But if, on the contrary, the heat be more rapidly raised, a copious discharge of an aeriform fluid takes place, which essentially consists of inflammable and aqueous vapour mixed in variable proportions: The total amount of vapour emitted, the proportion of the aqueous to the inflammable part, and the che- 48 Dr, Bostock on Whale Oil. [JANS mical nature of this latter, have not. been correctly ascertained,, nor is it known whether any thing is procured which is entitled: to the technical appellation of gas. It may, however, be stated: generally, that the quantity of vapour is large, that the propor- tion of the ingredients vary in different parts of the same experi- ment, and that the aqueous is more condensable than. the inflammable part. This appeared by ‘bringing a cold body in contact with the vapour, and the condensation frequently was observed to take place merely by the ordinary temperature of the atmosphere: in this case the inflammable part was left in a highly combustible state. The difficulty with which this inflam- mable vapour is condensed was strikingly illustrated by one experinient, in which the oil vapour was passed through a worm tube of 23 feet in length: by this means the aqueous part was. entirely removed, and the residue burned with a continuous bright flame. The water collected in this case was strongly, acidulous, in consequence, as it appeared, of the copious gene~ ration of acetic acid. : In most of the experiments the emission of inflammable vapour was scarcely perceptible below a temperature of 400° “ but in one instance, where the oil, after having been in the boiler for 55 days, was suffered to cool to the temperature of the atmosphere, and then heated by a brisk fire, a quantity of vapour. was generated below 210° (the degree at which the graduation of the thermometer commenced), which, by the application of a lighted taper, exploded with some violence. Speaking from. general observation it would seem that when, the temperature of the oil is raised to about 420° or 430°, the proportion of the inflammable to the aqueous vapour is more considerable. If the _ temperature be further raised to about 480°, the proportion of the aqueous vapour is increased ; while at a still higher tempera- ture, above 500°, the inflammable vapour again predominates.. With respect to the phenomena which the mixed vapour exhibits during combustion, it may be remarked that its inflammation is not attended with detonation ; when the aqueous part. prevails, the flame is quickly extinguished; but that in proportion as it is. freed from the aqueous vapour, it burns with a considerably dense: and brilliant flame. : ids besesa | _ Another effect which appeared to result from the long conti-. nued application of heat was, that the oil had its boiling, point. lowered, or, to speak more correctly, that below the température. which is Seasle regarded as the boiling point. of ;recent oil, the heated oil, was rapidly converted into an. inflammable, vapour, but of a different kind from that,procured at lower tem-. eratures ; the vapour procured from, the,boiling oil, containing. ess water, and having a highly offensive and most penetrating odour; whereas the former vapour had comparatively; little smell, and that not peculiarly disagreeable.. The change to 1821.) Dr. Bostock on Whale Oil. 49 which I now refer, generally took place at about 580°:* it appeared to consist in the vaporization of the residual fluid in” the boiler; but it was not strictly entitled to the appellation of » boiling, because it does not appear that by condensing the vapour, a fluid could be reproduced similar to that from which it was procured, The above observations are to be regarded as matters of fact, independent of hypothesis; but it is impossible to yigeiar dente the phenomena without speculating upon the changes which the oil may be supposed to have undergone by the long continued action of heat upon it. We may conceive that during this ope- ration the elements of the oil act upon each other, and that the fluid is converted into an heterogeneous compound ; that the first new product is a substance spingel} a larger proportion of hydrogen, and constituting a highly volatile oil, capable of being brought to the aeriform state by a comparatively low temperature. The next accession of heat seems to be attended with the production of water, which is emitted along with the vapour of the volatile oil; while at length, by a further increase of temperature, the substance remaining in the boiler, now deprived of a considerable proportion of its oxygen and hydro- gen, gives rise to a highly inflammable pungent vapour, compa- ratively free from water, but accompanied by a considerable proportion of acid. Although the experiments seem to iat that at least a small quantity of the volatile oilis capable of being generated at the temperature of 360°, yet it is probable that the chief effect of this temperature is to produce a change in the oil, which may dispose it to the production of the volatile mat- ter at a somewhat greater heat, the mode in which the heat is applied being, to a certain extent, more important than the actual degree to which it is carried. It is unnecessary to remark that the facts which have been observed, although, as I conceive, new and important, are to be considered as constituting only the first step of an investigation, which will probably lead to many curious results. In what degree the phenomena depend upon any thing peculiar in the nature of whale oil in its ordinary state of purity, or upon an heterogeneous substance contained in it, is the first point that it will be desirable to ascertain. In the next place it will be important to watch the gradual progression by which the oil has its physical and chemical properties so much changed, and to discover at what degree, or after what period of time, the maxi- * In one of our experiments a species of ebullition occurred at a much lower tem- perature, about 460°, the fluid being violently projected in considerable jets from the vent pipe to the height of nine feet or more, when the surface of the oil was about five inches below the cover of the boiler, and the orifice of the vent pipe screwed into it. We were, however, induced to regard this as not the result of the rapid volatilization of the entire fluid, but as. depending upon the more volatile part of it being suddenly converted into vapour, which, intimately mixing with the viscid mass, for 7 & portion of it out of the tube. New Series, vou, t. D 50 Dr. Forchhammer on pure Salts of Manganese, [Jan. mum of effect takes place, or whether indeed there be any term of this kind, It will be next desirable to learn what is the lowest temperature at which the volatile oil and the water are respect- ively generated, and to examine at different temperatures, and at different periods of time, the proportion which these substances bear to each other. It will likewise become a very curious subject of investigation to learn with more accuracy the nature and properties of the inflammable vapour, whether it consist merely of the volatile oil in a vaporized state, or of this mixed with some permanent gas ; if so, whether the gas resemble any species of carburetted hydrogen with which we were previously acquainted. Lastly, we must investigate the nature of the vola- tile oil, when obtained in a separate state by distillation, and also that of the acid generated in the latter part of the opera- tion, whether it be actually the acetic acid, or in what respect it differs from this acid as obtained by the ordinary processes. ARTICLE XII. On the Preparation of pure Salts of ws econ and on the Composition of its Oxides. By G. Forchhammer, Ph. D. - THE principal ore of manganese wrought for the preparation of chlorine is the common grey ore of this metal, or the peroxide. I have tried several of the ores which occur in Germany in veins and beds in a porphyry belonging to the first secondary sandstone, and found them all containing some copper, in very small quantity, excepting of course the complete crystals of it which are generally free from this admixture. It appears that the Devonshire ore is found in the same geognostic position as those above-mentioned; and I found this likewise containing some traces of copper, which, though the combination does not bear the character of a chemical compound, is a striking instance of the similarity in the formation of the same mineral in far dis- tant countries. Besides copper, iron always is present, and a small quantity of barytes, and even of lead, occur ver often. Iron, however, is an admixture, the separation of whic has generally been the most attended to; and many chemists have attempted to remove it by simple processes. There is no doubt that the benzoate and succinate of any alkali will throw down all the deutoxide of iron ; but if there is protoxide, it may escape to a certain degree, and then these salts are so expensive that, for preparing a quantity of the pure oxide of manganese, it would be desirable to find another process. The method I made use of is the following: I prepared in the common way sulphate of manganese by hecdet equal parts of peroxide of " manganese with sulphuric acid, only taking care to keep it in the fire until vapour of sulphuric acid ceased to appear; ¥ 1821.} and on the Composition of ats Oxides, 51 by these means. the. bisulphate..of protoxide and. the sul- shuts of deutoxide, are decomposed, and converted into sulphate of protoxide.. The solution, which of course could contain neither barytes nor lead, whatever quantity of them there might be in the ore, contains only the sulphates of manganese, iron, and copper. In order to remove the two latter metals, I poured successively into the solution of the manganese a solution of hydrosulphuret of ammonia, which first precipitates the copper of a black colour, then the iron likewise black, and at last the. manganese of a white colour. When the colour of the precipi- tate turns grey, I heat the liquor to the boiling point, and then allow it to remain undisturbed for the purpose of trymg it with tests. The prussiate of potash is sufficient for that purpose, which precipitates the salts of pure manganese of a white colour; the slightest trace of iron is. directly shown by a blue colour, and capes by. red. The crystals of sulphate of manganese which I made use of for the analysis were made in a different way to avoid.the presence of any alkali. Through the impure sulphuric solution of manga- nese, I passed sulphuretted hydrogen to remove the copper, and then concentrated it by evaporation until it became a very strong solution, which, however, did not crystallize when cold. Spirit of wine containing 80 to 90 per cent. of alcohol divides the solution into two parts, the lower of which soon deposits crys- tals of sulphate of manganese, often entirely free from iron, but sometimes they contain a very slight portion of it. From the pure sulphate of manganese above-mentioned, I obtained by carbonate of potash the carbonate of manganese, which yielded me all the different oxides. I tried often to prepare the pure metal from one of these oxides, but I never could succeed. I exposed it, with charcoal, to the heat of a furnace, in the china manufactory in Copen- hagen, where iron melts very easily ; but though the oxide was reduced, and the powder in the crucible dissolved in acids, with the evolution of much hydrogen, it was not melted; and whe- ther it was metal, or an oxide containing less oxygen than the protoxide, I was not able to ascertain. In another experiment, when I exposed it to the heat of a large anchor-forge, | obtained small grains. On the Protoxide. I found it rather difficult to obtain a protoxide completely free- from all deutoxide. ‘The usual way, by heating carbonate of manganese in a retort full of carbonic acid, did not appear to me very accurate, as | never was able to obtain a carbonate.of protoxide of manganese completely free from all deutoxide. All the solutions of protoxide, if they have been exposed to.the air, dz 3 2 52 Dr. Forchhammer on pure Salts of Manganese, [JAn- contain a small quantity of deutoxide which occasions their red- dish colour, and the carbonate being obtained from them of © coutse contains the same. That the red colour of the solutions f manganese depends upon the presence of deutoxide, I had oi opportunity of observing in the following way : “Tn my paper on the Acids of Manganese, I have mentioned the anode in which I decomposed the brown compound of lead, manganese, and oxygen, by bisulphate of potash; and I made use of the same method for ascertaining the quantity of oxygen combined with protoxide in the -deutoxide and peroxide. I und that. when the greater part of the oxygen was expelled by e combined action of heat and the bisu abies of potash, the powder was entirely dissolved, and formed a beautiful transparent amethystine coloured solution, which still yielded oxygen, and became of a pink colour. The expulsion of oxygen did not cease until the melted salt in the retort was entirely colourless, and it remained so when cold. A solution of it in water was colourless, but, when exposed to the air, it soon acquired the slight pink colour, which is characteristic of all the salts of man- ore This experiment proves obviously that the colour epends upon the surplus of oxygen combined with the protoxide, or that all these pink-coloured solutions and salts contain both protoxide and deutoxide ; the latter, however, only in very small quantity. ‘ ’ The way I proceeded in order to obtain pure protoxide was this: 1 filled a glass tube, open at both ends, with deutoxide, oe heated it over a lamp while I passed hydrogen gas through it. The brown powder soon changed to a light yellow, which colour, while the powder was cooling, became white, and the cold oxide was of a beautiful h hiboedh: This colour, however, changed in the air; for while I was taking the open tube to a pair of scales in another room, it evidently attracted oxygen, and its colour changed into greyish-green ; and when converted by combustion agaiz into deol, it gained five per cent. “There is not any reason to induce us to suppose that in this case the protoxide had been reduced to ubomide by the action of hydrogen, for the heat was very gentle, and from the power with which the metal decomposes. water even in the common temperature of the atmosphere, we scarcely can expect that in so slight a heat, hydrogen should deprive the Seotoadite of a part of its oxygen. "To ascertain the quantity of oxygen in the protoxide, I ana- lyzed the sulphate and carbonate. | T heated a certain opti of sulphate of manganese to red- ness, then dissolved it, and’precipitated the sulphuric acid by nitrate of barytes. Five grammes of perfectly dry sulphate of manganese gave me 7913 grammes of sulphate of barytes, 7 1821.) | and on the Composition of its Oxides. 53 which are equivalent to 2°7181 grammes of sulphuric acid, allow- ing that 100 parts sulphate of barytes contain 34°35 parts of si huric acid. | ot Oni hundred parts of sulphate of manganese consist, there- fore, of di Sulphuric acid. ........ soba! saith . 54:378 Protoxide of manganese. ......0«.. 45°622 | 100-000 ) ike hundred parts of protoxide of matiganese combine with 119-192 parts of sulphuric acid, which contain 71-5155 parts of oxygen, and thus we find the protoxide of manganése consist- ing of | . CFRVEONS cpap cr se cee Beak Wei be ~ 23°8385 WRANvAREHE oe Oe Se § PE FOL OTS 100-0000 Or 100 parts of manganese combine with 31-29 parts of oxygen to form the protoxide. af In another experiment, where I had.reason to suspect that the heated sulphate of manganese had again attracted some water, I obtained 7°731 grammes sulphate of barytes from five grammes of sulphate of manganese. After having precipitated all the excess of barytes in the solution, 1 threw down the manganese by carbonate of potash, and having converted it into deutoxide by exposing it to a red heat in an open vessel, the quantity suhcioad was 2°480 grms. I shall be able hereafter to prove, that the deutoxide consists of 92°4342 parts of ntotdside and 7:5658 parts of oxygen: 2°480 grms. of deutoxide consist, there- fore, of OXv Re. v0 p's Go's tie oe Wh ainieraias wh 0:18764 PROLOKIRS asia p fe Pes PAL ew owe ead 2h 2°29236 - The sulphate of barytes obtained indicates 2°6555 grms. sul- phuric acid, which combine with 2-29236 parts of sulphuric acid. rit} One hundred parts of protoxide of manganese, according to this experiment, would combine with 115:90 of sulphuric acid ; and they, therefore, would consist of it | RVC 4: gn aidiea's see 6'N Ore re 23°18 Manganese ......... BS aitidie Spd a oe 76°82 Or 100 parts of manganese combihe with 30:18 parts of oxygen to form the protoxide. ) : ? I several times heated the deutoxide with sulphuric acid; and by the quantity of sulphate of manganese thus obtained, I endeavoured to find the quantity of sulphuric acid, but the vapours of this acid always carried off some sulphate of manganese, which was 54 = _> JUST PUBLISHED, A System of Chemistry, in Four Volumes, 8vo. By Thomas Thomson, MD. ~ Regits Professor of Chemistry in the University of Glasgow, &c. &c. Sixth _ Edition, revised and corrected throughout. Price 3/. boards. A Dissertation on the Treatment of Morbid Local Affections of the Nerves. By Joseph Swan. 8vo, 10s. 6d. An Essay on the Diagnosis betweeu Erysipelas, Phlegmon, and . By George Hume Weatherhead, MD. 8vo. 4s. \ ot ~ 821.) New Patents. 75 - The Pharmacopeeia of the Royal College of Physicians of London, 1809, lite- rally traoslated by George Fred. Collier, Surgeon. 8vo. 10s. 6d. ..Elements of Chemistry, with its Application to explain the Phenomena of Nature, &c. By James Millar, MD. 8vo. 12s. 7 Sound Mind, or Contributions to the Natural History and Physiology of the Human Intellect. By J. Haslam. 8vo. 7s. | Practical Treatise on the Diseases of the Eye. By John Vetch, MD. 8vo 10s. 6d. A Treatise on Mildew, and the Cultivation of Wheat, including many Agri- cultural Hints. By Francis Blaikie. 1s. 6d. ~The Botanical Cultivator, or Instructions for the Management of Plants cul- ~ tivated in the Hot-Houses of Great Britain.. By Robert Sweet, FLS. 8vo.. 10s. 6d. Grisenthwaite’s New Theory of Agriculture, in which the Nature of Soils,, &c. is explained. By J.C. Curwen, Esq.MP. 8vo. 5s. View of the Intellectual Powers of Man, with Observations on their Culti-- vation, adapted to the present State of this Country. 8vo. 5s. 7 ARTICLE XVII. NEW PATENTS. William Acraman, Jun. and Daniel Wade Acraman, of Bristol, for improve-- ments in the processes of forming the materials for manufacturing chains and chain-cables. Oct. 16, 1820. Joseph Main, Esq. of Bagnio-court, Newgate-street, London, for improve- ments on wheeled-carriages. Oct. 20. James Richard Gilmour, of King-street, Southwark, and John Bold, of Mill-- pond Bridge, Surrey, for improvements on printing-presses. Oct. 20. Thomas Prest, of Chigwell, Essex, for a new and additional movement to a watch to enable it to be wound up by the pendant knob, without any detached: key or winder. Oct. 20. John Bickinshaw, of Bedlington Iron Works, in the county of Durham, for improvements in manufacturing and construction ofa wrought or malleable iron rail road or way. Oct.23. William Taylor, of Wednesbury, Staffordshire, furnace-worker, for an im-=- proved furnace for smelting iron and other ores. Oct. 23. Thompson Pearson, of South Shields, foranimprovementonrudders. Nov. 1. Henry Lewis Lobeck, of Tower-street, London, for an improvement in the- process of making yeast. (Communicated by a foreigner tohim.) Nov. 1. Samuel Wellman Wright, of Upper Kensington, Surrey, for a combination in. machinery for making bricks and tiles. Nov. 1. Peter Hawker, of Long Parish House, near Andover, for a machine, instru ment, or apparatus, to assist in the proper performance on the piano-forte, or other keyed instruments. Nov. 1. Thomas Bonsor Crompton, of Farmworth, Lancaster, for an improvement in drying aud finishing paper, by means hitherto unused for that purpose. Nov. 1. William Swift Torey, of Lincoln, for certain improvements in drills, to be |, affixed to ploughs. Nov.1, _ | _,.. Sohn Winter, Esq. of Acton, Middlesex, for improvements on chimney-caps, and in the application thereof. Nov. 7. — _ Wiltiam Carter, of St. Agnes Circus, Old-street road, printer, for improve- ‘“oraments in steam-engines. Nov. 11. — ; ; ‘Thomas Dyson, of Abbey Dale, Sheffield, for an improvement, or improves . Mepts of plane irons and turning chisels. Nov. 11. 76 = =—— Col. Beaufoy’s Astronomical, Magnetical, — \fJan. | ArticLe XVIII. Astronomical, sa Si and Meteorol y Col. Beaufoy, F.R.S. Bushey Heath, near Stanmore. - Latitude 51° 37’ 44-3” North. Longitude West in time 1’ 20°93”. Astronomical Observations. . -\Noy. 1. Emersion » of Jupiter’s satellite. Ree meee en ew eee 7 42 ovical Observations. \ first § 7» 40’ 51 Mean’Time at Bushey. 12. Mean Time at Greenwich. Magnetical Observations, 1820. — Variation: West. Morning Observ. — | Noon Observ. Evening Observ. Month. Hour. Variation. Hour. Variation. Hour. Variation. Noy. 1] 8h 35’| 24° 31’ 46” 1h 95°] e40 38’ 10” 2} 8 40| 24 31 36] 1 30/24 37 58) 3 31 8 40| 24 $212) 1. 35|24.37 48 2 4} 8 35| 24 32 18] 1°20} 24 38 09) 5| 8 45|24 81 37] 1 20|24 87 16 2 6; 8 40) 24 32/21] 1 20 //24-38 00] 8 TY ime, mre fi mee mee Des 95: 8A! 40 69 | 8} 8 40] 24 32 32] 1 30/24 38°08) 9 | 9} S 40} 24 32 27]°1 20} 24 38 00} 3 10} 8 40/24 32 08} 1 35] 24-87 8) & » HH] 8 635] 24°82 10} 1.25 |-24°31 35) 8 12} 8 40] 24 32 50] 1.15 |24 37028) 2° AS1 Sii: AO: 94 ASW ARB? esis cbiet he nireenl i) BRR 14) 8 35 |24 39 50] 1-95} 24.47 16] 3 15] .8..35 } 24, (87, 52... 1) 20.|,24; 36.54) 9B 16] 8 $5} 24.32.25] 1),.20,|.24 36 56 gd Mm] 8 40 | % St Se PS ee oe Le 18|.8 40] 24,31. 58|..4 26124 87.33] 3 19} 8 45 | 24 31 30] 1 25} 24 37 18} “3 20} 8 40°}-24 °31°50} 1° 25'}24 47 OT 21| & 40| 24 34 57]|_1 25|24 47 45 < 22/8 35) 24 32°06} 1 55/2436 39) 8 23} 8 35}24 31 .38)} 92 2b) 2der37 eb | oo 8» 244 8 40 | 24.682 49 } 01 625 | 24°37 119} 8 D5] B 45 f 24 133-0102 | Bow®O-fp2413% 46} 55 26] 8 35 |:24 33.00} 1..20,},24..37 02| .3 27| 8 Ad | 24,:33..39.| 1: 85 | 24, 37.29]. 0g 281 8 35/24 32 44) 1 15 | 24. 36.46 oe 29| 8 40|24 33 22| 1 1o}24 36 58| | | ae a m ateet ele ip tieiny Pend papeie pete ro) Mean for the < 39 | 24 32 23) 1 25'| 24 87 38 ‘Month. é Gi. In taking the mean of the observations; those on the 14th and those of the morning of the 15th are. rejected, being so great; and it.is remarkable that this.excess continued only on the falling of snow. On the weather clearing up‘ prior:to: observing - “the noon variation of the 15th, it had decreased. ‘The noon observation of the 20th is likewise rejected ; this increase was attended with drizzling rain. and Meteorologicat- Observations. Meteorological Observations: Barom. ei. Hyg. Wind. | Velocity. | Weather. Inches, Feet. | £8893 | 43° | 76°) WNW Rain | 28-977 | 43°] 73 NW by W Showery “| e9-274 | 33 | 74-| wsw veiy fine! ¢ .| 29°283 | 45 65 | WbyS Very fine}: "T} 29-400 | 37° 72°) NW ~- -|Cléar | 29-400 | 45 | 60 Ww Very fine), ‘|| 99-392 | 37 | 72 | ENE Cloudy ‘ | 29:399 | 45 | 68 | ENE Fine ‘| 29-455 | 36 | 63-| ssw Fine |S .| 29-400 | 38 71 SE by S Cloudy ..| 29-267 | 48 | 87 | Wsw | | Misty ‘ .| 29°294 | 50 73 WSW Cloudy | 29-284 | — | 90.| SEbyS Fog ‘ .| 29°295 | 54°] 70 SSW Cloudy > fs ronan tas Oo tien i | 29375 | 52 | 84 | Ebys Fog ‘ | 29:369 | 54 | 177 ENE | Rain | 29-469 | “45° | 74 ENE | Fine ‘ .| 29-467 | 46°| 64 | ENE Cloudy » | 29543 | 42 + 74°] NE | Sm. rain ‘ .| 29°547 | 45°] 60 NE Cloudy. | 29-678 | > at 74 N by E Cloudy ; | 29-718 | 47 | 62 | NE | Fine | 29°648 | 38 69 W by N Fine ; 29°500 | 40 68 W byS Sm. rain 29:094'| 36°} 77 |) NNBi |» | |Smerain: ¢ | 297048. | — | 78 |. NNE Sleet . | 29°300 |°34° 195°) NNE | Snow ‘ 29-294 | 35 | 70 NE .. Sni. show.} 29°433 | 32 71 NNE Very fine ‘ | 29-439 | 40 | 63 NE Fine . -| 29°464 33 75 N Clear .| 29-400 | 39 | 61 NNE Cloudy 429-163 | 32 | 73 SE Snow | 29:103 | — | 18 SSE Rain © 29°339 | 36 17 | NEbyE Very fine ‘ 29°379 | 42 68 | NbyW Very fine $3 wl ®. > © a wm Gr 69 oo @ i) =] coe -— a oo 65 he ips hs =" en BF > oo 3 < eqs 78 Col. Beaufoy’s Meteorological Observations, [Jan | f J g Month. | Time. | Barom. | Ther. | Hyg. Wind, | Velocity. Weather. ‘Six’s. Nov. Inches. Feet. ’ Morn eee 29°482 37° so0° SE Misty 34 xf 19¢ |Noon....} 29°450 44 72 SSW Misty 44 Even ....| .— — — _ —_ ¢ 40 Morn....| 29500 | 43 | 84 | Sby W Sm, rain |$ “8 “902 |Noon....| 25°464 | 47 | 176 SSW |Sm, rain |. 47 Even eeee — = Bee > —— ‘ AG Morn,...| 29-408 | 47 | 80 | Sby W Cloudy $ 24 Noon....| 29°400 50 67 Ss , Fine 504 Even....) — — = —_ a 4b Morn....| 29°308 | 45 75 | SE byS Rain ‘ 22< |Noon....| 29°263 45 76 ESE Fog, rain ATE Even....) — on sag —_ a ae Morn....| 29°085 | 42 | 84 | EbyS | | Fog & 234 \Noon....| 29°982 | 46 83 | Nby W Rain AG Even eee a +o ie eben — 36 Morn.,..| 29208 | 38 79 SSE Cloudy any 24% |Noon...| 26217 | 43 |.77 | ESE Fog, rain} 433" Even....| — — » es _— : 4 Morn....| 29090 | 42 | 82 | ESE | Cloudy ha 25< |Noon....| 29083 | 45 15 ) ESE Fine AT Even....) — a — -- 4 Morn...) 29°319 | 44 83 SSE Cloudy 2 26< |Noon....| 29°390 49 10 SSW Fine 50: Even..... — ones °F —_ — 3 Morn,..{ 20-438 | 41.| 78 | & |. Irine. |¢ 408 274 |Noon....| 29°438 | 47 | 64 E Fine ATR ‘ Even eeee ae b+ vad Sey Sue boomer 36 Morn....| 29°603 | 38 | 82 | ENE Cloudy . 284 |Noon....| 29°628 3%}, 78 NE Cloudy 38 ; Even.... — ae reas oe EB ser 36 Morn....| 29°800 37 13 E by. N: |... . Cloudy. ‘ 294 |Noon....| 29°800 38.) 170 } NEV fF Cloudy | 394. Even... — f — — _ _ Morn....} 29773 |. — | 79 | NEby N Cloudy ‘ ” s04 Noon....) — _ _ _— _ 392 Even....) — —_ —_ —_ — Ld Rain, by the pluviameter, between noon the Ist of Nov. and noon the Ist of Dec. 1:223 inch. The quantity that fell upon the roof of my observatory during the same period, 1-305 in. Evaporation, between noon the Ist of Nov. and noon the 1st of Dec. 0°853 in. | | 1821.) .» Mr. Howard’s: Meteorological Table. 79 ARTICLE XIX, METEOROLOGICAL TABLE, RI BaroMETER,| THERMOMETER, Hygr. at 4820. Wind. | Max.; Min.’| Max. | . Min. Evap. | Rain.| 9 a.m. aith Mo. | ‘Noy. IN ‘W/{29°98/29°59|} 56 34 —s 06) -78 2; .W . {30 07/29'98} 48 | 25 } — 72 3). Var. |30°10/30°07| 41 23 — dL 4| N_ {|30°15|30 09} 48 27 — wee - 51S W{30°15/29'G6) 50 30 co 20} 91 6} W_ {29:96/29°91| 52 44, — 87 1@” 71S W({30:05/29°91| 57 50 _ 02} 93 $8} E |30°14|30°05} 56 45 —_—_ i i— 93 9| E |30°20/30°14| 50 41 — 70 10! N_ |30°37/30-20| 46° | 39 — 71 11IN —_E/30°37|30°33| 49 34 — 76 121S_ - W)30°33}29:77|. 43 36 40} 241 66 13} N_ |29°99|29°77| 49 31 — ol. Ok Te 14IN. _E|30°15/29-99} 38 31 — 02) . 62. 15IN —-E}29°99/29 94) 43 29 — |— 76 I6IN W{29:94/29'72) 41 23 — | 84 17|S., E/29°84/29°63} 43 29 — 50}, 78 18} Calm |29°94)29-84; 40 SY — 01} 92 19S ~ Ej29°97|29°94| 47 33 — 90 20/8 E|29°94/29:90| 50 45 _ 90 10 21S E}29:90/29 82} 53 45 —j— 84 22:5 — E}29°82/29°60| 49 | 39 —~ 40} 86 23) Var. |29°71|29'45| 48 30 — 261 90 241$ W/)29 62129°45| 46 | 32 — |_— 91 25} E.. |29°81/29'62}. 48 43 — 16} 94 26)S E|29 92/29°81; 52 38 “— 80 27; E |30°08/29:92} 46 | 33 = 92 i> 98) °E.. -{30:26|30°08} . 39 36 — 83 20IN _—E}30°26}30°23) 41 33 — 70 “30) > N- 130°23/30°17| ° 43 99°74" 55 1°02 FT -130°37/29°45! 57 23 95 | 1°82i 94—62 ‘The observations in each line of the table apply to a period of twenty-four hours, beginning at 9 A.M. on the day indicated in the first column. A dash denotes that _ the result is included in the next following observation. 80° , Mr.’ Héwart?’s Meteorological Journal. “JAN. 1821, REMARKS. Eleventh Month.—\. Rainy: a fine arch of Cirrocumulus stretching from NW to SE, and coloured a bright red by the setting sun. 2. Day very fine: night foggy. 3. A very thick fog in the morning. 4, 5. Hoar-frost: foggy. 6. Fine. 1. Cloudy... 8+ Cloudy, 9, 10, 1. Fines » 12, 13. Rainy. 14. Cloudy: windy: alittle snow“about noon, “15. Cloudy: some hail. 16. White-frost: fine. 17. Somie snow ‘in the morning.| 18. An extremely thick fog, whtich remained most of the morning.» About ten o’clock the coachmen on the road: were unable to see the heads of their horses, which, in many instances; were obliged to be led. 19. Fine. 20. Cloudy: fine. 21. Very fine. 22. Rainy. 23. Morning very rainy: a rainbow about half-past one, p.m. 24, Cloudy. 25. Fine. 26. Fine. 27, 28, 29, 30. Cloudy. RESULTS. Winds: N, 4; NE, 4; E,5; SE,6; SW,4; W,2; NW, 2; Calm,1; Var. 2. Baromieter: Medn height” ae Powtad comnts A. 82...) 0. bbs cde HORII: 29°968 inches. For the lunar period; ending the 26th’:.........4.2., 99°864 For 13 days, ending the Ist (moon north) «.5.......-. 29°189 For 14 days, ending'the 15th (moon south) *)........ 30-076 For 14 days, ending the 29th (moon north) 4. ....4... 29-857 Therthometer: Mean height , Fort the! month. .) 2. isles 04 00 ob be coc cided bbb the Vente oo ct A0GRO For the'lunar period, ending thé 26th’ S.......0s00..6- 466" ' £ ©. For 30 days, the sun\in Seon. ” [Fus. 4, Superoxymuriate of potassa. ....... 4° Flowers of sulphur. ..,......00005 15 Charcoal: powder 16. ss gswies ce eseee LS Nites: sissies 6th d ele delbelise cee wees 2°5 This and Nos. 5and 8 are the third best. 5. Superoxymuriate of potassa. ...... 4-0 Flowers of sulphur. ........00..0. 1:0 Charcoal powder ......... Ee 6. Superoxymuriate of potassa....... 1:0 Sulphuret of antimony............ 10 This and No. 7 are fifth best, but they leave a hard cake of crocus of antimony, which adheres very strongly to the appa- ratus. | 7. Superoxymuriate of potassa....... 10 Sulphuret of antimony............ 1:0 The proportions of this powder were taken by volume. 8. Superoxymuriate of potassa. ...... 2°0 Dried charcoal powder. ..,...'.... 1:0 9. Superoxymuriate of potassa ....... 1:0 Dnied charcoal powder. ......4++. 1:0 10. Superoxymuriate ‘of potassa. ...... 3°0 | | Dried gunpowder .........6...0e0% 2:0 This is the best. 11. Superoxymuriate of potassa. ...... 1:0 Gunpowder, in fine powder........ 1:0 This is the second best. After numerous trials with these, their comparative regularity in producing the desired effect was calculated to be as nearly as possible, as has been noted in the above list. But I found that even No. 10 was not so uniform as was necessary for Col. Yule’s object. I had now, however, almost doubted of success, when it occurred to me to try the composition, which has since been found to succeed for more than 100 successive times, without leaving any,residuum to stop the firing. Of the composition of this powder, and some cautions necessary to be attended to in its prepara an account will be given in a future paper. t was with this powder that I performed the experiments, which presented those striking re of which I have now to give a brief account. I was led to these with the hope of elucidating still further than I had previously done a particular view of caloric, of which I have, for six years past, given an account in my chemical classes. Lavailed myself of the use of Col. Yule’s apparatus to commence the investigation, and I am still occupied with it. At reid an 1821.) an Apparatus for discharging Ordnance. . \ 93 present, therefore, it is only in. my power to notice,a.few of the: experiments in a detached form, i he first: experiments were performed by firing the new com- position, using about one grain, or rather less, at each trial, througa a piece of cartridge flannel tied over the hole at the. bottom, B, of the apparatus, when it inflamed a quantity of gun- owder fixed ina.tin case below the flannel. This was repeated. or many successive times without cleaning the apparatus, and the flame never failed to pierce the flannel and_ fire, the gun: powder, | | Should this succeed as regularly, when applied to. the gun, itself, there could remain no doubt but that it would possess. all the proposed. adyantages,. There was, therefore, fixed to.a. six- pounder, an apparatus similar to the one already described,; except that it wanted the long tube, A B, for which the priming. hole of the gun now became a substitute. It was charged witl cartridge, and in several of the trials with ball and cartridge;, and, upon the same experiments being repeated with it, it gave the same uniform results. , The next experiments were with the view of ascertaining how the results stood related to Sir Humphry Davy’s theory regard-. ing the impervious nature of wire gauze to flame. Wire gauze, of different degrees of fineness, was, in successive trials, put in. the interior of the joimings, a, 6, or c, of the tube, so as to cover™ the hole completely. When the coarser wire gauze, was em- ployed, the flame was found to pass through, and fire the gun- powder; but the same result never took place with wire gauze as fine as that. used in Sir Humphry Davy’s safety lamp, unless when the flame seemed to have. burst a passage through the gauze. But when these experiments were performed without the flannel and gunpowder at the bottom, B, it was found that the flame went through even three pieces of the wire gauze at once. 3 , The next: experiments, and probably the most surprising of the whole, were with gunpowder. placed in one of the divisions, ay 6, or.¢, of the apparatus. In some of the trials,,1 found that the flame had passed through the gunpowder ata, 6, orc, with- out inflaming it, although at other times | found it -did not do..s0..)) fy al _. This. at first appeared to be an objection to the proposed application of the apparatus. But, after repeated trials, 1 found that the above curious. result only took place when the stroke with the hammer was slight; for when a smart blow was given, inflammation always took place. . Ina few of the experiments, I put gunpowder at two divisions (@ and. 6), and found that the flame sometimes went through both, without«firing either portion; at other times one: portion was inflamed, and one left unaltered. In performing these experiments, I first put a small piece of 94 Col. Beaufoy’s Summary of the Magnetical and [Fes. flannel upon the hole at the joining of the tube, and upon this I oured the gunpowder, using two, three, four, and sometimes ve grains atonce. After each trial, I found a scorched brown- ish mark in the centre of the flannel about the size of the hole of the tube. : A variety of experiments were also performed with flannel, paper, and other substances, placed between the joinings ; in all which cases it was found that the flannel had been forced through, generally meee * hole in the substance used ; and a pale-coloured flame was observed to dart to a considerable dist- ance below the bottom (B) of the tube. In a future paper, I hope to have the honour of laying before the Society a fuller account of these curious experiments, In - that paper I propose to enter upon the cause of the results which resent themselves ; and more particularly to attempt an expla- nation of that extraordinary one wherein we have the gunpowder remaining apparently inert to the flame which passes through it. Articie ITI. Summary of the Magnetical and Meteorological Observations, during a Period of Three Years and Nine Months. By Col. Beaufoy, F.R.S. . ! (To Dr. Thomson.) MY DEAR SIR, Bushey Heath, Stanmore, Jan. 1, 1821. In the Annals of Philosophy for May, 1820, you did me the favour of publishing a table containing the monthly mean varia- tion of the magnetic needle for three years ; and in the letter accompanying it, I expressed my opinion that the maximum of the western variation at this place occurred in the month of March, 1819. With the view of demonstrating that this conclu- sion had not been precipitately drawn, I continued the observa- tions to the end of last year; and as the corresponding monthly mean variation in every case shows a diminution, I infer that the variation has been retrogade for the last 21 months. In the latter part of the protectorship, the true and the mag- netic meridians coincided. If 24° 41’ 42”, the greatest variation, be divided by 162 (the number of years since that period), the quotient 9’ 09” will be the mean annual increase ; it is reasonable to suppose, therefore, that after the same lapse of time (from 1819) these meridians will again coincide; but by inspecting Table II. it will be seen that the mean annual decrease in lieu of being 9’ 09” is 1’ 57”; consequently, an acceleration must take place, or the supposition is erroneous. i I remain, my dear Sir, very sincerely yours, Mark Beavroy. : 1821.] Meteorological Observations for Three Years and Nine Months. 95 9F-0— 93-0- c0-I- 61-0— cE-0— L&-6— 83-0— 90-1— €T-t— OIl-t—- 6F-3—- 80.6—- 1L-6—- 6L-E— 0¢-€— 16-1- G3-6— 8&-I— OL-I— PI-t— 00-6—- 10-€— OF-4— 8S-[— Ba - *eiead guasagip oyf Jo sqUot ottres st Ul WOHeTIVA 3u3 JO SsBOIDOP Pte aAseatoN! 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Ne ee ym eS yore "qd “ue Fe “6181 “09q "AON Avy Indy ‘SSI S& ly && Ov 6 FE 66 3 VE 6 S& VE 6 LE 6 1é 3% Ov 6 1é VE Fe Ww 2 €& 6 && 6 SF 3 1g 2 GS oF FS 1& 6 vE Fe er Ig 3% tS 6 oF v8 rs a cE tr 3 1S oFf% **usag ** WOON ee uo; **UOAT ** MOON ** uO **uaaq **uOON ** UOT "Uda **u00N "UOT **UaAq **uOON **UlOyW * uaa **mOON "Uuloy * "UdATT **u00N ** MOP **udATT * MOON * HOP * Uday **u00N * UO * *USATT **00N * MLLOP * Uday **u00N) **Uloy] “Waa **u00N "Uo Ne a a cs r,t Nt sat ae, pe Nm, ed Np als sa your yy qd "uee “SI8T 29 "AON pO ydag ‘sny fing oune Avy judy “LISI Adi “HOR MNT pun saved d044 Hof 2IpAN OHAUaY AT IYI Jo WoHDLW A UWL AyuopY Fuyuang pun ‘uoogy Fuyusoyy ays Fuymyvjuoy 4Q9L—"] AIAVL Mean Annual Decrease, 1’ 57”. Even,'24 33 10 96. Col. Beaufoy’s Summary of the Magnetical and [Een, | TABLE Il.—Table containing the Morning, Noon, and Variation of the Magnetic Needle in 1818, 1819, and 1820, a. ‘|Morn.'24° 34’ 38” Mom.|24° 33’ 06” Morn.|24° 31’ 16” 1818. Noon. 24 43 26 ||/1819. ~ |Noon.|24 40 52 ||1820, 2 Noon.'24 39 04 yen.24 37 10 [Even.'24 34 43 TABLE I11.—Table containing the Mean Monthly Diurnal Variation of the Mag- netic Needle, between Morning and Noon, and Noon and Evening, for Three Years and Nine Months. Months. 1817, 1818,/1818, 1819.'1819, 1820,|1819, 1820, Mean. 1817. ene ee: 12! 51" | 20” 44> 20" 39" | 94 g144 ar 00” | P Serco if 45 8 14 8 10 8 8I 8 25 ey” = 10 15 9 31 8 40 9 26 9 98 EUSA le Se 1-14 7 12 7 08 1 2 -( {Morn Yin 05 }> > et | 10 43 9 296 | 10 32 June | Noon: by 09 | 7:31 | 6 32 | 5 2881 6 45 Ae "are 10 52 | 10°35 | ~9~ 4r | 10-19] “10-92 wy Been? 6 23. 6 45 6 35 5 34 6 19 ie ote 11 35 | 11 18 | 10 16 9 35 | 10 Al one: en | ( 9-06}. 8 08. | 8. 25 6 46 | 8 06 Morn | jMom../’) g 34 .|..10. 53..|. 9 06 9 13 9 27 sone: {fxm § 58° | 7 54 | 8 06} 7 80 | & 3F bats ee: 9 40 | 1 52 6 41 8 33 8 jEven.. “7 i as ae 37E Wor tate 6 06 | 8 11 6 Ol 1 RS we Even as er en a 3 ae Dec - 8 59 4-16 | & 61 3 31 3 54 Even nae me we at wa 1818, |. 1819, Cites oS ee sk EP A Le 8s 8 i 4 28 4 Even.,. Rr Pi a ahi oy: ron ene 6 29 5 38 5 48 a 5 Bo. ‘Even "= re sa i 4 ‘Morn 4 /) 8s 419 | 8 9% 8 46 tl 8 30 marc {|Noon:| 3p 6 2 | 5 48 _ 6 4 . 1821.] Meteorological Observations for Three Y ears and Nine Months. 97 TABLE ‘IV.—Monthly. Meteorological Table containing, the Mean Height of the Barometers | Thermometer, and Hygrometer (De Luc’s), at the Hour of the Morning, Noon, and Kuening _ Observations of the Magnetie Needle. Also, the prevailing Winds, Quantity of Rain, Evaper. vation, and the Mean Heat of each Month, by a regular Series of Observation, with a Sixs: Thermometer. is a ‘Monthbs/Barom,|Barom.} Barom.|Ther, |Ther, |Ther. | Hyg. | Hyg. | Hyg. }Wind/Rain. Bvap cen Hi * 1817, {Inches.| Inches.} Inches. : Inch, | Inch, 29°770 |29-726 }29°762 | 42°79) 48-8°! 45-0°] 612°] 48°59] 50-0°] NE | — | — | — May {29 286 |29-269 | 29-286 | 50°1 | 57-4 | 50-2 | 58-2 [52-9 [53-6 | SW | — | — | — June [29-410 }29-422/ 29-439 | 61°1 | 68-3 | 62°0 | 60°8 | 48°7-152°3 | SW | — ~ 4. July [29-368 [29-612 | 29-349 | 56-7 | 65:3: | 59°4.].64:3. | 55°2 [59-21 SW | — | — [59-3 Aug. {29°310 |29-320} 29-322 | 57-3 |63°0 | 59-1 {| 66°9 | 54°6 |57-1 |] SW | — | — 158-9 ‘Bept. {29516 |29°522|29-489 | 56°4. | 62-5 | 580 |70-9 | 547 |60-9 | NE | — | — j584 Oct. [29°541/29°475| — 143-0 |49°6 | — | 65-4 1566 | — | NE| — | — 1446 Nov. |29°518/29:501f — |45°7 [51-2 } — | 78-0} 68:0.) — |}. NE.|.— |. — |Aut a 29°130|29:121}° — | 35°4:|/38-0} — {7821660 | — | SW | — | —./85-9 818, i 6, Jan, |29-227/29°387} — {37°6'/41-2 | — | 75-1 /68°8 | — |} SW} — | —o/37-9 Feb, /29-272 |29°286} — |32°8 137-3} — |74:3]/659 | — | SW; — | —./34-9 March | 29-154 |29-132|29°497 | 37°6 | 43-6 | 39-8 |661 {57:2 | 51-4 | SW | 2-330) 2-570 39-7 April |29°241 |29:294 |}29°322 | 44°5 | 49-9 | 46:1 }629 |51°7 | 55:0 | NE | 3-750) 2-590) 45-8 May /29°393 |29:463}29-423 | 51-7 159-0 | 53-4 152-2 [42°1 |47°1 | NE | 2-453 3-770! 52-8 June {29-597 |29:586}29°610 | 62°8 | 715 | 65-2 143-1 | 32:7 | 37'S | SW | 0-330 6-980! 64-0 July |29-629 |29-621 |29-625 | 65°8 |73-3 | 68:1 [43-8 |33°8 | 37-7 | NW /0-670) 7-015! 6791 Aug. [29-625 |29°605/29-611 | 62°3 |68°S | 63-1 | 41-3 |30°4 |S2-2 | NW |0-491 7-030 62°5 i Sept. [29-346 |29-326|29°357 | 54°9 [62-2 | 58-1 461-1 44:6 | 51-1 | SW | 3-120) 3-400) 57-7 ‘Oct. [29-411 |29-391] — 151° 157-9-} — {70:4 457-1 SW | 1-384) 1-970 53-8 Nov. /|29°394 129-357} — [465 |51-4 | — {77-7 |65:2 |} — | SW | 2-412 1-080 46°7 Dec. {29-611 |29°607} — | 35-6 1398 | — |79°5 [65:5] — | NE /1-215 aes aed 1819, Jan. {29-670 /29:301] — 36-8 [42:3] — {81:5 [635 | — | SW | 1-906) 1-400 38-9 Feb. [29-172 |29°166} — | 38-2 [426] — |72°2 {55°9 | — | NW | 2-828) 1-480 38-8 March |29-386 |29-682} 29°333 | 42°0 |46°8:| 46-3 | 65-3 | 52°2 | 51-4 | NW | 1°143) 2-680 41-6 April |29-321 |29-332| 29-329 | 49-0 {52-7 | 48-7 [53-5 |40°6 | 49-6 | SW | 2-468) 3-440 48-5 May 29-440 |29-435| 29-489 | 54:8 {61-1 |55:5 [48-9 4373 | 44-2 | SE | 3-063) 4-530 55:3 June [29-462 |29-452] 29456 |.57°4 || 62:2 | 57:3) 153-5. | 44°6 | 49-8 | SW | 1-950) 4-250 57-2 July | 29-233 |29-539] 29:556 | 62-1 | 68-7 | 63°0 [57-0 |44-9'| 52-2 | NE} 1514) 4-930, 64-4 Aug. |29°599 429-579} 29-565) 62S |70:9 | 65:1 | 669 | 48-6 | 60-0 | NE | 2°520| 4-720 64-5 Sept. 29:511 |29°518] 29-519 | 56-7 | 62-9 | 58-1 179-2 | 64-7 | 67°35 | SW | 3-213) 3-550 57-9 Oct. (29-370 |29-362) — | 47-7 | 53-1 | — 1799 68:9 | — | NW/| 1-610) 2-280 49-1 Nov. {29-253 |29-233| —. | 37-4:/420] — {799.1728 |. — | NW. 1-761) 1-230, 39-8 ies, 29-243 |29:288| . —. | 32-4 | 36-4]. — {82:9 175°7 | — | SW | 2-429 '0-710: 34-6 Jan. (29-372|29-402] —— |o8-8 |39-1] — |900173:9 | — | SW | 1-020) 0°360, 31-3 Feb. |29:518429-479| -—. |30-4 |387 | — {82-9 [74-1 | — [ NE |1-143/ 0-765 35-6 March |29-408 |29-439 |29-295 | 37-6 | 44-5 | 46:3.174-2 | 63-6 | 67-4 NW | 0-246) 4-170, 40-7 April |29-470 |-9-474 | 29-517 | 47-9 |55-6 | 51°6 167-5 | 59°3 | 63-3 | SW | 1-505) 3 750 49-5 May |29-375 {29-352 129-339 | 51° | 58°8 |53°8.166-4 {53-6 | 63-4 | SW | 2-383) 4-270, 53-4 June |29'490|29°438 }29°393 | 57-1 | 63-4 | 58:3. )69°8 | 53-8 | 645 }/NW-1-724/4:390 58-1 July 29-519 129-530 {29-458 | 60-3 | 65-7 | 0-5 | 69-1 | GU-L | 67-5 | NW | 1-936 3.959, 60-7 Aug. |29-461 |29-468 |29-443 | 59:3 | 65-6 | 601 | 70-5 | 59-8 | 63-4] SW [1-002 4-820 61-1 Sept. |29-550 |29-543 |29°595 | 53-8 6141]. 563: 171-2.}57-9-| Gi-L.| SW. | 2-283,3-400 55-2 Oct, /29-200|29-166} — |45-6 }51-4 | — ]71-8j 61-9 | — | NE %\2-538) 2-500 45°5 Nov. {89-371 29-371) — |39-7 144-0 | — [467% | 70-0 | — | NE | 1-223) 0-853, 41-6, — |36-6 439-2 | — |75:9 | 72:5 | — | NE | 1-468] 1-133) 38-6 Dec. | 29-467 }29-449 New Series, vou. 1. G 98. SEadi ‘e- Mr, Adams on. oy) . [Fes. TABLE V.—Annual Meteorological Table of the Mean Heights of the Barometer, &c. §c. Year, |Barom, item. (Hacom. Ther, | Ther, |Ther, | Hyg. | Hyg. | Hyg. |Wind.| Rain. | Evap. eee Inches.| Inches. | Inches Inches.| Inches, . 1818, |29°408 |29-421 |29°482) 48°79) 54+3°} 56°39) 59-29) 51°39) 44-691 SW | — — |50°0° 1819, |29°389 |29-407 |29°464| 48-1 | 53-5 | 563 | 68:4 155°8 | 53-5 | SW |26°415/35°150| 49°83 1820, |29°433 |29°426 |29°434| 45°7 151-8 | 55°3 | 73-0 | 63-0 | 64°4 SW_ /|20°460'34-362| 47°6 TABLE V1I,—General Table of Winds. Years. | NN. | NE. | £&. | sz. | s.. | s.w. | w. | N.w.|Calm.| Var. —_— = 1818.| 24 172 61 119 28 300 75 157 | 36 8 1819.| 19 208 42 117 32 262 78 216) 7 | 19 1820. } 38 215 -| -38 104 21 285 77 |. 204) 4 | 33 Mean} 20 198 47 113 27 282 17 192 | 16 | 27 All the Winds between the cardinal points are described as N.E. S.E. S.W. and N.W. The number of observations in each year exceeded 850, but for readily com- paring the results, the Table is calculated for 1000. ArtTIcLE IV. On a Method of applying Maclaurin’s Theorem. | By Mr. James Adams. (To the Editor of the Annals of Philosophy.) SIR, Stonehouse, near Plymouth, Dec. 30, 1820. ConsiDERING the following method of applying Maclaurin’s : Theorem (see his Fluxions, vol. ii. p. 198) as an improvement, I will thank you for its insertion in the Annals of Philosophy. | I am, Sir, your obliged humble servant, James ADAMS. | - te i j . Problem—Givenu = A + (Bz 4+ C22\+ D2+4+ E xt : F z* + &c.) 4 ao eS age te Weg oe ’ j To find mae — > &c. supposing d z constant. ' q . A By taking the successive differentials of the given equations, we have 1821.] «a Method of applying Maclaurin’s Theorem. 99: we =A+ (B2+Cx2?4+De+ E+ F 2+.) =At fz ““—- B+(2C24+3D24+4E24+5F2t+ &.) =Bt+ fz PY = 204 2.3D24+3.4E24+4.5F2 + &e) 2° 2C+f1,% | S#=29:53D + (2.3.4Ez24+3.4.5F2 + &.) = 2.3” D+ fiir z | See i Fog Bet (23.4.8 Rec. B. 6 Gx + &e,) =m2.3.4E 4+ 62 P23 4.5 P+ 2.35415 6G2 + Re)... 2. 3.4.5 F + ¢,2. Where fz, f, z fir %>firi&y % %) F, %, Kc. denote different func- tions of x. Example 1.—Let it be required to develope uw = (a + 2)". ws (a-+ <2)" = a” +fze=Atfze.a™= A. . ad = = m(a+z)*"' = = ma™—? + fi % = B+ f,z . nat ZB, au d 2 = m(m—1) (a+z)"~* = m (m—lha™ P+ ff,%=2C + Su z..m(m—1) a"—? = 2C, Then by writing the value of A, B, C, &c. in the problem, m(m—1)a"—? ae we have (a + zs)" =a" + ma™'2% + m (m — 1) (m — 2) a™—3 Le * 1.2.3, x? ot Ke. ot * The usual method of finding the values of A, B, C, &c. is to suppose the variable quantity in the given equations equal to nothing, by which means other equations are obtained which determine A, B, C, &c. in terms of the given function; thus in the equation wu = (@ + 2)™ = A + Be +C 2+ D223 + &e. Suppose ~ = 0, then gn = A, d u, — =m (a+2z)"—! = B+2Cz2+3D22+ &c. Suppose z=0, then m a™—'= B, a as io” (m—1) (a+2)™"—-? =2C+2.3D2z + &c. Suppose z=0, then m on—1) a™—? —2C the same as before. This latter method is evidently as simple in ite application as the preceding, but it does not appear to me to be so evident, particularly to beginners. If 0 be written for z in the equation « = A + Bz+Cx?+D23 + &. : ; du Pu d u we should have w = A, a given quantity, therefore ——, ere ee 3 Ke will be Tespec- tiyely equal to nothing. : G 2 100 Mr: Adamson Bin. mye wu =—= (a + x)™ ii i A ry o Ate, See (at 2) = — a + fixe Be fixe Ba= 5, a be od 1 Se = 2+ 2) Fee: 2 a + fut = 204+ fi 2 -.C = sy, He = — 2.84 2) — 2.30 t fy me =2.3D + l Siw ® + D=- mr BOR. 5 kgdb be CTR ORE RO a ee EA Bh Cae Therefore, by writing the values of A, B, C, die: in the are blem, we have et 5 5+ ke. Example 3. To find the log. (a +.) in a series, log. of base” unity. u=sl(at+z=l (1+ =)a=s/(1+*)+la=la+ JRA ES, —ta=A. . du 1 1 reap athe B then g= B, ad? u 2 —2 ee - ata) 7=-a + fixe dC + frz a a 2C, au e at 1 ae 2a + x) P= 2a tt fiz = 2. oD A fig AO - 7e- = 3D} BEL. see's Sip occ cuceepuehunn vie op ds digegece ate Bieioweh Mpikion > aad om By substituting for A, B, C, &c. we have 2? 28 log. (a+ z)=l. a+-—S.+55 7a + &e. Example 4,—To find the log, (a — x).in a. series, log. of base being unity. wistl(w—sz) = i(\ —Z)a=l.a +fxumA+t fav. A=l.a, Gen at E+ fhe) eB the Be) a ~ com — (at Sut) e PC thus Osi p= oop = — Gt hut) = 2.3 D+ fired == sy 1821.) a Method of applying Maclaurin’s Theorem. 101 By substituting for A, B, C, &c. we have & i rx log. (a2) =. a Gtretaet re i) ‘Example 5.—Expand into a series the log. (~~ -) log. of base unity. = lg a CAS gl ce nz thee (af eBt yada Papp ta thie = 20 + faz 2; ae Poe-o=- (5+ fine) =2.3D4 fiz 0D Sgt ELE tide Fe cede. t.dase oe EX otewsd, te dh & E ema ipne este eigen che © Hence, and by aaa. we have it g? 43 4 log. (3) = 1 4 ga ti Be. Example 6.--Expand into a series the log. (=): log. of base unity | , l fl uo Hl) et) + fas Act fark i 3) d 1 1 Set he aBt fiz. “B=, z a. i { 1 eA aap a tHe BC + ft - C= oy Bu 2 1 fat wop tats = 2: -3D + fir % * D= sy &e. eeeevoeeveeoseseovoe7 ee © @ @ @®@eseeoeveeeeeveeee eevee os ee es @.8 0.00 ©.¢ 6:0 @ ee and by substituting in the pores we have 3 log. (= —)a( +4 Psa ee + ga FOO Example 7,—Expand into a series a*, log. of base-unity. “= @i= {1+ (a@— )Pelst fas A tsfesr Awd, “* -lafl+@—)D¥ =lat+fc=B+fjc-.Ba=l.a, ax FR = Coot 4 @- bys Cah t+ firs 2 + fiw C= Ce a Saal. ap il + @—D¥ =. a) + fire = 2-3D + ly Tie” ie: eo -, &e. SHAT Ra dies Shoes Ves Ae esl 6 kod bod ae oan 6 eee 1102 2 Mr. Adams on tei offs. By substituting for A, B, C, &c. we have Lease y Wohee Wadia | Cotes ge ve rt ies r.2.8 + 1.2.3.4 Example 8.—Expand into a series the log. (= =) log. ofbase unity. i w =I(=*)=lltfes0tfrsAt fre. A=0, asx du 2a 2 2 go tweet TT thr HBt+ fc. B=-, a 4 Ta @op HOt fur a2Ct free C= 0, au Aa 16 aa 4 aa @-2 (@—a%s — a te Say ee 20 3D + fuz v“D 2 3a” @u A8axr 96 a x3 , ax — Wa» t roam = 0 + fy # = 2 . 3.4E + fy ® a Ms @ u 48 . 4S: ‘ ta Gop thea tfucrH2.3.455F + fu. 2 , Foz, &ec ee ete eer eseeeeeeesrer eens eeeseseeeeese eeereseene eeee By substituting for A, B, C, &c. we have a+2 r x x a log. (== sitsattetiet Ke.) | By adding the series in Example 3 to the series in Example 6, or subtracting the series in Example 4, from the series in Ex- ample 3, we have the same result as above, which is evident from the nature of logarithms. | Example 9.—It is required to expand into a series the expres- am— xm sion - a « u == sa"! + fois A + fiz ojAi= a*7', du an— zm alate as Sap ors Are fet = Birk fic Baeatt’s See fi pie 2a oy face 20a fae. C =e ast (a—2)3. renee ee Pe Pere re ERE RED NA NIE Spa bo Weitee. abe By substituting for A, B, C, we have a =z" a~—-z =a" (1+ 24 (=) + Gy tf.) 4-2 = a™~' + a®—*2 + a" —) x? + arate’ + Ke. Or, © 1821.) «a Method of applying Maclaurin’s Theorem. + 103 Lemma.—To find. the sines, cosines, tangents, Kc. of circular arcs in functions of the arcs, radius being unity. Given sin. x = function of z = fz, then will cos. % = (1 — sin.2 2)" = | —f, Rs sin. £ Sf 2 PM ede SL ee ut By 1 ] cot. 3 = ——— =, tan. 2 of, % ge0¢: 2 Se a ccd 4 fii. OT Seon: Bh ee re 1 1 cosec. 2% = sin. £ : Fe Example 10.—To find the sine of an are in terms of the are, radius unity. %@ ==. 8In. z=O+fxe=At+Be+C2X+ D2 + &. = Ab fie tcA =. , “* Scos.z=1l-—f.x=B—f,2-.B = 1, dz d? —=.— sing = — OF fir) = 2C+ fi ze. 2C=— 0, d® u ie. of oe (1 — fin 2%) =2.3D — fier. 2.3. D= —1, &e. eoeeeeeveeveeeseseeeeveeeeesveaeeaeseeue Beene ee & @eeees ° e e e By substituting for A, B,C, &c. we have * ; 23 29 ane Bo eh oe ag Example 11.—To find the cosine of an arc in terms of the arc, radius unity. u =cos.%=1—fz=A—(Bz+ C2? + D2 + &c.) mA— fz. Ax I, sy Er snez = -—O+f2) = B+ f,z-.B= —O, a —~=—cos.z= —(1—fi,2) =2C—f,2+.2C=—1, dt J —=sinz=O04+f,,2=2.3D + fi.z-.2.3D =0, t= co.e =1—f,2=2.3.4E—f,22.2.3.4E= 1, he eee Kia FUE SRO NRT NC d ahs WALA by heme weeny bce osee By substituting for A, B, C, &c. we have 32 a4 go oe iat ta ee lk Ske Example 12.—To find the tangent of an arc in terms of the arc, radius naatp 6104 “esol Lents aR Adamson WoAshhw “Res. (ur tans 2b 0 + fzm At fa fa BBO, wrnsesc 2 maphe a: Mee Pate = ly SSS Qtt WoO frwrH QC tfuz.. C= 0, — = 2+ 82 46S le foes S2 FD f,,,2-.D "ek. ee —— = 16¢ +408 + 24 =O fpx = 2 93°4E + fiz E = 0, S16 +136 #24 240 #4 +.120 0° = 16. + fpmm® 3. 16 ‘e's AE + Aes- 1. oan Be? Ke. e*eeeseee Coe ee es vole sosccesiee 6 veo ce 06. 0s ¢ onpe See eee ce From whence, and by substituting in the problem, we have 22 1625 p fONs. bh eh meee get Xe. Example 13.—To find the secant of an arc in terms of the arc, radius-unity. 3 & ==. dee, ‘2. = 7] + fen At fe: .A =l, pri tick Set pe ke 0 +fx= B+ fi2.. BAO, ot = eee tke SL tf eH 2C4 fiz vated, Gem iaeit ti, Seabee + tee ke, =O! +i, SERS DHF, 20D = 0, Ott et Ke Ft fz = 2.3.4 Evt f, aE = sop So = 61 t+ SE 4 Sot Ke 0 tft = 2-344.5 Bot f,z.. F-= 0, oe = 61 + So ke HR Ol t+ fee =2.3.4.5.604 a 61 fo so. G = pomp &e. eetveevewveewnreereenereeenenvnneeeet ee @wneecewee eee e eG eeewe eee ee H h 1455 4550 tress CHEE, WE DAVE SECA S Fy hy ple MF sa Swe .5.6 + &e. 4 1821.) a Method of applying Maclaurin’s Theorem. — 405 The student: must understand. that the developement of a func- tion by the preceeding method us not always the most conve- nient ; forinstance, Examples: 12 and 13 may be'answered in a more simple and general manner by note. N (with,some slight alteration in the symbols), taken from the translation of Lacroix’ Differential and Integral Calculus. x3 x x7 x a OE eee 6 OTT cos, £ ~ a x4 x nd Ren es ites lis 2 ip i, 24 ee es Be stig Per trig. tan, v= radius unity. 1 1 I 1 1. 2? b= iy “va aaa re a= i.e 1 1 poe JS = 77 &e. the above equation becomesitan. x = By writing a = r—b23 + dx5—fxuxit+ hat — &e. l—az?+ cxt—erk +g c* ~— &e.° Now from a little attention to these equations, it will.appear that tan. w may be represented by the series A x + Ba® + Ca5 | + Da? + Ea? + &e. wb 28 + dad — fal + hiad — &e. that Tn a dea —_ + ga®— &e, + Da?+ Ex? + &e. From whence we get =Azr+t+ Ba? + C 2k CA @ (B—A a) x (C—Ba+tAc) 2x (D—C a+ Be—A'e) 2? (E—Da+Cc—Be+Ag)a® BG eh bse 'é.s «4 ced 6 eu s eee Then by equating the coefficients of the corresponding powers of « on each side of the last equation, we have a—ba+dae— fxi+ hap Beec sg A=1, ! 2 B=Aa—C=7>,, C=Ba—Ac+d=,~, D=Ca—Be+Ace—f=;, E=Da—Cc+Be-Ag Phar, | &e. ae eevee eoeeeeeves even ee ee eevee % 6 @ ee e8@ee08 oee eee @ The law of continuation being evident, we, therefore, have 2 x8 (LG (48. VIP a7 1936 29. ,, 4% 220.3 Tins yA pees Loe cane The same method may;be applied to:the developement of the cot. 7. ah. 2 = 7 + COF0G = swvooll oprah a) Adamson \o bolle» fF ifBen. ns 20 dae cos.) lea@at+cat—er’ + gat &e. alll _ For cot, Sat sine ot — bad + dxs— fal + hay &e. ro — (Aw + Be + C a+ ae Oe veh 0 ~From whence we obtain r(—A—b) x* (—B+A 644d) x* mat +cu—erv+gx—Ke, =< (—C+Bb—Ad—f) 1° “iA (—D+Cb—Bd+Af+h)a* Then by equating the homologous terms, we have = (a—6).= 5, Be +Ab-—(-—d=z C=-—-Ad+Bb+(e=— zane a DS "yY APO |B d+ Cb —'(¢— h) = &e. eeeeveereeeerereeeevreveevenee eens eoereeeeevrraee ee ee aeeerseeeee Where the law of continuation is evident, we piahads ae have 1 x x3 2 x5 : cote = — (P+ 5 +o + + Ke.) | ; 3." 45 * 945° 4725 | In like manner we may develope the sec. x, 1 1 sas pret =1+A2°+ Send cos, © li—aa*+ cat —ex' + g a* — &e, Bat +Ca*°'+ Da + &c. radius unity; from which equation we obtain the following, viz. r(A —/a) x* (B— Aae c)jat 0=<(C— Ba+A.c—e) 2 (D—Ca+Be—Ae +g) a* L Weitow che Mie piane s/s od-0 9 > weed doe b Then by making the coefficients of x*, 1+, 2°, 2*, &c. respect- ively equal to nothing, we shall have A=a=;, B=Aa-c=2, =—Ac+Ba-e=<, D=Ae-—-Bce+Ca-—g= pode ian Saipan Se L . “Wer ee eo ae 0 oeRIeghae 9.0 The law of continuation being evident, therefore, eee. ges: 7 = ae toe + oe + Ke. 1821 J a Method of applying Maclaurin’s Theorem. 107 We may fromthe same principle find the cosec. x in terms of the are x, radius, unity. £2 , | 1 1 1 CPPS EAE oi sm 2 a bat + ada fal hat—&c- +Aa+ Baw + Cx + &e. From whence we get PA = bye 1(B.-— Ab + d) a O=~4(C—Bb+Ad — f)x® \D—Cb+Bd—-Af+h)2’ UW. aaa a wad San aisle wiggle ve ule’ Then by making the coefficients of x°, x*, 7°, a*, &c. respect- ively equal to zero, we have : 1 A=b=,, , 7 “C=Bb—-Ad+f=—5, D=Cb—~Bd+Af—-h= Xe. eoeee@eseeee eevee ee © @ .e é eoeeet eevee *e eo @ eeeveesve8 eeeeee eee The law of continuation being evident, therefore, 7 x3 31 x 127 2? 360 + isizo + Gorso0 + Xe- ; 1 x cosec. P= — +5 + ARTICLE VY. On the Solution and Crystallization of Lime. By R. Phillips, FRSE.FLS. &c. Mr. Darton, in his ‘‘ New System of Chemical Philoso- _ phy,” has stated the curious fact that lime is more soluble in cold water than in hot, and has given the following table to show the difference which exists in water of various temperatures. One part of water of Takes up of lime. Takes up of dry hydrate of lime. 60° @eee eee she e3 eees 7G 8 eeeseeeseeneteeree 3 130 eereeeevrererv ee LS eeceoeveeeveoee ee shy a9 ereeeneveee eee Tot @eervovnee8ec e 952 “This table,”’ he observes, ‘ leads us to conclude that water at the freezing temperature would take nearly twice the quantity of lime that water at the boiling temperature takes.” Mr. Dalton has not attempted to account for the curious fact | which he has discovered. . Mr. Brande has not mentioned this 108 _ (Mr. Richard Phillips onthe. [Fxs. ‘ cireumstance in‘his Manual of Chemistry, nor does Dr. Thomson or Dr. Henry attempt to explain the fact’ in their, respective works, although they have’ given the results of Mr. Dalton’s experiments. Dr. Murray, inthe last edition. of his System of Chemistry, observes, “‘ this circumstance is extremely singular ; augmented solubility from cold is contrary to all analogy, as;well as to the principle on which the relation of temperature to solu- tion depends.” With the intention of determining the comparative solubility of lime in water of different temperatures, and if possible also to discover the cause of the diflerence, I prepared some lime- water at the temperature of the atmosphere, which was then about 60° of Fahrenheit.. A wine pint which had been filtered with as little exposure to the atmosphere as possible ‘was decomposed by adding solution of carbonate of ammonia. The’solution was examined with oxalic acid, and it appeared that the whole of the lime was precipitated by the carbonic acid of the carbonate,of ammonia. The precipitated carbonate of lime being washed and dried weighed 17:3 grs. equivalent, according to Dr. Wol- laston, to 9°7 grs. of lime ; and as a pint of lime-water weighs about 7300 grs. it follows that water at 60° dissolves about 3, of its weight, agreeing pretty nearly with Mr. Dalton’s state- ment, and ‘still more ‘so -with Dr.. Thitenson’ who finds ‘that “ 758 ers. of cold water dissolve one of lime.” I next boiled some hydrate of lime in. water,’ and filtered it with as little exposure to the air, and’as rapidly as possible. A pint of this decomposed, as in the former case, by carbonate of ammonia, gave 10:5 grs. of carbonate of lime, equal, according to the scale, to 5°9 grs. oflime. Boiling water, therefore, as appears by this, dissolves only +4, of its weight of lime. I repeated this experiment, taking.exactly 10,000 grs. of the lime water, the carbonate of lime weighed 14 grs. = 7:8 of lime; so that “the hot water had taken up +,,, of its weight, agreeing very closely with the former-experiment, and as nearly with Mr. Dal- ton’s.as 1280 to 1270. Some lime water was now prepared by putting ‘hydrate into water, a very little above the temperature of 32°. This: bein ‘filtered with the usual precaution, 10,000 gers. were decompose in the manner already stated, and 27 grs. of carbonate of lime were obtained, confirming very, nearly Mr. Dalton’s opinion that water at 32° would dissolve twice as much lime as water at 212°: 27 gts. of carbonate of lime are equivalent to 15:2. of lime, and consequently water at near 32° dissolves 1, ofits weight of lime : to be exactly double, it should be ,1,. Having, by these experiments, satisfied myself of the correct- -ness of the facts stated by Mr. Dalton, I proceeded to:imquire into their cause. With this intention, I prepared some lime -water at a little above 32° of Fahrenheit, and heated to ebullition “46 ounces in a flask, from which a long tube issued:to prevent 1821.) . Solution and Crystallization:of Lime. 109: the access of carbonic acid from the atmosphere. In a very ; short time, small white particles were dopbanen inthe lime water; and after about two ounces of the water had been evaporated, I. discontinued the ebullition, and’ cooled the lime water secured,: from atmospheric air. On examining the particles which had: been deposited, it was; evident that they were crystalline, although the smallness pre vented the determination of their form; they had nevertheless. the usual brtilliancy of saline crystals. To ite quantity of lime had been deposited by crys-. tallizing, and what proportion it bore to the evaporation, I decom~ posed a pint of the lime water in the mode already described by carbonate of ammonia, the carbonate of lime precipitated was dried, and weighed 8°6 grs. = 4°85 ers. of lime. It is, there- fore, evident that the action of the heat had caused the crystalli- zation of the lime, and had effected it in a much greater degree than could be accounted for by the evaporation which occurred: The lime water before evaporation contained ,1,. of its weight of lime; after 1-13th had been evaporated, the quantity of lime was reduced to —4.; so that more than one half of the lime was crystallized by evaporating 1-13th of the solution. The cause of this crystallization appears to me to result from the effect’ which heat sometimes produces of increasing instead: of diminishing the attraction of cohesion. The affinities which. are brought into play are, the’ attraction of aggregation of» the particles of the lime for each other, the attraction of the« lime to form a hydrate with a small portion of water, and’ the: mutual affinity existing’ between that hydrate and water of. solution. ; Among the cases which may be cited as proving the aggre- gating power: of heat is this: If some’ peracetate of irom be decomposed: by ammonia, the oxide is quickly redissolved by: acetic acid ; but if the oxide of iron be boiled in the’solution: from which it is precipitated, the acetic acid is incapable of dis- solving it, on account of the cohesion which the oxide of iron: has suffered by heating. As crystallization is but a modification of ‘cohesive affinity, we may, I think, consider, that the cohesive’ or crystalline affinity’: excited by the heat, increased’ by the affinity of the lime for a definite portion of water, is so much greater than the afhi- nity of the hydrate of lime for the water of solution as: to occa» sion crystallization. Ifthe quantity of lime crystallized’ was/in any degree proportional to that of the water evaporated, there: would be’ no occasion’ to: suppose the existence of ‘the cause | have mentioned. | Mr. Dalton, instead’ of merely heating lime water, which had been prepared 'at a lower temperature, boiled it again with hydrate: of lime; itis evident, therefore; that the crystallization which he would otherwise have observed could not be‘adduced to account 110 © Mr. Richard Phillips on the > [Fes. ; for the curious discovery which he had made.. Although I was aware » of the crystallization of lime which M. Gay-Lussac had effected . by the agency of sulphuric acid and a vacuum ; and after I had looked in vain to the authors whom I have quoted, in order to . discover whether they were aware of the crystallization of lime which takes place by heating, I found that M. Thenard had stated the fact in his Traité de Chimie; however as he has not given any account of the extent to which it takes place, nor applied it to explain the greater solubility of lime in cold water, I have thought the details now given not altogether devoid of interest. ArtTIcLE VI, On the Bicarbonate of Ammonia. By Richard Phillips, | RSE. FLS. &c. In the seventh volume of the Journal of Literature, Science, and the Arts, I have given an analysis of the salt usually called subcarbonate of ammonia. I traced also the nature of the decomposition by which muriate of ammonia is converted by . the action of carbonate of lime, first into sesquicarbonate, and eventually into bicarbonate of ammonia. This last salt I had not at that time seen produced, except by exposing sesquicar- bonate of ammonia to the atmosphere. During the last summer, however, Dr. Henry gave me some salt aihich bat been prepared with the intention of producing the common smelling salts. From some cause which has not been explained, the salt instead of being pungent had scarcely any smell whatever, and was on this account rejected by those to whom it was sent. This salt is more crystalline in its texture than the sesquicarbonate of ammonia: it does not become opaque by keeping ; and turmeric pare held over it is scarcely affected by it even when fresh roken. Dr. Henry informed me that he had found this salt to be bicarbonate, but not having given me the particulars of his ana- _. lysis, I venture to state the results of my own experiments. One hundred and twenty parts of the salt were dissolved in dilute sulphuric acid, the weight of the vial and acid being pre- viously noted. The quantity of carbonic acid evolved amounted to 66°6 parts, equivalent to 55°5 per cent, An equal quantity of the same salt was dissolved in water, and added to a neutral solution of nitrate of lime, taking care that the latter salt was excess. Effervescence readily occurred, and by the application of a gentle heat, carbonate of lime was precipitated : this after being washed, was dried, and weighed 74-4 = 62 per cent. By Dr. Wollaston’s scale, it will he seen that 62 of carhonate 182).] | _ Bicarbonate of Ammonia. IL) | of lime are equivalent to 21:16 ofammonia. One hundred parts. , of this salt consist, therefore, of | CAMDOIIC BOIL, w+ 00 86 tre.5 ko > 555 AMMONIA. cece cere cree ot 16 leaving for WEEE As 6 oe 2 0 9 214 vine de bee 9s CUE ia 100-00 The exact composition and atomic constitution are as follow, , and perfectly similar to the salt obtained by exposing what is usually termed subcarbonate (but correctly sesquicarbonate) of ammonia to'the ait. Two atoms of carbonic acid. .... 55°08 ...... 55°5 One atom Of atimonia oe Oe RT 62, oS OL ‘LWO atoms Of Water... cc cc cee ee Oe OR TE SSDS BOaR Sees 99°22 100:0 ArticLe VII. On Rain-Guages. By Mr. Richard Davenport. (To the Editor of the Annals of Philosophy.) - SIR, | Jan. 10, 1821. I PERCEIVE in your last number another letter added to the . many that have appeared on the subject of the different indica- , tions of similar rain-guages differently situated. It is rather surprising that the writer should not before have met with the observation that a greater quantity of rain falls on a given area on the surface of the ground than on an equal area at a consi- derable height above it; it being noticed and accounted for in elementary books and lectures on meteorology generally. {t is more surprising that disputes should have arisen and have been carried on from time to time in a scientific publica- tion, whether, on a given area, an equal or a smaller quantity of . rain drops would be received if falling obliquely, than when fall- ing perpendicularly, ceteris paribus; it being a subject of easy demonstration, and probably by the greater part of your readers perceived to be so, although some of the disputants seem to continue in their first error. : - There is, however, a cause of the different indications of simi- lar rain-guages under the circumstances that have led to the, discussion, which I have not seen any where noticed, and it is for this reason J trouble you with this letter. oTf we suppose rain drops to proceed at uniform relative dis- 112° Mr. Davenport.on Rain-Guages. [Fes.. tances: from each other out: of a cloud of given» magnitude’: extending horizontally over a certain area of land, whether those rain-drops fall perpendicularly, or proceed with a motion derived from a projectile force received in the upper regions, the lines described in their fall will be parallel to each other, and the space they fall on on the surface of the earth will be in either case equal,to the area.of the cloud: in one case, immediately under the cloud; in the other, at some distance from it. In either case, similar rain-guages would receive equal quantities with each other. This cannot admit of serious dispute; but when we consider that the oblique fall of rain-drops is given them by the motion of the medium through which they: pass, and that. when that medium (the wind) with its rain-drops impinge; against any. opposing. surface, the rain-drops, are retained by that surface, while the volume of wind proceeds dis- charged_of that rain, the case is altered; for it becomes evident that anieddy of reverberated wind | contains a smaller quantity of rain than is contained in an equal volume of uninter- rupted wind. — Suppose now a wall extending on a plain, and the rain in its oblique fall beating against the face of this wall, and two rain- ages, placed one on each side of the wall at the base, and a third on the top. If the oblique direction of the rain were owing to anosoriginal projecting force, one of thoseat the base would receive no rain at all; but the other, and the one at the top, would receive equal + with each other (putting out of question the: trifling difference of accumulation of drops falling through the small perpendicular space between them) and those pore ip would be equal to those of similar guages placed on e uninterrupted plain. - But since the oblique direction is: owing to the horizontal motion of the stratum of air through which the rain passes, we ought to expect the: upper guage to receive less ; for the volume of air that beats against the wall is. not annihilated, but must rise ; and — over the wallpasses: over the upper guage discharged of rain, driving away an:equal volume of ‘saturated air: We may also expect the one«at the base even at the windward side to receive fam than others ati a distance from the wall, for part of the wind must be reverberated: over that. In short there will be a general mixture and confu- sion of saturated and emptied volumes of air disturbing the indications of all the guages within the influence of the eddies of wind. , Take another case.—Suppose an extended plain abruptly broken by a perpendicular cliff into two different levels. Say, a cliff running’ from north to south, and on the west side ofvit a high level plain, and on the east side a plain on a lowerlevel: Place a rain-guage on the edge of the cliff. Suppose a driving: rain with a west wind. This guage will receive: its due quantity of rain equally with others on the open plains. But suppose a 1821.] Machine for measuring a Ship’s Way by the Log Line, 115 driving rain with an east wind. In this case it ought to receive much less, because the face of the cliff will receive all the rain contained in the wind driven against it, and will drive upwards the wind discharged of rain, If the wind drives up a slope, instead of a perpendicular wall or cliff, the same thing will hap- pen in a less degree; and all irregularities of surface will more or less disturb the equality of distribution of rain; and that in different degrees under different directions of the wind. It is also evident that as the rain driven away by the eddies must fall. somewhere, it will fall in increased quantities in irregular por- tions elsewhere, and this will double the difference of indication of guages at no great distance from each other. I am, Sir, your obedient servant, Ricuarp Davenport. Articxe VIII. On the Machine for measuring a Ship's Way by the Log Line. (To the Editor of the Annals of Philosophy.) MY DEAR SIR, | Tue enclosed communication I received from a gentleman of great respectability in Denmark. You will oblige me by insert- ing it inthe Annals of Philosophy. Very truly yours, . FoRCHHAMMER. —— ae Nothing is more probable than that two different persons may have conceived similar ideas on any particular subject; and when the inventions to which they give rise prove of essential utility, it Me but just that each should enjoy the honour that really is due to him. It is stated in the Journal of Science and Arts, edited at the Royal Institution of Great Britain (vol. ii. p. 90), that Mr. New- man has claimed to be the first inventor of a machine for measur- ing a ship’s way by the log line. This is stated to .be effected by means of a sort of watch which is to serve on board of ships in lieu of the usual sand glasses of one-quarter, one-half, or one whole minute. Mr. Newman’s description of his machine is as follows : “The quarter: and half minute glasses in general used for measuring a ship’s way have always been found very irregular. This irregularity arises from various causes, and particularly the state of the atmosphere at different times, and in various lati- tudes ; and even when they are new, it is scarcely possible to find two that will run out in the same time. New Series, vou. 1. H 144 Machine for measuring a Ship’s Way by the Log Line. [Frs. “« As the log line is in general use for measuring a ship’s way,’ it is evident that so inadequate a method of ascertaining the por- tion of time required must introduce many errors into the esti- mate made of the velocity and progress of the vessel; and a small, simple, and correct machine that can be depended upon for this purpose appears to be a very desirable improvement. “A bbe machine which I have invented, and which has had the decided approbation of many naval officers, appears to pos- sess every requisite for the purpose to which it is intended to be applied, It is enclosed in around brass box, three inches and a halfin diameter, and one and a half in depth. It has a dial, the circumference of which is divided into 60 parts. In the centre is an index, which is carried round by the machine once in 60”, or one minute. At the 15th, 30th, 45th, and 60th second, are holes made in the dial through which pins are pushed up or down by small buttons on the outside. The dial is covered in by a strong glass. “When the machine is used, being wound up, the index is to be retained at 60” by putting the pin up at that division. If then 15” are to be counted, the pin at 15” is to be put up, and the moment the log is delivered, that at 60” depressed ; the index immediately advances, and continues in motion until stopped at 15”. If 30”, or 45”, or 60”, are to be told, the pin belonging to the number required is to be put up, and the time told as before. “The beats of the machine can be heard at a considerable distance, and the moment at which it stops so readily distin- Sg that it may be used as well in a ait night as during ay, or by a light; and as it is perfectly accurate, very strong and very portable, it seems well adapted to supply the place of cae mcorrect minute glasses at present in use aboard on all ships.” think it, however, a duty incumbent on me to observe, that Rear-Admiral Lowenorn (a gentleman who as a hydrographer, in his capacity as Chief Director of the Royal Marine Chart Archives, has been of essential service to mariners ; and besides ‘this, has caused great number of lighthouses to be erected upon the Danish coast, &c. &c.) had already conceived this very idea several yedrs before, and was the immediate cause of the con- struction of a watch by an artist, by the name of Sparrevogn, who in the year 1804 constructed a portable log watch in the form of a common watch, which the person employed in logging may conveniently carry about his neck, suspended by a ribbon, or in any other manner. In the very moment, the first mark of the log line has run out of the man’s hand, he needs only to press upon a spring of the watch, which directly sets it going, and the index shows exactly the full seconds. "When the index of the watch points on to the 14th second (whichserves to denote one-quarter of a minute), this watch strikes a bell loudly in the 1821.] Action of Crystallized Bodies on Homogeneous Light. t15 inside, so that the person who is logging may directly, and in the very same moment, stop the line and count the knots; the watch meanwhile continues to go, and the index indicates the seconds until the 28th second (for this division is adopted here for the computation of our log), when the watch again gives a loud stroke, and the man at that very moment stops the line, in case he has let the log run to that moment which is used when the ship runs at a moderate rate; the watch is now run down, and stops at once. It is not wound up in any other manner: this is effected by the pressure upon the spring by which it repeatedly may be set going. The contrivance appears to be somewhat superior to that described by Mr. Newman. Mr. Sparrovogn (the above-men- tioned Danish watch-maker, who is now dead) made several of these log-watches. The Danish Board of Admiralty rewarded Mr. Sparrevogn with a proper remuneration, and Admiral Lowenorn laid before the Royal Society of Sciences at Copenhagen (of which he is a Fellow) a drawing of the construction of this watch, together with an explanatory description of it, which met the approbation of the Society. | ARTICLE IX. On the Action of Crystallized Bodies on Homogeneous Light, and on the Causes of the Deviation from Newton’s Scale in the Tints which many of them develope on Exposure to a polarised Ray. By J. F. W. Herschel, Esq. FRS. Lond. and Edin.* Since the period of the brilliant discovery of Malus of the polarisation of light by reflection, the investigation of the gene- ral laws which regulate the action of crystallized bodies on light has advanced with a rapidity truly astonishing, and the labours of an Arago, a Brewster, and a Biot, have already gone far towards completing the edifice of which that distinguished phi- losopher laid the foundation. When Malus wrote, the list of doubly refracting crystals was small, and the most remarkable among them possessing only one axis of double refraction,. it seems to have been for some time, tacitly at least, presumed that the law discovered by Huygens, and since re-established in the most rigorous manner for that one,} might hold good in all. * Read before the Royal Society of London, Dec. 23, 1819- + The author of the article on Polarisation, in the 6d number of the Edinburgh Review, just published, is guilty of a most unpardonable mistake, in asserting (p. 188), as deducible from Dr. Brewster’s experiments, that the Huygenian law is incorrect, for carbonate of lime. Dr. Brewster’s general formule for crystals with two axes resolve ‘themselves into the Huygenian law when the axes coincide, of which case it is only an ‘extension. That excellent philosopher, if I understand English, in the paragraph which gave rise to this strangeassertion, only means to declare his opinion that it Temains undemonstrated. ae ; H 2 116 Mr. Herschel on the Action of [Fes. ‘Thediscovery, by Dr. Brewster, of crystals possessing two axes. of double refrection, or two directions in which a ray may pene- ‘trate their substance without separation into distinct pencils, has proved the fallacy of any such generalization, and rendered it necessary to enter on a far more extensive scale of investigation. There are two methods which may be pursued in observations on double refraction and polarisation, the one direct, the other indirect. The former turns on immediate observations of the angular deviation of the extraordinary pencil, and is, of course, “only applicable when the forces which act exclusively on the rays composing it are sufficiently intense to cause a sensible separa- tion of the two pencils. ‘There exist, however, a midtitude of crystals in which the force of double refraction is so feeble as to ‘produce scarcely any, or at most a very inconsiderable deviation of the extraordinary ray, and in which, consequently, the laws of double refraction could neither be investigated nor verified, without having recourse to some artificial means of magnifying the quantity to be observed ; a thing easy enough in theory, but requiring, in practice, the greatest nicety on the part of the observer, and in many cases altogether impracticable, from the physical constitution of the crystals themselves. The indirect method depends on the discovery of Arago, scarcely inferior in intrinsic importance to that of Malus, of the separation of a pola- rised ray into complimentary portions by the action ofa crystal- lized lamima. It was reserved, however, for the genius of M. Biot to trace this striking phenomenon to its ultimate causes, in the action of crystals on the differently coloured rays, and to develope, in a simple and elegant theory, the successive grada- tions by which the polarisation of a ray in its passage through a doubly refracting crystal is performed ; while, on the other hand, the splendid phenomena of the polarised rings, which we owe to Dr. Bpsvrathe! have established the counection of the tints so polarised with the force producing the deviation of the extraor- dinary pencil, and shown the legitimacy of conclusions respect- ing the inteusity of the latter, drawn from observations on the former. This indirect mode of observation, which consists in noticing the gradations of colour for different positions and thicknesses of the crystal, possesses three capital advantages. The first is its extreme sensibility, which enables us to detect the existence, and measure precisely the intensity of forces, far too feeble to roduce any measurable deviation of the extraordinary pencil. t, in fact, affords the rare combination of an almost indefinite enlargement of our scale of measurement, with a possibility of applying it precisely to the object measured, arising from the Alistinctness of all its parts. Another, no less precious, is the leading us by mere ocular inspection to the daws of very compli- cated phenomena, and enabling us to form, and mould, as it ‘Were, our analytical formule, not on a laborious, and sometimes 1821.] Crystallized Bodies on Homogeneous Light. pyr deceptive discussion of tabulated measures, but on the actual form of the curves themselves, which are loci of the functions under consideration. It is true, that a reference to tabulated measures is indispensable to give precision to such first approxi- mations ; but the power this mode of observation affords of copying our outline fresh from nature, and from the general impression of the phenomena, brought at once under our view, is an advantage not to be despised. Nor ought we, lastly, to omit, in our estimate of advantages, the means thus afforded us of subjecting the minutest fragments of a crystal to a scruty as severe as the most splendid specimen, and thus extending ovr researches to an infinitely greater variety of natural bodies than we could otherwise hope to examine. _ In order, however, to render observations on the tints deve- loped: by polarised light available, they must be comparable to each other; and it, therefore, becomes an object of the first importance to ascertain the existence, and discover the laws, of any causes which may operate to disturb their regularity. Ever since I first engaged in experimental inquiries on the polarisa- tion of light, I was struck by the very considerable deviation from the succession of colours in thin lamine, as observed by Newton, which many crystals exhibit when cut into plates per- pendicular to one of their axes. I at first attributed this to a want of perfect regularity in their structure, or to inequalities in their thickness, arising from my own inexpertness in grinding and polishing their surfaces; and it was not till habit had ren- dered me familiar with all the usual causes of deception, that, finding the same phenomena uniformly repeated in different and perfect specimens, my curiosity became excited to inquire into their cause, the more so as they now began to assume the form of a radical and unanswerable objection to the theory of M. Biot, above alluded to, which affords so perfect an explanation of the tints in crystals with one axis. These phenomena have not escaped the vigilance of Dr. Brewster. In his paper of 1818, he distinctly notices the fact of a deviation from Newton’s scale, in crystals with two axes, and promises a more detailed account of it, which, however, has not yet appeared. But the object of the present communication 1s not thereby anticipated, as in the only passage in that paper m which he expresses himself otherwise than obscurely on its cause, he appears to regard the deviated tints as analogous to those developed along the axis of. rock crystal and by certain liquids ; an analogy which, in the present state of our knowledge on that perplexing subject, it seems not easy to admit. Ina paper too, which has lately appeared, containing the interestin observations of the same excellent philosopher on the optica structure of the apophyllite, he remarks the very striking devia- tion of the colours of this crystal from Newton’s scale *‘ in the 118 Mr. Herschel on the Action of \, |[Pes. first orders” of its rings; and while/he remarks that such devia- tions are common enough, and indeed universal in crystals “ in which the rings are formed by the joint action of two axes,” seems to think this analogy close enough to authorize the sub- stitution of two rectangular axes of a negative character for the single positive axis actually observed, according to his own peculiar and ingenious views on this subject. 1 lost no time in endeavouring to procure a specimen of this mineral, and by the kindness of my friend, Sir Samuel Young (to whom.I owe more than one obligation of this nature) was favoured with one suffi- ciently transparent for optical examination. From my observa- tions on this body, I think I shall be able to demonstrate satisfac- torily that the phenomena of the apophyllite depend on a. rinciple distinct from that which produces the chief part of the viation of tints in most crystals with two axes. The course I propose to pursue is, first, to describe the phe- nomena themselves. I shall then show how these phenomena, complicated as they are in appearance, are all reducible to one — very simple and general fact; viz. that the axes of double refraction differ in their position in the same crystal for the dif- ferently coloured rays of the spectrum, being dispersed in one plane over an angle more or less considerable, according to the nature of the substance. In many bodies, the magnitude of this dispersion of the axes is comparatively trifling, while in some, not otherwise remarkable for a high ordinary or extraordinary dispersive power, it is enormous, and must render all computa- tion of the tints.in which it is not taken into consideration, com- ‘ete erroneous ; and indeed obliterating almost every trace of Remiontis scale of colour. We have here then a new ele- ment, which, for the future, must énter into all formule of double refraction pretending to rigour, and at the same time are pre- sented with another very striking instance of the inherent dis- tinction between the differently coloured molecules of light, which, since the time of Newton, every new step in optical science has tended to place in a stronger point of view. At the same time, by the easy and complete explanation this principle affords of all the more perplexing anomalies in the tints, the theory of alternate polarisation to which they were hitherto so pate le and formidable an objection, stands relieved from every: difficulty, and may now be received as fully adequate to the representation of all the phenomena of the polarised rings; and entitled to rank with the fits of easy transmission and reflection, as.a general and simple physical law. In fact, if we investigate by this theory a general analytical expression of the tint deve- loped for any position and thickness of the plate, taking this: élement into consideration, it will be found to include all the phenomena, as far as they can be computed; while the daw of dispersion remains unknown. “But we may go yet further. The 1821.] Crystallized Bodies on Homogeneous Light. | 449 nature of the formula furnishes an equation by which the actual quantity of the separation of the extreme red and violet axes may be deduced from observations of the tints of a very simple and accurate nature, being perfectly analogous in principle to the “ method of coincidences,” which has of late been applied with such success to the most delicate investigations in every department of physical science. The comparison of the results afforded by that equation with those deduced by direct observa- tion on homogeneous light; while it leaves nothing to desire in point of accuracy, leads to another important result, viz. that the roportionality of the minimum lengths of the periods performed by differently coloured molecules, in a doubly refracting crystal to the lengths of their fits of easy reflection and transmission, supported as it is by an induction of no ordinary extent and accuracy, is yet not universal, admitting a deviation to a ve large amount. Hence must of course arise a kind of secondary deviation in the scale of tints. ‘In crystals with two axes, how- ever, this is masked by the much more powerful effect of the separation of the coloured axes; yet even there, is not altoge- ther insensible in an extreme case. In the apophyllite, however, the agency of this secondary cause is placed m the fullest evi- dence. The application of our general formula to the anomalous tints of that body, while it proves incontestably the exact coinci- dence of the axes for all the coloured rays, points out at the same time a peculiarity in its action on the more refrangible | extremity of the spectrum, of a nature so singular, so entirely without example in all the multitude of natural and artificial bodies hitherto examined, as ta render me extremely desirous of prosecuting the research, with the aid of more perfect specimens and improved methods of observation. Having arrived at the general result of a dispersion of the axes by the sole consideration of the gradation of tints in plates of - various thicknesses, it becomes interesting to verify it by direct ‘and independent. observation. This 1 have accordingly done ; and the fortunate discovery of a substance in which it is of enormous magnitude, puts it in our power to render the fact sensible to the eye of the most unpractised observer, by an exceedingly simple experiment, to be described in its place. Il. Of the general Phenomena of Crystals which develope Tints _ deviating from Newton’s Scale, by Exposure to polarised Light. In describing the phenomena, I shall at present confine myself to the tints developed along the principal section of the crystal, which is supposed placed in an azimuth 45° with the plane of primitive polarisation. The observations. of the tints. in this position are most easily made, and least liable to error, and we shall.see presently that it would be superfluous as well as embar- — rassing to examine other situations, the law of the phenomena being completely deducible from this. In this series of observae 120 Mr. Herschel on the Action of [Fes. tions, then, we traverse the polarised rings (PI. IV.) fig 1,* in the | direction of their axis of symmetry A A’, passing through their poles P, P’, and centre O. Now if we subject to this examina- tion any one of the following substances : Sulphate of soda? Arragonite, Sulphate of baryta, Sugar, Se Nitrate of potash, _ Hyposulphite of strontia, it will be seen that the tints between the poles P P’ correspond to lower orders of colour than would result from assuming P, P’, as the origin of the scale, and agree much better with the assumption of certain points p, p’, without the poles, as their zero, or commencement of the scale. The poles themselves too instead of being absolutely black, are tinged with colour ; and the tints beyond them, instead of descending in the scale from the poles outwards, continue to rise till they reach their maxi- mum (which is a white, more or less brilliant, or an absolute _ black) at the points p, p’; after which they descend again to infinity. Not that in any case they coincide precisely with the scale of Newton, even with this correction, but, except in extreme cases, approximate to it within some moderate limit of error. If, on the other hand, we examine in the same manner one of the followmg bodies : Tartrate of soda and potash, Sulphate of magnesia, Borax, Topaz, Mica, it will be found that the imaginary points, p, p’ (which we shall call the virtual poles), from which the tints must be reckoned inwards and outwards, to produce the nearest possible agreement with Newton’s scale, lie between the poles P, P’. In all these crystals, as the thickness of the plate examined increases, the virtual poles p p’ recede from the actual ones P P’, at least in respect of the number of alternations of colour which intervene between them: in other words, the tint deve- oped in the poles, or along the apparent axes of the crystal, ‘descends in the scale of colour, as the thickness of the plate increases, and vice versa. In very small thicknesses, the tints approximate pretty closely to Newton’s scale, or wholly coincide with it, while in very great ones, the tint developed in the poles ' is the composite white of the extremity ofthe scale. The angu- lar distance; however, of the virtual poles from each other and from the axes, remains absolutely unchanged for all thicknesses; and this striking fact, which I have proved by numerous and yar gg experiments, was first suggested for examination as a result of theory, and would equally hold good, as will pre- sently be proved, for every conceivable law of double refraction. * The whole of the fi in thi not being referred to in the present the Plate will be given siliee, its chi vehelae ofthe paper, in the next et sins 4 / \ Engraved for the Annals of Philosophy...Published by Baldwin Gradock & Joy, March 11821. _ pe pe ea ad . ae ’ a . me Ns Ne ee ' T Mia fr SA ph aging’. cnohagote ser Pee ‘ ‘ 4 ‘ , s tom pha Rey 1821.) Crystallized Bodies on Homogeneous Light. 121 -The substances, which I have examined most attentively, are ‘sulphate of baryta, nitre, mica, and Rochelle salt, and the sub- joined tables of tints developed for different inclinations in plates of the first and last of these, may serve as examples of the mode of action of the respective classes to which they belong on light, and will afford data for some calculations to follow. The first two columns contain the inclinations corresponding to similar tints of the incident ray on the moveable plate which carries the crystal, in the general apparatus imagined by M. Biot for obser- | vations of this kind. Were the plate cut ina direction precisely perpendicular to the optic axis (or line bisecting the angle between those of double refraction}, and adjusted with perfect accuracy on the instrumént, the excesses or defects of these angles above or below 90° would represent the angles of incidence. Neither of these conditions were, of course, exactly fulfilled. But it is obvious that the small errors’in these particulars (which were ascertained not to exceed 1° or 2°) must affect the computed angles of refraction on™both sides of the perpendicular with equal and opposite errors. ‘The same may be said of any error arising from a slight prismasticity of the plate, which, however, must have been extremely small, the plate having always been rendered parallel by the delicate test of tne spherometer, within a very few divisions.* Consequently, in calculating on these | data, the mean angle of refraction determined by the simultane- ous use of both observations (their semi-difference being taken for the angle of incidence), may be expected to differ from the truth by an extremely minute quantity. The third column con- tains the tint.developed in the ordinary pencil, and the fourth in the extraordinary. The last notices‘ the remarkable points in the system of rings to which the tints and angles in the other columns correspond. The positions of the poles were determined by interposing a red glass between the crystal examined and the reflector used to polarise the incident light. The glass used for this purpose was of that kind occasionally found in old church windows, and whose manufacture seems to be numbered among arts now forgotten. It transmits almost the whole of the red rays, and part of the orange; while it completely stops all the more refrangible colours. I have endeavoured in vain to procure specimen, whose limits of transmission are more confined. Such are said to exist, though very rare ; and in the absence of such, the indications of that employed may be taken to corres- pond to the mean red rays. * Each equal to the 23809th part of an inch. 122 Mr. Herschel on the Action of [Fas. Tase 1.—Sulphate of Baryta. Thickness of Plate =0°11964én. on mreeeere | Ordinary pencil. Extraordinary. © Remarks, &c. 43°55! /134°37’ Pink. ......... j sise'eis Wie oe e blue green ......|Tints beyond 45 0 |133 42 Bluish green............ Pin # the poles. 46 0 |132 45 [Rich pink .... Reautifil green 182. 0 |Whitish..... soeqesoce ye Dull purple 46 58 |131 37 Splendid green,.......... Rich crimson BSL OBR oie 6 ong eb wren oo lne bine Yellow 47 53 |130 45 |Crimson............+... Fine green . with Yellow, inclining to orange|Blue_ | Ww. eeeeweseeeerene Purple 48 51 {129 30 |Blue green p esbie'e ad aad’ sai Rich crimson BN v.05 thd a ntetonced bes Orange 128 58 BE codebsavvdd watts. Pale yellow Rich crimson red. ........ Pale green or greenish white Fine orange. ........+.+. Light blue Pale orange yellow...... .|\Dark blue SO BS {27 45 | White. ... ccc. ceeee -Sombre and very narrow purple Bluish white ............/Scarlet or fiery red Light blue... .....++.00 Orange Sombre greenish blue.....|Ruddy white, or very pale ; orange 52 0 {126 50 sin and very sombre BB. ©, «eons dipbmenene White Sombre and narrow pinkish erect Adil se White e violet or eR: sd ome Greenish white White... ows e cv ccowcecs's Dirty bluish green BS 1 [ISS AT | White. 0. ec cec cece .|Narrow and very sombre} violet purple...... . ++++|Virtual poles 125 30 | White slightly yellowish . .| Violet P, p',or points 125 0 |Pale and dirty olive green.|Violet white of coincidence Very narrow violet. ...... White 54 8 /124 30 mee very sombre and nar- dityaidie sya cmbaaig ...|White slightly yellowish ‘Light DUNC » s0.00% «0.0.06 9:99 Pale yellow Bluish or greenish white . ./Indifferent purplish pink 55 25 |123 30 | Yellowish white.......... Sombre and narrow purple Light yellow ........++6. Dark blue Dull orange pink. ........|Pale greenish blue 56 33 |122 15 et purple .......... Pale yellow. green Sewer veces eesere Yellow 57 30 Recto «a eeeeeeeess-|Fine pink verging to crimson. ST 50 |121 0 |Pale yellow. ..........-- Purple 58 15 {120 15 ake rep mg ee rape psig Greenish blue........ ..../The polesPP” ch pink . 2.6. sccecsees Bluish green Tints between 59 12 |119 35 Pale purples. si ds sisiasesiss Greenish white the axes. Blue green ......+++++- . -|Crimson GO.45 [118 20 |White.........sccceeees Very pale purple 117 40 |Pink. ....... se bahemae Blue green 62 0117 5 |Pale purple. ...........-|Whitish 62 58 |116 25 |Greenish blue.......++-. Pink 63 25 |115 35 |White..........00. é.--.| Dull e 64 28 |114 47 |Pink....... dp e's sukuk geoub 65 40 {113 20 er blue. ....eeeeee- Pink 67 30 |111 30 « seeeeeee-| Pale greenish blue 69 15/110 0 Pale gresnish blue........ Pale pink 1821.] Crystallized Bodies on Homogeneous Light. 123 - In this plate, the virtual poles correspond very nearly to the second minimum of the extraordinary pencil beyond the poles PP’, The same plate was now reduced by grinding to the thickness 0°08816 inch. In this' operation, care was taken to grind away the side of the plate most distant from the eye only, leaving the other perfectly untouched and unimpaired. in its polish. The: plate being reduced to exact parallelism by the spherometer was again examined, the same side still remaining next the eye. By this arrangement, the same angles of emer- gence from the posterior surface correspond rigorously to the same directions of the ray in the interior of the crystal, with respect to the axes of its molecules ; and thus we avoid com- pletely any errors which might arise from using plates cut at different angles, it being almost impossible to cut two plates precisely alike in this respect. Taste Il.—Sulphate of Baryta. Thickness = 008816 in. onic ave Ordinary pencil. Extraordinary. Rematks, &c. 58° 0/,120° 0'|Pink, verging to orange RIO 0 os Sani ¢ wale ans Blue, somewhat greenish ..|Poles for the VOT oad eta co-ay' s:sn0e eels Yellow, verging toorange the poles. Riarke. BIUG os.s a0 ced cee pers Bright yellow ; 55 57 {122 15 |Sombre purple........... Yellow white Very indifferent sombre PINK, «+9 anne A titappeiae Bluish white d Pale. yellow acc.ccc0nn esas Dark indigo blue SO PURE 0 TIRE so oii ones seks siccees Sombre violet Very pale violet white . ...|Dusky greenish yellow 52 57 {125 33 |Very sombre violet, almost TUMOR cade dads ogee Pure brilliant white. ......| Virtual poles Sombre and dirty olive j BQO. coe kas aiea eg ..|White, rather ruddy Very. pale blue ..2<«..0.. Orange white - |White......+...++...++.-;Sombre orange or brick red SPS 1ST O | White. ii ds Narrow purple Orange white. ....... ....| Blue 4 Bright orange. .......... Pale blue Bright scarlet. ......... -|Bluish white Narrow crimson. ...... . .|White 504: O:98. 30 (Purple... cccscsesscee: White BG <0 o cavte nv cseeec +] MELOW Bluish white....... .-...|Rich crimson 48 40 {130 0 Yellowish or greenish white| Purple Orange yellow ........+- Bright blue AT 35 }131 10 {Rich crimson...........- Green 430 1481 28 i Purple. .....secccsesce- Good yellow Bright blue... .....eeees. Pink yellow 46 1 |132 33 |Good green. ........+.+- Rich pink or crimson 45 3 |133 45 |Rich pink........... .---|Splendid green 44 33 |134 30 |Greenish purple...... .+.-|Pinkish white 43 35 |135 15 |Good green, but pale. ....|/Fine pink 42 23 {136 30 |Pinkred..........-.....|Greenish blue 40 55 {138 0 | Pale bluish green........|Pale pink 39 30 1139 50 IPale pink.............../Very pale greenish blue ~ Mr. Herschel on the Action of [Fre. In this plate the virtual poles correspond to the second maxi- mum of the extraordinary pencil. It is needless to detail the tints between the poles. The same plate once more reduced with the same precaution to leave the posterior surface un- touched, developed the following series of colours beyond the poles. TABLE I11.—Sulphate of Baryta. Thickness = 0:05758 in. gsi cma Ordinary pencil. Extraordinary. Remarks, &c. 60° 57’ |122°50’ |Fine yellow ............./ Indigo. ...... bo bo gM Poles, for the 60 20 |123 27 |Pale yellow. ............ Purple mean red rays. White, inclining to yellow.| Dull crimson red.......... Tints beyond Bluish white ............ Dull orange _ |te poles Indigo.......... bie ed WN Yellow 57 55 |126 3 |Sombre purple. .......... White 57 50 |126 7 |Sombre reddish violet ....| White 57 20 |126 33 | Dirty violet yellow. ...... White 127 30 |Pale yellow. ...........- Violet white 55 40 128 2 Whites 66.58. e ey. ooh Sombre violet 55 33 |128 20 {Pure brilliant white...... papel EE er -»..| Virtual poles 128 30'| White oo. 50. senses ..--|Sombre dirty green Pale orange. <2 ..6..00- Pale dirty bluish green 53 40 |130 10 |Sombre orange or brick red) White 53 27 {1380 30 |Sombre and narrow purple) White ORIG Ese vce chase .eeee--|Ruddy white Pale Dhue «0450.05.00 rae»: Orange Bluish white ............ Orange red 152 20 | White... 2.5200 esveee -| Narrow crimson 51 3 |132 40 Purple, &c. &c. Pale yellow, &c. &c. .... Here the virtual poles p, p’ correspond precisely to the first minimum of the extraordinary pencil. In a plate of Rochelle salt, cut nearly, but not quite perpendi- cular to the optic axis, and whose thickness was 0°194425 in. the rings beyond the poles were almost entirely obliterated, while those between them exhibited the following singular suc- cession of colours, which will show to what an extent the devia- tion from Newton’s scale is carried in this substance. 1821.] Crystallized Bodies on Homogeneous Light. 125 Tasie 1V.—Rochelle Salt, perpendicular to the Optic Axis. Thickness = 0: 194425 in. n ‘ N * Comesnagots Ordinary pencil. Extraordinary. Remarks, &c. 201°301330°10'|White. ..........-0..4..| White. ....... cc... ..|Poles PP’ for 207 10 Exceeding pale blue.... .|Exceeding pale pink red rays 209 0 ‘Exceeding pale pink ...., .|Exceeding pale blue 210 30 Very pale blue .......... Very pale pink 212 30 Very pale pink ......... Very pale blue 213 20 Very pale blue......... ..|Very pale pink 215 25 Pale pinks iads coc ceis e')s Pale blue green 216 40} Cee Pale yellow pink 218 0 PAIK tin odd adn asso hbWes ¥s Blue green 219 29 Pale lites. eves: ....|Pale yellow pink 220 58 |) SOPOT UTE SLCr es Greenish blue Ab EEE eee Very pale purple 222 30 BMGs. <\s0.-0.05 5 6960000} Clow pink 293 45/309 30 |Yellowish pink.......... Greenish blue 224 50/308 15 Pale greenish blue....... Yellowish pink Blue... sia sawibiades Pale pinkish yellow 226 10/307 0 ‘Pale pink. .........5.... Pale greenish blue 306 10 \Pale yellow. ............. Dark blue White «sedis wacwienus Pale purple 297 25 Bluish or greenish white. .|Very pale violet pink 228 30 Bhne.. . cp iig. Naisy sue wet Very pale yellow Violet almost imperceptible} White 229 3/304 10 |Pure white.............. Pave -white.......cpilneiciges ss Virtual poles Exceeding pale yellow.. .{A little violet p> p' 229 50 Pale yellows. si... ssives: Very narrow dark blue |Very pale tawny orange..|Blue, sombre, and pale 231 20/302 20 Fine purplish crimson ....|Pale yellow green Very pale purple ........ White 232 25 Very pale green ......... Fine crimson White .... .aiklw. elev ex Pale purple 234 . 0/299 20 Splendid crimson. ........ Very pale green Pale purple, ..°. 50.0000: White 235 40 Very pale green....... ..|Rich crimson WEDUEOs ssa sce a iced RENT Pale purple 236 23/296 15 Rich crimson............ Very pale green Pale porple 3:1. .isdilings'0i White 238 50 /294°35 Pale blue green.......... Good pink, almost crimson WD WDD: 5seis oon 90 Kwa oe Very pale purple 240 12/292 55 Pink, rather pale ........ Pale greenish blue White. .. 10608 cutoumends White 242 10|291 30 Pale blue. ...... siya . |Pale yellowish pink 243 40/289 50 |Pale pink yellow.........|Pale blue 245 10/287 45/|Very pale blue .......... Very pale yellow (246 50/286 45 |Very pale yellow green. ..|Very pale lilac blue 248 25|284 55 /Pale lilac....... db siewhenie Yellow green NG va vgs ccs oebion ....| White 250 40/232 30 Fine yellow green........ Fine lilac WRI. cc css0e Perret White SOR ST IPED AD i Ldlac. .. 6500.0 ccesieye ces Fine yellow green White... v0ae5 csadeye ..| White 256 5/277 25 Fine yellow green........ Fine lilac White 0... cececithituns White 259 20/274 40/|Pale lilac......... saves Fine yellow green 261 40/271 40|White.. ........ bwwerere} White 266 40/266 40 Green yellow........04:. Pale lilac....-.. s»s:«0. seoee [The middle tint 126 Mr. Herschel on the Action of [Fes. In order, however, to avoid the effect of the dispersive power, which, at such considerable obliquities, would render the obser- vations liable to some uncertainty, [ cut another plate in such a manner that the perpendicular to its surfaee, instead of coincid- ing nearly with the optic axis, was directed very nearly to one o. the virtual poles. Its thickness was then gradually reduced in the manner above described for sulphate of baryta, though, owing to the nature of the body, it was found impcssible to avoid the necessity of re-polishing the posterior surface at each operation; but as this was done with all possible care, only a very slight error can have arisen from this cause. Tasre V.— Rochelle Salt. Thickness = 0°11518 in. - erg Ordinary pencil. Extraordinary. Remarks, &c. 277° 8! | Very pale pink..........|/Very pale bluish green. .......-.-|Pole P for jmean red rays BD AS Ui as gris bi Scie o cc se on eVURUITON ave ciheterebeinee see veeceeess»|Perpendicu- 261 0 |White, tinged with orange) Very fine intense indigo lar incidence 260 25 | Yellowish or greenish white) Purple, rather sombre 259 45 | Very pale greenish blue . .| Indifferent purplish pink DING vaberewrnronps Yellowish pink white 258 50 |Fine deep indigo ........ White inclining to orange 258 30 | Violet purple...........- Yellowish white 257 35 | White, a little tinged with Vgolet, Ved. UiGeiniot ...-|White, not very brilliant. ......../The virtual Yellowish white .. ...... Pale violet blue Pp 256 30 |Pale yellow.......... ...{Sombre indigo, inclining to violet, narrow, and well defined Pale pink yellow......... Sombre violet white 255 10 |Pinkish purple.......... Very pale greenish yellow 254 30 |Rich sombre purple, some-' what flery ...../b tess White, tinged with greenish yellow Pale green ...... o vattcts ine crimson ; 252 30 |Extremely pale green ... .|The richest deep damask crimson WONG. wins nisic'v de shh obi Livid imperfect. purple 250 27 |The richest damask crimson| Fine pale green Livid imperfect purple. . . ./| White 248 5 ae bluish green.... ... mae crimson 245 45 | Pink, approaching to red. . e blue green 243 30 [Sky * ie Pe re .....(Light pink, strongly inclining to| orange red 240 25 | Pink orange ............ Pale greenish blue Sky blue, inclining to lilac .|Fine yellow 237 30 |Pale bluish green........|Fine pink, a little purple 237 0 |Splendid yellow green lat 234 20 |Rich lilac ............08. Splendid green 230 10 |Splendid green .......... Rich lilac White. ..6. 0. ea eth 80% . .| White 225 45 |Lilacblue. ....... eevees iSplendid yellow green : Witte. 5. . sacnsevcused . -| White : 220 40 Splendid green yellow .,. .| Pale lilac blue WMS... 20006 hematin es A 211 40 |Pale lilac. ........... Fe -emgayaidaae 197 30 [Fine yellow green....... .|Fine li 1821] Here the virtual Crystallized Bodies on Homogeneous Light. 127 ole was coincident with the fifth maximum . (or thereabouts) of the extraordinary ray from the pole P; the succession of tints, however, unless close to the virtual pole, is omitted, in order to shorten the table. Taste VI.—Rochelle Sali. Thickness = 0:08557 in. Ine Ordinary pencil. Extraordinary. Remarks, &c. 262° 0’ |Good light pink. ...... . |Light blue green ........ bas ceed [Pole RP) for mean red BTS 0 |... cere eeen cece Pes ‘So rece eseseees ote tec ee seen . -| Perpendicu- Very pale yellow green. .. .| Bluish purple lar incidence 278 20 278 55 280 O Very pale yellow green... Very pale bluish green... Indigo....... e@eenaaeneere 281 30 |White....... Very pale greenish yellow Pale greenish yellow Pale pinkish yellow ...... Pale pink..... ethadbie fe Crimson ....+.- P Rich fiery damask crimson Livid imperfect purple,... Fine light green. ......... Very pale green. .......- Good crimson..... Crimson, almost scarlet, &c. 282 35 eaeeee 285 15 285 45 287 50 288 45 eoeenerce 291 40 Violet ..|Very pale yellow .| Yellow green Very light pink, or pinkish white | Very pale yellow, almost white White, perfectly equal and alike... Pale lilac Sombre lilac purple Dull and impure blue Pale yellow green Very pale yellow green Very pale pink yellow Fine pink. Splendid crimson. Blue green Pale blue green, &c. Virtual pole __ In this plate the virtual pole fell about half way between the fourth maximum and the fifth minimum of the extraordinary ray from the app more ground down, it gave as follows: arent pole P for the mean red rays. When once Tan ue VU.— Rochelle Salt.’ Phsekness: 006487 tn. Inclina- ‘aan Ordinary pencil. Extraordinary. Remarks, &c. 262° 25! |Fine pink....... veec'es ad Indifferent purple ........ Indifferent lilac pink ..... Pale yellow, inclining to a ee POTENT CELLO K Fine pale yellow ........ Yellowish white, or pale POG s cae ance connects White ..... eeecsene eareee 277 20 218 25 280 50 282 «0 Very pale blue ........4. Sombre indigo........... Very pale biue........... Yellow green........ ohele Pale yellow green...... os Greenish white,.......... PURTORL DLS win iasin'g a't.s ¢.0.4 Very pale pink...... bid de's Deep fiery crimson ....... Very dull purple (greenish) OME <4 ons Perrrreriry s Very pale blue, &c. ...... 284 50 288 25 293 33 294 50 Fine light blue green......... Yellowish white . Very pale greenish yellow |Blue, rather pale........ eaceseces Beautiful sobre indigo Violet White, with an almost imperceptible tinge between yellow and violet. . Yellow white Pale yellow white Extremely pale pink white Lilac pink Deep lilac pink Rich, but sombre purplish crimson Dull purple Good blue green White White Pink yellow ‘Rich orange, bordering on red, &c. .| Pole P for mean red rays Perpendicu- lar incidence Virtual pole 128 Mr, Herschel on the Action of _ [Fes. III. On the Causes of these Phenomena. The developement of colour along the axis of double refrac- tion is at first sight an og oun to the producticn of the seconda tints along the axis of rock crystal, discovered by M. Arago, and recently explained by M. Biot, in a masterly memoir communi- cated to the Academy of Sciences, on the hypothesis of a force inherent in its molecules independent of their state of aggrega- tion, by which they communicate a rotation in an ms direction to the axes of polarisation of the luminous rays. And this analogy is partially supported by the fact, that the tint deve- loped along the axis descends in the scale of colour as the thickness increases. . | _ A more scrupulous examination, however, will show, that its origin must not be sought in any cause of this nature, for (not to ‘mention the impossibility of explaining the phenomena of the virtual poles by this hypothesis) if we place the principal section of the crystal in the azimuth zero, the extraordinary image will be found to vanish completely for every angle of incidence, and whatever be the thickness of the plate. i may add too that I- have in my possession a crystal of quartz, which exhibits with tolerable distinctness in some parts the phenomena of two axes, _ and the appearances produced by the interference of the secon- dary tints in this specimen; while they agree completely with M. Biot’s explanation, differ entirely from those which form the subject of this paper. Neither are the phenomena above described explicable on any supposition of a peculiar action of the crystal on the ‘differently coloured rays, analogous to its ordinary or extraordinary disper- sive power, by which the periods of alternate polarisation of the molecules of some colours, should be lengthened, and of others contracted, so as to disturb that exact proportionality to their periods of easy reflection.and transmission, which M. Biot has proved to be a necessary condition for the production of the tints of Newton’s scale. It is true, such laws of action may be imagined, and J shall presently show must really exist; in all crystals probably to a small extent, but in two instances at least, to a surprising degree. But this alone will availus nothing. To show this, and at the same time obtain a general analytical expression for the tint developed at’ any inclination, and for every hypothesis of the action of the crystal on the differently coloured molecules, let us denote by c the length of a complete period of easy transmission and reflection, or the extent of one pulse, on the undulatory hypothesis in vacuo, and at a perpendi- cular incidence for any homogeneous ray, and let C denote its colour and BrORBHGHE intensity, or illuminating power, in the prismatic spectrum. Then will the formula representing a beam of white light intromitted into the crystal, be pee e C+ C+ C” + &e. from one end of the spectrum. to the other. 1821.] Crystallized Bodies on Homogeneous Light. 129 Let n be the number of periods (each consisting of a double alternation) and parts of a period performed by the elementary pencil C, in a ek through the medium: then, according to the theory of M. Biot, when 7 is 0, 1, 2, 3, &c. ad inf. the pencil. will wholly pass into the ordinary image ; but when the values. of n are 1, 3,4, &c. it will wholly * be thrown into the extraor-— dinary one, and in the intermediate states of n, partly into one,, and partly into the other. These conditions are satisfied if we represent by sin.? (x) the intensity of the ray in the ordina image, taking unity for its original intensity; and it will, I believe, be found, that the gradation of intensity given by this formula for the intermediate values of 7, will agree sufficiently with the judgment of the eye to warrant its adoption.+ ‘The part of the elementary pencil,C then, which enters into the extraor- dinary image, will be C. sin.?(n 7). Let us denote by 8 §C. sin.* (n 7)? the aggregate of all such elements from one extremity of the spectrum to the other, or take ‘ S§C. sin? (n 7)} = C. sin2 (nm) + C’. sin.? (n! m) + &e. Then will this expression represent the tint developed in the extraordinary image, and, consequently, S {C. cos.? (n =)} that in the ordinary one. Now, n, the number of periods performed depends, first, on the nature of the ray, or on-c; secondly, on the intrinsic ener of the action of the medium on that ray ; and thirdly, on the direction of its course, the thickness of the plate, and whatever other cause or limit of periodicity may happen to prevail. Hence we may taken = M x k, k being a function ofc, de- pendent only on the nature of the body through which the ray C passes, and M being a certain multiplier whose form we shall consider presently. This substitution made, the expression for the tint becomes 8S §C. sin.*(M k..7)} In the theory of the Newtonian colours of thin plates and the olarised rings in crystals with one axis, the multiplier M is independent on c, varying only with the direction of the ray and the thickness of the plate. It is, therefore, the same for all the coloured rays, and the tint, for any value of M, will be * The amplitude, or total extent, of each oscillation of the plane of polarisation is here supposed 90°, in which case the contrast of colour in the two pencils is at its maxi- mum. ‘This is the case in the situation we are considering, but in general the intensity of the extraordinary ray, instead of being represented by sin.? » z, will have an addi- tional factor, a function of the azimuth A of the principal section of the crystallized. plate and the position of the refracted ray, and which becomes unity when A = 45°, and the plane of incidence is that of the principal section... It is on this factor that. the gradation of brightness in the isochromatic lines, and the black cross or hyperbolic. branches which intersect them, depend. But it is not my intention at present to enter on this part of the subject, for reasons to be explained further on. + No part of our subsequent reasoning depends on the form of this function. It is sufficient to know that it must be a periodical, and even function of x. It is only in the computation of numerical values that it is necessary to make any more precise as~ sumption. : New Series, vou. 1. I 130 4 My, Herschel on the Action of [Fes, C. sin? (M kx) + C’, sin. (M Xk’) + &e, (a) ~ Now, suppose M to begin from zero, and to pass, by a yaria- tion either in the direction of the ray or thickness of the medium, ‘er both, through all gradations of value, to infinity, or to its aximum, if not susceptible of infinite increase : then we see that or every value of M a certain peculiar tint will arise, and that, soeiied M commence at zero and continue increasing, the same succession of tints will invariably be developed in the same order, Consequently, if we fix upon any two tints in this scale of colour, or any two values of M, the same succession and the same num- ber of alternations of colour must invariably intervene between them, however we pass from one to the other. _ In acrystal with two or more axes, the value of M for any ray C must of course be zero in the direction of the axis, and, there- fore, if the same supposition of the independence of M on c he made, the same conclusions should follow ; namely, first, that the extraordinary ray must always vanish in the née, whatever be the thickness of the plate ; and, secondly, that the same suc- cession and number of alternations of colour should intervene between the pole and any assigned unequivocal tint, such as black, or the pure brilliant green of the third order of Newton’s scale. Both these conclusions are totally at variance with the facts above detailed, as to the developement of colour in the poles, and the situation in the order of the rings of what we have called the virtual poles. Hence we are necessitated either to give up the theory of alternate polarisation altogether, or to admit the dependence of the multiplier M on ¢, or on the nature of the ray. Let us see to what this will lead us. According to the theory of the polarised rings, if extended to erystals ie two axes, the number of periods performed in a given space (= 1) by a molecule of a given colour, transmitted in a direction making angles 6, #, with the axes, can only be a function of the form’, y (4, 6’), k depending on the intensity of the polarising force; or, as before, being a function of c, the nature of the ray, and of the intrinsic energy of the molecules of the erystal. Now.if we call ¢ the thickness of the plate, and ¢ the angle of refraction, —— is the length of the path described, cos. and, therefore, we must haye for the number of periods . kt i n=—.¥(6,¥); Cos. P so-that the value of M must be eae which must be a func- tion of c. Now t is obviously epee of it; and if we neg- lect, at, present the very trifling effect at moderate incidences. of the ordinary dispersive powers of the media examined,* isso also. * It is easy to see, that in the two, classes of crystals above described, the effects of, the dispersive powers will be opposite to each other, in one opposing, and in the-other: +* 1821.J) . Crystallized. Bodies on Homogeneous Light. > 13k. It.is, therefore, in. the form.of the function J (4, 4’) that we must look ‘for the cause of the phenomena, and since, we have # = 6+ 2a, 2.a.being the angle between the axes (because the observations. are made in the principal section) we see that + (6, 4 + 2a) must involve c, and consequently, @ being arbi- trary, and independent, a must, be a function of c.. In order then to-render the theory of, alternations applicable, we must admit the angle between the axes of double refraction to-differ in the same crystal, for the. differently coloured rays. We must now show that this supposition is, sufficient to represent. the pheno- mena correctly, _ The symmetry. of the rings and total evanescence of colour in. the principal. section at an azimuth zero, requires that the axes of all.the different colours shall be symmetrically arranged, on either side of a fixed line (which may be called. the optic axis). in this plane, or in one perpendicular to it... At present. we need, only consider the former case. Let a represent. the angular dis-. tance of the axis for any one standard species of ray C. (the extreme red, for instance). from this line, a + éa, the same distance for.any other ray.. Then the distance of the transmitted. ray C, from the axes of rays of that, colour-being 4, 6’, the corre-. sponding distances from, thew respective axes for rays of any. other colour C’ emerging in the same direction will be 6 — 8 a@. + 0?¢and’+28a+.d¢, %¢ being the difference (= 9’ — 9). of the. angles of refraction, corresponding to the same incidence, for the colours C, C’..The positive, values of @ here reckon. outwards from the pole ; 3 a is negative for crystals of the second. class, and 2 ¢-is negative or positive according as C, or C’ is the. less refrangible colour. : Let.us for a, moment consider rays of only these two. colours., The. portion of the extraordinary pencil due to. them will be 3 tht kt ym tt : kit 7 C. sin.® (= + 0,0). 2) + C’. sine (5 P@- Fa +8, Vv + ba 4%). 2). | - The-rays of these colours of the same order in their respective: series of rings, will, therefore, coincide, and that in the proper degree of proportional intensity for the production of a white image, provided we. suppose : k k' | wet GM = Se ¥C— 244 te 0+3a42¢);, & which, since k, k’, a, 8 a, are constant elements, ¢, o’ determi- nate functions of 6, and # = § + 2a, suffices to determine & \— If we suppose C and C’ to represent the extreme red and violet rays, it is evident that the coincidence of the extraordi- conspiring with the causes which produce the deviation of tints. In the tables, Nos. V, VI, VI, where the virtual poles were observed almost at a perpendicular incidence, the influence of the dispersive power is quite insensible. © , 4 132 Action of Crystallized Bodies on Homogeneous Light. [Frs. ] nary pencils of the same order for these two extremes, will ensure’ that of the intermediate ones, at least very nearly. It would do 0 precisely, were the value of 8 a for any intermediate ray, such a function of k as would result from making 6 constant in the preceding equation, because the two laws, that of the dispersion of the axes, and that of the magnitude of the rings of different colours, would then act in exact opposition to each other throughout their whole extent. It is in fact a case precisely analogous to that of the compound achromatic prism, where, if the law of dispersion in the one medium were identical with that in the other, a perfectly colourless pencil would emerge, and when these laws differ, the coincidence of the red and violet , rays ensures an approximate coincidence of all the rest. Should" these laws, however, differ very considerably, an uncorrected colour will appear at the point so determined, and a nearer approximation will be obtained by uniting two of the more powerful intermediate rays, such as, for instance, the mean red» and the blue, or limit of the green and blue. ‘ | This then is the origin of the virtual poles or points beyond or between the axes where the tint rises to a white of the first order, more or less feeble, or even to an absolute black; and we may now see the reason why the tints, in reckoning from’ these points, approximate in a general way to the Newtonian scale. In fact, the periods of the more refrangible rays being performed more rapidly than those of the less, if we suppose the » coincidence above spoken of to take place at any point (the: minimum for instance) of the nth ring, the intervals between the nth and (nm + 1)th minimum will be greatest for the red, and» least for the violet, &c. Consequently, when the violet next disappears totally from the extraordinary pencil, there will remain yet a little of the red, less of the orange, and so on, and this differepec increasing at every succeeding minimum on either side, will produce a succession of colours approximating in a general way to Newton’s scale. This approximation will, how- ever, be much less close on the side of the virtual pole towards the nearest axis, because the disturbing influence of the separa- tion of the axes on the figure of the rings and the law of their successive intervals, is much more sensible than at a distance from the pole. This will be evident if we consider that in the interval between the extreme coloured axes, the tints will be regulated entirely by the law of their distribution. Now this is perfectly corroborated. by the succession of tints in the foregoing tables, as well as by numerous experiments made on other bodies. (To be continued.) 138 Meteorological Journal kept at New Malton. 1821.) §F-66 | L | 06 | SIT | 91 | se | 16 | 16 | 661 +8 | to] FT 1 93) se] 6E | BL | 2 fe 006-9F| 69T| 96-08) $8-G| $0-82| 06-08) LF9-62 ipieeae - Tenuu 18-T | 0 € | 9 6 L I I 6 6 6 0 L 8 I 96 | 66 GG) §06-6E! 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"SONIA “WOWUAHL §.XI8 ‘UA LANOUVEA “0681 "10349099 “fF “ATT Ag ‘X aATOMLUy “OCRT mag ay7 wa ‘aanysy.toX ‘Uo, many yn day sajsisayy Jonsoposoajapy 0 fo synsayy r ra + 434 Meteorological Journal kept at New Malton. | (Fxh. ANNUAL RESULTS. Barometer. eae: a ce big Inches. Highest au were Jan. 9. Wind, 1 i RARE Tail eee! 30°900 Lowest ditto. Oct. 17. Wind, Boresosissers ie ann ahs eaytte, 28°050 Range of the-mercury. .. 2... oo. eeis ee seo pel 2°850 Mean annual barometrical pressure... .. .. 6 6. see iea's “3 '29-647 Greatest range of the mercury in Jan. (in nine. doy) is ‘i “2660 Least ditto, ditto, in December. .. 2... osc ev eis ee 0-850 Mean annual range of ditto...... is Wo. deen Babh thoes 1505 eo described by ditto, ccevsees Careers i » 80-950 tal number of changes in the year ........4: ., 169: 000 Six’s Tisimbendter. Greatest observations, June 26 and27. Wind N ; and ee a ee ee Lak eee SSiebw sha :E2000° Least ditto, Jan. 1. Wind, W, ........ we re Fe! Range of the mercury in the thermometer........ +5 78-000 Mean annual temperature. ..... ee ee ee ee 46-900 Greatest range in June........ +5644. oars neo foi ode 45-000 Least ditto in November ...... ee ote ade dpieiharyc ol 25-000 Mean annual ditto. .......+se00- Tide tee LR oh 34-333 Winds ; Days. Notth aid: Ratt..~ o.3 as Agi... ety As > Eile, ote - 65:000 North-east and South-east. ...... ia 5 gicce-h Soke aes e's 5 . 66-000 South and West. ............. Te eS 93-000 South-west and North-west .........08-sceeeces «» 121-000 WMMNe? 0. $5 B S03 op he. wupeNehe a «Me aeae . 21-000 Rain, & Inches. Greatest quantity in May...... 0. cesses e eee e sees 4250 Least ditto in September .......0. 0... e eee ss oa ogee OOO Total amount forthe year. ...0......ceeeeeeeeee »« 29°430 HBL) Dr ir copay of War. wo Aerob KT Observattanssan Me’. Perkins’s Account a the Compressibility of ‘Water. By P.M. Roget, MD. FRS. &c. (To the Editor of the Annals of Philosophy.) 2? (DEAR: SER is Vs. Bernard-strect, Russel-sqnate, Jan. 25, 1821. “On reading the: account which Mr. Perkins has lately given inthe Philosophical Transactions,* of his very interesting expe fiments on the compressibility of water, from which he has -deduced a result differing widely from that of Mr. Canton ; and being desirous:of ascertaining the exact quantity by which they ‘@iffered, | was induced to calculate the degree of compression which was. produced by the piezometer in the first experiment, from the data furnished by Mr. Perkins, and was thus led to the ‘discovery of avery’ material error which he has committed in his computation. He states the compression affected by a pressure of 100 atmospheres to be ‘about one per cent ;” whereas the - 1 12-367 OF ® little less than one-half per cent. as may easily be verified by any one who will be at the trouble of going through the calculation. It is remarkable that this amended result agrees very nearly with that of Canton. ‘This will be best evinced by computing the heights of the modulus of elasticity of water, in the two cases, according to Dr. Young’s method. As deduced from Canton’s experiments, the height of the modulus is 750,000 feet; while - those of Mr. Perkins, when correctly computed, would show it to be 743,260 feet-—the difference being less than one-hundredth of the whole.. So near an agreement, in experiments conducted by different methods, is Way saisacioy, and bears the stronger testimony in favour of th curacy of those of Mr. Perkins, in as much as he was himself not aware of that agreement. It is much to be wished that this gentleman, to whom science and the arts are already much indebted, will persevere in the prose- cution of his interesting inquiry, by the aid of the ingenious ‘apparatus he has invented, and from which the discovery of many curious and important facts may be expected. : I am, dear Sir, most truly yours, P, M. Rocer. real amount of the ‘compression was, in fact, only * For 1820, Part II. p. 324. + Young’s Lectures on Natural Philosophy, i. 276. 136 New Substance in Ironstone. [Fep. : ArTICLE XII. Description of a new Substance found in Ironstone. By the Rev. J. J. Conybeare. (To the Editor of the Annals of Philosophy.) MY DEAR SIR, Bath Easton, Jan. 11, 1821. _ DuRING a visit to South Wales in the course of last summer, a substance, found in the ironstone of Mezthyr Tydfil, was put into my hands for examination. It appears to me to differ from all the varieties of bituminous matter hitherto discovered, suffi- ciently to form a separate species. Should my opinion be correct, I would propose that it should be distinguished by the name of Hatchetine, in reference to the eminent chemist, to whom we are indebted for the most valuable contributions towards the history and analysis of this class of natural sub- Stances. I remain, Sir, ! With much esteem, yours sincerely, J.J. CONYBEARE. eG ‘The colour varies from yellowish-white to wax and greenish- yellow. The texture is sometimes flaky (like that of spermaceti), “sometimes subgranular, like that of bees’ wax. The lustre is, inthe flaky variety, slightly glistening and pearly; in the other dull. The transparency is inthe flaky (especially in thin lamine) con- siderable: other specimens are opaque. It is very soft, not harder than soft, tallow. m* ‘Gt has no elasticity, and no edu It is very fusible; melts when p 170°. It is very light. The only analogous substances to which Hatchetine might be compared are petroleum and elastic bitumen. From the former, it differs in its consolidation; from both, in the greater part of its external character, and in its want of smell. It melts under 170°, whereas thin bitunien does not melt. even in boiling water. Like elastic bitumen, it is readily soluble in ether; and each solution, by spontaneous evaporation, leaves a viscid oily ‘matter in separate drops, but that from Hatchetine is still inodo- rous ; while that from elastic bitumen retains strongly the pecu- liar smell of that substance. Hatchetine distilled over the naked flame of a spirit-lamp assumes the bitusninous smell, and gives over a butyraceous substance of a greenish-yellow, coaly matter aced in warm water under 1821.] On Electro-magnetic Experiments. 137 remaining in the retort* ; at.a lower heat, it gives over a light oil. I have no means of ascertaining its ultimate constituents ; but have little doubt that the above characters are sufficient to authorize our considering it as distinct from petroleum, asphalt, and elastic bitumen, the only three species (with the exception of retinasphalt, which occurs under very different geognostic relations, and appears to be the result ofa very different natural process) into which substances of this class have hitherto been divided by mineralogists. The Hatchetine is found filling small contemporaneous veins lined with calcareous spar and small rock crystals (termed the Mezthyr diamonds) in the ironstone. ArTICLE XIII. Electro-magnetic Experiments. (To the Editor of the Annals of Philosophy.) SIR, Cambridge, Jan. 22, 1821. Ir, as I imagine, the following electro-magnetic experiments are new, you will oblige me by inserting them in the next number of the Annals of Philosophy. 7 _ A weight was suspended from a small horse-shoe magnet; on connecting the north pole of the magnet with the copper side of a pair of galvanic plates, the weight was attracted more strongly ; on reversing the wires, it fell. A small magnetic bar being placed in the galvanic circuit, its south pole being in connexion with the positive end of the bat- tery, the magnetism was destroyed in half a minute. A connecting wire, 1-15th of an inch diameter, being placed horizontally in the plane of the magnetic meridian, over a com- pass, the deviation of the needle was between 80° and 90°; in Oersted’s experiments, it is stated to be about 45°. On using a smaller wire, the deviation was diminished ; and when the diameter of the wire was 1-200th inch, it was less than 20°. ; This diminution of the deviation took place whether the small wire were immediately over the compass, or interposed in any other part of the circuit. When the connexion was made at the same time by the two above-mentioned wires, the smaller being three inches long, the longer five feet, the needle of a compass placed under the smaller deviated about 10°; that of another under the larger deviated * Elastic bitumen, at the same heat, gives over a yellowish oil perfectly fluid. ee On Electro-magnetic Experiments. [Fes. 80°. On removing the larger wire, the deviation under the smaller increased, &c. | i en the circuit was made by a glass tube filled with mer- cury, the deviation was the same as with a wire of the same ‘thickness ; but on removing the mercury, and coating the tube with silver leaf, the deviation was not more than between &° and 10°. | ~The electro-magnetic influence was not diminished by raisi the connecting wire to a red heat; but on interrupting the circuit by water, it was destroyed, though the connecting wire placed immediately over the compass decomposed water at each end. If the connecting wire were bent alternately from N. to S. and from 8. to N. the magnetic needle deviated to the W. of the N. in all the former, and to the E. of N. in all the latter bendings, whatever were their number, and in whatever part of the wire a! were placed. hen the connecting wire was made to pass from N, to 8. over the needle, and from 8. to N. under it, the electro-magnetic influence was doubled. A single pair of rather large plates was found, as in Oersted’s experiments, to be more efficacious than a number of plates with the usual arrangement ; but when wires from all the zinc plates were connected on one side, and from all the copper plates, on the other, the electro-magnetic influence increased with the num- ber of plates. It was found that the relative quantities of galvanism generated in different experiments might be estimated with great readiness and accuracy by using a graduated slide carrying that connecting wire over a fixed compass with a standard deviation. . I am, Sir, respectfully yours, J.C. ARTICLE Fy. ANALYsES OF Books, Untersuchungen uber den Magnetismus der Erde. Von Christo- pher Hansteen, Professor der Angewandten Mathematik. an den Norwegischen Universitat. Christiania, 1819. Researches on the Magnetism of the Earth. By Professor Han- steen, of Christiania. 1 vol. 4to. 650 pages. I HAVE just received a copy of the first volume of this cele- brated work, which I have been very anxious to see. I am unwilling to peruse it till I recover the Atlas, which ought to have accompanied it, and which has been unfortunately lost on the way between Christiania and London ; but I cannot avoid 1821.] ‘Analyses of Books. | 139 immediately announcing it to the public, and pointing out the importance of ‘publishing it in an English translation. I shall take a future opportunity of giving a detailed account of it to the readers ‘of the Annals of Philosophy. At present I shall merely give the titles of the great divisions of the work, and add some important facts and corrections which Professor Hansteen has pointed out to me in a letter, dated Christiania, Nov. 21, 1820. After an introduction of 14 pages, Prof. Hansteen treats of, ‘1. Halley’s lines and of their motion between 1600 and 1800. 2. Of the lines of inclination, and of the magnetic intensity. 3. The number; position, and periodalgyration of the magnetic poles round the pole of the earth. 5. Calculation of Halley’s lines from the first imperfect theory of Euler. 5. Mathematical theory of magnetism. 6. Application of the theory of magne- tism to the theory of the magnetical declination, inclination, and intensity, in a given place, whose geographical position is known. 7. A more accurate determination of the position of the magne- tical axes, their size and relative intensities.. 8. Of the daily variation of the needle. The whole terminates with very ample tables of the declination and dip in various parts of the earth. Prof. Hansteen requests me to inform the public that his seventh chart, showing the dip of the magnetic needle, is erro- neous, because, when projecting it, he was unacquainted with the original observations made in the course of a voyage to the Northern Pacific Ocean by Capt. Cook and Mr. William Bayley. Led astray by some observations of Krusenstern, he was induced in the corrections and additions to his.work, p. 21, 22, to con- tradict M. Biot, who insists, in his Traité de Physique, tom. iii. p. 131, that the line of no dip (magnetic equator) cuts the equa- tor of the earth three or four times. ‘ But,’ continues Prof. Hansteen, ‘ Biot is in the right, and the accompanying cor- rected chart shows the dipping lines in the Pacific in their right form. Your mentioning in your Annals, in a few words, that I myself acknowledge my error, will be conferring a particular obligation on me.” ““ On observing the oscillations of a magnetical steel cylinder, suspended by a silk-worm thread in a small box with glass openings, [ have made the curious discovery that the magneti- cal intensity of the earth has a daily and annual variation. _ By a chronometer of Arnold’s, I observe five times every day, at stated hours, the time required for completing 300 vibrations ; and these observations I have already continued for nearly a year. From early in the morning, the intensity is on the ‘decrease until between 10 and 11 o’clock in the forenoon, when - at has reached its minimum. From this time it increases, at first slowly, afterwards more rapidly, till it reaches the maximum at four o’clock afternoon in the winter, and between six and eight in the summer, At times it does not reach this maximum 140 Analyses of Books. [Fes. till about ten in the evening. In the winter, the intensity is much stronger than in summer. The greatest intensity appears to happen in the month of January; the least happened this year (1820) on the 18th of July. The daily variations are much greater in summer than in winter. “‘ Great irregularities occur at times, especially on those days, when the moon passes the equator, or on the quarter days of the moon. Similar great changes I have observed during the equi- noxes. The influence of the northern lights, as already observed by Mr, Humboldt, is very remarkable, and frequently it does not regain its former strength till after the lapse of 24 hours.” “I have likewise found in the same manner that every per- pendicular object, of whatever materials ; for instance, a tree, the wall of a house, &c. has a magnetic north pole at the foot, and a south pole at the top.”—T. ip An Essay on Chemical Analysis, chiefly translated from the Fourth Volume of the last Edition of the Traité de Chimie Elémentaire of L, J. Thenard, with Additions, comprehending the latest Discoveries and Improvements in this Branch of the Science. With Plates. By John George Children, FRSL. and E. FAS. &c. &e. — Chemical analysis, owing to the great number of simple sub- stances with which the science has been enriched, and the con- sequent increase of compounds, is now rendered a subject of considerable difficulty and- complexity. These have, however, in many instances, been fortunately diminished by the discovery of the doctrine of definite proportions, which the chemist may now avail himself of in proof of the justice of his views, and the correctness of his analyses. It must, however, at the same time be admitted, that this discovery, vast as its importance is, is liable to be, and probably has been, misused by some who have deter- mined what the composition of a body ought to be, rather by a comparison of numbers than by the dow and tedious process of analysis. It is, however, to be remarked that the doctrine of definite proportions, although it may be called in to prove the correctness.of an analysis, ought never to supply the place of one—I do not mean that it is not allowable to form conjectures as to the composition of bodies by the aid of the atomic theory; I only mean that these conjectures should not be stated as facts to be absolutely relied on. Mr. Children has stated so clearly the motive which induced him to undertake the present wie that I shall give his own words on the occasion: “ On reading the fourth volume of M. Thenard’s Traité de Chimie Elémentaire, Theorique et Pratique, which treats exclusively of chemical analysis, and in a manner much more satisfactory and complete than any other 1821.] An Essay on Chemical Analysis. 14) work I had before met with, it struck me that if translated into our language, it could not fail to be of great utility to the English chemist.” Mr. Children then observes, that to the first edition of the author he had added the valuable matter contained in the second edition, which appeared while the translation was proceeding. Mr. Children was, I think, judicious in the choice of the author whom he selected, for giving to the English chemist a more full account of the minutiz of analysis, than had ever a in our own language. : hose parts of the work which depended merely upon the trans- lator, it is hardly requisite to state have been accurately per- formed by Mr. Children ; but it would be doing him great injus- tice not to mention, that much new and valuable information, not to be found in the original work, has been added: in saying this,’ I do not mean merely that such notices have been collected as are within the reach of every one who inspects the various sources of chemical knowledge; but on several occasions Mr. Children has given us the results of his own experiments and observations, and which, i think, cannot fail to be useful. The directions for the use of the blow-pipe, and the appearance which certain sub- stances present after its action, form a very excellent part of the appendix ; and Mr. Children shows, by the attention which he has paid to the subject, that he has duly appreciated the value of — ~ Bergman’s remarks upon the blow-pipe, with which he very aptly concludes his remarks on this useful instrument. On the subjects of the analyses of vegetable and animal sub- stances, a concise but clear account of the proximate principles of vegetable bodies has been introduced. It is, however, to be observed, that by an oversight, the very widely diffused and valuable vegetable product tannin has been totally omitted, nor is its combination with gelatine and albumen mentioned. On the subject of the atomic theory, Mr. Children justly remarks, ‘that in the great progress which chemistry has made within a few years, one of its most important steps towards per- fection as a science, is the establishment of the atomic theory.” A knowledge of the principles upon which it is founded, afford- img, he observes, to the practical analyst an easy and almost in- fallible test of the accuracy of his experiments. Mr. Children then gives a sketeh of the atomic theory, which: will afford the young chemist much useful information on this curious and highly interesting topic. It may be, perhaps, out of place here, but 1 cannot help remarking, the difference which exists among chemical philosophers as to the numbers by which they represent hydrogen and oxygen; for it will be found that they differ considerably both in quantity and proportion. Thus Mr. Dalton represents hydrogen by 1; and oxygen by 7. Sir H. Davy, hydrogen, 2, and oxygen, 15. Dr. Henry, hydro- gen, 1, and oxygen, 7:5. Mr. Brande agrees with Dr. Henry ~ 142 _\ Analyses of Books... .» [Fes. Dr, Wollaston.represents hydrogen by 1:32, and en by 10,, Dr. Thomson, Nabe i 0-125, and ated 1, teh ah to, be regretted that these variations should exist: they produce the ill effect of appearing to render a subject difficult which is easy of explanation, by merely stating, as Mr, Children has done, that, whatever portion we take of a compound mass, “ it must con-, tain a certain number of atoms of each substance ; and although we know nothing of their actual number, still we obtain by ana-. lysis the proportion that the atoms. of one kind bears to those of the other; or, supposing the compound to contain an equal, number of each, the proportionate weights,of the atoms them- selves.” . On the subject of the analysis of mineral waters,.Mr. Children, has. added much to the original work of M, Thenard. He has particularly noticed the opinions of the late Dr. Murray, to the ~— of whose views on this subject, as well as on every other, | wish (however useless) to add my assent. | confess, how- ever, for reasons which I shall take another opportunity of stating, that I do not accede to the correctness of his views when sup- posing that those salts which exist in a mineral water are such as result from the union of those acids and bases as form the most soluble compounds. Whatever I may advance on this subject, I am nevertheless of opinion that the results obtained. by Dr. Murray in his analysis of sea water, show that the mode; which he employed. was generally correct; and Mr. Children has judiciously inserted it. - In the Appendix, Mr. Children has given Dr. Marcet’s method of detecting the presence of arsenic, observing “ that. the unhappy frequency with which arsenic has been employed. for most nefarious, purposes, venders an. infallible mode of detecting its presence, when in very minute quantity, a great desideratum in medical jurisprudence.” “ It has been objected,” says: Mr. Children, ‘ to this test, that if a phosphate be present, its, indications are ambiguous; for the colour of phosphate of silver is not much unlike that. of arsenite of silver. An expe- rienced eye, however, will readily distinguish between them; the latter being of a brighter yellow than the former.’’, I must con- fess that this ambiguity is.to me an insuperable. objection to, what is termed the silver test. | have seen precipitates occa= sioned by the phosphoric and arsenious acids so. similar in colour that 1 could not distinguish any difference, and much less, any variation which would be.a i guide for deciding, om the solemn and unhappy: occasions. in which evidence. is. required. It is, however, but proper to add, that Dr. Marcet no longer depends upon the evidence afforded by colour of the precipitate of arsenite of silver, unless it be corroborated by, other appearances. z | - © The best method that I know of,” says Mr. Children, “is to passa current of sulphuretted hydrogen gas into a suspected. oe 182k] An Essay on Chemical. Analysis, 143 solution, when, if arsenious acid be present, it will occasion the | SapPevanes of'a fine lemon-yellow colour through the awe hae will have no action. on phosphate of silver. That substance, however, may prevent the yellow colour from appearing, although arsenious acid be actually contained in the solution; but the addition. of a very few drops, of very. dilute pure nitric acid. will immediately produce it. If, therefore, both the silver test and the sulphuretted hydrogen concur in indicating the presence of the poison, no reasonable doubt can be entertained respecting it; but it is certainly an additional satisfaction to reduce a por- tion. to. the metallic state, or at least to sublime the oxide so as to. render its peculiar albaceous odour distinctly evident, where enough can be procured for the purpose, though that cannot often be expected.” . IL shall offer one or two observations upon this statement, and, T-trust Mr. Children will believe that I do not object. upon what appears to me; friyolous grounds. In the first place, I think it more convenient. to employ a solution of sulphuretted hydrogen in, water than to pass the gas through the suspected solution ; the same effects are produced, and to pass gas through so small a quantity of fluid as it is sometimes necessary to operate upon, increases the difficulty, but not the certainty of the process. It should be observed that no hydrosulphuret in solution should be employed instead of the mere gas; and the arsenious acid should be dissolved simply in water without the aid of any alkali; for this, if | remember rightly, interferes with the action of the sul- phuretted hydrogen. With respect to the employment of a nitric acid, in.case phos- phoric salts be present, 1 entertain considerable.doubt. . Nitric acid, decomposes. sulphuretted hydrogen, precipitating the sul- phur, which may interfere with the process if the acid be em- loyed in excess. | Mr. Children states that he finds that sulphuretted hydrogen gives a decided yellow colour to an ounce measure of distilled water, containing one drop of a saturated solution of arsenious acid, equal to 8th of a grain of the solid acid, or about ~,,th of the whole weight of the solution. Two or three drops of phosphate of soda prevented its action, but a little very dilute acetic acid immediately produced the yellow colour. Mr. Chil- dren properly observes that the acetic acid ought to be pure, and not, such as. has been distilled through a metallic worm. _ It appears from.this statement that the power of sulphuretted hydrogen.as a test of arsenic is very great. It is singular. that phosphate of soda should prevent its action; and I would sub-. mit, whether this very circumstance cannot be taken advantage of as.an additional proof of the presence of arsenic. _. In a.work of this nature, embracing so many and such varied, points of the science, it is not to be wondered at that some few inaccuracies.should appear. As an example of these, | woulp 144 Proceedings of Philosophical Societies, [Frs. mention that Mr. Children does not seem to have, in all cases, clearly distinguished between chlorides and dry muriates, and the compounds of muriatic gas: thus, in p. 229, we are told that. 100 parts of hydrochloric acid saturate 102 of lime. This must be what was formerly called dry muriatic acid—a substance of which Mr. Children will not admit the existence ; but it will be observed in other cases, especially in the note at the bottom of this page, that Mr. Children re ar | refers to hydrochloric acid, as a compound of hydrogen and chlorine. I confess I see no advantage in using the term barya instead of baryta, or even barytes ; and if the term hydrochloric acid is to be admitted, I cannot conceive on what grounds hydrosulphuric acid for sulphu- retted hydrogen is to be rejected. 1 had intended to have made various other references to the useful additions contained in the Appendix ; but I have already extended this article to so great a length that I must conclude with observing, that this work contains in a moderate compass what can scarcely be found without numerous references to a variety of chemical authorities ; and I strongly recommend it as _ worthy of the confidence and study of the young analyst.— Ed. Note by the Editor.—In the last number of the Annals, some errors occurred in the analysis of the Edinburgh Pharmacopeeia. In mentioning the Oxzdum Hydrargyri Cinereum, the quan- tity of lime contained in the lime-water is much overrated. Under common circumstances, the quantity directed by the College cannot be considered as too large. Page 61, line 10 from the bottom, for 42 read 32. 2 from the bottom, for one-ninth part read one- third part. ArTICLE XV. Proceedings of Philosophical Societies. ROYAL SOCIETY. In the last number of the Annals, the address of Sir Humphry Davy, on taking the chair as President, was given with a degree of brevity so little suited to the occasion, that I am happy to be able now to give more at length the heads of his discourse. The President commenced his address by repeating his thanks to the Fellows of the Royal Society forthe distinguished honour’ which they had done him by placing him in the chair. He stated his entire devotion to the cause of science, and assured the Society that his feelings were deep, and would be permanent. - 1821.] Royal Society. 145 Sir H. Davy then proceeded to point out the difficulties which attended the pursuits of ap ee at an early period, and hence existed the necessity of placing in the rooms of the Royal Society a collection of such machines as were useful in the pro- gress of experimental knowledge. From the improvements. which had been made in mechanical and chemical arts, he observed there were now but few occasions in which individuals could not conduct their experiments in their own laboratories ; he expressed a hope, however, that on occasions of importance, and which might incur great expense, the proposers would not fail to recur to the Society. The President then observed, that, owing to the progress of science, various associations had been formed for its advance- ment since the period when the Royal Society stood alone, and he expressed a hope that it would always preserve the most amicable relations with these new Societies ; and that when any new facts of importance were observed by them, they would not fail to.communicate them to the Royal, as the parent Society, whose records, he observed, contain all that was valuable from the time of our early philosophers. He disclaimed, how- ever, all wish on the part of the Royal Society to exercise any authority over the more recent associations, whose objects were similar. After some further remarks on the inexhaustibility of the sub- jects of scientific pursuit, he observed that philosophers, like the early cultivators in a great new continent, in proportion as they clear the country, discover more and more the vastness of the surrounding wilds. As the chart of a new country is essential in guiding the traveller, so, he continued, might the aspects and. «characters of new objects be useful to scientific investigation ; and with this view the President offered some observations respecting those difficult departments of inquiry which appeared most capable of improvement. The pure mathematics, as a work of intellectual combination, are, he conceived, incapable of receiv- ing aid from external phenomena; he considered them, how- ever, at the present moment as promising new applications, observing that many departments of philosophical inquiry, to which the mathematics were formerly inapplicable, are now ‘brought under its dominion. After the discovery of the Georgium Sidus there appeared but little probability that new planetary bodies should be discovered. mearer to our earth than any of those already known; yet this supposition, the President observed, had been found erroneous, owing to our limited conceptions of nature. The discovery of bodies smaller than satellites, but having the motions of primary planets, has opened new views of the arrangement of the solar system. Sir H. Davy then, alluding to astronomy, as the most ancient New Series, vou. 1. K 146 Proceedings of Philosophical Societies. (Fes. and perfect of the sciences, pointed out, as subjects for investi- tion, the nature of the systems of the fixed stars, their changes, e relations of cometary bodies to the sun, and the motions of those meteors which throw down showers of stones ; for ‘fn. a system, he observed, in which all is harmony, even these must be governed by fixed laws, and intended for definite purposes. | he great question of universal gravitation, and its connexion with the figure of the earth, the President observed, had been long sived. . By the mechanical refinements of a Fellow of the Society, new means had been devised of estimating the force of vity with exactitude. Sir H. Davy stated the desire which he new was entertained by the Royal Academy of Sciences at Paris to connect their labours with those carried on by the com- mand of the Board of Ordnance in Britain: should this take place, there would then be established, he observed, on the highest authority, an admeasurement of 1-18th of the whole circumference of the earth—a great record for posterity, and an honour to our own times. : As connected with the subject of the figure of the earth, Sir H. Davy referred to the late voyage to the Arctic regions, which, he observed, presented hopes of greater discoveries; and he made honourable mention of those es whom the expedition was planned and executed—an expedition which he characterized as worthy of the greatest maritime nation in the world. _ The discoveries of Huygens, Newton, and Wollaston, in the theory of light and vision, were stated to have been followed by those of Malus. The President then alluded to the subject of the polarization of light, and the labours of other eminent philoso- phers; and expressed an opinion that this discovery would establish a new connexion between mechanical and chemical philosophy. | The subject of heat as connected with that of light was remarked as having lately afforded a rich harvest of discovery. The applications oF the doctrine of heat to the atomic or corpus- cular philosophy of chemistry were represented by the President as abounding in new views ; and he noticed several facts which seemed to point to some general law on the subject: 1. The gpberent equable motion of radiant matter, or light and heat, through space. 2, The equable expansion of all elastic fluids by equal increments of temperature. 3. The contraction or expansion of gases by chemical changes, in some direct ratio to _ their original volume. 4. The circumstance that the elementary et of all bodies appear to possess the same quantity of eat. _ The wonderful electrical instrument of Volta had done more, it was remarked, for the obscure parts of physics and chemistry, than the microscope for natural history, or even the telescope 1821.) Royal Society. 147 for astronomy. Sir H. Davy then,alluded. to the electro-magne- tic experiments of Oersted, and the award of,the Copleian medal to that philosopher. The. subject. of chemistry next claimed the attention of the President;:and he justly remarked, that, to, pomt out all the objects worthy of inquiry in this branch of science would require many sittings of the Society... Among the more important, desi- derata, were mentioned the knowledge of the nature of the com- binations of the principle of the fluor spar, and the metallization of ammonia, together with the connexion between, mechanical and chemical, phenomena in the action of voltaic electricity, Sir H. Davy then congratulated the Society onthe rapid advances made in the theory of definite proportions, since. it was first advanced in a distinct form, by the ingenuity, of Mr. Dalton, and he stated the promise, which it affords of solving the recondite changes in. the particles of matter, by laws depending upon their weight, number, and figure. As connected with, definite propor- tions, the crystallizations, or regular forms of inorganic matter, were next noticed, and were observed,to depend upon the motion of the combinations of elementary particles, to which.the laws of electrical polarity and the polarisation of light seemed to have relation. Alluding to the difficulty of framing an hypothesis.to account for the origin of the primary arrangements of the crystal- line matter of the globe, Sir H. Davy stated the two. principal facts which present analogies on the subject : One, that the form of the earthis that which would result, supposing it to, haye been originally fluid ; and the other, that in lavas, masses decidedly of igneous origin, crystalline substances similar to those belong- tng te the primary rocks, are found in abundance. he President then noticed the regular gradations which occur in the phenomena of nature, from the motions of the great masses of the heavenly bodies, to the imperceptible changes which, produce the phenomena of crystallization ; and, when this ends, the series. of animated. nature governed by a distinct set of Jaws, begins; and as important objects of investigation, the functions and. operations of organized beings. were pointed out ; as, for instance, those refined chemical processes by which the death and decay of one: species. afford nourishment for another and. higher order; by which the water and inert matter of the soil and the atmosphere are converted into, delicately organized structures, filled with life and beauty. In vegetable physiology, the motion of the sap, the functions of the leaves, and the nature of the organs of assimilation, were mentioned as phenomena still remaining for investigation ; and in,animal physiology, the subjects were stated to be still more varied, obscure, and of a higher order; and a hope was expressed by the President, that the philosophers of the schools of Grewe and Hunter would. not, cease their efforts, for the improvement of K 2 148 Proceedings of Philosophical Societies. [Fes. these branches of science, the first of great utility to agriculture, and the latter, to medicine. Sir H. Davy then expressed his conviction that the spirit of philosophy, awakened by the great masters, Bacon and Newton, would guide the future proceedings of the Fellows of the Royal Society. The sober and cautious method of inductive reasonings of these great Sel eo he described as the germ of truth and of permanency in all the sciences ; and he trusted that those who were so fortunate as to kindle the light of new discoveries would use them, not for the purpose of dazzling the organs of intellectual vision, but rather to enlighten, by showing objects in their true form and colours. A hope was also expressed by the President, that our philoso- hers will attach no undue importance to hypotheses, treating them rather as parts of the scaffolding of the building of science than as belonging to its foundations, materials, or ornaments ; that they will look where it is possible, to practical applications in science, without forgetting the dignity of their pursuit, the noblest end of which is to exalt the powers of the human mind, and to increase the sphere of intellectual enjoyment, by enlarg- ing our views of nature, and of the power, wisdom, and goodness, of the author of nature. After nee to the right which the Royal Society had to expect proofs of the zeal of those members in promoting its pro- gress who had not yet contributed to it; and after stating that the Society would always consider the success of past, as pledges of future contributions, the President concluded a brief but luminous and impressive review of the present state of the sciences, with observing, “ For myself, I can only say that I shall be most happy to give, in any way, assistance, either by advice, or experiments, in promoting the progress of discovery. And though your good opinion has, as it were, honoured me with a rank similar to that of a General, I shall be always happy to act as a private soldier in the ranks of science.” “ Let us then labour together,” said the President, ‘ and steadily endeavour to gain what are, perhaps, the noblest objects of ambition—conquests in the field of natural knowledge ; acqui- sitions which may be useful to our fellow creatures. Let it not be said that at a period when our empire was at the highest pitch of greatness, the sciences began to decline: let us rather hope that posterity will find in our records proofs that we were not unworthy of the times in which we lived.” Jan. 18.—A paper of Dr. Davy’s was read, giving an account of his inquiries relative to the urinary organs, and secretion of two species of rana common in Ceylon: from which it appears, first, that the bladder of the bull frog and brown toad (the two Species in question) is a genuine receptacle of urine, which it receives from the cloaca, in which the ureters terminate ; and 1821.] Geological Society. 149 secondly, that their urine is not at all analogous to that of other animals of the order amphibia, being very dilute, containing urea and certain salts, but no appreciable quantity of lithic acid. This peculiarity of urine, so well adapted to the size and struc- ture of the bladder, is the more remarkable, as the favourite food of these animals is the same as that of small lizards, whose urine is of a butyraceous consistence, and nearly pure lithic acid. Hence, and from other facts mentioned by the author, he adduces the conclusion that the nature of urine, in every instance, depends much more on the peculiar action and structure of the secreting organs than on peculiarities of diet, or of the circulat- ing fluids. , At the same meeting, a paper, by Capt. Kater, was read, entitled “‘ An Account of the Comparison of various British Standards of Linear Measure.” Jan. 25.—The reading of the Bakerian lecture, by Captain Kater, on the form and the kinds of steel most proper to be em- ployed in making magnetic needles, was commenced. At the same meeting was read, “ An Account of a Micro- meter made of Rock Crystal,” by G. Dollond, FRS. _ The improvement consists in making a sphere of rock crystal, and applying it in the place of the usual eye glass ofa telescope, and from its natural double refracting property rendering it use- ful as a micrometer. Jan. 5.—A paper on the Geology of the North-eastern Border of Bengal, by H. T. Colebrooke, Esq. VPGS. &c. was read. The Brahmoputra river, which unites its stream with the Ganges at a short distance from their common junction with the sea, after a long course in the Himalaya, passes through the mountains of Aslam, and issues into the plain at the north-east corner of Ben- gal. At that position is a hill at Jogigopha,’ which is connected with the Rhotan mountains, and which consists chiefly of a large hemispherical mass of gneiss having strata, or rather masses, of granite on the north-eastern and western sides. On the opposite’ or southern bank of the river is the hill of Pagnalath, which also appears to be composed of gneiss, the masses running from N.E. to 8.W. at an angle of 45°. At Givalpara, a few miles to the east of Paglanath, granite is found. . The same rocks occur again at Dhabui, a low hill, partly covered with alluvial soil, near the confluence of the Gadadhar. Blocks of primitive greenstone are also met with here in various parts of the bank of the river. At the confluence of the Kelanke river, which issues from the Garo hills, a little lower down is a precipitous bank, exhibiting graphic granite, and gneiss. In the bed of the river, blocks of compact felspar, primitive ane, and quartz, united with felspar and hornblende, are ound. 150 Scientific Intelligence. | [Fes. On the left bank of the Brahmoputra and the Caribari hills, or cliffs, which, for aconsiderable extent, consist generally of slate- clay, horizontally disposed, with a stratum of yellow (or more properly green) sand lying above it, indurated at the bottom in — some places, and accompanied with ferruginous concretions. In many places, a stratum of clay i8 found resting on the green sand; and over it, the bank is composed of white or red sand mixed with gravel. 1 , In different parts of the cliff, coarse-grained sandstone, clay ironstone concretions, nodules of slate clay and fossil wood have been found. In a bed of organic remains, situated under a small hill on the cliff, about seven feet below the level of the highest flood of the river, and 150 feet above the level of the sea, with layers of clay above and beneath, and resting upon alternate strata of sand and clay, a variety of fossils have been found, resembling in characters those which have been discovered in similar strata in the London and Paris basins. On the banks of the Festa where it issues from the Rhotan mountains to:descend into North Bengal, the rocks are found to consist principally of sandstone, containing much mica. Ferru- ginous sandstone was found in one place, and wood coal in another, where the sandstone comprises large pebbles. The banks of the Subeck, another river which descends from the Rhotan mountains, present similar strata. Articte XVI. SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS CONNECTED WITH SCIENCE. I. Crystallization of Red Oxide of Copper by Heat. Mr. Chenevix, in his analysis of the arseniate of copper and of iron (Phil. Trans. 1801), has remarked, that by exposing oxide, hydrate, or carbonate of copper, without addition, to a violent heat, in an open crucible, he frequently obtained the red oxide of copper, presenting all the properties of this species of ore. On one occasion, he says, that the well-experienced eye of the Count de Bournon recognized a lump of it to be a mass of semi-fused artificial red copper ore. Some time since I exposed a quantity of protoxide of copper to heat and air in an iron vessel with the intention of converting it into peroxide ; I accidentally observed that the characters of the red oxide of copper were even more distinctly marked than they appear to have been in the mass obtained by Mr. Chenevix. The bottom of the mass is in the form of that of the vessel in which the copper was burned—a portion ofa sphere. The mass consists of layers of pure copper, and of the red oxide, arcs.) 1821.] ) Scientific Intelligence. } 151 alternating, but not with apparent regularity. The pure copper and red oxide are sometimes intermixed in the same layer. The red oxide is distinctly, though minutely, crystallized in the form of the primary octohedron, and of the cube, and in intermediate varieties. The pure copper is also in extremely small and brilliant crystals, but so minute that I cannot perceive their forms by the help even of the strongest glass, The greater part of the surface of the mass is tinged of a green colour; portions of it are vitreous and transparent. The green colour is found, by the assistance of a strong glass, to be owing to the presence of fibrous crystals which are translucent, but too minute for the determination of their form. They have greatly the colour and appearance of the phosphate of lead.—Ep. II. Description of Two New Mineral Substances, found by Dr. Mac- culloch in Rum and Mull, — ‘«‘ The last mineral substance,” says Dr. Macculloch, ‘ which re- mains to be enumerated, being hitherto undescribed, it is necessary to enter into a minuter detail respecting it. Many years have passed since I discovered it both here (Rum) and in Fife; and the description has been hitherto delayed in hopes of finding larger specimens, better adapted for elucidating its history. These hopes have been hitherto disappointed, and I must therefore give it, however imperfect ; in hopes that other mineralogists will hereafter supply the deficiencies. When recently broken it is of a green colour; varying from the trans- parent yellow green of the finest olivin (or chrysolite) which it some- times resembles so as to be undistinguishable, to the dull muddy green of steatite, to which in this case it bears an equal resemblance. In a@ few hours after being taken from its repository, or exposed to the air, it turns darker, and shortly becomes black ; a change which also occurs within the rock at the depth of an inch or more from the surface. In this case, the transparent variety puts on the external aspect with the lustre of jet: while the opake one preserves its dull surface, and more nearly resembles black chalk. Notwithstanding this change, the mineral when in small fragments still continues to transmit light. The first variety remains perfectly translucent, and presents in some spe- cimens the fine brown orange of cinnamon stone, in others a rich bottle or olive green, The other appears also of an olive green, but it is not more translucent than ore of the same thickness. When powdered, the one is of a snuffy brown, the other of a dirty olive. The structure of the first variety is generally conchoidal, that of the second is com- monly intermediate between the conchoidal and granular. It is so soft as to be scratched by a quill, and is brittle; easily breaking into minute irregular fragments. The specific gravity is 2°020. © With respect to its chemical habits, it remains unchanged before the blow- pipe ; neither cracking nor sensibly altering its colour or translucency, It is apparently as refractory as quartz; a remarkable circumstance, when the quantity of iron in it is considered. It is acted on by muriatic acid, giving indications of a considerable proportion of iron, with a little alumina; but the principal constituent appears to be silica. There are no traces of lime or of manganese. ‘The very minute quantity L 152 Scientific Intelligence. [Fes. possessed for examination, prevents any more accurate detail of its composition. «It is found imbedded in the amygdaloids of the cliffs of Scuir more, the base being either a basalt, or a black indurated claystone. ‘The nodules are generally round, and vary from the size of a radish seed to that of a pea or upwards. Occasionally they are oblong and com- pressed, and sometimes scale off in concentric crusts. In a few in- stances they are hollow within, the interior surface having a blistered aspect ; or else the cavity of the amygdaloid is covered with the sub- stance in a form resembling that of an exudation. More rarely still the nodule is compounded, containing a Maree of calcareous spar within an investing crust of the mineral. hen long exposed to the air, it decomposes in the form of a rusty powder, which 1s thus occa- sionally found filling those cavities that are visible on the surface of the fragments in which it is found. The variety from Fife differs from that of Rum, in being less regular in form, and less frequently round, while it is commonly also of a larger size. From the most. characte- ristic quality of this mineral, the term chlorophzite may be conve- niently adopted for distinguishing it.”? Dr. Macculloch adds, that he has since seen this mineral brought from Iceland by Major Peterson. (Western Islands, vol. i. p. 504.) | “In reviewing some of the amygdaloids collected in Mull, I diseo- vered a non-descript substance intermixed with some prehnite, but too small in quantity for examination. ‘Having since found the same mi- neral in greater abundance in Glen Farg, I shall give the best descrip~ tion of it I am enabled to do from these specimens, as I cannot now assign the exact locality of the former. It has hitherto escaped the observation of mineralogists, and the description, however imperfect, will therefore be of use, by directing their attention towards it, and thus probably ascertaining its existence in other places. Its externah characters are very limited, since it consists of a loose white powder, somewhat coarser than silica as it is obtained from the silicated alka- lies, gritty between the teeth. but not so hard as to scratch glass. “It does not effervesce with acids, and before the blow-pipe it melts immediately into a transparent colourless bead, with apparently the same facility as glass. It is certainly at least more fusible than datholite. Ihave not been able, from its condition, to determine its yr gravity. On attempting to analyze the very minute quantity at could be spared for that purpose, it was found to consist princi- pally of silica. A small quantity of lime was taken up by muriatic acid, but its fusibility was not destroyed by that treatment. When treated, however, in a similar manner by sulphuric acid, the fusibility was destroyed. No alkali was found in it, nor any boracic acid, nor any tifaces of metallic matter. It is not easy therefore to account for its great fusibility, unless it should contain the new alkali. In this uncertain state must its chemical composition remain, until other spe- cimens are procured to admit of a repetition of these experiments on 2 more extensive scale. It is found filling irregular cavities in the amygdaloid of the valley above-mentioned, so well known to mineral- ogists ; where it is accompanied by analcime, mesotype, prelnite and calcareous spar. There is no appearance of decomposition in the 1821.] Scientific Intelligence. 153 peaked a | minerals, and: I may add that the specimens in question were broken from a fresh rock in which they were deeply imbedded.. The preceding characters seem to distinguish it for the present from all the mineral substances hitherto described; and the term conite appears well adapted for it, as being expressive of its most conspicuous feature. | «‘ On this substance I shall only remark as I recently did on treating of Rum, that it is preferable to erect a species, though it should after- wards prove a variety of some known substance, than to neglect the obscure characters which minerals often present. It is to greater accuracy of research and of knowledge that we are indebted to the recent rapid augmentation of the list of minerals.” (Vol. i. p. 578.) III. Production of Artificial Cold. When on Ben More in Mull, about 3097 feet high, Dr. Macculloch made the following observation.—* On this mountain I was accident- ally led to observe the degree of cold produced by the mixture of ice and alcohol. A storm of hail had fallen, accompanied by a tempera- ture below freezing. Some whiskey, the usual appendage of a High- land vieticum, being produced, I was obliged to dilute it by putting some hailinto the cup. In an instant the metal was covered with ice, and frozen to the glass: on trial, the quicksilver in the thermometer sunk into the bulb. On repeating the experiment afterwards with common alcohol, the cold was found to amount to 49° or 50°. It presents a convenient method of obtaining a low temperature, when other less common materials are not at hand.” (Western Islands, vol. i. p. 534.) . IV. Mercurial Atmosphere. It has been long admitted that in the upper part of the thermometer and barometer an atmosphere of mercury exists, having a very small degree of tension; and Mr. Faraday has shown, by the following simple experiment, that a mercurial atmosphere may exist without removing the air. A small portion of mercury was put through a fun- nel into a clean dry bottle, capable of holding about six ounces, and formed a stratum at the bottom, not one-eighth of an inch in thickness 5. particular care was taken that none of the mercury should adhere to the upper part of the inside of the bottle. A small piece of leaf-gold was then attached to the under part of the stopper of the bottle; sa that when the stopper was put into its place, the leaf-gold was inclosed in the bottle. It was then set aside in a safe place, which happened to be both dark and cool, and left for between six weeks and two months. At the end of that time, it was examined, and the leaf-gold was found whitened by a quantity of mercury, through every part of the bottle, and mercury remained apparently just as before. This experiment was repeated several times, showing that mercury is always surrounded by an atmosphere of the same substance.—(Faraday, Quarterly Journal of Science, No. xx. p. 355.) V. Sulphuret of Chrome. Mr. I. L. Lassaigne has obtained this compound by the following process : Chloride of chrome was prepared by boiling chromic acid with excess of muriatic and evaporating to dryness. It was then mixed 154 Nevo, Stientific\ Books: (ee with five times its weight of anipban and heated to whiteness in a bent glass tube. The resulting sulphuret of chrome was blackish-grey colour ; it is unctuous to the feel, very light, and readily falling to powder; when rubbed on bodies, it leaves marks similar to those of i Heated in a platina crucible, it burns like pyrophorous, giving fumes of sulphurous acid, and leaving deep-green coloured oxide of chrome. It is not readily acted upon by nitric acid: but when this acid is mixed with muriatic, it is easily dissolved. It ig, composed of chrome, 100; and sulphur, 10°54. By mixing equal parts of chromate of potash and sulphur, and-heating the mixture in close vessels, green oxide of chrome was economically obtained by M. Lassaigne. It is to be washed with water to dissolve the sulphate and sulphuret of potash, which leaves the oxide of chrome pure. Equally fine oxide of chrome was obtained by heating sulphur with the produce of the evaporation of the solution of chromate of iron, treated by nitre, to which a little sulphuric acid had been previously added to precipitate the earthy matters which had been dissolved. Owing to a mistake of the engraver, it has been found requisite to give a new Plate of Mr. Pratt's Clinometer, which the reader is requested to substitute for that in the last number of the Annals, ArtTicLte XVII. NEW SCIENTIFIC BOOKS PREPARING FOR PUBLICATION. Dr. Good is preparing for publication, The Study of Medicine, comprising its Physiology, Pathology, and Practice. ‘These volumes, in addition to that lately published on Nosology, and dedicated, by permission, to the College of Physicians, will complete the Author’s design ; and constitute an entire body of Medical Science, equally adapted to the use of Lecturers, Practitioners, and Students. Travels in Syria and Mount Sinai, by the late J. L. Burckhard, are in the press. ! A work, entitled “ Practical Economy, or Hints for the Applica- tion of Modern Discoveries to the Purposes of Domestic Life,” is pre- paring for publication. Mr. Haden, of Sloane-street, is about to publish a Monthly Journal of Medicine, addressed principally to unprofessional » ytd The work will teach the prevention rather than the cure of disorders; at the same time that it will point out how the friends of the sick may, in the best way, assist their medical men in his treatment, and otherwise — show how health may be preserved, and disease warded off. JUST PUBLISHED. An Inquiry into the Nature and Treatment of Gravel, Calculus, and other Diseases connected with a deranged Operation of the Urinary Organs. By William Prout, MD. FRS. 8vo. ‘7s. boards. ~ 1821.] New Patents. 155 An Essay on Sea Bathing, in preserving Health, and as a Remed in Disease, especially Nervous, Scrophulous, &c. By J. W. Williams, Member of the College of Surgeons, London. 12mo. 5s.6d. . Cases illustrating the improved Treatment of Stricture in the Ure- thraand Rectum. By James Arnott. 8vo. 4s. 6d. A Dictionary of Chemistry, on the Basis of Mr. Nicholson’s; in which the Principles of the Science are investigated anew. By An- drew Ure, MD. 8vo. 10. 1s. boards. Practical Observations in Midwifery ; witha Selection of Cases. By John Ramsbotham, MD. 8vo. PartI. 10s. 6d. Practical Observations on Chronic Affections of the Digestive Or- gans, and on Bilious and Nervous Disorders. By John Thomas, MD. 8vo. 6s. Illustrations of the great Operations of Surgery. By Charles Bell. Part I. Platescoloured. 14. 1s. Universal Science ; or the Cabinet of Nature and Art ; comprising various Selections from useful Discoveries in the Arts and Sciences. By Alex. Jamieson. 2 vols. 12mo. 16s. ArticLte XVIII. NEW PATENTS. James Ransome, of Ipswich, iron-founder, and Robert Ransome, of Colchester, iron-founder, for an improvement upon an invention by James Ransome, for which he now hath a patent, June 1, 1816, for certain improvements on ploughs. Nov. 28, 1820. William Kendrick, of Birmingham, chemist, for a combination of apparatus for extracting a tanning matter from bark and other sub- stances containing such tanning matter. Dec. 5. Thomas Dobbs, of Smallbrook-street, for a mode of uniting toge- ther, or plating, tin upon lead. Dec. 9. John Moore, Jun, of Castle-street, Bristol, for a certain machine or machinery, which may be worked by steam, by water, or by gas, as a moving power. Dec. 9. George Vaughan, of Sheffield, for a blowing machine, on a new construction, for the fusing and heating of metals, smelting of ores, and supplying blast for various other purposes. Dec. 14. William Mallet, of Marlborough-street, Dublin, for improvements on locks, applicable to doors, and'to other purposes. Dec. 14. Andrew Timbrell, of the Old South-Sea House, London, for an improvement of the rudder and steerage of a ship or vessel. Dec. 22. Sir William Congreve, Bart. of Cecil-street, Strand, for improve- ments in printing in one, two, or more colours. Dec. 22. William Pritchard, of Leeds, for improvements in an apparatus to save fuel, and for the more economical consumption of smoke in shut- ting fire-doors and air-flues in steam-engine boilers, drying-pans, and ~ brewing-pans, other fire-doors and air-flues. Dec. 22. Marc Isambard Brunel, of Chelsea, for a pocket copying-press, and also improvements on-copying-presses.. Dec. 22. ' 156 Col. Beaufoy’s Astronomical, Magnetical, [Fes. abetiite 4 Sick sew ArTICLE XIX. Astronomical, Magnetical, and Meteorological Observations. . By Col. Beaufoy, F.R.S. Bushey Heath, near Stanmore. Latitude 51° 37/ 44-3” North. Longitude West in time 1’ 20°93”. Astronomical Observations. . Dec. 2. Emersion of Jupiter’s second aut 7h 32’ 02” Mean Time at Bushey. 7 33 23 Mean Time at Greenwich. Magnetical Observations, 1820. — Variation West. Morning Observ. Noon Observ. Evening Observ. Month. Hour. Variation. Hour. Variation. Hour. Variation. Dec. 1] 8h 50’| 24° 32’ 24/| 1h Q0/| Q40 36’ 44” 2| 8 45/24'35 341 1 15/124 36 25) Bh ee me ee oe 1 80194 SE 48 z 4} 8 35/24 31 40] 1 20/24 37 26) € 5| 8 40 | 24 32 26/ 1 25/24 36 45) § 6} 8 55/24 33 56] 1 40) 24 37 4] 1| 8 40/24 32 18] .1 20|24 36 42 4 8) .—|— — —|/— —|— — —| 8 9| 8 40) 24 33 19|] I 10} 24 36 22) 3% 10{/ 8 35/24 32 51] 1 15/24 37-21 5 ll} 8 45| 24 39 35| 1 40|24 39 49| & 12] | ee es | 20-] 24 86 20 ° 13| 8 45|24 35 15| 1 25|24 36 46 2 14) 8 45/24 32 27] 1 15) 24 36 59] for: @ S35 et Secae eo oe B 16] 8 40| 24 32 87| 1 10|24 87 00 f Mij}— —|— — —] ft 2/2 35 38)" & BS bs caddie ee adel | pepe bm fh et aati “hep S 19} —- —|/— — —|— -—|——-| 8 20 a | ee eT Bees Oe TS 21/ 8 50/24 33 30| Ll 25/24 36 24 * 22; 8 45| 24 32 12] 1 15 |24 87 46 8 23| 8 50/24 32 20| 1 10/24 36 19| £ 245 8 45/24 81 53| 1 15/24 35 58| 8 25} &$ 40/24 -31 56/ 1 20|24 36 17 be 26 & 55/24 32 29/ 1 25/124 36 05| Sf 27; 8 55/24 32 44/ 1 20/24 36 18 g 28| 8 45/24 32 84] 1 15 | 24 36 42 29} 8 45} 24 31 17] L 20/24 36 37 a 80} 8 50| 24 32 50| 1.20/24 35 BI co) 31} 8 45|24 32 10] 1 15/|24 $5 55 Mean for -oomete bs 45| 24 33 03| 1 20] 24 36 34 1821.] and Meteorological Observations. 157 Meteorological Observations. Month. | Time. | Barom. | Ther.| Hyg. | Wind. | Velocity. |Weather.| Six’s. Dec. Inches. Feet. . \Morn....| 29°676 | 35° | 78° | WNW Cloudy 33% if Noon....| 29°649 | 41 | 70 Ww Cloudy | 41 Even....) — — — — oT 36 Morn... .| 29°449 | 37 80 W byS Cloudy 24 |Noon,...| 29°449 | 40 69 Ww Cloudy 40% Even....) — — — — — ‘ 34 Morn....} 29-603 | — 82 SSW Fog, rain 34 |Noon....| 29-579 A3 75 |SW by W ain 43 Even....) — — — — — ‘ 49 Morn....| 29°479 | 49 78 | WbyN Cloudy 45 |Noon....| 29°483 | 52 72 W byS Fine 53 Even....| — sie — — —- 48 Morn....| 29-440 | 49 71 Ww Cloudy 54 |Noon....| 29°382 50 70 Ww Rain 51 Even....) — at ites — sae AB Morn....| 29°541 45 84 E Fog 64 |Noon....| 29°574 | 46 79 SE Rain, fog} 50 Even... ee — AF — — ve A5 Morn....| 29°563 | 49 79 Ww Fine ‘ T4 |Noon....} 29°589 | 52 73 W byS Cloudy 49 Eiven....) — — — = — 53 Morn... .| 29°682 | — TA W byS Cloudy ‘ < 84 |Noon....) — — — — — 50 Even ....| — _ — — — Aba Morn. ...| 29°703 | 47 69 W by S Cloudy 94 |Noon....| 29°660 | 48 68 | WbyS Cloudy Ase Even....) — noe “om — — Mom....| 29°542 | 48 | 74 |SW by W Cloudy ‘ ae 10, |Noon....| 29515 | 49 | 78 |SW by W Rain 51z Even....) — —_—)j— — — ‘ 48 Morn... .} 29°375 |: 49 82 WSW Rain My Noon....| 29-412 | 51 72 Ww Mizzle 514 Even eee@ar — — mere —— be 23 . AT Morn... .} 29°131 — 87 SSW Fog, rain in| Noon....| 29100 | 50 | 76 | WSW Cloudy | 518 Even....) — — — — — ‘ AG Morn....| 28932 | 46 | 82 NNE Fog, rain is} Noon....| 28990 | 36 | 82 NE Rain 364. Even....)) — — _— — — ‘ 30 4 Morn....| 29°396 | 31 70 NbyE Clear Noon....| 29°429 | 36 67 NNE Clear 364 Even....) — _ _ _ — 302 Morn... .| 29°464 | 32 65 ESE Cloudy ‘ 3 152"INoon....| — — _ _— _ 32% Even....) — — — — — 96 Morn... .} 297193 28 TA ESE Cloudy ‘ 1) Noon,...| 29°093 | 31 | 71 ESE Cloudy | 34 Even ...) — — —_ —_ — 30 Morn... .} 29°127 | 34 83 Calm Fog ‘ 172 \Noon....| 29194 | 38 | 78 | NbyW Fog 40 yen ....|- — — —_ — _— 36 Morn....}| 29°600 | — 87 SE by E Fog ‘ is} Noon....| 29°624 | — 83 E Fog 45 Even.... — a= one — om 158 Col. Beaufoy’s' Meteorological Observations. [Frn. Month. | Time. {| Barom. | Ther.| Hyg. | Wind. | Velocity. | Weather.| Six’s. Dec. Inches. Feet. f}Morn..../ 29°751 | — 889 Ss Fog, rain} 42 wo} Noon....} 29°788 | — 85 SW Fog, rain} 48% Even...:|° — — oe _ - 39 IMorn....| 29°900 | — 84 SSE Wet, fog 20} Noon....| 25°855 | 43 88 “S$ Fog, rain} 482 Even eeee EY or: bres 9 vere ‘ — 42 Morn... .| 29°618 | 47 73 Ww Cloudy ‘ af Noon....| 29°638 | 46 68 WwW Cloudy 48 Even . . —_— bea be a — — 364 Morn....| 29°688 | 37 78 | Wby N Very fine ait Noon... .| 29°643 | 42 72 WwW {Rain | 424 Even....| — —_ on _ ~ 31 iMorn....| 29°510°|".39 | 75 | ONE Cloudy |¢ 378 oat Noon....| 29°458 | 41 68 NE Cloudy Al Even . ee ne ee = band 314 Morn....| 29°400 | 32 13 E by N Cloudy ‘ 244 |Noon....| 29390 | 82 | 70 | ENE Cloudy |° 32 mven,...| — em past —e _ 28 iMorn....| 29°349 | 29 70 ENE Cloudy at Noon... .| 29°335 29 71 ENE Cloudy 294 Even. « —_ gl ba i aml = 26 Morn... .| 29°263 28 12 E Rain. 26) Noon... .| 25°263 29 70 | E Cloudy 30 ven... ..}- _ _ _ — 72 (Morn... .| 29°394 | 28 69 Eby N \Cloudy, ‘ 7 an) Noon... .| 29°402 | 29 69 E Cloudy 30 Even. e. arn ba, 4 i rey = oT | Morn....| 29404 | 27 | 69 | NEbyE Clear ‘ 28 |Noon,...| 29484 | 29 63 | NE by E. \Cloudy 293 Mom...,| 99-479 | 24 | 66 | NED: ady |¢ 238 Om...-. y ». \Cloudy 204 Noon,...| 29°433 | 24 66 | NE by Cloudy 25 ‘Even . am, _— — was _ 233 Morn....| 29°410 | 24 | 68 NE [Cloudy ‘ 302 |Noon....| 29°429 | 25 65 NE Fine 26 Even,...| - — _ _— _ 20 orn....| 29°432 | @1 10 NE Cloudy ‘ 31 oon....| 29°391 | 27 65 NE Very fine 272 Even. — _ anne _— al Rain, by the pluviameter, between noon the Ist of Dec. and noon the lst of Jan. 1468 inch. Evaporation, during the same period, 1-133 in. 1821.] Mr. Howard’s Meteorological Table. 159 ARTICLE XX. METEOROLOGICAL TABLE. eee io La BAROMETER,| THERMOMETER, Hygr. at 1820. Wind. | Max.| Min.| Max. | Min. | Evap. |Rain.| 9 a.m. 12thMon. Dec. 1;N W/{30°17/29°99| 42 $7 —_ j— 90 QIN © W)30°10/29°95} 42 31 — 03 84 31S. W({30*10/29°97| 50 38 — 90 4|. W_ |29°97|29:93) 53 37 nr 77 1|@ 5| W_ |30°03/29°87| 51 Ad — 06, 69 6| E_ |30:03/30°:02) 51 4.4, ~- 04 94 7IN W/)30°12/30°02) 55 49 — 82 SiS W/{30:15/30-12) 50 A5 — 76 9} W_ |30°15|30°05| 50 AT ee 64 10/S W/\30°05/29'90| 52 50 — j— 86 11} W_ |29:90/29°65} 53 48 — 25) 74 |¢€ 12iS W/29:65|29'49; 54 47 — |— 90 13,N W/{29-90|29'47| 46 29 wo 78| 94 14IN — E}29°98)29°90} 39 30 oo 84 15S = E}29°90|29°79| 34 26 — 62 16'S = E/29°79|29:73| 35 30 — | ae 78 17/ E = |30°10|29°73} 41 34 a 40; Ol 18} E |30°23/30'10| 57 41 567 02) 94 1@ 19} S_ |30°35130:23} 50 36 mom: ft eer | 100 20| S_ |30°35!30°11} 50 40 — 05; 100 21) W_ |30°15|30°09| 50 33 — 71 225 W{30°09/3001| 43 34 —_ 04 88 23} N_ |30:01|29°95|. 42 33 — P— 90 241N. E}29°95|29:93).. 35 30 oe 64 25|N E/29-93/29°88| 32 27 — 67 26 E |29°96/29:88| 32 29 — 70. +) 27, E — |29°99|29-96| > 33 28 — 65 28} E |30°04/29'99|} 33 eS _ 6 1 29° E |30°04/30°03) 29 Q4 —_ ae) 30, E _|30'03/30-02| 29 | 22 — | me 31.N — E}30°02/29°97| 30 Q1 Ad 58 30°35|29-471 57 | 21 | 1:01 | 1°67:100—58 The observations in each line of the table ‘apply toa period of twe' r hours, beginning at 9 A.M. on the day indicated in the first column. A dash denotes that the result is included in the next following observation. 160 Mr. Howard’s Meteorological Journal, [Fes. 1821. REMARKS. Twelfth Month.—1, 2. Cloudy. 3. Cloudy: windy night. 4. Fine. 5. Cloudy. 6—9. Cloudy. 10. Overcast: some rain. 11. Overcast. 12. Cloudy: rainy night. 13. Showers, with gusts of wind most of the day: some sleet at one, p.m. : about half-past eight, p.m. a lunar corona surrounded by a double-cploured halo. 14. Fine. 15. Windy: bleak. 16. Rain: sleet: snow: boisterous. 17. Gloomy : ground covered with snow in the morning. 18. Gloomy: the snow nearly all gone. 19. Foggy night: a faint lunar halo, of the largest diameter, about eight, p.m. 20. Gloomy. 21. Gloomy: foggy. 22. Foggy morning: cloudy. 23.: Overcast : drizzling. 24. Bleak. 25. Cloudy: bleak. 26, 27. Bleak and cloudy. 28. Fine. Gear morning: very cold wind. 29, 30. Cloudy: very cold and boisterous wind. 31. Overcast: cold wind. | | _ RESULTS. | ig te ¥ Winds: N; 1; NE,.4; E, 8; SE, 2; 8,2; SW,5;:W,5; NW, 4. Barometer: Mean height For the MONE. «00s coveesaccees eeeeeeeeveae eeeee eee 29-983 inches. For the lunar period, ending the 27th....4...4264.-+- 30002 For 13 days, ending the 12th (moon south) .......... 29-990 For 14 days, ending the 26th (moon north) ........... 29/981 Thermometer: Mean height ) LOOCR For the month, 2.45.5: /0\.. 08 t's 000% Bandanas. .! 39°241° For the lunar period,..... bassonds covececceccecccese A0°645 For 29 days, the gun in Capticocrips dsb repie@in eee i ~ 42482 Eivaporation. . escccione rs . BERD RE ap a teary Se 1-01 in. Rain. ..... soevecadccccseneseocescn joceVences ae seesiss cece ins asee SOT Mean of hygrometer. seveirtlales tintin tae Nevada same sGimh : 78° Laboratory, Stratford, First Month, 16, 1821. Ri HOWARD. - ANNALS OF - PHILOSOPHY. MARCH, 1821. ARTICLE I, On the Action of Crystallized Bodies on Homogeneous Light, and on the Causes of the Deviation from Newton’s Scale in the Lints which many of them develope on Exposure to a polarised Ray. By J. F. W. Herschel, Esq. FRS. Lond. and Edin. (With a Plate.) ' . (Concluded from p. 132.) Our equation (5) gives room for a remark of some conse- uence, as it affords a striking verification of the theory here elivered. . It will be observed that this equation does not involve ¢, and in consequence, the angle @ determined from it, at which the coincidence takes place, is the same for all values of #, or for all thicknesses of the plate. The observations of the tints in the tables given above afford us ample means of putting this remarkable consequence to the test of experiment. In fact, in the three series of tints observed in sulphate of baryta, the apparent angles between the axes for the mean red rays ‘are eae tie 62° 0’, 62° 2’, and 61° 53’, the mean of which is 61° 58’, while the apparent angles between the virtual poles in the same series are 72° 46’, 72° 36’, and 72° 47’. The semi- excesses of the latter angles over the mean value of the former are the apparent angular distances of the virtual poles from the axes of mean redrays, and are respectively 5° 24’, 5° 19’, 5° 25’, neither of which differs more than 4’ from the mean. To ascertain the real value of 6, we have only to compute the angles of refraction. In the specimen employed, I found 1°6475 for the index of ordinary refraction, and the angles of incidence New Series, vou. 1. | L 162 Mr. Herschel on the Action of [Marcn, (the halves of the above angles) being 30° 59’, and 36° 23’, 36° 18’, 36° 24’; the corresponding angles of refraction are 18° 12’ 30” (= a), 21° 6’ 10”, 21° 3’ 40”, 21° 6’ 40”; and since 6 = ¢ — a in this case, we find for the values of 6, 2° 53’ 40”, 2° 51’ 10”, 2 54’ 10”, the mean of which gives 2° 53’ 0” for the real angular distance of the virtual pole from the axis of mean red rays in sulphate of baryta. | Again, in the series of tints, Tables V, VI, VII, for Rochelle salt, the apparent angular distances of the mean red axis from the virtual pole were 277° 8’ — 257° 35’ =.19° 33’; 281° 30° — 262° 0’'= 19% 30’, and 282°’ 0% — 262° 25% =: 19° 36’, of which neither differs more than 3’ from the mean 19° 337, | Dr. Brewster (Phil. Trans. 1814, p. 216) has stated the refractive index of this salt at-l-515; but this is certainly a little too large. In four experiments made at distant intervals of time, and by different modes of observation, I have found 1-49640 1-50220 149670 | ~ 1:49853 for the index for the mean yellow-green rays, of which determi- nations the last is to be preferred, having been made with great care. The same experiment gave 1:49293 for the index for mean red rays. The apparent angular distance of the axis for ted rays from the perpendicular was 16°, which leaves: 3° 33” for the angular distance ‘of the virtual pole from the perpendi- eular. These angles of mcidence correspond to the respective angles of refraction 10° 38’ 20” and 2° 22’ 40”, of which the sum 13° |’ is the real angle‘between the virtual pole and mean red axis in Rechelle salt. The series in Table IV. gives 13° 2’ 25” for the value of 6, which agrees, completely with the fore- going determination. | ! | Lge baie I took seven plates of nitre of various thicknesses, and cut from different crystals, and by a mode of observation to be deseribed hereafter, found as follows : 2 Kh Tagsne VIII. Designation Mean distance of the virtual] Excess f ‘ ; tive of the plate,{Ples from the axis.of meanjabove the Order/of the coincidences, rae ellow rays (apparent), / mean, ; oe 1 1° 50” —A' |Between the fourth minimum and -) fifth maximum | 2 } 51 } —8 | |Alittle beyond thethird maximum. 2 hb 57 +3 . |Different at the twoextremities © 4 158 ' 0 \Second maximum 5 1 55 » +2 > |Seeond minimum | es L 59, +56 Ninth mininum 7 1 53 - 2 4 little beyond the eighth mini- mum hy Mean 1 53 . 1821.]° Crystallized Bodies on Homogeneous Light. 163 Although’ the constancy of the position of the virtual pole for different thicknesses is sufficiently made out here, the small differences which exist are certainly not attributable to errors of observation, which,. inthe method | employed, are usually con- fined: within much narrower limits. They are due to minute irregularities in the crystals themselves, consisting probably in a state of imperfect equilibrium of the molecular forces of aggre- ation, to which this salt is so’subject, that it is rather rare to nd a specimen in which’ the rings beyond both poles have exactly the same breadth or tints. , IV. Of the Tints developed by Crystals with two Axes out of the principal Section. ! If we place a crystallized plate at an azimuth zero in a tourma- line apparatus, having ‘the axes of the tourmalines at right angles, we shall observe, if its thickness be at all considerable, that’ the two oval spots om either side the axis of symmetry (which is now perfectly black) instead of being exactly regular in their figure, as.m Pl. TV. fig. 2, and tinged with colours symme- trically disposed on either side of a line m n perpendicular to the principal section, are invariably coloured at one extremity ¢ with a strong prismatic red hue, and drawn out at the other ® into more or less‘elongated and tapering spectra or tails_of blue and violet light.. The extremities r, r of the rings too have a large excess of ‘the red rays, and the opposite v, v of the violet rays. In crystals of the first class above described, the red extremity is turned towards the other pole, while in those of the second it is directed from it. If we subject a plate of Rochellé salt to this examination, the ovals a, a, are drawn out to a‘sur- prising length, and the whole prismatic spectrum is displayed in them with great vividness of colour, while the violet portions of the rings aregreatly elongated also, and appear to run into one another. Ifthe plate be turned round in azimuth, the phenomena assume the most singular appearances.of distortion ;, and as the rotation approaches to 45°, the, rings in the vicinity of the pole are gradually obliterated by their mutual overlapping, which is the greater the thicker the plate.. In all situations, however, the interposition of a red or dark green glass immediately restores the perfect symmetry and regularity of the rings, which are then seen in much greater number, and completely ,well defined. All this is the necessary consequence of the want of coinci- dence:of the axes: for diferent: colours: The lateral spots) for example, are formed for each homogeneous colour with perfect regularity close to. their. corresponding, pole;,.and. regularly ~decreasing in size from the red’to the violet... Theirarrangement will, therefore, be as’ represented in fig. 3, R, O, Y, &c. being _the poles.covresponding to the several colours, red,.. orange, &c. The oval spots composed of red rays being represented by 7; 7, those of the other colours will be super-imposed on them in their L2 ‘ 164 »\) | Mx. Herschel on the Action of ....., [Marcu, order, ovenapping, ‘8? represented by the dotted ovals oo, yy, &c. like the circular coloured images of the sun in the spectrum of an ordinary prism, giving rise to the long prismatic tails above described. Similar considerations will apply to the anomalous appearances presented by the rings of all the other orders, and in every situation. This suggests a very simple and pleasing experiment, which affords an ocular demonstration of the adequacy of the explana- tion I have advanced. Leta plate of Rochelle salt be placed in a tourmaline apparatus in any azimuth (45° is the most conve- nient) and firmly fixed on a proper stand in a dark room. The eye being now applied, let an assistant illuminate the emeried glass or lens of short focus * which disperses the light previous to its incidence on the first tourmaline, with the several colours of the prismatric spectrum in succession, beginning with the red, ‘The rings will then be seen formed successively of each of the colours, perfectly regular in their figure, but contracting rapidly in dimension as they become illuminated with the more refran- gible rays.+ At the same time the pole about which they form will be seen to move regularly in the direction of the other axis of the crystal, and if we pass alternately from a red to a violet illumination, will shift its position sh ie BR backwards and forwards, through a very considerable angle. If rays of two colours be thrown at once on the apparatus, their two correspond- ing sets of rings will be seen at once, crossing, but not obliterat- ing one another, and the distance between their respective centres wiil be observed to increase with the difference of their colours. | By measuring the interval occupied by the projections of the centres of the last visible red and violet rings, as well as those of the intermediate colours, on a screen at a known dist- ance seen with the other eye, I found the following values of the apparent and real separation of the several coloured axes : Between Apparent interval. Real interval. Red and orange. .... 0° 37’ very uncertain.... 0° 25’ ' * yellow. .... 1 50 rather uncertain .. 1 13 green ....4. 9 45) ditto. ws. ee eeciee 2 OY DOG. osc so i Or. oO! en ce shemed trams Gt oO THOIEO's o's: Ot, EEG cscs tbewssetns 0 ae VIONEE Snip oes DSO vilnncedessesae ce Gi, Ob As a mode of measurement this method is very inaccurate, A * See the description of an apparatus of this kind, subjoined. + See Lectiones Optice, lib. ii. Pars. i. Obs. xiii. from which the idea of this expe- riment is taken. ‘‘ Magn4que voluptate perfusus,”’ says Newton, with the enthusiasm of the true philosopher who loyes the field he labours in, ‘‘ videbam eos dilatare aut contrahere se gradatim pro eo ac color luminis immutabatur.” It is impossible to wit- ness the very beautiful phenomenon described in the text without entering into the same train of feeling. ; Be 7) 1821.] Crystallized Bodies on Homogeneous Light. 165 “especially in the extreme red and violet rays, both of which “would be copiously, and indeed almost entirely absorbed in ‘their passage through two plates of tourmaline of a yellowish- “green colour. Much more exact and unexceptionable measures will be presently given, but these are quite sufficient to establish the reality of the phenomenon described. | V. Of a secondary Cause of the Deviation of Tints, subsisting in certain Crystals, and of the anomalous Tints of the Apophyllite. To determine the dispersive power of any medium, and obtain some rough knowledge of its law, we make a prism of it act in “opposition to one of a standard substance. ‘To ascertain the total dispersion of the axes of a crystal, or the angle by which the extreme red and violet axes differ, we may make it act against itself. Since the violet rings are more elevated b refraction than the red, from the situation in which they would ‘appear to an eye immersed in the medium, a plate may be con- ‘ceived cut in such a direction as to make their apparent centres ‘coincide, in which case ‘the tints immediately about the poles ‘will coincide with Newton’s scale, and the extraordinary image ‘will totally disappear in the pole at an azimuth 45°, This condi- tion gives § ='0, 0 — 8a + 2 ¢ = 0, whence (supposing R, R’ the indices of refraction for extreme red and violet rays, and §R ‘== R’ — R) we find sR ta =do=—-— . tan. p The angle ¢ however becomes imaginary, and this method, in consequence, inapplicable when the separation of the extreme axes (3 a) is greater than the maximum dispersion of the colours of an intromitted white ray, that is, when | sR | ae a Let us resume our equation (6), and supposing the form of the function , and the constants a, k, k’, R and 3-R ascertained, let the angle 6, at which the coincidence takes place be observed, and the value of 3 a will then become known. If we suppose it small, which it is in the generality of crystals, we get oa > bi Bi igehs Brivis oe anaes By AOR AL a be. 3p sin. gb + Set Fh ) a ast dy av ; (c av @aé (} being put for J (6, ”) for the sake of brevity). At tiotdentes nearly perpendicular, 8 ¢ may be neglected, and the expression reduces itself to | 3 k— k’ y ta= ye ‘ia a (d) _ The comparison of these formule with observation, which o ae -166 » Mr. Herschel on.the Action of. [Marcn, will lead to some very remarkable consequences, requires_us.to know: the form of the function } and the values of k, k’. We will begin with the former,. and ‘in this investigation the -first step is to determine the general. equation of the isochromatic lines. In order to this, we must separate in.all cases. the law of the tint from that of its intensity. The latter depends entir on the greater or less facility which the emergent ray finds in )penetrating the prism of Iceland: spar employed for its analysis, -and. will not enter into. the present investigation. When) we examine a crystallized plate in a convenient graduated apparatus between tourmaline biotes crossed: at right angles, turning it slowly round between. them in. its. own, plane, the form of the coloured bands, if. illuminated with .homogeneous. light, :will remain perfectly unchanged during the rotation, but the two _black hyperbolic branches passing through the poles. will oblite- rate in succession every part of their periphery ; and the space over which the darkness extends, as well i By tale sillu- ‘mination of what remains visible, varying:at every. instant, give rise to so great a variety of appearances, that. some little _attention is required to recognize this perfect identity of figure. When the tourmaline next the eye is made to revolve, the crys- tallized plate remaining fixed, the complicated changes which take place, are perfectly reconcilable with the superposition of the primary on its opuileabrary set of rings, the relative inten- sities of the two sets at any point being regulated by laws, we have no occasion to.‘consider-at present, but the figure of the isochromatic lines, where visible, remains absolutely unchanged by ‘any rotation in this part of the apparatus. | “To form a first hypothesis on the nature of the function which ‘determines the equation of any one of these curves, we must select a crystal, where the proximity of the axes and intensity of the polarising forces are. suchas to bring the whole system of rings within a very small-angular‘compass ; as by this means we avoid almost entirely the disturbing effect of the-variation in thickness, arising from obliquity of mcidence, | Dr. Brewster;dn his’ paper of 1818,:has chosen nitre, as affording the best gene- rab view of the phenomena, andiit is admirably adapted for this purpose ; the whole system of rmgs being comprised'at a very moderate thiekness: within a space:of 10°, allowing-us to regard their projection on a coe perpendicular to the optic axis.as a true representation of their’ figure,undistorted by refraction at the surface, &c. If we examine the rings in this crystal (illumi- nated with homogeneous light, or by the intervention of a red glass in common day-light), itwill,be evident that the general form of any one of them is a re-entering symmetrical oval, which no straight line can eut in more than-four points, and which, by a variation of some constantiparameter, is in one state wholly concave, as 1, fig.14, them becomes flattened, as 2; then aoquires a minimum ordinate and points of contrary flexure;as 3 ; ‘1821.] Crystallized Boilies»on Homogeneous Light. 167 then anode, as‘4; after which it:‘separates imto two conjugate “ovals, as‘5:; which ultimately contract themselves into thepoles P, P’ as conjugate points. The general idea ‘bears a strikin resemblance to the variation in form of the curve of the fourt order, so well known to.geometers under the name of the lem- niscate, whoseequation is (x? + a + a’)? = a? (6? + 4 a) when ‘the parameter'd gradually diminishes from infinity: to:zero, 2 a being the constant distance between the poles. In order, however, to put this to a satisfactory examination, accurate measures must be:taken, ‘which, in the case of nitre, from the minuteness of the system of rings, presented at first some diffi- culties. ..These I obviated, after many fruitless.trials, by a mode of observation which I have found extremely convenient and accurate, and which applies particularly well to the present pur- pose. it consists in projecting the rings ‘by solar light on a screen ina darkened room, by which»means they may be magni- ‘fied to any required extent, examined at perfect leisure, and in eall.their phases, ;and «measured or traced with a,pencil with the sutmost:exactness and facility. They may be thus:exhibited too ‘to.a number :of spectators at once; a thing which may prove aserviceable to the lecturer, for which reason Ihave subjoined to ‘this paper a brief description. of the apparatus I-employ. ; Having cut avery perfect.crystal of nitre at. right angles. to.its saxis of crystallization, and adjusted it properly on this apparatus, ‘the rings were projected .on a large sheet of paper, stretched, »while. moist, .on.a drawing board, by which means it assumes a truly plane:surface by the-contraction it undergoes while drying. ‘The poles were then marked, and the loci of the successive -maxima.for red:rays carefully outlined. The screen being then wemoved, aseries of lemniscates were laid down by points, hay- ing ‘the same poles, and, one common point in each, chosen where the tint was most decided. tis unnecessary to. give any «comparative statement of measures in the observed and con- “structed: curves, as the points, .graphically.laid.down, uniformly fell on the pencilled. outlines, or, in the few instances to the con- dary, within limits less:than the very trifling irregularities of the uthnes, themselves. me if a The graphical construction of these curves is rendered extremely easy by the elegant .and well-known property of the lemniscate, in which the rectangle under two lines drawn from ‘the foci (or poles) to any point in ‘the periphery, ‘is invariable throughout the whole extent of the curve. ‘This is-easily shown ‘from its equation, and the.value of this.coustant rectangle in any one curve is expressed by a 0. 7 ) We must.next,enquire how the.constant parameter 0 varies.in passing from ring to ring. To this end I projected the rings, illuminated by red light only, on a screen as before, and having 168 | Mr. Herschel on the Action of.» [Marcn, outlined the successive loci of the minima of illumination, and laid down the poles, found the values of a 6 in the several lem- niscates, as in the following table : | m0 | " Values ofabcom-|Excess of com- Order of the mi-|Observed veined : puted from for-|puted above ob- ; of a 6 in square} Differences. 7. s al nimum. ji ches. mula ab = 1-59lserved values of ; x fh. * a b n= O 0°00 0-00 0°00 1 1:62 1°62 1°59 —0°03 2 3-165 1°545 3-18 + 0-02 Ss ‘4°69 1-525 ATT +0°08 4 6°27 | 1:58 6°36 +0°09 5 7:87 1:60 7-95 +0:08 6 9°56 1-69 . 9°54 —0-02 rj 11-09 1:53 11°13 +0°04 8 12°77 1:68 197 —0-05 er 14:33 1:56 14°31 —0-02 10 15-93 1:60 15°90 —0:03 Mean 1°59 The nature of the illumination not allowing: the delineation to be performed with the same freedom and precision as in @ fuller ‘light, the values of a 6 in the second column are the means of a ‘great number of measures, taken in every part of their respective curves.. The numbers in the fifth column exhibit the excesses of ‘the terms of the arithmetical progression in the fourth (whose ‘common difference is 1°59, the mean of all the differences in the - third column) above the observed values of a 6, and are so small -as fully to authorize the conclusion, that these values, and of -course those of the parameter 6, increase in arithmetical pro- ‘gression with the order of the rings ; or, in other words, that the — ‘number of periods performed in a given space (= 1) by a lumi- nous molecule going to form any point M in the projection of ay ring is proportional to the rectangle of the distances P M, P’ M, of that point from the two poles. ‘Now, if we extend our views to crystals in which the distance - between the axes is considerable, we may reasonably expect that ‘ the usual transition which takes place in analytical formule from ‘the arc to its sine, when we pass from a plane to a spherical sur- face, will hold good. If this be the case, we shall have at once, and in all cases | fi Sal! Y (6, #) = sin. @. sin. # .and the nature of the isochromatic curve for the nth complete period will be expressed by the equation } : ; . a n , ” | sin. 9. sin.” = ~~. cos. ¢ = nh. cos. (e) putting A for . If the plate be cut at right angles to the optic axis 1821.) | Crystallized Bodies on Homogeneous Light. 169 ~ . eos. 6 + cos. 6! 2 . com'ar ‘ cos. = * ~ gin. @. sin. & = ST ea, (008: 9 + eit (ae (f) To put this to the trial, [ took a plate of mica, whose thickness> measured 0°023078 inch, and having adjusted it accurately on a divided apparatus, placed it in an azimuth 45°, and, by the inter- vention of the red glass above-mentioned, observed the maxima and minima of the extraordinary pencil between the poles. As these observations, when Sie seldom agreed unless within ‘a few minutes, 10 were taken of each maximum and minimum. ‘The angles of incidence, deduced from a mean of similar obser- “vations on each side of the perpendicular, are set down in the second column.of the following table, each number in which is, therefore, a mean result of 20 observations. The first column contains the values of m, or the order of the ring observed ; the and consequently ‘third, the angles of refraction, to obtain which [ used the index 1-500, employed by M. Biot.* The fourth and fifth columns contain the values of 6, 6’, thence computed, and the 6th, values in. @. sin. 6! of the coefficient h, deduced from the formula 4. = tee () TaBLe X.—Mica. Thickness = 0°023078 in. - Values |Angles of in- Angles of re- ;|Values of| Excesses. of n cidence. factin.| | Von . Iebrrciece write he _jabove mean. 0-0. [35° « 8’) $022°° 31%); 0") 0° . 0 . 045°. 2". 0” ! 0°5 32 55 20 21 14 40] 1 16 20 143. 45. 40 |0°032952}| —0-000195 10 |30 34 40/19 49 30)2 41 30 |42 20 30 |0-033622| + 0°000475 * 15 28 15 40|18 24 0/4 7 © {40 55 0 |9°033035|—0-000112 2:0 (25 34 20|16 43 30) 5 AT 30 139 14 30 |9°033327| + 0-000180 25 22 46 20 14 57.15 |7 33 45 |3T, 28 15 |0-033148| +0-000001 30 |19 35 40 |12 55 10|9 35 50/35 26 10 {0-033058|—0-000089 35 115 48 40 |10 27 50 |12 3 10/32 58 50 |9-033026|—0-00012L 40 |10 48 50/7 11 107115 19 50/29 42 10 }0-033010|—0-00013T 9°033147 ! _ The last column of this table exhibits the deviations in excess -or defect of the values of the quantity 4, so computed from the mean of all of them. Their smallness, in comparison with the . quantity itself, and their alternations of sign, are evident proofs * Recherches sur les Mouvemens des Molecules de la Lumiére, &c. p- 482. He takes . it equal to that of glass—“ ce qui ne doit pas étre fort éloigné de la verité.”” I have _ attempted, without success, to measure its value. , What has satisfied M. Biot and Dr. Brewster (for the latter has evidently used this index, or one very near it, Phil. Trans. . 1818, p. 230) ought to satisfy every one; yet it is fortunate that in the present instance, a slight variation in the refractive index will produce but a very trifling change in the relative values of h. ped 170 . Myr. Herschel on the Actionof °° [Manct, of the constancy of this»coefficient, and we are, therefore, autho- rized to take sin. 6 x sin. #’ asthe general value of 1 (6, ). The observations on Rochelle salt, presently to be:noticed, :confimm this law.* If we denote by / the minimum length of a double oscillation, or the space passed.over during one complete period by a ray transmitted at right angles.to both axes, we: have‘. +3 and consequently h. = -, l=ht. Ifwesubstitute forhand . #:their values above found, we obtain , 1 = 0-00076497 inch . for the minimum length ofa period performed by a mean red-ray in mica, - ‘Resuming our general equations (b),and (d) if we substitute 4the value mow determined for 4, and write 5 for we have Y..cos.¢!... sine. sin. = 1. cos. 9 .sin..(6 — 3a +4 89). «sin. (6' + 8a + 39); . ‘(xg swhence it is: easy to derive (independent of any approximation) cos. 2\(a + 0a) = cos.2 J +2 z ae . sin. 6.sin. (h) while our approximate equation (d) furnishes the following very convenient formula for incidences nearly perpendicular 1—U sin, 6. sin, 6" : t “sin, 2a ; () | The simplest supposition we can frame relative to the values of the constant elements /, /' is their proportionality ‘to those of ‘¢, c', or the lengths of the fits of easy reflection and transmission. This cannot certainly be’far'from the truth in crystals ~with one ‘axis, in which the coincidence of the tints, with those of New- ton’s:scale, is for the most part.exact. In sulphate: of lime too, and mica, the,only crystals with two axes which have been exa- mined with sufficient exactness, and under the proper circum- extraordinary ray in such crystals isigiven by the formula v? = V? + a. sin. # Fol- = that in crystals with two axes we should have v* get Cog mene J isi forests; and-have pu ly abstained from entering any “farther into the general laws" aouie efrhction’ polarisation ‘than I could possibly 1821.) Crystallized) Bodies on Homogeneous Light. ‘TAL stances: for ascertaining ‘this important point, ‘the:law of :ptopor- tionality seems tovbe sustained: with’great precision. This may seem to iauthorize'the general conclusion, ‘that in. all «cases, S = : ‘Let us see how this agrees with the méasures given in the former part of this paper. “fn sulphate of baryta, if we take Dr. Brewster’s measure of the dispersive power,* we'have § R.= 0:019, and consequently, calculating on the data determined m»p. 161, we must have, a the’ virtual pole, | . x g@ =:21°:5' 30" - : ot = 20° 60! 307. 8g Ht ‘Now, if we suppose / = 6°3463 ? = 3'9982, the values of é and c! respectively for the extreme red and violet. rays,}we shall find by substitution in our formula (h) - | ‘8a = 61! 10" 3 : Bat a red ray/penetrating the surface from within the :crystal-at an-angle-a-=- 18°12! 30",-anda violet one-at an-angle-a-+--d-a = 19° 3' 40", would emerge at.the respective angles 30° 59!.and 32° 58' 20", and would include between them an ‘angle of ‘1° 59" 20", which should be the apparent separation of the red and violet axes in the plate employed. Now, previous to the computation of this result, I had carefully measured this angle, ‘by observing the incidences at which the extreme red and violet rays of the prismatic spectrum, received on the reflector of a ‘graduated apparatus, respectively disappeared. from the extraor- dinary image at the poles P, P’. I thus found | Interval of the poles P, P’ for red rays ...... 62° .2’ © 3 : etsy: Ditto. for-violet. ........ 66 5 . Semi-difference, or apparent separation ‘of the ‘axes, 2° 1° 30%, whichodiffers’ from its computed value only by 2’ 10". We may, therefore, fairly ‘conclude, that in the case of sulphate of baryta, the. hypothesis 5 7 ~ does not deviate sensibly from the truth. - \If-we apply our formula (7) to' the measures above given’ for Rochelle: salt, ‘the result will be widely different. ‘The same supposition as to the values of /, /’ being made, ‘we get . | ba = 4° 2’ 50” ! The incidence. being. nearly perpendicular, and the angle.small, * we need. only increase it. im the, proportion 1:499.: 1, to have. the apparent. angle, which thus comes out 6°:4’. We haveialready found 9°46’ for the.same angle, by a method: which must neces- sarily give a result much. below the truth. This difference is, by far too great to arise from any errors of. observation ; but, to obtain more exact-measures, I took several times the apparent ~ *'3R = 0019. Treatise on new Philosophical Instruments. ‘+ Biot, Traité de Physique, vol. iv. 172 ... Mr. Herschel on the Action of». [Manrcn, angular separation of the axis of each colour from that of the extreme red: by the direct. homogeneous light of a sunbeam, separated by the prism, and received on the reflector ofa divided apparatus, when, after the proper reductions for refraction and dispersion, the results were as follow: ’ Sree ao 1 si! No. of «! Colour. jration of — Sq = | Values of 2 a, jobser- _ jaxes. vations, Extreme red .....csccesccceses 0° 0’. ‘45? 49! 13 Mean Ved. wrsivin Bs. ies. ae: i “ss Fe 13 38 A5 Mean orange... ‘ 2.37 1 44 72 14 18 Mean yellow. .......seceeeeeee 4 0 2 40 70 28 20 Mean green., .. 00s .ecccese cece 4 49. 3. 52 67 57 16 Medi WRG Ss cine dick ceeds svees 8.2 5, 2 65 0 13 Mean indigo ........++seeee0+ 10 Qi 6 54 61 54 33 Indigo violet...........seceees 11 17 7 31 60 40 2 Mean violet........ Of Span een 13.53 9 IT 57... 8 2 Extreme violet.......... ye ge 1S 23 10 14 55 14 8 Though the total separation of the red and violet axes in this table so far exceeds what we had before estimated it at, I am fully satisfied that it is no way exaggerated, but rather falls short of the truth, It is very practicable, by combinations of coloured lasses, liquids, &c. to insulate either extremity of the spectrum in. a state of the most absolute purity. In this climate, the dis- — persed light of the sky in the neighbourhood of the sun, which always mixes with the prismatic beam, is so considerable as to obliterate the feeble rays which compose the two extremities of the spectrum, and it 1s only by interposing such combinations between the: eye and the Iceland crystal used to analyze the olarised ray, that they can, be examined with any certainty. The combination [ employed for the extreme red was such that when the whole spectrum thrown on a white screen was viewed through it, it was seen reduced to a perfectly circular, well defined, deep red image, whose centre fell of the very furthest termination of the red as seen by the naked eye, and whose cir- ecumference attained, or perhaps surpassed the point where the maximum of the calorific rays has been supposed to be situated. In like manner, when the same spectrum was examined with the violet combination, a very slightly elongated violet image became perceptible, but every trace of the indigo, and the brighter por- tion of the violet rays, was extinguished. For observations on the indigo, and all the more refrangible portion, I employed similar artifices, without which I found it perfectly impracticable to obtain any regular and comparable results. ( a J . . ._ The coefficient = in our formula being the only part not immediately deduced from observation, it is evident that the assumption 4 ae must be widely erroneous in the present 1821.] Crystallized Bodies on Homogeneous Light. 173 instance, and it, therefore, becomes necessary to ascertain the - values of Z by direct measures. This is rendered, easy by the equation (¢) which gives : bas eo sin. 6 . sin. 6/ decid %. COS. 6 ~ | We have only, therefore, to observe the inclinations ofa plate of known thickness, properly cut and adjusted to 45° azimuth, which correspond to the alternate disappearances. of the. ordi- nary and extraordinary images, at which points the values of x are 1,2,2, 4, &c. ; computing then the values of 6, ’, and ¢,.and substituting, we get the values of /, without detailing particular experiments. The following table expresses the final result of a great numberof such measures : 5 Number § of Colour. Values of 7 in inches.| observa- ; tions. Extreme red ....:..... 0°0056158 64 WOM TOR. oc ecceacces 0:0050032 14 Mean orange .......... 0°0045852- 24 Mean yellow .......:.. 0:0040583 52 Mean green. .......... 0:0036549 _ 62 Mean blue. .....52.05 0-0032863 22 Mean indigo .........: 00029868 52 Extreme violet ........ 0:0025093 49 The.observations from which this table was calculated were made indiscriminately on the maxima and minima of all orders. Those of different. orders were of course computed separately, and found to agree without exception in giving the same values of / within limits of error less than those to which the observa- tions are liable; thus affording another proof of the exactness of the law of periodicity above employed... Now, if we compare these one with another, and with those of c as deduced by M. Biot from Newton’s observations, we shall have as follows : v|. Pa Colour. Values of - Values of — Extreme red ..,....... - 100000 | 1-00000. Mean red. ............| 0°89093 | 0°96215 Mean orange .... +... 0°81659 | 0:90490 Mean yellow ...,......| 0°72266 | 0°85550 Mean green ...... +..| 0°65082 0°79433 Mean blue....... eees-| 0°58520 0°T3725 ' Mean indigo .......... 0°53156 0°69641 Extreme violet ........ 0°44684 |. 0°63000 It appears from. this comparative statement, that the forces of _polarisation and. double refraction in the body now examined, act with much greater proportional energy on the more refrangi- -ble rays than in mica,'sulphate of:lime; and other similar bodies, 194 MP, Herschel on the Action of . [Marcn, and ‘consequently that, even were its-axes coincident, its tints, though perfectly regular, would still differ very sensibly from the colours of thin plates. This secondary cause of deviation ought to become sensible in plates. cut so .as\to contain both axes, if examined at a perpendicular incidence; but I have not yet had ai opportunity of making the trial. | , ; . Ifwercaleulate on the numbers above given, it will soon appear that’a perfect coincidence of all the colours in a single virtual polé is i ible: For this-purpose -wemay employ our equation (7) which easily affords’ the: following ce 8 cos, 2.(a.-+ 6); = cos. 2.4 $1 + —F. tan. 2.4. sim. (.— dia) ' _ C08. 2a . (cos, M)* taking M an auxiliary angle such that | tan. Mix “ 2.tan. 2a. — _ sin. (— da) whence the value of @ orthe position of the coincidence of any two coloured rays becomes known, the values. of /, /’,.and — 0a being given from the aes ore tables.. If we unite: the mean red with the mean green, these formule give 6= — 11° 29’, and if with the mean blue, 6= — 14° 8’) of which the one falls short of, and:the other exceeds the. angle»— 13° 1! given by observation. If we determine by SUE aT the values of / and, +.9.4; whichogive!é. = — 13°1,,we shall find very nearly = '34681 — da = 3°37! —ta pI = 4°Oy ‘which correspond to.a blue ray strongly inclining to green, and in the brightest part of the colour. Now it is evident that. when ‘a rigorous union. of all the rays in the proportion in which they exist in white light, is impossible, that of the strongest. and brightest colours in opposition to each other will at least.ensure the nearest. approach to a virtual pole ‘on the principles,above demonstrated, and a white will’ thus be produced, not indeed mathematically. perfect, but-containing.no-marked-excess of any of the more p»werful colours. The apophyllite is the only crystal with one axis whose tints exhibit a sensible deviation from the scale of Newton. Its phe- nomena, howeyver,,are entirely independent, of the first and prin- cipal cause whichvproduces: the deviation: im erystals with two axes, viz. the separation of the axes of panei 9 coloured rays, and are referable solely to the secondary and subordinate cause, of which Rochelle:salt! has just afforded aniexample, viz. a pecu- liarity in the law which regulates: the lengths of the minimum oscillations of the differently coloured rays within the medium. __-). The tints of the apophyllite commence at thecentre of the rings;-and increase in regular progression outwards, following the same order, whatever be the thickness ofthe plate: _ It follows: from this, thatthe multiplier M in-our general for- 182h.] | Crystallized, Bodies: on Homogeneous. Light. 175 mula (a) is the same for all the coloured rays, being zero at the commencementiof the scale; and hence it:follows, as a necessary consequence, that the axes of all the colours are united in one, and the virtual and actual poles cvincide with each other and with the centre. Did'any sensible separation: of the axes exist, it-must become perceptible by the ellipticity of the rings when examined with homogeneous light of that colour from which they are furthest asunder ;, but with the greatest attention, in lates: of considerable thickness, I have not been able to observe the slightest shifting of the axis, or deviation from. the -cireular figure, in passing from ared to a.violet illumination... Moreover; itisevident from the preceding’ theory, that-any difference which may exist in their position,, if too small to be sensible to the eye, can produce only an imperceptible deviation: of: tints: In fact; . if we suppose a = o for any colour, we get, for the position of | the virtual pole, ! FF EMER, ele fe RN sin. 6 = yf = _Sin...ord. § being the angular distance of the point of coincidence from the single axis of that colour: It is; consequently, msensible when 8a isso. Now, the polarising force of the apophyllite being very feeble, the diameters of the rings in any plate, of moderate thickness: must so far. exceed this: very minute quantity that the virtual poles, did any exist, must fall within the limit ofthe cen= tral blackness ; the Newtonian, scale would still appear. to,com+ mence-from. the. centre, nor could: any sensible:deviation from it arise from this cause. . Jando 2. When the prismatric spectrum.is passed over an apparatus containing a plate of this mineral; no perceptible change in the — magnitudes of the: rmgs for different colours takes place. Hence it appears that the value of the function / for all the coloured rays is nearly alike. By measures taken-on-a divided apparatus, a. slight difference is observed. Taking the mean’ refractive index R at 1°5431 (by a.very careful measure) and the dispersion & R at 0-017, the formula 8 oft / ah oA sin. §2. gave-as follows: Extremered....i.......] J = 0:0002066: Meam red. \.i+.b, coms.s oad 0:00928 10 Mean orange ........,.4 00092337 Mean yellow’... .. -eeeep ~~ 0009 1503 Mean greens 264 «sec. » 00090648 Mean. blite,..c0j-0 00s - 0:0092059: Mean indigo .......-..} 00093964 Extreme violet’ ....... 60160660?" bas ? errs tT _ This: table, though not given as exact, owing to.imperfections am the specimen: examined, agrees: with. the-succession of tmts, which, asfar as the fourth:order; were.as follows: |. 176 Mr. Herschel on the Action of» [Marcu; Apophyllite. Thickness = 0:0829 ineh. Inci- "|. Ordinary pencil Extraordinary. ry pencil. xtraordinary. O° 0’ Bright white... 2... 000 {/BIACK oc... cc cccccreccocccccsccs The axis 18 50 White, with a trace gee purple sa sb scticn ds ob. ite, slightly greenish | 21 50 retina pathen icles [Fuse tie cue eeecccecess(J6t max. of ilumination __ 25 12 |Pale greenish yellow ....|Purplish white 29 45 |White................../Sombre violet blue } 4 30.: 50. |\White.......... att dhl oi Extremely sombre violet...........|18t minimum 33 3 |White, with a strong tinge Of Violet... 2. os ce 5c ---|Pale yellow green 35 50 Blue, strongly inclining to} » ) | purple; 5 oes - és» .++++|Greenish white 8T 20 Sombre indigo, inclining to | violet...... ip eeeen a: White 33s 5 Sombre violet ers) 5 eR ee eesee ees cclee coe ceees o(2d Maximum 40 10 Tolerably good yellowgreen|Purplish white 43 55 |White,with a traceofyellow Obscure indigo, inclining to purple 44 27 White ap OBS eeS STO EY Rect secret Bayo wubae ey oeeceeeees (20 Minimum 46 45 e purple ..:...... -.+.|/Tolerably yellow green 49 ST Saoeaben sarcaio blue .:s..0. Yellowish white 50 30 |Sombre violet.......... oo] White i, oc ec core nccenceses es eee (Sd. maximum 53 40 (Green yellow....... -»-..|Pale purple 56 0 [Yellowish white..........|Sombre indigo blue ..............(3d minimum ° 56 40 |Yellowish white.,.......|Sombre violet White ...........+0+... |Livid grey | 59 35 |Pale purple ......... -.-.| Yellow green ag alt , 61 45 |Sombre indigo. .......... Pale yellowish white. ............./4thmaximum 62 10 |Sombre violet............|/ Yellowish white 63 0 /|Faint violet white........| White ; avid grey. oo. occ sscecss White 66 0 |Tolerably green yellow ...|Purple . 69 30 |Yellow white..........-. Very sombre indigo..............|4th minimum In the colours of thin plates and others of the like composition, the difference in the lengths of the periods of the different rays is so considerable, that after seven or eight alternations of colour, the rings confound one another, and are blended into a uniform whiteness. Were the periods more nearly equal, a greater num- ber of rings should be visible, and were they strictly so, the succession of alternate whiteness and blackness should be conti- nued to infinity. As the values of /, ’, &c. in the apophyllite approximate pretty closely to this limit, we should expect to see a much greater number of rings, ‘and this I find to be really the case. By inclosing a thick plate in balsam of “gots in a pro- per apparatus to increase the range of incidence, | have counted as far as the 35th order, when I desisted ; not from any want of alternate colours, but owing to their extreme closeness, which rendered it impossible to number them distinctly. Indeed I have no doubt that could a very thick and limpid specimen be procured, hundreds might be seen without artificial aid. In two instances then, at least, and probably in many more, i © 1821.] Crystallized Bodies on Homogeneous Light. 177 “or perhaps to a certain small degree in all cases, the minimum ‘lengths of the periods deviate ‘in their respective proportions from those of the fits of easy transmission and reflection ; a cir- ~cumstance which of itself is sufficient to prove the independence of the causes of these laws of periodicity. If we take Rr = R A, fig. 5, and construct a curve whose abscissas A P are the values of c, c’, &c. and ordinates those of /, /', &c. the straight line r o y g 67 v inclined at 45° to A R will Bi ean the locus ‘ for crystals, such as carbonate’ of lime, in which the periods fol- low the Newtonian law, 7’ 0’ y’ g’ b’ v’ v’ will represent the same locus for tartrate of soda and potash, while ; 7" 0" y" o" 6! a yl_is ‘the curve similarly traced for apophyllite. Having communicated to Dr. Brewster my observations on - the deviation of tints, and the conclusion I had thence deduced “as to the separation of the axes of the differently coloured rays, ~L received in answer a letter, from which, in justice to that inde- fatigable observer, I subjoin the following extracts : “MY DEAR SIR, Esk Hill, by Roslin Laswade, Sept. 18, 1819. ‘In consequence of having been some time from home, I ‘have only now received your letter, and hasten to reply to that part of it in which you request me to state what results I had obtained respecting the deviation of the’ tints from Newton’s scale. - The following general points will enable you to judge of _- the progress which I had made in the inquiry. ““ 1. In almost all crystals with two axes there is a deviation from the tints of Newton’s scale. | ' 2. This deviation is greater in some crystals than in others, ‘being a maximum: in acetate of lead and tartrate of potash and soda. «3. That all these crystals may be divided into two classes, ‘viz. those which have the red ends of the rings inwards and the blue ends outwards, and those which have the red ends outwards and the blue ends inwards. ; / “4, That in all crystals with two axes, the doubly refracting ‘force of one axis in-general acts differently upon the differently coloured rays from the doubly refracting force of the second axis “5. That as the polarising force is always proportional to the force of double refraction, the polarising force of one axis will act differently on the differently coloured rays from the polaris- ing force of the other axis. 6, % Her ae af * * % % Se _ “7, The consequence of this is, that there will be different resultant axes, or different points of compensation for the differ- ently coloured rays. | “8. All these effects may be calculated with the utmost accu- racy, if the ratio of the dispersive powers of the two extraordinary ~ New Series, vou, 1. M wg8 Mr, Hersehel.on the Actionof [Magon, _Tefractive forces is given, or vicewersd, the dispersive pow . be obtained from the angles of RUE eA ah path nb pd _Yiolet rays.ofthe spectrum. __ 7 vl _ 9, Thave found crystals.in,which these phenomena are deci- _dedly connected. with the .rotatory phenomena; and from. this ~highly important fact Iam led to conclude that beth,have the , Same origin, and that all the rotatory phenomena.are,, as I haye _ Stated.in my paper, the-result of the uncompensated tints of two axes, equal jor the mean yray, .but unequal for all the, rest. (Here follows an illustration by adiaphragm.) . a “10. The division, into two classes in sect. iii..as founded “merely on observation, .is converted into another.diyision into two classes; viz. 1. That in which the doubly refracting foree of the principal axis acts,more;powerfully onthe blue rays, than the other axis does; and_2. That in which it acts less powerfully. The first class comprehends those crystals.in which, the blueends ‘are inwards, and the second, those in which the.red.ends are ‘inwards, or nearer'the principal axis.” | In a subsequent letter (Oct. 4), he adds, “The virtual poles, which+you mention, I discovered: in the syear 1815, and I have two accounts of them in my Journal,:the one signed on the 24th January, 1816,;,and the other 6th Janu- vary, 1817, by Sir G. Mackenzie, President. of the Physical Class “of the Royal Society.” “No comments on the above extracts are necessary. -They establish at once the: priority.of Dr, Brewster's observations, and the independence of mine. With regard to the. division of erys- tals into two classes, which observation. has :alike suggested to both of.us, it is unnecessary, if we regard ,either.of;the :two ;classes as having the ,angle.between the resultant.axes greater ‘than a right angle. ‘In Dr. Brewster’s table, Phil. Trans. 1818, P. 230, succinic acid and sulphate of iron, are ,stated.as having ‘this angle 90°. if this determination corresponds,;as in.all pro- “bability it does, to the yellow rays, they belong,at once to both élasses, and are, in fact, instances of the limit,whereone.class. _passes,into, the other. Bicarbonate of ammonia, in which [vcan perceive no,separation ofthe axes of different.colours,,nor,,of course, any virtual poles, belongs in hike manner.to. both classes, or to. neither. | _Joun F.W.HeEerscuen. a: APPENDIX. ) : ‘Description of an Instrument employed in the foregoing Expert- ments onthe polarised Rings. Phe singular property possessed by the tourmaline, by which a plate of it of any moderate thickness cut, in a direction parallel ‘tots axis of double refraction, is enabled to Seen toetdbole at Whi wd 7 4821.) Crystallized Bodies on Homogeneous Light. PID jmearly ‘the whole, of an incident pencil polarised in a ‘plane parallel to that axis;*. was-pointed out by M. Biot,-in the fourth wolume.of his Traité de Physique, and he has availed himself of at with: his accustomed ingenuity, as affording an -extremel ready and convenient mode of viewing the phenomena of polari- sation, much moreso than by the use of plates of agate, prisms of Iceland spar, or a second reflection. ‘It follows, from the above-mentioned property, that if.a beam of ordinary light be aade to:traverse such a-plate, the whole of the emergent pencil, er neatly so, -will/be polarised in a-plane-at right angles to the axis; forthe incident ray: beimg divided by the doubly refracting ‘force’ into two pencils, polarised in planes, the one parallel, the other perpendicular-to the axis, the former is extinguished in its passage, while the latter,emerges with nearly its full intensity. — ' “Hence, if two such plates are crossed at right angles, though separately very transparent, their combination will -be opaque. ‘There is.a-great difference, however, in the degree in which tour- aalines. of different:colours possess:this power. Those of a light «green, pink,-or bluish colour, are quite improper, allowing a con- «siderable portion of light to pass when so crossed ; while, on the ether'hand, those whose colour verges strongly to the honey yellow, -or to the hair brown, or purplish brown, effect nearly a complete absorption, and -afford, when crossed, a combination. lmost impervious to light. In ignorance of this distinction, E sacrificed -several fine and valuable specimens ‘before I could obtain: proper plates. | ‘When. acrystallized lamina, cut ina proper direction, is inter- posed between such a combination of plates, it disturbs the ‘polarisation which the light has received in traversing the first late, and renders.a certain portion of it capable of traversin; -the:second: the.colour-and intensity of this portion, varying wit the direction of the ray, give rise to the phenomena of the pola- aised rings, which may accordingly be seen by applying the eye, and receiving onit the dispersed light of the clouds, ‘&e. 'In-order, however, to equalize as well as disperse ‘the light, which is of great importance to obtaining a perfect view of the “phenomena, an emeried glass maybe cemented on the anterior “plate, or the first surface of the plate itself roughened; but it wwill be found more convenient in practice to employ a double veonvex lens of short focus for this purpose, by which, if neces- ‘sary, a very strong illumination may be obtained, and an extremely minute portion of a-erystal subjected to examination. ** The same property is observable in the.epidote, the axinite, and all other natural and artificial crystals which exhibit any degree of dichroism when examined by wnpola- vised light. Muriate of palladium and potash possesses it in the highest perfection. “This remarkable effect is easily explained by a reference to the general principles laid “down by Dr? Brewster in his papér on absorption, Phil. Trans, 1819, p. 11. ‘The inci- “dent pencil is separated by the doubly refractive force into two, oppositely polarised, one - -of-which is partly absorbed, the other emerges (polarised in its proper plane) of nearly its original intensity. | M 2 180 . | Mr.,Herschel.on: the Action of + [Maren, I have thus occasionally examined the rings in a portion not exceeding the. hundredth ..of an inch in: diameter, and. thus ‘detected irregularities of crystallization of a very singular nature, -In. many bodies, which would have eluded any other mode of observation. For this purpose the crystal must be cemented over a small aperture in a thin sheet of brass, on which the focus of the lens must be exactly adjusted to fall.* i . If, instead of applymg the eye to receive the light so dis- persed, we place a screen at some distance in a darkened room, the apparatus is converted into a solar microscope, and the rings -will,be seen projected on the screen. The construction of the ‘apparatus | ono ed is as follows: A B isa brass tube, within which are fitted, first, a fixed diaphragm, aa 0b b, carrying the first plate of tourmaline in its centre; secondly, a diaphragm,. «cdd, moveable freely in its own plane by means of the pin passing through a slit in thes ide of the cylinder, A B, whic occupies an are of about 120° of its circumference. This is des- ined to receive the crystallized plate, d d, while a cylinder, Ah e ef f, made to-slide and turn smoothly within A B carries. Ahe second tourmaline, ff. It is essential that the tourmalines -employed for. this purpose, and especially the posterior one, should be perfectly free from all flaws and bleinisties but large _plates not being required, this condition is easily satisfied. The ‘plates so arranged, and brought as near together as possible; the extremity. A ofthe cylinder A B is fitted to slide somewhat stiffly on the brass tube P Q, furnished with a lens L, of about two inches focus, and a screw P P, by which it can be adapted to the apparatus usually employed for reflecting a sunbeam into -a darkened chamber. ‘The sliding motion’ of the cylinder A B allows the focus of the lens to be adjusted so as to fall exactly on. the first surface of the posterior tourmaline f, while its rota- _tion suffers the axis of the anterior one to be placed perpendi- cular to the plane of reflection. By this arrangement: two advantages are gained. The reflector employed (though metallic) always polarises a more or less considerable portion of the Teflected beam, which in any other position is partially or totally extinguished by the first. tourmaline, and a great loss of light -ensues, which itis of the utmost consequence to avoid : more- over, by this disposition, the action of the reflector is brought to. _conspire with that of the tourmaline, and the polarisation of the light. which: traverses it (which is never rigorously exact) is _ thereby rendered more complete. 7 Rr Gs de It is convenient to have sliding tubes containing lenses of dif- ‘ferent: focal lengths, according ‘to the erystal examined, ‘for the * I have now an apparatus preparing, in which the first plate of tourmaline itself is _ formed into a double convex lens, by which the loss of light at. two surfaces \will:- be sup- . pressed. It is easy to adapt such a lens to a double microscope, for the purpose of detect- _ Ing microscopic irrégularities; and I have reason to suppose a yariety.of curious results will be brought to light by these means, otlandent inaigine 1821.1] © Crystallized Bodies on Homogeneous Light. 181- intensity of illumination any point in the screen being, cateris’ paribus, as the square of the focal length; consequently, when: the rings lie within a very small angular compass, a greater illu-’ mination of every part of them may be obtained by using a lens’ of a longer focus. . | ' The dimensions of the figure, fig. 6, are nearly of the actual’ size. : ) | | ArTICLE II. Observations ona Memoir “ On the Theory of Franklin, accord-. _ ing to which Electrical Phenomena are explained by a single Fluid,” read at the Royal Institution of the Sciences at Amster-, _dam, by M. Martin Van Marum, Knight of the Order of the _ Belgic Lion, Secretary of the Dutch Scientific Society, Director. _ of the Teylertan Museum, &c. &c.* (With a Plate.) ay (To the Editor of the Annals of Philosophy.) SIR, Dec. 13, 1820, Ir has been repeated so often as almost to require an apology: for its introduction, that. the Baconian philosophy proceeds by» discovering and establishing facts, holding that upon such:a, foundation alone, can be raised any structure deserving the name, of. science. The philosophy which has happily been almost; exploded by Bacon and his successors, lays its foundation in: hypotheses ; and the labours of its adherents are spent in inge-; nious conjectures, or in efforts to bend the various facts disco-, vered, to give those conjectures an apparent truth. A Baconian, philosopher gathers his maxims and principles from the united : rays of numerous observations and experiments, and as they are, received in all the simplicity with which the facts themselves express them, they yield to the mind all that satisfaction and: confidence which spring from the clear perception of truth. On: the contrary, an hypothesis is incapable of teaching any truth at. all, and ought, under no circumstances, to be received as “ a, confirmed truth ;” the observation being certainly well-founded, » * that an hypothesis, however satisfactory as far as concerns the» explanation of all the phenomena for which it has been proposed, cannot nevertheless, for this reason, be considered as. incon-» testibly proved.” + : hs _ Unfortunately the worthlessness of. hypotheses is, not. their - : ecient evil; they invariably tend either to mislead the mind - rom those conclusions naturally deducible from experiments, or _* Ann. Phil. No..96, p. 440. : ‘t Ann Phil. No. 96, p. 441. I conceive this must be the meaning of the sentence which it is apprehended (though without an examina ion of the original paper), must be mistranslated, Pig eo) y 182 _ On Franklin’s Theory.of Electricity. [Mapnox,, to induce an: extravagant. regard to some circumstances to thei neglect. of others equally or moré important. Thus. Franklin,, whose experiments and observations. will ever rank him among: the first.philosophers, has impeded the progress.of science by, his: hypothesis respecting electricity, which now, im.spite of! thes axious exertions of his old and-most-respectable disciples, seems inevitably doomed to death. M. Van Marum however is ofvt® different opinion, and to arrest the progress of the dualists, by which he means those who think there are two electric fluids, by the assistance of the Royal Institution of the Sciences at Amsterdam, he has thrown down the gauntlet to all the world, in a paper read before that Institution im October, 1819, and in their name he hes called for an answer to an experiment which’ lie originally published in the year 1785, and considers still unan- swered and unanswerable. - "Phe experiment which has-been thus put forward ag am expe- _ rimentum crucis' of the Franklinian hypothesis, is given so little in detail, and’so many of the important circumstances are’ omit- ted, that it is difficult to deduce from it a perfect explanation of the phenomena. From the whole of the statement, however, the facts upon which M. Van Marum relies may perhaps’ be suf- ficiently collected. It seems: then, that in: the formation and collection of positive electricity, M. Van Marum employed two* conductors ; one in more immediate connexion with the machine, which he has called the first conductor, and a second intended to contain a larger quantity of electricity, which he calls the receiving conductor, and this’ latter was placed: at a little dist ance from the first conductor. It then appears, that. he was: able to ascertain by the form of the spark, that. theelectrie fluid’ which was generated by the machine, and communicated tothe’ first. conductor,. passed from that conduetor to the’ receiving conductor. Take . « Perhaps there’ cannot be shown in philosophical reasoning? a: miore flagrant instance of the evil of an hypothesis and its per nicious influence over the! mind, thanthat-M. Van Maruny and his friends should: esteem this’ “‘ a most evident proof in favour’ of the theory of Franklin.” That is, because one’ electric fluid’ can pass from one conductor to another, therefore’ there is no’ other electric fluid. _ . uA _ This experiment could satisfy only the most zealous adherents? of. the: Franklinian hypothesis; but: another, which is twice? detailed, is considered irresistible. It was so powerfully operas ee a-French philosopher as to have silenced hinr for ten * 7 The material circumstatices of this experiment-can hardly be gathered from either statement of it, but by comparing the two accounts together, the, more important fact® may probably be . * Ann. Phil. No. 96, p. 447. . 1820 On Franklin’ Theory of Electricity: ee distinetiished.* From the comparison’ of the two’ statements; if appears that if “a button of copper*” which either'was fixed in’ ad conductor charged by' the’ machine with positive electricity, or ‘commiunicating with theearth, acquired a charge ‘of an’oppo=' ‘sité kind to’ that of the electrified’ conductor “be brovght within’ six inches‘ of the large globe” * of the conductor negatively elec- trified, the ramified’ electtic fluid passes from the’ positive to the’ negative conductor: This'lastexperiment’in ‘M. Van’ Marum’s* hands has proved victorious over every person with whom it has come in contact’; and it is'not, therefore, surprising that it should’ lave’ convinced’ even’ the venerable, sober-minded, and’ intel= livent Franklin ofthe truth’ of his own hypothesis. ni | Happily, however, with whatever gemius’ an hypothesis may’ be first suggested, or however ably and’ inflexibly supported,’ truth will ultimately become rebellious. Just’ as in-this’ case, where the similarity of the effects of'positive and negative elec= tricity is so-obvious: In mmmumerable mstances* that it has’ been” inrpossible to repress the opinion’ that ifthe phenomena of posi- tive electricity arise froma peculiar fluid, so do those of negative- electricity. While’a philosopher whose mind’ is accustonred to” inductive’ reasoning will not*be able to avoid some surprise that® stich a than as Franklin, on seeing M. Van° Marum’s experiment; | should say, “this proves the theory-of a simple electric ‘fluid; | and it is now high time’ to reject’ the theory’ of two” sorts: of* fluids.” ‘To'such a philosopher, it must’ appear singular that-it should not have suggested itself to Franklin, that it might’ have” been, that’ the negative electricity had arisen’ from a peculiar’ fluid, which’ was heldin’its conductor by a stronger attraction” than that by which the positive’ electricity was held in’ its’ cons” ductor; or it might’ have been that the air (which probably’ occasions the zigzag ramified appearance of the positive spark), opposed less resistance’ to the’positive fluid than'to the: negative; or it might have been’ that the form ofthe button afforded greater facility to the transmission of an electric fluid’ than that’ of a> large globe; and either of these circumstances: would account’ forthe passage of the’electric fluid’from the positive'to'the nega-" tive conductor, consistently with the notion ofa negative electric’ fluid: But if every one ofthese circumstances’ were shown not” to’exist, theexperiment could not possibly prove that there was no ‘negative’ or resinous electtic fluid.’ Even'then the fact that’ the’ positive electric fluid had been’ attracted’to the negative” conductor, would no nore have’ proved the: non-existence ‘ofi a” negative or resinous electric fliid, than’ the ‘fact that concen trated sulphuric acid ‘attracting’ water to’ itself proves: the’ non= Ceetenee OF sips aera FP? 8 RA Ome Rais | “But M: Van Marum’s experiment’ will be better*explained) | atid’ his* observations answered, by ‘atiother experiment; w ich © Min SPE NG V6 PAG \ 184. On Franklin's Theory of Electricity, [Manrcu, was published in the Philosophical Transactions so long since as, the year 1789. - és | “‘ The escape,” says Mr. Nicholson, in.a paper detailing some experiments with a powerful machine, “ of negative electricity from a ball, is attended with the appearance of straight sharp sparks with a hoarse or chirping noise. When the ball was less. an two inches in diameter it was usually covered with short flames of this kind, which were very numerous, ! “When two equal balls were presented to each other, and: one of them was rendered strongly positive, while the other remained in connexion with the earth, the positive brush or ramified spark was seen to pass from the electrified ball: when: the other ball was electrified negatively, and the ball, which before had been positive, was connected with the ground, the- electricity exhibited the negative flame, or dense, straight, and more luminous spark, from the negative ball; and when the one ball was electrified plus and the other minus, the signs of both electricities appeared. If the interval was not too great, the: long zigzag spark of the plus ball struck to the straight flame of the minus ball, usually at the distance of about one-third of the length of the latter from its point, rendering the other two-thirds | very bright. Sometimes, however, the positive spark struck the ball at a distance from the negative flame. These effects are represented in Plate V. figs. 1, 2, and 3. te wo conductors of three-quarters of an inch diameter, with spherical ends of the same diameter, were laid parallel to each ather, at the distance of about two inches, in such a manner as that the ends pointed in opposite directions, and were six or eight inches asunder. These, which may be distinguished by . the letters P and M, were successively electrified as the balls were in the last paragraph. When one conductor P was posi- tive, fig. 5, it exhibited the spark of that electricity at its extre- mity, and struck the side of the other conductor M. When the last-mentioned conductor M was electrified negatively, fig. 4, the former being in its turn connected with the earth, the sparks ceased to strike as before, and the extremity of the electrified conductor M exhibited negative signs, and struck the side of the other conductor. _ And when one conductor was electrified, plus and the other minus, fig. 6, both signs appeared at the same time, and continual streams of electricity passed between the extremities of each conductor to the side of the other conductor posed to it.” ‘ The effect of a positive surface appears to extend further than that of a negative.” This experiment will reed few comments, for it is sufficiently . evident that if the form of a spark or its direction, is to deter- mine ‘the existence of an electric fluid, this experiment proves that there are two. Nor is it easy for an unprejudiced observer. * Phil. Trans, vol. Ixxix. pp, 27£—280. ue Angresed tor the Arnals of Philosophy... Published by Baldwin, Gadock & JoyMarch 11827. wag ae he ale j el dg bch 3 ae or eee Salat We ah porting one: hypothesis’ by another, nor do [ perceive that t own hypothesis is more contrary to his own propositions than the Franklinian hypothesis isto the’ analogies of nature.’ Franktin supposes that there is’im all bodies a natural quantity of electric’ fluid, which’ cannot be perceived, and produces no effects ; and’ Which consequently is from its very nature incapable of ai proof; that it so perfectly combines with bodies as entirely to ose all its properties, yet is held by so slight a force as to be removed by the least possible attraction; as in the communica- tion of negative electricity. Such a fluid is perfectly anomalous,, leaving, therefore, the hypothesis not only unsupported by fact, but even by analogy. : But it may be said, if there be two electric fluids which on combination neutralise each other, what becomes’ of that com- pound?’ It'certainly would not follow that if no answer could be given to the question, therefore the Franklinian hypothesis must be correct. That’ would still be entirély an hypothesis, and,, therefore, ought at once to be rejected, as offermg the wrong, path to truth; nor ought, on the other hand, any hypothesis to’ be received in réply to such a question. In order, however, that. we may not be’ misled from the proper answer, it may be well to’ observe that it ought not to be expected that the compound’ fluid should possess the same properties as its’ component parts’ any more than’ water does, or nittic acid. Another question may perhaps lead us to the proper answer. Is there any thing always’ produced’ by the combination of two electricities ? If there be, we are bound to'assume thatthe produce is the compound of tlie two fluids. Oxygen and hydrogen combine, and the caloric. being diséngaged, water is produced; and we assume that water is a conipound of oxygen and hydrogen. The two electric fluids combine, and’ caloric is produced, and that not from any” concussion of the air, for it isproduced in vacuo. Why then is. not the same inductive reasoning to be admitted in ethereal as in gaseous fluids ? Why should we not admit the suggestion which has been offered,* that calorie’ is a compound of the two elec- tricities? ‘Tremain, Sir, yours, &c. wile, * Eosny!on' Heat; Light, arid Electticity, by C.'C. Bonipass: 182s} The. Edinbureh Pharmacopeia. 18% Awricee TED. Remarks on Mr. Phillips's Analysis of the Pharmacopaia Collegit - Regit Medicorum Edinburgensis;* containedina Letter addressed . to R. Phillips, Esq... By Dr. Hope, Professor of Chemistry in the University of Edinburgh. ce SER, ; , Edinburgh, Feb. 12, 1821. Tue Royal. College of Physicians of Edinburgh in preparing: new editions of their Pharmacopeia gladly avail themselves of every suggestion that may enable them 'torender that work wor- thy of the public confidence ; and I entertainno doubt that here» after they will continue to be thankful for services of the like description under whatever form they may present themselves. Well acquainted with your knowledge: of chemistry in general, and your attention to the chemical department of Pharmaco-' peias in particular, I confidently expected that the criticism which you have thought it worth while to give of the last edition, even after a lapse of nearly four years smce its publication, would have afforded much useful information to guide us in pres ore a future one. I cannot, however, conceal how greatly I’ ve been disappointed in this respect. As your remarks are far from being in a strain of approbation, and as: the chemical department had in a great measure been entrusted: to me, I feel. that: 1 owe it to the College, over whom I had the honour of- residing, when that edition came forth, to maintain their credit: in regard to this work, which, from a certain degree of national authority in the preparation of drugs attached to it in this: part of the empire, ought to be as free from blemish, and stand as high’ inthe public estimation, as possible: Tundertake the task without reluctance, both because I consi- der it a duty incumbent upon, me, and because, if I do not deceive myself, I can easily make it appear that the strictures: which yow have published upon its formulas are by no.means well founded.. | Had you been aware that the late edition was several years: under revisal; and that many trials were made of the’ different’ , ae directed in the most esteemed Pharmacopceias in ope with the view of ascertaining their comparative merits, and' that those adopted by us have in general been: many times repeated, I am persuaded that the tone at least of the criticism would: have been considerably different. : Permit me to observe that most of your objections to’ thie? formulas apply to the relative quantities of the materialsemployed,. and: rest-upom these quantities deviating from the proportions-of* ss © Alona of Phitonopliy, Nov ke (Now Setieny : 188- Dr. Hope’s Remarks.on:Mr.:Phillips’s Analysis [MaAxrcu, combination stated in Dr. Wollaston’s table of chemical equiva- lents. I apprehend, however, that you have made an application of this beautiful and valuable contrivance which its very inge- nious author never contemplated, and could not now sanction ; for though that table displays the proportions in. which different. substances combine, it by no means displays the relative quan- tities of the substances to be eteiiloahad, when. decompositions are to be effected, particularly by single affinity. It has been long known to chemists that to achieve the complete decompo- sition of any quantity of a compound, an excess of the decom- posing material is either absolutely necessary, or very useful, by accelerating the operation. | Were I not addressing myself to a person thoroughly versed) in the science of chemistry, it would be easy to explain in detail’ the reason. of the circumstance ; but it will be sufficient to: remark that this excess is in some cases indispensable from the? disposition of the decomposing agent to form a super or bicom- pound with the ingredient to which it is to attach itself, as im: the decomposition of nitrates and muriates of alkalies by sulphu-' ric acid to be immediately brought into view; and also when the substances are in the state of dry powder, in order that’ each particle of the compound may fully and freely encounter those’ which are to act upon it. . The reader who may think it worth his while to peruse these’ observations is particularly requested to direct his attention to: your critique commencing in p. 58 of the first number of the Annals of Philosophy, and to read in succession the different articles to which a reply is now to be given. | | ~ Acidum Aceticum Forte is the first substance of which you’ take notice, and your objection to the formula for its preparation: is, that the quantities of the salts employed are not such as are’ required for mutual decomposition. It is unquestionably true: that the sulphate of iron contains more sulphuric acid than is required to saturate the oxide of lead in the acetate, but it is of) advantage to employ this excess. » It facilitates greatly the dis- engagement of the acetic acid, and renders it unnecessary to. raise the temperature to so high a pitch as would otherwise be: required, by which means the empyreuma, unavoidable in an elevated temperature, is in a great measure prevented ; hence at the trifling expence of an additional quantity of the sulphate of iron, and of an increased size of utensil, there is a saving of time and of fuel, and a vast gain in the quality of the product. The: object of this process is to obtain a very strong acid capable of. dissolving camphor at a cheaper rate than from acetate of: coppers. , cidum Muriaticum.—Upon the preparation of this substance: you remark, that ‘ Equal quantities of sulphuric acid and com-) mon salt are directed to be employed in the preparation of this acid. It will be seen.by Dr. Wollaston’s: séalexthat the requisite geod) ué of the Edinburgh Pharmacopeia. 189 ‘proportions are 8-4 parts of acid to 100 of salt.” Notwithstand- * mg your remark, you surely cannot suppose that in directing _ these relative quantities, the College could be ignorant of the ‘proportion of the ingredients of muriate of scda. Permit me then to:remind you, that the numbers in'the scale indicate the quan- tity of sulphuric acid necessary to saturate a given quantity of ‘soda, but by:no means: the quantity of this acid necessary to -effect the decomposition‘of the muriate with the greatest suc- cess and-convevience. It must, I presume, for the moment have ‘escaped your recollection that sulphuric acid is much disposed -to-form a supersulphate of soda, and consequently that if no ‘more acid be employed than is barely sufficient to saturate the ‘quantity of soda contained in the muriate, a considerable portion -of the muriate will remain undecomposed. | After many repetitions of the process, I may confidently assert - that. the proportions assigned m the Pharmacopoeia afford a larger product of muriatic: acid in a shorter period at a smaller ‘expense of fuel than those which you recommend as the requi- ‘site. : Acidum Nitrosum.—I suspect that we can turn to little ac- ‘count the remarks which you have made on the process for ‘preparing this substance, as ! am persuaded from ample expe- rience that they are not correct either in regard to the quantity ‘of the product, or the condition of the acid which is obtained. ‘Youhave thought fit to condemn the proportions directed in the -Pharmacopeeia as unproductive and injudicious on the result of ‘a solitary trial, which you state in the following words: * I put -into a retort 24 parts of nitre and 16 of sulphuric acid, and car- ‘ried on the distillation as long as nitric acid was produced.” The ‘product was of a straw colour, evidently containing but ver ‘little nitrous acid, and its specific gravity was 1513 instead of 51520, as stated in the Pharmacopeia. It weighed 11°5 parts, whereas 24 parts of nitre are capable of yielding 17 parts of acid, ‘provided. sufficient sulphuric acid is employed ‘to afford water | ‘enough to condense the nitric acid.” The results which I have -had uniformly for many years are extremely different.. ~ The . quantity. of acid amounts to 15 parts ; it possesses a full orange- red colour; and its specific gravity, never less than 1520, occa- ‘sionally (when the nitre’ has been previously well dried, and the ‘sulphuric acid boiled) has been'so high as 1540. ”' , I cannot refrain from expressing my surprise’ at the followin ‘paragraph: “ | have already observed that the ‘acid which / obtained has only a!straw colour instéad of a redone, as the College seemed to expect, and I believe that ‘whenever this acid vhas.this red colour, it is owing to the presence of common salt ‘in the nitre, the chlorme:of which ‘partially decomposes the tnitere ection ainiiiglo al guise esi tsipal Y Bend ESS SOT >» ‘Every chemist knows that nitric‘acid acquirés'a red colour by _ as bright as when it was several minutes distant from the moon’s | limb. Rain, between noon the Ist of January and noon the Ist of February, 2°115 inches. Evaporation, during the same period, 0-680 inch. Mean heat of January,37°. Thermometer, lowest, Jan. 4th, = 21°. Highest, Jan. 18th, = 491°. Articie VII. On the Going Of a Clock with a Wooden Pendulum. y Col. Beaufoy, FRS. (To the Editor of the Annals of Philosophy.) DEAR SIR, Bushey Heath, Stanmore, Feb. 7, 1821, In the Annals of Philosophy for February, 1820, was pub- lished the going of a clock with a wooden pendulum, and also a description of its construction; but as it may be more satisfac- tory to have the account of the rate for a longer period than 12 months, I have the pleasure to send a table of the clock’s oing, during a second year, and the result corroborates the avourable impression I then entertained of its accuracy. I remain, dear Sir, your obliged servant, Marx BEAvroy. [Marcu, Col. 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A a TTA 2DLy re 206 Mr. Deuchar’s Remarks [Maren, ARTICLE IX. Remarks regarding the paperanents upon Flame, performed with the Apparatus for discharging Ordnance without the Use of a ‘Light or Match-Lock, By Mr. John Deuchar, Leeturer on Chemistry in Edinburgh. (To the Editor ofthe Annals of Philosophy.) SIR, 21, Lothian-strect, Edinburgh, Feb. 10, 1821. Ar a meeting of the Wernerian Natural History Society, which was held to day, Fread the continuation of my account of the experiments performed with the apparatus for discharging ordnance, a description of which was given in the last number of the Annals. In this paper I have entered upon the cause of the results which present themselves. . 1 have endeavoured to show by experiments that it is not in the slightest degree electrical, but that it-may, with more propriety, be ascribed to free caloric in a so far insulated or condensed state. I have not yet tried the whole of the experiments [ had chalked out to myself; for. the proof of this, so far, however, as I have gone, they verify the eonclusion. I have also noticed more fully the nature of the flame while in rapid motion, and the alterations of its effect upon. substances by retarding that movement ; when its force is not retarded, it passes through many inflammables without affecting them in the least ; but when its velocity is so far stop- ped as to bring it for a longer time in contact with the substance to be acted upon, then it begins to display, in a greater or less degree, the usual effects of caloric. _ As you will find the minute details of these experiments in the third volume of the Transactions of the Wernerian Natural His- tory Society, to be published in a few days, I should not have troubled you with any observations at present, had it not been that from what was mentioned at p. 93 of the present volume of the Annals, regarding the experiments-with wire gauze, it might appear that the gunpowder could not be fired through the wire uze used in Sir H. Davy’s safety lamp, without the wire being injured. Ihave since found that the wire gauze I bought of the manufacturer, and which he assured me was the same as that used in the safety lamp, was by far too fine, and that it was on this account the flame sometimes forced away a part of it. The following experiments, which I extract from the paper above alluded to, will remove any misconception that may have arisen on this part of the investigation. ‘The wire gauze I used was made of brass ; an inch of the finest kind-econtained 70° meshes in the length, being 4,900 in the square; and the coarsest kind contained 56 in the length, being 1,296 meshes in the square * 1821.) regarding the. Experiments upon Flame. vt «207 sinch. Now upon examining two of the lamps recommended, by Sir H. Davy, the one with copper gauze, and the other withiron . .gauze, | found the former had only 676 meshes.in the square inch, and the latter 784. meshes. in the same space. Lixperiment 13.—A tube which could be separated into six pieces of nearly the same length, was screwed to the apparatus (Plate LI, p. 89), making the distance from the top, A, to the »bottom fully 23 inches. A’ piece of the coarser wire .gauze, valready described, was put upon the hole at the joining, a, when the fulminating. powder was exploded at A, the flame. passed othrough the gauze, and appeared at the bottom of the tube. The same kind of wire gauze was next placed at a and 6 at the same time, and then at a,.6, and c, and the flame passed through all the pieces. This effect was also obtained when similar pieces of wire gauze were put at all the five joinings of the tube at once. In this last result, the first piece of wire gauze was 41 inches from the top, A; the second, 81; the third, 12; the fourth, 16; and the fifth, 20; and the flame appeared at the bottom, after a passage of nearly 234 inches, through five pieces of the wire auze. Experiment 14.—As I could. not get the flame to pass through the whole of the tube, when I increased the joinings beyond 231 inches, it was impossible to try an additional number of pieces of wire gauze, by adding them inthe same way. I, therefore, increased the number by putting more than one at the same joining. I found, upon repeated trials in this way, using the tube 15 inches long (as represented on the plate, p. 89, fig. 1), that the flame could pass through three, six, nine, and-twelve pieces, at once: there being placed one, two, three, and four pieces at each of the jomings, a, 6, andc. ! Laperiment 15.—Although, by the two last experiments, it was proved that the-fiame could pass through the coarser wire gauze ' owhen increased even to 12 pieces at once, yet it did not follow that it was not thereby altered somewhat in its nature A pro- sbable change was, that it might. become inert. with regard to inflammables, as takes place in the different safety lamps, and »particularly that of Sir H. Davy. Several experiments were tried to ascertain if this suggestion were correct ; first, the wire ‘gauze was put at a; then ata and 0; and lastly, at a, 6, andc; placmg at the same time, during each trial, a quantity of gun- powder ina pieceof flannel.at the bottom of the tube ; and in all oof these I found the gunpowder to be inflamed, and the wire »gauze not:to be in the least injured. Experiment 16,—I1 next tried the result of firing the fulminat- -ing powder, with the finest wire gauze placed first at a, then at @and 6, and then at. a, 6, and c, and found that:the flame still vappeared at the bottom, B; showing that the gauze, although -much finer than that used in Sir H, Davy’s safety lamp, was not impervious to this flame. In some of the experiments I found a 208 Machine to measure a Ship’s Way by the Log Line. [Marca, hole to have been made in the centre of the wire gauze, and sometimes the parallel wires were forced wider. This was ve often the case when a piece of wire gauze was put at all the join- ings, a, b, and c, and then it was the gauze at a which was torn or otherwise injured. Experiment 17.—In order to ascertain iftheflame still remained unaltered, notwithstanding its having passed through the finest wire gauze, a quantity of gunpowder in flannel was affixed to the bottom of the apparatus ; and it was inflamed through one, two, and even three pieces of the gauze. ' Here the same occasional appearance, noticed in the last experiment, occurred with regard to the upper piece of wire gauze. lam, yours respectfully, JoHN DEvucHaR. ARTICLE X. On a Machine to measure a Ship’s Way by the Log Line. By Mr. J. Newman | (To the Editor of the Annals of Philosophy.) : DEAR SIR, I ogsEerRve in the last number of the Annals of Philosophy a paper referring to the account I have given of a machine to — measure a ship’s way by the log line, in which a prior claim to mine is set up for the invention. This I conclude to arise from the circumstance of my not having mentioned the date of the instruments I made; and from it your correspondent supposes that the date of the publication of the paper is that of the invention. - Itis now at least 40 years ago since I invented and made the first instrument in question. Capt. Hubbard, then of the East — India service, had the first of them, and between the years 1785 and 1798 they were publicly sold by Messrs. P. and J. Dollond, and Mr. George Adams, with their names on them; but my account book of that time is destroyed. My present account book begins in 1794, and | find that Messrs. Dollonds had one of the instruments on Sept. 4, 1797 ; and another on the 27th of the same month. These dates can no doubt be easily verified by reference to their books. I made several, perhaps 16 or 18, between the dates I have mentioned, but my attention being’ called to other things, I did not pursue the subject with any degree of earnestness. I remember that Capt. Clayton had one of the first that I made in the year 1785, and he recommended me to take it to Sir Charles Middleton, at the Navy Office, 1821.] On the Comparative Advantages of Oil and Coal-Gas. 209 Somerset House, who spoke well of it, and advised me to take it to the Admiralty ;~but I did not pursue the matter further. > As the only question is merely as to the date of the invention, and not to any imaginary superiority in principle, I need not direct attention to the supposed advantage of either one or the other instruments. I am, dear Sir, : Very respectfully yours, &c. J. NEWMAN. ° ARTICLE XI. On the comparative Advantages of illuminating by Gas produced from Oil and from Coal. By M. Ricardo, Esq. (To the Editor of the Annals of Philosophy.) DEAR SIR, | Tue utility of employing gas for the purpose of illumination is no longer a subject of doubt, but from what substance it is most advantageously obtained, whether by decomposing oil or coal, is not yet decided by men of sciertce. I have, therefore, been induced to enter into an,examination of the comparative advantages of the two in order to draw the attention of those who are engaged in the formation of gas light establishments to the subject, and to enable them to arrive at a tolerably correct opinion, which it would be most advisable to adopt. It is my intention to consider 1. The qualities of the two gases for producing light. 2. The comparative facilities with which an establishment for the production of either may be carried on. 3. The capital required for such establishments. 4. The comparative cost of the two gases. 5. Which is most desirable in a national point of view. | _ The gas produced from oil is much purer, and contains a much greater illuminating power than that from coal. The quantity of light produced from a given portion of oil gas is stated by an eminent chemist to be equal to three times the quantity pro- duced from coal gas: from the result of my own experiments, it is equal to four times ; for I have found that an Argand burner giving a light equal to six candles, six to the pound,- consumed one cubical foot in the hour. Mr. Accum, in. his work on Ga Lights, p. 276, states that an Argand burner of coal gas giving a light equal to three candles, eight to the pound, consumes two cubical feet per hour, Then as one foot of oil gas is equal to six-eandles, and two feet of coal gas are required to equal three candles, it follows, ifthe candles were even of the same size, that one volume of oil gas is equal toe four of coal in illuminating New Series, vou. 1. Oo 210. Mr. Ricardo on the Comparative Advantages .[Mancu, power. . If we take the mean of these statements, it will be as one to three anda half; that is, 20 cube feet. of oil gas will give as much light.as.70 of coal gas. | »» Oik gas requires. no purification; it contains no sulphuretted eo which is one of the admixtures of coal gas, and of this all the purification to which it, is submitted cannot wholly deprive it; the coal gas, therefore, acts upon all metallic sub- stances, and in the course of time must seriously injure the pipes through which it passes, and its accidental escape in shops and houses must prove’ highly detrimental ‘to all ornamental ildings, paintings, or any thing of which metals form a part. his cannot happen where oil, gas, is used ; for it contains no sulphuretted wag, and it is well known to have no action on metals. whatever.. It. may be said, that. the mode adopted for purifying coal gas effectually deprives it. of this noxious gas ; but experience has proved that this is not the fact, as in many places the smaller copper pipes show evident marks of being strongly acted upon, the bore being gradually filled up with sulphuret of copper. As this process takes place slowly, the diminution of light is not immediately perceptible, but it will become very evident after a time; and it may be expected that afier the lapse of a still longer period, the same evil may arise in the larger ipes, as iron is also liable to the same corrosive influence from its contact with this gas. The admixture of sulphuretted hydro- gen with coal gas must prevent its general introduction into ouses, as the sulphurous acid gas, which is given out during its combustion, would prove very annoying in a confined rogm, besides which, from the consumption of so much larger a portion of coal than oil gas to produce the same light, a greater quantity of moisture is generated, and much more heat is given out. From the above statement, it is very evident that the smaller bulk and greater purity of oil gas will allow ofits employment m dwelling houses without its producing the least inconvenience. If the pipes are well fitted together and properly proved before the gas is admitted mto them, no annoyance whatsoever need be apprehended ; and if a cock should be accidentally left open, and the gas allowed to escape, it may be immediately remedied without leaving so unpleasant a smell as that arising from the similar escape of coal gas. When any new improvement is introduced, we are too apt to place any possible inconvenience that may result from it man exaggerated point of view, and wholly te overlook those we are labouring under, and which it is intended to supersede. Thus the only possible inconvenience that can result from the use of oil gas is that which I have before mentioned, an accidental smell from carelessness, instantly detected, and as instantly remedied—an inconvenience to which we are equally liable in our present mode of lighting, in addition to which there is the trouble of trimming the lamps, the ehance of spilling the oil, not a very unfrequent 1821.) of illuminating by: Gas from Oil and from:Coal. 21% occurrence, and‘ many other disasters both in the use of oil and candles,. from all of which gas is: exempted; and: when the prejudice arising from the use of coal gas is once removed, and the greater advantages of oil. gas generally. known, there is no doubt ‘its great convenience, ‘superior. briliancy, and cheapness, will cause it to'supersede all other modes :of lighting, and before long, its universal introduction into dwelling houses may be con. fidently relied upon. : The second point for consideration is the comparative facility with which a coal or oil gas establishment may be carried on. The process for producing gas from oil is.very simple. The appa- ratus is easily managed, and consists of an iron retort heated over a fire: a very few days’ experience will teach a common working man how to regulate the heat. This retort-is connected by'a tube with the oil cistern, from which a small drop of oil passes into it. The quantityis regulated by a graduated cocks; there it is decomposed and converted into gas. This. passes through another tube at the other extremity of the retort intova condensing vessel, where, by a simple contrivance, the oil that is only volatilized returns back into the.oil cistern; the gas.is: then conveyed into a wash: vessel; where it passes through water to deposit any oil, or other condensible vapour, that may have come over with it, and from thence it 1s conducted into the gasometer for. use. , Coal gas:is produced by putting a certain quantity of coal in an iron retort placed over a fire, The coalis decomposed; the gas passes over into a large vessel, where it deposits its tar and ammoniacal liquor; it is then conveyed through a. mixture of lime and ‘water to deprive it of the sulphuretted hydrozen which is‘ mixed’ with it, a mest! troublesome and offensive: operation: after this, it is passed through water, where it is more effectually washed, and from thence it is transmitted into the gasometer. These are the processes required for producing the oil and coal gas:; but we-shall bétter understand the trouble attendant on the latter bya comparative view of two establishments fora thousand lights each, one for‘oil, and the other for coal gas, each light consuming annually, upon an average, 2000 cube feet of oil gas, ‘and 7000 cube feet of coal gas. The whole annual consumption of'the one would be 2,000;000, of the other 7,000,000 cube feet. The quantity of light required in winter is of course much greater ‘than in‘summer, and either establishment must be made upona ‘seale to meet the demand that may be necessary on the shortest ‘days. The fortnight before and after Christmas, or about that ‘time, may be taken as the month of the greatest consumptiom; “and we may assume that during this month, nearly one-fourth of the: whole quantity: would be required. | 1 may mistake in this ‘estimate, but it can be of no consequence, as it will equally apply to both establishments. The average quantity of oil gas required would be, during that.time; somewhat above 16,000 cube feet. 02 “ 212 Mr. Ricardo on the Comparative Advantages. [Marcu, per night, and 56,000 of coal gas. To produce that quantity of the former, eight or 10 retorts would be sufficient, each retort ‘ix feet long, and six inches diameter. One of this dimension would, if necessary, produce 3000 feet per day, but it is found more advisable not to work them to their full extent, and always to have some in reserve. One gasometer containing 12,000 cube feet, or two of 6000 each, would be required. The oil cistern, the condenser, and wash vessel, are so constructed as to occupy. but very little space, the condenser being over the cistern, and the wash vessel under it, the gasometer occupying by tar the largest portion of room. From the repeated trials in various oil gas establishments, it has been ‘ascertained that 10 gallons of oil snen 1000 cube feet of gas, and require one bushel of coals or decomposition: 2,000,000 feet of oil gas, therefore, would require 20,000 gallons of oil, weighing between 78 and 7% tons, and 74 tons of coal; so that about 153 tons of materials would be annually wanted in this establishment, all of which would be consumed, or converted into gas. In the coal gas works, 40 retorts at least would be required.* ach retort is six feet long, and one foot in diameter, and would be charged with two bushels of coals, which quantity would require eight hours for decomposition. At the end of this time, the coke would be removed, and fresh coals putin. The above- mentioned quantity of coals would give out 560 cube feet of gas, estimating 10,000 cube feet for every chaldron. The utmost quantity of gas which one retort could produce would be 1680 «ube feet, working night and day without intermission : 34 is the number actually necessary; but in an establishment like this, the wear and tear would always be requiring some to be replaced, I have, therefore, taken the number at 40. The vessel to receive the condensed tar, oil, and ammoniacal liquor, must be of considerable size, as also those for burning the gas, and for washing it. One gasometer of 40,000 cubic feet, or two of 20,000 each, would be scarcely sufficient. To produce 7,000,000 cube feet of coal gas would require 700 chaldron of coals, and 175 for carbonisation, weighing altogether 1,181 tons, besides 50 tons of lime for purifying. , In a coal gas establishment there will be a. conveyance required for 1230 tons of materials, the greater part of which are returnable in bulky articles, such as coke, tar, ammoniacal liquor, for each of which a market must be found, as the greater part of our estimated profit is derivable from them ; and of the two latter articles, the product is already so great as very far to exceed any possible demand for them: so that a further convey- ance is required for more than three-fourths of the above esti- mated materials, and large premises and reservoirs to contain them till disposed of. Added to these, there is produced a very: * See Peckston on Gas Lights. ~ 1821.] of illuminating by Gas from Oiland from Coal. 218 large quantity of hydrosulphuret of lime, which is extremely offensive and quite useless. In the oil gas establishment, the conveyance of 153 tons of materials is all that is required, the whole of which is consumed, and the entire profit derived from one product only, and that the sole object of manufacture. From the above investigation, it is clear that on this point also the oil gas must be infinitely preferable as deriving its profit from the consumption of materials of small bulk, and the product. being only one article readily disposed of. It is, therefore, I think, evident, that such an establishment must be carried on with much less trouble than where the materials are extremely bulky, and the profits derivable from various articles, some of which are disposed of with difficulty, and are together almost as bulky as those from which they were originally produced. From the foregoing statements, it must clearly appear that the capital required for the establishment of an oil gas work must be considerably less than would be necessary for one of coal gas,. The fewer retorts, the smaller size of the gasometers and convey- ance pipes, the much greater simplicity, and consequently cheap- ness of the apparatus, together with the very little labour and superintendence required in works even upon a very large scale, prove clearly, and without any further comment, that the capital requisite in the one will, as already mentioned, bear no proportion to that necessary in the other. This is an object of some consequence to those embarking in such an undertaking, as the risk of loss in case of failure is comparatively small, and consequently less difficulty will be found in forming an oil than a coal gas establishment. ~ The next subject for consideration is which is the more eco- nomical method? and it may appear surprising to many that light from oil gas can be afforded to the consumer as cheap as that from coal, and at the same time yield as great or greater profit to the Company supplying it. This is, however, the case, though we have not such satisfactory data to go upon as to make it clearly demonstrable, from being unable to ascertain what the protts of the Coal Gas Companies really are, and which can only be assumed from the known dividends which are made upon their shares. The difficulty of calculating profits must always be increased when they are derivable from an average of various articles, for some of which there is a fluctuating demand, and _ which, from their increased production, are likely to diminish in “yalue. From some known data, it is supposed that the cost of coal gas to the Companies, reckoning the sale of coke, tar, &c. would be about 10s. per 1000 cube feet; the selling price is esti- mated at the rate of 15s.*: it may be more, but is Certainly not 2 Since writing the above, I have been informed, on good authority, that in some of the provincial cities and towns, the selling price of coal gas is estimated much higher n 15s. per 1000 cube feet. This is what may be expected, for should the supply of oal gas become much greater, in consequence of an increased demand for it, without 214 = Mr. Ricardo onthe Comparative Advantages [Mancn, less than that, This would give them a profit, of 50 “per cent, on their capital, The highMitiretigsn quoted, which 1s. of the Bristol Gas Works, is but 10 per cent.; and the chartered Com, pany in London, which possesses advantages superior to jany, only divides eight per cent. At is difficult to account, for thisg but on the supposition, that the making of the gas must cost them much more, or that there must be some mismanagement, er considerable waste. We will, however, assume that it only costs 10s, per 1000 cube feet. _ The profit and loss account ofan oil gas establishment,may be calculated very.easily, Ten gallons of oil will,produce 1000 ‘enbic feet: this may be considered the average, quantity, and taken from the result, of various trials where oil gas is used. Oil suitable for the purpose may be aow procured for 20/..per ton, but as the price of oil,at present\is very low, and may not he con- sidered a fi average, we will take it at.25/. per ton. or about 2s, per gallon. The cost then for, producing 1000 cube feet of ‘oil gas will be as follows ; ME x8. ed. 10 gallons.of oil at 2s. per gallon .......... 1 0-0 Uvbashelaficogle. i000 flees elon 0 1:6 ‘Labour, wearvand tear, and contingencies. .. 0 5 '6 | 1 2-0 _ At the present price of oil, the cost would be much less, Should oil advance beyond the sum at which.I have averaged it, it will be ofcourse greater; it may also be thought that goed underrated the expenses of wear and tear, labour, and contin- . gencies ; but the estimate is founded upon the data afforded by works. upon a small scale, and their expences generally exceed those of alarger description. Further, to meet those objections, I will take the cost of 1000 cube feet at 30s.: this is equivalent to 3,500 cube feet of coal gas, which at 10s, per 1000 will cost 34s. giving a balance in favour of oil gas of 5s. upon those pro- portionate quantities. In enumerating the advantages of oil gas over coal, it may not be irrelevant to consider it in a national point of view, as a nur- Sery for our seamen: supposing in every other respect the balance of advantages to be equal, this would give the oil gas a decided preference. liam aware that this advantage may be purchased too dearly, and that when coal gas was first Satrcdueadt, its great superiority over other modes of lighting made.it desirable that the benefit resulting from ‘the fisheries should in a degree be rélinguished, but now that other circumstances concur in. make 1821.] of tlluminating by Gas from Oil and from Coal. 215 ing the use of oil preferable, there can be no doubt of the propriety of considering this as an additional motive for prefer- ning oil gas. aM | : It has beensuggested by some intelligent gentlemen, whether, if the use of oil gas should become very general, the supply of oil would be adequate to the demand; and whether, from the increased demand, the price would not be considerably enhanced. When coal:gas was introduced, the demand for oil was dimi+ nished ; and the capital employed in that trade was diverted into other channels for the supply of the coal gas. Itis very clear that should oil gas become generally adopted, part of this capital willagain revert to its former employment as far as it supersedes coal gas; but where it only displaces lamps, no change will ensue; and where it)is substituted for candles, the use of tallow will be exchanged for that of oil. | After perusing the foregoing observations upon the compara tive advantages of oil and cual gas, and which J have endea- voured fairly to.state, 1 think it will be generally inferred that the former is greatly preferable to the latter; that on every point in which I have-examined them, it has the advantage ; that itas much purer and better adapted for every purpose of lighting; that it is prepared with much greater facility; ‘that it requires much less capital to establish works; ‘that it may be produced more economically; and that itis also more advantageous: ima national point of view. I feel some reluctance in offering this paper to you for inser- tion in the Annals of Philosophy, as the subject of it cannot ‘be considered as purely scientific ; but as the object of science ls to add to and improve our comforts and enjoyments, it may not be wholly foreign to your object to point out what scientific improvements are most likely toetiect this. From thesame motive I might also be deterred from‘subscribing my name, but the bare supposition that you, or your readers, should, for a moment, con» ceive that the writer of this was influenced by interested motives in seeking publicity to 11, would induce me to overcome every feeling of reluctance on that head. I trust my name will beva sufficient guarantee that 1 have no other motive for publishing this than that which every one interested in ‘scientific mprove+ ments, and their adaptation to the uses and comforts of society, must feel. | M. Ricarpvo. 216 «©. M.Julin on a peculiar Substance obtained [Marcn, ArTICLE XII. Ona peculiar Substance obtained during the Distillation of Nitric Acid. By M. Julin, of Abo. I Ave observed during the distillation of nitricacid froma mix- ture of crude nitre with calcined sulphate of iron, that when a peculiar kind of the calcined vitriol (known in Sweden under the name of calcined aquafortis vitriol, No. 3*):» was used, the first conducting tube + was lined with a yellow substance, which proved to be sulphur; the second tube became internally covered with fine white feathery crystals, nearly resembling the icy film formed upon windows on a cold winter morning.» | col- lected this substance by washing the tube with water; the ayuantity obtained by each distillation was exceedingly small, amounting to only a few grains. This substance is white, consists ‘of small fibres, which adhere to each other, and it feels soft to the touch; it sinks slowly in water, and is insoluble in it, whether cold or boiling, but the vapour of boiling water carries up a small rtion of it. ect is tasteless, but has a very peculiar smell, which [ have some difficulty in comparing with any other substance, but it somewhat resembles that of spermaceti. Muriatic acid does not act upon it; nor does nitric acid of specific gravity 145, but the acid, after having boiled with it, showed some slight traces of sulphuric acid on the addition of nitrate of barytes. When boiled in concentrated sulphuric. acid, it sublimed through it unchanged. A strong solution of caustic potash dissolved a very inconsi- derable portion of it, and gave with acetic acid a trifling precipi- tate, which was too small to be examined, excepting as to colour, and from this and a slight smell of sulphuretted hydrogen gas, | judged it to be sulphur. Oil of turpentine dissolves it easily, when heated. On cool- ing, a great part crystallizes in small needles ; it also dissolves easily in boiling alcohol of 0-816. On cooling, the greater part is deposited in crystalline fibres, but a small portion re- mains dissolved ; for the solution, on being poured into water, - renders it turbid. The alcoholic solution, when distilled with a rang anager left the greatest part of this substance in the retort, ut the distilled alcohol still retained enough to render water turbid by precipitation. '* This vitriol crystallizes in the water of the mine of Fahlun, and collected from the roek after the water has been pumped out, it is impure, and contains generally a small ion of pyrites. + The Mietillation is carried on in an iron retort, with a receiver connected by glass. 4ubes in the manner of a Woulfe’s apparatus, 41821.) - during the Distillation of Nitric Acid. 217 Held in the flame of a lamp, it burned with a greenish-blue flame, giving a slight smell of oxymuriatic gas; and when heated in a glass tube, it melted, boiled, and sublimed in needles, at a heat between 350° or 400°, and it sublimed slowly in long needles without melting at a heat of about 250°. Potassium burned with a vivid flame in its vapour in an open tube ; a great quantity of carbon was deposited, and water poured upon it gave, after saturation with nitric acid, a copious precipitate with’ nitrate of silver. The small quantity which I have as yet obtained of this sub- stance, and want of leisure, have prevented me from making more experiments upon it; but | purpose doing it as soon as the one and the other are more at my disposal: till then, I suspend forming any opinion of its composition. In some respects, it seems to resemble the perchloride of carbon which Mr. Faraday has lately succeeded in producing, and has so ingeniously examined. ) . : It is rather strange that sulphur should sublime unaltered in the vapour of nitric acid, as | have mentioned to occur in the case of this distillation of nitric acid, but it is really the fact, and may be accounted for by want of water for the sulphuric acid to combine with.* : agp Experiments on the above described Substanve: Ry R. Phillips, FRSE. &c. and M. Faraday, Chemical Assistant at the Royal _ Institution. In order to purify this substance, a small quantity of it was omg in a state of vapour over hot lime. By this operation, @ ittle sulphur, muriatic acid, and other impurities, were separated. The pure substance obtained was dried over sulphuric acid in the receiver of the air-pump, and it had then a white crystalline appearance; by subjecting it to heat, it was volatilized, and then condensed, in beautiful acicular crystals. : In the substance thus purified, there remained no traces either of chlorine or sulphur, as described by M. Julin, and it exhibited, the following properties: It burned with a strong bright flame ;. at a heat below redness, it sublimed without undergoing any change ; when passed through a red-hot green glass tube, there was;a slight appearance of decomposition, a small quantity of charcoal being deposited, and the substance became brown, but ~ * On his departure for the Continent, M. Julin left the above account, and also some: of the substance which he has described, in the hands of the Editor, with permis-° sion to make use of both as he wished. _ From the circumstance mentioned by M. Julin., of its appearing to resemble the perchloride of carbon, the substance in question was’ shown. to th gh Faraday, and with his assistance the additional experiments now described’ were made, ; BEN: 718 = On apeculiar Substance found in Nitric Acid. [Marcn, it crystallized and appeared to have suffered but little change; it was soluble in alcohol and ether, as described by M. Julin. _A portion was repeatedly sublimed ina small retort tilled with chlorme, which was in several parts made red-hot, but even at this high temperature, it suffered no change by the action of the chlorine, and when left to cool, it reappeared inits original state of small white crystals ; a minute portion was raised in vapour over aiid mixed with oxygen gas, and detonated by the electric spark ; no charcoal was separated, and we found that-an excess of oxygen had been employed. The volume of residual gas was precisely equal to that of the oxygen employed. This gas, excepting a small portion of pure oxygen, was absorbed by lime water, in which it caused a white precipitate, and conse+ quently it appeared to be carbonic acid gas. This experiment was several times repeated with similar results. . A small quantity of this substance was passed in vapour over red-hot peroxide of copper; a considerable portion was volati-+ lized without being decomposed ; the gas obtained from that part which suffered decomposition possessed the characters of carbonic acid. 3 | . The very minute quantity of the substance which remained revented any further attemp ‘to examine its nature; and the nowledge we have of the mode and circumstances of its forma- tion has not been sufficient to enable us to form it. . Although it would be premature to give a strong opinions to:the nature of this substance, yet the striking peculiarities it presents with heat, chlorine, and oxygen, have made us anxious to form some idea of its composition. We are acquainted with no eompound of hydrogen that would present similar phenomena when heated in chlorine gas, nor do any of the compounds of earbon exhibit the same results with oxygen gas. - The substance in question may possibly be a compound of carbon with oxygen and hydrogen, in the proportions required to form water, and the circumstance of there being change of volume on detonation with oxygen gas, might, on this supposi- tion, be accounted for; but it is difficult to suppose that such a compound would pass through a red-hot tube, or suffer exposure toa ved heat on chlorine gas without. decomposition. It may be allowed us to remark, in the uncertainty which we feel respecting the nature of this substance, that the appearances which it presents would agree with the idea of its being a-simple body.: m this case, it may be either a new form of carbon, ora peculiar substance analogous to carbon. We venture, however, these ideas without putting any confidence inthem, We enter- tain ee of being able to procure more of the substance, and we shall then examine its properties with minute attention, ‘ani determine the characters of the products which.it gives by deto- nation and other modes of treatment. 1821.] ‘Prof. Berzeliusien thesComposition of Prussiates. 219 ~~ “Articre XIT. Researches on: the Composition of the Prussiates, or ferrnginous Hydrocyanates. ‘By J. Bevzelius. (From. the. Annales de Chimie, vol. xv..p. 144, NewSeries:)* ) Tue discovery of cyanogen and of the composition of hydro- cyanic acid, which we owerto the genius of M. Gay-Lussac, is certainly one of the most interesting that has been made in our time, particularly since this acid is found on .the confines between those combinations which have an organic origin, and those whose origin is purely inorganic. The comparison of cya- nogen with those bodies, which become acids by their combina- tion with hydrogen, has simplified the theory of hydrocyanicacid, and of the phenomena produced by its decomposition ; but never- theless, the researches subsequent to those of M. Gay-Lussac, whose object was to throw more light on the subject, have by no means been made with sufficient care, fully to.explain the nature of the salts called. ferruginous hydrocyanates, the most important of the combinations of hydrocyanie acid. | We owe.a multitude of important observations on the nature of these salts to Mr. Porrett. He found that the hydrocyanates: can combine with sulphur, forming ‘a particular acid, whose existence, and some of its properties, were ‘known before:; -but in what the difference between this and hydrocyanic acid con sists was far from being suspected. Mr. Porretiwas led, more- over, to.conclude from his experiment, that the iron which enters into the composition of the ferruginous hydrocyanates, does not exist in them in the state: of oxide, but in its metallic form com- bimed with the-carbon, hydrogen, and azote; and that it is,:con- sequently, one of the elements: of the acid in which the iron plays an analogous part to that of the sulphur in the preceding compounds; and, therefore, an idea of the hydrocyanates being salts with.two bases, of which oxide of iron is :always.:one, is imcorrect., Several memoirs have been published on this: subject _ by Mr. Porrett, in Thomsen’s Annals, the principal ‘results «of which [ shall detail. He at first found ferruginous hydrocyanate of potash com- posed of , : Ferruginous hydrocyanic > acid »(ferru- wetted. chyazic:acid)........5. 0. A766 RAREROOe 4058 Jon.aace dass whiw.i Od MMe iildudiads o2wiekeeds atid - 100 , _ The same salt, analyzedby M . lttner, gave * Translated from the Memoirs of the Academy of Sciences of Stockholm, for the year 1819, p. 242. » 220 Profs Betzeliuson TM Anew Hydrocyanic acid............ sx slywelsh Al Hydrocyanate of protoxide ofiron ...... 38 RBOtaSh sv. seiegipinctmd ermine eininetare sem ulasein OO Water oy: onie 72H hod hte ra hinay sae 12 © Thomson, who adopted Porrett’s idea of the value of the fer- ruginous che? hr acid, examined the composition of hydro- cyanate of potash, and obtained from it the following results : ove eliighy git 13-0* w dokdie, ‘Aid iyi eh om \. prerain . 45-90" Peek 8G Se ek DES FBO TS oes 41°64 Watery C2, SE ROL We a BOE 13-00 - Dr. Thomsom states that during the decomposition of this salt by another acid, a portion of the hydrocyanate of iron is volatix lized with such rapidity that when he poured nitric acid on the pulverized hydrocyanate, the acid in the flask from which he ured it was coloured blue by the volatilized prussiate of iron. r. Thomson endeavoured to analyze the acid; by burning the salt with base of potash in the oxide of copper in a tube of the same metal. . Five grains of the crystallized salt gave 5°2U5 cubic inches of carbonic acid gas, and 2:42 cubic inches of azote, with 2:2 grs. of water, 0°65 gr. of which were derived from the water of crystallization of the salt. This experiment gave 21 volumes of carbonic acid gas for one volume of azote, exclusive of the carbonic acid retained by the alkali, of which no account was taken, nor, as far as appears, any deduction made, for the atmo- spheric acid contained in the apparatus at the beginning of the experiment. r. Thomson concludes from it, that the acid of these salts contains, besides the iron, the same elements, and in the same proportion as the hydrocyanic acid, because he ‘supposes that one fourth of the volume of carbonic acid gas, that he found in- excess, might be an error of observation, and that the quantity of water, which is four times greater than the quantity admitted by this supposition, was derived from the corks with which the Opening of tle copper tube was closed, so that its hygrometrical water might have mixed with the products of the analysis. However when Thomson made his calculations from the results, and distilled the carbon and hydrogen, which did not coincide with the theory, the weight of the iron did not accord with the chemical proportions. ‘* This,” he says, “ is the first compound which I have met with that does not seem reconcileable to the atomic theory. 1 invite chemists to the further investigation of it. There are no facts so likely to lead to the improvement.of the science of chemistry as those which contradict our received = Go ta the French. 1821.] . the Composition of Prussiates, 221 opinions,” * to which it appears to me he should have added, «« with the exception of those cases in which the discordance is the result of an ill-made, incorrect experiment,” whenever the science derives a truly negative advantage. Mr. Porrett also soon endeavoured to prove Thomson’s analy- sis inaccurate. He, on this occasion, analyzed the salt of potash by a solution of tartaric acid in alcohol, and determined the quantity of potash by the supertartrate of potash produced. The following is the result of his analysis : Ferruginous hydrocyanic acid. ...... 50°93 EOUSO oc. ss Siete eR Se .. 00°48 He had found that the ferruginous prussic acid might be insu lated by this operation, and that it gave cubic crystals by spon- taneous evaporation. In an analysis of this salt by oxide of copper, he obtained four volumes of carbonic acid gas for one of azote; whence he concluded that the acid is composed of one atom of azote, four atoms of carbon, one atom of hydrogen, and one atom.ofiron. He attributed the deficiency of carbonic acid in Thomson’s results to his having employed too small a propor- tion of oxide of copper. Lastly, Mr. Porrett published a further memoir on this subject, in which he again corrected his former results as follows : Gas .. 32°72 _Ferruginous hydrocyanic acid {ion 12.60 y 45°32 BRAIN 5 ones ints anh oie Repeating the experiment of burning the salt with oxide of copper, he constantty obtained four volumes of carbonic acid gas for one of azote; whence he concluded that the acid is com- osed of four atoms of carbon, one atom of azote, one atom of fiydropen; and half an atom of iron ; but this half atom of iron not being consistent with the atomic views, he conceived his experiments to be sufficiently exact and positive, to decide, con- trary to conclusions derived from less complicated and easier experiments made directly on iron and its oxides, that the weight of the atom of iron is not half what it has heretofore been admit- ted to be, or one-fourth of that laid down in my tables ; whence he concludes that the protoxide of this metal is composed of two atoms of base and one of oxygen, and the deutoxide of four of base and three of oxygen. M. Vauquelin also made many researches on the prussiates ; and his treatise on the subject is full of interesting facts; but he did not employ himself in determining the proportions of its elements, which is the principal object of the present memoir. He found that prussian blue, contrary to what Gay-Lussac had. * Annals of Philosophy, vol, xii. p. 112, 222 Mr. Perkins on the Compressibility of Water. [Mancn, endeavoured to render probable; is a prussiate, and not a cyanu- ret. Vauquelin thought, moreover, that he had discovered that those bases capable of decomposing water at the common tem: perature of the atmosphere give hydrocyanates, while the others give only cyanurets. | The last work on this subject that has come to.my knowledge isa note by M. Robiquet on the composition of prussian blue. Ir it he confirms the results which M. Proust had derived from his experiments on the prussiates, made long’ since, and among others this, that the white prussiate of iron contains potash. M. Robiquet showed that this prussiate without potash may be obtained in the form of small crystalline grains, of a yellow colour, by exposing prussian blue for a long time to the action of sulphuretted hydrogen gas. He considers. prussian blue: as a combination of cyanuret of irom with a: prussiate of deutoxide: of iromand water; and he attributes its blue colour to water. He asserts that ferruginous prussiate of potash burned by means.of oxide of copper always afforded him the gases in the same pro+ portion to one another that Gay-~Lussac found them in cyanogen; and he maintains that im this experiment the base retains no carbonie acid, as Mr. Porrett had. noticed. Results so contradictory, and conjectures; so little justified by experiment, are not very well calculated to give us an exact idea of-the:composition of these salts; and although the path has been marked out by the labours of Gay-Lussac, we must confess, in spite of what has been done with him, that we-are just at the same point at which he left the question. M. Proust long ago proved the ferruginous prussiates to. con- tain iron, and that they must be regarded as salts with double bases, of which the protoxide of iron is always one, exactly as alumina is-always one of the bases.in the different kinds of alum; and, he showed that prussiam blue must be a hydrocyanate im which the deutoxide of iron represents the other bases. with the protoxide. Mr. Porrett’s:idea that. the iron: is an: element of the acid’ has always appeared to me analogous. to that,of considering the pot- ash in, cream of tartar as an element of the acid in pel. de,sing- nette, or tartar emetic.. . Yor y (To be. continued.) ARTICLE XIV. On the. Compressibility of Water. By Mr. Perkins. (To the Editor of the Annals of Philosophy.) SIR,, Feb. 23, 1821+ In. the Annals of Philosophy for February, Dr. Roget has discovered a very material error in my computation on the first experiment made! withthe: piezometer: om the» compressibility of 3821.) _ Analyses of Books. 293 water) The real error was’ in the data being incorrect in the paper «read: before the Royal Society. The dimensions: of the iezometer should have been as follows : : -| “Therdiameter of the cylinder 345, inches, length 233 inches,’ the plunger ~9, diameter. The mistake originated by taking the dimensions of a bathometer which was used at the time the experiment was made. | , ‘With much esteem, yours truly, | Jacos Perxrns. ARTICLE XY. ANALYSES OF Books. Pharmacologia, or the History of Medicinal Substances, with @ View to establish the Art of prescribing and. of composing extemporaneous Formula upon fixed and scientific Principles; illustrated by Formula, in which the Intention of each Element is designated by Key Letters. By John Ayrton Paris, MD. FES. MRI. &c. &c. | Ir this:publication were entirely medical, it would of course be improper to notice itm a work professedly scientific ; but as it involves considerations, and to a very considerable extent, which belong to: the science of chemistry and the operations of phar- macy, | conceive that some account of it may not be misplaced in: the Annals. | Dr. Paris. has prefixed to this work an “ Historical Introduc- tion,” giving an account of the more prominent revolutions that have occurred in the reputation of medicinal substances; and in the execution of this task, he has deviated from the beaten path, and has given an air of originality to a subject which might be considered as “* somewhat musty.” This history will be found, tovuse the author’s own words, “ an analytical mquiry into the more remarkable causes. which have, m different ages and coun- tries, operated in producing the revolutions that characterise the kustory of medicinal substances:” it will be impossible to read this introduction without fully assenting to an opinion expressed by'the late Dr. George Fordyce, that whenever a substance was good for nothing else, it was tried in medicine. “ The revolu- tions and vicissitudes,” says the author, “ which remedies have undergone in medical, as well as popular, opinion, from the igno- rance of some ages, the learning of others, the superstition of the weak, and the designs of the crafty, afford an ample subject for philosophical reflection ; some of these revolutions I shall proceed to investigate, classing them under the prominent ccuses which have produced them; viz. Superstition—Credulity— 224 Analyses of Books. — [Marcon, Scepticism—False theory—Devotion to authority and esta- blished routine—The assigning to art that which was the effect of unassisted nature—The assigning to peculiar. substances properties deduced from experiments made on inferior animals —Ambiguity of nomenclature—The. progress of botanical science—The application and misapplication of chemical philo- sophy—The influence of climate and seasons on diseases, as well as on the properties and operations of their remedies—The ignorant preparation or fraudulent adulteration of medicines— he unseasonable collection of those remedies which are of vegetable origin; and the obscurity which has attended the operation of compound medicines.” Now to this truly formidable list of mischief-producing causes, I think the author might have added, the careless revision of national Pharmacopeeias ; unless this may be classed under the head of the ignorant preparation | of medicine. | Under the head of “* Ambiguity of nomenclature,” Dr. Paris has collected some curious facts, and from such various sources, ‘as to evince that his reading has been extensive, and that he has neglected no means of attaining knowledge in illustration of his subject. After mentioning some circumstances respecting the sweet and common potatoe, he observes, “ A similar instance is. pre- sented to us in the culinary vegetable, well known under the name of Jerusalem artichoke, which derived its appellation in consequence of its flavour having been considered like that: of the common artichoke ; itis hardly necessary to observe that it has no botanic relation whatever to such a plant, it being an heliotrope (heliotropium tuberosum); the epithet Jerusalem is a curious corruption of the Italian term gira-sole ; that is, turn-sun in English, or heliotrope in Greek.” Dr. Paris. occasionally enlivens the subjects on which he is treating (and it must be confessed that they sometimes stand in need of it) with anecdotes which happily illustrate his positions: he remarks, that ‘it ought not to be forgotten that cultivation and artificial habits may have blunted the susceptibility of our organs, and in some instances changed and depraved their functions: certain qualities, for instance, are so strongly con- nected with each other by the chain of association that by pre- senting only one to the mind, the other links follow in succession. This might be illustrated,” continues. Dr. Paris, ‘* by the recital off numerous fallacies to which our most simple perceptions are exposed from the powers of association ; but I will relate an anecdote which, to my mind, elucidates the nature and extent of such fallacies more strikingly than any example which could be adduced. Shortly after Sir Humphry Davy had succeeded in decomposing the fixed alkalies, a portion of potasstum was placed in the hand of one. of onr most distinguished chemists, with a query as to its nature? The philosopher, observing its , 1821.) Dr. Paris’s Pharmacologia. 225 aspect and splendour, did not hesitate in pronouncing it to be metallic, and, uniting at once the idea of weight with that of metal, the evidence of his senses was even insufficient to dis~ sever ideas so inseparably associated in his mind, and, balancing the specimen om his fingers, he exclaimed, ‘ [t is certainly metallic, and very ponderous!’” Now this anecdote is not related in disparagement to the philosopher m question, Who could have been prepared to meet with a substance, so novel and anomalous, as to overturn every preconceived notion? & metal so light as to swim upon water, and so inflammable as to eatch fire by the contact ofice! 7 . In the same strain it is further and happily observed by Dr. Paris, when treating of mercury, that “ mythologists inform ug that he was the winged messenger of the gods, and the patron of thieves. What name, therefore, could be more appropriate for the metal in question than that of this deity? for it is not only distinguished from all other metals by its mobility, but its universal agency has rendered it: the resource of those worst of thieves—quacks, and nostrum-mongers.” Dr. Paris, in addition to his own experience, and to the information gained by his reading on the subject, has obtained much useful information from persons in distant countries respecting the influence of soil, culture, climate, and season: for particulars, | must refer the reader to the work itself. : . , The only remaining part of the historical introduction which I shall notice, is that which treats of the application and misap- plication of chemical science. ' In the beginning of this section, some very amusing and curious matter will be found. After noticing the works of Roger Bacon, Basil Valentine, Paracelsus; Van Helmont, &c. he comes. down to ovr’ own times, and honours, first, Mr. Brande, aud then me, with some notice for the €riticisms which we have occasionally ventured to make upon the London Pharmacopeeia; and | believe I may regard myself, with- out any undue pretensions, as a very prominent member of a new order denominated, by Dr. Paris, “ Ulira Chemests;” and 1 am accused of exhibiting, in my Experimental Examination of the Pharmacopeeia Londinensis, a “ caustic style of criticism,” rather than ‘“ any fatal or material inaccuracy” im the work reviewed. Great allowance is to be made for Dr Paris, in passing his judg- ment upon my examination, for he is a Fellow of the College; but still not having been so at the time when the Pharmacopeeia in question was edited, I think he would have shown more discre- tion in suffering it to sleep quietly in the dust to which the Col- lege have consigned it. {Lam not so good a judge of the ap- earances which indicate what is “fatal” as the Doctor; but, ithink,, if he should find that a person was utterly incapable of performing any of the funetions which indicate vitality, he would conclude him to be dead. If then I discover in a Pharmacopceia atartarised antimony which is not tartar emelic, and consequently incapable of answering the end for which it was prepared, I have New Series, voL.1. P 226 Analyses of Books: = =~ [Marcn, grounds for concluding that I have pointed out “a fatal and mate- rial inaccuracy.” Indeed the College seem to have concurred with me on this point, for the process of which | complained has been abandoned. Whether that which is substituted for itis any better, | need not on the present occasion inquire. To proceed, however, with that part of the work which it is more important to notice, it is to be observed, that after the his- torical introduction, we have the term ‘ Pharmacologia’ defined, as comprehending “the scientific methods of administering medicinal bodies, and explaining the object and theory of their operation.” This is divided into two parts; ‘ the first compre- hending the principles of the art of combination, and the second the medicinal history and chemival habitudes of the bodies which are the subjects of such combination.” 7 Excepting a short and incomplete paper by the late Dr. George Bondy oes I believe no attempt bas before been made to investigate the medicinal properties resulting from the mutual action of bodies independently of their chemical action. In the execution of this part of his subject, the author has developed some original views which appear to be capable of application to the chemical analysis of vegetable substances. Thus in men- tioning senna, he observes, that its leaves ‘‘ appear to contain an active principle in combination with a bitter, which latter ingredient, although destitute of purgative properties, considera- bly increases those of the former; for if this be removed, as happens when senna is transplanted into the south of France, the purgative principle is weakened, but may be again restored by the artificial addition of some bitter extractive.” This and similar instances induce Dr. Paris to inquire whether it does not appear that ‘“ certain elements exist in the composition of vege- table remedies as furnished by nature, which, although indivi- dually inert, confer additional strength and impulse upon the principle of activity with which they are associated ?” Incurring the risk of being again deemed an ‘ Ultra,’ I shall venture to observe that this reasoning appears to be derived from the well-known chemical fact, that it 1s impossible to dis- cover, a priori, what will be the result of mixture; and I am apprehensive that the few remarks which I intend to offer upon the formule introduced by Dr. Paris, will be considered as irrelevant. | It will be seen by referring to the work that “ key letters,” so denominated, are placed opposite to each ingredient of a collec- tion of formule to denote the mode in which it acts. Now although these formule appear in general to be extremely well composed, there are, I think, some instances in which the idea of the mutual assistance of similar medicines is carried a little too far. On this subject I confess I speak chemically and theoreti- cally ; but ] would ask, what is tiere so different in the action of oak bark, galls, and catechu as astringents, that a mixture of them is preferable to any one, or at any rate any two of them; 1821.] Proceedings of Philosophical Societies. oe but these three substances are employed together in one for- mula. It is indeed true that the oak bark is used in the state of an infusion, the galls in that of powder, and the catechu in the form of tincture; but as all of these bodies may be used in any of these forms, I cannot conceive the utility of using them all together But this is, perhaps, the natural result of my being an “ Ultra.” Dr. Paris appears to have paid considerable attention to a subject of great importance: I allude to the methods of detecting the presence of arsenic; and he has pointed out, not only the methods by which it may be discovered, but has mentioned many circumstances which give rise to ambiguous appearances of its existence. In addition tothe copper and silver tests, upon which he ‘appears to place the greatest reliance, I would beg to suggest the additional evidence which may be easily and _strik- ingly obtained by the use of an aqueous solution of sulphuretted hydrogen gas, with an aqueous solution of the suspected sub- stance. Itis, perhaps, scarcely necessary to observe, that the effect which results from their mutual action is the production of a yellow-coloured solution without any precipitate. From recent experiments, [ am satisfied that arsentous acid possesses no allia- ceous smell, and that it is peculiar to the arsenic volatilized in its metallic state. I mention this circumstance, because different opinions appear to be entertained on the subject; and if the arse- nious acid be not heated under such circumstances as decom- pose it, a ready but rough method of detecting the presence of arsenic may be rendered useless. é As one of the not least useful parts of Dr. Paris’s work, I ma: notice his exposure of quackery, and the statement which he has. given of the composition of more than 100 of the most cele- brated, and consequently the most mischievous, quack medicines. In concluding this notice { may observe that with respect to those parts of this performance of which [ may be sup- posed to be able to form an opinion, that opinion is highly favourable ; and although the work is evidently intended to afford pharmaceutical and pharmacological information to the junior members of the medical profession, there are many of a maturer‘age who may receive much benefit from its perusal ; and - it will form a useful addition to the medical library. — kd. ArtTicLeE XVI. Proceedings of Philosophical. Societies. ROYAL SOCIETY. Feb. |.—The Bakerian lecture on the best Kind of Steel, and Form for a Compass Needle, by Capt. Kater, was read. P2 \ ; 228 Proceedings of Philosophical Societies, [Marcnj _. £eb. 8.—A paper was read, on the Fossil Bones: found in the Limestone Rock at Plymouth, by Mr. Whidby. At the same meeting, a paper, by Dr. Henry, of Manchester, was partly read, on the Aeritorm Compounds of Charcoal and Hydrogen, with some additional Experments on the Gases from Qil and Coal, if Feb. 15.—The paper, by Dr, Henry, on the Aeriform Com- pounds of Charcoal and Hydrogen, was resumed. | At the same meeting, a paper was read, by the Rev. Dr. Robertson, entided, “ Observations of the Echpse of the Sum on Sept. 7, 1820.” ) At the same meeting also a notice was read, respecting a lunar Volcano, by Capt. H. Kater. | 3 Capt. K. first observed. this voleano on Sunday, Feb. 4, the moon being then two days old; its appearance was that of a small nebula, of variable brightness, subtending an angle of 3” or 4”, [ts distance from the edge of the moon was 1-1 Uth her: diameter ; and on the 6th, the angle it formed with a line jom-~ ing the cusps was about 5U°.. | ) rs _ #eb, 22.—Dr. Henry’s paper, on the Aeriform Compounds: of Charcoal and Hydrogen, was concluded. | | | The object first proposed by the author was to examine the: accuracy of those views of the compounds of charcoal and hydro» gen which had arisen out of his former experiments, and those of: r. Dalton, especially, whether there be a compound answering in; its characters to light carburetted. hydrogen gas, the existence: of which had been called in question in alate Bakerian lecture. This, after attentively, and at various times, examining the gas! from stagnant water, he pronounces to be a distinct chenncal compound, having uniformly the same composition and chemical. properties, and the same specific gravity (U°556). It is consti- tuted of 100 parts by weight. of charcoal united with 33°40 of hydrogen; while oletiant gas consists of 100 charcoal + 16°70: hydrogen. Hence if the latter be considered as a compound. of one atom of charcoal and’ one atom of hydrogen, carburetted hydrogen must consist of one atom of charcoal and two atoms of hydrogen; and as 100 eubic inches of carburetted: hydrogen contain hydrogen equivalent to.200 cubic inches of hydrogen gas, he suggests the verification of the specific gravity of hydrogen gas by that of carburetted hydrogen, and finds that in this way it comes out 00698, making the relative weights of the atoms of hydrogen and oxygen bi nearly as 1 to 8. The atom of char- coal also he estimates from.the composition of carburetted hydrogen, and of carbonic acid, at 6. 84 His next experiments relate to the best means’ of analyzing mixtures of olefiant gas with hydrogen, carburetted hydrogen, or carbonic oxide; and of olefiant gas with all those three gases. Chlorine, he shows, may be employed with: perfect accuracy, provided certain. precautions are observed, wich are) described »~ ¥821.} | — ‘Rayal Society. 229 at length in the paper. The chief of these is the complete exclu- ‘sion of light, for in that case olefiant gas alone is condensed, but veven the faint light of a cloudy day was found sufficient to cause ‘the speedy action of chlorine on the other gases. The paper contains also ‘directions for analyzing mixtures cf hydrogen, car- ‘buretted hydrogen, and carbonic oxide, but these, from their mature, are incapable of abridgment. By the analytical processes thus established, he proceeds to “examine the composition of oil gas and coal gas.~ ‘The results ‘are given in tables, but the general issue of the experiments is ‘that oil eas (as he had formerly shown with respect to coal gas) is very far from being uniform: in composition, but differs greatly in specific gravity and combustibility, when prepared at different ‘times even from the same kind of cil, owing to variations of temperature and other circumstances. Essentially the gases from oil and from coal are composed of the same ingredients, though in different proportions, viz. simple-hydrogen, light car- buretted hydrogen, and carbonic oxide gases, with the addition of variable proportions of an elastic fluid, which agrees with ole- fiant gas in bemg condensible by chiorine, but consumes more oxygen and gives more carbonic acid, by combustion, and has a higher specific gravity than olefiant gas, and eyen than atmo- spheric ai. Whether this ingredient be strictly a gas, perma- nent at all temperatures, or a mixture of olefiant gas with some new gas, constituted of hydrogen and charcoal in different pro- portions from what are found in the known compounds of those elements, or merely the vapour of a volatile oil, he leaves to be decided by’a future train of experiments, : CAMBRIDGE PHILOSOPHICAL SOCIETY. Address read at the First Meeting of the Cambridge Philosophical _ Society, stating the Design and Objects of its Institution; writien at the Request of the Council, by Edward Daniel _ Clarke, LL.D. Professor of Mineralogy in the University of Cambridge, &c. 3¢. Avr the opening of the first meeting cf the Cambridge’ Philo- sophical Society, the Members of the Council avail themselves of the earliest opportunity that has been offered to them, of expressing to the Society their congratulations upon its Institu- tion.’ Convinced, as they all of them are, of the advantages likely to result-from the establishment of sucly a Society, they do not hesitate to declare their opinion, that. an event of more importance, as affecting the, best interests of science, has rarely eceurred in theannals of the University. A century has now elapsed since the celebrated Woodware — petaed the following axiom.to-his ‘‘ Essay upon the Natural listory of the Earth,” which took the lead in subjects of geclo- gical inquiry. “‘From’a long ‘train of experience,” said he; 230 Proceedings of Philosophical Societtes. [Manrcn, “the world is at length convinced that observations are the only sure grounds, whereon to build a lasting and substantia! philo- sophy. All partyes are so far agreed upon this matter, that it seems to be now the common sense of mankind.*” For this reason, when he composed his work, as he himself states, ‘‘ He gave himself up to be guided wholly by matter of fact, intending to steer that course, which is agreed, of all hands, to be the best and surest ; and not to offer any thing but what hath due warrant from observations.+ Unfortunately, for the fame of this distin- goahed naturalist, and for the University to which he bequeathed is valuable collection, the want of a Society affording the means of philosophical communication, caused his immense treasure of facts to remain hoarded in a place by no means wor- thy of the collection, or convenient for its arrangement. Hence the hardly credible truths which are now beginning to come to light respecting the Woodwardian collection ; hence the extraor- dinary circumstance, first made known by the late Professor, the Rev. J. Hailstone, that the corundum stone (a substance of such singular utility in the arts, and whose supposed discovery, as distinguished from other minerals, was attributed to Dr. Black, of Edinburgh), was not only known to Woodward, but specimens of it existed unnoticed in his cabinet many years before Dr. Anderson, of Madras, sent to Europe the examples upon which Dr. Black founded his observations. The same may be said with regard to other bodies, and especially that remarkable sub- stance called the native meteoric iron of Pallas, also in the Woodwardian collection.{ To obviate even the possibility of . such occurrences in future, to lay open. channels of communica- tion for facts connected with the advancement of philosophy, and also to bring together men who are engaged in common pursuits of science, is the main object of the Cambridge Philosophical Society. The zeal and promptness which have been manifested in its establishment, and a view of the names which have been already added to the list of its members, excite a reasonable hope that, by means of it, a fund of valuable information may be adually accumulated. Some idea may be formed of the use- ulness of such an Institution, simply by referring to the various eriodical Journals, edited, either by individuals, or by societies, an different districts of this kingdom; in which the philosophical * Nat. Hist. of the Earth, p. 1. Lond. 1723, . + Ibid. ‘+ The observations I speak of,” observes the same Author, p. 3, ‘* were all made in England, the far greatest part whereof I travelled over on pu to make them ; professedly searching all places as I passed along, and taking a ul and exact view of Things on all hands as they presented ; in order to inform myself of the present condition of the earth, and all Bodyes contained in it, as far as either Grottos, or other Natural Caverns, or Mines, Quarries, Colepits, and the like, let me into it, and dis~ played to sight the interior parts of it.” “i + To prove this remarkable fact, Professor Hailstone purchased a specimen of the native meteoric iron of Pallas, and placed it in the Woodwardian collection by the side af Woodward's specimen, that their identity might be the more easily recognized. 1821.) Cambridge Philosophical Society. 231 contributions of the members of this University, being frittered and squandered away in detached and distant parts, appear to be almost without existence; but if the same scientific productions had been concentrated, their testimony of the industry and abi- lities of their authors would not only be creditable to the Univer- sity, but would also tend more effectually to the advancement of Science. It is one of the objects of the Society, that a volume for giving publicity to such writings, should occasionally be sent forth, not at any fixed or stated periods, but so often as due and approved materials can be selected for this purpose, and to this end it is proposed that Philosophical Communications should be encouraged from every quarter likely to afford them, by render- ing to their authors every possible assistance which may be necessary for their publication. Letters have been already transmitted from the Secretatics to persons who are likely to promote the intentions of the Society ; and it is requested that all its members will themselves further the designs of the insti- tution, by inquiring for communications relating to the several branches of natural history, and natural philosophy, especially by means of their foreign correspondence, and the observations they may be able to collect from scientific men engaged in foreign travel. Whatsoever may tend to illustrate the history of the animal, the vegetable, or the mineral kingdom ; of organized or of unorganized existences ; will be deemed valuable acquisitions. Of course, it is hardly necessary to add, that all papers on the subjects of zoology in all its branches ; of botany, mineralogy, geology, chemistry, electricity, galvanism, magnetism, and all mathematical communications connected with the subjects of natural philosophy, will be thankfully received, and always duly acknowledged. The want of a sufficient incitement towards inquiries of this nature, after University students have commenced graduates, has been sometimes considered as a defect in the scheme of University education. At that important period of life, when the application of philosophical studies should begin, academical students seem to have acted under an impression that they have brought their studies to a termination. Or, if a disposition should prevail, to approach the studies of Nature, under the conviction that it is better “ de re ipsa quarere, quam mirari,*”” this tendency, of such incalculable value in youthful minds, becomes checked, either by the retirement or consequent want of intercourse with literary men, to which the calls of professional | duties consign them,or by the little honour which inall ourUniversi- ties has hitherto awaited the inquiry. ‘The valedictory observa- tions of Bishop Watson afford a decisive confirmation of this truth: + and the reproaches cast upon our country by the cele- brated Kirwan { may be still considered as not altogether inap- - a Seneca. ++ Watson’s Miscellaneous Tracts, vol, ii. p. 438. Lond, 1815. _ + Min. Pref. p. 1. Lond, 1784. Od, Jaatond cca 232 Proceedings of Philosaphical Societies. [Maren, plicab'e. “ In Sweden and Germany,” sayshe, “ mineralogy is considered as a science worthy the attention of government, There are Colleges in which it is regularly taught; it forms a distinct and honourable profession, hike that of the soldier, ‘the meichant, or the barrister; its superior cflicers form a part of the administration of the state. Young students fraught with the knowledge to be acquired in their own country are sent abroad to glean all that can be collected from a more diversified view of nature. This example has been followed by France, Russia, and Spain. -Chemistry too, the parent of mineralogy, is cultivated by the most enlightened nations in Europe, and partis cularly in France, with a degree of ardour that approaches ‘to enthusiasm, In England, on the covtrary, it receives no encous ragement from the public.” .These observations which that emment naturalist then applied to the studies in which he was more particularly engaged, may, to a certain extent, be yet directed towards every other branch of natural philosophy. In the posthumous works of Dr. Hooke, which were dedicated to Sir isuac Newton, when he was President of the Royal Society, by its Secretary Waller,* we find their acthor maintaining, that the neglect shown to natural philosophy has beeu characteristi- eal, nct of this country alone, but of all nations and in all ages. “* Learned men,” he complains, ‘ take only a transient view of natural philosophy in thei passage to other things; thinking # sufficient to be able to talk of it in the phrase of the school. Nor is it only so now, but it has been so almost in all ages; so - that for about 2000 years, of which we have some account ap history, there is not above one quarter of that space in which men have been philosophically given ; and among such, as have ‘ been so, several of them have been so far disjoined:by time, lane guage, and climate, by manner of education, manners and epiions, and divers other prejudices, that at could not be ‘expected it should make any considerable progress.” Vet the effect of such studies upon the mind, and PO — appropriated to public education, and in an age when Ise philosophy and irreligion have been so alarmingly mani+ fested, may perhaps secure for them a more favourable receptions silice it requires no argument to prove that the evidences of reli- gion always keep pace, and are progressive, with the discoveries im natural knowledge. After a long life entirely devoted to the studies of natural history, Linneus placed over the lintel of the door of his museum an inscription which was calculated to con- wey to the mind of every approaching student a conviction of this truth; Innocue vivito! Numen adest ! + Having thus set before the Society the main design and objects _s Hooke’s Present State of Netutal Philosophy ; see Posthumous Werks, p- ‘Bee Linnens's Diary written himself, in Pulteney’s Linnzus by Maton, BOS Lond 1005, : ” vc Manalaod aenraaeet 2821.) — Scientific Intelligence. 238 af its Institution, the Councii beg to eall the attention of this meetine to considerations of a subordinate nature. It willbe necessary to provide some place in which the future ora may be held, and where a repository may be formed for the reservation not only of the archives and records of the Society. Lurates of such documents, books, and specimens, of natura’ ‘history, as may hereafier be presented or purchased. |The mtmost economy will at present be requisite in the management of the Society’s funds; and, therefore, if the consent of -the University: could be obtained, it would be highly desirable that the expenses of printing the Society’s Transactions, shouldbe defrayed by the University.* His Royal Highness the Chancellor has accepted of the office of Patron, and his letter, containmg the expression of his approbation, will be read by one of ‘the Secretaries. The present Vice-Chancellor, our High Steward, both our representatives in Parliament, and many other distin- guished members of the University, who are not resident, have ‘also contributed towards the undertaking ; and there is, there- fore, every reason to hope, that the Graduates of this Uni- versity, who associated for the Institution of the Cambridge Philosophical Society, by their assiduity and diligence in its support, and by their conspicuous zeal for the honour and well- being of the Chicemity : will prove ‘to’ other times, that their lives and their studies have not been in vain. . Articte XVII, SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS. CONNECTED WITH SCIENCE. 4d, Notice of some new Minerals from Finland. By M. Julin, of Abe. ‘As any information contributing to promote the knowledge of minerals will probably be agreeable to your readers, I submit to your disposal a brief notice of an investigation, made by Mr. N. Norden skiéld,¢ of the crystalline form and the chemical constituents of several Finnish minerals, among which the most recently discovered -are ¥vamanzorit and pyrallolit. | ee | » Romanzovit.—M. Nordenskiéld ‘has named this new mineral after Count Romanzoff, who is well known to, promote scientific pursuits In eneral, with unbounded liberality, and whose attention and generosity in particular, contribute to investigations relating to the mineralogy, language, and history of Finland. kre: * This is now done. ‘ | ‘+ Mr. Nordenskiold is a Finland gentleman, a pupil of Berzelius. ‘He published hia fesearches a few months since in a pamphlet, entitled, ‘* Bidrag till narmare Kannedo af Finlands Mineraligi or Geognosie,” from which this communication is an extracts 234 Scientific Intelligence. [Marca, This mineral is found in the lime quarry of Kulla, at Kimito, in Finland. The colours of this mineral are brown, brownish-yellow, and blackish-brown, It occurs compact, sometimes in crystalline planes, which indicate the rhomboidal dodecahedron with replaced edges : there seldom occur more than one perfectly crystallized plane with parts of the others, they incline at an angle of 120° to each other. The fracture is small, conchoidal, splintery, and strongly resembles that of common resin. The crystalline planes are highly splendent; the crystalline transi- tion planes sometimes shining, sometimes dull; the lustre is greasy. When broken of the fragment, have a lustre between the vitreous and resinous ; when thin, they are translucent. | Hard; brittle; give sparks with the steel: scratch glass and feld- spar, but are scratched by quartz. The specific gravity of this substance is 3°6096 at 60° Fahr. It is of light-yellow when powdered. It ed without effervescence in the interior flame of the blow-pipe, iving a button of the same colour as the mineral, except when the me is smoky when it is blackish, : Five grammes analyzed in the general way by fusing with carbonate of potash and dissolving in muriatic acid, yielded SOR ois oni dis bie aieap 6 svieb swiss gv be 41°24 RA A ays helinn aie oitas eset 24°76 Pas ie sin din sas Miiare 9 eobiine 24 08 Oxide of iron..... Ht PRET He OPP _ 7:02 Magnesia and oxide of manganese. 0°92 Volatile parts, and loss.......... 1°98 Neither the magnesia nor the oxide of manganese appear to belong « to the chemical constituents. The oxygen in the lime is three times; the oxygen in the alumine five times, and the oxygen in the silex nine times the quantity of the oxygen in the oxide of iron, the mineralogical formula of course willbe = FS +3C5+4+5AS8,or(FS5+2AS5S, +3(CS+ AS). : , Pyrallolit.—A new mineral belonging to the tale family. Among the minerals found in the lime-quarry of Storgard in the point of Pargas, there is one, which at first was considered to be erys- tallized talc. It has the singular propensity of blackening before the blow pipe at a low red-heat, and it afterwards becomes white at a higher temperature. It occurs in opaque sparry limestone accompa- nied with feldspar, augit, skapolit, moroxit, and sphene, and particu- larly crystallized with augit, which mineral often thinly covers it. His Excellency Count Steinheit who has examined the quarries of Parga with the greatest care; and to whose zeal the mineralogist is indebted for the discovery of most of the new Finnish minerals, was also the first who gave attention to.this mineral. This mineral is found in crystalline masses, and in distinct crystals of four varieties of form. In quadrangular prisms, of which the angles are 94° 36! and 85° 24, and which are, therefore, slightly rnomboidal, the opposed lateral planes, two and two, differ in breadth ; the plane Mand its opposite plane pie V), fig. 9, being much broader than T and its opposite plane. on M 140° 49/. , 1821.] Scientific Intelligence. | 235° - Fig. 10 differs from fig. 9 only by the addition of the little planes n : non T 131° 30! Fig. 11, Pond 129°11'. The plane P isat right angles to the axis of the prism. Fig. 12. In this, the planes 7 of fig. 19 are seen in combination. P and / of fig. 11. » on P:138° 30’. The crystals seldom occur perfect; they vary ‘x. »'ze from very small to the length of 1 and 2 inches, 3-10ths to 4-l10ths of an inch in breadth. The colour is sometimes greenish. By long exposure to air and light, the coloured crystals become perfectly white. Their surface is dull. The lustre greasy. Fracture, dull-earthy. ‘Trans- lucent only when in thin lamine. The crystals are more or less cohe- rent: some readily crumble, and are then unctuous to the touch; others are harder, yielding to the knife but not to the nail, and feel then harsli in the fracture. The same crystal is sometimes hard in one end, an:! not atthe other. It seems to harden in the air. By fracture three-sided prisms are very easily obtained. Its specific gravity is 2°555 to 2594. The powder put upon a red-hot spoon phosphoresces with a bright bluish light. ; : When heated with the blow-pipe at a little below a red heat, it becomes blackish, and by continued exposure to this heat, it is ren- dered white, swells, and melts at the edges into a white enamel. It melts with borax readily into a clear glass, which, by adding a little nitre shows traces of manganese. . A little of the phosphate of soda, or ammonia added to a button of borax, saturated with the mineral, renders it after cooling an opaque and white enamel. A little' piece of the mineral heated with glass of phosphorus effervesces slightly at first, but they eventually combine. : With soda it melts to a clear glass; with a yellowish-green tinge, » the colour is most easily distinguished upon white paper. The analysis, which was conducted in the usual mode, viz. by heat- ing the fine powdered mineral with three times its weight carbonate of potash, dissolving it in muriatic acid, gave SHICA.. Kae -newatean asl de 97|_E Bos 30-291 38 | 32. | — 78 98} S_ 30°29 30 25) 35 30 _ 84 29S E 30:29 30:20} 45 | 30 — 90 30S W30°36)30-22} 50 | 42 | — 94 31/8 W303830°36) 51 4.4, 35 $4 a: nn ¥ '$0°70|29'04| 52 22 60 | 2°89,100—56! The observations in each line of the table apply to a period of twenty-four hours, beginning at 9 A. M. on the day indicated in the first column. A dash denotes that the regult is included in the next following observation. 240: Mr. Howard's Meteorological Journal. [Mancu, 182%. REMARKS. First Month.—\. A strong cold wind. 2—4. Cloudy: bleak. 5. Morning fine: about two inches of snow in the evening, followed by hail and rain, which thawed nearly all of it before morning. 6. Cloudy: the thaw continuing. 7. Cloudy. 8. Fine: cloudy. 9. Foggy. 10. Foggy: cloudy. 1. Rainy. 12. Rainy: fine at intervals 13. Cloudy: very rainy night. 14. Rainy day: a lunar corona in. the evening. 15, 16. Cloudy: fine at intervals. 17—20. Cloudy. 20. Cloudy: a lunar. corona in the evening surrounded by a largehalo. 21. Foggy morning: very fine days 22. Gloomy: fine. 23. Fine. (The observation on the barometer here given is from the one which is constantly registered. ‘Two others, probably less perfectly adjusted, were found to stand respectively at 30°45 and 30°96 inches; the clock barometer at Tottenham gives the maximum at about 30°78 inches; the whole at noon on the 23d.) 24. Gloomy: foggy. 25. Ditto. 26. Cloudy. 28. Ditto. 25. Foggy: misty. 29. Fine clear morning: fine day. 30, 31. Fine. ¥ RESULTS. Winds: N, 1; NE, 4; E, 9; SE} 3; S,23 SW,7; W, 33 NW, I; Var. 1. Barometer: Mean height | For the month... ......eeeseees ch esiceesececspeene- S000 inched. For the lunar period, ending the 26th. .s....6.0+0..+6 29:837 For 13 days, ending the 8th (moon southy. .......... 29°668 For 14 days, ending the 22d (moon north). .....++.,. 29893 Thermometer: Mean height | For tho maesihi. ds sididievsls wide » Hick dichitealln ns, MEMMRE® For the lunar period ,...¢seccceacsccevcreserccesccers SO'SSS For 30.daysy thé sutiin Onpricarn j.csedeoevonsci-.- SGI6 Evaporation. ......+s0se0 eereeee of nabs n@pa oo tienaerien eapiaine 0:60 in. Beltier o< pacdhane nu . cils nehds thn sant rat Senne 39 SONG, OM: oi iin monn lattion an die 36 EN a vament ec taiter chcavesitl accillanl eesti te Hep yred) 100 I must confess I had some doubts as to the correctness of this analysis, for on comparing it with that of the sulphate of strychnium by Pelletier and Caventou, and that of sulphate of picrotoxium by Boullay, and my own analysis of sulphate of morphium, it appears that all these three alkaline substances are very low in saturating power ; while the atropium would, accord- ing to my analysis, neutralise a much larger quantity of sulphuric 266 M. Brandes on Atropiwn. [ApRrn, acid. If, however, there was only a slight imaccuracy in the analysis, or if there had remained some free sulphuric acid in the salt, this of course must make a great difference in the result, the experiments being made with so small a quantity. I therefore, thought it necessary to repeat my analysis with a larger quantity of salt, for which purpose | dissolved a new quantity of atropium in diluted sulphuric acid, and exposed the solution to spontaneous evaporation. | obtained beautiful crys- tals, which | washed with alcohol, and repeatedly pressed them between fine blotting paper. Thus I obtained 18 grs. of sul- phate of atropium. . Five grains of this salt were carefully heated to expel the water. The loss amounted to 1+ gr. which indicates 25 per cent. water of crystallization. | Ten grains were dissolved in water, and decomposed by muriate of barytes.. The weight of the sulphate of barytes was 11 grs. equal to 36°13 per cent. of sulphuric acid. i! » After the deduction of 25 water and 36°13 sulphuric acid, there remains 38°87 for the atropium, and the composition of sulphate of atropium will be: Atropium . ...... Pn nce ose BOOT POD TAG AGE as a al nid wasens. sion Mamhcmen 36°13 \ of OS ae te epi Sata wk alee 25°00 ! | 100-00 _ The close approximation in the results of both analyses must evidently lead me to the conclusion that the error could not be very great. My doubt as tothe great saturating capacity of the atropium induced me, however, to make a third experiment. I took atropium, obtained by cooling a hot spirituous solution, put it into some fresh alcohol, and added sulphuric acid until it was dissolved. The spirituous solution was completely clear, and yielded, after spontaneous evaporation, beautiful crystals of sulphate of atropium. After washing them with ether until this fluid ceased to redden litmus papey, I dried the salt between fine blotting paper. | chit» . : With this salt -I repeated my analysis. By drying three grains I found the water of crystallization amounting to nearly 24 per cent. Three grains were dissolved in water, and the solution reddened litmus paper slightly, notwithstanding repeated wash- ing with ether. The sulphuric acid: was precipitated by a so- lution of muriate of barytes. The weight of the sulphate of Le after exposing it to a red heat, was 3°25 grs. indicating 1-113 gr. of sulphuric acid, equal to 37-1 per cent. | _ The composition of sulphate of atropium, according to this analysis, is, therefore, ! : ib 1821.] M. Brandes on Atropium. 267 Atropium....... dian. dupe ts aaa f PSS 5 Sulphuric acid. ....esecerceee sree eo PI Oe CA a he tn 5 to 058 eae wore 24° 100-0 This I thought sufficient to remove all doubts as to the great saturating power of atropium. It, proves the peculiar nature of this alkaline body, when compared with the rest of the seanalo- gous substances, all of which are capable of neutralising only a very small quantity of acid. Even picrotoxium, though accord- ing to Boullay, only crystallizable when an excess of acid is © present, as appears to be the case with atropium, is capable of combining with only nine per cent. of sulphuric acid. I have little doubt that the mean number of these three:analyses will approach very near to truth, and that, therefore, sulphate of atropium is composed of | PEIRO DUNT o'e ns stein ns gan MUA AA HOS . 38:93 POUND IUNAC, ACH a 3+ vo 016 me pase sient »» 30°52 gL NP uae a dia dpehet ects th po. 2459 3 100-00 It seems as if atropium is capable of combining in different proportions with sulphuric acid.. I once added an excess of sulphuric acid to atropium diffused in water, and I observed a sudden formation of long prismatic crystals, which: seemed to, be bisulphate of atropium. These crystals required several hun- dred times their weight of water for solution, while the salt of atropium which I analysed was soluble in four or five parts. It is well known that with picrotoxium the case is similar. I made several experiments to prepare that salt, but I could succeed only when I diffused atroprum in alcohol, and then added an abundant quantity of sulphuric acid. By this process the salt quickly appeared as a crystalline precipitate. Once as | evaporated a spirituous solution of sulphate of atropium, I was struck with the smell of bitter almonds. To determine whether the solution contained prussic acid, I diluted it, and added some solution of sulphate of deutoxide of iron; there did not, however, appear the least trace of a blue colour. Atropium and Murvatic Acid.—The: salt produced by the combination of muriatic acid and atropium appears in beautiful ~ white brilliant crystals, which are either cubes or square plates, similar to the muriate of daturium. It is readily soluble in water and alcohol. By nitrate of silver the chloride is precipi- tated, and the alkalies precipitate pure atropium from it. Even after the most careful washing, I always observed some traces of free acid. Analysis of the Muriate of Atropium:—I undertook this ana- 268 M. Brandes on Atropium. [Aprit, lysis not only to ascertain the composition of this salt, but also to ae additional evidence as to its great saturating power. (A.) Three grains of muriate of atropium, when dried at such a temperature that no decomposition of the alkali could take place, lost nearly 1;4,th gr. (B.) Three grains of the same salt were dissolved in water, and the atropium thrown down by ammonia. After repeated washing with small quantities of water, it was collected on a filter, which, after being dried carefully, showed an increase of weight of nearly 1.9,th gr. which were atropium. e composition of this salt is, therefore, Atropium rela Rigen Selieadigho a bapa 0 i aye 39°19 Muriatic acid...... e+ secs. 1 A RET IONE 25°40 gE NR beni! RE FE badartnes ate 35°41 100-00 _ Atropium and Phosphoric Acid.—Atropium, when dissolved in a great quantity of phosphoric acid, and evaporated, forms a mass like gum, which attracts the moisture of atmospheric air, and deliquesces. “If less phosphoric acid is used, the solution, after spontaneous evaporation, yields some quadrangular prisms, which salt is readily soluble in water, and is likewise readily dissolved by alcohol. On other Salts of Atropium.—Nitric, acetic, and oxalic acid dissolve atropium, and form acicular salts, all soluble in water and alcohol. The acetate and nitrate of atropium are hygrome- tric. All are decomposed by the alkalies and. by their carbo- nates. | | Nitric acid acts much less powerfully on atropium than on strychnium, according to Pelletier and Caventou. Observations on the Equivalents of Atropium.—I have shown that sulphate of atropium is composed of SEO so sapecs s (nme eteracna Fe 38°93 ROEIEOTIC RCM Nos vb.e > oso oie on os 94 36°52 WeOtEE, voces Se Loh eal een’ aha cabo 24°55 100-00 and that muriate of atropium consists of Atropium Pee: OW ili: Sis b a-ciuteetwwsbiice le 39°19 Muriatil®: S010. ctstiedpew bb 4 jeowetn OAD CE AR A OSS dievasans ‘eal wine 35°41 100-00 If we admit that in the alkalies from plants, the same laws exist as are ascertained with respect to those from inorganic bodies, we shall be better able to find their equivalent number, as I have shown in my-analysis of sulphate of morphium. The 1821.) _M. Brandes on Atropiun. : 269 sulphate of atropium appears to contain three times as much oxygen in the acid as in the base; and as 36:52. sulphuric — = 7:289 will indicate the acid contain 21°865 oxygen, oxygen in 38°93 of atropium. he muriates contain, according to Berzelius, in their acid, twice the oxygen which exists in the base, and 25:4 muriatic : Fe" ; F 14 acid containing, according to Berzelius, 14:825 oxygen — = 7:412 will indicate the oxygen in 39°19 of atropium. By comparing these two results, it will be found that they differ very little. Iam, however, inclined to suppose the result of the analysis of the sulphate of atropium to be the most cor- rect, and then 100 parts of atropium would contain 18-91 oxy- gen, a quantity far exceeding the oxygen found in any one of the similar alkalies. , | There are, however, strong reasons for believing that the different salts which have been analyzed are bisulphates and ' -bimuriates, and then the oxygen of the atropium would only amount to one half of the above-mentioned quantity. The salt which is above described as a bisulphate then would be a qua- drisulphate. The oxygen in 38-93 atropium would then be 3°644, and 100 parts of atropium would contain 9°4 of oxygen. The oxygen in the different parts of sulphate of atropium would be: _ Oxygen ALTODIUGE 64 5 5 8:09 510 PS. «ach, dieses 3°644 Sulphuric acid ...... Ts 21-865 WWELEY 6 ~cawe Sic 9 4:5'0.4.00 oo Oa 21°654 The oxygen in the acid and in the water, therefore, are equal, and six times that of the atropium. According to Berzelius’s theory, the oxygen in the muriate of atropium would be : Oxygen JA tropium .5536!6 oes BONG 5% 3°706 Muriatic acid. ...... OE PS 14-808 Water is 2088 Ui B64) Lee. 31-784 The quantity of oxygen in the acid is four times as much as that in the atropium, and that of the water twice as much as that of the acid. 3 : One hundred parts of dry sulphate of atropium contain PNP oe, rs Pan ehced 51°59 Sualpnaric acta sos ETP Pe ae ab 48°41 100-00 Or it consists of |): 270 M. Brandes on Atropium. [Aprit, Atropium .....4. vee 10000 26.56. 1065 Sulphuric acid ...... 93°83 .....4 100°0: One hundred parts of muriate of atropium would consist of Atroplum oss. eee 0 SUE £2. OR68 Muriatic acid. 00). ives SURE 2 SSD: . 100-00 And Atropium.... 100°0 .... 1545 would combine with Muriatic acid. 64:8 .... 100-0 On the Alteration which Atropium undergoes when heated with Potash, and when burned.—When I tried some other sub- stance obtained from the atropa belladonna by heating it with potash, i obtained a salt which, when supersaturated with acetic acid, produced with muriate of iron a red solution. I inferred from this, that there might be formed sulphochyazic acid. Sus- pecting this vegetable substance to contain atropium, I took some of this alkali as it had been precipitated from a decoction of atropa belladonna, and heated it with a solution of pure potash ima platina spoon. As soon as the action of the potash ee a distinct smell of ammonia was perceptible, and a glass rod with strong muriatic acid produced a white cloud when brought near to it. The residuum was dissolved in water, supersaturated with acetic acid, and tested with muriate of deutoxide of iron, which instantly produced a red colour. HY This experiment did not always succeed. It proves, however, that under certain circumstances there may be formed a sub- stance from atropium, which ee a red colour with deutox- ide of iron, and which probably is sulphochyazic acid. Sulphur is, perhaps, a constituent of atropium. The potash I made use of had a slight trace of sulphuric acid. I have been obliged to discontinue my experiments on the roperties of this alkali. The violent headaches, pains in the ae and giddiness, with frequent nausea, which the vapour of atropium occasioned while 1 was working on it, had such a bad effect on my weak health that I entirely. abstained from any further experiment. I once tasted a small quantity of sulphate of atropium, the taste was not bitter but merely saline, but there soon followed violent headache, shaking in the limbs, alternate sensations of heat and cold, oppression of the chest, and aad. in breath- ing, and diminished circulation of the blood... The violence of these symptoms ceased in half an hour.. : Even the vapour of the different salts of atropium produces giddiness. When exposed for a long time to the vapours of a solution of nitrate, phosphate, or sulphate of atropium, the pupil / 1821.] Mr. Smithson on some Capillary Metallic Tin. 271 of the eye is dilated. This happened frequently to me, and when I tasted the salt of atropium, it occurred to such a degree that it remained so for 12 hours, and the different degrees of light had no influence. This is sufficient to show the poisonous effect of atropium. | ArtTicLe VI. On some Capillary Metallic Tin. By James Smithson, Esq. FRS. (To the Editor of the Annals of Philosophy.) SIR, Paris, Feb. \7, 1821. M. Ampere, a few days ago, accidentally in conversation, mentioned a fact to me which much excited my attention, as it appeared to. me completely to confirm the explanation I had ventured to offer of the mode of formation of the capillary cop- per in the slag of the Hartz, printed in the Annals of Philosophy for July, 1820. | 3 For some purpose of the arts, Mr. Clement formed a cylinder of copper, and, to give it strength, introduced into it a hollow cylinder, or tube, of cast iron. To complete the union of these two cylinders some melted tin was run between them. With the exact particulars of this construction, I am not acquainted, but the material circumstance is, that during the cooling of this heated mass, a portion of the melted tin was forced by the alte- ration of volume of the cylinders: through the substance of the cast-iron cylinder, and issued over its internal surface in the state of fibres, which were curled and twisted in various direc- tions. This form in the fibres of copper I had considered as very favourable to my hypothesis. Such was the tenuity of these fibres of tin that little tufts of them applied to the flame of a candle took fire, and burned lke, cotton. This passage of. melted tin through cast-iron has a perfect agreement with the passage of water by pressure through gold, and tends to elucidate and confirm the account of the celebrated Florentine experiment. Had the water on that occasion issued solid, it would have been in fibres. This penetration of solid matters by fluids, by means of great mechanical force, will, perhaps, come tobe thought deserving of more attention than has been yet paid to it; besides any scientific results to which the consideration of it may lead, it _may be found to afford compound substances, not otherwise obtainable, and of value:to the arts. Lam, Sir, your most,obedient servant, : JAMES SMITHSON. ? ol = fs ' — \ ; Articite VIII. A Mathematical Inquiry into the Causes, Laws, and principal Phanomena of Heat, Gases, Gravitation, &c. By John He- rapath, Esq. DEAR SIR, Cranford, near Hounslow, March 21,1821. Tue following mathematical investigation of the causes, laws, and principal phenomena, of heat, gases, gravitation, &c. was drawn up about 10 months since, for the purpose of being laid before the public, in the Transactions of the Royal Society. A knowledge that the Royal Society had been desirous of having these subjects investigated, and a belief that they would, there- fore, have been pleased with this mark of my respect, and have caused the subject to be sifted to the bottom, were the motives which induced me to present them with the first fruits of my labours. Having, however, notwithstanding the marked kind- ness of the President, and another highly distinguished and enlightened member of that Society, experienced from others an unlooked-for, and, I might almost venture to say, an illiberal opposition for upwards of nine months, I have thought it expedient to withdraw this paper, together with another which I composed at the suggestion of Sir H. Davy, confirming by experiment m views on the more material points, in order to bring them bo before the public through a different channel. It is not my intention here to detail the discouraging and extraordinary line of conduct which has been pursued in this affair, because I shall have it in my power, at the end of these papers, to enter fully into particulars; but I request you will have the goodness to print the communications just as they now stand; for the circumstances of the case being such that it will be necessary publicly to invite the attention of the whole Royal Society to this subject, I wish to make no alterations, but to give those who have opposed me a fair opportunity of overturnin that against which they have not, in so long a period, produce one valid objection; or of justifying a conduct, which, though but belonging toa part, might, possibly, in the eyes of the world, from the importance of the subject, produce serious reflections on the whole of a Society, so long distinguished for its candour, liberality, and prompt encouragement, of scientific pursuits. I have the honour to be, dear Sir, Your most obedient servant, To Richard Phillips, Esq. JoHN HERAPATH. New Series, you. 1. 95.:)8 8974: ‘Mr.Herapathon the Cavises; Lawsjdnd principal [A pain, On the Physical Constitution wv the Universe. (In a Letter to Davies Gilbert, Esq.h MP. FRS. &c.) DEAR SIR, | : “*"In'the following: memoir, which’ I ‘have’ to request you will do me the honour of submitting to the consideration of,the Royal Society, I have endeavoured to unravel the causes of some of the leading phenomena of the universe, such as those of heat, . eh a &c. That a correct judgment may the more easily ‘he formed of the nature of this memoir, ‘I have prefixed a brief “account of the train of thought T pursued in my investigations, “which will tend to throw a considerable light over what follows. _ ‘And because I conceive no theory established, however well it “may accord with phenomena, unless it can be shown all others “do not, lintended to take a review of some of the principal hypo- “theses that have been advanced and supported by different phi- “losophers, and to show wherein I think them defective; but “afterwards considering that this would extend the memoir to-a “much greater length than T wish, and that I might probably be - obliged to press a little hard on the favourite opinions of some respectable ‘philosophers, I have for the present laid this design “aside. For similar reasons I have omitted all comment and ‘comparisons, except what are necessary for the elucidation of the “subject. I have likewise, in consequence of a conversation that FP lately had with W. Clayfield, Esq. materially changed the plan of this memoir, so as to render the connexion and dependence “between the principles and consequences more apparent. And “in order to trespass as little as possible on the time of the Royal “Society, I have only demonstrated some of the elementary pro- ' positions ; reserving the proofs of others to a future period, when, af the little that’ I have done recetve the countenance of the ‘Royal Society, 1 might be induced to take a more elevated view ‘of the subject, and to touch upon other things that are not men- ~ tioned. ” | The Royal Society will easily perceive that I am indebted for the hint of the cause of gravitation tc Sir Isaac Newton, though, pethaps, it will be found, that IT have carried the idea much fur- ‘ther, and have extended it to the development of a much greater “variety of phenomena than he could have anticipated. It would ‘bé preposterous for mein this place to name other distinguished ‘vaamigy age to whose accurate experiments and luminous views have, in the course of my inquiries, ‘been under great obliga- tions ; but I cannot let slip this opportunity of acknowledging, that ifit shall appear I have been any way successful im my soli- tary rambles through these exalted regions, it is probably in a great measure owing to your kind encouragement and directions, and to the flattering approbation you were pleased to bestow on my juvenile efforts so long ago as the beginning of 1809, when I had the pleasure of being introduced to you:by my late respected 1821.]. Phenomena of Heat, Gases, Gravitation, &c. 275 friend W. Perry, Esq. of Winterbourne. Without such stimuli, I might never have had sufficient confidence in myself to tread those intricate and almost trackless paths of science. An Analytical Inquiry into the Cause of Gravitation, Heat, &c. Several years ago, namely, in July 1811, while amusing myself with calculating some of the lunar equations from theory, I was induced.to try to compute the annual equation to the moon’s mean motion, somewhat after the manner in which Newton has calculated the magnitude of the variation. The result of: this calculation, which considerably exceeded the quantity given in the tables of Halley, the only ones I then had, very much sur- prised me. At first 1 thought I had committed some error, or made some erroneous assumption; but on re-examining the calculus, and making every allowance which I thought. might have any influence, | satisfied myself, that as far as my funda- mental principles were correct, nothing was neglected which could affect the result to any thing like the magnitude of the difference. At another time it occurred to me, that the quantity of the equation, as given in the tables, might possibly be itself too small. 1, therefore, set myself about correcting it from the observations at the end of Halley’s tables; but so far from solv- ing the difficulty by this means, I found the difference much greater; for, as far as | remember, the maximum of the equation 1 found'to be, instead of 11’ 49’, only about 11’ 17”; that. is, but a few seconds greater than the quantity given in the very correct tables of Burg. Baffled, therefore, in this attempt to reconcile observation and theory, I conceived that the quantity determined from observation must be the result of two opposite equations, one of which had escaped the cognizance of theory. And in this opinion I seemed to be more confirmed by another calculation of this equation, by means of an exponential theorem I had just before discovered, and by observing that the computa- tion of the same equation by Machin, on the principle of an. -equant, came out also much greater than the quantity by obser- vation. Itis true I was for a little while staggered in my opinion by the statement of Newton, in the scholium to prop. 35, book 3, of the Principia, in which he says, that he had. calculated the mean greatest quantity of this equation from the theory of gravi- tation at 1149’. But as I observed that he simply named the result without even hinting at the method of calculation, though just beneath, in the same scholium, he minutely enough describes his calculus of one or two other equations of considerably less difficulty ; and as I had observed that the quantity I had brought out would coincide with his, if diminished in the ratio of the moon’s synodical to her siderial period, I thought it very pro- bable that. Newton had pursued the same course that I had; and “that finding his numbers would agree with observation, if dimi- “nished in the said ratio of the synodical to the siderial period, Bap ree 3 } 276 Mr. Herapath on the Causes, Laws, and principal [Arrin, he diminished them, thinking there might be a reason for it which he did not perceive ; but not being thoroughly convinced, he chose rather to omit than describe a calculation, with every part of which he was not porfecty satisfied. This at least to me a very plausible way of accounting for Newton’s silence ; but whether it be a correct one, it is, perhaps, not worth the trouble of discussing, especially since the complete calculation of this equation, by the celebrated Laplace, in the Mécanique Céleste, shows, that whatever may have been New- ton’s method, it was, as well as my own, much too loose and inaccurate to be depended on. It is, however, remarkable, that all, or most, of the calculations of the ann. equa. hitherto made from theory, give the quantity of this equation greater than | observation ; and this is even the case with Laplace’s. Having now, as I thought, satisfactorily accounted for the slifference between Newton’s numbers and mine, | became more strongly persuaded in myself that the tabular magnitude of the nn. equa. was the difference of two equations; and, therefore, I frequently tried to unravel the cause and magnitude of the indeterminate one, but without success. At length, about the middle of the following September (1811), my attention being involuntarily turned to a consideration of Newton’s opinion respecting the cause of gravitation, I fancied that I saw a true solution of the difficulty in question, as well as a complete deve- lopment of the cause of gravitation. If, argued I with myself, gravitation depends upon the action of an elastic medium, such as Newton supposes, which grows rarer and rarer as you approach the dense bodies of the sun and planets, there ought to be some reason for this variation of density; and as Newton has ‘not, as far as I could perceive, given any, I began to consider what it might * be. And after some little thinking, it occurred to me, that if this medium be of the same nature as our atmo- sphere and other gaseous bodies ; that is, if it be capable of being expanded by heat, and contracted by cold, then, the sun ‘being a very hot body, and the heat being so much the greater the nearer we are to him, the density of the medium ought, therefore, to decrease with a decreasing, and increase with an increasing distance, the same as Newton would have it. And ‘because we find by experience that dense solid bodies receive heat more strongly than much rarer ones, particularly. than gases, the dense bodies of the planets being heated by the solar Tays as well as by the medium about them, ought, it appeared to me, to be hotter than this medium, and consequently ought to roduce the same effects on the medium as the sun, though not am so great a degree. Therefore if, as Newton imagines, the * The only accounts I had seen of Newton’s ideas of this subject were in his Optics, end at the end of the Principia. I have, however, lately read a letter that he wrote te Mr. Boyle, printed in Bishop Horsley’s edition of his works, wherein he gives his opi- nion of this fluid medium as being of the same nature as our air. 1821.] Phenomena of Heat, Gases, Gravitation, &c. 277 particles of the planets be impelled towards the sun by the ine- quality of pressure on their further and nearer sides, the denser parts of the medium pressing more forcibly than the rarer, the same reason will likewise Hold good why bodies should be impelled towards the planets and other material parts of the system. _ And by considering these things further, it seemed to me that if such be the cause of gravitation, the intensity of the impelling force should be subject to the influence of two circumstances ; namely, the number of particles in the central body, and their temperature ; so that it becomes greater when either of these _ becomes greater, and less when it becomes less. But since the earth in its passage round the sun is sometimes at a greater and sometimes at a less distance from it; and since the regions which are nearer the sun are hotter than those which are more remote, the temperature, and consequently the attraction of the earth, should increase as the earth approached the sun, and diminish as it receded from it, so as to be greatest about the perihelion, and least about the aphelion. And this being the case, the moon must move in a contracted orbit, and swifter round the perihelion earth, and in a dilated orbit, and slower round the aphelion earth ; by which means an- equation to the moon’s mean motion must be generated contrary to the ann. equa. and diminish it, the same as [ had supposed some unknown equation ought to do with the theoretical annual equation to reduce it to the tabular. Thus it happened that the inadequate method of computation [had adopted, brought out a quantity which so well accorded with my first theoretical views of the cause of gravitation, that L could not help placing great confidence in the theory I had embraced. I, therefore, carried on my speculations with that ardour which a strong prejudice in favour of the truth of my principles, and the sanguine hopes of succeeding in so great @ problem as that of developing the cause of gravitation, might. naturally be supposed to inspire; but 1 soon found that before I could proceed any further, I must establish the cause of heat, and reduce its phenomena to mathematical laws. This [| at first attempted to do by endeavouring to find out the relation which should exist between the masses of the particles of the ethereal medium and their repulsive force, in an equation connected with. their distances from the sun. But being disappointed in this, and a great number of other attempts that | made, I became much dispirited, and was often on the point of forming a reso- lution never to consider the subject again. Indeed I frequently wished to persuade myself that the discovery was altogether beyond the reach of human ability ; and with this view tried to thrust it entirely from my mind. Yet sometimes, when my thoughts were involuntarily turned this way, the idea that two 278 Mr. Herapath on the Causes, Laws, and principal [Arrin, inanimate bodies could act on each other ata distance without’ some other means than that of a mere tendency, or inclination, in them to approach, would appear so strongly unphilosophical, and the apparent coincidence of several phenomena, with con- clusions | had drawn from my notions of gravitation, so very seducive, that I could not avoid thinking the views I had taken were tolerably correct ; and that there was only wanting the direction of some happy idea, which patient perseverance might. poss attain, to set the whole in a clear and irrefragable light. us between hope and despair, between unceasing attempts. and mortifying failures, I continued until May 1814, at which time my ideas of heat underwent a complete revolution. Previous: to this time I had conceived heat to be the effect of an elastic fluid; and on this supposition had repeatedly attempted to reduce its laws to mathematical calculation; but uniform disap- pointment at length induced me to give this hypothesis a careful investigation, by comparing it with general and particular pheno- mena. The result of this investigation convinced me that heat could not be the consequence of an elastic fluid. At the time I was making this comparison, I took every opportunity of exa- mining how far the other ncseoens (which until now I had forgot was sanctioned by the names of Newton and Davy) agreed with phenomena, and was so well pleased with its sim- plicity, and the easy, natural manner in which the different: phenomena seemed to flow from it, that I regretted havin neglected it so long, and determined to consider it more atten- tively. A difficulty, however, soon appeared in the application of this theory of heat to gaseous bodies, which I had some trouble to conquer; for as | still adhered to the hypothesis of gases being composed of particles endued with the power of mutually repelling one another, I could by no means imagine how any intestine motion could augmeut or diminish this power. Here then I was involved in another dilemma; but after | had revolved the subject a few times in my mind, it struck me that» if gases, instead of having their particles endued with repulsive forces, subject to so curious a limitation as Newton proposed, were made up of particles, or atoms, mutually impinging on one another, and the sides of the vessel containing them, such a constitution of aeriform bodies would not only be more simple than repulsive powers, but, as far as I could perceive, would be consistent with phenomena in other respects, and would admit of an easy application of the theory of heat by intestine motion. Such bodies I easily saw possessed several of the properties of gases ; for instance, they would expand, and, if the particles be vastly small, contract almost indefinitely; their elastic force. would increase by an increase of motion or temperature, and’ diminish by a diminution; they would conceive heat rapidly, and conduct it slowly; would generate heat by sudden com- 1821.) Phenomena of Heat; Gases, Gravitations de: (276 ression, and destroy it by sudden rarefaction.; and any. twoy,, srr ever, so small. a. communication,, would quickly and.+ equally intermix. 7 ) ' Besides these, other properties equally consistent and gratify- ing, presented themselves; but as,these were merely loose views of the subject, I soon resolved.to examine it more.rigorously, and. to try if 1 could not bring it. to. the, test of mathematical laws. In this, however, I met with a difficulty considerably superior to... any I had: yet encountered in the, course. of my analysis, and. which, before 1 overcame it, gave me more real. uneasiness than,. perhaps, it) can be imagined. it should.. But the truth is,. my,. views. of the subject expanded.so much as I proceeded that even. in this early stage I, fancied 1, perceived, in. the solution of the, problem | was about, not only the discovery of the cause of gra- vitation, but also. of, the causes of all the, other phenomena of: nature; aud my thoughts were, therefore, turned upon it with... am intenseness and anxiety which I never before experienced,.,, and which can scarcely be appreciated except by those who have. been placed in a similar situation. To meet. now, therefore,... when I thought I had almost completed the discovery, with an. obstacle which it baffled. my, utmost’ efforts to)surmount,, and. which threatened, destruction to the fabric I had.so laboriously, endeavoured to raise, was a shock I. had. hardly philosophy enough to withstand. However, as I had proceeded so far, and. . had been so. much led away by the seducing comcidence of the consequences of my theory with phenomena, I determined to examine it thoroughly, and, if I should find it. erroneous, to pub- lish it together with the illustration of its errors, that.if it could. do no other good, it might serve for a beacon to prevent others. from running against the rock on which my hopes.and expecta- tious had been wrecked. | The obstacle to which Laliude is this: I,saw directly I began: to-consider circumstances attentively, that.if the constitution of, things be such as | supposed, the ultimate atoms of all bodies,, and, therefore, the particles of these gases, .which I looked upon tovbe no more than these ultimate atoms, must be absolutely. hard; they must admit of no breaking, splitting, shattering,. or: any impression whatever; and yet if the gases are to maintain their elastic property, and this property be the result of the par- ticles mutually impinging on one another and. the sides of the’ containing vessel, the particles, or atoms, must likewise be elastic ; that is, they must be’ soft’; for elasticity, according to the ideas we have /of.it, is nothing but active softness. There- fore, it appeared to.me that the ultimate atoms/ought to possess two properties,in) direct. contrariety,. hardness. and. softness, which is manifestly impossible. . Having arrived. at this conclusion, which appeared to render. the probability, of success. of all. future inquiries. in this track: desperate, it might be supposed that my efforts:.would: have ter-: . 280 Mr. Herapathon the Causes, Laws, and principal [Arruit, minated. Nor, perhaps, is there any thing that could have induced me to ie psa myself any more with this subject ; but the resolution I had formed to examine it thoroughly, and a fond- ness for the plausibility of my preconceived notions that I could not shake off, and which would oftentimes, even against m inclination, prompt me to try to explain away the abeurdit had brought out. The first thing that suggested itself for this purpose was, that elasticity might spring from a different source to what was commonly believed, and might be the property of hardness ; for I observed that the harder the bodies are, gene- rally speaking, the more elastic they are. Thus glass is ve hard, and likewise very elastic; and the same is true of steel, and most of the other metals. Upon this hypothesis, therefore, I now tried to investigate the laws of gaseous bodies; and as far as I then carried my speculations, the conclusions I drew exactly coincided with phenomena. But reflecting more deeply on the subject, I convinced myself that, however well these inferences and phenomena might agree, elasticity could not bea property of hardness ; and, therefore, that the hypothesis I had assumed could not be correct. At length, after a great deal of intense and fruitless thought, I remembered that when, some bi before, reading the vulgar doctrine of the collision of hard odies, I was very far from being satisfied with it ; but looking upon it then as an abstract and almost useless subject, I could not summon resolution enough to give it a critical investigation. Being now, however, drawn to the point by my analytical inquiries, the recollection of this dissatisfaction excited me to consider the circumstances connected with it attentively. The result of this consideration was a theory for the collision of hard bodies, so very different from the received theory, that it was not until I had examined it in a variety of shapes, had brought it to the test of experiment by my mathematical investigation of the laws of gaseous bodies, and had found that a theory something like it had been wey | given by Wren and Huy- gens, that I could satisfy myself | had not committed some oversight. But having considered and reconsidered it many different ways, without discovering any thing that could militate against it, 1 proceeded to carry on my theory as far as I judged it would be wanted, and then assumed the following postulata as the basis of my future inquiries. . Postulata. 1. Let it be granted that matter is composed of inert, massy, » perfectly hard, indestructible atoms, incapable of receiving any change or impression in their original figure and nature. 2. Let it be granted that all solid and fluid bodies have their smaller parts composed of these atoms, which may be of different sizes and figures, and variously associated, according to the manner which the constitution and nature of the bodies require. 1821.] Phanomena of Heat, Gases, Gravitation, §c. 281 3. Let it be granted that gaseous or aeriform bodies consist of atoms, or particles, moving about, and among one another, with perfect freedom. 4. Let it be granted that what we call heat arises from an intestine motion of the atoms, or particles, and is proportional to their individual momentum. ‘zh 5. Let it be granted that a gaseous- body of very great tenuity in its parts fills all space, and extends tv its utmost limits. I have purposely put these hypotheses (if indeed we can call those things hypotheses which have been deduced from the analysis of phenomena) into the form of postulata, to avoid being obliged to establish them by direct demonstration. It is not my intention, for the reasons | have already given in the beginning of this memoir, to make any comparative remarks on their relative simplicity and probability. I shall only say a few words for the purpose of explaining the difference between my views on certain points and those which have been taken by others. One of the sublimest ideas of the ancients was, that there is but one kind of matter, from the different sizes, figures, and arrangements of whose primitive particles, arises all that beau- tiful variety of colour, hardness and softness, solidity and fluidity, opacity and transparency, &c. which is observed in the productions of nature. Our first two postuiata do not necessa- rily require that there should be but one kind ‘of matter; there may be several kinds. But since it seems possible to account for all the phenomena on the supposition of one kind only, and since nature is always disposed to employ the simplest machi- nery, probability is strongly in favour of the ancient.idea. In fact it does not seem to be impossible, from some of the pheno- mena of light and other circumstances, to show that nature has embraced the simplest means, and has likewise, if not in the size, at least in the figure of the atoms, confined herself within certain limits. But these things are too recondite to be pursued in this memoir; and experiments have not yet furnished us with sufficient data to be able to exhibit the exact line and rule with which nature has laid out her work. | Philosophers, since the time of Newton, have taught us that the elasticity of gases is owing to a mutual repulsion between their particles, by which they endeavour to fly from one ano- ther ; but by our third postulatum we have divested matter of this repulsive property, and nevertheless, as it will be seen, the laws of gaseous bodies, investigated under this point of view, agree mathematically with phenomena. | The advocates for the theory of heat by intestine motion have usually considered the temperature as measured by the velocity of vibration; and I am not aware that any of them have defined it otherwise. This will do very well for different temperatures of the same body; but it seems to require the theory I have given in the fourth postulatum to enable us, under all circumstances, to compare the temperatures of different bodies. 3 ! 282 Mr. Herapath on the Causes, Laws, and principal’ [Ar riu,: In the fifth postulatum I have given the fluid of Newton for explaining the cause of gravitation. This illustrious philosopher: has so clearly developed his ideas of the nature and. action: of! this etherial fluid, that I have had scarcely any thing'to do but to confirm them with the application of the principles: of ours third and fourth postulata. It is true that the novelty of the» views I have been obliged to take, andthe unbeatenness of the track, have rendered even this a task of some difficulty; but: the results I have obtained will, I presume, convince the Royal Society that my efforts have not been wholly unsuccessful ; and. that this idea of Newton, which has, from the uniforny want of success to demonstrate it, often been placed to the account of this great man’s foibles, was not adopted upon light grounds; or: without mature consideration. | Or THE COLLISION OF PERFECTLY HARD BopieEs. Definitions of Hardness, Softness, and Elasticity. Def. 1.—That body is perfectly hard whose figure cannot be altered by any weight, or percussion. : | Corollary Hence a perfectly hard body must also be per- fectly entire ; for if it be composed of parts, there may be a force sufficient to separate them, and then the figure would be changed, which is against the definition. By a hard body, I mean one without parts, unchangeable, and indivisible, such as, perhaps, the primary particles of matter are. Def. 2.—The figure of a soft body yields to pressure, or per- cussion, without recovering itself again. _ Cor.—Hence a soft body cannot be entire, but must be com- posed of parts, which, being displaced, retain whatever situation 1s given them. ef. 3.—A perfectly elastic body, like a soft one, suffers: its figure to be changed by force, but recovers it again with an energy equal to the force by which it was changed. ‘or. 1.—Therefore an elastic body does likewise consist of particles, which, like the particles of a soft body, may be deranged ; but as soon as the power is overcome by which they. » were disturbed, they exert as much force in recovering their situation, as was used in depriving them of it. Cor. 2.—Because an elastic body recovers its figure with the same force by which it was changed, as much motion is gene- rated in the recovery as was destroyed in the loss of the figure. Prop. I. If two bodies absolutely hard impinge’ on one another, the duration, or smartness, of the» stroke,.is: indeperdent: of. the velocity: of the contact ; that is, itis neither augmented mor: dinainialinalitie any increase or diminution of the relative:velocity: of the bodies. : 1821.] Phenomena of Heat, Gases, Gravitation, &c. 283°. For the bodies being absolutely hard, their figures do not. yield to any stroke, however great it may be, and, therefore, the» shock is no sooner given at one part than it is equally felt at: every other; that is, supposing the stroke is given in the direc=) tion of the centre of gravity. ‘Therefore, the stroke can have no: duration, and consequently no increase or diminution of velocity can produce a difference. The same thing might also be proved thus : Let two unequal: hard balls, moving with equal momenta in opposite directions, be conceived to come ih contact at the same time with the oppo- site parts of another hard ball at rest, then will the intermediate: ball remain at rest, and not titubate the one way or the other,. nor be any more affected than if it had not been struck at all; for since the contacts are made at the same time, if the- inter- mediate hall titubates, that hall towards which it moves must: take a longer time to give its stroke than the other, and cannot have completed it until the titubation is destroyed, because, as: soon as the strckes are finished, the intermediate body evidently becomes quiescent in consequence of the assumed equality of the momenta ; but the balls being absolutely hard, their figures do not yield to the stroke, and, therefore, this exterior body itself, towards which the intermediate one titubates, before 1: has finished its stroke, must, on the supposition of titubation in the middle ball, have moved backwards; that is, before it has: finished the stroke, it must have had all its momentum destroyed, and a new contrary one generated. But the whole stroke which the ball could give consisted in its momentum ; consequently the: body must have given its entire impulse before it has completed. it, which is absurd. Therefore the intermediate body does not’ titubate, and the strokes are made equaily smart or in equal por-. tions of time, or rather both strokes are made in portions of time which have no duration. By deducing the collision of hard from that of soft bodies, we likewise arrive at the same conclusion. At the moment two soft bodies come in contact, the anterior parts of the second body communicate motion to the posterior parts of the first body, and a slight check is given to the second. The parts of the bodies: yielding to the blow, the bodies themselves approach nearer. In the second instant another acceleration and retardation take place, and the bodies approach still nearer. The same things: ensue in the third and succeeding instants, until at length the second body has itself lost and communicated to the first body.a . Sufficient degree of motion to enable it: to move with the same velocity which the second body has then left; after-which the stroke ceases, the two bodies are at’ their least distance, and go° on together, Thus it is with the collision of soft bodies, and those whose figures are yielding, except, perhaps, that the: strokes are given in-continued unceasing pressure, and not ina succession of impulses at statedintervals; but in whichever ways it’ be conceived‘to be-done, it’ amounts to the same thing, and? 284 Mr. Herapath on the Causes, Laws, and principal [Ar RIL, time is always consumed. If now, other things being alike, we suppose the bodies to increase in hardness, then, since their parts have a less disposition to yield to the force of percussion, | the intensity of the impulses (if we suppose the stroke to be given in impulses) will be stronger, the quantity of motion com- municated by each greater, and the time of the whole stroke, therefore, shorter. And if we suppose, ceteris paribus, the hard- ness to increase still more, the duration of the stroke will be still less, until, if the hardness be perfect, there will be no yields ing of figure, and no duration for the strokes. And since this is the case with every stroke between perfectly hard bodies, it follows that all the strokes between bodies absolutely hard have no duration, and are thence equally smart. Cor.—Hence we gather, that in perfectly hard bodies, the intensity of the impulse depends on the violence or momentum, of contact, and is independent of the velocity of contact, except. inasmuch as it is augmented or diminished by that velocity. Prop. II. If a hard spherical body impinge perpendicularly on a hard fixed plane, the body will, after the stroke, remain at rest on the plane. | For the plane having no motion of its own, and being fixed, the force with which the bodies come in contact will be equal to the momentum of the ball; and because action and reaction are equal and contrary, this momentum is the force with which the ball acts upon the plane, and the plane reacts upon the ball at the instant of contact. The force, therefore, with which the ball is acted on by the plane at the time of the contact in a direction opposite to its motion is just equal to its momentum ; consequently the momentum and action of the plane being equal and opposite destroy one another; and the ball having no other tendency continues at rest on the plane. Cor. 1.—Hence a hard ball impinging obliquely upon a fixed hard smooth plane slides along the surface of it in a vn direction with a determinate velocity. For if the motion of the body previous to the contact be resolved into two, one perpendi- cular and.the other parallel to the plane, the perpendicular part will be entirely destroyed by the contact, but the other part being that with which the body would neither recede from, nor approach the plane, will continue the same after as before the stroke, and will induce the body to slide along the surface of the plane in its direction, and with its entire force. Cor. 2.—From this proposition it appease that if, instead of the plane, the body meets with another equal and hard body moving equally in an opposite direction, the intensity of the stroke willbe twice as great as between the body and the plane ; for the plane being fixed contributes nothing»to the violence of the blow, but the other body coming with an equal force in a contrary direction, adds its whole motion to the force with which 1821.] Phenomena of Heat, Gases, Gravitation, &c. 285 - the other body would have come in contact with the plane, and, therefore, makes the stroke twice as great. This might probably be made more obvious thus : Suppose a hard plane, or other body, be held against a fixed hard body, and in this way receive the impulse of the ball; then, because that part of the intermediate body which is against the fixture is not urged any way by that fixture, the force with which the ball comes in contact with the other side is the force with which the sides of this intermediate body are driven together; but this force is the monumentum of the ball; therefore, that momentum is the force of constipation in this case. But if we now fix the intermediate body, and instead of the fixed body on one side of it imagine another equal ball to come in contact with it at the same time as the former, and with an equal momentum, then the force with which each surface of this intermediate body is urged towards its centre is equal to the momentum of each of the balls; and, therefore, the force with which the two surfaces are urged together is equal to the sum of these momenta, or to twice one of them; but this force is manifestly the force with which the two balls would have come in contact if there had been no inter- mediate body; therefore, that force is the double of the force with which either body would have struck a fixed plane. Cor. 3.—Hence if two hard and equal balls come in contact with equal and opposite momenta, they will separate after the stroke with the same velocity with which they met. For since the intensity of the stroke is the force with which each of the balls is ‘acted on in a direction opposite to that in which it came at the time of the contact; and since that intensity is by the preceding cor. equal to twice the momentum of either ball, each ball.at the time of the contact might be conceived to be acted on by two opposite forces, one its momentum, impelling it towards the other ball ; and the other, the force of the contact equal to twice its momentum impelling it in an opposite direction. The difference between these two forces, therefore, or the value of one momentum, is the force with which each ball retraces its path; and, consequently, the velocity of the separation of the balls is equal to the velocity of their approach. ‘This coincides with the theories of Wren and Huygens. Scholium. By the old theory of collision, two hard bodies coming in con- tact with equal opposite momenta will not separate after the collision, but will continue together; and the reason assigned for this is, that being unelastic, they cannot, when they meet, exert themselves to separate, and, therefore, must remain together. Such a method as this is not reasoning from the property of hardness, the physical force of the impulse, and the effect which that force would have upon the motions of the bodies ; but from the absence ofa property which does not belong to this class of 286 Mr..Herapath on the Causes, Laws, and principal [Avrit, bodies, but to one whose nature is so very different, as to be almost the very opposite. Hardness and softness.are diametri- cally opposite properties, and elasticity is nothing but an active kind of softness ; for elasticity consists in a vigorous restoration of an altered figure; and no body can have its figure altered »which is not more or less soft. To argue, therefore, that two hard ‘bodies which meet each other with equal and contrary momenta «cannot separate after collision, because they have no elasticity, sis evidently to abandon the definition of hardness, and)to adopt that of elasticity, which has no connexion whatever with it, ,and sconsequently ought, in such a case, to be excluded. It is no ‘matter of surprise, therefore, with such incongruous ideas, that mathematicians have hitherto had erroneous views of the theory eof collision of hard bodies. Probably the apparent sterility, if motinutility of the subject, has occasioned an apathy towards a scrupulous investigation, which the slightest idea of its import- ‘ance would have easily removed. Had it been imagined that the collision of hard bodies was connected: with the develop- ‘ment of the cause of heat, gravitation, light, magnetism, electri- -city,&c. itwould have been scrutinized with a care which nothing «could have escaped; and with a rigorous investigation, 1 am persuaded our ideas of the subject would have been very differ- ‘ent to what they are. | If there be any method of classification which should havea preference, it appears to me it should be to rank all those bodies sander one head which have mutable, and those under another — ewhich have immutable figures. To the latter class will belong shard bodies, ‘and to the former every variety of soft and elastic ‘bodies ; the one will give their strokes instantaneously, and, with- ‘out the lapse of time; the other, gradually and with time. In seach particular case, the physical nature of the impulse should ‘be considered, and a theory of collision framed accordingly. With such views, our theories of collision would be made to rest ‘on their true and. veritable principles, the physical nature of the bodies and of the strokes which they give. ay Many simple experiments might easily be devised to. prove ‘the truth of our second cor. ; for it is immaterial on what bodies we experiment: we can draw the same inference for/any. |The thing, however, is so obvious that I have generally considered it in the light of an axiom ; and have often ascertained the opinion of other people on the same subject by the following question : “Suppose a hard sphere, moving freely with a given velocity, ustrike directly upon a hard. fixed body, it would strike with a scertain intensity: but now suppose that instead of ‘the fixed body the moving sphere strike upon another hard equal body, ‘moving with an equal velocity, in an opposite direction, ‘what would be the relative intensities of these two strokes?” The answer has invariably been, that the latter would be the double of the former. This, it must be allowed, is not a mathematical, 1821.] \Phenomena of Heat, Gases, Gravitation, &c. 287 ‘or even a philosophical way of establishing the question ; but in a case of this kind, where I thought my prejudices » might influence my judgment, it appeared no bad method of examining ‘the soundness of my opinion by the standard of other people’s: From all these circumstances, it appears that the vulgar doe- trine of the collision of hard bodies is, in this particular case, incorrect, by making the intensity of the stroke only the half of what it should be. For'the bodies remaining together after the impulse, the force of the stroke upon each must be equivalent to ‘the motion destroyed; that is, to the momentum of either of ‘them. But the force upon each is the force with which they come in contact; the force, therefore, with which they come in contact is equal to the momentum of one of the balls; thatiis, agreeable to both theories, to the force with which either ball alone would, with the same‘momentum, strike a fixed plane. Prop. II. If a hard ball strike another hard ball at rest in the line of their centres of gravity, an exchange of state will take place; the former will remain at rest after the stroke, and the ‘latter will proceed in the same direction in which the first was moving, and with the same momentum. If this be not the case, the first body must, after the impact, either move backwards or forwards in the direction of the other body, with an equal or less velocity. But it cannot move back- wards, because the intensity of the stroke itself on a quiescent body can evidently never exceed the momentum ; therefore, if it ‘move at all after the stroke, it must follow the other body, with an equal or less velocity than this body acquires from the impulse. Suppose it be with a velocity 6, either equal to, or less than, that acquired by the other body; and suppose A represent the first body, and a its velocity before the impact. Then because (a — 6), A is the motion lost by A, on account of the impact, and consequently the motion gained by B, the other body. This quantity represents the intensity of the impulse. And in any other case (a” — 6’) A’ represents also the intensity of the impulse ; but if the quiescent bodies be equal, and if the momenta A a, A’ a’, of A and A’, before the impact be equal, the strokes themselves, by cor. to prop. | will likewise be equal ; thatis, aA —b6A =a’ A’— 0’ A’, and, consequently, b A = &’ A’; or the motion which is left to each of the bodies, A, A’, after the impulses, will bethe same. . Now whatever be the value ofthe momentum A a, if we imagine the body A to be vastly less than B, the velocity of B after the impulse must be vastly less than that of A before the impulse; and, therefore, the motion 6A, which remains to A after the impulse must be vastly less than A a, the motion of A:before the impulse. And if we suppose A so small as to have a ratio to B less than any assignable ratio, the ratio of A.6; and, therefore, of A’ b’to Ava, or A’ a’, will also be less than any assignable ratio. Therefore, 288 Mr. Herapath onthe Causes, Laws, and principal [Aprit, if the ratio of A’ to B be assignable, the motion of A’ after the stroke will be unassignably small ; that is, the body A will remain at rest. And because 0’ A’ is indefinitely small compared to a’ A’, the intensity a’ A’ — b’ A’ of the impulse will likewise be equal to the momentum a’ A’ of the moving body before the stroke. But since the intensity of the impulse is the force act- ing upon the quiescent body at the time of the impulse, it is also equal to the motion acquired by this body. Therefore, if a hard ball strike another hard ball at rest, &c. Cor. 1.—From this proposition it is easy to determine the motion and direction of a hard body striking obliquely with a given momentum in a given direction on another hard body at rest. For if A B be the direction 4 _E and momentum of the body previous to the stroke, and B C the direction in which it strikes ~ the quiescent body B, produce C B to E, on | which demit the perpendicular A E, and draw B D equal and parallel to A E, and B D will be the motion and direction of A after the stroke, and B C, if equal to E B, those of B. Cor. 2.—Hence it follows, that in any oblique collision on a quiescent body, the motions of the bodies after the impact will be perpendicular to each other. Scholium. I forbear to enter further into the collateral minutiz of this theorem, because it wouldlead me too far out of my way,and I am in haste to arrive at things of more importance. However, it is necessary to state that 1 have chosen this indirect method of demonstrating this proposition, for the sake of making it rest on principles as different and as independent as possible of those of a future proposition, from which it will flow as a corollary. ett ms k'¢ If a hard body overtake and strike another hard body, moy- ing with a less velocity in the same right line, the first body will, after the stroke, continue its course with the same velocity which the other body had before it; and the second body will acquire from the stroke a momentum equal to the difference of the velocities of the bodies previous to the contact, _ drawn into the mass of the first body; that is, if A, B, represent the two bodies, and a, b, their velocities before collision, the motion of A afterwards will be Ab, and that of B, Bb + (a — b) A. Because the bodies are both moving the same way, it is evi- dent that we may conceive the second body to be at rest, and the other body to strike it with a velocity equal to the difference of the velocities a and 6; in which case the proposition will come to the same thing as the last. Therefore (a@ — 6) A is the momentum, or force, of collision; and is, consequently, the 1821.] . Phenomena of Heat, Gases, Gravitation, &c... . 289. motion acquired by B and the motion lost by A. Whence the. motion of A after the stroke is Aa — (a — 6)A = 6 A, and that of BisB Ob + Aa— Ad. Cor. 1.—By this proposition, the direction in which a body - overtakes and strikes another being given, as well as the motions and directions of the bodies before the stroke, the motions and directions of the bodies after the stroke may” be found. Let A B be the motion and direc- tion of the body A before the impact, and let B C be the same of B, and let EB be the di- rection in which the impulse is made by A, and D B the intensity of it, or the quantity of motion with which A in the line E B overtakes and strikes the body B. Then join A D and DC, and they shall be. respectively as the > quantities of motions and directions of the bodies A and B after the stroke. pstae rd A Cor.2.—Draw AC; then, since A C is the motion com- pounded of the motions A D and DC, and likewise of A.B and BC, it follows that the aggregate motions of the bodies before and after the stroke, reduced to the same direction, are the same: and, consequently, the motion of the common centre of gravity of the bodies remains unaffected by the impulse. Prope. V. If two perfectly hard bodies, moving in the same right line but towards opposite parts, come in contact, an exchange of motion will take place ; or each body will retrace its path with the motion which the other had before the contact. f Let A and B be the two bodies, moving in opposite directions with the velocities a and 6. Then, because A a is the motion with which A advances towards the parts B is leaving, and BO ig the motion with which B advances towards the parts A is leaving, the sum Aa + BO of these momenta is the motion with which the two bodies approach ; and, therefore, the motion, or force, with which their surfaces come in contact. But the force with which the surfaces come in contact is the force with which each surface, or body, is acted on at the time of contact in a direction opposite to that in which the body was moving. Therefore, at the time of contact, each body is acted on by two opposite forces ; one its momentum ; and the other, the force of contact, or the sum of the momenta ofthe two. Consequently, the difference between these forces, or the momentum of the other body, is the motion with which either of them is impelled backwards, and retraces its path after the stroke. 3 ‘Cor, 1.—Hence if one of the bodies be.at rest before the stroke, the other will be at rest afterwards ; and that which was at rest will go on after the stroke with a motion equal to what the other had before. These things coincide with what we have deduced in our third proposition; but the proof here given is New Series, vou. . T 290 Mr. Herapath onthe Causes, Laws, and principal [APRiIt,) much more direct and rigorous than the one in that proposition ; for which reasons it will enable us presently to consider one or. two points of our theory that we could not before, at least in the manner we are now enabled to. Pe § Cor. 2.—The motions and directions of two balls being given, and the direction in which they strike one another being also given, the motions and directions of them after the stroke may be found. Let AC, B C, be the two given motions previous to the contact, and let E C F be the direction in which the balls strike. Upon E F let fall the perpendiculars A E, BF; and from the points E, F, draw E 6, F a, respectively equal and parallel to F B, EA; join aC, 5 C; and a C will be the motion of A, and _ 6 C that of B after the impulse. Cor. 3.—From this cor. it follows, that the compound motion of the bodies is the same before and after the impulse. For ..draw A D equal and parallel to C B, and join DC, which will be the compound motion of the bodies before the impulse. Likewise draw 6 A, Ba, and 6D. Then because E A, Fa, and -E 6, F B, are equal and parallel, A 6, a B, are equal and parallel; -and because A D, C B, are equal and parallel, 6 D, C a, are also equal and ei but by the preceding cor. a C is the motion of A, and 6 C that of B after the stroke ; D C is, therefore, the motion compounded of these motions. The same D C has also been shown to be the motion compounded of the motions of the bodies before the stroke; whence the motion compounded of the motions before the stroke is the same as the motion com- pounded of the motions after the stroke. Consequently,. the motion of the common centre of gravity of the bodies receives no change from the collision. Cor. 4.—The same inferences that we have drawn in the pre- ceding cor. might have been easily drawn from other premises. For since action and reaction are equal and contrary, the motion of each body is equally affected by the stroke ; and whatever is gained by the one in any direction is lost by the other in the same direction; so that the aggregate motion of the bodies in any direction is always the same, unless some extraneous force interferes, Scholium. Having now brought our theory of collision as far as it will be wanted in the subsequent part of the memoir, I shall omit the more intricate. problems connected with it, and shall only stop, before I proceed to the theory of gases, to consider another error in the old theory, and to clear up one or two points in the new, where, I think, from the novelty of the views and a natural prejudice in favour of preconceived notions, objections may arise. 1821.] Phanomena of Heat, Gases, Gravitation, &c. 291 According to the commonly received theory of collision, when a hard body strikes another at rest, the two bodies proceed toge- ther with a common velocity. Now if these bodies have no kind of attraction, they do not press after collision; and, consequently, either of them may be taken away without affecting the motion ofthe other. Hence the motion which the body that was quies- cent has acquired is proportional to the intensity of the impulse, and may be taken as a measure of it. Therefore, if the body A with a velocity of a strike the quiescent body B, the velocity of the balls after the stroke will, by the old theory, be <5, and the intensity of the stroke Cae The ball B and other things remaining the same, if, instead of A we substitute a ball m times naAB ng Wer te and there- fore the ratio of these two strokes is that of nA + Bton (A + B). That is, if two perfectly hard balls strike similarly and with equal velocities, two similar, hard, and equal balls, B, B, at rest, the ratio of the strokes will be that of zn A + Bto n (A + B). But by our first cor. to the preceding prop. the ratio of these intensities should be that of 1 to n; and the same is true by the third prop. The ratio of the strokes, therefore, as given in the two theories, differs materially. When the ratio of the stroke ofa less to that of a greater body, under the same circumstances of action is considered, it is greater in the old than in the new theory, and conversely ; and in all cases, except one; namely, the collision on a fixed plane, the intensity of the blow is lessin the old than in the new theory. It isnot an easy thing to examine the truth of either of these theories by direct experiment ; except, perhaps, in the case that I have mentioned in the scholium of prop. 2, for want of perfectly hard bodies to experiment on ; but probably, in the absence of experiment, the perfect coincidence of phenomena, and the consequences that I have drawn, from these new principles of collision in the follow- ing theory of gaseous bodies, will be admitted to amount, as nearly to an experimental proof as the nature of the subject allows. . Besides the methods we have adopted to consider various points in the collision of hard bodies, there are several others, alk of which, however, come to the same thing ; but the following method of examining the case of this schol. which has occurred to me while I have been writing this part of the memoir, appears to be so independent of previous considerations that I have been. tempted to give it. Setting aside all idea whether the bodies after collision do or do not continue together, let us only suppose that they are absolutely hard, that the two quiescent ones are perfectly equal, and that the other bodies before the strokes have equal velocities, and move similarly upon the quiescent , tT 2 greater, the intensity of the stroke would be 292 Mr. Herapath on the Causes, Laws, and principal [ArRit, bodies. Then because the bodies are perfectly hard, the strokes will be equally diffused, and felt in every part of the impingin bodies ; and, therefore, every part of the impinging bodies wi equally contribute to the stroke. And the same things will evidently hold good if each impinging mass, instead of being one entire body, be composed of two or more moving along in contact with a common velocity, provided the centres of gravity of all the bodies and their points of contact be all in the se in which the impulse is given. Again, because the bodies struck - are equal and similar, and the strokes are made similarly and with equal velocities ; the strokes, as far as they depend upon these - circumstances, must be identically the same. erefore, what- ever be the difference in the intensities of the strokes, it is wholly attributable to the difference in the masses of the impinging bodies. But we have already shown that the stroke is the same, under certain conditions, whether the impinging body be one or several bodies in contact. If, therefore, we conceive the greater impinging body to be composed of two, one of which is equal to the other impinging body, then, since the mere contact of the two parts can have no influence in augment- ing or diminishing the intensity of collision due to either of them separately, the intensity of the impulse of the other body, and of the part which is equal to it, are consequently equal. But because every part of the impinging body equally contributesto the stroke, the intensity of the impulse due to a part, whether that intensity be equivalent to the whole, or only to a portion of the momentum, is to the intensity due to the Whole of the body as the partis tothe whole. The ratio, therefore, of the impulses is sane to the ratio of the impinging bodies. en a hard ball strikes another hard ball at. rest, in the line of its motion, the effect of the collision is a mutual change of state. And since by cor. | to the preceding prop. this is true without regard to the relative masses of the balls : it follows that a body in a state of free and perfect quiescence, however small it might be, will destroy the motion of another body how- ever large and however great its momentum. Thus thena single particle of matter, of the smallest dimensions, to which a very small force would give a velocity sufficiently great to avoid a stroke from a very large body,. moving with a much greater momentum, may, if struck, when at rest, stop another of any dimensions and moving with any force. This conclusion, which, at first view, appears to throw an air of improbability over the theory, will, upon a closer inspection, be found to be perfectly natural and correct. For the effect in motion on either of the balls is equal to the intensity of the impulse, and that intensity, by the aforesaid cor. and by a variety of other considerations which it would be tedious to state, is equal to the momentum of the moving body. Itis, therefore, not on the relative magnitudes of the bodies that the change of motion depends, but on the { 1821.] Phenomena of Heat, Gases, Gravitation, &c. 293 momentum of the moving body before the contact; so that the effect of a very large body moving with a less velocity, may be equal to the effect of a very small body moving with a greater velocity. Hence the whole difficulty of this case turns upon the abstraction of the ideas of magnitude and momentum; and, therefore, if we admit a reciprocal change of state when the balls are about equal, we cannot refuse it in any other case. Again, it has generally been admitted that the relative motions of bodies, included in a given space, and their mutual actions on one another, are the same, whether that space be at rest, or move uniformly forward in a straight line. ‘This is true with elastic and soft bodies, and also with hard ones when they are equal because then their relative velocity is the same before and after the stroke ; but when they are unequal, it is very different. In cases where the masses are very unequal, the difference in the two results will, in general, be very great. Leta body whose mass is 8 and velocity 6 strike another at rest whose mass is 2 ; then the velocity with which these bodies separate after the stroke is 24. But if we estimate this relatively to a space mov- ing with a velocity of 4 in the same direction, it becomes 9, which is but little more than a third of the velocity, with which the two bodies do really separate. And the same anomalies might be shown to exist in other cases of this theory with respect to the collisions of unequal bodies under similar circumstances. — Itis, therefore, by no means immaterial, as it has generally been imagined (Newton, cor. 5, of the third Law of Motion), whether we calculate the effects of collision according to absolute or relative rest; the substitution of the one for the other might roduce very erroneous results. These considerations, however, will not at all affect the validity of our deductions in the laws of gaseous bodies. For the particles moving and striking in all directions, whatever force is gained by relative motion in the one is lost in the opposite direction; so that the mean force, which is all that we consider, will be the same in both cases (To be continued.) ARTICLE IX. On the Comparative Temperature of Penzance. By Dr. Forbes. (To the Editor of the Annals of Philosophy.) SIR, Penzance, Feb. 3, 1821, In the small tract lately published by me on the Climate of Penzance, I have pointed out the relative temperature of a ‘ : i \ 294 Onthe Comparative Temperature of Penzance. [Arnrit, variety of places in the island ; all which observations illustrate, in a very striking manner, the effect of the peninsular position of this place in equalizing its temperature. In further illustration of this fact, I subjom the principal results of the last three months at Penzance and Edmonton (Middlesex), as procured by the register thermometer. On this occasion I would beg leave to suggest the advantage of collecting the compara- tive observations made by register thermometers throughout the kingdom, and of publishing them monthly, condensed into a comprehensive and manageable compass, as in the following table. If you approve of the proposal, and will solicit the assistance of observers in different parts of the kingdom, I have no doubt but this will be cheerfully granted. By such a plan as this, I am convinced a much more clear and exact knowledge of meteorology would be diffused in a few years than by the long continued publication ofthe voluminous and unconnected diaries at present diffused through various journals. If your friend Mr. Luke Howard, who is, perhaps, better qualified for the task than any other person, would undertake to construct a plan, and submit it to the public, I have no doubt of the success of the measure. Of course, in this it would be necessary to include all the more important features of the science. In the following table I confine myself to the temperature. , Lam, Sir, your obedient humble servant, JOHN Forbes. Comparative Temperature of Penzance, in Cornwall and Edmon- ton, Middlesex, in Nov. and Dec. 1820, and Jan. 1821, by the Register Thermometer. | November. | December. | January. Penz, |Edm. | Penz. | Edm. | Penz. | Edm. Absolute maximum. .......... 56°} 58°} 54°! 56°} 53°) 53° Absolute minimum. .......... 35° | 22 | 21 | 21 | 26.) 21 Mean of maxima. ............ 50 | 47 | 46 | 48 | 47 | 41 Mean of minima. ws. des esse es} 44 1-35 |} 40 | 35 | 41 | 33 Mean of maxime and minima. ..| 47 | 41 | 43 | 39 | 44 | 37 Extreme monthly range. ...... 21 | 36 } 33 | 35 | 27 | 32 Maxi (wick . och 13 1-25 | 14] 19 | 12) 21 Diurnal range + Min.......... bit, Fae LpcBs oy ying: Mee a eR Sear eet? N.B. The results for Edmonton are extracted from the diary of Mr. Adams, published in the Literary Gazette. 1821.] Mr . Hanson’s Meteorological Results for Manchester. 295 6 adeeb eeat O6I-FI | 691-08] 109-18] 181] OGT-2E 6I | &&| FE) 99) €-6F |S11/L-Eh| 3¢-0 (SI-f 01-62! 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[APR1L, - The annual mean temperature is nearly 494°, being a little more than 1° less than the mean of last year. The mean of the first three months, 38°5°; secord, 54:4°; third, 59°9° ; fourth, 44°5°; of the six winter months, 41°5°; six summer months, 57°1°. The maximum of 83° occurred on June 27, and the mini- mum of 13° on Jan. 1: difference of these extremes, 70°. The mean annual pressure of the atmosphere is 29°70 inches ; highest point, 30°64 ; which occurred on Jan. 8 ; lowest, 28°45, which was on Oct. 17: difference of these extremes, 2°19 inches. The mean daily movements of the barometrical oscillations. mea- Sure nearly 44 inches. Total number of changes, 112. The falls of rain, hail, snow, and sleet, durmg the past year, have measured a little more than 32 inches ; which is something under an annual average. Very little rain fell during the first three months of the year; but the following month (May) was very wet, for there were nearly six inches registered. Upwards ‘ of four inches fell in October. Total number of wet days for the year, 181. e reporter, as usual, has again to notice a prevalency of the south, south-west, and west winds. Out of 365 notations of the wind, 214 were noticed to blow from the above points. There has been more thunder and lightning, during the former part of the year, than has been noticed in several former ones, particularly in the month of May. Lightning occurred-on six days in that month, which were invariably attended with rain : sometimes it fell in torrents, and in three instances with hail. My friend, Mr.-Edward Stelfox, of Lymn, near Warrington, has favoured me with the above account of rain. Mr. 8.’s rain- guage is exactly the same as mine, and | can rely upon his account as correct. His annual register of rain, for the year 1819, was 29°305 inches ; for the present, a little more than 30 inches. Mr. Stelfox noticed the temperature on Jan. 1, 1820, to be 13°5°; on the 3d, at 13°; and on the 22d of the same month at 10°, The colamn of rain, headed Ardwick, has been furnished by my friend, Mr. John Dalton. His rain funnel is fixed about a mule out of Manchester, in an easterly direction, and is situated some little higher than mine. It has often been remarked, that Mr. Dalton’s annual account invariably exceeds mine sometimes by five or six inches, as in-the present instance. Mr. D. thinks that his funnel being larger may in part account for the difference. However, I fancy, there is an error somewhere. It is much to be desired, that one uniform plan could be adopted with respect to measuring of rain. I have furnished a gentleman of Crumpsall, near Manchester, with a funnel, and the same means of measuring the rain as Mr. Stelfox uses: and, from his results, it appears, that our accounts pretty nearly agree. Manchester, Jan. \7, 1821. ‘ cal Journal for Cornwall. 297 t 1821.] Mr. Giddy’s Meteorolog "eB Jo aingerodursy ukoMt ay} 38 peyepnozeo SE LO}OWLOIN OUT, % G2 |29| AAN|6LISFIS9\S1/09 LE|OS|PE163s|LE1/ 1-91] PS-9 [18-6 | 9 | SI) FB | 8} SL +O0¢ | SS | GF | SE9-0] 110-1] €59-62! 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Ss¢-63] 1¢6-62|" °° * ISNBN_ 0\t | as (6 O jt 1 |ELG {Et |g |Fo jh | 18-1 |0¢-0 |1s-1.] 9 | OL | VL | Se | SL | €9 | 99 | 19 JOSE-0) bF8-0| 699-6a| 01-62] SF6-62]"°°*** Ame 0 |p |MNIFIIS If | [¢ ‘0 \0 |9 |s@ |L 108-0 | 92-0 49-0 | L | 1 | $3 | OF | TL | 19 | LO | SE 1212-0) 869-0] LOS. 6a! <3E-62| 960-0)" °° °°" BUNS 0 lg |MS {3 JF [LUO It 9 10 IL lat [61 189-1 | oF-0 1ea-1 | 8 | HE | 361 OF | 89 | 9G} B9 |} FE |90¢-0! CO0-1| 13ag-Gsl LE6-8z 066-62/"""*"* SoM 0 3 |MN/Z1/6 |1 0 9 1 € |g [SS |L 169-0 | 0-0 |¢¢-0 | 6 | 91 | FB | OF | FY | Sf | LE | SF leLE-0/ 861 1/8L9-62| B16-82/ OT L-06| "°° THdy I |r| Mig iL jo 13 [6 & |F Is [FS IL | 19-01 210-0 |4¢-0 | 8 | 61 | BE | OF | 29 | 9F | OF | Br jOsF-O}.09s-1| 169-62] O6L-82| OSO-OF|** ** “WIE BY 1/9 |MN{S 0 |¢ € |§ # (E |e [PS |G | EL-0 | 68.0 |2F-0 | 9 | FT | $6 | OF | GS | SF | LY | OF |808-0| t69-0| SOL-6a| F9E-62/ 860-06" * “Arenagqa.z ¢|L | AS js ¢ [Ss 1 8 LI lg |St [él | 40-8 | 02-1 |t8-0 | F | 8 | FE | BB [GE [068 JoIF | ol€ | 9SF-0| SEC-1| 009-62] 861-82] 96E-08|"** ‘Arenuer de ti A gw awa isl mo] oe isl Oe Ole | ee OO) ed SB eb oe ta ees 42 Bla |a 2 e+ oS = ZBlz S's Bi) eiel | elas] as. 3 = e Seis | + “Elered | Bol Ble? ele gle | EDP IE bestes| ? : * |) 4.) 5 s/< er) oe Pale sis sl] o ee 62/3 3 alF| a wana Spe a eh 2 e| & | a | E pig Gee a “| & ee * # | ‘duta} Jo *rvA |somenx ye “due; ueoyy [Aprit, We find, therefore, the same relation between ‘the protoxide of iron and the barytes, as in the salt with base of potash; on the other hand, the relation of the water to the bases exhibits, in this instance a remarkable exception to the ordinary rule, ao exception that might very well be attributed to inaccuracy of observation, if the loss which this salt experiences by efflores- cence were not so uniform and so easy to be correctly deter- mined. When we compare the relation of ‘the capacity of — saturation of the bases, to the quantity of the substance lost in the analysis, with that observed in the salt with base of potash, ‘we find, in the salt with base of barytes that the loss exceeds that in the salt with base of potash by a quantity precisely equal to that which the water wants (que l’eau.a donné en moins).to make its oxygen twice * that of the barytes, and six times that of the protoxide of iron. We shall soon see that this water is found again, when this salt is burned by means of oxide of copper. ’ is (C,) Salé with Base of Lime. : This salt was prepared nearly in the same manner as the barytic salt. It is very soluble in water, and does not crystallize till the solution has acquired a syrupy consistence, and after some days rest. The crystals are usually large, and of a pale ellow colour. . ABU TO One hundred parts of this salt, exposed to the heat of a sand- bath, lose 36°61 per cent. of their weight of water of crysvalliza- tion. The crystals, notwithstanding this large quantity of water, do not fall to powder, and I have observed that although this salt begins to effloresce as readily as the preceding, a wigher temperature is requisite to deprive it of the last portions of water. The anhydrous salt, burnt like the preceding in an open vessel, gave 50°53 per cent. of its weight of a mixture of oxide of iron, caustic lime, and carbonate of lime. It was dissolved in muriatic acid, perfectly neutralized by caustic ammonia, and recipitated by succinate of ammonia. The succinate of iron, Leanad on an open capsule of ora left 15°25 parts of oxide of iron. The solution, from which the iron had been separated, gave, by precipitation by oxalate of ammonia, oxalate of lime, which, being decomposed by heat, left 59-21 parts of carbonate of lime. This carbonate, moistened with a solution of carbon- ate of ammonia, and then thoroughly dried, gained nothing in weight. The analysis, therefore, gave . Oxygen. Tame. ..42% »oeee 22°45 contaming 6°20 ..... 2 Proxide ofjiron. .. 18°69 owed dep PIS 0. of Water oe ee we eree 39°61 cledeweces 36°21 over phe pS a 23°85 : ly ae ‘ah * Query, three times, 1821°] - the Composition of Prussiates. 305 We find again here, as in the barytic salt, that half a propof- tion of water is wanting, that is to say, that the salt retains one atom of water; and:by comparing the loss from the substances destroyed by heat, with the capacity of saturation of the bases, we also find in this case a surplus corresponding to the quan- tity of water that has disappeared. | (D.) Salt with Base of Oxide of Lead. Neutral nitrate of lead was poured into a solution of ferruginous prussiate of potash, taking care that the latter. should be in excess, In order to prevent the precipitation of nitrate of lead, which mixes with all the insoluble salts with base of oxide of Jead, if there be an excess of nitrate of lead in the liquid from which they are deposited. The liquid remained perfectly neu- tral... The precipitate was white, but viewed in a certain diree- tion towards the light, it appeared verging to-yellow. I was unable to determine, with the precision I could have wished, the quantity of water contained in this salt, because its point of -perfect dryness approaches too near to that at which it begins to effloresce.. owever, the results: I obtaimed led me ‘to. believe that in this salt, just as in the salt with base of potash, the water contains the same quantity of oxygen as the two’ bases together. : Bi One hundred parts of the salt, dried on a very hot sand-bath, were burned in an open porcelain capsule; the mass was dis- solved in nitric acid, neutralized with ammonia, and precipitated. ‘by sulphate of ammonia.’ The sulphate of lead, washed, and «alcined at a red heat, weighed 96°5 parts. The filtered liquid was precipitated by caustic ammonia, and gave 12:6 parts of oxide of iron. ‘Thus the analysis gave: Up) | Weer / . Oxygen. Oxide of lead ........ 70°0 containing 5:09 .... 2 Pipeosine of spon PS VT ee ee en ok Bae PO VAES | chk this thd ton: We find, therefore, also in this case, the same relation between. ‘the oxide of iron and that of lead, as well as between the bases ‘and the substance destroyed by combustion, as in the ferrugi- nous prussiate of potash. . I think these analyses, selected from the three classes of bases, ~will suffice to prove that whatever be the state of the iron in these salts, it takes, in the state.of protoxide, half as much oxygen as the radical of the other base. : II. Expertinents on the Acid of these Salts. The proofs on which Mr. Porrett has founded ‘his. opinion, that the iron in the ferruginous hydrocyanic acid is in the metal- New Series, vou. 1. U 306 . Professor Berzelius on; [ArRin, lic state, and that it is a constituent part of this acid, are not decisive. . | To verify this idea by direct experiment, I put 23°16 grs. of effloresced ferruginous prussiate of potash, into a small appa- ratus, made by the lamp, and so disposed that a current of sulphuretted hydrogen gas might be passed over the salt. At the common temperatures it was not at all altered. I then heated it by a spirit-lamp, slowly increasing the temperature until the mass fused. The sulphuretted hydrogen gas was passed over it until the mass became cold. I had supposed that the sulphuretted et would decompose the protoxide of ion, producing hydrocyanic acid, water, and sulphuret of iron ; ‘but no trace of water appeared.. The sulphuretted hydrogen, doth at entering into, and leaving the apparatus, was passed aver fused muriate of lime, in order that the water, that might be formed during the operation, might be correctly weighed. At the end of the experiment, the prussiate had gained 116: per «ent. in weight, and the muriate of lime 21 hundredths -of the “weight of the prussiate. But on heating the muriate of lime, to see if what it had absorbed, was water, 1t gave off only hydro- sulphuret of ammonia, and pure ammonia, with traces: of mois- ture. No disoxidation of the protoxide of iron, therefore, had taken place, and. the experiment. appeared to confirm Mr. Porrett’s idea. A great part of the salt had been converted into’ sulphuretted. hydrocyanate of, potash;.a small portion remained. undecomposed, and:'some sulphuret of iron was formed. 3 cies hosilan bias onic ot 7 I next endeavoured to decompose the anhydrous prussiate by distilling it with fused boracic acid, to ascertain if, during this ‘operation, borate of iron would be formed ; but the mass swelled up greatly during the process, and:passed out of the retort, so that its neck was soon stopped up by it. The disengaged gas was cyanogen, mixed with a little hydrocyanic acid. After the cal- cined mixture had been dissolved in water, a brownish mass remained, insoluble in muriatie acid, which, exposed to heat, gave borate of iron ; whence it appeared that the boracic acid Ahad been in part decomposed. _ Thus the nonoxidated state of the iron seemed proved by these ‘experiments. When I calculated the above-mentioned analyses, the result appeared to coincide with the following composition : one atom artic iron, two atoms of the Aide of the other ‘bases, two atoms of cyanogen, and three atoms of prussic acid. At thus remained to determine by combustion, if that be the true state of the matter. vty In consequence, I burned, in a glass tube surrounded by ano- — ther of tin-plate, a mixture of 7°72 grs. of anhydrous ferrugi- nous prussiate of potash, and 231-66 grs. of pure oxide of copper, prepared by the decomposition of, nitrate of copper by heat. “Lhe mixture was made ina porphyry mortar, heated to above 1821.] the Composition of Prussiates. 307 212° Fahr. © The gases were collected over mercury, and passed through tubes of very small diameters to prevent too great a mix- ture of atmospheric air. A portion of the gas obtained towards the end of the operation was collected separately in a graduated glass tube. : No moisture condensed in the tubes, in which, for greater cer- tainty, a portion of fused muriate of lime was placed, and weighed with the tubes. They gained only 0-001 in weight. The gas collected in the graduated tube was examined in the following manner : a small piece of caustic potash attached to a very thin flexible iron wire was introduced into the tube; 100 parts of the gas left 39-9 parts not absorbed ; ‘so that the volume of carbonic acid gas was to that of the azote as 3:2. This result was very different from what I had expected. As no water was formed in the operation, it followed, that the salt contained n hydrocyanic acid. Mr. Porrett had found that the volume of ‘carbonic acid gas was four times greater than that of the azote, and Dr. Thomson obtained them in the ratio of 2} to 1. The whole ofthe carbonic acid obtained in this experiment, absorbed’ by a determinate quantity of potash, weighed 4°138 grs. { repeated the experiment once more, but with a stronger heat, so as to soften the glass tube; I obtained the same result, but the relation of volume of the carbonic acid gas to that of the azote then exceeded the ratio of one and a half: however, the difference was so trifling that it might very well be only an error - of observation. Water digested on the residuum in the tube that had been exposed to heat, took up potash, and this solution gave an abundant precipitate with lime-water ; the precipitate was car-— bonate of lime. To prove if the difference between my result and that of Mr. Porrett could be caused by a bad arrangement of my apparatus, I repeated the analysis of the cyanuret of mercury in the same manner ; I obtained from it precisely two volumes of carbonic acid gas for one volume of azote ; and on decomposing another portion of cyanuret of mercury by sulphuretted hydrogen gas, in a weighed glass bulb, I obtained sulphuret of mercury, whose weight was to that of the cyanuret of mercury, precisely as the weight of an atom of cinnabar, is to the weight of an atom of cyanuret of mercury. ! This accordance with the results obtained by M. Gay-Lussac, satisfied me that the difference between my results, and those of Messrs. Porrett and Thomson cannot be attributed to my appa- ratus being less suited to the purpose. | I next repeated the same analysis with the ferruginous prus- siate of barytes, previously dried at a strong heat. It gave traces of moisture in the tube which conducted the gases into the receiver, although its quantity was not great : 15°444 ors. of the salt employed gave 0°026 of a grain of water, precisely the quantity wanting, in the analysis mentioned above, to make the v2 308 Analyses of Books.) [Arrin, oxygen of the water of crystallization amount to’six times that of the protoxide, of iron, presupposed in the salt, instead. of five times and a half. The volume of the carbonic. acid, gas ebtained in this experiment was again to that of the azote, as 3:2, and the whole ofthe carbonic acid obtained weighed 6:25. ..No conclusion can be drawn from, these experiments before the quantity of carbonicjacid retained by. the base is determined. If the azote and the carbon in these salts be in the same propor+ tion as im cyanogen, one-third of the quantity. obtained, or. one- fourth of the whole of the carbonic zcid, is wanting. Butif, on the contrary, the base remaining in the calcined mass be in the state of common carbonate, the volume. of carbonic acid is to that of the azoteas 21; 1. | (To be continued.) oe ARTICLE XV. » ANALYSES oF Books. A Chemical and Medical Report of the. Properties of the Mine- ral Waters of Buxton, Matlock, Tunbridge ‘Wells, Harrogate, Bath, Cheltenham, Leamington, Malvern, and the Isle oe Wight. By Charles Scudamore, MD. Member of the Royal.College of Physicians, &e. &e. Hh 2 gan oF | ‘ke In noticing this work, I shall, of course, confine my observa- tions to the Chemical, part of it, and I shall admit as proved, without making any inquiry, or expressing any doubt, that their medicinal qualities render these waters worthy of being drank ; and there then can be no. hesitation as to the importance ofa perfect, knowledge of their chemical constitution, whether it may or may not enable us to. account for the beneficial effects wags every day’s experience would lead us, to believe that they proauce, iy tC ; . ‘The analysis of the Buxton water appears to call for a few observations. I think the method) employed to determine the presence of magnesia ambiguous, and the, means used to ascertain the anata, of magnesian salt rather tedious. The plan adopted by Dr. Scudamore for ascertaining the presence of magnesia was that proposed by. Dr. .Wollaston,, of first adding carbonate of ammonia, and then phosphate of soda to the water. Now I haye found that the salt usually called.carbonate of am- monia, and which is, in. fact, a sesquicarbonate, always. holds some carbonate of lime in:solution ; and this is particularly likely: to occur when carbonate of lime exists in a mineral.water, so ee a Dr. Scudamore on Mineral Waters. 309 that the addition of phosphate of soda may throw down phos- ) mp of lime, as well as the phosphate of ammonia and magnesia. ‘Whether any ‘difficulty occurred to Dr. Scudamore on this a¢- ‘count im determining the quantity of magnesia, he does not mention, but I think it probable; for the method.by which. Te determined’ the quantity of magnesia was that of decomposing the muriate obtained from the: alcohohe solution, by means of carbonate of soda, then ‘adding sulphuric acid to the carbonate ‘of magnesia, suffering the sulphate of magnesia to crystallize by slow evaporation, and agaim decomposing the el pre by cai- ‘bonate of soda, and decomposing the carbonate of magnesia by heat, and then calculating the quantity of muriate of magnesia ‘which it would yield. a rT From some late ‘experiments I am imduced to believe that lime water is not only the best test (with certain precau- tions), but also the most eligible substance for obtaining the magnesia from a mineral water. Me » Supposing no alkaline carbonate nor any alumina to exist in a ‘water, and that the oxide of iron has been separated, lime water will discover an extremely minute portion of magnesia, when the saline contents of the water have been obtained by evaporation and redissolved in distilled water: Thus, I find that the twelfth: part of a grain of magnesia, and even a much smaller quantity, may be readily shown to exist in a pint. of water, and is easily precipitated from combination with an acid by lime water. The only inconvenience to be avoided, is the possibility that the excess of lime water used, may deposit carbonate, if the air be not carefully excluded during the filtering and washing of the precipitate. It is, however, but due to Dr. Scudamore to state that I have found magnesia actually existing in this water, but which I did not believe to be the case until [ read his work, and even when Thad, I doubted as to the accuracy of his statement. My sus- picions of the Doctor’s inaccuracy were indeed strengthened by an experiment which he relates, and which I had tried with si- milar results, viz. that lime water occasions. no precipitate in Buxton water which had been boiled: this experiment induced me to believe that the water contained no magnesia; but, on evaporating a portion to dryness, and redissolving the saline re- siduum in water, a precipitate of magnesia actually occurred. It will not be surprising that lime water did not indicate the mag- hesia in the water without concentration, when it is stated that the whole quantity which a gallon contains amounts to only about 0-16 of a grain. [have considered this part of the sub- _ ject merely with a view of determining the best methods of detecting the presence of magnesia; for I will hazard the ) Sn mre that in a medicinal point of view, the 0°16 of a. grain of magnesia, however combined, cannot. possess any very ex- tensive influence when dissolved in a gallon of water.’ The 310 - Analyses of Books... [Arrit, whole weight of the saline contents of a gallon of Buxton water amounts to fifteen grains ; my experiments make it ra- ther less; but I am inclined to think that Dr, Scudamore has stated the chemical analysis of this water with great ac- curacy. : | In the analysis of the Tunbridge waters, I think Dr. Scudamore has been rather profuse in the application of the tests to indicate the presence of iron: thus, after observing an evident ochery deposite, the unequivocal action of tincture of galls, we have the confirming evidence of prussiate of potash, and sulphuretted hydrogen, which are again rendered doubly sure by the infusion of tea and coffee, whilst with cocoa or chocolate no action ap- pears. Now with all deference, I submit, that these last ob-. servations might have been spared, as they serve merely to com- licate the subject, and are devoid of any particular interest, orl have never heard of the application of Tunbridge water in preparing food. ) he quantity of oxide of iron, obtained from Tunbridge water, Dr. Scudamore states to be 2°22 grains ; it is not, perhaps, a matter of much importance, but I may observe that this quan- tity of iron is rather over-rated, for it was weighed in the state of peroxide, but ought to have been reduced to that of protoxide, . in which iron always exists in mineral waters ; this will make the quantity of oxide about 1-99 grain. | | The analysis I shall next notice is that which Dr. Scudamore has given of the Bath water: this water I analyzed about seven- teen years since; and, as well as every StoeRdine and following analyst, I failed to ascertain the presence of magnesia, now shown to exist in the Bath water by Dr. Scudamore; my error arose from employing ammonia, on the supposition, which I did not then know to be erroneous, that this alkali would throw down minute quantities of magnesia. I have, by employing lime water i the mode already pointed out, ascertained the correctness of this author’s statement. It appears that a pint of the water contains, however, only about 1:6 grain of muriate of magnesia. } In other respects there is no very material difference between _ ‘Dr. S.’s analysis and mine ; but I may observe that he committed -a slight error in supposing me to have stated, that iron cannot be detected in the Bath water after it has cooled; what I have .- shown is, that if cooled without the presence of oxygen or at- mospheric air, it retains its property of being acted upon b tincture of galls and showing the presence of iron ; it is, indeed, upon this circumstance, that the peculiarity of the Bath water, -as far as regards its chalybeate impregnation, depends. The only remaining analysis which I shall notice is that of the “Malvern water ; some discussion has arisen between Dr. Philip, who formerly analyzed this water, and the author of the present work, as to whether this water contained any iron, , Operating Dr. Scudamore on Mineral Waters. ° 31F in the usual way, I should certainly coincide with Dr. Scuda- more, for it appears to me that neither tincture of galls, nor prussiate of potash, produces any appearance of iron. ‘The ques- tion has, however, been set at rest by Mr. Children, who finds that, by evaporating the water, a very minute portion of iron is discoverable by prussiate of potash; but whether that quantity of iron, which cannot be detected by the common means, is likely to be useful in medicine is not for me to determine, but L may, perhaps, be allowed to question it. ‘The quantity of iror contained in a gallon of Malvern: water, according to Mr. Chil- dren’s experiments, scarcely exceeds one seventieth of a grain. Some ‘difference of opinion also exists between Dies Belida- more and Philip as to the existence of carbonate of soda in it: I evaporated a portion both from Holywell, and St. Anne’s Well, to about 1-30 of its origimal volume, but I could not discover the slightest trace of any alkali. It appears, therefore, to me that Dr. Scudamore’s statement is correct. In closing my ob- servations upon this work, I wish to state that I cannot admit, with Dr.’ Scudamore, the position laid down by the late Dr. Murray, that when certain acids and alkaline bases are mixed together in solution, such salts are most likely to be formed as are most soluble in water. If I put together certain quantities of sulphate of soda, and muriate of lime, precipitation takes place, because sulphate of lime is formed ; but is it likely that, as this theory supposes, the whole of the sulphate of lime formed is thrown down? Indeed, if I understand Dr. Murray’s position, it amounts to this—that supposing I mix together sufficient quantities of muriate of lime and sulphate of soda, to form one hundred parts of sulphate of lime; that sulphate of lime will only be formed if there be not water enough to hold it in solution; but this would seem like attributing the property of insolubility to a compound before its formation. / Pass It has, indeed, been attempted to strengthen this statement by arguing from the effects which certain mineral waters pro- duce, or are supposed to produce, and which, according to com- mon views, contain only sulphate of lime and muriate of soda ; these waters are imagined to owe their good effects to con- taining not sulphate, but muriate of lime. It would, however, Lc think, require numerous experiments to prove that the same — quantity of lime is more active as a medicine when combined with muriatic than sulphuric “acid; when exhibited in equal quantities. -1 do not deny, but I question the fact; and if it should be proved, it may,-as far as’ I am competent to give an opinion, be derived from the muriatic acid as from the lime. i have not, in examining this work hitherto, expressed any decided opinion as to its merits; but 1 may add, that the chemical part of it appears to ‘have been conducted with ability ; and if the medical ‘applications of the waters, have been as ably giver as the chemical history, (of which I entertain’no doubt,) the work must prove’useful both‘to the chemist and’ physician. — Ed, ‘ 312. Proceedings of Philosophical Societies. [Aprit, Articte XVI. ~ Proceedings of Philosophical Societies. | ROYAL SOCIETY. March 8.—On the Length of the Second’s Pendulum in. dift ferent Latitudes, by Capt. Sabine. ” : | March: 15,—Observations on Napthalin, by Dr. Kidd. | . March 21.—On the Papyri of Herculaneum, by Sir H. Davy. _ At the same meeting two other papers were read, viz. On the Aberration of compound Lenses, by Mr. Herschel; and On the Skeleton of the Dugong, by Sir E. Home. Sci . An account of the contents of the above papers will be givem in the next number. | 7 : GEOLOGICAL SOCIETY. __ Jan. 14.—The Catalogue Raisonnée. of the Collection of Swiss ocks, sent by M. Lardi, was read. : _ The great valley comprehended between Mount Jura and the Alps, and which forms the lowest part of Switzerland, is com- _ posed partly of an alluvium, and partly of a sandstone and pud- dingstone, in Switzerland, called Nagelflue, which signifies. literally nail-head-rock. The alluvium consists of insulated masses of primitive rocks, rolled pebbles, and debris, from the surrounding mountains ; in this are also beds of clay. The nagelflue may be divided into two parts; the molasse and the nagelflue, properly so called. The first is a sandstone used for building in that country ; it is disposed in horizontal beds alternating with beds of marle, which sometimes contain marine shells and veins cf fibrous gypsum: the lower part. has: beds of fetid bituminous limestone with freshwater shells, and. thin layers of coal. , | . The nagelflue consists of a conglomerate of rounded. pebbles. of limestone united by a cement of the same nature ; it forms a mass of 30 or 40 feet in thickness, and contains also beds of marle, and, occasionally, of coal. This appears to rest upon the . calcareous rocks of the Alps. y | The greatest part of Mount Jura ‘consists of calcareous rock,, which is usually compact, and of a yellowish colour ; some of the beds are oolite. It incloses numerous marine shells. The beds. of Jura dip on both sides of the chain. There is found here also a formation of clay ironstone, which extends nearly all the length, of the Jura, and which supplies many foundries. — _ The Alpine limestone is considered as:a transition formation ;, it is of a compact texture, of a greyish colour,, and. frequenth contains nodules of flint, It rests on another limestone which alternates with slate. bi dhw te) ** signcits: eid’ 2 .. The saliferous district of Bex has, been well described by M., W2h} a oie Astronomical Society. ox 313 Charpentier. It-belongs to the transition formation, and rests at Lavey on primitive rocks.,. It.is) composed chiefly ofa lime» stone, of which we distinguish twovarieties ; one is compact and eolitic,.sometimes, containing much silex; the other is an argil+ laceous limestone. It, is in the last that the gypsum of the environs of Bex is situated. . This gypsum is generally in the state of anhydrate, and presents several varieties. It is usually - impregnated. with muriate of soda, and sometimes contains beds of hydrous gypsum in the state of selenite ; the fine crystals of which, from this: place, are very celebrated. Native sulphur is also found... The beds subordinate to the gypsum are argilla- ceous limestone and slate clay. | Between, Morcles and Lavey commences a transition formas tion, consisting of felspathic rocks, clay slate, and breccias, or uddingstone... This country is little known. | Nearly the whole ength of the Valais, a formation of clay slate extends : it cons tains also beds of limestone, of gypsum, and of quartz. Above Oberswald are found rocks of gneiss, mica slate, clay slate, dolomite,and gypsum. These constitute the mountains of the Fourche of St. Gothard, and the superior part of the valley of the Tessin. | At Lago di Lugano, a blackish-brown porphyry is met with; consisting of hornstone with small crystals of white felspar. ASTRONOMICAL SOCIETY. OF LONDON, _ At the commencement of the last year this interesting and important Society was founded. Although, at that time, we omitted the expression of our gratificatiun on account of its forma~- tion, and even neglected to announce it, yet we fully participated with the cultivators of the science of astronomy in their enthusias- tie expectations of the decided and powerful influence of this as- sociation upon its future progress. Indeed it had always appeared to us to be somewhat extraordinary, that while chemistry, | geology, and several branches of natural history, were promoted and extended by associated bodies, a science, which, from the vastness of its objects, and the extent and difficulty of its obser- vations and investigations, demands in the highest degree, the powerful aid of this concentration of intellect, should so long have been left to rely for its advancement on the laboars of insu- dated and imdependent individuals: That this desideratum for astronomy will now be effectually supplied, cannot be doubted by those who have perused an exposition of the views and objects of the Society, in an address circulated prior to their first meet- ing, and:a list of members affixed to the report presented by the Council to the first annual general meeting. Although the last; we boldiy predict, that the Astronomical Sodiety will not. be the least, in the career of utility and fame. — : Without entering too much into detail, we may, by an extract from the admirable address. before alluded to, sufficiently display 314 Proceedings of Philosophical Societies. [Aprit, the enlarged views and liberal feelings ‘of the promoters of this design. “ One of the first great. steps towards an accurate knowledge of the construction of the heavens, is an acquaintance with the individual objects they present: in other words, the formation of a complete catalogue of stars, and of other bodies, upon a scale infinitely more extensive than any that has yet been undertaken; and that shall comprehend the most minute objects visible in good astronomical telescopes. ‘To form such a cata- logue, however, is an undertaking of such overwhelming labour as to defy the utmost exertions of individual industry. It is a task which, to be accomplished, must be divided among num- bers ; but so divided as to preserve a perfect unity of design, and prevent the loss of labour which must result from several obser- vers working at once on the same region, while others are left unexamined. The intended foundation of an observatory at the southern extremity of Africa, under the auspices of the Admi- ralty, may serve to show the general sense entertained of the importance of this subject, and the necessity of thle, hb possible perfection to our catalogue.of the fixed stars. Deeply impressed also with the importance of this task, and fully aware of its difficulty, the Astronomical Society might -call upon the observers of Europe and of the world to lend their aid in its prose- cution. Should similar institutions be formed in other countries, the Astronomical Society (rejecting all views but that of benefit- ing science) would be ready and desirous to divide at once the labour and the glory of this Herculean attempt, and to act in concert together in such manner as should be judged most con- ducive to the end in view.” The following summary with which the address concludes, may be quoted in order to convey at once a distinct representation of the purposes of this Society. ‘‘ The objects of the original members may be sufficiently gathered from what has been already said, and may be thus summed up in few words; viz. to encourage and promote their peculiar science by every means in their power, but especially—by collect- ing, reducing, and publishing, useful observations and tables— by setting on foot a minute and systematic examination of the heavens—by encouraging a general spirit of inquiry in practical astronomy—by establishing communications with foreign obser- vers—by circulating notices of all remarkable phenomena about to happen, and of discoveries as they arise—by comparing the merits of different artists eminent in the construction of astrono- mical instruments—by proposing prizes for the improvement of particular departments, and bestowing medals and rewards for successful research in all;—and, finally, by acting as far as pos- sible, in concert with every: institution, both in England and abroad, whose objects have any thing in: common with their own; but avoiding all interference with the objects and interests of established scientific, bodies.” » yh? hag ih On the/ninth of February) the first-annual general meeting of- 1821.] Astronomical Society. 54 315 the Society was held ;. and the following gentlemen were elected officers for the year ensuing ;_ viz. President.—Sir W. Herschel, LLD. FRS. Vice-Presidents.—H. T. Colebrooke, Esq, FRS. & LS. S. Groombridge, Esq. FRS. D. Moore, Esq. FRS. SA. & LS. : J. Pond, Esq. Astronomer Royal, FRS. Treasurer. —Rev. W. Pearson, LLD. FRS. Secretartes.—C. Babbage, Esq. MA. FRS. L & E. F. Baily, Esq. FRS. & LS. J. F. W. Herschel, Esq. MA. FRS. L & E. (Foreign.) : Counctl.—Capt. T. Colby Roy. Eng. LLD. FRS.L & E. Sir H.C. Englefield, Bart FRS. L& E. FSA.& IS. Davies Gilbert, Esq. VPRS. and FLS. B. Gompertz, Esq. FRS. O. G. Gregory, LLD. J. Rennie, Esq. FRS. L. & SE. A & LS. J. South, Esq. FRS. . KE. Troughton, Esq. FRS. Trustees.—A. Baily, Esq. D. Moore, Esq. FRS. SA. & LS. C. Stokes, Esq. FRS. SA. & LS. The Treasurer for the time being. To this meeting an elegant and elaborate report was presented by the Council, which, having been adopted by the Society, was ordered to be printed. After congratulating the members on the success which has attended the first attempt to establish a Society for the promotion of so important.a branch of science as astronomy, and stating that the efforts of its founders have been crowned with an accession of strength far beyond their most sanguine expectations, the Council proceeds to announce a plan of distributing medals, as an honorary reward, to such per- sons as may distinguish themselves by any material discovery, or improvement, in the science. The following extract will exhi- bit some of the subjects selected for the application. of these stimulating. rewards. ‘In the first place, it is proposed to bestow the medal for the discovery of any new planet, satellite, or comet ; or for the rediscovery of any old comet, or of any stars that have disappeared. Considering also the great importance (both in a nautical and geographical point of view) of having accurate observations of the eclipses of Jupiter’s satellites, and of occultations of stars by the moon, they think that the medal _ Should be given for any considerable collection, not only of ori- ginal observations of this kind, but also of well authenticated re- corded observations, reduced to the mean time of the meridian of - some well known observatory. Observations likewise on the posi- > 316 Proceedings of Philosophical. Societies. [Ar RID, tions of the fixed stars, tending either to the enlargement and per- _ fection of our present catalogues, or tio the more accurate determi- nation of the variable ones,in size, colour, or situation ; as well as observations on double: stars, tending in like manner not only to the enlargement. and perfection of the present catalogues, but also to the determination of their angular distance and of their angle of position; together with observations om nebule,—appear proper subjects of such reward. To these may be added, observations on refraction, with a view to the more perfect theory of that phenomenon, particularly at. low altitudes where irregularities take place, when: little or no variation has taken place in the barometer or thermometer ; observations on the tides, particu- larly im situations where the current is not influenced by any contiguous continent; observations tending to determine the true figure of the sun, or of the earth ; and, in short, any obser- vations which may be considered likely to advance and improve the science.” . uty Having mentioned several other subjects, such as the reduc- tion of observations when made; the formation of various new tables, and the improvement of others; the comparison of the places of the planets; the examination of the recorded observa- tions of preceding astronomers; and every improvement of instruments which may tend materially to advance the science, for which the Society’s, medals will be bestowed, the Council proceeds to recommend the proposal of the gold medal, and twenty guineas for the solution of the following question ; a ques- tion requiring the synthetic application of the Newtonian doc- trines, together with the highest refinements of modern analysis : ‘“« For the best paper on the theory of the motions and pertur- bations of the satellites of Saturn. The investigation to be so conducted as to take expressly into: consideration the influence of the rings, and the figure of the planet as modified by the attraction of the rmgs, on the motions of the satellites : to furnish formule adapted to the determination of the elements of their orbits, and the constant coefficients of their periodical and secu- Jar equations, from observation : likewise to point cut the ‘obser- vations best adapted to lead toa knowledge of such determination. The papers to be sent to the Society on or before the first day of February, 1823.” | The Council, however, while thus taking advantage of the stimulus to inquiry which medals and prizes produce, have esta- blished, in the following impressive sentences, their claim to the possession of a full sense of the magnificence of their science, and the comparative insignificance of their rewards: “It may indeed ee extraordinary that no mention should yet have been made of the great desiderata of astronomy; those questions which have exercised the curiosity and employed the time and attention of astronomers, ever since the science has assumed its ~ : e 182L.).° Astronomical Society. 317 present character—sueh as the-parallax.of the fixed stars, their proper motion, the motion or rest of our own system, and: its connection with the rest of the universe. But these and many other points, are too obviously suggested ‘by their importance to need any particular notice or encouragement. The man for whom discoveries of this class are reserved, soars far beyond any distinction which this Society can bestow: the applause of the human race’attends his labours ; and no additional! stimulus can be offered to those by which he is impelled.” cen In consequence of a communication from Captain Basil Hall, expressing his readiness to attend to any instructions on subjects wherein he might be of service to the science of astronomy in his intended voyage to the South Seas; the Council have delineated with great minuteness and.imgenuity, their wishes in regard to his undertaking. ‘The formation of an Astronomical Library, one of the objects of the Society, is then noticed; and the donations by the East India Company of many valuable papers on astrono- mical subjects, and of a series of observations made at the Observatory at: Madras, are acknowledged. ‘The alteration of several of the regulations; the appointment. of Committees for various purposes; the notice of the discussion of a plan for examining the heavens in minute detail; and. the, state- ment.of the constant accession and unqualified approbation of the continental astronomers, constitute the remaining topics of this report; which thus coneludes: ‘ On the whole, the Council cannot view this new impulse which appears to have been given to astronomy in all parts of the world, without anticipating the most beneficial results to the science. The establishment of several new Observatories on the continent of Europe (one of them above the sixtieth degree of north latitude) under the direction of men eminent in’science, and vieing with each other in the most honourable branch of emulation—the rising efforts of our countrymen in the East Indies—the zeal of our brethren on the American continent—the foundation ofa public Observa- . tory at Cambridge, and another at the Cape of Good Hope (both so honourable to our own country)—must ensure the good wishes of every friend to science, and excite the admiration of every veflecting’mind.” : © - | ein | oe! ArtTicLye XVII. NEW SCIENTIFIC BOOKS ~ AN . _ PREPARING FOR PUBLICATION, > An Analogical Inquiry into the probable Results of the Influence ot Factitious Eruptions in Hydrophobia, Tetanus, Non-Exanthematous, and other Diseases incidental to the Human Body, illustrated by Cases. oe 318 ~ New Patents. — [APRIL, ~ Dr. Clark Abel is preparing a Translation from the German of Blu- menbach’s Elements of Natural History, comprehending considerable Additions. : ~ . Observations on some of the General Principles, and on the Parti- . cular Nature and Treatment, of the different Species of Inflammation ; by J. H. James, Surgeon to the Devon and Exeter Hospitals, &c. __ An Essay on Resuscitation, with a Representation and Description of an improved ie yeh By T. J. Armiger, Surgeon. . Thomas Hare, FLS, &c. intends to publish a View of the Structure, Functions, and Disorders of the Stomach, and Alimentary Organs of the Human Body, with Physiological Observations and Remarks upon the Qualities and Effects of Food, and fermented Liquors. JUST PUBLISHED, ‘ Practical Observations on those Disorders of the Liver, and’ other Organs of Digestion, which produce the several Forms and Varieties of the Bilious Complaint.. New and enlarged Edition. By Joseph Ayre, MD. 8s. 6d. bds. . Observations on Syphilis. By John Bacot. 8yvo. 5s. A Treatise on the Epidemic Cholera of India. By James Boyle. Svo. 5s. " ‘A Treatise on the Medical Powers of the Nitromuriatic Acid Bath in various Diseases, with Cases. By Walter Dunlop, Surgeon. 8vo. 2s. ~ Jilustrations of British Ornithology. By P. J. Selby, Esq. Member ofthe Wernerian Natural History Society at Edinburgh. First Series, Land Birds, No. I. Elephant folio, 1/. 11s. 6d. coloured 5/. 5s. Elementary Illustrations of the Celestial Mechanics of Laplace. Svo. 10s. 6d. boards. ArticLe XVIII. NEW PATENTS. ~ James Ferguson Cole, of Hans-place, St. Luke, Chelsea, for certain improvements in chronometers.—Jan. 27, 1821. ~~ John Roger Arnold, of Chigwell, Essex, for a new or improved ex- pansion balance for chronometers.—Jan. 27. Alphonso Doxat, of Bishopsgate-street, for a new combination of mechanical powers, whereby the weight and muscular force of men may be employed to actuate machinery for raising water, or other pur- poses, in a more advantageous manner than has been hitherto practised, communicated to him by a certain foreigner residing abroad.—Jan. 27. Phillips London, the younger, of Cannon-street, practical chemist, for a certain improvement in the application of heat to coppers and other utensils.—Feb, 3. William Aldersey, of Homerton, for an improvement on steam- engines, and other machinery where the crank is used.—Feb. 3. George Vizard, of Dursley, Gloucestershire; for a new process or — of dressing and polishing goods of woollen manufacture.— eb. 3. . 1821:] Mr. \Howard’s, Meteorological Journal. 319 ArtTIcLE XIX. “METEOROLOGICAL TABLE. eee Baromerer,| THERMOMETER, . Hyg! at 1821, Wind. | Max. | Min. | Max. | Min. Evap. | Rain.| 9 a.m. 2d Mon. sated Feb. 118 W/30°36'30°21)° 52° | 44 — 63 4 2] W__130°32)30-21).50, | 31.) — 80 1@ 8} W_ |30°25'30°03| 48 39 oe Wg? | 4| W_ |30°62:30°03) 44 25 lem | FO 5IN W/30°74:30°62| 39 Q4 ee 67 6|S ...W/|30:76,30:6@) ..42..|...27-.).o— 60 7|\S W({30-69'30°61}. 45. | 27.) —. 68 —8| «S 180-61/30-25) 49° | 21 fe (5S 9} -Var.. 130°30)30'11} 45°" | °° 29 — (3° HE -10\N __ E)30°37,30:30) 46.) . 28.5}.. =: 73 ‘TUN ~~ E/30-37'30°30! 945 27 — 61 12N E)30°33'30-28| 40 | 32 | — 80 13IN E/30°33'30 28} 39 a0. toe kb 66 14] Var: '130°38'30°98) 34°). 31 le 5A 15IN... .E/30°53|30°38|...35-.).- 2b) se! 74 16IN E/30°53'30°41; 38 | 26 |. — 71 1718 = E/30°41/390°94) 33° | 26 oe 80 I8IN W/\30:33|\30°20|)..39..}. 27... 4... jm} OF FQ 19IN W/(30:33'30°30} 40 22 — 66 Q20\N.. W30:31.30°17 AQ 4 + GO| -eeered- OBI o> GQ 211N W/30'32 30°21 40 | 27° | — 79 22/8 ---- B}30-32;30°30} 42°} 20° 65 23|N W/)30°30)30°2 | 37 20 oe 76 —24IN W130:2130°15} 37. | 24 —, 91 “BIN TW 30°15 30°14 44 | 32 | | SP 79 /26| E |30°14:29°92) 35 is — - 66 } 27/5 E/29:92 29°45 38 ee ee ee 62 f@ - 2381S » EiQ9-44, 29°33 37 fe Sben| & 6524 223 cH $0°76.29°33 52 18- | 1/07. |.0°31|, 91—55 The observations in each line of the table apply to a period of twenty-four hours, A dash denotes that ‘beginning at 9 A. M. on the day indicated in the first colum i. the result is included in the next following observation. - 320 Mr.. Howard's Meteorological Journal. TArrit, 1821, _/ REMARKS. | ~ Second Month:+-\, 2 Fine. 3, Fine: cloudy. 4. Overcast. 5. Fine: hoar frost in the morning. 6. Hoar frost. 7. Hoar frost : very fine morning: lunar corona at night. 8. Hoar frost; fine. 9. Hoar frost: cloudy: fine. 10, Cloudy. 11, Cloudy: fine at intervals, 12—15, Cloudy. ©16;‘Zimnar corona. 17. Cloudy. 18, Fine: a shower about 10, p.m. 19. Fine. 20. Hoar frost: a shower in the evening. 21. Cirrocumulus and Cirrostratus streaked, like an agate. 22. Hoar frost. 23,/24. Hoat'frost: foggy. 25. Cloudy. 26, Cloudy ; bleak. 21,.Very fine morn- ing, 28. Snowy. . i 7 ’ _ RESULTS. : —" \ ‘ : ae of sean: NE, 6; E, 1; SE, 45 8,1; SW, 3; Whi NW, 8; Var. 2, Bote: Mean height W For the montDenssserseserseneseitectanteatnedde . 80°272 inches. For the lunar period, ending the Vth. seeeererer-e. 30336 re Li iet For 14 days, cing he Eh 00m) + vane 30-404 ) - . For 18 days, om. the 18th (moon north) .. ° vetegess - 30°395 Thermometer: Mean height Ob 8-08. cE OBA For the month. . Ppom® se eegan es tnenerinsenaget s49¥7 34-2140 va chaps Usaa.|..28 0 0 s\eddiawde bMahe +» B55 For 29 days, the sun in Aquarius, , fF a tee ad ee . 36 ‘TAL Evaporation. , . ere ee wees eseees iowa oe f Bis i QERE ERD 1-07 i In. / Rain. eee eee ee eee ee eee ee eee ee) oe essacees ee ree eres O-3sL ~ ’ a . aaa ; : > e rf i ¥¥ Mean of hygrometer. | ...++-eeeseeeses Lye TAR eeeeee aoe s opiiah=- 2+ BM The barometer, which has ranged very high most part of this winter, has twice risen go in the last and present month as probably to reach the upper extremity of the scale in wens instruments, as it did in one of those which we observed. © ¢ «*« The Comet, which is now visible, was well seen at Tottenham ‘by my brother and other persons as early as the evening of the 234 ; ; and ‘on the 27th, the Zodiacat Light was also distinctly observed there. Laboratory, Stratford, Third Month, WV, A821. - R. HOWARD. ANNALS OF PHILOSOPHY. MAY, 1821. ARTICLE I, Observations on the Combinations of Azote and Oxygen. By Thomas Thomson, MD. FRs. ScARCELY any part of chemistry has been investigated with - more industry than the various proportions in which oxygen and — azote combine. This is partly to be ascribed to the beautiful simplicity which such combinations exhibit, partly to the appa- rent facility of experiments on the union of deutoxide of azote and common air, and partly to the notion entertained by Dr. Priestley and his contemporaries, that common air varies in the proportion of oxygen which it contains, that its state of salu- brity depends upon this proportion, and that the degree of its goodness is easily determined by means of deutoxide of azote. Chemists in general are now agreed about the number of compounds of azote and oxygen, which are capable of being formed ; and, with the exception of Mr. Dalton, they are agreed likewise about the exact proportions in which they unite. Mr. Dalton, in a very elaborate paper, published in the ninth volume of the Annals of Philosophy, p. 186, has given us a great number of experiments, from which he draws the following conclusion: the five compounds of azote and oxygen, if we consider both of the constituents in the gaseous form, are composed of Volumes. . Volumes. 100 azote + 62 oxygen, constituting protoxide of azote’ 100 +62 x 2 = 124 deutoxide of azote 100 + 62 x 3 = 186 hyponitrous acid 100 + 62 x 4= 248 nitrous acid 100 +62 x5= 310 nitric acid New Series, vou. 1. x | 322 Dr. Thomson on [May, Gay-Lussac, in a paper published in an early volume of the Annales de Chimie et de Physique, has given very strong reasons for concluding that the composition of these five com- pounds is as follows : Bu fa Fs es Azote. ' Oxygen, Protoxide of azote. ....... 000. 100 volumes -+ 50 volumes Deutoxide of azote, .......... -- 100 + 100 Hyponitrous BONG «hy OM etl Bae «ae 100 + 150 Nitrous acid... oseeesees es waite BOD eat S200 Nitric acid, W..04 Ah. Ch oe A OF F E4850 As far as I know, these proportions of Gay-Lussac have been adopted Xf whole chemical world, with the exception of Mr. Dalton. My object in this paper is to show that the present state of our knowledge leaves no. doubt whatever that Gay- Lussac’s proportions are accuraté, and that, Mr. Dalton has misled himself somehow or other. 1. I take it for granted that the specific gravity of oxygen and azotic gases are as follows : of protoxide:of azoté\is 15277. Now we have 1 volume.of azotic gas = 0:9722. + volume of oxygen gas = 0°5555) | 15277, Thus when a volume of azotic gas is united to half'a volume of oxygen, andthe two condensed into oné volume, a gas is formed which possesses’ exactly the specific gravity of protoxide of azote. Hence we are entitled to conclude, that protoxide of azote is a compound of one volume azotic + half'a volume of oxy- gen gas condensed into one volume. That this is its true com- position is obvious from the following experiment, which I have often made; and which very nearly: agrees with the results given long ago’by Davy in his Researches. 2 Mix together 100 volumes of protoxide of azote end 100 volumes of hydrogen gas. Pass an electrical spark through the mixture; detonation takes place, the: whole hydrogen gas disappears, the residual gas measures:exactly 100. volumes; and is pure azotic gas. Thus we see’ that. 100 volumes of protoxide of azote contain exactly 100 volumes of azotic.gas. The! 100 volumes of hydrogen gas must have been converted into water, and for this conversion they must’ have united with 50 volumes - t 1821.7) the Combinations of Azote and Oxygen. 323: of oxygen gas; consequently 100 volumes-of-protoxide of azote contain exactly 50: volumes of oxygen gas. The only difficulty attending this: experiment is: to procure protoxide of azote in a state of absolute purity. I have fre- quently had’ it so’ pure that the error in; the results| did not amount to so much as. half per cent.. This 1. consider as.a demonstration that: Dalton’s proportion: of; oxygen, which: he makes 62 volumes, is excessive. Were this, the: quantity, 124 volumes of hydrogen gas would. be) requisite instead. of 100 volumes ; and after burning amixture.of: 100-volumes of protox+ ide of azote and 100 volumes of hydrogen,.a:portion of protoxide of azote (amounting to rather more? than: 20,volumes) should remain undecomposed; or 12. volumes; of oxygen .gas should be found'in' the residual gas; which, instead: of 100, volumes, would amount to 112 volumes. | ; If, Mr: Dalton will consider these facts,, he will, I think, see the necessity of admitting» that protoxide of azote is a compound of 100: volumes azotic: + 50 volumes oxygen: gas. condensed into 100 volumes:. 3 2.. That deutoxide: of azote: is: a; compound;of 100) volunies azotie + 100 volumes oxygen gas united together, and consti-. tuting 200. volumes;. will notvadmit of doubt,. if'we attend. to its specific gravity, which I have shown to be 1:04166 (Annals of Philosophy, xvi. 172.) Now.thisis‘exactly the mean‘ of the spe- cific gravities ofoxygen-and azotic gases ;: for: - Oxygem.... @. 0 @.0:.@@ie® PyPCy Nets S © @.@¢ 616 = lll Azotie. 08 6 0 06 0 eee e Oene eee O08 woe 09722) ates 2)2-0833. Mean. Ore 0 8 1ere e888 iD OO OR Be we Oe: = 1:04166 { have not myself made any experiments to determine the uantity of oxygen in deutoxide of azote by combustion; but diteneniakeoian adduced by Gay-Lussac in the second volume of the: Memoires: d’Arcueil, that’ this. gas is. composed. of. equal volumes of oxygen and azotic gas, is-so conclusive:as. to leave no doubts whatever on my mind of its truth. 3. I have attempted to verify Gay-Lussac’s. experiments, in which: he made one volume of oxygen gas: unite’ with four volumes of deutoxide of azote ; but though I have returned to the subject more than once at different periods of the year, I have never been so fortunate as to obtain the same results. with that very ingenious philosopher. I have, however, succeeded in: hitting upon a method by. which this. combination can be accomplished at all times with the greatest.ease.. Indeed I have since found that this method is not new. It was practised by Mr. Cavendish as long ago as 1783, and is minutely described : oe / 324 _ Dr. Thomson on [May, by him in his well-known paper, entitled “ Of a new Eudiome- ter,” (Phil. Trans. 1783, p. 106). It is, therefore, rather singular, that this method, which is easy and exact, seems to be quite unknown both to Mr. Dalton and M. Gay-Lussac. The method is this : Put into a small glass vessel open below 100 volumes of deutoxide of azote. Into a small cylindrical glass vessel having a small brass stop cock at its top, and a brass plate (with a small hole in it) fixed to it by grinding below, put 100 volumes of common air. Sink the cylindrical vessel under water, and lace the vessel containing the deutoxide of azote over it, tak- ing care that its mouth is under the surface of the water. Things being in this situation, open the stop. cock. The common air will make its way slowly, and bubble by bubble, into the deutoxide of azote. Agitate the vessel containing the deutoxide of azote the whole time that the common air is enter- ing into it. Ifyou measure the residual gas after the process is at an end, it will amount at an average to 96 or 97 volumes; so that the quantity of gas that disappears when the experiment is made in this way amounts to 103 or 104 volumes. Now 100 volumes of common air contain 21 volumes of oxygen gas ; so that 82 or 83 volumes of the gas which have disappeared are deutoxide of azote and 21 volumes oxygen gas ; but 21 : 83 23) 100:: 395:2. | | In this mode of experimenting then, 100 volumes of oxygen gas unite to 395-2 volumes of deutoxide of azote. Now 395:2is only about one per cent. less than 400. I conceive, therefore, that there can be no doubt when the experiment is made in this way, that 100 volumes of oxygen. gas really unite with 400 volumes of déutoxide of azote. ? . Deutoxide of azote consisting of equal volumes of azotic and oxygen gases united without undergoing any condensation, it is. obvious that 400 volumes of it must be composed of 200 volumes oxygen 200 volumes azotic gas Therefore, when 100 oxygen unite with 400 deutoxide of azote, the compound formed is in reality composed of 200 volumes azotic and 300 volumes oxygen; or, wehsich is the same thing, of 100 volumes azotic + 150 volumes of oxygen gas. Now this is ‘the compound called hyponitrous acid. . i have never attempted to collect this acid in order to examine its properties, ‘the great quantity of water with which it was diluted in all my experi- ments precluding the possibility of obtaiming it. But as this mode of experimenting gives uniform results, | see no reason to doubt that such a substance as hyponitrous acid actually exists. 4, 1 have never found any difficulty in obtainimg a compound of-100 volumes oxygen and 200 volumes of deutoxide of azote. My method of proceeding is this: I intreduce 100 volumes of common air into a ¢ylindrical glass tube, the internal diameter 1821.] the Combinations of Axote and Oxygen. 325 of which is 0-9 inch. This tube is shut at one end and open at the other, and being filled with water is placed inverted on the shelf of the water trough. A hundred volumes of deutoxide of azote are let up to the common air. The mixture becomes yel- low, and diminishes rapidly in volume. I allow the tube to stand untouched till the gas has become clear, and till it ceases sensibly to diminish in bulk. I then introduce the residual gas into a graduated tube, and measure its volume. The average residue, when the experiment is made in this way, is 137 volumes. The following table exhibits the residual volume in six successive experiments, the original volume of the two gases being 200. | Volumes. 136 137 137 138 136 137 Mean.... 136°8 Thus it appears that when the experiment is made in this way, the gas which disappears, and which of course must have been converted into an acid and absorbed by the water, amounts to 63 volumes. Now 21 of these volumes must have been the oxygen contained in the 100 volumes of common air, and the remaining 42 volumes must have been deutoxide of azote ; but 42 is just double 21. Thus we see that when the experiment is made in this way, one vclume of oxygen combines with two volumes of deutoxide of azote. This is the same thing as 100 volumes of oxygen and 200 volumes of deutoxide of azote; but 200 volumes of deutoxide of azote are composed of 100 volumes oxygen, 100 volumes azotic gas, consequently the acid formed in this case is a compound of 100 volumes of azotic and 200 volumes of oxygen gas. Itis, there- fore, the acid known by the name of nitrous acid. | Dulong has shown that this is the acid which is obtained when nitrate of lead is exposed to heat in a retort; while the receiver is sur- rounded with a mixture of snow and salt. It is an acid of a pale-yellow colour, and seems to undergo decomposition when united to the bases. From Dulong’s experiments, it appears to contain no water. Indeed nitrate of lead, when properly dried, is free from water. 3 5. IL have not yet hit upon a method of uniting 100 volumes of oxygen with 133 volumes of deutoxide of azote. Davy first showed, that if we unite these two gases in these proportions, 326 Dr..Thomsonon. [May, the resulting compound will be nitric acid. Ihave tried, the experiments, which he describes, but find the results too varia- ble ‘to place any reliance.on them. But. it is not. difficult to demonstrate that nitric acid is in reality a compound of 100 volumes.azotic and: 250 volumes of oxygen.gas, | In the Annals of Philosophy, xvi. 334, 1 have shown by a aye but, decisive experiment, that the atomic weight of nitric acid.is 6°75. The preceding observations leave no doubt that the composition of protoxide of azote, deutoxide of azote, hypo- nitrous acid,.and nitrous acid, is as follows : | Azote. Oxygen. Protoxide of azote...... 100 volumes + 50 volumes Deutoxide of azote...... 100 + 100 or 50 x 2 Hyponitrous acid. ...... 100 + 150 or 50 x 3 Nitrous acid. .......... 100 _ + 200 or 50 x 4 We cannot avoid concluding, from observing these proportions, that these different substances are composed as follows : Azote. Oxygen, Protoxide of azote .......caeee -. lL atom + 1 atom Deutoxide of azote... .......0000: 1 + 2 Hyponitrous acid. 2.2.0... 1 +3 Mitrons eid. 6270. POSSE ouite 1 +4 Consequently an atom of azote is represented by a volume of azotic gas and an atom of oxygen by half a volume of oxygen gas ; but the specific gravity of azotic gas is 09722, and that of oxygen 1:1111, the half of which is 0:5555; therefore, the weight of an atom of oxygen is to that of an atom of azote as 0°5555 to 09722; but 5555: 9722 :: 1: 175; consequently, if an atom of oxygen be represented by 1, ‘an atom of azote will weigh 1:75. Substituting these weights for the atoms in the ahs. table, we obtain the atomic weights of these different bodies as follows : ‘ Protoxide of azote. .... eave ide SS 2°75 Deutoxide of azote. ..0. 0... uk, Bie ee 8°75 Hyponitrousracid ii. .e ee ieee. AS75 Nitrous! acitlixs 426 wiiete. la easel 5°75 if to 5°75 we add another atom of oxygen, we obtain 6°75. Now this is the weight of an atom.of nitric acid. It.cannot be doubted, therefore, that nitric acid isa compound of five atoms of oxygen and one atom of azote. But as,an atom of azote represents a volume, while an. atom of oxygen represents half.a volume, it is evident that nitric acid must be a compound of 18219 the Combinationsiof Azoteand Oxygen. ‘327 Azote. ' “Oxygen. — - 100 volumes + 250 volumes. Now this is the very constitution pointed out by Davy and by Gay-Lussac. 6. About the year 1806, Mr. Dalton published a set of experi- ments to determine the proportion of the several gases in the atmosphere.* In this paper he remarks, that if 36 volumes of _ ‘pure deutoxide of azote be introduced into a'glass tube about three-tenths of aninchwide; and 100 volumes ofcommonaimbe let/up intoiit, ‘after a:feweminutes*the:wholewill be reduced to ‘79 or 80:volumes, and will exhibitno signs of eitheroxygen, ‘or deutoxide of ‘azote. » Incthis ‘case, 21 volumes: of oxygen have anited with 36: volames: of deutoxide of azote: | 1f the same expe- riment: be» made in a wide vessel, a common tumbler, for mstance, and if we employ 72 volumes .of ‘deutoxideof azote and 100 volumes of common air, the residue will -be-as ‘before, 79 or'80 volumes. Thus 21 volumes of oxygen unite with 36 volumes of deutoxide of azote.in a-narrow tube, and with 36 x 2 = 72 volumes,in a wide vessel. This is. equivalent to Oxygen. Deutoxide of azote. 100 volumes -+ 171°429 volumes 100 +. 342°858 The. diminution of volume in. a‘narrow tube he finds so con- stant that he recommends this mode of experimenting as a good method of detecting the volume of oxygen.in a given quantity of gas. Take a given volume-of it, andlet up into it a given volume of deutoxide of azote., Note the-diminution of volume ;-7-19ths of this diminution.is the oxygen required ;.so that, according to this rule,.we have only tormultiply the dimiution of volume by 0:3684; the product is the volume-of oxygen required. | I have made.a greatomany trials to verify these conclusions of -Mr.: Dalton. . Indeed 1,adopted, his mode of determining the proportion of oxygen im mixed:gases by:means, of deutoxide of ‘azote -as,soon as L.became acquainted with it; butthe want of coincidence between different trials, though made im precisely the same way, led:me. at last:to:doubt-its precision, and. to make a set of experiments in order to investigate what really takes place. I found, in the first place, that the results did not vary sensibly, whether we employed glass tubes of the bore 0:3, 0°4, or0-5inch. My mode of proceeding was to put 100 volumes of common air into a graduated tube, and to let up into it 100 volumes of deutoxide of azote. After the diminution of volume was at an end, | noted the volume of residual gas. The follow- ing table exhibits the volume of residual.gas in six successive experiments made in this way in a tube of 0:5 inch in diameter : # Phil. “Magy xxiii, 351. 328 Dr. Thomson on , [May, Volumes. 138 140 144 142 144 142 The mean of these trials gives a residue of 141-6 volumes. The . smallest residue was 138, and the greatest 144. The mean volume of gas which disappeared in this case was 58°4. Now of this, 21 volumes were oxygen gas, the remainin 37°4 volumes must have been deutoxide of azote ; so that the mean of these experiments gives us 21 volumes of oxygen unit- ing with 37-4 volumes of deutoxide of azote. Thisis only avery . little greater than 36 volumes, the quantity assigned by Mr. Dalton. The extremes in the experiments are : Volumes. Volumes. 21 oxygen + 35 deutoxide of azote - 21 + 41 : These variations are so great that I was induced to abandon Dalton’s method altogether. I find that a tube 0°9 inch in diameter gives much more correct results. When we employ it, the 21 volumes of oxygen just unite with 42 volumes of deutox- ide of azote; so that the oxygen is obtained by dividing the diminution of bulk by 3. It is obvious that 36 volumes of deut- oxide of azote is not the minimum quantity with which 21 | volumes of oxygen gas are capable of uniting. The minimum, instead of 36, is in reality 28 volumes. I have obtained a dimi- nution not exceeding 51 volumes, when I employed very narrow tubes ; but the process is disagreeable, and not nearly so accu- tate as when we use tubes with a diameter of 0°9 inch. When we mix common air and deutoxide of azote in a com- mon tumbler over water, the results are pretty uniform. The following table exhibits the volume of residual gas when 100 volumes of deutoxide of azote were let up into 100 volumes of common air in a tumbler about three inches in diameter : 119 119 118 118 118 118 —_— Mean.... 1183 In these experiments, the mean diminution of bulk was 81} eee | SALVEVE ALY DIMAS pou hugs sol ssmpb yo emo. ong Crcnempuo y hoy, BO ansereeeESoe SEE CE SE orcreneT 4 | | ee ) | : , + : “er (\" soda ee | oecnnee if > > “gy blom pun sion ag Aq posrodiaguna bung youm 743 'sUTy - LS i ~muvd.gnoryn $4 0N0.4 Y dao YW Dy JO SMOLY AR 2D 09 YAM Uae, ( rea, ee a, Sops or metal whih rnite the Copperin each teil with the tro in the neat. 1821.] . the Combinations of Azote and Oxygen. 329 volumes. Of these 21 were oxygen; so that 21 volumes of oxygen had united with 60:6 volumes of deutoxide of azote. This differs materially from 72 volumes which Mr. Dalton states as the maximum of deutoxide of azote which unites with 21 volumes of oxygen. ' My experiments were all made without agitating the vessels, which no doubt diminishes the portion of deutoxide of azote which disappears when agitation is used. My results approach very nearly to one volume oxygen, and three volumes deutoxide of.azote. Such a compound would consist of 1-5 volumes azotic,. ne 2°5 volumes oxygen. This is equivalent to bh oa \ilael 1 volume azotic, lz volume of oxygen, which is the same as l atom azote + 31 atoms oxygen... This is obviously no definite compound, though it approaches nearest to hyponitrous acid, | ! _ Avery great number of experiments which 1 have made upon ~these combinations during the course of the last 15 years leave no doubt whatever on my mind that both Mr. Dalton’s minimum and maximum of deutoxide of azote are inaccurate, and that in “reality | volume of oxygen may he made to combine with 1, 2, and 4 volumes of deutoxide of azote, producing nitric acid, nitrous acid, and hyponitrous acid, respectively. The two gases _ ean combine in all the intermediate proportions between these: ~ Hence the great variety of results, and the apparently capricious _hature of the experiments, that have for so many years attracted ‘the attention of the chemical world.. ! ARTICLE I. A Memoir on some new Modifications of Galvanic Apparatus, with Observations-in Support of his Theory of Galvanism. By R. Hare, MD. Professor of Chemistry in the University of Pennsylvania. Communicated by the Author. (With a Plate.) I wap observed that the ignition produced by one or\two galvanic pairs attained its highest imtensity, almost as soon as they were covered by the acid used to excite them, and ceased soon afterwards ; although the action of the acid should have - increased during the interim. I had also remarked in using an apparatus of 300 pairs of small plates, that a platina wire, No. 16, placed in the circuit, was fused in consequence of a construc- tion which enabled me to plunge them all nearly at the same time. It was, therefore, conceived, that the maximum of effect ae. lent as 330 Dr. Haye’s new Galvanic Apparatus, Dheory, &c. [MAx, in yoltaic. apparatus of extensive. series had never been attained. The plates are generally arranged, in; distinct troughs, rarely containing more than.20 pairs. . Those of the great apparatusof the Royal Institution, employed by Sir H. Davy,; had only 10 pairs in each. There were 100 such to be successively,placed an the acid,.and the whole connected ere the poles, couldjact. Consequently the effect which arises. immediately after; immer- sion would be lost in the troughs. first. arranged,. before it could -be produced in the last; and no effort appears to haye.been made to take advantage of this transient accumulation of power, either in using that magnificent combination, or in any other of which I have read.. tn order:to observe the consequence of simultaneous immersion with a series sufficiently numerous’ to test the correctness of my expectations; a galvanic apparatus of 80 concentric coils of copper and zinc was so suspended by a beam and levers as that they might be made to descend into, .or rise ouit of, the acid in an instant. The zinc sheets were about nine inches by six, the copper fourteen by six; more of this metal being necessary, as in every coil it was made to commence within the zinc, and completely to surround it without. ‘The sheets were coiled so as not to leave between them an interstice wider than a quarter of an inch. Each. coil is in diameter about two inches and a half, so that all may descend freely into 80 glass jars two inches and three-quarters diameter inside, and eight inches high, duly stationed to receive them.* My apparatus being thus arranged, two small lead pipes were - severally soldered to each pole, and a piece of charcoal about a — quarter of an inch thick, and an inch and a half long, taperinga little at each-extremity, had these severally inserted into the hollow ends of the pipes. The jars being furnished with diluted acid, and the coils suddenly lowered into them, no vestige of the charcoal could ke seen. It was ignitéd’so intensely, that those portions of the pipes by which it had been embraced were destroyed. In order to avoid a-useless' and tiresome repetition, I will here state that the coils were only kept in the acid while the action at the poles was at.a,maximum,in the experiment just mentioned ; and in others, which I-am about to describe; uniess ~where the decomposition produced by) water is spoken of, or the ‘sensation excited in the hands. , 1 designate \the apparatus with — which [ performed them as the galvanic deflagrator, on account -of its superior power, in:proportion to its size, in»causingidéfla- gration ; and as, in» the form last adopted, it) ditters ‘from the voltaic pile in. the omission of one of ithe elements heretofore deemed necessary torts construction. 7 , Desirous of seeing the effect of the simultaneous immersion of my series upon »water, the »pipes soldered tothe) poles were 4ntroduced into.a vessel containing thatfluid. »Novextraordimary — O® See Plate VIL. 1821] Dr. Hare’s new Galvanic Apparatus, Lheory, §c. B31 effect. was. perceived, until they were very;near, when a vivid flash was| observed, and,happening to. touch almost at the same time, they were found. fused and.incorporated at the place of contact. Inext-soldered to each. pipea brass, cylinder. of about. five-tenths.of.an,ineh bore. ‘These cylinders .were made. to receive the tapering extremities of a,piece of charcoal about. two inches long, so as to complete the circuit. The submersion of the coils caused the most vivid ignition, in, the.coal. It was instantaneously and-entirely onfire. A. piece cf platina of about a quarter of an inch diameter in connexion with one pole, was instantly fused at the end on being broughtin contact with some mercury communicating with the, other. When two cylinders of charcoal, having hemispherical terminations, were fitted into - the brass cylmders and brought nearly into. contact, a most vivid. ignition took place, and: continued.after they were removed ahout a half or three quarters of an inch apart, the interval rivalling the sun in-briliancy. The igneous fluid appeared to proceed from the positive side. The charcoal in the cylinder soldered to the latter, would be intensely ignited throughout, when the piece connected with the negative pole was ignited more towards. the extremity approaching the positive. Lhe most intense action seems to arise from placing a platina wire of about the emghth.of an inch diameter, in connexion with the. positive pole, .and bringing it im contact with, and. afterwards removing it a small distance apart from, a piece of charcoal (fresh from the. fire) affixed to the other pole. : , As, points are pre-eminently capable, of carrying off (without. ‘being injured) a current of theelectrical fluid, and very il quali- fied to conduct caloric; while, by facilitating radiation, charcoal favours the separation of caloric from the electricity ‘which does. not radiate ; this result, seems:consistent with my hypothesis, that the fluid-as extricated by Volta’s :pile.is.a compound of caloric and electricity ;*. but: not with the other hypothesis, * According to the theory here alluded to, the: galvanic fluid owes its properties to \caloric and electricity, the former predominating in proportion to the-size of the pairs, ‘the latter in proportion to the number, being in both cases excited by a powerful acid. ‘Hence in batteries which combine both qualifications sufficiently, as in allithose mter- vening between Children’s large pairs. of two.feet eight inches by six feet, .and the. 2000 four-inch pairs of the Royal Institution, the phenomena indicate the presence of both fluids. In De Lue’s column, where the size of the pairs is insignificant, and the energy _ of interposed. agents feeble, we see electricity evolved without any appreciable quantity of caloric. _ In the calorimotor where »we: have: sizevonly, the number being the lowest possible, we are scarcely able to detect the presence of electricity. _. When the fluid contains enough electricity to give a projectile power adequate to pass “through’a small space in the air, or through charcoal, which impedes or arrests the calo- ric, and: favours its propensity to radiate, this principal heat is evolved, ‘This. accounts for the evolution of intense heat under those circumstances which rarifies the air, so that » the length of the jet from one pole to the other may be extended after its commence- ‘ment. \ Hence the portions of the circuit nearest to the intervening charcoal, or heated ‘Space, are alone injured ; and even*non-conducting bodies, as quartz, introduced into ait are fused,. and hence a very large ‘wire. may be melted. by the fluid, received through a small wire imperceptibly affected. See Silliman’s Journal, No. 6, vol. i.; Thomson’s Annals, Sept. 1810; Tilloch’s Philosophical Magazine, Oct,.1819,. 332 Dr. Hare’s new Galvanic Apparatus, Theory, §c.. (May, which supposes it to be electricity alone. The finest needle is competent to discharge the product of the most powerful machines without detriment, if received gradually as generated by them. Platina points, as small as those which were melted like wax in my experiments, are used as tips to lightening rods without injury, unless in sudden discharges produced under peculiar circumstances.* ! The following experiment I conceive to be very unfavourable ‘to the idea that galvanic ignition arises from a current of elec- tricity. A “ilindies of lead, of about a quarter of an inch diameter, and about two inches long, was reduced to the thickness of a com- mon brass pin for about three-quarters of an inch.. When one end was connected with one pole of the apparatus, the other remained ‘suspended by this filament; yet it was instanta- neously fused by contact with the other pole. As all the calo- rific fluid which acted upon the suspended knob must have passed through the filament by which it hung, the fusion could not have resulted from a pure electrical current, which would have dispersed the filament ere a mass 50 times larger had been perceptibly affected. According to my theory, caloric is not separated from the electricity until circumstances very much favour a disunion, as on the passage of the compound fluid through charcoal, the air, or a vacuum. In operating with the deflagrator, I have found a brass knob of about five-tenths of an inch in diameter, to burn on the superficies only ; where alone, according to my view, caloric is separated so as to act on the mass. Having, as mentioned in the memoir on my theory of galvanism, found that four galvanic surfaces acted well in one recipient, I was tempted, by means of the 80 coils, to extend that construction. It occurred to me that attempts of this kind had failed from using only one copper for each zinc plate. The zinc had always been permitted to react towards the negative as well as the positive pole. My coils being surrounded by copper, it seemed probable, that if electro-caloric were, as I had sug- gested, carried forward by circulation arising from galvanic pola- rity, this might act within the interior of the coils, yet not be exerted between one coil and another. I had accordingly a trough constructed with a partition along the middle, so as to receive 40 coils on one side, and a like num- ber on the other. This apparatus, when in operation, excited a sensation scarcely tolerable in the backs of the hands. Inter- osed charcoal was not ignited as easily as before, but a most intense ignition took place on bringing a metallic point connected with one pole of the series into contact with a piece of charcoal fastened to the other. It did not take place, however, so spee- dily as when glasses were used; but soon after the ignition was effected, it became even more powerful than before. A cylinder * See Adams’s Electricity, on Points. 1821.) Dr. Hare’s new Galvanic Apparatus, Theory, &c. 333 of platina nearly a quarter of an inch in diameter, tapering a little at the end, was fused and burned so as to sparkle to a con- siderable distance around, and fall in drops. A ball of brass of about half an inch diameter was seen to burn on its surface with a green flame. Tin foil, or tinsel, rolled up into large coils of about three-quarters of an inch thick, were rapidly destroyed, as was a wire of platina of No. 16. Platina wires in connexion with the poles were brought into contact with sulphuric acid ;— there was an appearance of lively ignition, but strongest on the. positive side. Excepting in its power of permeating charcoal, the galvanic fluid seemed to be extricated with as much force as wiew each coil was in a distinct glass. Apprehending that the partition in the trough did not sufficiently insulate the poles from each other, as they were but a few inches apart, moisture or moistened wood intervening, I had two troughs made, each to hold 4() pairs, and took care that there should be a dry space about four inches broad between them. They were first filled with pure river water, there being no saline nor acid matter to influence the plates, unless the, very minute quantity which might have remained on them from former immersions. Yet the sensation produced by them on the backs of my hands was painful, and a lively scintillation took place when the poies were approximated. Dutch gold leaf was not sensibly burned, though water was found decomposible by wires properly affixed. No a was produced on potash, the heat being madequate to use it. A mixture of nitre and sulphuric acid was next added to the water in the troughs, afterwards charcoal from the fire Was vividly ignited, and when attached to the positive pole a steel wire was interposed between it and the other pole, the most vivid ignition which I ever saw was induced. I should deem it _ imprudent to repeat the experiment without glasses, as my eyes, though unusually strong, were affected for 48 hours afterwards. If the intensity of the light did not produce an optical deception by its distressing influence upon the organs of vision, the char- coal assumed a pasty consistence, as if in a state approaching to fusion. That charcoal should be thus softened, without being destroyed by the oxygen of the atmosphere, will not appear strange, when the power of galvanism in reversing chemical afti- nities is remembered ; and were it otherwise, the air could have no access; first, because of the excessive rarefaction, and in the next place, as I suspect, on account of the volatilization of the carbon. forming about it a circumambient atmosphere. This last mentioned impression arose from observing that, when the _ experiment was performed in vacuo, there was a lively scintilla- tion, as if the carbon in an aeriform state acted as a supporter of combustion on the metal. : ee A wire of platina (No. 16) was fused into a globule on being connected with the positive pole, and brought into contact with 334 Dri Hare's new Galvanic: Apparatus, Theory} se. (May, apiece of pure hydrate of potash, situated) ona: silver tray in connexion with the other pole. The potash Arie reir Ae and ‘was deflagrated rapidly with a flame having the rosy hue of potassuretted hydrogen. es xl Heit ie The great apparatus of the Royal) Institution, in: projectile. power, was from six ‘to eight times more’ potent thanmine: It roduced a discharge between charcoal points; when removed about four inches apart, whereas mine will not» produce :a jet:at more than three-fourths of an inch. But that: was a series of 2000 pairs ; mine is only about a twenty-fifth part as large. A steel wire of about one-tenth of an inch in diameter affixed to the negative pole was passed up through the axis of an open necked inverted bell glass filled with water. A platina wire, No. 16, attached to a positive pole, being passed’ down to the steel wire, both were fused together, andecooling, could not:be _ separated’ by manual force. - Immediately after. this: mcorpora- tion of their extremities, the platina wire became incandescent for a space of some inches above the surface of the water. A piece of silvered’ paper, about two inches square, was folded up, the metallic surface outward, and festened into vices affixed to the poles. Into each vice a wire was screwed at the same time. The fluid generated by the apparatus: was: not per- ceptibly conveyed by the silvered paper, as it did not prevent the wires severally attached to the poles from decomposing water, or producing ignition by contact. . is In my memoir on my ta of galvanism, I suggested that the decomposition of water, which Wollaston effected by mecha- nical electricity, might not be the effect. of divellent: attraction like those excited by the poles of a voltaic pile, but of a mecha- nical concussion, as when wires are dispersed: by the discharge of an electrical battery. In support of that opimon, I will now . observe, that he could not prevent hydrogen and oxygen from being extricated at each wire, instead of hydrogen being given off'only at one, and oxygen at the other, as isinvariably the case when the voltaic pile is employed. That learned and inge- nious philosopher, in concluding his account of this celebrated experiment, says, “ but in fact the resemblance isnot complete, for in every way in which I have tried it, 1 observed each wire e out both oxygen and hydrogen gas, instead oftheir being ormed separately as by the electric pile.” Is it not reasonable to suppose that an electrical shock may dissipate any body into its elementary atoms, whether simple or compound, so that no two particles would be left together which can be separated by physical means. f cio% Looking over Singer’s Electricity, a recent and. most able modern publication, I find that in the explosion of brass wire by an electrical battery, the copper and zime actually separated. He-says, page 186, “ Brass wire is sometimes decomposed by the charge; the copper and zine of which it is. formed: being 1821.]| Dr. dares new Gateanic Apparatus, Theory, §c. 335 separated: fronveach other, and appearing in their distinct’ metallic colours.” In the next page of the same work, I find’ that the oxides of mercury and tiniarereduced by electrical dis- charges: ‘* Introduce,” says: the author, ‘some oxide of tin into a glass tubes! 'so that when the tube is laid horizontal, the oxide:may cover about half'aminch ofits lower internal surface. Place the tube: on the table ofthe universal discharger, and introduce the pointed wires into its opposite ends, thatthe por- tiom: of oxide may lay between them. Pass several strong charges in succession through the tube, replacing the oxide in its\situation;..should it be: dispersed. : If the charges are sufli- ciently, powerful, a part of: the tube: will'soon be stained with metallic tin: whichihas been revived by the action of transmitted electricity.” It cannot be alleged» that’ im ‘such decompositions the divellent:polar attractions are exercised like those which characterize:the: action of. wire: proceeding from the. poles of a voltaic apparatus. The particles: were’ dispersed’ from, instead of being: attracted to the wires, by which the influence was con- veyed among’ them. This being undeniable, it’ can hardly be advanced that: we are to have one mode of explaining the sepa- ration of the elements of brass by an electrical discharge, ano- ther of explaining the separation of the elements of water by the same-agent. One'rationale when oxygen is liberated from tin, and another when liberated: by like means from hydrogen. In thevexperiment in'which copper was precipitated by the same philosopher at the negative pole,.we are not imformed whether the oxygen and:acid im union with it'were attracted to the other; and the changes produced in litmus are mentioned not as simul- taneous, but successive. The violet‘and red rays of the spectrum have. an opposite chemical influence in some degree like that of voltaic poles, but this: has. not:led to the conclusion that the omen galvanism and light is the same. Besides admitting that the feeble: results obtained: by’ Wollaston and Van Marum with electrical: machines are perfectly analogous to those ob- tained by the galvanic pile, ere it can become an objection to my hypothesis, it ought first to be shown that the union between caloric and electricity, which I suppose: productive of galvanic phenomena, cannot be produced by that’ very process. If they combine to form the galvanic fluid) when extricated by ordinary galvanic action, they must have an affinity foreach other. As { have suggested in my memoir, when electricity enters the pores of a metal,.it may unite with its caloric. In Wollaston’s experiments, being constrained to enter the metal, it may com- bine with enough of its caloric to produce, when emitted, results slightly approaching to those of a fluid in which caloric exists in greater proportion. ) But once more I demand why, if mechanical electricity be too intense to produce galvanic phenomena, should it. be ren» 336 Dr. Hare’s new Galvanic Apparatus, Theory, &c. [May, dered more capable of producing them by) being still more concentrated. | ae If the one be generated more copiously, the other more intensely, the first will move in a large stream slowly, the last in a small stream rapidly, Yet, by narrowing the channel of the latter, Wollaston 1s supposed to render it more like the former ; that is, paets a resemblance by increasing the supposed source of dissimilarity. It has been imagined that the beneficial effect of his contri- vance arises from the production of a continued stream, instead of a succession of sparks ; but if a continued stream were the only desideratum, a point placed near the conductor of a power- ful machine would afford this requisite, as the whole product may in such cases be conveyed by a sewing needle in a stream perfectly continuous. As yet no adequate reasons have been given why, in operating with the pile, it is not:mecessary, as in the processes of Van Marum and. Wollaston, to.enclose the wires in glass or sealing wax, in order to make the electricity emanate from a point within a conducting fluid. The absence of this necessity is accounted for, according to my hypothesis, by the indisposition which the electric fluid has to quit the caloric in union with it, and the almost absolute incapacity which caloric has to pass through fluids unless by circulation. I conceive that in galvanic combinations, electro-caloric may circulate through the fluid from the positive to the negative surface, and through the metal from the negative to the positive: In the one case caloric subdues the disposition which electricity has to diffuse itself through fluids, and carries it into circulation. In the other, as metals are excellent conductors of caloric, the prodigious power which electricity has to pervade them agreeably to any attractions which it may. exercise, operates almost without restraint. This is fully exemplified in my galvanic deflagrator, where 80 pairs are suspended in two recipients, 40 successively in each, and yet decompose potash with the utmost rapidity, and produce an almost intolerable sensation * when excited only by fresh river water. I have already observed that. the reason why galvanic apparatus, composed of pairs consisting each of one copper and one zine plate, have not acted well with- out insulation} was because electro-caloric could retrocede in the negative as well as advance in the positive direction. . I will now add that, independently of the greater effect produced by the simultaneous immersion of my 80 coils, their power is improved by the proximity of the surfaces, which are only about * I do not say shock, as it is more like the permanent impression of a pointed wire ; and when an acid is used, of a hot one. + Thatis, with the same mass of conducting fluid, in contact with all the surfaces, instead of being divided into different portions, each restricted in its action to one copper and one zinc plate. ; 1821.4 Dr. Hare’s new Galvanic Apparatus, Theory, &c. °337 three-sixteenths of an inch asunder; so that the circulation may go on more rapidly. Pursuant to the doctrine, which supposes the same quantity of electricity, varying in intensity in the ratio of the number of pairs to the quantity of surface, to be the sole agent in galvanic ignition, the electrical fluid as evolved by Sir H. Davy’s great pile must have been nearly two thousand times more intense: than as evolved by a single pair, yet it gave sparks at ho greater distance than the thirtieth or fortieth of an inch. The intensity of the fluid must be at least as much greater in one instance than in another, as the sparks produced by it are longer. A fine electrical plate machine, of 32 inches diameter, will give sparks at 10 inches. Of course the intensity of the fluid which it emits must be 300 times greater than that emitted by 2000 pairs. The mtensity produced by a single pair must be 2000 times less than that produced by the great pile; and, of course, 600,000 times less than that produced by a good electrical plate of 32 inches. Yet 2 single pair, of about a square foot in area, will certainly deflagrate more wire than a like extent of coated sur- face charged by such a plate. According to Singer, it requires about 160 square inches of coated glass, to destroy watch pen- dulum wire ; a larger wire may be burned off by -a galvanic battery ofa foot square. But agreeably to the hypothesis in dispute, it compensates by quantity for the want of intensity. _ Hence the quantity of fluid in the pair is 600,000 times greater, while its intensity is 600,000 times less; and vice versa of the | coated surface. Is not this absurd ? What does intensity mean as applied to a fluid? Is it not expressed by the ratio of quantity” to space? If there be twice as much electricity within one cubic inch, as within another, is there not twice the intensity? But _ the one acts suddenly, it may be said; the other slowly. But ‘whence this difference? They may both have exactly the same surface to exist in. ‘The same zinc and copper plates‘may be used for coatings first, and a galvanic pair afterwards. Let it be said, as it may in truth, that the charge is, in the one case, attached to the glass superficies ; in the other, exists in‘the pores of the metal. But why does it avoid these pores in one case, and reside in them in the other? What else resides in the pores of the metal which may be forced out by percussion? Is it not caloric? Possibly, unless under constraint, or circumstances favourable to a union between this principle and electricity, the latter cannot enter the metallic pores beyond a certain degree of saturation; and hence an electrical charge does not reside in the metallic coatings of a Leyden phial, though it fuses the wire. which forms a circuit between them. _ tis admitted that the action of the galvanic fluid is upon, or between, atoms; while mechanical electricity, when uncoerced, acts only upon masses. This difference has not been explained unless by my hypothesis, in which caloric, of which the influence New Series, vou. I. Y : 338 Dr. Hare’s new Galvanic Apparatus, Theory, &c. . [May, is only exerted between atoms, is supposed to be a, principal agent in galvanism. Nor has any other reason been given that water, which dissipates pure electricity, should cause the galva- nic fluid to accumulate. From the prodigious effect which moist air, or a moist surface, has in paralysing the most. efficient machines, I am led to suppose, that the conducting power of moisture so situated is greater than that of water under its sur- face. -The power of this fluid to conduct mechanical electricity is unfairly contrasted with that of a metal, when the former is. enclosed in a glass tube, the latter bare. According to Singer, the electrical accumulation is as great. when water is used as when more powerful menstrua are ~ employed; but the power of ignition is wanting until these are resorted to. De Luc showed, by his ingenious dissections of the pile, that electricity might bs produced without, or with chemical power. The rationale of these differences never has been given, unless by my theory, which supposes caloric to be present in the one case, but not in the other. The electric column was the fruit of De Luc’s sagacious inquiries, and afforded a beautiful and incontrovertible support to the objec- tions he made to the idea, that the galvanic fluid is pure electri- city, when extricated by the voitaic pile in its usual form. It showed that a pile really producing pure electricity is devoid of the chemical power of galvanism. ° Weare informed by Sir H. Davy that, when charcoal points. in connection with the poles of the magnificent apparatus with which he operated, were first brought nearly into contact, and - then withdrawn four inches apart, there was a heated arch formed between them, in which such non-conducting substances. as quartz were fused. I believe it impossible to fuse electrics. by mechanical electricity. If opposing its passage, they may be broken, and if conductors near them be ignited, they may be acted on by those ignited conductors as if otherwise heated; but. I will venture to predict, that the slightest glass fibre will not enter into fusion by being placed’in a current from the largest. machine, or electrical battery. | I am induced to believe that we must consider light, as well as heat, an ingredient in the galvanic fluid ; and think it pos- sible, that, being necessary to vitality in animals, as well as. sepstaples the electric fluid may be the vehicle of its distri-. ution. I will take this opportunity of stating, that the heat evolved by one galvanic pair has been found, by the experiments which Linstituted, to increase in quantity, but to diminish in intensity, as the size of the surfaces may be enlarged. A pair containing about 50 square feet of each metal will not fuse platina, nor deflagrate iron, however small may be the wire employed; for the heat produced in metallic wires is not improved by a reduc- tion in their size beyond a certain point. Yet the metals above- 1821.] Dr. Hare’s new Galvanic Apparatus, Theory, §c. 339 mentioned are easily fused or deflagrated by smaller pairs, which would have no perceptible influence on masses that might be sensibly ignited by larger pairs. These characteristics were fully demonstrated, not only by my own apparatus, but by those constructed by Messrs. Wetherill and Peale, and which were larger, but less capable of exciting intense ignition. Mr. Peale’s apparatus contained nearly 70 square feet, Mr. Wethe- rill’s nearly 100, in the form of concentric coils, yet neither could produce a heat above redness on the smallest wires. At my suggestion, Mr. Peale séparated the two surfaces in his coils into four alternating, constituting two galvanic pairs into one reci- ient. -[ron wire was then easily burned, and platina fused by it. These facts, together with the incapacity of the calorific fluid extricated by the calorimeter to permeate charcoal, next to metals, the best electrical conductor, must sanction the position I assigned to it as being in the opposite extreme from the columns of De Luc and Zamboni. For, as in these, the pheno- mena are such as are characteristic of pure electricity, so in one very large galvanic pair, they almost exclusively demonstrate the agency of pure caloric. | : P. 8. Since writing the above, I have endeavoured in every mode which I could devise to ignite charcoal by electricity. Exposed to the discharge of a powerful battery in pieces taper- ing to a point, in a glass tube, in thin strips, and in powder, by means of the glass usually employed for inflaming ether, it was either uninfluenced, or merely dispersed, without the smallest symptom of ignition, or even of increased warmth. Yet fulmi- nating mercury was flashed by the discharge, under the same circumstances as those in which the p>wdered charcoal had been | subjected to it. The result, therefore, was such as might be expected from a “ mechanical concussion.” Pointed wires were covered with spermaceti, and exposed to a current from a fine plate machine of 32 inches diameter; yet no sign of fusion - appeared. Nor was a differential thermometer filled with ether, according to Dr. Howard’s sagacious plan, affected sensibly, though the warmth of a finger applied to the bulb caused the fluid in the stem to move nearly a foot. I mentioned in the memoir, p. 332, that when a knob of lead suspended by a filament to one of the poles of my deflagrator was made to touch the other pole of the same instrument, the knob was fused, the filament uninjured. I find the reverse is the case, when a knob suspénded by a filament is made the medium of discharging an electrical battery. The filament is destroyed, the knob remains unchanged. It must be evident, therefore, that galvanic and electrical ignition are extremely discordant in their characteristics. It is also mentioned in the memoir that a piece of silvere x2 340 Mr. Herapath onthe Causes, Laws, and principal. [Mavy, paper, two inches square, proved inadequate to discharge my galvanic apparatus of coils, yet at a distance 70 times greater, a strip of the same paper, one-third of an inch wide, and 20 inches long, caused an:instantaneous discharge: of the electrical battery. : Articie II. | A Mathematical Inquiry into the Causes, Laws, and principal dotm He. Phenomena:of Heat, Gases, Gravitation, &c. B rapath, Esq. (Ina Letter to D. Gilbert, Esq. MP. VPRS.&c.) (Continued from p. 293.) Or rue Laws or Gaseous Boptes. — - Definitions. _ Def. 1.—The homogeneity of a gas.is the perfect equality ofits atoms, or particles, throughout, in quantity of matter. «| Ltis: of no consequence whether the atoms are similar in figure or not ; their figures might be very different, provided, however, the ‘quantity of solid matter in each js the same. Def. 2.—Density is the quantity of matter in a given space, when the atoms, or particles, whatever be their reiative magni- tudes, are uniformly disposed in the medium. ets i Cor. 1.—The. mean density of any body is, therefore, propor- tional to the whole quantity of matter, divided by the whole bulk, or magnitude of the body. i | | Cor, 2.—In.a homogeneous body,, the density is equal to the mass of an. atom drawn into the number contained. in a given space. rc: Dey. 3.—Numeratom is a term I have employed to express the number of atoms, or particles, distributed throughouta given _ space, without respect to the density or homogeneity. of the body. | Cor.—Hence the numeratom of a homogeneous body. is. pro- portional to the density directly, and the mass of a particle, or ‘atom, inversely. | This conclusion might also have been drawn from Cor, 2 of - the preceding definition. t Def. 4.—The elasticity of a gas, is the force with which. it endeavours to expand itself, or with which it resists compres- sion; and is estimated by the amount of. its action against _ similar and equal portions of the containing bodies, ~ GenERAL ConsIDERATIONS ON Force AND THE ConstTiTU- TION oF GasxEous Bopigs. ' Force is the cause of ppt Em or is that power, by which. the change is produced. If, therefore, a body be perfectly free 1821.] Phenomena of Heat, Gases, Gravitation, &e. 34h to-yield to any change of state, and none take place, it follows, that the body is not acted on by any force; orif it be, it must be by an accumulation of opposing forces, which, in the aggre- gate, destroy one another. Mathematicians usually estimate force by the: effect’ it produces, or would produce, in a given time, and consider the intensity of the force as proportional to the effect. Thus, if one of two forces produce twice the effect ofthe other, it is considered to be doubly as powerful ; if three times the effect, trebly; and so on. But this is rather estimat- ing the effects than ‘the forces; since it is possible for the same primitive foree, by successive actions, to produce very unequal effects in equal times. : Forces have likewise been distinguished into two kinds, ,pres- sive and impulsive, or those which ‘act by pressure, and those which act by impulsion. The former generate changes in bodies by a continued unceasing action, from the beginning to the end ofithe stroke, or fit, of action; and, consequently, always con- sume time. The latter act either by an instantaneous impulse, or by a succession of those impulses ; but each impulse, indivi- dually considered, occupies not the smallest portion of time. It is an action that in one moment might be said not to have come into existence ; and in thenext to have ended. Thisis the kind | of force we have now to consider. ; If we take single impulses, it is plain that the forces: and the changes they produce are proportional, under the same circum- stances of.action. But if a succession of impulses takes place, the effects are no longer proportional to the forces, but to the collected actions of the forces in equaltimes. When, therefore, the forces are equal, the effects are proportional to the numbers oftheir respective repetitions; ‘and when those forces are unequal, but uniformly intense in their actions, the effects are in ° the compound ratio of those numbers and the forces. It is. hence manifestly possible for a weak force, by a greater number of successive actions, to produce effects equal to those of a stronger by a less number of actions; and if the impulses of the two'forces be at regular intervals, and yet the intervals of the slower be not sensible to observation, the effects will always have’ the same ratio, whatever be the length of time. in which they are compared. These impulses may also be opposed to a pressive force, and __ effect precisely the same things. For let us suppose a iiard ‘body to be acted on from a state of quiescence by a continued » force, such, for instance, as what we commonly: conceive gravity to be, urging it in any direction’; then, after it’ has been impelled . forward for any length of time by this force, and has acquired a certain momentum, let it be met by another hard body, moving uniformly with an equal momentum in the opposite direction ; and by our laws of collision, it will receive such a change in its motion by the contact as will give it an equal and opposite: _ -their collisions, or the number of the bodies. ea 342 Mr. Herapath on the Causes, Laws, and principal [May momentum in the path it has already described. It will, there- fore, being acted on still by the soliciting force, retrace this path, until, having ascended to the point whence it set out, it has lost all its velocity, and begins to descend again as before. As soon as it has arrived again to the place where it before was met by the other body, let it receive a second equal shock, and again it will begin to ascend; and so on as long as we please. Thus it.might be continually kept oscillating between these two pants by impulses propeny regulated. And if the distance etween the points be diminished, the number of oscillations will be increased, and the intervals between the shocks dimi- nished, and the body consequently approach nearer to a state of apparent rest. his is how things will happen when the affected body comes in contact with only one other body, and receives the strokes in the direction of the track of its centre of gravity. But the same would evidently take place, if, stead of one body striking it in this identical manner, it were struck by several in different parts of its surface, either all at once, or in any order; the aggregate direction and intensity of whose strokes, however, should. be similar to those of the single body under similar circumstances. Then might the body acted on by the force remain in a state of rest, if not absolute, at least so nearly so, as to differ from it insensibly. Now the tendency of this .body to move in the direction in which it is solicited is precisely the same thing as mathematicians understand by the force, which they call pres- sure; and, therefore, the opposition of the other smaller bodies is also equivalent; and, as to effect, the same as this force of pressure. And because the value of this pressure might be increased or diminished ; by increasing or diminishing the soli- citing force, or the pressing body ; so also might the value of the resisting force of the smaller bodies be increased or diminished, by increasing or diminishing their momentum, the number of From these considerations it follows, that if a number of small bodies be inclosed in any hollow body, and be continually impinging on one another, and on the sides of.the enclosing body; and if the motions of the bodies be conserved by an equi- valent action in the sides of the containing body, then will these small bodies compose a medium, whose elastic force will be like that of our air and other gaseous bodies ; for.if the bodies be exceedingly small, the medium might, like any aeriform body, be compressed into a very small space; and yet, if it had no other tendency than what would arise from the internal collision of its atoms, it would, if left to itself, extend to the occupation of a space of almost indefinite greatness. And its temperature remaining the same, its elasticity would also be greater when occupying a less, and less when occupying a greater space; for ina condensed state the number of atoms striking against a \ 1821.) Phenomena of Heat, Gases, Gravitation, &c:- 3.48 given portion of the containing vessel must be augmented ; and the space in which the atoms have to move being less, their returns, or periods, must be shorter; and the number of them, in a given time, consequently greater, on both of which accounts the elasticity is greater, the greater the condensation. Besides, when other things are the same, the elastic force augments with an augmentation of temperature, and diminishes witha diminu- tion ; for an increase of temperature, according to our theory, must necessarily be attended with an increase of velocity; and, therefore, with an increase in the number of collisions. But these things will be more accurately treated of presently. - Whether all pressive forces be not the same as this gaseous action, is a question we do not at present intend to consider. It might come under our cognizance hereafter, when we shall have had more opportunities of collating our principles with experi- ments. In the mean time it is sufficient to anticipate that our inquiries, whatever be the possibility of the existence of another kind of pressive force, lead us to conclude that nature operates | by no other. | an [t might be asked by what means is it, if the parts of the gases are absolutely hard, that they are reflected back into the mediunr from the sides of the containing vessel? This question is easily answered, if we allow heat to consist in an intestine motion of the parts of the bodies; for then the parts of a-solid, of equal temperature with a gas, must have the same quantity, though they have not the same freedom of motion as the parts of a gas have ; and hence the parts of the gas will have the same refiec- tion from the sides of the vessel that they have from one another. ‘Prop. VI. The figure of the vessel, in which a gas is contained, has no influence on the elastic force of the gas, such a constitution of things being granted as we have supposed. — For since the particles of the gas receive their reflection from the superficial particles of the containing body; and since these particles have not only their intestine motion, but likewise their figure and arrangement, independent of the superficial figure of the containing body, it follows, that the direction of their action on the particles of the gas is also independent of the figure of the body in which they are enclosed. But other things being alike, this action is equal to the contrary action of the particles of the gas, which constitutes its elastic force ; therefore, its elastic force is not affected by the figure of the body in which itis contained. Cor.—Hence we gather that in any bodies of equal capacity and of the same temperature, the same, or an equal portion of the same gas, would be equally elastic ; for the motion of the particles being independent of the figure of the containing body must depend entirely upon the temperature of that body; and ” » 344. Mr. Herapath on the Causes, Laws, and principal [Mav, this being the same, the motion is the same.- But.the motion, — quantity. of gas, and capacity, being the same, the elasticity must. be the same. : i Scholium. This theorem and its cor. agree with the opinion, of philoso- phers respecting the elasticity of. gaseous Bodies though I am not aware that they have ever been made the subject of direct experiment. Indeed it seems to have been taken for granted that wherever the temperatures, spaces occupied, gases, and quantities of gas, were the same, the elasticities were the same; but it. would be worth while to be more certain of it. An expe- riment to settle this point, taking every circumstance into consi- deration, would, perhaps, require as much care and skill as almost any of those that have been made on gases. _ Prov Vit If a given portion of a fluid gas, composed. of particles mutually impinging on one another and the sides of the contain- ing body, in the manner that has been described, has its temper- ature-the same; and if the particles, be indefinitely small, its elastic force, under different compressions, is reciprocally propor- tional to the space it occupies. . . | : ' Let. us suppose that equal portions of the same gas be enclosed in two vessels of unequal capacity. Then, by the last Prop. it is immaterial whether these vessels be of the same or of different figures; the difference of figures would have no influence upon the ratio of the elasticities ; but, for. the sake of simplicity, we will. suppose the two figures similar. Now because the only change that is supposed to take place is in the space which the gas occupies, the motions and collisions of a particle in the one will be similar to those of a corresponding particle in. the other;. and the temperature, that is, in this case, the velocity being the same in each, the numbers of revolutions that two corresponding particles in the two media make in a given time must. be inversely proportional to the paths the particles describe; thatis, these paths being alike and described with equal velocities in the inverse subtriplicate ratio of the spaces oceupied by the equal portions of gases. But because the elasticity of a gas is proportional to the action of its particles against a given portion of the surface of the containing body, the ratio of the elastic forces, arising from the repeated actions of equal numbers of cor- responding particles in the two media, will likewise, their velocities being the same in both media, be inversely as: the subtriplicate of the spaces occupied. And if we conceive the two gases. to be divided into strata, parallel to the sides of the bodies on which the elastic forces are measured, and of one, two, or any number of particles thick, it is manifest, since the motions. of the particles are alike in each medium, that if the elasticity. 1821.) Phenomena of Heat, Gases, Gravitation, &c. 345 in one medium arises from the action of the particles of the first. stratum alone, soit does also in the other medium; and if it arises from the action of the particles of the two first, three first, or” first strata‘in one medium, the same holds true with the elasticity in the other medium. But the number of particles of any one stratum that strike against a given portion of the con-.. taming surface of one medium, is to the number of particles of the corresponding stratum that strike against an equal and simi- lar portion of the other medium, in the duplisubtriplicate ratio of. the numeratems directly ; that is, in the duplisubtriplicate ratio of the spaces occupied by equal portions of the gases inversely. Therefore as the whole elastic forces of these corresponding strata are ina ratio compounded of the ratios of the numbers of*: particles that strike against: equal portions of the sides of the containing bodves, and of the numbers of returns which they’ make to the sides in a given time, that ratio must be equal to- one compounded of the inverse duplisubtriplicate and of the inverse subtriplicate ratios of the spaces occupied by the two gases; it must, therefore, be equal to the simple inverse ratio of — the spaces occupied. And since the same. number of strata affects the elasticity of the one gas as of the other; and since the inverse ratio of the spaces is the ratio of the elastic force of any two corresponding strata, it is consequently the ratio of the — united elastic forcés of all: the strata that affect the elasticity ; and is, therefore, the ratio of the elastic forces of the two gases. Cor.—Because the numeratoms are reciprocally proportional to the spaces occupied, it follows that the elasticities are, under equal temperatures, directly as the numeratoms. , _. Scholium. We have in the two preceding theorems and their corollaries supposed the atoms, or particles, to be perfectly hard; but the same consequences would follow if they were either perfectly or imperfectly elastic, and the containing vessel either elastic or hard. For the temperature being invariable, the intensity of the collisions, and consequently of the reflections, would remaim the same in a rare as ina denser medium. The law, therefore, that the elasticities and compressions are proportional, under: equal temperatures, is true not only in permanent airs or gases, butiin all kinds of vapours, which is conformable to experience. Prop. VIII. The same things remaining, the elasticity of a gas under a variable temperature and compression, is proportional to its numeratom and the square of its temperature conjointly ; or the elasticity varies as the square of the temperature directly, and the simple of the space inversely. ; -If-we first suppose in two portions of the same gas the nume- ratoms to be equal, the elasticities of those portions will have the 346 Mr. Herapath on the Causes, Laws,yand principal [May, same ratio as the elasticities arising from the actions of corre- sponding particles in the two media; for the change of tempera- ture does not alter the manner in which the corresponding articles act in the media,’ but. only the intensity of action. his being the case, the elasticities due to the actions of corre-» sponding particles are to one another as their momenta and the number of their revolutions or returns in a given time; that is, as their temperatures and velocities. But the masses of the’ corresponding particles being the same, the velocities are as the temperatures ; therefore, the elasticities due to corresponding particles, and consequently the elasticities of the media, are as the squares of the temperatures. And by the cor. to the preced- ing prop. the temperatures being the same, the elasticities are as the numeratoms. Whence, if neither the temperatures, nor the | numeratoms are the same, the elasticities are in a ratio com- pounded of the ratio of the numeratoms, and that of the squares of the temperatures, or, whichis the same, in a ratio compounded of the inverse ratio of the volumes and the duplicate direct or the temperatures. eee as Cor. 1.—Hence the elasticities are also in a ratio which is equal to that compounded of the simple ratio of the numeratoms, and the duplicate of the velocities. Cor. 2.—And hence also the elasticities are in a ratio com=. pounded of these three simple ratios; namely, the ratio of the numeratoms, the ratio of the temperatures, and the ratio of the velocities. Prop. IX. The spaces occupied by equal portions of the same gas, under equal elasticities, are directly proportional to the squares of the temperatures. : : For by the preceding proposition, the elasticity varies as the numeratom and the square of the temperature conjointly ; there- fore, the elasticity being constant, the numeratom is inversely — as the square of the temperatures. But the quantity of gas’ - being the same, the space occupied is reciprocally as the nume- ratom; consequently the space, or volume, is directly as the square of the temperature. | Cor. 1.—Because this is true of any gas, it follows that equal volumes of any gases whatever, under equal pressures and tem- peratures, will be equally augmented by equal augmentations of temperature. Cor. 2.—Or more generally, if the elasticities of any two gases have an invariable ratio, and if their temperatures also have an invariable ratio, their volumes will have an invariable ratio. Cor, 3.—It has been found by MM. Dalton and Gay-Lussac, and lately confirmed by the further experiments of MM. Dulong and. Petit, that the volume of a given portion of gas at the tem- perature of water freezing is to its volume under an equal pres- 1821.] Phenomena of Heat, Gases, Gravitation, §¢. 347 sure at the temperature of water boilimg as 8 to 11. Therefore, granting the truth of our principles, the temperature of water freezing is to that of water boiling in the subduplicate ratio of 8 to 11; that is, nearly in the ratio of 6 to 7; or, more nearly, in that of 100 to 117, or that’ of 579 to 679. Cor. 4.—Because the temperatures are in the same gas as the velocities, the spaces occupied at equal elasticities are as the square of the velocities. Cor. 5.—It has been demonstrated by the experiments of phi- losophers, that the volumes of mercury and air, under the same pressure, go on part passu within certain limits; namely, from about — 36 of centigrade toneariy 150. There- fore, let A B be a common mercurial thermome- ter, of which F is the freezing and B the boiling © point of water; and let the tube, or a line by the side of it, be continued to the point C, so that BC:FC::11:8; and let C B be made the axis of a parabola, whose vertex is C; then will any semiordinate M P, between the limits / {— 36).and L (nearly 150), drawn from the sur- face M of the mercury, represent the tempera- ture of the body in which the thermometer is plunged; and C M the volume, due to the ex- pansion of air under the same temperature and a uniform pressure. , ‘From these circumstances it appears, that the measures which have been taken by MM. Dulong and:Petit, in their late memoir on the communication of heat, are not proportional to the tem- peratures, as they imagine, but to the squares of the temper- atures. | | Cor. 6.—Since, if the temperatures are the same, the volumes are inversely proportional to the elasticities, it follows that the volumes being the same, the squares of the temperatures are as the elasticities. Hence, therefore, the same results would be obtained by measuring the temperatures by the elasticities, under an invariable volume, as by the volumes under an invariable compression, which is conformable to what MM. Dulong and Petit say they have found from experiment. This same inference I had drawn from theory several years before Dulong and Petit had made, or at least had published their experiments; and upon _ this principle I had contrived a thermometer by means of hydro gen and mercury, the description of which I have by me. Scholium. Inthe preceding theorems and their corollaries, we have not con- sidered whether the media be homogeneous or not, or whether their particles be similar or dissimilar. The theorems are totally inde- pendent of all considerations of homogeneity or similarity, and 348 Mr. Herapath onthe Causes, Laws, and principal. [Mavy, © are, therefore, equally applicable to all gases, simple, or com- pound, supposing, however, their particles to be indefinitely small, or their diameters to have no sensible proportion to the: lines they describe. One of the longest known laws of gaseous bodies is, that of ’ the volume being reciprocally proportional to the elasticity. This lawis demonstrated in mot 7, and is one that I have been ‘careful to establish by a clear and explicit proof, as well’ on account of its own importance, as of its being the foundation of most of my other deductions on the properties of gaseous bodies. I have, however, shown, in the scholium to prop. 7, that the same law would result from the supposition of the particles being either perfectly or imperfectly elastic. But though this is true in the present instance, it is not so universally. For if we sup- ie a medium to be composed of elastic particles, and to be ept in a gaseous state by the actions of its: Datars on one another, and on the particles of the containing body ; and if we also suppose the temperature to be equal to the momenta which these gaseous particles impress on the particles of the other bodies, then we find that, in order to preserve the temper- ature of the containing body, the gaseous particles must have such motions as will repel the particles of the containing body, with momenta equal to the momenta which they had previous to the contact. But to do this, the particles of the gas, if they ‘and the particles of the containing body are unequal, will have different motions before and after the collision, which is evidently absurd. And if the gas should be transferred into a different body, whose particles are larger or smaller than the particles of the other body, the temperature and elasticity of the gas will be changed, though both the capacity and temperature of the two containing bodies should be the same. Besides, the temperatures of the gas and of the containing bodies would never be the same, if their particles were unequal. Nor could a gas, constituted of elastic particles, follow the laws of either of the other propositions. {f any method were known of experimentally determining the ratio of the temperatures of two bodies, we might easily devise ways enough of putting our theory to the test of observation; but since tlis 1s not the case, independent of theorems drawn from our principles, we are obliged to search for such consequences as are not under the controul of the ratio, or of the quantity of temperature. The inference drawn in the first cor. to prop. 9 is precisely of this kind, and presents us with a law that is easily examined by experiment. Indeed this-law was discovered several years ago by MM. Dalton and Gay-Lussac, and has been established by many experiments. It is one of the most important laws, relative to the expansion and contraction of gaseous bodies, that has yet been discovered; and affords not’: \ : 1821.] Phenomena of Heat, Gases, Gravitation, &c. — 349 only a striking instance of the coincidence of our theory of the constitution of gases with phenomena, but also a fine corrobora- tion of our theory of collision. In cor. 2, I have generalized this law, by which means we have an opportunity of comparing the theory with phenomena on amore extensive and varied scale. For if we suppress the ratio of the temperatures, by making it the ratio of equality, this cor. will, in a variety of ways, become comparable with obser- vation. By taking portions of any two gases, and measuring their elasticities and volumes at any common temperature, we ought by this cor. to find, that if we raise or diminish the tem- peratures equally, and make the ratios of the first and'second volumes equal, the ratios of the first and second elasticities ought to be equal. Again, ifthe two temperatures be equal, and we any how change the temperature, elasticity, and volume of one of the gases ; and if we make the second elasticities and volumes to hold respectively the same ratios as the first ; then ought the second temperature of the one gas to be equal to the second ‘temperature of the other. ; Prop. X. _ If the ratio of the elasticities of any two gases be that of eto 1, the ratio of their volumes that of v to 1, and of their tempera- tures that of ¢to 1; and if the elasticities, volumes, and tem- _ peratures of these'gases be any how varied, so that the ratios’of the second elasticities, volumes, and temperatures, be respectively ‘those of e; to 1, v, to 1, and ¢, to 1 then will the ratio of 2, to 1 be equal to thatiof-e t,°v to (?-v,. - + Forlet us call V, V the first volumes ; E, E the first elastici- ties ; and 7’, T the first temperatures of the.gases; and let V|, V, m like manner denote their second volumes : E,, E, their second elasticities; and 17',, T, their second temperatures. Then ‘by hypothesis, we have | ute ; | OW ct Vi sts Lead Lert V? ce tol EE: :e 3.1 By 3sBes ei: Weed WETS eee | Laid yw teask But by prop. 8, EB, :E 3 T2V, 27% Vis and Be SEG Bo Wat dae Yi sRe E 3E :ne oe 2 Therefore compounding these ratios, we shall get E, : E, orve, & bse eds Sly pee oD? PAV OV: and consequently’ e,': ‘1: :: e¢,*.v: 2°.u,, Cor. 1.—From this theorem it-appears, that if the ratio of the first temperatures be a ratio of equality ; and if the same be the ‘case with the:ratio of the second temperatures, no matter what “be the ratio of the first and second temperatures ; and if the 350 Mr. Herapathon the Causes, Laws, and principal [May, same hold good with the ratios of the first and second volumes, then will the ratio of the first elasticities’ be equal to that of the ‘second. That is, the volumes and temperatures of two gases always preserving ratios of equality, however much these volumes and temperatures may vary, the elasticities will maintain a given ratio. ‘This is precisely what follows from cor. 2 to the preced- ing prop. . Cor. 2.—Supposing the same things to hold good, respecting “ee the temperatures, the theorem becomes v, : 1 :: { i «| ; that vl is, the ratio of the second volumes is equal to the ratio com- pounded of these three ratios; namely, the direct ratio of the first elasticities, the inverse of the second, and the direct of the first volumes. N.B. The same things will also hold good in both these corollaries, if the two ratios of temperatures, instead of being ratios of equality, are equal. 7 Cor. 3.—In the construction of Mr. Leslie’s differential ther- mometer, it is supposed, when the two balls are of equal temper- atures, that the elasticities and volumes are also equal. Therefore in this case, e, t, and v, are each unity, and ¢, : 1:1 / o ; rf 4 which, because the alteration in volume is but trifling, is nearly equal to ./e,: 1. Hence, if we know the ratios of the second volumes and elasticities, we also know the ratio of the second temperatures ; or if we know only the ratio of the second elasti- cities, this ratio of the second temperatures is nearly ascertained ; and, therefore, one of the second temperatures being known, the | other, and the difference of the two, become known. But the ratio of the volumes is easily ascertained, by admeasurements previous to the making of the instrument ; and the difference in the elastic forces is determined by the difference in the altitudes of the fluid in the two legs, from which and by keeping one of the legs at a certain temperature, and by having measured the elastic force of the gas at that temperature, before the finishing of the instrument, we shall be enabled to obtain the difference and ratio of the two elasticities, and thence the temperature of the gas in the other leg. waren I have for want of time but. just mentioned this ingenious and useful little instrument, whose theory is contained in the preced- ing prop. but he that wishes to be fully acquainted with its merits and the variety of purposes to which it is applicable, may consult Mr. Leslie’s taser on Heat and Moisture, published. a few years since. : Scholtum. It has in cor. 5 to prop. 8 been remarked that the augmen- tations of volume in mercury and any gas have so nearly a given 1821.] Phenomena of Heat, Gases, Gravitation, §c. 351 proportion, between certain temperatures, that scarcely any difference can be observed. With this fact, therefore, it will be. no difficult matter to examine the preceding theorem by direct experiment, in a more general way than we have yet supposed ; for all the other ratios might be easily determined by methods already known, and the temperatures might be measured between the limits alluded to by a common mercurial thermometer, either in the way that is pointed out in cor. 5, prop. 8, or by dividing the thermometer into equal parts, letting the freezing point stand at 80° and the boiling at 110°; in which case the divisions would indicate the squares of the temperatures. Thus all the ratios. might be obtained by experiment independently of each other ; consequently, by combining any of them according to the theory, we shall be able to see whether the result agrees with that given by experiment. | Having now demonstrated, as they flow from our principles, some of the chief properties of gaseous bodies, after the manner of mathematicians, and in a way that I hope will satisfy the Royal Society, both of the legitimacy and simplicity of those principles, » I shall throw some other things, which it appears necessary to add, into a general scholium. | (To be continued.) ArTICLE IV. | _ A Memoir onthe Physiology of the Egg, read before the Linneaw Society of London, on March 21, 1809; an Abstract of which is published in the Society’s Transactions. By John Ayrton Paris, MD. &c. &c. {Having accidentally seen Dr. Paris’s paper on the Physio- logy of the Egg, which had been printed, about 10 years: — since, for private circulation, it appeared to me to contain so- much curious matter that I was desirous of inserting it in the: Annals, Dr. Paris has not only kindly consented to my request, but has added several new and interesting particulars to his ori- ginal memoir.—Ldit.] ‘¢ At certe Natura, si fieri potuisset, maxime optasset suum opificium esse immortale ; quod cum per materiam non liceret, subsidium quod potuit ipsi ad immortalita- tem est fabricata, nam mirabilem quandam rationem invenit, quomodo in demor tui animalis locum, novum aliud sufliciat.”"—Gaien de Usu Partium. . Tue extensive range which the Oviparit form in the scale of animated existence renders the organization and developement of the egg a subject of great and general interest to the natural- ist; while the hope of ascending to the source of vitality, by 352 Dr. Paris on the Physiology of the Egg. (May, . contemplating life at a period when the number and complica- tion of its functions are the least, becomes an irresistible induce- ment to the physiologist to pursue the investigation : hence we find that the philosophers of every age and nation have devoted much time and labour to this inquiry. Unfortunately, however, for science, the influence of chemical powers in the scheme of animal life has only of late been investigated in reference to the problem ; but many beneficial results have already attended this new train of research, and the most exhausted topics. of natural history have assumed novel and very unexpected aspects. The author, therefore, of the present memoir may reasonably hope to escape the censure which must otherwise have awaited. the adventurer who could presume to beat the field that has before been so ably and diligently explored by the united labours of Fabricius ab Aqua pendente, Harvey, Malpighi, Spallanzani, Hunter, and other physiologists. A powerful phalanx of philoso- phers maintain, with much plausibility, that the egg* is the universal womb of nature, and that oviparous differ only from viviparous animals by the latter betegee | their ovular bondage + before they escape from the parent. Concerning the truth of this opinion, which is comprehended in the popular aphorism, “ Omnia ex Ovo,” or with regard to the success with which the eloquent Count de Buffon has levelled his shafts against the etary of this theory, I shall. leave abler disputants to decide. e observations which I am prepared to submit to your notice do not involve the truth of either theory, but are connected only with those animals that are oviparous, in the common accepta- tion of the term; that is, who deposit a germ to be developed by causes totally independent of parental influence. | ‘Among the countless multitudes and varieties of animals, a — very small proportion only are:viviparous, or produce living off- spring: thus the immense tribes of birds, fishes, amphibious animals, and insects, with comparatively few exceptions, { pro- * Eoc.—The word Ovum seems to be derived fromthe Greek word Ofdy, solita- rium, because it produces only one offspring; thus Fabricius ‘ quia singularia pariat, non enim veluti czteri uteri intra se plures gignunt foetus.” That each egg should “include but one embryon seems to be a general law of nature, but not without its excep- tions ; a singular species of egg was ‘found by Mr. ‘Folks, President of the Royal ‘Society, in the mud of a riyulet, which equalled in size a pin’s head. By breaking the ~shell he dislodged nine worms, all of which were contained within one involucrum. + The system of the ovarists has been adopted by Harvey, ‘Steno, Malpighi, Valis- nieri, Duhamel, Nuck, Littre, Swammerdam, Haller, Spallanzani, Bonnet, &c. It _mnust not be forgotten that there are some animals that cannot be called oviparous in whatever signification the term may be received; the hydra, for instance, multiplies its _ Species by. sending off shoots from its own body, and may, therefore, be said to be gem- miparous. . ; t Some fish are viviparous, e-g. Murena Anguilla, or eel, Blennius Viviparus, &c. , Among the amphibia we may notice the viper, which brings forth its yonns ts and ‘hence probably derives its name, guod vivum pariat. Spallanzani considers also the \ production of’ frogs as being rather of a viviparous than oviparous nature ; this rudi- _tment, however, of the future animal certainly partakes as much of the nature of an egg as of a foetus, and may probably be considered-as a connecting link ‘between the'two great classes. Insects likewise present us with exceptions, and several whimsical varie~ , : 1821.]) Dr, ‘Paris\on the Phiysiolowy of the Egg. 353 pagate their species by the intervention of the egg, nor is sucha mode of generation either accidental in its occurrence, or unim- portant in its operation; had the winged imhabitants of the air been viviparous, the burden of gestation would have impeded the action of their wings, and have so far inereased their gravity as to have rendered them incapable of the exertion of flight: the rigid and unpliant coverings: of| cruséaceous animals would have opposed the expansion necessary for the developement of a foetus; and itis evident from the structure and habits of the tribe of serpents, that if they had-been viviparous, their offspring - must have suffered materially from the tortuous flexions, and friction necessarily attendant!‘ upon their progressive motions ; and, lastly, the mu/feparous* nature of insects and fishes at once convinces how improvident it would have been to engender them by any other mode than that which nature employs. The eggs of the ovipari admit of an evident division into two classes, which J] shall denominate, 1. Phe Perfect ; and 2. The Imperfect. 'The former, which are deposited by the aves, and some genera of amphibia, are completely covered by a hard shell, or membrane, and receive no additions after their exclusion ; while the latter are deposited by most pisces, and) in general constitute a soft mass (flavago), not being protected by any external inyolucre. ‘The observations contained in this memoir relate more particularly to the egg of birds : their history, how- _ ever, comprises whatever is interesting orimportant in the germs ofanferioPanimals. , In order that‘I may be better able to form a systematic rela- - tion of those new facts and opinions which I wish to submit te ties; the aphides lay eggs at the end of autumn, when the young produced from them in.thespring are viviparous during the.whole summer! The. cocci hatch their eggs before their exclusion, and the young force their way through the abdomen of their mother. The onisct carry their eggs in a particular receptable, from which, in process. of time, a the young, make their escape. The hippobosca, brings forth neither eggs, nor larvae, but these already gone into the pupa state! The lacerta salamandra brings forth young, complete in every part, but still enclosed in.an egg. * Reaumur ascertained that a single queen bee had laid in the months of March and April 12,000 eggs; and Lewenhoeck found that the musca carnaria deposited 144 eggs, from which, in one month, were produced as many flies; so that supposing one- half of these to be females, there would be in the third month 746,496 flies. The amaz- ing fertility of fish may be illustrated by the gadus morhua, the cod-fish, which will deposit among the rocks 9,000,000, or 10,000,000 of eggs ; and again, the perca fluvia- tilis produces. in April and May not less than 300,000 ova! Dr. Baster.says that he counted 12,144 eggs under the tail of a female lobster, besides those that remained in the ovariwm unprotruded. I have frequently examined the ova of the lobster, and there is one circumstance that, perhaps, deserves notice ; each ovum upon examination will be found to be hexagonal in its form. If we were inclined to be eager on the sub- ject of final causes, we might at once conclude that this form was the one adopted, as afferding facility of packing the greatest number in the least possible space, and we might adduce the structure of the honeycomb as an illustration: the fact, however; is simply this ; that the ova, like all yielding bodies, assume the polyangular form, from the mutual pressure which each sustains from its neighbour. Every person must haye observed the hexagonal bubbles upon the surface of porter and other liquors, froma similar cause. : New Series, vou. 1. Z 354 Dr. Paris on the Physiology of the Egg. [May, your notice, I shall briefly relate the successive operations by which the egg is formed in the body of the animal ; the necessity of more minute detail is superseded by the valuable descriptions of Harvey and Malpighi. ey ohh The rudiments of the ovum are first visible in the ovarium, which, in fact, is nothing but a congeries of vitelli,* or yelks, attached to the spine by a proper membrane ; this repository is denominated by Fabricius, the vilel/artum, or vitellorum racemus, and may be considered as analogous to the ovarium of the mam- malia, or to the roe of fishes. These vrtel/t generally vary in progression from the size of a millet seed to that of an acom; each of which, according to, its maturity, is successively detached from the rest, whence it descends a tube, called, from its resemblance to a funnel, infundibulum, and arrives at the uterus, the internal surface of which is extended by spiral con- volutions ; here the albuminous fluids are secreted, and trans- mitted to the vited/us during its passage to the fundus uteri, or éloaca, where it receives its last addition, the external crust, or shell. The egg thus formed and completed possesses every essential for its subsequent maturation, and requires only the emphatical energy of heat for the developement of its embryon ; this is con- veyed through different media in the different classes of animals. In birds it is applied by incubation,+ but in the amphibia and other animals, the heat of whose bodies is inconsiderable and inefficient, the eggs are deposited in mud_ or. sand, or are exposed to the rays of the sun, by whose prolific. influence myriads of beings are daily cailed into life and activity ; or they are placed in other favourable situations, all of which are too well known to the disciple of Linneus to require any particular notice. It is, however, worthy of remark, that she medium through which heat is applied is suitably varied in the same species in different climates. In Senegal, for instance, the ostrich abandons her eggs to be hatched by the burning sands, while in the more temperate and congenial regions. of the Cape of Good Hope, like other birds, she is inclined to incubation. The different species of estrzs will afford us an illustration of the variety of situations in which the insect tribe deposit their ova; in which they are universally directed by an instinct to ensure a suitable temperature, and appropriate nutriment for the young brood; thus the estrus hemorrhvidalis deposits them in the rectum of the horse, and the 42. ovis in the frontal sinus of sheep, Kc. , * Vitellus, derived a vit, because it contains the embryon. + There are also other animals that accelerate the evolution of their ova by incu tion. Thus bees in a hive generate a considerable quantity of heat without which their eggs would perish ; and the ¢estudo mydas, or common turtle, deposits her eggs ixi the sand, and incubates during the night. f 1821.] Dr. Paris on the Physiology of the Egg. 355 The parts of which the perfect egg consists are: 1. Vitellus, or yelk, with its capsule and cicatricula ; 2. Albumina, with their proper membranes; 3. Chalaze; 4. Folliculus aeris; 5. Com~ mon membranes; 6. Exterior involucrum, or shell; to each of which I shall successively direct my attention. The vitellus, or yelk, is the part formed in vitellario, and is a yellow fluid contained in a membranous capsule, on which a greyish-white circular disk is discerntble ;* this is named cicatri- cula, and is the speck of entity, the germ that is to be developed into the animal. ‘ Jn Aujus gratiam,” says Malpighi, “ reliqua comproducta videntur.” We have here then arrived at the ear- . liest stage in which we can detect the existence of the embryon. Our sHipibEfeck faculties will not enable us to ascend further, and yet, even now, the body is formed as the experiments and obser- vations of Malpighiand Buffon most satisfactorily testify. The yelk is surrounded by amore tenacious fluid, of a light-straw colour, to which the name albumen, or more commonly the white, has been assigned ; this may easily be divided into two separate and dis- tinct portions, each of which is contained in a concentric membrane. They differ from each other considerably in specific gravity, and seem to answer different purposes in the economy of the egg: the consistence of that which is exterior is far less than the one which immediately envelops the yelk, and is con- sumed in the earlier periods of incubation; + while the internal and more viscid albumen seems reserved for the latter stages, when the chick must require a greater proportion of generative matter than at any other period of its evolution. Many of the ancient philosophers imagined that the chick was formed out of the yelk, and that the white afforded nutriment. Such a theory, however, must be at once abandoned, when it is known that the vitellus suffers no other change by incubation than a degree of liquéfaction, and that it is drawn up into the small intestines of the animal,{ by means of an appropriate duct § (ductis stenonis) just before its exclusion. It is then evident tha; * Fabricius supposed it to be a vestige of the ruptured pedunculus, or that portion of membrané by which each yelk is connected to the vitellarium; and AXmilius Parisa- nus contends that it is the semen of the male. + There is a considerable difference discoverable in the milk of mammiferous animals at different periods subsequent to parturition. Fourcroy ascertained that it is mest charged with calcareous phosphates immediately after parturition, and that the propor- tion of them gradually diminishes. " + The vitellus appears to be consumed in the first 10 days after the animal is hatched.— Monro. § Mr. Macartney observes, that the duct by which the yelk communicates with the intestine of the chick does not become entirely obliterated, but leaves a small sac, which remains during the life of the animal. In the snipe, this appendage is of considerable bulk, and on examining its internal structure, we shall find that it is lined with a kind “of villous coat, and that it has numerous folds, or projections, which indicate that it possesses a glandular structure, exhibiting a curious example of the economy of nature in adapting an organ of fetal lite to the exercise of a particular function in the full grown bird, ; . ; ' | Z2 356 ° Dr. Paris omthe Physiology of the Egg. [May, the albuminous. portions * furnish. materials for its evolution, while the vitellus is designed to administer support, until its digestive organs can gain sufficient powers to perform their functions, and the beak a degree of firmness adequate to with- stand the hardness of its natural food. “ Ipsum animal,” says Pliny, “ ev.albo liquore ovi corporatur, cibus ejus in luteo, est.” The albumina, however, besides the office thus assigned to them, discharge another important duty, that of retaining by their non-conducting powers the vital temperature of the crcatricula ; the. wetellus also would seem to answer some other purpose, or why should it be necessary to those birds} whose parents so sedulously supply them with nourishment? At each aad, of the egg, a white, shining, semipellicid body is inserted into the capsule of the yelk, which extends into the albumeu in which it floats. These bodies, from, their supposed resemblance to hail, have gained the name. of chalaze, or gran- dines, and, from having been formerly regarded as the sperm, of the male bird, that of ¢reddles. Bellini‘{ supposes that they are composed of numerous canals, which open into the amnios, or cicairicula, and send out their roots into the whiée for the purpose of forming a communication between them. Dr, Monro,§ how- ever, observes, that ‘if they be canals, they cannot have the least communication with the cavity in which the chick resides at any time, or in any state of the egg, otherwise than as they are both adhering to the membrane of the vitellus, wpon which, or within which, no particular fibres; no canals, are stretched to the cicatricula.” ‘ The chalaxe,” says, Harvey, “ appear to be the poles of the microcosm, and serve to connect the different parts of the egg, and to retain them in their due position. In addition to such ay office, Derham ingeniously conjectures that, as they divide the yelk into two distinct and unequal hemispheres, they must preserve the crcatricuda (let the position of the egg be what it may) in the same situation ; for since the chalaxe are specifically lighter than the white, the yelk is kept buoyant, and the cicatricula, as it resides in the smaller hemi- sphere, will be always uppermost: this, in my opinion, is the true theory of the use of the chalaze ; for such a structure will not only preserve the cicatricula from the dangers of concussion, but by regulating its distance from the source of heat, it will ensure for it a more completely uniform temperature than could otherwise happen, and which is so’ essential to the evolution of * The ingenious experiments of Mr. Hatchett. seem, to show that albumen is the parent fluid from which other animal principles may be derived: he accordingly found that it.was convertible into gelatine and /fibrine. + Pigeons, for example, whose crops John Hunter ascertained to secrete a peculiar fluid during the breeding season for the sustenance of their young. + Bellini de Motu Cordis, prop. ix. § Monro. See his works published by his son, Edin. 1781. 1821.) Dr. Paris on the Physiology of the Ege. 357 the animal, that the smallest irregularity overthrows the nice balance of the different actions that are to mature it, and produces fatal effects. So solicitous, therefore, was Nature to rescue the germ from the consequences of cold, that she has ordained other - provisions, which seem as effective as the chalaxc, for the preser- vation of a due temperature. Thusis the cicatricu/a on all sides surrounded by fluids which are extremely feeble conductors of heat ; these must necessarily retard the escape of caloric, and prevent the otherwise destructive chills which the occasional absence of the parent might induce. The eggs of other animals appear to be protected by an analogous apparatus. ‘hus the ova of frogs, and some other amphibia, are enveloped in spheres of mucilage, which the experiments of Spallanzani show to be essential, as he found that when this gluten was removed, -the égg immediately perished.* [tis certainly true that those fishes who retain their vitality long after their removal from the water, as eel and tench, have the power of secreting a’slimy fluid, with which they envelope their bodies ; while, on the contrary, those who, when drawn on'shore, quickly die, as, for mstarce, mackerel, possess no'such faculty, or, at least, only in a small degree. Is it not, therefore, extremely probable, that this albu- minous matter, by repressing evaporation, and preventing, like the fluids of the egg, the escape of heat by its nonconducting nature, is the principal cause of this peculiar tenacity of life; perhaps a prodigious accumulation of fat may also, under cer- tain circumstances, have a share in producing this effect; the stlurus glanis, which is the fattest of all fresh water fishes, for it grows to the weight of 800lb. lives very long after being taken out of the water. : . Besides fishes, there are other animals who protect themselves from an excess of heat, or cold, by ejecting fluids from the sur- face of their bodies. ‘The common snail is indebted to its: profu- sion of slime for its power of resisting cold. The fable of the salamander being indestructible by fire,.owes its origin to the faculty which this animal possesses of discharging from the numerous pores which are seattered over the surface of its body, a milky fluid, by which it defends itself.for a short time against the fury of the flames. ‘There is an account in the Phil. ‘Trans. ofa knight, at Rome, who cast'a salamander im the fire, which it putout twice, and lived nine months afterwards ! The hen bird seems instinctively conscious of the mischief that would accrue from “an irregular or diminished temperature. She is often seen to make use of her bill to push to the outer ee of the nest those eggs that were nearest the middle, and to ‘bring into the-middle such as lay nearest the sides. The Egyp- * This gluten is not Of the Sainte’ consistence in’ all the dmphibia : it is, for iristance, more abundant and viscid in frogs and toads than it isin lizards‘and newts, 358 —-_ Dr. Paris on the Physiology of the Egg. [May, tians, however, by anice adjustment of their ovens, or mamals* as they are called, succeed in hatching a great pe ye: of the eggs entrusted to their care by artificial heat. The celebrated Reaumur introduced the method into France; and Sir James Hall invented a regulating stove by which an equable tempera~- ture might be easily procured for the same eerecte. During the riod that | was at college, the late Sir Busick Harwood, the ingenious Professor of Anatomy in the University of Cambridge, frequently attempted to develope the egg by the heat of his hot- bed; but he only raised monsters, a result which he attributed to the unsteady application of heat. Jt must, however, be, observed, that deviations from the correct temperature are inju- rious and fatal only in proportion to the grade of vital ener which the ovular embryon possesses.. Thus we learn, from the experiments of Spallanzani,{ that the eggs of insects are better able to sustain the vicissitudes of temperature than those induced with more exalted vitality. Thus it is that the eggs of cold- blooded animals bear with impunity such an increase or decrease of temperature as is sufficient to destroy the animals themselves ; _ for Spallanzani found tadpoles and frogs perished at 110°, but their eggs only at 133°. . If we pursue this inquiry, and quitting the animal kingdom descend into the scale of vegetable existence, where the energies of vitality are still more feeble and obscure, we shail find the same relative power of sustaining heat or cold between the plant and the seed, as I have stated to exist between the animal and its egg. , ‘With respect to the relative destructive influence of vicissi- tude of temperature upon the egg of birds in different stages of developement, it would appear, from the interesting experiments of Reaumur, that it is more destructive in the earlier stages. of incubation, especially diminution of. temperature, but that increased heat 1s more injurious in the advanced states of deve- lopement. After having related the agencies of heat and cold, I may mention that light has also been found by Michelotti,§ of Turin, * The inhabitants of the single village Berme, situated in the Delta, about 20 leagues from Cairo, among whom this art is alone practised, give life by means of their memais to two-thirds of the eggs entrusted to their care, amounting in one season, which continues but for six months, to the astonishing sum total of 92,600,000. Corneille le . Bruyn, tom. ii. has collected the observations of many travellers on this subject. Father Sichard also gives us an interesting account of the same art; and Reaumur has pub- lished a very complete work, illustrated with numerous engravings. + The ancients were acquainted with the possibility of hatching eggs artificially. Pliny (lib. x. cap. 55) says, that eggs laid upon beds of straw in a warm place, and after being regularly turned from time to time, would, at the proper period, disclose the ‘included animal... Pliny moreover states, that Livia hatched a chicken by the warmth of her bosom. Gesner and Aldrovandus have collected the passages of the ancients, and those of the authors of their own time, that mention the method of hatching eggs by dung. = Spallanzani. Tracts on the Nature of Animals and Vegetables. § Journal de Physique, Ventose, An. ix. 1821.] On ihe Expansion of the Functions f (ax), f (x, y), &c. 359 to exert a decided influence on the ova of animals ; he placed the eggs of different species of phalene in transparent and. opaque jars, when he uniformly found that those in the black jars were first hatched; he, therefore, concludes that light is preju- dicial to the developement of the egg: thus we find, says. he, that the eggs of many birds are furnished with an opaque shell, as those of birds, and that if it be delicate, the parent deposits them in dark and concealed places.” Before any conclusion can be legitimately deduced from the experiments of Michelotti, it ought to be shown that the temperature in both jars was the same; for unless this were established by actual experiment, we might be inclined to draw an opposite inference from the different radiating powers of black and white surfaces. (T'o be continued.) ARTICLE YV, On the \Exfinision of the Functions f (x), f (a, y), f (®) Yy %); SC~ By Mr. James Adams. | (To the Editor of the Annals of Philosophy.) SIR, ; Stonehouse, near Plymouth, March 5, 1821. Tue usual method of expanding the functions f(x), f (*, ¥), SF (4, 4,%), f (%,Y, % v), &e. being from their nature very trouble- some, I beg to recommend the following, which, I trust, will be found more convenient and expeditious ; the insertion of which in the Annals of Philosophy will oblige, Sir, Your humble servant, : JAMES ADAMS. ae Problem 1.—It is required to develope f (a), or any function of x. ; 7 : Let f (x) = u; then place the symbols d, d®, d°, &c. succes- sively before the character wu; likewise the symbols d and A successively before the assumed series x + a? + 2° + a+ + &e. together with the corresponding numerical coefficients in the following manner: du f d*u Bu > At iat ae Q RCD a titi OR 3 4. &c. we shall then iaaS* + pag 4? + rreeaeot + : th Bu d 1.2da? 1.2.34 2 have f(x + Aa) = u+ Ar + Seo Aatt Ae + Sor "| ee fe ee eS ee —E —EEEE—E—EEs + | = | (2 + # 4+ x) jo suoisuedxo oy} ur sudis pue syuatoyjooo oy} Sup ‘zeUUeME SuIMOTIOF Oy} Ut L4 syuaroyjooo je1swnu Suipuodsaii109 ay} YT 1943080} $x pu ‘f “x Jo suoTeuIquios SuIMOTOF oY} aL0Joq Y pue p sfoq -wis dy} astMoyl] $2 Joyovrleyo oy} ont Jy aes Sem “om

AV sp A Av mp ht | = fip* & P&B ° 1) ip *xps*y / as 2 ©= a? - z v cd o G 9 “ . 4 sc ieccaigeamedagae ; a § Ay’ ty 1 sp sh AV uM np fr RV eV Nop * “* 7V ap i a: er php ES" Be ~S ap hpe*y : ip? xp hip 3 ry'h ft . —¥ ? 69a. — | hv lkhy — Fy FV ORY np ot h eV hy “2 wh kviry Pp - | a ar A : UP T’E°S* lh ev PE*°S* I ev PSB" I a 2 x ' a ’ p > SE tens eS aes eo s 4 V i yp gv gt V n ep gv gt V np gt a i V np BS = npg eres tna sa tsne soe Cay 7 (‘9) ‘¢q) “2 p 04 eS “m yp 07 Surpuodsaxioo suo, 1E+h +2) on oy 04 Surpuodserz0o sua], c@+h +) Surpuodsazz09 SULA, sts) 362 Onthe Expansion of the Functions f (x), f (x, y), &e. [May Hence we obtain f(x + At, y + Ay,z+ Az) =ut+aA +B+C+ D+ &e. | | In like manner, we may expand the function f(a, y, x, v), for the several combinations of the variables abstracting the numeral coeflicients are as follow: | (wt+ytetrsrty+tztv ! (r+ y+ vps rpuyt ret yp trvtyzt+x2t+yv +20 + v? (T+eytertvpseHK+ecYPt+rVP@trvr+_y+ yx t+ yx? + yv + 2° + &e. to 20'terms. ~ wW+eytetvyertryprrPr + ev +yt +yx + ye? + ye +24 + &e. to 35 terms. Bo ra CR Pe Win a Sa Awe VeTS Ht aaeine-6 By prefixing the symbols A, d, d®, d’, &c. before the variables, X,Y, %, v, and w, as in the preceding problems, we readily obtain the expansion of f(x, y, z, v), and so on fora greater number of variables. | In the foregoing expansions, it will be observed that the index of the symbol d placed before ‘wu is equal to the sum of the indices in the several combinations of the variables, the symbols d and A are simply placed before the variables and their powers, and the numeral coefficients in the denominators are also governed by the indices of the variables. ‘Thus the differential coefficient . . OF3t4u =du of 2° y° x* will be found to be 7- % (1.2.3).2.3.4)da*.dy.dad and the differential coefficient of x” y" x”, or of u, will be Qe rnrtey ; fi.d..m U.2..: 90.92. Hadad pudw.e three variables, which may be extended at pleasure.—(See Woodhouse’s “ Analytical Calculations,” p. 86... The differential of a function being the second term of its developement, or that part of the expansion of a function which contains the first powers only of the increments d x, dy, dz, | &c. It will be perceived that the differential of f (x) consists of one term of A (xv, y) of two terms, of f(x, y, x) of three terms, &c. Therefore by changing A x into d x; A y intod y, A x into dx, &c. we have | d d df(a)=du=“drdf(ey=dusS da + dy, eneral form for df(z,yz)=du= “< dxux+ = dy + dx, &e. — d x, = d y, &c. are called partial differentials, and du du du —, —, —, Kc. are called differential coefficients. aw dy dz 1821.] Dr. Yellowly on Dr. Prout’s Estimate of Mortality. 363 ArTiIcLe VI. Observations on Dr. Prout’s Estimate of mot odded from the Operation of Lithotomy. By John Yelloly, MD, FRS. &c. (To the Editor of the Annals of Philosophy.) DEAR SIR, Carrow Abbey, Norwich, March 30, 1821, I Bue to notice, through the Annals of Philosophy, an inac- curacy into which Dr. Prout has inadvertently fallen, in the statement which he has given, in his valuable work on the Diseases of the Urine,* of the mortality occurring in the opera- tion of lithotomy, in the Norfolk and Norwich Hospital; and in the deduction which he has made, as to the mean ratio of morta- lity from that operation, over the whole kingdom. Dr. Prout quotes Dr. Marcet’s published account of the cases which occurred in' the Norfolk and Norwich Hospital up to 1816, and infers, that as the mortality which took place in indi- viduals below puberty, was 1 in 18, while that in adults, was 1 in 43, the mortality of the whole must be 1 in 118, or the mean between the two proportions. ' It is obvious, however, that this calculation could only be correct, if the number of deaths at those two respective periods were equal ; but as this is not the case, the mean ratio can only be obtained, by dividing the whole number of cases, by the whole number of deaths, which Dr. Marcet does, and thus gives the mortality as 1 in 71, the deaths bemg 70 in.506 cases. Taking this as the accurate proportion of deaths in the Norfolk and Norwich Hospital, up to the year 1816, (which, from my own inspection I can state to be the case,) the proportional mor- tality, from the operation of lithotomy in the whole kingdom, as inferred by Dr. Prout, from the mean of that in the Bristol, Leeds, and Norwich Hospitals, will be about 1 in 61, instead of 1 in 73, which he states it to be. I remain, dear Sir, yours sincerely, J. YELLOLY. * Page 218. ‘ ++ Marcet on Calculous Disorders, p. 26. iB ev ‘OUT, UL “YOIMUeeT Jo 189M FO of Le | "GHON 1,88 ,L) 00G “IT ‘(TT ‘Aoung wera es -:40dsox) ‘huapooy ayy fo edi ayy yo pday qouinog pvarwopouoajazy v fo synsaay ‘TIA FIOMUYy + 399) 1-69] 6-69, 9-19] 0-8F[6z|001| BF-19] OB-15|0E-65| B& |8-8S/GL-BC| $B | 16 |88-6B) L8-6e) 18-68/ G0-1109-€L) 122) 69-31) 188-62) 09-86) 09-0¢)8IST Ma < j.¢1| FLL] &-9L 8-29] F-LF|6E1001| F8-0¢] 88-06 e9-28| Os |€-26] O1-Z¢| CT | 8 | LS-63] 18-63) L8-63/ €8-0] 61-69) 082, £6-1 1] 188-63) 60-66 O¢-O8/GI8I tod 6.69| L-11/ 6-19: FSS) &FSIEE 00! 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TL |B0-08) £0-06) 20-08|2e-0/ 0 1D 09 RN OO 19 oA Ge > lo oe) ON 3 ‘Sumysry | OSS SSH THA ASoO Tse io iT.) 5 = | ‘srosiom qeug |" XT“ FS" RZSTT’ aR ° — po z-. ‘Soper. setteyy “foe PHN ee ee ee oer LE a nat NaN NTH TOON ie ot |__“Soreq-zepog |: 3 8 ° ; fy ma te conte or Cl < y “aorta SSSSSesSeses m= GN Taan OO Ow ‘orey | ~ PD Pree Ot be a 3 : ~ te i in . “ale = 80,J =OOooocoo=oe-n not | Kys qouardho ay | MOOS SNe BM Sst] RSS pd oe Beinoonmomneon | paw A SPNOPS YAM ITV See lane lance Mate entice tone Mian Mien Mae Bien! CO rs = y end pee tome IN “AMS IQII W | WHO Hay. nora Qiao ‘mqmy | AAS SSS SSSA LESS poe pee pee . ~- oO mM | HLLIA ESN S | oes, — ee 4 oon Oe DANORNDA snjauing | PO RAR Ae Na wae Q " ‘ c P snqeVyg G9. 09. Qe vA A aKNO90:9%: |e BR 5 ; MOCO DIMM A winger | oa smensomty | 32 Nea NNYNNN WR |ses NO w aon snynuinsox1y SC he eee | eee = | ; ReKeKtODAMMANMe | OO] SULIT | SRORS ake eee of SRS saat (aneanenanaen | see be, is) Jo raquinu [20 J, onsets it eT ae riloinion. i ACN HAM Scie raarn [wes a P10 remo S : " MS eye gs rin ba) 13 GR_GO.O2 OP mt mt em HOD HIS = mM SI 1,99 © |. co é m1) lod fey respi ion ol fa Si mmaanrmmnaermm | cans A a9 99.29 wi as: | esotratot wou | NaS ano : VNAN AMA MAH | OMS 3) ; H{0% 4103 1c silo fon R Cl rE HORNR gv terr on last < a 2 i ‘ [len eae tion een i) N o oo | xa c & NOOWMCRNONK VANE D 29°882 Greatest range of the mercuryin October ..........., 2: 190 Least ditto, ditto,{in August. oo es. ec ae eee tian a 0-780 Greatest annual variation in 24 hours in October. ...... 0-980 Least of the greatest variations in 24 hours inJune .... 0°360 Spaces described by the oscillations of the mercury. ... 71°650° eee of changes, caused by the variations in the weight of the atmospheric column ..........00.005 2i1 , Day and Night Thermometer. Greatest thermometrical heat, June 26. Wind W..... 87:00 : cold, Jan. 15. Wind N.E.... 14:00 Annual range of the thermometer hetween the extremes. 73:00 Annual mean temperature of the atmosphere.......... 50°13 Greatest range in June s oo sss wnmgich Sah Knls oince wale Hee 47:00: Least of the greatest ranges in October... .........0+ 25°00 Annualigieen range. 5" wAk ais lags wes bo ie's Moe ade Fob 34:00 Greatest annual variation in 24 hours in June. ........ 30°00 Least of the greatest variations in 24 hoursin December 14:00 De Luc’s Whalebone Hygrometer. Greatest humidity of the atmosphere, 15 times. ........100°0 Greatest dryness of ditto on July 1 and 25. ..... ttaeeee COU Annual range of the index between the extremes. ...... 67:0 Annual mean of the hygrometer at 8 a. mM...-.es.00+445 67°9 GUO Pm Tce SEF 1821.] Dr. Burney’s Meteorological Journal kept at Gosport. 367 Degrees, Annual mean of the hygrometer at 2 p.m. .......... ». 584 at 8,2, and 8 o’clock.. .. 65°9 Greatest. mean humidity of the atmosphere in January .. 81-1. Greatest mean dryness of the atmosphere in June....... 51°3 / Position of the Winds. From North to North-east ...... etetenemerditie th we O53. North-east to East.......... nat as Ride ig ed ARDS 384 Raitt: 40 Soe eae ie oi wehbe bin Syeibinn'e 2 sanuiianis 54 South-east £0 Mowb. | Or eG) ies anbielacwie’'s piece sjmieu 26. Pr tEe Lh DN GAN Eee EIT ii ig re bclascns'gs je 5, 4iaivec hs BOUin lee, cel oi) 89 36 South-west.tonW Ost sasccsuisasitlive awed dele es « Fre? | West to. North-west. .... 0... pba eh "a PE MALS OL; 2 71z North-west to: North -ssco-oeareuieet De UW aN le eds 53+ 366 Clouds agreeably to the Nomenclature ; ov the Number of Days on which each Modification has appeared. ; Days A ARE Ricole x: 5,2 sesaknnd bine 1a teres qinlbeien n kbiie “code pega 208 (CUROCITOIIUS « socitria.aow wednnal Wa reediic mi panel eneat hadi ie anaes «499 ABELL ALS, noice ain: deni nem Lubcein tn week wegiate 69/218 age ey RO Fine ue ors 283 ORT a EE diesen: nae halainde “& PETE ore mA Chinn cmd Secel t 50... SMEG A’ o-a.0:s.s skin inl dco leaching ive SHERRI a Parhelie: On MOCKSUNAL; oa isia sbretecece maid wiele «blige! Na

29°875 | '39:069)40:310) 91-40 | 124 17) | Match ......) 29°76b.4 32355 | 29°76—), 39 645/41-451}, 0:50), 10] 2b BITE, a sige asin 29°794,| , 45°500-) -. 29°795 | 44°533/47-333)0°909) . 6) 24), May oso. 29°632 | 49516 | 29°602 | 47-870|50° 5:20 | 19 | 12° June v2.24 29°838 } 55066 | 29°887'| 52-966/55°533) 1°60) 313 | 17 Taly c..s-.u}) 29°844:| |. 577549, ]) 29°788.| 55-580 1-800]; 9] 2%. BRE ohne daca 29°621 55°645 |. 29°627 | 53°590/56:806| 2-20 13 |, 18: Sept... 29°792 | 51°100 | 29-777 | 50-060/52:633}. 1-20 )° 12) 18 | QO AS oe? 29°499- | A43*193 | 29480 | 42°742/44-419} 2°50 | 12°} 19° Nove. -.ss+-) 299749 | 40/633; | , 29°764:,) 40°633/42°133)" 1°70) Lb | Ad) De¢.\....+0++-{ 29:877 |. 39-032, |. 29:883,)| .89;129|39-483| 2-20] 16 | 15... Aver. of'year.| 29-754 |. 45-383 29747 141 \Aseseie 124} 23°50 | 147 le19: ANNUAL. RESULTS, hryg MORNING... BAROMETER, THERMOMETER .. Observations. Aides Wind, Highest, Jan, 9 .... SW ..,. 30°88. June 26. apt teeeee se ceny Warcars Sant Lowest, Oct. 17 Sona” eeee 22°58 Jan, ao ener aie eta eeeee NW .... 1?" EVENING. Highest; Jan. 8 .... SW... 61 30:89 | June 250.....0.0.0. wees NOW, OTe Lowest, Oct, lt: ic RE eeeene 28°66. Jan. 18 .. ee ewer Ue. sie. NEVER * go Weather. Days, Wind. imes, Seeeeraetr eee Reese eet eeee 219° } Nand NE. eee ere eteeesee 19 Rain Or snows. .........e0000- LAT BiandiS Bis . bis eek lbs ce) OU! , ar S.and Sw. cade dings atad 67 366 We: On IN: W voice nitenakacssiios 188 366 Extreme Cold and Heat, by Six’s Thermometer. Coldest, Jan. 18, Wind NW, ..cscsececceces Helacieke one below Zero Hottest, June 26, Wind N W. eeeereve **e err een eee eaeeneeeeanan ea 79° ; Mean temperature for 1820, ee eeer ee ee eeeeeaeeeeeeree ee ee tee 46°7427 | Result of two Rain Gauges. a In, 100 Centre of the Kinfauns Garden, about 20 feet above the level of thefsea.......... 23°5 Kinfauns Castle, 129 feet . hen eee eee 185 ¥821.] Capt. Undrell’s Ascent to the Summitof Mont Blanc. 373 ARTICLE <. An. Account of an. Ascent: to the Summit of .Mont...Blanc, in August, 1819... By Capt. J. Undrell, RN. (To the’ Editor of the Annals of Philosophy) SIR, ~ | | London, March 23, 1821. HAVING seen in your journal an aecount of an unsuccessful effort to reach the summit of Mont Blanc, perhaps you may give room for the detail of a prior attempt attended with better fortune. The letter. I send you is a transcript of one written a short time after the ascent, and never, as you will perceive, intended for publication; but, as the relation may excite some interest from | the melancholy event attending a subsequent failure, you may deem it worth a place’in.your publication, though possessing’ no. requisite for a work solely dedicated to the purposes of science. Iam, Sir, your very humble servant, ) J. UNDRELL. ‘DEAR Berne, Aug. 29, 1819. You ‘may feel curious to have the detail of my late ascent’to ‘Mont Blanc. I need not remind you that I had long intended making the attempt, but rather next year, upon my return from Italy, than at this period. In truth, when I left Geneva’ for Chamouny, on the 4th ult. the weather was so unfavourable that I'scareely expected even to see the summit of the mountain ; and when the following day at Sallenche, I caught a glimpse Of. ‘it at sun-rise, I deemed myself fortunate, as it became in a’ few “minutes overcast. In the afternoon I reached the Prieuré,.'the rain falling in torrents, ‘and although it cleared up a little’ the “next morning, all the heights were still cloud-capt. Z On the 7th, from that singular ice-bound is.e, called’ the Jardin, at the extremity of the magnificent glacier of Taléfre, which branches to the eastward from the upper part of the Mer de Glace, I had the first clear view of the top of Mont Blane, ‘which is ‘thence. beheld in..a..most: imposing..form,. rising ..so abruptly for many thousand feet, that the snow cannot rest upon its sides. : | : 7 On the 8th, the weather.was. unsettled ; and.on'the 9th; [set off for Martigny, and had proceeded seven or eight miles towards the Téte Noire, when, turning to take a kind of farewell look“at _-the. mountain, then, quite clear,:as Iwas about to.enter a. path, which, from its direction, would have concealed it»altogethersL all at once determined to réturn, and’ make an attempt. the'ensu- ‘ing morning... My guide, Josef Marie Couttet, who had attended “me in: every excursion, was’ delighted» at»this) resolution, and quite confident that the weather would prove favourable ‘in spite 374 | ‘Capt. Undrell’s Account of an » (May, -of what seemed to me strongly to indicate the contrary. The result justified his assumption. | In these regions there-is no barometer equal to the local expe- rience of the inhabitants, which may almost invariably be relied on. From auguring differently of appearances on quitting Geneva, | had, as stated before; Se ce in idea, the attempt till next year, and was thus imperfectly provided. with instru- ments which cannot be got at Chamouny. Old Dr. Paccard supplied me with all he had, but I could not procure any good barometers, which | most wanted. ; In addition to Couttet, I engaged five other guides,* who had all accompanied two American gentlemen a hott time before, and left the Prieuré about five, a.m. on the 10th. We soon rxeached the base of the mountain, and after ascending, about an hour and a half, through a wood of firs and larches to the east of the Glacier+des Bossons, reached a little cottage, the highest habitation, where we breakfasted. At half-past six, we departed, the thermometer being then 43°}; thesun shining bright upon the Dome du Goité, and the western heights of the valley of Chamouny, which first receive his rays in consequence of the direction of the mountains. At twenty minutes past seven, we stopped at a large stone called Pierre Pinte. from whence the -path to the “ dernier gazon” is steep, winding, and difficult, ene to the right the deep ravine by the side of the Bossons, which name is now applied to the ch extent of the glaciers towards. the Aiguille du Midi and the Montagne de la Cote, ‘including indeed a portion of what is properly that of Taconay. it was half-past eight before we Satna the last land,{ when “we took a ladder, which is constantly kept there for these excur- ~Sions, and, crossing a ravine covered with loose stones and huge fragments of rock, ascended the Bossons, over which con- egealed mass, the more lofty adjoining glacier, and the snows above them, our future path lay. Our shoes. were fitted with the cram- pons used on nck Peoations. without which it would have been .ampossible to have held footing; and we had also long. staves * These were Pierre Carrier, Alexis Du Vaussoux, Mathieu Balmaty, Eugene ‘Couttet, cousin, and David Couttet, brother of the principal leader. I give their own ‘method of spelling their names. All ofthese seem to have attended Dr. Du Hamel and shis party; and the first, an excellent man, with two others, who had never before attempted the ascent, perished. The Doctor must be mistaken in asserting that poor Carrier had been |! times at the top of Mont Blanc. He has confounded the unsuc- ~ , : (To the Editor of the Annals of Philosophy.) SIR, - . ) . Bow, March 21, 1821. 1 am unwilling to intrude the subject of oil_gas again upon your readers; but there are some observations made upon my former paper by a correspondent in the last number of the Annals, to which I must claim permission to reply. . This gen- tleman, whoever he may be, has said more (unintentionally, no» doubt) against the management of coal gas companies in general, : than could be deduced from, any, thing | have written. My object was only to prove the inferiority of coal gas, when brought in comparison with that of oil; but he has shown that some great. mismanagement exists in all the companies, excepting those of Sheffield and Derby; and if the statement respecting the latter be correct, the management of the Sheffield Company may also» come in for its share of blame. : I must still persist in my assertion, notwithstanding your cor- respondent differs from me, that the advantages attendant on the London Chartered Company, are greater than any other possess. It must be allowed, that to have the greatest number of lights in the smallest. compass is the highest advantage which a gas light establishment can have. The cheapness of coal and labour is of little benefit, unless there 1s an ample demand for the gas; and what place is likely to compete with London in this respect? If you compare this Company’s main with the number of lights upon it, 1 should think no provincial city or town could. in any way equal it. i Your correspondent says, that the'selling price of coal gas at Sheffield is upon the average 10s. 6d. per 1000 cube feet, and at. this price, it yields a profit of lO percent. He then asks some- what triumphantly, what I shall say, when informed that at Derby, gas is sold at 7s. 6d. per 1000 cube feet, and that the Company “ calculates” to share a profit of 10 percent.? To this 384 Mr: Ricardo’s further Observations ona (May, I can, pales reply, that without doubting your: correspondent’s veracity, 1 must beg leave to doubt'the fact: till the Company’s calculation is realised ;_ besides, if Sheffield retails its gas at 10s, 6d. with, a profit of only 10 spengonny. there must. be some extraordinary and unaccountable advantages attendant on Derby, or some gross mismanagement on Sheffield, as I cannot see why the latter, should not be able to sell their gas as low as the former, and at that rate the profits ought to be nearer 60 per cent. than 10 per cent. From a paper now before me, the Derby Company appears to be but very recently established, and the promoters of it are‘makingytheir calculations by antici- pation. One circumstance I beg to mention, where I conceive them to be completely. in,errer;, and if their calculations of profit, are made from such data;, they wall certainly be deceived, This paper states, that 1000 cube feet of coal gas are equal to.70 lbs. of candles. This, | believe, is at variance with every recorded | experiment. that has been tried; and more particularly with those of Mr. Accum, one of the chief promoters and warmest advo- cates of coal gas establishments. In my former paper; I have given the result of his trials.on this subject, and, according to them, supposing: these experiments to have been made with. candles six to the pound, instead’ of-eight, each candle lasting: six hours, a pound would be. equal’ to 24 cube feet of coal gas, so: that 1000:cube feet would be equal to somewhat less than 42 Ibs. instead of 70 lbs.as stated im the Derby report. Your correspondent next draws a‘comparison between my calculation of the expences of oil gas and the Sheffield coal gas; but I cannot admit that one of the former is equal only to three of the latter: [am convinced it is fully equal to four, in drawing: the medium between the two; and allowing it to be as one to: three and a-half, [ trust | have made every necessary allowance. In tnat case 1000 cube feet of oil gas which cost 30s. would: sell? for the same price as 3,500 of coal gas, instead of 3000 ; that is, 1d. 16s. Gd. yielding ‘a profit of 22 per cent. instead of 10 per: cent. as stated by your correspondent. | I am willing to allow that some of these calculations show better on paper than in reality, and that there are always some. i670 and unavoidable expenses which ’cannot be immediately> oreseen, but which, however, it becomes necessary fora newly established Company to guard: against by’a high price. This: may always be much more: easily lowered than raised; buat’ whatever these contingencies may be, they must, from the nature. of the two establishments, be greater in the coal’than in the oil. In-estimating the profits, it must always be done-with the consi- deration of a certain demand for a given number of lights: inte- rest:on capital, and expences of management toa certain extent, must be incurred, whether there are few or many lights required ; but, when these are: properly balanced: by the demand, a profit approximating to what 1 haes stated may ok expected, : 1821.) Comparative View of Oil and Coal Gas. 8385 Your correspondent says, that the more unpleasant the gas is, the more readily is its escape detected. I am very willmg to allow, that though not so unpleasant as coal gas, oil gas is quite enough so to insure detection. The only question in dispute then is, which may be procured the cheapest. I think I have roved that the advantages rest with oil gas; but even suppos- ing it were as expensive as coal gas, its superiority in every other respect will, when its use.is as well known, give it a decided preference. I have subjoined a table of the cost*of gas at 12 different establishments. This has been kindly fur- nished me by a friend, who undertook, from their printed rate cards, to make the necessary calculations, and which, I believe, may be strictly depended on for their accuracy. This table will be a sufficient proof that in estimating the selling price of gas generally at 15s. per 1000 cubic feet, [ have not been so.wrong as your correspondent has assumed ; but, on the contrary, that my estimate has been too low instead of too high. The average rice for the 12 establishments quoted is 16s. 10d. instead of 15s. i have been unsuccessful in my endeavours to procure rate tables either of the Sheffield or Derby companies... I have seen. a printed paper from Derby which states the. znteniion of the promoters of that establishment to sell gas at 7s. Od. per 1000 cubic feet; but I have seen no document from which it can be’. inferred that they actually do so sell it. ao Were I to hazard an opinion on the cause of such small profits as are generally known to accrue even from gas establish- ments which make high charges, I should attribute it to the Sat mode of charging for light; namely, by the number of burners used instead of by the quantity of gas consumed ; in the former way, there is no check upon the consumer; and every one who walks the streets in the evening must observe the extravagant waste of gas in the different shops—an extrava- gance which does not benefit the consumer, while it ve seriously injures the Company providing the gas. This’ might be obviated by the use of the gas meter: the perfection to which this machine is now brought, and the correctness with which it registers the quantity of gas that passes through it, will ensure its preference over every mode of estimating the ee of gas both to the Companies, and the consumers, if it ecame generally adopted. | New Series, VOL. 1. 2B 368 Comparative View of Oilyand Coal Gas. May, Yable a the Prices at which Gas is charged per 1000 Feet, calcu- lated from the Rates of various Places, taking the large Argand Burner until 10 0’Clock as the Standard, and reckoning the Consumption of Gas at five Cubic Feet per Hour for such Burner, and the Number of Hours in one Year to be 1100, or 31, on the Average for 313 Days. “ish Amin change, Oss et emma tee 000 etre hass: dl £8. id. Peeds! uw bas. wwe [4 90 0 5500 0 14.6 (Edinburghe.. . yas. 4 4°90 0 15 3 *Newcastle, cee ak 4.64 of Watts waa joe au ). 4. 10:20 0 1 4 W orcésters iia ood beau 4 12 0 0 6 8 MBborley sss. I eed. j4:14 6 Preston. ).i..0... SOE ze i 4 14 ey OMe abonidom uh 0G), eee vies J4 16 oe ! (A fibiverpool 1... ~J4 16 0 Bridtokiahaaas cb, gaye 416 04 oe Chester ..0).85.0 +4 16 0. oe | Oxtorad. std oicns\ jos0s 5) 32: 0: bl 0. 4 _The average charge for 1000 cube feet of the 12 towns is 16s, 10d. mite iit AAS ey 4 i} er ; ; _. P,.S.—Sinee writing the above, I have been successful in obtaining a Sheffield rate card. Calculating on the same scale as the others have been done, I find the cost. of gas is, 17s. per 1000 _cube feet instead of 12s. as stated by your correspondent... The highest discount which they allowed. is 20 per cent..on large _payments : this, taking the medinm, would average the gas at er. 2d. imstead of 10s. 6d.: the quantity suld by the meter at any _of the works is so small, I understand, that no calculation can be made from. that mode of charging... The difficulty which my » friends have had in procuring me the, rate cards has made me ‘so late in transmitting this paper to you; and this last, of Shef- field, the most important of all, 1 have only obtained this morn- ‘ng. I am aware that the time of your receiving communications has elapsed; I cannot any longer encroach upon your indul- gence ; and instead of rewriting the paper altogether, which I should not be able to do for this month’s insertion, I must request you will insert this as a postscript. Although I enter- tained some very considerable doubts of your correspondent’s correctness, I did not like to express them till I had satisfactory proofs instead of mere surmise ; these are furnished by the rate table before me; and the charge which your correspondent \ 1821.] On Capt. Kater’s Experiments on the Pendulum. 387 brought against me of not obtaining better information before L estimated the price of gas ‘at what | did im my former paper, may certainly be retorted upon him, for not having made his state-. ments more correct than he has done. Iam, however, indebted to him for affording me an opportunity, not only of confirming _ my former statement, but of showing that, instead of exaggerat- ing the superiority of oil gas in point of economy, L have under- rated it, and that its advantages are much greater than I had myself conceived before I entered into this more complete inves- tigation. Had it been practicable, it would not have been uninteresting to have shown what dividends are paid by the above enumerated Companies; how many pay 10s. per cent..; how many pay more; how many pay less; and how many pay none at all. I am, yours, &c. M. Ricarpo. March 23, 1821. ArtTicLe XI. Remarks on Capt, Kater’s Experiments on the Length of the . Pendulum. | (To the Editor of the Annals of Philosophy.) SIR, As notices of Capt. Kater’s experiments on the length of the pendulum have occasionally appeared in your journal, the fol- lowing remarks relative to that subject may, perhaps, be allowed a place init. I am, &c. &c. | X. ee ie An article appeared in the Edinburgh Review for November, ~ 1820, giving an account of Capt. Kater’s experiments for deter- ‘mining the length of the pendulum at different stations in Great ‘Britain ; and the writer has made some observations which seem tobe founded in an erroneous view of some of Capt. Kater’s “statements. At p. 343, the following passage occurs > “ Capt. Kater seems to have mistaken the import of Dr. Young’s statement, when he uses this correction for the attrac- tion of the ‘elevated part interposed between the general surface and the place of observation, nothing being said of dateral attraction caused by surrounding matter. But Capt. K. applies the correction for the error produced by hills lying round the puint of observation.” On this passage I have to remark, that Capt. Kater does not ‘apply the correction for the error produced by hills lyig round ‘the point of observation. Indeed the only proof which this writer brings to support his charge is, that Capt. K. says, “ the B 2 ! A 388 On Capt, Kater’s Experiments on the Pendulum. [May, height of the station at Unst was found to be 28 feet above low water ; whence we have 0°12 for the correction, as deduced from the squares of the distances from the earth’s centre ; and as the station at Unst was surrounded by hills composed of serpentine, I shall take 0-12 x 4 = 0-06 for the correction to be applied in order to obtain the number of vibrations which would be made at the level of the sea.—(Phil. Trans. 1819, Part IIL. p. 354.) Here it is surely obvious that he introduces the consideration of the nature of the hills surrounding his station, not for the pur- pose of applying a correction for their attraction, but as afford- ing a presumption of what might be the nature of the substratum of the place of observation ;—a consideration which Dr. Young’s rule requires to be introduced, as the correction varies not only with the nature ofthe eminence, but also with its density. Having thus attempted to make out that Capt. K. has mistaken and misapplied Dr. Y.’s rule, this writer next proceeds to find fault with the quantity deduced from the rule. After quoting Dr. Y.’s account of his correction from the Phil. Trans. 1819, Part I. p. 93, and stating that the correction for a tract of table land of a mile in thickness will be 5&8. of the whole correction for elevation ; he proceeds to remark, “If this be the case, we cannot perceive the grounds on which Capt: K: takes 4, only a little less than ,6,6, for the correction applicable to an elevation of 28 feet, in the actual state of the superficial inequalities. We may have overlooked some step in his reasoning, or Dr. Y.’s ; but we feel bound to state our difficulty as it occurs.” . There is doubtless some difficulty in the case; but from, Dr. Y.’s own words, it appears that he considers “ that for a place situated on an elevated table land of a mile in thickness, of the mean density of the earth, the allowance for elevation would be reduced to one-half; and in almost any ose that could be chosen for the experiments, “it must remain less than three fourths of the whole correction deduced immediately from: the duplicate proportion of the distances from the earth’s centre.” Thus the correction (as Capt. K. remarks) will vary according to the nature of the elevation, and also its density from one-half to three-fourths of the quantity before deduced. In any situation it will not be reduced less than one-half; nor more than three- fourths. These considerations seem to have been overlooked by this writer; still, however, I do not mean to assert, that the numbers are absolutely correct. It is to be wished that both Capt. K. and Dr. Y. had given a more detailed aecount of the method of finding this correction. | 7 In a subsequent page (347), this writer observes; “ from the great disturbing force at Arbury Hill, we may infer that there exists very near it a mass of matter of considerable density. Capt. K. conjectures that this mass 7s Mount Sorrel, which con- sists of granite, and other rocks of primitive formation are Situated in its vicinity.” 1821.] Proceedings of Philosophical Societies. 389 ~Now here it is to be observed, that: Capt. K.’s conjecture is misrepresented, as will be clear from a reference to his own words, Phil. Trans. 1819, Part [II. p. 425: “It would be no improbable conjecture, that the sudden increase of gravitation, observed at Arbury Hill, may be occa- sioned by a rock of primitive formation approaching tke surface of the earth in the vicinity of that station.” | He then subjoins in a note, “I find the ccnjecture I have hazarded remarkably supported by fact; for on consulting Smith’s Geological Map of England, it appears that Mount Sorrel, a mass of granite, is situated, together with other rocks of primitive formation, about 30 miles to the N of Arbury Hill.” his is surely very different from saying that the attracting mass 7s Mount Sorrel. That rock is obviously mentioned only to show the probability that granite may form the substratum of some point near the place of observation. / , ~ ARTICLE XII. Proceedings of Philosophical Societies. ROYAL SOCIETY. April 5.—A paper was read, On the Separation of Iron from other Metals,” by J. F. W. Herschel, Esq. Mr. Herschel proposes, as the basis of a mgorous separation of iron from the metals not precipitated by sulphuretted hydro- gen which it most usually contaminates (manganese, cerium, nickel, and cobalt), a peculiarity in the peroxide of iron, in virtue of which it is incapable of subsisting in a neutral solution at the boiling temperature. If a solution of this peroxide be neutral- ized when cold, and then heated, a portion is deposited in the state of a subsalt, and the liquid becomes acid. If allowed to cool, and again neutralized, a fresh portion of the metallic con- tents separates on re-applying the heat, and so on, till the quan- tity held in solution is no longer sensible to the most delicate reagents. If, on the other hand, the neutralization be performed while actually boiling, we attain this limit at one operation. Hence Mr. Herschel recommends the following process : Having peroxidized, by means of nitric acid, a solution containing iron and any ofthe above-mentioned metals, drop into it, whele borl- ing, carbonate of ammonia, till the acid reaction is entirely destroyed, and even going a little beyond the point of exact neu- tralization. ‘Vhe whole of the iron to the last atom is sepa- rated, while the liquid retains in solution the other metallic oxides, as well as the minute portion of their carbonates due to a 390 Proceedings of Philosophical Societies. — [Mav,. trifling excess of the alkaline precipitant. In the cases of cobalt and cerium, the alkaline carbonate may be added in considera-, ble excess without separating any of those metals, and their solution so freed from iron is then @ most delicate test of the pre- sence of the latter metal. : ! April 12.—A pares was read, On the Mean Density of the Earth, by Dr. C. Hutton. | At the same meeting a paper was read, On the Restoration of a Portion of the Urethra in the Perineeum, by H. Earle, Esq. GEOLOGICAL SOCIETY, Feb. i16.—An introductory essay on the Geology of India, by H. T. Colebrooke, Esq. MGS. was read. | The physical geology of India may be considered as resolving itself into three great divisions; viz. 1. The peninsular tract, which constitutes the south of India; 2. The belt of flat country extending from sea to sea, and distinguished by the name of Middle India; 3. The continental mountains which form the northern limit of India, rising between the middle region and the vast extent of Tartary, and extending more than 15° of lon- gitude in a direction from WNW to ESE. In the champaign country constituting middle India, three principal divisions may be noticed; 1. The tract watered by the Ganges and its tributary streams; 2. A Tract watered by the Indus; and, 3. The intermediate desert, on which the Saraswaté loses itself. | | vectae Of this country, a striking feature is the total absence of pebble or rolled stones of any kind, except inthe beds of the rivers, for a few miles after they quit the hills ; and the subsoil of the plain is every where earthy and comminuted, except in certain. instances, where nodules, or concretions, have been found. Throughout this extensive plain, there is neither mine nor quarry: the banks of the river being usually precipitous on one side, and shelving on the other, exhibit sections of strata down _ to the level of their beds. Scarcely any other natural section is found ; and the sinking of wells, or bormg for water, is the only CRperneey which art presents for the examination of strata. he surface is every where alluvial, and the strata, as far as they have been observed, are horizontal. Beneath the superfi- ee iv the subsoil is sand, clay, or loam in layers more or less intermixed, and distinguished by colour or texture. In the inferior strata of clay, nodules or concretions of the same sub- stance are sometimes met with. The upper strata of siliceous sand, as well as that found in the-bed of the Ganges, generally . abound in fragments of mica; but in some places, beds of sand contaminated with salt, and in others, beds exclusively composed of salt, are found. | In a very few spots, and atno great depth below the surface, BO en aan, ee ~ 1821.] Geological Society. 391 nodules of a calcareous nature and irregular shape are met with, which, on calcination, afford an impure lime; but throughout the low country, limestone is génerally deficient. A sma‘l hill at Manihari, in North Bengal, being one of the few instances of detached hills.in the midst of this champaigne country, isa rock composed of rounded pebbles and angular nodules imbedded in a cement of like nature, but different colour. Both effervesce with acids, and the cement leaves the larger insoluble pro- portion. re In some places, at a considerable depth below the surface ; for instance, ‘at Calcutta, at the depth of 30 to 35 feet, fossil wood not petrified, but more’ or less rotten and decayed, is found, and sometimes in large blocks. Vegetable petrifactions. are also sometimes met with, and in particular’silicified wood. Except fragments of shells abounding in the fluviatile sand,) no animal exuvie have as yet been found within the limits of the low country of Middle India. ) March 2.—Part, of an “ Outline of the Geology of Russia,” by the Hon. W. 1. H. F. Strangways, MGS. was read. “eG Of the Russian empire, the two great divisions, viz. Russia, properly so called, and Siberia, must be considered in a geolo- gical point of view, as perfectly independent of each other, the same boundary dividing the two countries, and the two tracts of. secondary formation belonging to them. The empire contains © five principal mining districts ; viz. two in Europe, two in Asia, and one on the confines of Russia and Siberia. Those in Euro- pean Russia are the northern or Finnish district, and the central;) the former reaching from the gulf of Bothnia to the lake Onega;. the latter stretching across the country, in an oblique direction,. from the government of Kulouga to that of Nishegorod. The border, or Oural district, comprehends the Oural mountains as far as they have been explored. The two mining districts that lie entirely within the frontier of Siberia are those of Kolyvan, on. the west frontier of China, and Nerchinsk, on the.frontiers o China and Siberia towards the Pacific Ocean. . : | In traversing: Russia from north to south, we find a great extent of primitive country comprehending Russia, Lapland, Old and New Finland, the northern parts of Carelia, and part of - the government of Olonetz, and forming evidently a prolongation - of that of Sweden, with which its connection may be traced by the Isles of Aland, on the south by those in the centre of the Gulf of Bothnia, and by the Lapland chain of mountains on the north. Of this district, the northern parts are said to consist principally of trap rocks, the central of gneiss, and other varie- ties of schistose rocks; while the northern border is composed entirely of granite. Lhe The islands of Pargas in the Gulf of Bothnia, about two miles south of Abo, present in general the same features as the main land, being in fact but continuations of the hills of the continent, 392 . Proceedings of Philosophical Societies. [May, On one of the pore islands of this group, the mineral, known by the name o pangasites is found in one or more large veins of white primitive limestone which traverse the island from side to side, and which seem to bear some analogy with respect to their geological situation, and their external characters, to the lime- stone of the Hebrides, especially in the Isle of Tirey. The country through which this limestone passes is gneiss, the fissures of which are in a direction parallel to the course of the vein. The breadth ofthe vein varies from 20 to 100 feet. : ASTRONOMICAL SOCIETY. Apri 13.—A paper, from Mons. Nicollet, of the Royal Obser- vatory at Paris (communicated by the Foreign Secretary), was ~ read this evening: it contains his own calculations of the elements of the comet lately discovered by him in the Constella- tion Pegasus; theyare as follows, viz. . Perihelion passage, March 21...... 9° 33’ 7” Paris time Perihelion distance. .....-cceesc- 0:091113 Log. Perithel. dist, ».< +, o.:s:s.+-¢7 0.00, 8°9595327 - Longitude of ascending node. ...... Po aes ays + gg Longitude of perihelion (on the orbit) 239 18 37 Inclination of the orbit............ 74 10 53 Motion retrograde. A paper likewise.on the same subject, transmitted to the Society by Dr. Olbers, one of its associates, was read ; it con- tained the following elements calculated by Professor Encke, of Seeberg, by Professor Nicolai, of Manheim, and by Mons. Von Staudt, of Gottingen. ! Prof. Encke. Prof, Nicolai. M.. Von Staudt. Perihel. passage ..| Mar. 21. 405|/Mar. 21. 6016/Mar. 21, 6026 M.T. Seeberg.|M.T.Manheim|/M.T. Gotting. Long. of perihel.. [239° 20’ 45/239° 34’ 5”|239° 36’ 0” Log. etifiel dist..| 8°95966 8:96466 8°9641627 Long. ascend. node| 48 34 37 | 48 43 34/48 45 44 Inclination of orbit... 74 5 01} 73 23°15) 73 16 33. Motion retrograde. In this paper also allusion is made to the anomalous appear- ance lately observed on the moon’s disc, of which it will be remembered that an account was presented to the Royal Society by our countryman Capt. Kater.. The Doctor, however, differs from the British philosopher as to the cause of the phenomenon, and does not consider it voleanic. A Description of an improved megane Instrument, by George Dollond, FRS. and member of this Society, was then 1821.] Astronomical Society. 393. read. Its advantages over others’are obtained by applying a transverse axis to the telescope and declination circle, thereby giving them all the perfections of the transit instrument, without: diminishing their repeating properties ; and by the application of two levels alternately becoming finders to the telescope, which render the back semicircle unnecessary, a contrivance which saves much loss of time when repeating zenith distances. The instrument is also constructed to repeat in azimuth, and is fur- nished with a very delicate level, as a check upon the horizontal circle, and which answers all the purposes of an under telescope. The object glass of the telescope is of two inches diameter, and 17 inches focal length: with it the pole star may be distinctly observed in the day-time. The angles are read off to every tenth second by verniers and fixed microscopes. The instrument differs from all others previously made ; is furnished with every requisite for ascertaining vertical and horizontal angles, and which, if taken singly, may be, in the author’s opinion, as correctly obtained by this, as by any instrument of the same dimensions not possessing the repeating principle. , ArTICLE XIII. . SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS CONNECTED WITH SCIENCE. I. Purple Powder of Cassius. Dr. Clarke, of Cambridge, has recently examined the purple pow- der of Cassius ; and from his experiments, he concludes, that the binary compound which he analysed consisted of the oxides of tin and gold, and contained these oxides chemically combined in the exact propor- — tion of three parts of tin to one of gold; and that the alloy of the two metals obtained by the fusion of 100 parts of the purple powder would yield Metallic tin, ou. cgvedears pie eine 18 PRECIO OU iS se Lae & Bint ie 25 : 100 Because 8-10ths of a grain of the alloy yielded =~ Metallic tin. ...... ey or. ee Metallic gold...... 1 Dadeanepeesivg 5 & 0-2 0°8 Dr. Clarke also infers, that in precipitating the purple powder of Cassius from the muriate of gold, by means of the muriate of tin, the two metals, tinand gold, are thrown down as oxides, which, however, do not chemically combine in a constant relative proportion to each . other ; that the quantity of tin always exceeds that of the gold ; and that Scientific Intelligence. the difference observable in the hues of the:precipitate made at differ- ent times is to be ascribed to the different proportions in which the oxides of the two metals have combined together, and, perhaps, also: to their different degrees of pli Sd er of the spear Philosophical Society.) II. Quantity of Copper raised te Cornwall. In Six Months ending June 1819. The produce of 58 mines, 3327 tons ; of which, ty tons were pro- duced by six mines as under : ‘ United mines. ........ 5005 LOG ig wadraeis 4194, tons W.. Abraham, & ce... +. G496 1.) cosisewes 395 . DO COAL BG... « «.0.0+0:000-9 ~ 4704. sbetseribriecmsii 3454 Treskerby. ..,...+--- 2913 SUN HIS: 197 Wheal Squire. pain ae tid Ss So! aie, ae 1954 Crennis. ...... ap wah . 2407 oR cote py. FOO 22278 1736 Produce of the ore about 73 4 per cent. Price of copper, 1310. per ton. In Siz Months ending Dec. 18] 9. The produce of 74 mines, 3477 tons; of which, Bees tons were pro- . duced by six mines as under: Ore. Copper. United mines......... 3 Wt 482 tons W. Abraham, ......... TOR OSS Ts Oe 895 Doleoath ii». «ics. skrure: : SMOG i \ Sica « ain 375 Wheal Squire......... FO OR ems enn 188 Treskerby.. 00000 0. SEPOE. OELVEII RS WES Wheal Unity, &c.. -.... ROPSHH HS CHS 143 : 22873 1768 Produce of the ore about 72. per cent. Price of copper 124/, per ton. In Six Months ending June 1820. The produce of 66 mines, 3545 tons; of which, 1760 tons were Hro- duced by six mines as under: Ore. United mines Py Ph Fes 5798 tons... «2 0 <%s Dolcoaths :. ..0¢ ws +. 5438 BEE AB bay W. Abraham, Bites i), | GBR FS ROE OE Treskerby.-.......... 2206 9 cee Wheal Unity, &c....... OOS fe ieee ‘ Wheal Squire......... 1415 rie gurpeiee 21848 Bodies of the ore about 8 per cent. Price of copper, 114/, per ton. Copper. 511 tons 1821.] Scientific Intelligence. —ss BBB In Six Months ending Dec. 1820. The produce of 72 mines $962 tons, of which, 1891 tons were pro- - duced by six mines as under: Ore. Copper. ' United mimés. ......5. 5594 tons .....6.- 481 tons Dolcoath 32 S83 NGOS: ("> eeaultencck 403. Wheal Abraham, &c..- 5069 ~~ .......4. 388 regkerby i005 SU mnt OT pre: ft. Wheal Drewollas...... ZO74 , ‘so pa neato GOI 205 Pembrokeirig wieieis.s GGIE. oe ROE 201 : 93213 1891 Produce of the ore about 84 per cent. Price of copper, 113/. 10s. per ton. General Return of Copper raised in England and Ireland. One Year ending June 1819. . Tons. Cwt. Qrs. Cotnwatk, «.iadiaagd . iat 6974.2. 2 Angienen.' cerca. Cae a 564 60 0 Deven i. svn Wal osu 433. °;0 0O Ireland, Ecton, and other mines in Staffordshire . and elsewhere*.:..... 596 10 . 83 : $567. 13...1 One Year ending June 1820. Tons. Cwt. Qrs. Cornwall...... Si ADS GORE: “h.,/4%: Anglesea if. SN 561 0 0 Devo, 6 OU. ro GAY BR 414 O O \ Ireland, Ecton, and other mines in Staffordshire and elsewhere* ..... eee ae $7038: 15... 2 — III. Native Hydrate of Magnesia. The native hydrate of magnesia was first discovered, and ranked as a separate mineral, by the late Dr. Bruce, of New York. It was found only at Hoboken, in New Jersey, traversing serpentine in all directions - in veins of from a few lines to two inches in thickness. Dr. Hibbert found this substance in 1817 at Swinaness, in Unst, one of the Shetland Isles, traversing serpentine in all directions, being mixed with the magnesian carbonate of lime, and forming veins from half an inch to six or eight inches broad. : Chemical Character.—Hydrate of magnesia dissolves entirely in * Part of this quantity isfrom Cornwall; but from the mode of'sale, no exact division can be made. ye 396 Scientific Intelligence. [May, muriatic, nitric, and dilute sulphuric acids; and from its solution in muriatic and sulphuric acids, the deliquescent salt of muriate of mag- nesia and regular crystals of sulphate of magnesia were obtained. On some occasions, a very slight effervescence takes place; but this no doubt arises from adhering particles of carbonate of lime, or from a small quantity of carbonic acid, which may have been absorbed by exposure to the atmosphere. he following analysis of this mineral has been made by Dr. Fyfe : Magnesia... 05 Sad. ea OTE Waders, iid ie REN ei OEE 100-00 (Edinburgh Philosophical Journal.) IV. Results of Experiments, with a Magnetimeter invented by Mr. | Scoresby. 1. Iron bars become magnetical by position, excepting wher placed in the plane of the magnetic equator; the upper end, as regards the — of the magnetic equator, becoming a south pole, and the ower extremity.a north pole. . : 2. No attraction or repulsion appears between a magnetized needle and iron bars; the latter being free from permanent magnetism, whenever the iron is in the plane of the magnetic equator; conse- quently, by measuring the angle of no-attraction in a bar placed north and south, we discover the magnetic dip. 8. Before a magnet can attract iron, that is totally free from both permanent magnetism and that of position, it infuses into the iron a magnetism of contrary polarity to that of the attracting pole. 4. A bar of soft iron held in any position, except in the plane of the magnetic equator, may be rendered magnetical by a blow with a hammer, or other hard substance; in such cases, the magnetism of position seems to be fixed in it so as to give it a permanent polarity. 5. An iron bar, with permanent polarity, when placed any where in the plane of the magetic equator, may be deprived of its magnetism by a blow. 6. Iron is rendered magnetical if scowered or filed, bent or twisted, when in the position of the magnetic axis, or near this position; the upper end becoming a south pole, and the lower end a north pole; but the magnetism is destroyed by the same means, if the bar be held in the plane of the magnetic equator. | 7. Iron heated to redness, and quenched in water, in a vertical position, becomes magnetic; the upper end gaining south polarity, and the lower end north. ! 8. Hot iron receives,more magnetism of position than the same when cold, : 9. A bar-magnet, if hammered when in a vertical position, or in the position of the magnetic axis, has its power increased if the south pole 41 upward, and loses some of its magnetism if the north end be upward, ‘ 10. A bar of soft steel, without magnetic virtue, has its magnitude of position fixed in it by hammering it when ina vertical position; and 1821] . New Scientific Books. 397 loses its magnetism by being struck when in the plane of the magnetic equator. oy 11. An electrical discharge, made to pass through a bar .of iron, devoid of magnetism, when nearly in the position of the magnetic axis, renders the bar magnetic; the upper end becoming a south pole, and the lower end a north pole; but the discharge does not produce any polarity, if the iron be placed in the plane of the magnetic equa- tor. The effects appear to be the same, whether the discharge be made on the lower or upper end of ‘the bar, or whether it is passed longitu- dinally or transversely through the iron. ~ EB 12. A bar of iron possessing some magnetism has its polarity dimi- nished, destroyed, orinverted, ifanelectric discharge be passed through it,’ when it is nearly in the position of the magnetic axis, provided the south pole of the bar be downward, while its magnetism is weakened, or destroyed, if it receive the shock when in the plane of the magnetic equator. ; 13. Iron is rendered magnetical, if a stream of the electric fluid be passed through it, when it is ina position nearly corresponding with that of the magnetic axis ; but no effect is produced, when the iron is in the plane of the magnetic equator.—(Edinburgh Philosophical Journal.) V. Dissection of Crystals. M. Faraday found, that those specimens of sulphuret of antimony which are crystallized in large crystals, crossing each other, admirably illustrate Mr. Daniell’s mode of displaying crystalline texture by dis- section. On introducing such a piece of sulphuret into a portion of fused sulphuret, and continuing the heat, it begins to melt down; but so far from this taking place uniformly at the surface, crystals will sometimes be left more than half an inch long projecting from it; and in other places, the cavities left by fused crystals will be so large, and have such perfect surfaces, that the angles they form with each other may be readily ascertained. In order to observe these effects, it is only necessary to remove the half fused piece of sulphuret from its hot ’ bath, and allow it to cool.—(Institution Journal.) ) ARTICLE XIV. NEW SCIENTIFIC BOOKS PREPARING FOR PUBLICATION, Mr. Swainson is preparing for publication, Exotic Conchology, a Work to consist of coloured Plates of rare and nondescript Shells, 'A General History of Birds, by J. Latham, MD. &c. Author of the Synopsis of Birds, &c. 7 , The Fossils ofthe South Downs ; or Outlines of the Geology of the South Eastern Division of Sussex, by Gideon Mantell, FLS. JUST PUBLISHED. A Manual of the Diseases of the Human Eye, from the best National and Foreign Works; translated from the German of Dr. Weller, and 398 ; New Patents. [May, illustrated with Cases. By G. C. Monteath, MD. Illustrated by four highly coloured Plates, and one Plate + Instruments. 2 vols. 8vo. 14. 10s. Practical Observations on Midwifery. By John Ramsbottom, MD. Svo. Part I, 10s. 6d. The History of the Plague, as it lately appeared at Malta, Gory &e. By J. D. Tully, Esg. 8vo. A Practical Treatise on the Inflammatory, Organic, and Sijihpathe- - tie Diseases of the Heart; also.on Malformation, Aneurism, &c. By | Henry Reeder, MD. RMS. Edin. and MCS. Lond. The ninth Number of Ferussac’s ‘Natural History of Land and Freshwater Shells is just published. Useful Knowledge, or a Familiar Account of the various Produe- tions of Nature, Mineral, Vegetable, and Animal. By the Rev. W. Bingley, AM. Third Edit. 3 vols. 12mo. 1. 1s. , Transactions of the Cambridge Philosophical Society. © Vol. I. Part I. 4to. 1. Illustrations of the Linnean Genera of ‘Insects. By W. Wood, FRS. FLS. Part I. with 14 coloured Plates, 5s. to be completed in six monthly Parts. The Natural History System of Mineriless, By Frederick Mohs, Professor of ilps rang) 8vo. - 6s. 6d. ee ARTICLE XV. NEW PATENTS. Thomas Masterman, of Broad-street, Ratcliffe, common. brewer, for certain machinery for the purpose of imparting motion to be worked by steam and water, without either cylinder or piston, and with less loss of power than occurs in working any of the steam-engines now in use.—Feb. 10, 1821. Robert Stein, of Walcot-place, Lambeth, for certain improvements in steam-engines.—Feb. 20. James Foster, of Stourbridge, iron-master, for certain improvements in the manufacture of wrought malleable iron.—Feb. 20. Henry Penneck, of Penzance, MD, for an improvement, or im- provements, of machinery to lessen the consumption of fuel in working steam-engines.—Feb, 27. Robert Burton Cooper, of the Strand, London, for improvements on, or a substitute for, stoppers, covers, or lids, such as are used for bottles, tobacco, and snuff-boxes, ink-holders, and various other arti- “cles requiring stoppers, covers, or lids.~-March 3. _ - Jonathan Dickson, Holland-street, Blackfriars, for valuable improve- ‘ments in the means of transmitting heat, and. also in the means of transmitting cold from one body to another, whether solids or fluids.— “March 8. William Frederick Collard, of Tottenham-court-road, for certain improvements on musical instruments called piano-fortes.—March 8. - 1820.) Mr... Howard’s Meteorological Journal. 399 -ArticLe XVI. § METEOROLOGICAL TABLE. Barometer.) THERMOMETER, sel S > ae &. iS © pp 3 Hygr at 1821, | Wind. )Max.| Min.| Max. | Min. | 3d Mon. | . i , March 1S . E)29°88/20°44) . 48, 32 — 03| . 94 2S W 29'9029'82) 51 40 — | 26). 84 3S W)29°82/29°70| 52 45 ale | Enda dy: FOO 4S W/29°83)\29°70| 54 33 vos 31} 82 |@ 5N E/30°02/29°83) 35 30 sie 80 6S E 29°8929°63| 45 35 — 32| 88 7, W_ (|29°65,29°35|. 53 | 144 sie 22| 86 SN W/(29°65)29'32) 52 | 40 pare 13| $3 9 W 29°67|29°63| 54 47 _— 08; 76 10S Wi29:84)29°67; 58.) 40.0) — 05) 78 | ¢ 11S W/|29'97/29°84| 55 |" 33 — G73) 12 Var. {80 052997; 54 | 39 | “- | 03) 90] 13S W/{30°11/30°05| 56 36 56; Q3| 89 14° N -(30°38/30°11]'° 49°" | 24° . 76 N 15.N... E'30°38/30:30) 52 6 260} om 78 16] Var. |30°30)30 10) 53 24) — 80 17IN ° E/30°10/29°57| 55 | 37 | — | 12) 79 IRIN... .W)29'57|29°34) 49° |. 35 | | 27) 64 1 Q 19N W/29:36/29'31| 45° | 34 | — | —| 61 20IN W/{29'36/29'35) 47 oo. oe 58 (¢ QUN_ . W)29°71|29'36) . 46 D4, . dimen of oF 61 22IN W/{30°10|29°71| 47 26 — |— 64 23\iN’ - W/30°10/29'88} 47°} 35 |) — | | 64 24) S. . |29°85|29°47). 48.9} i42 | — | 20) 58 25S W/{29'68|29°47| 51 32 | — | 09 88 265. W}29:65|29'39}. 50-.|- 38 | —-} O7} 67 | y 27 W/29°39\2926, 48 | 33 | — |—| 62. 28/5 - “E'29°26/29°12} 58 | 41 | 55) 43] | 87” 29'8 W/)29'65}29°12| 47 | 34 | — |. 07|...86 305 “W)29°65|29'42} 50 36 — 10, 78 31/8 W)29°60|29°39] 51 | 32 20| 11) 86 s0-38l29-12] 58 | 24 | 1:86 | 29210058 The observations in each line of the table apply to a period of twenty-four hours, beginning at 9 A. M. on the day indicated in the first column. A dash denotes that the result ig included in the next following observation, 6... | ; } - 400 Mr. Howard’s Meteorological Journal. [May, 1821, REMARKS. Fhird Month.—}. Cloudy, . 2. Showery afternoon. 3, 4. Rainy. 5. Cloudy. : 6. Rainy. 7. Fine day: rainy evening. 8. Fine. 9. Showery. 10. Showery. 11, 12. Fine. 18, Fine morning: a slight shower of hail about noon; lunar halo in the evening. 14, Fine: lunar corona. 15, White frost: fine: a very distinct lunar halo, slightly coloured. 16, 17. Fine: white frosts in the morning, 18. Bois- terous: frequent showers of mingled hail, snow, and rain. 19. Windy: hail. 20. Windy: cold. 21. Cloudy. 22. Hail. 23, Fine. 24, 25. Showery. 26. Fine day: boisterous night.” 27. Boisterous. 28. Rainy: windy. 29. Showers. 30. Fine: rainat night. 31. Rainy. RESULTS. Winds: N, 1; NE, 3; SE,3; 8,1; SW, 12; W, 2; NW, 7; Var. 2. Barometer: Mean height For the month......sscsecvesesesseeseseseeseecsss 29°710 inches, For the lunar period, ending the 26th................ 29°765 For 14 days, ending the 4th (moon south). .......... 29-989 For. 14 days, ending the 15th (moon north) «.......... 29-866 Thermometer: Mean height : For the month... ..0.sscccscecesecccscccseecccevee 42°F58° For the lunar period... .4..00:++- in which a repre- sents the intensity of the central agitation, m the magnitude of the impelled atom, and 2 the distance of the centres of the two oodies. | When the attracted atom is not a sphere,} its law of gravita- tion becomes more complex ; and in a general way is not to be obtained in algebraic terms ; for it is dependant not only on the "intensity of the central agitation, the magnitude of the attracted atom, and its distance from the central one, but likewise on its figure and position. In all cases, however, when the attracted atom is exceedingly small and at any sensible distance, or when it is at a distance sufficiently great to render the influence of its magnitude insensible, its gravitating force will be as its magni- tude and the intensity of the central agitation directly, and the square of its distance inversely. Consequently, if instead of a single central particle, there were a great’ number distributed so as to form a uniform sphere, and in such a manner that the agitations of each may take effect, the force of the impulsion on the solitary atom, Principia, prop. 74, lib. 1, would be as = ; in which m is the mass of the attracted atom, A the agitat- * That no one may have to charge me with a desire of making innovations, I have retained the terms attraction, centripetal force, &c. though from the cause of the phe- nomena, as laid down in this memoir, probably impulsion, adpulsive force, &c. or some other words having a nearer affinity to the primitive cause, would be preferable. + The simplest case after a sphere is, perhaps, that of a cylinder, having the centre of agitation in its axis produced. Let B C be a cylinder, E F its axis, and A the centre of agitation. Draw AC, A D, and in A F take A G, A H, respectively equal to A C, AD; join C G, and complete the parallelogram I C. ‘Then will the gravitating force of. the whole cylinder towards A be as the rec- tangle of the . 54 at A, and the distance H I, _ But if the semidiameter E D be vastly small, compared to A E, the gra- vitation is as the agitation at A, and the magnitude of the cylin- er directly, and the rectangle A E, A F, inversely. ‘Therefore, if E F be likewise very small.in comparison of A E, the grayi- tation is directly as the agitation at A, and the magnitude of the cylinder, and hve as the square of its distance from A. — When the impelled body is a parallelopipedon, its gravitation — _ is as the logarithm of a function of its dimensions and distance . : A from the central particle, raised to a power equal to the intensity 0: agitation... And when it is so pis, abs at such a Mindnee from the centre, that its mh sees are insen- ‘#iblé in respect of that distance, its gravitation is proportional to its magnitude’ and the - intensity of the agitation direetly, and the square of therdistanceimyerselys; 4) O15 3.3 .1821.] Pheenomena of Heat, Gases, Gravitation, &c. 409 ing force of the whole central body, and w the distance between the centres of the atom and compound body. And since this is the law of gravitation of a single atom, it follows, by prop. 75, lib. J, Principia, if a number of them were equally distributed throughout any spherical space, so that they could be individually acted on by the fluid medium, the impelling force on the whole body would be as ring in which «x is the central distance of the ay? ? two bodies, and 6 the quantity of matter in the attracted body. For the same reason if B be the mass of the central body, and A’ the whole agitating force of the other, its attraction on the A'B a? central body will be as But the whole agitating force of a homogeneous spherical body, other things being the same, is as its temperature T, its numeratom N, and its volume V conjointly ; therefore, T being the temperature of the body B, its absolute TNV a? attractive force on 6 will be as f and its accelerative force ye aA zy” as And é, , v, representing the like things of the other body 0, its absolute attractive force on B will be as ae, and ° : tnv its accelerative as —-. Now Newton has shown, p. 242, of his Optics, bodies to be so rare that water has at least 40 times more pores than solid parts ; and Biot, in his Traité de Physique, tom. iv. pp. 124, 125, has carried the idea so far, as even to suppose the solar system itself to be but one great particle relatively to other larger and rarersystems. Without inquiring into the merits and probability of this bold idea, there is every reason to believe with him, that ‘‘ il se pourrait méme qui dans les corps qui nous paraissent les plus denses, la capacité des interstices surpassat plusieurs milliers des fois le volume des particules matérielles ;” or, at least, that the densest bodies we know of do indeed con- tain vastly more pores than solid parts. Therefore, it follows, that every one of the particles of any compound body might agitate and produce those affections I have imagined on the ethereal fluid, very nearly the same as if it was alone and unsur- rounded by the other particles ; and conversely, the particles of any compound body might be individually affected by the agita- tions of the medium, almost the same as if they were alone. Before 1 proceed further, it is necessary to anticipate an - objection that at the outset might be made to this theory of gra- »witation. The force of gravitation that has been here determined is on the supposition that the impelled body is in a ‘state of quiescence ; and it, might, therefore, be conceived, that. the ‘attraction would be less on a body moving towards the central _ body, and, greater on one; moying from,it, which.is contrary to 410 Mr. Herapath onthe Causes, Laws,and:principal [June, what we find by experience. Though regarded mathematically such an inference would be strictly true, yet since the difference between the forces will depend on the activity of the medium, and since this activity will be imereased in proportion to the _ tenuity of the parts of the medium, it is evident that the ethereal atoms may be so small, and the activity of the medium conse- quently so great, that the swiftest motions we know of could ‘produce no sensible difference in the Vigour of its action. For instance, suppose one of the ethereal atoms to have the same ratio to. a particle of light, that,a ball, a foot diameter, has'tothe whole earth (and there is certainly nothing which forbids us ‘to suppose that the ratio might not be:as little or even much less), “then calling the earth 42000000 feet diameter, a thousand of these ethereal atoms would, individually, with the same force that. gives motion to a particle of light, receive a velocity more than 74000000000000000000, times. greater than that. of light. But with such an activity, the law of attraction on a body moy- “ing with the velocity of light, in ‘the direction of the attraction, 54 | -would not be augmented more than .a s555559900000000000000 “4 art of unity. And with this increase in the law of attraction, “it would be 2857796067672610 years before the apses of the earth’s orbit would move one second of a degree. But since our calculation is made on the supposition that the body with- draws itself, as it were, from the action of the impelling power »with the rapidity of light, the augmentation or diminution of the law on a body, moving like any of the bodies of our planetary ~system, would be many million times less ; and, therefore, it - would take many million times the period that I have assigned to produce, with a fluid of such activity, a difference of 1” inthe position of the earth’s apses. We may hence fairly conclude, that there might be a fluid medium pervading the heavens ‘and all bodies of such activity, that no sensible difference could be observed in the intensity of its action on bodies in a state of quiescence, or moving with a velocity, not only six million,* but several million million times greater than that of light. With the same views it-would be easy to show ‘that the resist- “ance which such an ethereal fluid:would cause ‘to the motions of any of the celestial bodies, could produce no:sensible effects in a period of many million years. No objection, therefore, so faras -it respects resistance or irregularity of law of action, can be made to fillmg the heavens with a fluid of this kind, which it would not be easy'to answer; and we might: consequently infer, ‘that -whatever has been demonstrated of an:unresisting anda So meating gravitation, might ‘be easily transferred to our fiuid jomedionns 1ii.4) yhod beoteaal ot) Jadi coiseoga -Dhekeeings being grated i lows, that Koes i th —~ .1821.] | Phenomena of Heat, Gases, Gravitation, &c. o4)1 «expression for the law. of gravitation towards any spherical bedy, the gravitating forces, or the weights of any two spherical -bodies towards,any other body at equal distances, are as)the quantities of matter in the attracted bodies, This law has been proved experimentally by Sir Isaac Newton; but though this. be true, the converse case; does not, according to our principles, shold. good; namely, that the attractive forces of bodies \are directly proportional to their quantities of matter.|| Our princi- ples, do. not, therefore, corroborate Newton’s'third law of motion, respecting the equality of action and reaction in) attracting forces; for by our theory a body might, by the agency, of) the fluid: medium, be impelled towards another without any recipro- cal, action, which is by no|means) surprising, if we consider -attraction/not to be an inherent; or essential property, of matter, “but merely the action of a third body. “When, however, we take shomogeneous* bodies of the:same temperature, the equality of action and reaction seems to hold true; but in different bodies, differently composed, or the same body at different. temperatures, a difference should be observed in their attractive forces propor- tional to the greatness of the dissimilarity. Other things being alike, the attractive forces should: be proportional to the temper- vatures.; so that the attraction of all bodies at the extreme tem- peratures of the fluidity of water, should. have a ratio of about 6 to 7. Unfortunately the difficulties attending the corroborat- ing by experiment of this. part of our formula, much, exceed those.of the other; nor have 1 as yet devised any method.of satisfying myself respecting it in the manner that.L could wish, -But though great difficulties lie in the way of a numerical) proof, there are some phenomena which seem. pretty. decisively to sanction the general result:of.our formula ; namely, that. an increase of temperature produces an augmentation of attraction. Thus Euler has found that the focus of a convex lens is con- ‘tracted by a greater and. extended by a less temperature ; from which it plainly appears, thatthe refracting force is increased in the one and diminished in the othercase. .M. Laplace in the Méca- nique Céleste has calculated the annual equation of the moon at Al’ 22”, while, by the best tables, it is only about 11’ 81’. The difference between these quantities appears too. much for the error of either observation or calculation, and therefore indi- cates an increased attraction in the perihelion, and a decreased an. the aphelion earth... By all the: calculations that have hitherto been made, \a. regular/diminution in the attractive forces of the planets, reckoning from the sun, has been observed, which shows that»the' colder’ planets liave “less «attraction than the . * By homogeneous solid or fluid bodies is“here meant those ‘all of whose parts*are ‘similar, both with respect to their constituent elements and the’ association of them. \ “> Since writing this, I have contrived’a method, by a modification of Mr.Cayendish’s _ — ‘put haye not yet met with a proper place’and opportunity for putting it in practice, chustitel woo x useisqiist vision aatewisd aC yd fevin viots -412 Mr. Herapath on the Causes, Laws, and principal [June, -warmer. Uranus alone, if future computations should verify the present, exhibits an exception to this rule. This is not indeed impossible, nor repugnant to our formula; it only requires a dif- ferent constitution from the rest of the planets, such, for instance, as minuter particles ; for then by reason of the coldness, they may be more numerous. Another argument in favour of our formula is the very small disposition to disturb that is found in comets.* This might in part arise from a difference of consti- tution, but it hardly seems reasonable to make it the only cause with ail of them. Granting that attraction and temperature are proportional, it follows that the polar parts of the earth being colder than the equatorial, the attraction of the whole earth, in places about the former, must be less than its attraction in places about the latter; and, therefore, the isochronal pendulum must be shorter under the poles than at the equator. bn this account, therefore, if the earth was a sphere, its figure, as indicated by the pendulum, should be a prolate spheroid; and if the figure be an oblate spheroid, the measures by the pendulum would give either ‘a -prolate spheroid, a sphere, or an oblate spheroid of less eccen- tricity than it really is. Now, according to the best observa- ‘tions, the compression of the earth by the pendulum is about ), | i 957111 LO It has now been presented to the Royal Society by Davies: Gilbert, Esq. MP. VPRS. &c. who ‘received it from my hands. : lam, Sir, your obedient humble servant, 0.» . TOL OLGO . H.S. Trimmer. Articie II. Analysis of Verdigris. By R. Phillips, FRSE. &c. Havine lately had occasion to make some. inquiry into the different methods of preparing acetic acid, my attention was of course particularly directed to acetate of copper, as one of the substances\ from, which it has. been often procured. . Upon referring to. the more recent chemical.authors to ascertain its composition, I could not find that any analysis, of it had, been. made since that given by Proust, according to which crystallized acetate of copper consists of Acetic acid and water... .0..ssceeeee. G1 Peroxide of copper. .........- Seeccesie OO 100 From this statement, it is not possible to learn the quantity of real acid contained in the salt; 1 made, therefore, some experi- ments to determine this point. Acetic acid does not form with any substance a sufficiently insoluble compound to enable us to determine its equivalent with precision, nor can the whole of it be obtained by distillation ; I adopted as a substitute the following method: One hundred grains of crystallized acetate of copper were dissolved in distilled water ; excess of hydrate of lime was _ added to the solution, and the mixture boiled. The oxide of New Series, vou. t. ‘2D 418 Mr. R. Phillips’s Analysis of Verdigris.” (June, copper precipitated, and the undissolved lime, were separated. by the filter; through the clear solution, containing excess of lime, I passed a current of carbonic acid until the lime was precipitated, and I then heated the solution to separate any carbonate of lime which might have been redissolved by the carbonic acid. Having filtered the solution, J found it to be’ neutral acetate of lime, and then decomposed it with carbonate of soda, which gave 48°5 grs, of carbonate of lime; On repeat- ing the experiment, I obtained 48-6 grs. the mean being 48:55.. One hundred grains of crystallized’ acetate of copper were dis- solved in water, and boiled with excess of potash. Renieronide of copper precipitated, weighed, after washing and drying, 38-9, rs. On repetition I procured .39°5 grs. giving a mean of _ According to’ Dr. Thomson, an atom of acetic acid weighs 63-75; and [ am satisfied, from various experiments, that: it: is very nearly correct ; and if we consider this acid to be composed, of three atoms of hydrogen, three of oxygen, and four of carbon, as is generally admitted, it will bé represented by 63:96 on Dr. Wollaston’s scale, agreeing almost precisely with Dr. Thomson’s) determination. If then 63. of: fo dato of lime, the number representing it on. the scale, give 63°96 for acetic acid, 48°55 the carbonate of lime resulting, as above described, from the treat- ment of 100 grs. of acetate of copper, will indicate 49-2 of acetic acid ; so that we may consider crystallized acetate of copper as composed of srs bien _. Acetic;acid eRe ewe ewe dios Heweeeesens 49-2 ef cotiness vidlt QUORALG. O28 CODER... 0:0 45m «bob chiens mnt Po AF OFC Leaymg for water Y.94 EOHTOR BPE . T1-6 ; ity Bi ; } é ; OB OTT SC I ee } ort Te iy 10 etejees 0} heisotib yi DOs: (QD “Tf, as is generally admitted, peroxide of copper bea ge ey 1 of ‘two atoms: of. oxygen 20, and one’ atom of ‘copper 80; the atomic constitution of verdigris will’ be:°° °° | | 7 ». By-theory, . By.experiment.... 2 atoms of acetic acid. ........ 127°92 ..... 128°84 1 atom.of peroxide of copper. ...100°00 ..,. 102-65 3 atoms Of Water. vo seccecccce GS90 seve DU'SD ' Cehle 26188 261°88 . _ Dr. Thomson has lately shown, that the salt. called blue vitriol is a bisulphate of copper; and in addition to the reasons. which he has assigned for ths opinion, I may .add.that if finely divided. carbonate of lime be added to a solution of, it, insoluble sulphate, of copper is precipitated with effervescence, and as,.the same, effects are produced with the soluble nitrate and muriate of cop-. per, and with the acetate also, although very slowly, I think we may conclude, that the soluble nitrate and muriate, as well as, the sulphate and acetate, are bisalts. | : ; 1821.) Di. Clarke upon thé Gas Blowpipe. : 419 Articte III. Observations upon the Gas Blowpipe, and upon some of the moré remarkable Resulis which have been obtained in using this Instrument during a Course of Five Years, in which it has been constantly employed; being a Continuation of former Remarks upon the same Subject.* By Edward Daniel Clarke, LLD. Professor of Mineralogy. in the University of Cambridge ; Member of the Royal Academy of Sciences at Berlin, &c. Kc. (To the Editor of the Annals of Philosophy.) SIR, | Cambridge, May 12, 1821; _ A pErRtop of five years has now elapsed since I first began a course of experiments with the gas blowpipe. In all this time those experiments have been of a public nature. Upwards of 100 persons were present, March 15 of the present year, when the metallic base of barytes was revived and exhibited. It had been cut by a file in three places ; and it presented such a high degree of metallic lustre that it seemed as if the points of threé iron nails had been similarly acted upon by the file. This metallic body being then left covered only by a glass vessel, speedily became oxided, and fell into a white pulverulent earth | of barytes. In this experiment, no oil had been used to mix with the barytic earth for the purpose of making its particles adhere ; it was taken from a glass vessel in a compact state; as it had been prepared with the utmost care by Messrs. Allen, chemists, of London ; and was exposed, per se, to the flame of the gas blowpipe, supported in a pair of forceps, the points of which were made of slate. The reasons which have given risé to the opinion that the metallic substance thus ‘so often exhi- bited, is, in fact, the metal of barytes, are simply its property of rapidly decomposing water and atmospheric air; added to the perfect metallic lustre which it discloses to the action of a file, or other sharp instrument. In addition to which may also be mentioned the appearance which it exhibits prior to its being cut. It has then a highly metallic surface resembling the stalactites of the black oxide of manganese ; but of a jet-black | shining colour, with occasional metalline particles, disposed in‘a dendritic crystallization upon the dark surface. If, hereafter; chemists should determine that these characters are not of themselves sufficiently decisive as to its metallic nature, still the name of plutonium, which, in a former communication, F ven- tured:to give to this appearance, may be considered as useful for its distinction, because, whatever be its. real nature, itis a * See Annals of Philosophy, x.373, xiv. 143, &e. > 4g + So a | 420 Dr, Clarke upon the Gas Blowpipe. [June; result of fusion possessing properties of a peculiar nature. It differs from wood-tin, which exhibits, after fusion, the same degree of metallic lustre, but is still in the state of an ovide. Being guided by no other views thart those which may con- duce to the interests of science and the advancement of truth, after once more calling the attention of your readers to a subject. not unworthy of their regard, it is my inten- tion to consign to ‘them its future and further consideration; briefly adding what, in the course of the last five years of expe- rience, I have discovered to, be. the cause of failure in the attempts made for obtaining this effect of fusion in barytes ; and moreover a few remarks upon: some other curious pddbiiena which the use. of the gas blowpipe has developed. 3 In the first accounts which F Sapushed of experiments with this blowpipe, the propriety of mixing the oxygen and hydrogen gases in the’ exact proportion for forming water was always insisted upon ; because, when. the hydrogen gas is only added in _ slight excess, the mixture either will not burn at all, or the tem- . perature of the flame is greatly diminished ; upon the elevation of which temperature the success of many experiments depends. There are some experiments for which only Aydrogen gas alone may be conplloy et combined with a small portion of atmospheric air; or hydrogen gas uncombined with any other aeriform fluid ; but the temperature is then greatly lowered; and hence may be perceived the impropriety of naming this instrument the oxry-hydrogen blowpipe; because it is adapted to gases of kinds ; whether in a state of explosive mixture: or not ;.some being used, as, for example, oxygen gas, not forcombustion, but merely as.a supporter of combustion, to propel the flame of a combustible body, as alcohol. It is on this account that I have preferred calling it the gas blowpipe; being an appellation. of a more general nature; applicable, not only to the use which I have made of it in. burning the gaseous constituents of water, but to all its operations with condensed gases of whatsoever nature they may be. But to return: I have since found that for communicating the utmost elevation of temperature to the flame of mixed. oxygen and hydrogen gases, it is better to add the hydrogen gas in greater excess than was at first thought to be neces- sary : instead of two parts by bulk of hydrogen to one of oxygen, the proportion of nine to four is greatly to be preferred ; as, for - example, nine pints, or measures, of hydrogen gas, to four pints, or measures, of oxygen gas.* ‘The operator upon opening the valve, to set fire to this mixture, will immediately perceive how, much more explosive it is than any other; by the rapid snap- ping noise of the flame, caused by successive detonations at the mouth of the jet, while he is lighting the gas with a paper, and * This proportion ought especially to be observed when the oxygen gay has been obtained from the oxide of manganese, and the hydrogen gas from the decomposition of water by iron filings acted upon by sulphuric acid. . / .821.] Dr. Clarke upon the'Gas Blowpipe. 424 which is an infallible sign of the excellence of his gaseous mix+ ture forall experiments when the highest temperature is required.’ The stoutest platinum wire will run: before it into rapid fusion, and is immediately exposed to combustion. Pure magnesia may - thus ‘be easily fused, and be made to form a frit, which cuts glass like a diamond. ‘The edges of Iceland spar, that most refractory of all bodies, when exposed in thin lamine, are by’ the flame of this mixture invested with a white opaque avail. Rubies and sapphires become liquid, and flow together into one boiling mass. Grains of zrzdium melt and burn like platinum. Under these circumstances, if the earth of barytes be now exposed to the powerful heat of the burning gaseous mixture, unless the valve be partially opened, so as to allow a very small body of flame, like the point of a fine needle, to act upon it, it will be converted into a greenish glass, or into a substance exter- nally resembling horn, disclosing no metallic lustre to the action of the file. In my first experiment this year for exhibiting the metallic base of barytes, the attempt entirely failed ; but 1 was thereby guided, for the first time, to the cause of the failure ; for the barytes which failed was taken out of the same bottle as that which afterwards exhibited, in so imminent a degree, the metallic lustre 1 have already described. The cause was owing to the length of time in which fusion had been going on, and the too powerful heat to which the revived metal had been exposed: it came away altogether in white fumes, settling upon the forceps, and tinging the flame with that olive-green colour which always characterizes the combustion of the metallic base of barytes. ‘The same would happen with silver ; the whole of the metal would be dissipated in white fumes, which would settle upon the supporter if the heat be continued «long enough, and the flame also is in this experiment tinged of a paler greenish hue. For exhibiting, therefore, the metallic lustre of plutonium, call it a metai, or a protoxvide, or by whatsoever other name chemists may hereafter decide, it is necessary that the experiment should . be conducted with care. The barytic earth should be, in the first place, rendered as perfectly an anhydraie as possible ; the presence of an atom of water would inevitably cause the experi- ment: to fail. Of course it is hardly necessary to add, that water ought by no means to:be used as a substitute for oil in the safety cylinder; for this would again give rise to failure. _ Having a'small cake of the hard anhydrate of barytes, supported by a pair of forceps, allow the flame gradually to act upon it, until it exhibits after fusion the deep jet-black substance I have before alluded to. Then while it is hot, rub one of the promi- nent points of this black substance upon the sharpest and finest file, previously made warm before the fire, taking care not to cut it too deep, because that would disclose the barytic earth yet remaining below the part which has been fused. - The metallic 422 Dr. Clarke upon the Gas Blowpipe. (Jung; lustre ought to.equal that which is presented after filing the end of a piece of iron wire, or the experiment has failed. ith It #6 always failed when the fused barytes leaves traces of a white powder upon the file, : : _ It has, moreover, always failed when the fused. mags exhibits the slightest degree of translucency ; or is' of a grey, greenish, or white colour. It has always failed when the experiment has been protracted beyond the point at which the metal begins to burn, and is dissi- pated in white fumes. To all those gentlemen who have so often witnessed the per- fect metallic appearance of the melted barytes in my lecture room at Cambridge, I may now appeal for the truth of the result; being very anxious that others should also witness the same appearance, to whose testimony it may never be in my power to appeal. It would be to no purpose enumerating the names of those who have been present with me during my experiments ; pereine not only of this University, but from yarious parts of the kingdom, visiting Cambridge, have satisfied themselves in this respect. Upon Apri/ 10, 1819, there were resent for this purpose from London, Mr. W. Hamilton, Under ecretary of State; our Envoy to Constantinople; Mr. B. Frere; his brother Mr. Serjeant Frere, Master of Downing College ; Mr. Meyer, Consul at Corfu; Mr. Mackenzie, of the Foreign Office ; and also Colonel Leakes, of the Artillery; all of whom, independently of those whose residence here, gives them more frequent opportunities of being present at these experiments, are able to youch for the truth of the statement I have made. But so lately as the 25th of Apri/, of the present year, Prof, Miuiller, of Copenhagen, together with several gentlemen of this University, were present at a series of experiments conducted with the gas blowpipe, and all of them witnessed the revival of the metal of barytes by means of this instrument. The experi- ment was conducted as before described; and was repeated in their presence always with the same result. Prof. Muller took away with him a specimen of the metal so revived; but which of course would speedily afterwards be again converted. into the state of an oxide. It is sufficient, however, to observe, that they all saw it in the metallic state. If, therefore, the experi- ments elsewhere should not be attended with the same results, the circumstance must admit of this obvious inference; that the means resorted to, and the manner of using the instrument, have not been made adequate to the end proposed, which other- wise might have been accomplished. The other chemical changes which bodies undergo when exposed to the full powers of the gas blowpipe, and which appear to me to be of a nature sufficiently remarkable to merit the attention of chemists, are as follow: 1821,] Dr, Clarke upon the Gas Blowpipe. 423, 1. Rock crystal, or any other highly refractory seliceous . or aluminous substance, being allowed to fall upon a deal board, while infusion, and there left to become cool, exhibits upon the surface that came into contact with the wood, where it forms a charcoal cavity, a metallic lustre, equal to that of polished silver, This metallic appearance may be preserved for any length of time unaltered. Some of the students in this Univer- sity have preserved specimens of melted rock erystal thus invested by a seeming metallic body, the nature of which is unknown. | . 2. White opaque quartz melted in the flame of the gas blowpipe becomes so highly limpid and transparent, that after fusion it has all the appearance of rock crystal, The Plutonists may, perhaps, hence infer, that the transparency of rock crystal 1s owing to the heat it has sustained. _ 8. The varied and striking colours of metallic oxides are surprizingly developed by the flame of this blowpipe. Among these, one of the most striking from its beauty is the intense red, or bright purple, colour of the oxide of saitea, as displayed during the fusion of Iceland spar. It is a colour which cannot easily be described ; being much more vivid and striking than “the colour which the oxide of strontium.communicates to the same flame, and of a livelier hue. Add also the beautiful rosy colour of the oxide of gold, after its combustion upon pipe-clay ; the deeper purple hue of the compound oxides of gold and tin, when the alloy obtained from the precipitate of casstus has simi- larly aad combustion, the green colour of the oxide of rho- dium, &c. &c. ve 4, The gaseous fluid which escapes during the fusion of pure silica, has never been collected, and, of course, remains unknown. 6. The dark porate dispersed during the combustion of platz- num requires further examination. From some experiments made with this. substance, of which I before published an account,* it seems to be the protoxide of the metal. _ 6. The dark sooty-looking powder that remains after the solu- tion of crude platina in nitromuriatic acid, divested of all metal- lic particles which may remain undissolved, and consisting essentially of the oxides of iridium and osmium, is one of the most refractory substances that have been exposed to the gas blowpipe. By making a filter which was. invested with this powder into a pellet, and exposing it upon.charcoal to the full power of the flame, I succeeded in melting it into a brittle metallic mass. mixed with a.deep blue glass, which had resulted from the silicated alkali contained in the paper of the filter, as in all vegetable bodies. It was not rendered malleable. The surface of the charcoal during this experiment was covered with an oxide of a dark lilac purpie hue. * See Annals of Philosophy. 424 Dr. Clarke upon the Gas Blowpipe. (Jung, -’7. The beautiful iridescent crystals which form in the aqueous solution of the muriates obtained by dissolving crude platina in nitromuriatic acid; and after the precipitation of platinum by murtate of ammonia, are easily reduced to the metallic state upon charcoal by the flame of the gas blowpipe.: The metal so obtained is perfectly malleable, and has all the characters of platinum; excepting that it is almost insoluble in nitromuriatic acid, even when this acid is in a boiling state; owing, probably, to a small portion of iridium with which the platinum is conta- minated. 8. The prussiate of palladium obtained by the precipitation of this metal by prussiate of mercury, may be decomposed, and the pure palladium revived upon charcoal, with all the whiteness of silver, and made perfectly malleable. This last experiment with the gas blowpipe is remarkable for the beautiful sapphire-blue colour with which the flame is tinged during the revival of the palladium. Itaffords, moreover, one of the easiest processes for obtaining small specimens of pure palladium to which the che- mist can have recourse. All that is necessary is briefly this : Dissolve crude platina in nitromuriatic acid ; evaporate to dry- ness ; add distilled water; precipitate the platinum by muriate of ammonia ; filter the supernatant solution ; shi ters prussiate of palladium by prussiate of esgic and collect the precipitate upon a filter. Now make this filter containing the precipi- tate into a pellet, and expose it upon charcoal to the flame of the gas seen’ The result will be a malleable bead of the purest palladium, coated over with blue glass from the st/icated alkal of the paper filter, which separates from the metal upon the first blow of ahammer. Glass will also appear in all experi- ments for the revival of metals where filters have been thus used. It is, perhaps, a-similar result to the glass which remains after the combustion of bank-paper notes. | 9. The revival of the salts and oxides of the four metals obtained from arenaceous platinum; namely, iridium, osmium, palladium, and rhodium, whether as alloys, or as pure metals, afford some of the most curious and amusing experiments with the gas blowpipe. ‘The last experiment with these metals which I shall now describe relates to the revival of rhodium from its oxide, as obtained in the following manner: After the solu- tion ‘of crude platina in nitromuriatic acid, having preci- pitated platinum by muriate of ammonia, and palladium by prussiate of mercury ; also tron by prussiate of potass, immerse a clean plate of zznc into the filtered liquor, and leave it for several hours. A precipitate will fall of & brnetisbred colour, which, when dry, is black. Before the gas blowpipe, the filter, ¢on- taining this precipitate, exhibits a sort of coruscation, like a little firework ; but at length: a slag will remain ‘on the charcoal of an iron-brown colour, containing within it a bead of a-silvery- white metal. This metal is harder than wrought iron, It was 1821.) -Dr. Clarke upon the Gas Blowpipe. 495 also brittle, I endeavoured to dissolve the slag containing it b} boiling it in caustic potass, but could not succeed. Afterwards I added nitromuriatic: acid, and having evaporated the acid to dryness, there remained a rose-coloured salt. Still the bead of metal remained chiefly undissolved. I then. fused it with su/- phur, and expelled the sulphur on charcoal by the common blow- pipe. Still the metal was brittle. I then tried to cupel it upon ipe-clay with borax; it was.infusible; but it communicated a Sieh, and afterwards a black colour to the borax ; which are the hues of the deutoxide and protoxide of rhodium.. The metal also in these experiments always became black by heat; which is another character of rhodium. By mixing theater dry caustic potass and borax, in equal parts, | found I could hold it in perfect fusion upon charcoal before the common blowpipe, and distinctly discern the minute globules of metal separating in the boiling flux. Still the result, when cold, was brittle, and quite black. 1 then boiled it again in nitromuriatic acid, and by eva- oration to dryness had a beautiful rosy muriate. Afterwards I added the acid once more, in a dilute state, with common salt. The rosy soda muriate appeared as it became dry. I washed the residue repeatedly. with alcohol, and dried it. Distilled water was then added, and the solution, by gentle heat, being evapo- rated to dryness, the rosy-coloured soda-muriate appeared as before; but in less quantity. These experiments were con- ducted upon a bead of metallic rhodium, revived from its oxide before the gas blowpipe, the weight of which originally could hardly have equalled 1-10th ofa grain. When the oxide has been obtained in greater quantity, nothing more is necessary for its revival, than to mix it with oz, and expose it upon charcoal before the flame, which should be made to act vertically upon the oxide by means of a bent tube. | The. experiment is beautiful, owing to its simplicity, to the facility with which it may be conducted, and to the curious result which follows it; namely, the revival of metallic rhodium, exhibiting all the whiteness and lustre of the purest silver, and being perfectly ‘malleable. This experiment was attended with more than usual success on Saturday, May 12, when it was ublicly performed in my lecture room in Cambridge. The lack oxide of rhodium, precipitated from its solution by zznc, was mixed in the form of powder with oz/, and exposed, upon charcoal, to the flame of the gas blowpipe. It was first melted into a black slag ; then into a brittle white regulus, which, by continuance of the heat, became a bead of metal as white as the purest silver. It then began to burn, like platinum, with scin- tillation ; and the flame of the burning metal was tinged with a fine emerald-green colour ; proving that one of the oxides of rhodium may have the same hue. The bead of metal was then placed upon an anvil, where it sustained the shocks of a large ammer ; and was finally extended and flattened in its form. It 426 Dr, Prout’s Reply to Dr, Yellaly. [Junz, is, therefore, evident that rhodium may be rolled and made into foil like platinum. But there is onecurious circumstance which will render it always brittle, Ifa quantity of the soda-muriate be mixed with the b/ack oxide, a regulus may be reyived ; but no degree of heat, nor any Repalann of fusion, will render it malleable. A portion of it will then always be converted into slass, and-it will exhibit a granular texture, depriving it of mal- eability. Nor is the soda-muriate itself so likely Sen revived in a malleable state as the black owide of the metal, which never S. 10. The hard carbonate of magnesia from the East Indies, described by Dr. Henry, in a late number of the Annals of Phi- losophy, fused before the gas blowpipe into a white enamel, com- municates a purple colour to the flame, 11. A remarkable difference may be observed in the fusion of the several crystallized and amorphous varieties of the phosphates of lime. Some, like the white opaque apatite, from Devonshire, fusing into a jet-black gloss which is magnetic; others, as the conchoidal apatite of Modum,in Norway, and the earthy apatite of Estremadoura, fusing into greenish and limpid glasses, which have no magnetic properties. itis To conclude all these observations upon the gas blowpipe, it will be useful to some of your readers to be informed of the best method of preserving the bladders employed for containing the gaseous mixture; because it is difficult to meet with very large bladders, and they are soon rendered unfit for use, without the following precaution. Let them be kept carefully rubbed oyer with oil, and distended with common air, when not wanted. for experiments. By attending to this mode of preserving them, we haye found that the same bladder may be made to last in constant use for the gas blowpipe, upwards of two years, without. becoming porous, which so frequently happens where the oil has not been applied, in consequence of the attacks of insects, Epwarp Danten CLarke. Articre IV.. Reply to Dr. Yelloly’s Remarks on the Estimate of Mortality JSrom the Operation of Lithotomy. By W. Prout, MD. FRS.- (To the Editor of the Annals of Philosophy.) DEAR SIR, _ May 9, 1821, In reply to Dr. Yelloly’s remarks on my estimate of morta- lity from the operation of lithotomy in your last number, | beg leave to observe that the adoption of the. ratio alluded to is. not the result of inadvertency, but design., My object.is to give.a Vv ‘ 1821.] Dr, Prout’s Reply to Dr. Yelloly. 427 mean which, in the present improved state of surgery-shall tole- rably well:serve for the whole ingaom The data we. possess are obviously too imperfect to admit of this being done with much precision, and the ratio actually deducible from them (viz. 1 in about 61) seems, when all the circumstances are duly con- sidered, to exceed the truth. On the other hand, the ratio deducible on general principles from the same data, though of course not necessarily more correct than the actual one, hap- pens to coincide more nearly with my views; hence (and as I am also reasoning generally), I give it the preference.* The circumstance which renders the data in question particu- larly defective is their not including the metropolis, where, according to Mr. Smith’s estimate, two-fifths ofthe whole num- er of operations in the kingdom are performed. We have no means of obtaining correct information on this point, which is much to be regretted, but when we take into account the acknowledged skill of our surgeons, and the fact that nearly one-half of the above proportion of cases are private, in which of course every circumstance that united extraordinary skill and attention can devise to ensure success is attended to, we cannot hesitate, I think, to draw the conclusion, that the rate of morta- lity is as favourable, if not more so, in London, as in any part of the country. This circumstance, if admitted, will aa to diminish considerably the general ratio of mortality; perhaps, reduce it to .l in 7, or upwards, even according to the usual mode of estimation by taking the average of a number of past years. But this mode of estimation is not exactly applicable to my purpose. I wish to represent the rate of mortality as it exists at this time, when I am willing to believe the surgical art is more perfect than'at any former period: this, if admitted, will allow a still further reduction in the rate of mortality ; so that upon the whole, I trust the ratio given does not much exceed the truth; - and if it does, 1 acknowledge that I feel much less regret in fall- ing into an error on this side of the question than the other.+} Such are the principal reasons which induce me to prefer the © general ratio I have given to that actually resulting from my imperfect data. 1 donot mean to assert that they are absolutely conclusive, but, on the contrary, willingly admit that there is room for diversity of opinion on the subject. Every one, there- fore, must decide for himself. 7 * Means, generally speaking, -are correct in proportion to the number of observa- tions. Thus, from the multiplied observations of the Bristol data, the mean deduced on general principles differs very little from the actual mean, though both are evidently very far below the general mean as applicable to the whole kingdom. On the other hand, the mean, as deduced in general principles from the Norfolk data, happens to considerably exceed the actual mean, the periods of observation being only two (viz. before and after puberty). This error in excess, however, though of a different kind, . serves, in the final generalization, to counteract the error of deficiency in the Bristol data. ‘++ Dr. Marcet estimates the mortality in Guy’s Hospital at about 1 in 7. Mr. Mar- tineau, of Norwich, has, I understand, during the last 17 years, performed the operation 85 times. with the loss of only ¢wo. patients. * 428 Dr. Clarke upon a new Blowpipe. (June, From the summary nature of my little volume the above has been omitted, as well as‘a great deal more on some other points, which I fear will in consequence be liable to be misunderstood. { hope, however, to have it in my power to obviate this objection at no very remote period. I am, yours truly, WitiiaMm Provr. ARTICLE V, | Upon a new Hydro-Pneumatic Blowpipe, so constructed as to - maintain during two Hours, uninterruptedly, a Degree of Heat capable of melting Platinum ; and this by propelling the Flame ¥ a small Wax Taper with Atmospheric Air. By Edward aniel Clarke, LLD. Professor of Mineralogy in the Univer- sity of Cambridge, Member of the Royal Academy of “Sciences at Berlin, &c. &c. ! | (To the Editor of the Annals of Philosophy.) “= SIR, ' Cambridge, May 15, 1821. To the various successive improvements which the blowpipe has received, we may now apparently add another, possessed of considerable advantages :—I allude to that form of the instru- ment wherein the air is propelled from a jet by the pressure of a es te of water; this being the kind of blowpipe on which these improvements are founded. ~ The advantages of the old’ instrument consisted in the opera- tor having both his hands at liberty ; and in the relief which it afforded from that fatigue and possibility of injury to the lungs incident to a protracted restraint on their free action, to which persons using the common mouth blowpipe were liable. To these advantages, which the new instrument also possesses, we may add the following : i i. Either common air, or any other gaseous fluid may be used for the propelling current, by condensing it in the reservoir, and thus experiments may be made on the fusing powers of the dif- ferent gases with perfect ease and convenience. . 2. the power of entire exhaustion possessed by the new instrument, ensures the operator from any admixture of common air, where oxygen gas, or any other gaseous fluid is to be employed. | | "3. The old instrument, although very useful for bending tubes, or other ordinary purposes, required to be repeatedly restored to action by fresh supplies of air, at intervals seldom exceeding five minutes, in the common-sized instruments. In the new mstru- ment there is this great improvement; that a steady flame of ‘ 1821,] Dr. Clarke upon.a new Blowpipe. 429 two hours, continuance. may be maintained, of the most perfect, sliape and uniform temperature, uninterrupted by casual currents from the pneumatic reservoir. 7 . | Oe 4, The. troublesome: interruptions caused by the ejection of water, while supplying the apparatus with air, which were com- mon in the old instrument, do not happen in the new one. . 5. The new instrument may remain unemployed for any length of time, being always ready for instantaneous use, and requiring no other preparation than merely that of lighting the wax taper. employed to supply the flame... by ot; , : The manner in which this instrument was brought to its pre-. sent state of perfection, affords an. anecdote which may not be uninteresting to your readers ;' because it will show the force of mechanical skill as it is sometimes remarkably conspicuous in uneducated: minds. A servant of mine, who has been frequently. employed in attendance during my lectures in mineralogy, 'see- ing me reject the old instrument as unfit forthe uses to which I wished to apply it, asked me the reason of my setting it aside. To this | answered that the short space of time in which it con- tinued to propel the flame rendered it inconvenient ; and that I _ would rather use the common mouth blowpipe than be liable to. such frequent interruption from the necessity of supplying it every five minutes with fresh air. ‘This caused him to. inspect the inside of the instrument; when he simply observed, “ Jf as very awkwardly contrived; I could make a better myself!” and in good earnest, without further communication with me upon the subject, he fell:to work, and produced the new improved apparatus, which it is my present purpose to describe, and to make as generally known as possible... The inventor’s name is’ Johnson Tofts.. Upon the principle which he has adopted for. the improvement of his blowpipe, such instruments are now manufactured in London. By means of one of these instru- ments, gold might be exhibited in a state of continual fusion for almost any length of time. is 3 Ce A trial has been made of the use and powers of this improved blowpipe throughout an entire course of public lectures in mine-. ‘ralogy before the University, with such success, as to. produce _ sufficient proof of its. convenience. and efficacy. The, effects witnessed when oxygen gas.was employed exceeded those usually produced by the same agent from a gasometer; owing to the condensed state in which the gas was propelled ; while the cone of flame was much more manageable. . Platinum ,wite of some thickness was fused ; ‘platinum foil offered no resistance whatever. The stee/ mainspring of a watch underwent brilliant combustion ; and even when the instrument is charged with common. atmospheric air, thin cuttings of platinum foil sustain an instantaneous fusion. Had we possessed this apparatus before the gas blowpipe was mvented, many of the results obtained by that powerful instru- 430 Dr. Clarke iipon a new Blowpipe. (Jung; ment would have been anticipated. It is not to be’ expected, however, that the fusing powers of the two'‘blowpipes ean be compared together ; but from the safety of Toft’s blowpipe, a child may use it; whereas the other would be indeed a danger- ous toy. : In the old apparatus, when the instru- = ment is charged, the space E CGH is "o 40 occupied by air, and the water rises to the dotted line C D. ‘When it has been kept ‘in action until the water has its surface at the dotted line AB, the action ceases, ~ ‘ and the space E A F C must always remain filled with common air. In the improved hydro-pneumatic appa- |||. y ratus, which I have called Toft’s blowpipe, when the instrument has been charged. for use, P P is filled 6 sinatt (2 with air, and the water remains ff sper 24 Inches. entirely above it in the vessel Q, whence it will descend through @ the cylinder O E so long as any BY YS eohee. air shall remain in the reservoir dpehide 2) igh! Thchies. P P, and the water will entirely ~ ad fale fill this reservoir ; so that what- oo dayne _ ever air it may be desirable next —— to introduce will again displace - : the water, and drive it up to Q without admixture of common All gases are introduced’ by means of a bladder and a condens- ing syringe, which screws on to the stop-cock F. And it has: been found better to introduce atmospheric air with a syringe than to fill the reservoir with air from. the lungs ; also to hitie the machine with water, or to remove it by means of a common siphon. | he | | The instrument is so simple that a more minute coat of it isunnecessary. Upon these eb te it is manufactured and sold by Mr. Newman, maker of philosophical ‘apparatus, in Lis/e- street, Leicester-square. The usual size of one of these blow- ipes is two feet high, two feet long, and five inches wide. ey are made either of copper or tin, and enclosed in a wooden case, which serves as a table, and a rest for the arms ; the wax taper, being sunk into a cylinder at X, is elevated or depressed by means of a screw and a rack. But a stationary spirit-lamp, if it should be preferred, may be fixed in the same place. I remain, Sir, yours, &c. Epwarpd Dante, CLARKE. 9 4 On Oiliand CoalGas, = ABE Articte VI. On Oil and Coal Gas. (To the Editor of the Annals of Philosophy.) DEAR SIR, : Sheffield, May 12, 1821, IT nore you will indulge me with the insertion of a short reply to Mr. Ricardo’s Bea on Oil and Coal Gas, which appeared in. your last Number. I would not have troubled you with a second paper on this subject, had I not thought it a duty imposed upon me to correct the erroneous statement which Mr. R. made in the spe to his last paper respecting the price of coal gas in effield. } If I had allowed his remarks to have passed unnoticed, he and your readers would be justified in drawing the conclusion, that my first paper was incorrect, and that the consumers of gas im Sheffield were imposed upon by the Gas Light Company, by paying a much higher price for gas than what the Couiipaaiy professed to chargé them. | keke TOM: AR _ Mr. R.’s first paper has been so completely answered, respect- ing the ee od illuminating power of the two gases ‘in uestion, by Mr. Lowe, of Derby, in the Philosophical Maga- zine for the last month, that any further remarks on that head are rendered unnecessary. ep uh agian ! YILGS (90 . Mr. R. still persists m his assertion that the London Chartered Company possess advantages superior to any other, although they only divide 8 percent. and yet otherCompanies have divided 10 per cent. The Sheffield’Gas Works are generally allowed to be as well built, and as completely and conveniently fitted up, as’. those of any other place ; therefore, we may fairly presume that | the capital employed in the buildmgs, &c. will be nearly upon a par with that of the Chartered Company, in proportion. to: the size of the works and the quantity of gas required. To what then must the advantages be attributed in those places (for every oné, except Mr. R. I think, will allow that they have real advan tagés) where the Companies make greater profits, and sell their gas cheaper than at the Chartered Company’s Works! It must be either owing to superior management, and the economy ‘used in that management, or to the cheapness of the destructible articles (retorts, coal, &c.) used in the manufacturing of gas. As ‘Mr. R. is not willing to allow that the cheapness of coal, labour, &c. is of much benefit to a gas light manufactory, though I entirely differ with him on that point, it must be m the economical management that some provincial towns -have the advantage over the Chartered Company. Perhaps Mr. R. will 432 On Oil and, Coal Gas. (June, not be willing to allow this point. However, certain it is, that several Gas Light Companies have advantages which the Char- tered Company has not, or they could not make greater dividends, and sell their gas for a less price. TY admit that it is one great advantage to a Gas Light Company to have the greatest number’ of lights in the smallest compass; but I have been informed by an able and experienced engineer, that the expense of the main ipes in London is as great upon the average, for the same num- er of lights:upon them, as in most of the large country towns. In calorie the price of gas from the rate cards of the differ- ent towns, Mr. R. assumes that all burners denominated No. 3, Argand, are of the same size, and consume the same quantity of gas.. From this supposition arises, ina, great measure, the erroneous statement in his last paper Reape Cag the price of gas in Sheffield.. The No. 1, Argand, used in Sheffield, con- sumes three cubic feet per hour, by Mr. Cleg’s, meter; the No. 2. consumes, 44 cubic feet per hour; and the No.3 consumes six cubic feet per hour. 1 have seen a No. 3, Argand, from Birmingham, tried by the same meter against a No. 2, Argand, such. as are used in Sheffield, and the difference in the quantity of. gas consumed by the two burners was.only half a cubic foot per hour. I likewise, by the same meter, have seen,a No. 3, Argand, with 24 jets, consume seven feet per hour. . Very few No. 3, Argand burners, are used in Sheffield, owing to the. No. 2 being considered nearly equal to'the No. 3, in other laces... The average time of lighting through the year cannot e calculated at a later hour than six o’clock, as that is the average time of the setting of the sun; and we may frequently see the shops lighted up in winter an hour before the time of sunset.. Mr. R. only calculates 34 hours’ burning, till 10 o’clock, which is certainly half an hour at least too little. . The Sheffield card is calculated from six o’clock upon the average; and as the No. 3, Argand, consumes six feet per hour; in 313 Prsangt till eight o’clock it will consume 3756 cubic feet of gas, whic at 12s. per 1000 feet amounts to 2/. 5s. 0¢d.: the charge in the rate card is 2/. 5s. per annum, and yet Mr. R. by his ingenious mode of calculation, says, that the cost price of gas in Sheffield is 17s. per 1000 feet. The charge for the same burner till nine o’clock is 3/. 9s. and till 10 o’clock, 4/. 15s.; the last two charges are rather more than at the rate of 12s. per 1000 feet; but if the rental amount to 20/. a discount of 20 per cent. is allowed, which reduces the gas to less than 10s. per 1000 feet. In manufactories where the meter is used, the regular charge is 12s. per 1000 feet, with a discount of from 5 to 50 per cent. in proportion to the rental, but all rentals of or above 20/. are allowed 20 per cent. I am informed that the annual rentals for, gas in several of the silver-plated manufactories are 50/. and upwards. Gas is found to be so much superior to oil for solder- — 1821.] Prof. Berzelius on the Composition of Prussiates. 433 ing silver-plated goods, that it is generally wsed for that purpose in those silver manufactories where it is introduced. | I hope this explanation will convince your readers that my first statement was not so incorrect as Mr. R. wished to make it appear. _ T remain, yours respectfully, ; A SuBSCRIBER. ArticLe VII. Researches on the Composition of the Prusstates, or ferruginous Hydrocyanates. By J. Berzelius. (Continued from p. 308.) In order to examine whether, in these experiments, the remaining bases be in the state of common carbonate, I heated a mixture of carbonate of potash with six times its weight of oxide, of copper in a proper apparatus for receiving the gas that might be disengaged. As soon as the mixture had acquired a red heat, carbonic acid gas began to be given off, and continued for more than half an hour. Thus the oxide of copper has the property of expelling the carbonic acid at a high temperature, and of formin a kind of double salt, in which it is to be presumed that one-fourth of the potash is combined with the oxide of copper, and three- fourths with the carbonic acid. This salt is decomposed in the humid way, the water seizes a mixture of caustic potash, and carbonate of potash, and the oxide of copper remains undissolved. This last phenomenon also ensues when oxide of copper is dis- ‘solved in hydrate of potash by igneous fusion. ‘The compound, which in the liquid state is transparent, and of a yellow colour, is decomposed by water, which takes the potash, without, at the same time, dissolving the oxide of copper, with which it was combined. : _ It was necessary, therefore, in order to obtain a more decisive result, to analyze a ferruginous prussiate whose base is incapable of retaining the carbonic acid, and I chose for this purpose that _ of lead. | 12°35 grains of prussiate oflead were mixed with 308°8 grains of oxide of copper obtained by calcining copper in a. cupel- ling furnace. The gas was collected over mercury in a ces was receiver, in which it could be accurately measured. o determine with the greatest possible accuracy the relative volume of carbonic acid gas to that of the azote, a portion of the gas collected towards the end of the operation, and consequently free from atmospheric air, was examined separately: 130 mea- New Series, vou. I. 25 : 434 Professor Berzelius.on. \ot Pere, sures placed in contact with caustic. potash were reduced to 45:4 measures; but 45:4 x 3 = 1362; which gives, as exactly as can be expected in experiments of this nature, two volumes of carbonic acid gas for one of azote. Thus this experiment proves that the carbon and the azote, in these salts, are in the same proportions as in cyanogen. No water was formed, except a slight and unimportant trace of moisture.* The whole quantity of gas obtained consisted of 102 volumes of carbonic aid and 51 of azote; the former weighed 3°1 grains, and the azote 0°99 or. which give for 100 parts of salt, 11°05 of carbon, and 12°84 of azote ; or together, 23°89 of cyanogen. This quantity, added to the other element of the salt employed, exceeds its weight by 6:19, if the bases exist in it in the state of oxide; but if the prussiate be composed of one atom of cyanuret of iron with two atoms of cyanuret of lead, the sum of the cyanogen, iron, and lead, obtained, gives almost exactly its weight. It appeared to me very easy to verify this idea by acting on the ferruginous prussiate of lead by sulphuretted ideiguel gas : 18°84 grains of the anhydrous salt were introduced into a small weighed glass ball, blown by the lamp. I caused a current of sulphuretted hydrogen gas to pass through the ball, which, on quitting it, traversed a tube filled with muriate of lime. While cold, the prussiate of lead was not altered by the gas, but on heating the ball by a spirit-lamp, it was immediately blackened, and hydrocyanic acid evaporated with the sulphuretted hydrogen that passed off in excess. No trace of moisture was perceived during the operation, not even when the mass: in the ball was red-hot in the sulphuretted hydrogen gas. The remaining mass weighed 17:06 grs. and was composed of sulphuret of iron, at the minimum, and sulphuret of lead. The tube containing the muriate of lime had only gained 0:0077 of a grain in weight, a part of which was sulphur. ‘Thus-this experiment proves that in the anhydrous ferruginous prussiate of lead the metals are not in the state of oxide ; for even if we suppose in this experiment that no water is obtained, ‘n consequence of the sulphur seizing the oxygen of the metallic oxides, the sulphuric acid, so produced, ought to have combined with.a part of the oxides, and have occa- sioned a much more considerable increase of weight than was obtained in the experiment ; on the other hand, if the salt be really composed of one atom of cyanuret of iron with two atoms. of cyanuret of lead, its decomposition by sulphuretted hydrogen should give for 18°84 grains of metallic cyanuret, 17 grains of sulphuret ; which agrees, as nearly as possible, with the result of the experiment. The composition then will be “ The original has been shortened,.—Edit. 1821.] the Composition of Prussiates. 435 According to experiment, — According to calculation.* SEMA cs isa has tesaeaces tS so ea 678°43 1 PES SERRE Ali ALAR? 1." | RM Ri GOH 5178-00 Carbon..... agatypaptipansy 6 Te, «anh 11-55 ; fia ae dha 1284 ...... 1359 F “°° °" beta 98-61. 100-00 7823-95 Thus the result of analysis approaches that by calculation as near as can be expected in an operation of so complicated a nature. | If we apply this to the salt with base of potash, we get the following result : the relation of the volume of the carbonic acid gas, found by experiment, was to that of the azote as 3 : 2, and the weight of the carbonic acid gas obtained from 7°72 grs. of salt was 4:13 grs.: if we add one-third the quantity necessary to make the volume of carbonic acid twice that of the azote, the weight of the carbonic acid will be rather more than 5:5 grains, or 11 for 100 grains of the salt; but if the ferruginous prussiate of potash be composed of one atom of cyanuret of iron and two atoms of cyanuret of potassium, 100 grs. will give 11-10 grs. of carbonic acid gas, a difference within the limits of maccurate observation. The composition of this prussiate, in the state of crystals, cal- culated after the formula, §Fe Cy? + 2. K Cy* + 6 Aq, gives per cent. i ORGAO CRE i 12°85 = protoxide of iron, 16°54 POCASSIUM. wc CALE. == POtAEl) os os 5 anys 44-68 We A AROS ¥ foe: PIEGEE Save o'y «sie 12°82 I think it useless to give the result of the calculation of the two other salts analyzed. They accordwith the following for- mule: Fe Cy* + 2 Ba Cy* + 12 Aq; and Fe Cy* + 2 Ca Cy? + 24 Aq. But we must remember that, although in a state of efflorescence, these two salts retain an atom of water, for some ‘reason not very easily explained. | These experiments prove that the salts called prussiates, or ferruginous ialntbancicten, are in fact cyanurets, composed of one atom of cyanuret of iron and two atoms of cyanuret of the other metal. What is the nature of these compounds when they contain water? It is more difficult to answer this question than at first it seems to be. In the ferruginous prussiates of potash and lead, there is exactly the quantity of water necessary to trans- - form them into hydrocyanates, whence they may be considered * According to the formula, Fe Cy? + 2Pb Cy* § I use the sign Cy for cyanogen instead of N C*, to avoid complex. numbers. 252 436 Professor Berzelius on - [JuNE, as double hydrocyanates. But are their elements really com- bined in this manner, or may they be regarded also as cyanurets with water of crystallization ! In‘compound substances, whose elements may be conceived to be united in several ways, is it indifferent in what manner we imagine the union to take place? Are the products of their decomposition determined solely by the decomposing power ? A multitude of circumstances concur in favour of this idea. But if it were correct, a compound body, whose elements are capable of combining at high temperatures, in such a manner as to afford other compounds, eee I with a certain tension, at the common atmospheric temperature and pressures, I say this substance must continually decompose in the air, till the tension of its elements is balanced ; and in a vacuum it cannot exist at all. it appears to us that nitrate of ammonia would decompose in this way in a vacuum, ifit were a matter of indifference whether we consider it as composed of an atom of ammonia, an atom of nitric acid, and an atom of water, or of an atom of protoxide of azote and two atoms of water, since, in a vacuum, there is no obstacle to prevent these bodies obeying the influence of their tension, as well as the preponderating affinities, any more than at a high temperature, when those two substances are actually formed. It is.probable, therefore, that the elements of nitrate of ammonia are combined rather as nitric acid, ammonia, an water, than as protoxide of azote and water. In like manner, when a salt effloresces at the common temperature of the atmo- sphere, we consider the water as existing as such in the salt, but retained by so weak an affinity, that it is overcome by its tension. : Fulminating gold and silver explode by very slight elevation of temperature, and water results ; but these substances are permanent in a vacuum. Tbe hydrogen and oxygen which they retain with so weak &n affinity were not, therefore, in the state of water, but combined in another manner, and it is only in the act of explosion that water is formed. But ifin these substances, whose composition depends on so weak an affinity, water be not produced, when the effect of its tension is facilitated by a vacuum, we may presume that all bodies which exhale aqueous vapours in a vacuum must contain water ready formed, and that they retain it by a very weak affinity. ; I put crystals of ferruginous prussiate of potash into a vacuum with sulphuric acid; at the temperature of 35°4° Fahr. they lost all their water of combination : a small piece of a crystal intro- duced into the vacuum of a barometer made it fall 0-005 in. at the temperature of 59° Fahr. I do not give this, however, as a very accurate result, from the extreme difficulty of making a solid body rise through the mercury, perfectly free from air adhering mechanically to its surface. the experiment proves, however, that the water of crystallization in this salt is endued 1821.) the Composition of Prussiates. 437 with a certain tension, which varies with the temperature. It appears, therefore, that tle salt in question contains water ready formed, and not hydrocyanic acid, and oxidated bases ; for it is not very likely that the base and the acid should be decomposed and recomposed, in proportion as the tension of the water varies, according to the temperature and the quantity of aqueous vapour in the surrounding atmosphere. In this case, we must consider the crystallized ferruginous prussiate of potash, as a double cyanuret of iron and potassium, combized with water of crystal- lization, after the manner of salts, all the external characters of which it possesses even in its efllorescent state. IIL. Onthe Hydrocyanate of lron and Ammonia, In order to learn the nature of the ferruginous hydrocyanates with more certainty, I also examined the composition of the ammoniacal one. It appeared to me at first probable that it might throw light upon the true nature of ammonia. If, for example, this salt were reducible to cyanuret of iron and the metallic substance which amalgamates with mercury, when ammonia is decomposed by the electric pile, and if it were pos- sible to obtain this salt free from water, or, what is the same, without oxygen, it is evident that, in this case, it would be a double cyanuret, and it would be easy to determine whether the metallic radical of ammonia is composed of an atom of azote and of six atoms of hydrogen, as appears to result from the experiments of MM. Thenard and Gay-Lussac, or whether it consists of an atom of nitricum and six atoms of hydrogen, according to the conjecture which I have hazarded. In the first case, this salt would appear to be composed of cyanuret of iron and hydrocyanate of ammonia ; and the hydrogen assigned to the hydrocyanic acid would in fact be the additional atom of hydrogen required to metallize the ammonia. In the second case, on the contrary, there would be no other hydrogen than that which is a constituent part of the ammonia. But there is still a third case: it is that this combination might consist of hydrocyanate of protoxide of iron and hydrocyanate of ammonia, and which would not part with the oxygen and hydrogen neces- sary to the existence of the hydrocyanate, without being at the same time totally «lecomposed ; and unfortunately this is the actual state of the case. The experiments necessary to determine which of these cases happens, are neither difficult, nor subject to give ambiguous. _ results. The hydrocyanate must contain four atoms of ammonia and one atom of iron: since the oxygen presupposed in this alkali must be double that which iron absorbs in becoming protoxide. Consequently, in the first case, the salt decomposed by heat ought to leave 27°53 per cent. of its weight of red oxide of iron; in the second, 31°18; and on the third, 25°9. The greatest difficulty in this experiment was that of obtaining the 4388 Professor Berzelius on | [Jung, ammoniacal salt pure, because the prussian blue of commerce affords it much mixed with other substances, and during evapo- ration with them, it constantly decomposes.’ 1, therefore, ai some cyanuret of iron and lead, which I decomposed y caustic ammonia. The solution was evaporated in vacuo, and having powdered the salt, I again dried it m vacuo toseparate all the water mechanically mixed with it. Tn order to determine whether this salt contains any water, I heated it in a small retort made with the lamp, and received the products of the distillation in a long tube, that by the difference of their volatility they might be deposited at different distances from the heated part. ‘The first effect produced by the heat is that of rendering the salt green at the bottom of the retort, and the smell of hydrocyanate of ammonia is perceived at the open end of the tube. The greenish colour was soon succeeded by a greyish-yellow, considerably resembling that of the pulverized -salt before it is heated. The yellowish stratum increased in thickness, and at the same time a very minute greenish stratum which separated it from the unchanged salt gradually rose ‘towards the surface, where it at last disappeared, leaving the salt completely converted into a yellowish-grey mass. During this decomposition, water continued forming and depositing in small drops in those parts of the tube which were near the retort. A great quantity of hydrocyanate of ammonia was at the same time disengaged, and when the salt had driven the atmospheric air out of the apparatus, it began to crystallize at some distance from the water, so that the mterior of the tube was entirely lined with its crystals. The centre, which was at first limpid, became gradually yellowish, and afterwards brown- ish nearer the crystallized ammoniacal salt ; this arose from the spontaneous decomposition which hydrocyanate of ammonia suffers. This salt did not contain any water chemically combined ; for it was crystallized in the form of little rectangular tables and prisms, which are the usual forms of this salt when it is prepared with ammoniacal gas and hydrocyanic acid free from water. The yellowish mass contained in the retort was cyanuret of iron, the lower part of which had begun to decompose before the upper part was entirely deprived of water and hydrocyanate of ammonia. By continuing the heat, the cyanuret of iron became of a deeper colour ; first, brown ; and at last, black, and. disengaged azotic gas. In order to satisfy myself that the decomposition was com- lete, 1 placed the small retort in a charcoal tire to make. it red- ot, when, to my great surprise, the coaly mass burned vividly, as if oxygen gas had been present in the retort. A small quan- tity of undecomposed ee of iron disengaged azotic gas with so much rapidity, that a part of the mass was thrown into the neck of the retort. When the retort was cold, it was found to contain a black pulverulent mass, weighing 25°25 per cent. 1821.] the Composition of Prussiates. 439 of the hydrocyanate employed. This substance, when heated in ‘the flame of a lamp, took fire, and continued to burn like amadou, but without either smoke or smell, and it left a residue of oxide of iron, the weight of which was precisely equal to that of the mass before combustion. -‘In.another experiment, I heated the hydrocyanate by a spirit lamp, taking care not to heat it enough to occasion the deflagra- tion which occurred in the former case ; but the heat was con- tinued as long as the disengagement of gas was perceptible, and the products of the distillation were passed through a tube containing muriate of lime, and the gases received .over mercury. The coaly residuum weighed 26'3,.and gave by com- bustion in an open vessel exactly 26:3 of red oxide of iron. It burned as before, but without the deflagration abovementioned occurring at the temperature required to inflame it. The muriate of lime gained 9-7 percent. of the weight.of hydrocyanate. When heated, it gave out at first much hydrocyanate of ammonia, afterwards ammoniacal gas, and lastly water much impregnated with ammonia. In this experiment, the quantity of water could not bedetermined, but it proves nevertheless that thesalt cannot con- tainmorewaterthan is requisite to convertthe cyanuretof iron into hydrocyanate :. for otherwise the muriate of lime ought to have gained much more. The gases produced contained no trace of carbonic acid... I introduced some lime-water which absorbed a great quantity without becoming turbid. ‘The liquid contained much hydrocyanate of ammonia, and the unabsorbed gas was azote. The explanation of these phenomena is very simple : the hydrocyanate of iron and ammonia is decomposed by heat, and. ore hydrocyanate of ammonia, cyanuret of iron, and water. The green colour which appears during the decomposition appears to be owing to the formation of a small quantity of prussian blue, which always begins the decomposition of this salt, even when in solution. When the heat is increased, the cyanuret of iron is decomposed, azote is disengaged, and the carbon remains combined with the iron. As cyanuret of iron contains four atoms of carbon to one of iron, the same propor- tions ought to be found in the carburet which results frorh ‘its decomposition. Then in comparing the weight of four atoms of carbon with that of three atoms of oxygen, the first is found to be 301°66, and the last 300; so that when the quadricarburet of iron is converted into red oxide of ‘the metal, its weight should not alter more than 1-1000th, which is too small to be ascertaied in experiments made upon so minute ascaleas mine. As to the deflagration, I shall hereafter have occasion to mention it. I tried several times to expose the hydrocyanate of iron and ammonia to temperatures very gradually raised im order to see whether it-would not be possible to separate the water, and preserve the hydrocyanate ; that is to say, to reduce this salt to the composition supposed in the first case; but I have not 440 Professor Berzelius on [JuNE, succeeded. The water and the hydrocyanate are always disen- gaged together, and the salt becomes green. Even when after being highly dried, it gave a residuum by combustion of 28°5 per cent. of oxide of iron, it still yielded water by distillation ; so that in drying it, I only commenced its decomposition, which is facilitated by the great tension of hydrocyanate of ammonia, and 3 the tendency of the hydrocyanate of iron to form prussian ue. IV. Prussian Blue. [ prepared this’ substance by dropping a solution of cyanuret of potassium and iron into one of muriate of iron, to which I had previously added excess of acid. 1 washed the precipitate tho- roughly and dried it. Prussian blue retains hygrometric moisture so strongly, that sulphuric acid in vacuo does not detach it; and I have no doubt but that this salt when dried would possess the property of causing water to freeze in vacuo quite as well as sulphuric acid and some other substances. tbat some prussian blue into a cylindrical glass which I placed in a small sand-bath. I placed the bulb of the thermo- meter in the middle of the prussian blue, and heated the sandbath gradually until the thermometer rose to 307° Fahr. The prussian blue did not appear at all changed, and gave out no odour either of hydrocyanic acid, or hydrocyanate of ammonia. I afterwards placed the sand-bath thus heated in vacuo, with sulphuric acid, and suffered it to cool. A portion of prussian blue thus dried. was weighed as quickly as possible, and then lighted at the edge. It continued to burn by itself like amadou, giving a vapour which condensed upon a funnel inverted over it: it was carbonate of ammonia. One hundred parts of prussian blue left a residuum of 60°14 parts of red oxide of iron, containing no potash. 2 : , : It is well known that when a solution of protoxide of iron is precipitated by prussiate of iron and potash, a white insoluble compound is formed which contains potash, and which by absorbing oxygen becomes blue. It is also well known that a salt with base of protoxide, which absorbs oxygen without there being at the same time an increase of acid, combines with an excess of base. Prussian blue, therefore, which is prepared b oxidwtion of the white precipitate, cannot be a neutral compound. [ added a solution of neutral muriate of deutoxide of iron to a solution of cyanuret of iron and potassium, and [ left the mixture exposed to the air until it became blue. The liquid which still contained undecomposej ~yanuret, remained neutral ; this circumstance proves that no p.tash was set free, and conse- quently that the blue compound did not contain a quantity of acid proportional to the capacity of the base which had been increased by oxidation. Prussian blue thus prepared has properties which it does not | 1821.] the Composition of Prussiates. 44] possess when differently prepared, and which may become of some utility in the arts. It is sokuble in pure water, but not in water which contains a certain quantity of any neutral salt. It is on this account that it does not dissolve when it is washed, and. even the greater part of the saline matter is separated from it. A clear blue solution then passes through the filter; but it again precipitates prussian blue, if it falls into the liquid which had previously passed through. I made use of a solution of sal ammoniac to separate it from other salts. I washed it with a small quantity of water, until it began to be coloured ; and I afterwards dried the precipitate by pressure between paper. The blue solution is precipitated by the addition of muriatic acid, but the precipitate does not lose its solubility in pure water. The blue solution is not rendered turbid by alcohol. This solubility of prussian blue is not always the same. Sometimes the whole of the precipitate rendered blue by oxidation in the air is soluble ; at other times, more or less of it remains insoluble. Ebullition produces no change in its solubility. This property ma substance, which under other circumstances is so insoluble, appears to be of the same nature as the solubility of the oxides of tin and titonium, and also of silica, the solubility of which is evidently different in its nature from that of salts. As the addition of excess of acid does not deprive prussian blue of its solubility in pure water, it is evident that this property does not depend upon an excess of base. In order to compare these phenomena with those which occur in insoluble salts of protoxide of iron, { examined the changes produced by oxidation in some of the latter. A great number of them may be preserved without undergoing alteration, or they become yellow by the formation of a salt, with peroxide in excess. But there are two, viz. the phosphate and the arseniate of pro- toxide of iron (the acids of which combine with bases, according to a different law from other acids), which, by absorbing oxygen from the atmosphere, change their white colour into a darker one, and form salts with excess of base differing as much from salts of the protoxide as of the deutoxide. ‘The phosphate becomes blue; it is even found in nature partly blue and partly _ white ; but in this latter case, it becomes blue in the air in a few days. The arseniate, on the contrary, becomes of a deep green colour. The two varieties of the arseniate appear also to be found in nature. The neutral salt has been lately found in Saxony: it is called scorodiée ; it.is a salt which contains water, and has the same colour as protosulphate of iron: the other has been long known; it is the cubic arseniate of iron. | There 1s, however, an essential difference between these salts and prussian blue. They do not form double salts with other bases ; and when they are decomposed by caustic potash, they do not yield hydrate of deutoxide of iron, like prussian blue. On 442 - Professor Berxeliuson (June, the contrary, the potash combining with their acids leaves a substance as black as charcoal, which contains no combined water, and which suffers much less change during washing than the protoxide : it is this compound of deutoxide with protoxide which I have named oaidum ferroso-ferricum; and it is to be presumed that the composition of these salts may be expressed by It appeared to me extremely probable that prussian blue might be a completely analogous compound. Its formation by means of double decomposition ought then to destroy the neutrality of the two saits formed, and free acid ought to be liberated. I prepared a solution of neutral muriate of deutoxide of iron, and after having determined by a correct analysis the relation of the acid to the oxide of iron, in order to satisfy, myself of its being neutral, 1 added it drop by drop to a solution of cyanuret of iron and potassium, which did not change the colour of tournsol. When the greater part of the cyanuret was decom- osed, | suffered the precipitate to remain. The clear liquid was ound to be as neutral as at first, so that the precipitate was as neutral a compound as the substances employed to prepare it. I continued to add the muriate of deutoxide of iron until it was m excess. The liquid had then acquired the property of slightly reddening the tincture of turnsol, as must happen from the excess of muriate employed. The prussian blue produced in this expe- riment can, therefore, only be a double hydrocyanate in which the oxygen of the deutoxide is double that of the protoxide. - _ LT afterwards analyzed some prussian blue thus prepared, by digesting it with excess of caustic potash. The: undissolved oxide of iron was separated and washed,* and the alkaline liquid (which with the protoxide of the decomposed blue had formed eyanuret of iron and potassium) was decomposed by the addition of corrosive sublimate, the digestion being continued for some hours. The oxide of iron precipitated by this process was washed and strongly heated to separate the oxide of mercury which was precipitated with it. The oxide of iron, separated from the prussian blue by potash, was to that separated by cor- rosive sublimate as 30 to 22. | . If the prussian blue were analogous to the phosphate and arse- niate alluded to, the two weights of the oxide. of iron ought to have been in the proportion of 2 to 1. I, therefore, repeated the experiment with the prussian blue, washed, but not dried, in order that it might not be changed by the drying, and the two weights thus obtained were 70-5 parts of oxide of iron, separated by the potash, and 52 parts precipitated by digestion with the * TI satisfied m i io , that the oxide of iron thus _I satisfied po es an reer) previously made, that the oxide 1821.] the Composition of Prussiates. — 443 corrosive sublimate. These proportions being neither as 1 to 2, nor as 2 to 3, 1 thought it requisite to examine whether the caustic potash did not in some way decompose cyanogen. I, therefore, analyzed prussian blue by digesting it for a long time with bicarbonate of potash. The decomposition was complete, the bicarbonate left 31 parts of oxide of iron. The yellowish solution was supersaturated with nitric acid, evaporated to dry- ness, and the dried mass was exposed to a red heat. This mass being washed with water left 23 parts of oxide of iron undissolved. All these numbers agree together, and the two portions of oxide of iron obtained in each experiment are in the proportion of three atoms of oxide of iron and four atoms of the same oxide; that is to say, = 2935:29 : 3913°72. The analysis then proves decidedly, that in prussian blue prepared in this manner, the oxide of iron contains twice as much oxygen as the protoxide, and consequently its composition is proportional to that of other cyanurets or ferruginous hydrocyanates ; this is also demonstrated by the substances from which prussian blue is precipitated, remaining neutral. But what is then the blue mass which is produced by the oxidation of the white hydrocyanate of iron? This compound cannot be neutral, foritdoes not meet with any acid to saturate it, nor can it contain oxide of iron mechani- cally mixed ; first, because I have often seen it totally dissolve in-water; and secondly, because the hydrate of oxide of iron must alter the fine blue colour to green, as happens if the solu- tion in which it is formed contains an excess of the ferruginous salt. | The experiments which I have made to analyze prussian blue by means of combustion have not given me as decisive results as | expected. A quantity of prussian blue dried at a high temperature gave 58 per cent. of oxide of iron by combustion. Another portion of the same prussian blue, weighed an instant after the former, was burned with oxide of copper, taking the same precautions as already mentioned. The water, carbonic acid, and azotic gases, obtained, indicated 45°6 parts of carbon, and 53:1 of azote = 98°7 parts of cyanogen. The prussian blue employed contained such a portion of metallic iron as would combine almost precisely with this quantity of cyanogen to become cyanuret ; and by adding together the weight of the iron, cyanogen, and of the water obtained, the weight amounted almost precisely to that of the prussian blue employed, without leaving any thing for the weight of the oxygen of the oxide of ion, which ought to exceed the hydrogen of the hydrocyanic acid, if the compound had contained excess of base. 3 I repeated this experiment with prussian blue precipitated from a neutral solution of muriate of deutoxide of iron, and dried in vacuo, without heat. It left after combustion 54-66 per cent. of red oxide of iron; when burned with oxide of copper it 444 Professor Berzelius on (June, yielded carbonic acid and azote which indicated aimost precisely the same quantity of cyanogen as in the former experiment. B adding together the weight of the water, iron, and cyanogen, it almost precisely equalled that of the prussian blue employed. No one of these experiments indicated, such a relation of the iron to the cyanogen as ought to have been obtained according tothe experiments made in the humid way, and already described ; they leave, therefore, some uncertainty as to the true nature of this substance. . I treated some prussian blue recently prepared, with muriatic acid to separate the excess of base, and after having well washed it, | mixed it with pure water, and passed a current of sulphur- etted hydrogen gas through it, until the water was saturated with the gas. I then corked the bottle, and left these two sub- stances to react upon each other for several days. The prussian blue became of a lighter blue colour, and eventually became of a dirty white. The fluid became whitish with the sulphur precipitated ; Lafter- wards separated the white mass, and I evaporated the excess of sulphuretted hydrogen gas by exposure to the air. This fluid now reddened tournsol, and precipitated of a blue colour those salts of iron which contained deutoxide. ‘lhe sulphuretted hydrogen gas on reducing the deutoxide of iron of the prussian blue to the state of protoxide, and then separated from it that portion of hydrocyanic acid by which the deutoxide had been neutralized in the same way as occurs with every other neutral salt, whose base is a deutoxide, when the sulphuretted hydrogen reduces it to the state of protoxide. It must also be observed that the acid liquid in question contains no pure hydrocyanic acid ; it still contained iron : it was the ferruginous prussic acid, which I shall hereafter consider. The mass which was rendered white by the action of the sulphuretted hydrogen regained its blue colour by exposure to the air, and became at the same time partly soluble in pure water. The blue solution again treated with sulphuretted hydro- gen deposited a black substance, did not again become acid, nor did it again acquire the property of precipitating the solu- tions of deutoxide of iron ofa blue colour. In the same manner, the insoluble portion of the regenerated blue became black by sulphuretted hydrogen. These experiments prove then that there are actually two blue compounds, one of which is neutral, and composed of three atoms of hydrocyanate of protoxide and four atoms of deutoxide of iron; that is to say, the last contains twice as much oxygen and acid as the first. The other appears to be composed of an atom of hydrocyanate of protoxide and of two atoms of subhydrocyanate of deutoxide of iron, analogous to the blue phosphate of iron and the green arseniate of the same metal. 1821.] the Composition of Prussiates. 445 It is evident that the phenomena produced by the metallic cyanurets and hydrocyanates can be explained only by a theory analogous to that proposed for the muriates by MM. Gay-Lussac and Thenard, and which was afterwards adopted and developed by Sir H. Davy; and this analogy of the phenomena presented by the cyanurets is undoubtedly a circumstance which is very favourable to this theory. It seems to follow from the experiments above-mentioned, that the cyanurets of very electro-positive bases; that.is, of the metals which form alkalies, do not decompose water, and do not form hydrocyanates. The weaker bases, such as glucina,* ammonia, the greater number of metallic oxides, on the contrary, become hydrocyanates, which, when exposed to a high temper- ature, either do not become cyanurets, or do not form them without having a part of their cyanogen decomposed by the oxygen of the bases, and yielding at the same time carbonic acid, ammonia, and metallic carburets. With the exception of hydrocyanate of iron and ammonia, it appears that when one of the bases occurs in the state of hydrocyanate, the other is so likewise ; so that there is no compound of a cyanuret and a hydrocyanate. When the cyanurets combine with an additional quantity. of base, it appears that the cyanuret becomes an hydro- cyanate, and that the whole becomes a subhydrocyanate ; such is probably the state of combination of cyanuret of mercury with oxide of mercury. | Before 1 conclude these observations, I shall say a few words upon the acid called ferruginous hydrocyanic acid, and which has been. considered as a peculiar acid, of which the iron is an - element. This compound is produced when a stronger acid combines with the second base of a ferruginous hydrocyanate ; then the whole quantity of hydrocyanic acid combines with the protoxide of iron, and these results are hydrocyanate wish excess of acid, in which the protoxide is combined with three times as much acid as in the neutral salt. All that I have already stated upon the nature of the cyanurets and ferruginous hpdrocyanates is evidence in favour of this manner of regarding this acid sub- stance. Porrett has described two methods of obtaining this acid, one of which is to decompose the cyanuret of iron and barium by “sulphuric acid; and the other to decompose the cyanuret of iron and potassium by means of a solution of tartaric acid in alcohol. The fluid being left to spontaneous evaporation, crystals are. obtained. Neither of these methods gives the superhydrocyanate of iron in a pure state. * Glucina gives a soluble hydrocyanate, which, reduced by evaporation, becomes a transparent varnish, which is often bluish. It isobtained by the double decomposition of sulphate of glucina and cyanuret of lead and iron. There is also a ferruginous hydro- cyanate ofalumina. When neutral, it is but slightly soluble ; but with excess of acid, it may be dissolved. It is prepared with hydrate of alumina and ferruginous prussi¢ acid. , 446 ‘Professor Berzelius on: [JuNnE, I prepared it in the followimg manner: I took ‘some cyanuret of iron and lead which had been well washed but not dried, and I decomposed it under water by a current of sulphuretted hydro- en gas, until the sulphuretted hydrogen was in excess. I rome filtered it, and evaporated it im vacuo in the usual manner. Kut as sulphuretted hydrogen spoils the air-pump, I afterwards took the precaution to decompose the awiphousetail hydrogen by the addition of a small quantity of cyanuret of iron and lead. The filtered fluid remained limpid and colourless in vacuo, and it eventually leaves a milk-white opaque substance, which has no appearance of crystallization. This white matter has the following properties: it dissolves im water, to which it imparts an acid and agreeable flavour, but which is rather astringent. In contact with the air it deposits prussian blue, and assumes a greenish colour. It is inodorous, unless it has begun to decompose. When hoiled, the liquid gives out hydro- cyanic acid, and deposits a powder which becomes blue in con- tact with the air. It is necessary to boil it for some time to decompose it entirely. The fluid, when half decomposed by ebullition, has seemed to me to possess a more astringent taste ; I will not assert, whether by this operation, there is formed an hydrocyanate of iron with a smaller excess of acid. If cold water be saturated with dry superhydrocyanate, and the solution be suffered to remain, it gives small transparent colourless crys- tals which appear to contain water of crystallization, but I have not been able to determine their form. The crystals are formed im groupes composed of concentric rays. The rays appeared to me to be quadrilateral prisms. If I were permitted to conjecture, I would say that these crystals are a losieerrvantts im which water replaces the second base that existed with the protoxide of iron. The white substance obtained by evaporation in vacuo does not appear to contain any water, or rather appears to be the super- hydrocyanate of protoxide of iron without water of tard i tion; for if it be distilled in a small and proper apparatus, it gives at first hydrocyanic acid; afterwards carbonate of ammo- nia and prussiate of ammonia. The production of ammonia in this experiment proves that what remains after the hydrocyanic acid which is first evolved is a hydrocyanate, and not a cyanuret, because, in the latter case, it could only have given hydrocyanic acid and azotic gas. This substance may be Capt without alte- ration in well-closed vessels, but in the air it gradually decom- oses, becomes at first greenish, afterwards blue, and finishes y being entirely converted into prussian blue. V. On the Decomposition of Hydrocyanates by Exposure to a High Temperature in close Vessels, It is evident from what I have above stated that several cya- nurets when exposed to heat in closed vessels must exhibit 1821.] the Composition of Prussiates 447 phenomena differing from those which) have been hitherto admitted. . . | | I have examined some of them with this view, and I think that [can draw conclusions from my experiments regarding the whole class of cyanurets. ee 1. Cyanuret of Iron and Potassium.—lI heated this in a small apparatus, so arranged as to collect the gases evolved. Ata heat near redness, it melts; and before this, it gives nothing volatile or gaseous. But at a strong red heat, it is filled with small bubbles which are disengaged at long intervals, and it remains in this state, even at a temperature at which the glass softens. While cooling, it has a deep-yellow colour; but “it becomes almost colourless upon cooling to the temperature of the atmosphere. Dissolved in water, it leaves a small quantity of quadricarburet of iron in black flakes, and the solution has alkaline properties and smells of hydrocyanic acid. The gas obtained possessed all the characters of azote. The cyanuret of potash separated from cyanuret of iron thus decomposed gives hydrocyanate of potash with water, from whence its alkaline property and hydrocyanic odour are derived. — 2. Cyanuret of Iron and Barium treated in the same’ manner is more easily decomposed at a red heat, gives abundance: of azotic gas, and leaves a residuum of cyanuret of barium and quadricarburet of iron. The decomposition is usually so ‘com- plete, that the solution gives no blue with solutions of deutoxide of iron; but there are obtained a solution of a fine purple-red colour, and a red: precipitate. This red compound was first observed by M. Vauquelin: he obtained it by treating deutoxide of iron by hydrocyanic acid. That which was obtained in the manner now described was not decomposed by ammonia; and after being evaporated to dryness, it was again partly soluble in water. Another part appeared to be decomposed, and was changed into a greenish mass. - ) 3. Cyanuret of Iron and Calcium is still more easily decom- posed than that of barium. As it retains more water relatively to its volume, it gives small drops of water, and a little carbonate and hydrocyanate of ammonia. Towards the end, and when the heat becomes red, it burns, but not vividly, in the same manner as before observed, with respect to the hydrocyanate of iron and ammonia. . . 4. Cyanuret of Iron and Lead.—If it contains water, hydro- cyanate of ammonia is obtained, which readily decomposes, and becomes brown. Ata red heat, it begins to evolve azotic gas, and gives nothing else. When the disengagement of gas is finished, if the retort be put im the middle of the fire, vivid com- bustion is'produced. If this temperature be employed before the cyanuret is decomposed, the disengagement of azotic gas occurs with such rapidity during the combustion, that a portion of the .coaly mass is carried up with it. If all the water has 448 Prof. Berzelius on the Composition of Prussiates. [Jun i, been separated from the cyanuret before the commencement of the experiment, the residual mass is a double carburet, composed of an atom of quadricarburet of iron and two atoms of quadricar- buret of lead, Fe C* + 2Pb C*. If, on the other hand, the cyanuret contains water, one iar of the carbon of the cyanogen is converted into carbonic acid at the expense of the water, and there is a deficiency of carbon in the quadricarburet of iron. It has been supposed that the residual mass, after the decomposi- tion of cyanuret of iron and lead, is a kind of pyrophorus ; this is an error probably derived from the circumstance of the carbu- rets thus obtained taking fire readily at. a lower temperature than is sufficient to inflame other bodies, so that, if the retort be broken before the contents are cold, they take fire, and continue to burn like amadou. 5. Prussian Blue.—Prussian blue treated with muriatic acid was dried at the temperature of 336 Fahr. and afterwards decom- posed. It gave at first pure water, then a little hydrocyanate of ammonia, and afterwards a great quantity of carbonate of ammo- nia, but always followed by moisture. After the evolution of the volatile bodies, I placed the retort in the middle of burnin charcoal, and there was produced a quick. and brilliant combus- tion, as with the hydrocyanate of iron and ammonia. 3 Fifty parts and 7-10ths of the black mass which remained in the retort were burned in a small capsule previously weighed, 54°86 parts of red oxide of iron were left. This relation between the weights of the carburet of iron and that of the oxide, agrees precisely with a tricarburet of iron Fe C*; for, according to calculation, 50°7 of tricarburet of iron ought to give 54:89 parts of red oxide of the metal. As water er 2 Ba i of the decomposition of prussian blue, from the beginning tothe end, it is evident that the affinity of iron for carbon keeps them ina fixed state of combination, and consequently the proportion - of carbon in the carburet of iron obtained by the decomposition of prussian blue is not an accidental circumstance. 6. Hydrocyanate of Iron and Copper.—This. compound con- tains water, besides that which converts it into hydrocyanate. It pies during decomposition much water, some carbonate, and ydrocyanate of ammonia. The phenomena of combustion may be produced in the mass, but for this purpose, a very high tem- perature is necessary, and yet it is not very brilliant. . The resi- _ dual mass is black, and possesses the external characters of those already described. ' [t inflames readily, and continues to burn by itself; 27:7 parts of carburet yielded. 28:9 of the two oxides, both at the maximum of oxidation. The numbers agree with « compound of an atom of quadricarburet of iron and two atoms of bicarburet of copper; that is to say, Fe Ct + 2:Cu C*. 7. Hydrocyanate of Lron and Cobalt.—If this hydrocyanate is well dried, it gives only a small quantity of water, carbonate and hydrocyanate of ammonia, at the boiling point of mercury. Its 1821.] Mr. Deuchar onthe Discharge of Ordnance. 449 > deep green colour changing at the same time, and becoming of a lighter green. At a higher temperature it blackens, gives azotic gas, and finishes by deflagrating. . The black mass appears to be Fe C* + 2 Co C+, of which a small quantity of carbon is accidentally lost by the presence of an indeterminate quantity of adhering moisture. a 8. Cyanuret of Mercury has been so thoroughly examined by M. Gay-Lussac that I have nothing to add, excepting that the coaly mass which remains after the decomposition of this cyanu- ret is derived from the formation of carburet of mercury during the decomposition, and this is the reason why the cyanogen is always mixed with azotic gas. It is this carburet which renders the mass black, and at last, when exposed to a high tempera- ture, the mercury is volatilized, and the charcoal remains. There is also a double cyanuret of iron and mercury, or rather a double hydrocyanate of protoxide of iron and deutoxide of mercury. It is obtained by dropping a solution of corrosive sublimate into one of cyanuret of iron and potassium. . A white precipitate is formed; but it is decomposed not only by ebulli- tion, which causes the. cyanuret of mercury. to dissolve, and leaves that of iron insoluble, but also by the contact of the air, which causes the cyanuret. of iron to become prussian blue; so that I have not.been able to obtain it in a dry state. 9. Cyanuret of Iron and Silver becomes bluish by exposure to a little too much during drying. It is a cyanuret, and not an hydrocyanate. When decomposed, it gives at first cyanogen, and afterwards, when the cyanuret of iron begins to decompose, it gives azotic gas. ‘The phenomenon of combustion occurs at a lower temperature than with other cyanurets. The residual mass is a mixture of metallic silver and quadricarburet of iron, from which the silver may be separated by being well tritu- _ rated with mercury. | | (To be continued.) ArticLe VIII. On the Application of Howard's Fulminating Mercury io the Discharge of Ordnance. By John Deuchar, MWS. Lecturer on Chemistry in Edinburgh. (To the Editor of the Annals of Philosophy.) SIR, . Edinburgh, March 7, 1821. I HAVE just read a communication from your correspondent T. N. R. M.in the number of the Anna/s for this month. He seems to have overlooked that part of my paper near the top of page 91, in which I mention that I had used fulminating mercury, New Series, vou. 1. 2 F wt 450 Prof. Buckland on.the\Structure of the Alps, [Jun; and that it rent asunder the steel plate at the top of the appa- ratus without firing the gunpowder at the bottom. However, as he suggested the trial of different proportions of the fulminating mercury with sulphur and charcoal, and that too with the. know- ledge of mixtures of these three ingredients having. been used in several secret experiments some time ago performed in Panis, I have repeated my experiments with Howard’s fulminating mer- eury weakened with the above two inflammables. I first tried to fire gunpowder with it, through flannel, at the bottom of the : oe (Plate ILL. fig. 1), p..89,,when | found that, it not only did not inflame’ the gunpowder, but failed completely in tearing, or even moving, the paper at the» bottom of the tube. 1 next tried the effect of exploding the mixture» at the top, when the tube presented no resistance at all to any flame that might pass along, but i found thatino light. appeared at the bottom, although ‘TD performed: the whole ina dark: situation. I then shortened the tube, but still found that there was no flame sent out at:the endofit. . ? In some of these experiments, equal parts of Howard’s fulmi- nating mercury, sulphur, and. charcoal, were used; in others; two parts of the mercury were taken to one part of each of the rest; and im others again the proportions were still, further varied. I remain, yours respectfully,,....5 0 3) rm I ites esh i Jonn Deucuar. ArTICcLE EX. Notice of a Paper laid before tke Geological Society onthe Siruc+ ture of the Alps and adjoining Parts of the.Continent, and their Relation to the Secondary and Transition Rocks of England. By the Rev. W. Buckland, Professor of Mineralogy and Geo- logy in the University of Oxford; FRS, FLSs MGS. &c. Tue detail of the phenomena of which! have endeavoured to include a brief summary in this prospective notice, will form the subject of a future and more.extensive communication to the Geological Society. My immediate object is. to present an abstract of the leading points of reseniblance between the rocks of the Alps, and those which occur in our own country. Of the primitive alpine rocks that. form the central axis of this most elevated ‘and most important mountain chain in Europe, I have only to observe that they present such an identity of sub- stance and circumstances with the primitive rocks of other.parts of the world, that any detailed account of them will be unne+ cessary. But with regard to the transition and secondary strata. that ~ 1821.] and adjoining Parts of the Continent. 451 ccur in these same elevated regions, much difficulty exists, and much error prevails, which it will be my object to endeavour to ‘dy away. | : diag f The term transition (for example) is applied by many of the -first geologists of the Continent to a class of alpine rocks of the same age with those which in England are justly considered secondary, and which constitute the new red sandstone, or red rock marl formation, of the English geologists; and the alpine ‘limestones which have been supposed to have pretensions to high ‘antiquity will be found on closer examination to be contempora- neous with the magnesian limestone, and oolite formations of England, and consequently more recent than our great coal for- mation and mountain limestone; with which latter its name, external aspect, and elevated position, would. at first seem to associate it. It will be found moreover that the mountain lime- stone and great coal formation ‘of England do not occur im the Alps. _ The tertiary formations also constituting the molasse and -nagelflue of the Great Valley of Switzerland’ have been mistaken for the new red sandstone beds of England. The causes of these mistakes I shall point out, and endeavour to doaway ; they consist partly in the enlarged bulk, and parth in the want of distinct features, and of tangible character, whith accompany all secondary strata as they enter the Alps. Ishall hope, however, to prove their identity with English formations by the evidence of actual sections ; and to show that a constant and regular order of succession prevails in the alpine and transalpine districts, and generally over the Continent, and that this order is the same that exists in our own country. But though referrible to the same system, and coeval in point of time, and conformable with respect to their relative order of succes- ‘sion, the formations of England and the Alps are much discuised -by local circumstances, and present widely varying features, the extremes of which it would be impossible to identity without the fortunate interposition of certain connecting links that are equally related to, and partake equally of, the characters of them both. The most. remarkable anomaly is the total absence of the English mountain lime and coal formations ; while our oolite and magnesian limestones (under the name of alpine limestones) rise unto the most elevated crests and pinnacles that crown the sum- mits of this gigantic chain. The fcllowing are among the greatest heights which they occasionally attain : | Feet. Ortler; iarFyrokiy.. ob. o. CUE id, CH, 14,466 Jungfrau, in Switzerland .......... 12,872 Dodi Berg, in ditto .............. 10,059 Tiltis -8Us Se PIS E ETI A ols TOOCO Diableretz ......... eee Ue. Ca ORO Dent de Morcle......... CO PA OF Oe 452 Prof. Buckland on the Structure of the Alps, [Junx, In the Pyrenees also we find the same limestones forming the most elevated ridge and great water shed of that vast chain, and rising in Mount Perdu to 10578 feet, and in the Torre de Mar- bore to 10,260. , | ; These alpine limestones include nearly all the calcareous: for- mations of England, from the magnesian limestone which lies next above our coal, measures upwards to chalk, piled on each other without any subdividing strata of clay or sand, and.all assuming the common character of a compact grey marble, pos- sessing no variations by which one part of the formation can’be distinguished from another. And such is generally the feature- less condition of the great calcareous masses, which, extending from: the Pyrenees through the south of France by Avignon to Dauphine, stretch thence uninterruptedly through Switzerland, ‘Tyrol, Saltzburg, and Styria, to the Danube below Vienna; while on the south side of the central Alps a similar calcareous -mass extends from the Lago Maggiore and Como through: the Italian Tyrol into Croatia and Dalmatia. Fortunately this want of distinguishing feature is not universal; occasionally spots occur in which the strata present evidences which identify them with those of England, and throw light on the-history ot the targer and less distinctly characterized masses of which they form a part. | : The general structure of the Alps, and Jura mountains, and the valleys adjacent, reduced to their most simple form, may be briefly stated thus : ‘ | 1. General Structure of the great Alpine Chain. The central. axis of this vast chain extending continuously north eastward from Savoy through. Switzerland, Tyrol, and Styria, to Presburg, is composed of primitive rocks, the average breadth of which is about 60 miles... In.contact with these are extensive masses of transition rocks, but, their presence is irregu- lar; and when they occur, there 1s nothing in the external features of the country to mark their junction with the primitive masses. This central ridge of primitive ad transition rocks is bounded on each side by two vast belts of alpine limestone, coextensive with, and continuous beyond the primitive chain. The elevation of the latter sinks gradually as it advances north eastward, till, near Presburg, it. drops below the bed of the Danube, and on the north of that river again gradually rises to form the chain of the Weise Gebirge whigh connects the Alps with the Carpathians. The lateral belts of alpine limestone maintain their elevation more constantly than the primitive chain, and extend themselves far beyond it; the north belt’ stretching north-westwards from Dauphine into Languedoc, and to the Pyrenees, and the south belt south-eastward by Carniola into Dalmatia. These lateral belts are divisible into two systems, the elder and younger alpine limestones; the former contemporaneous 1821.] and adjoining Parts of the Continent. 453 with the magnesian limestone that rests in the coal formation of England, and characterised by containing gypsum, salt and metallic ores, and occasionally beds of saliferous marl, red sand- stone, and rouhwacke ; the latter entirely destitute of all these substances, and comprehending beds which their organic remains and superposition to the elder alpine limestone and occasional structure show to be contemporaneous with the lias and oolite, and sometimes green sand and chalk formations of England... The chalk seems to occur only on the Italian side of the Alps, near Vicenza. ea These beds of alpine limestone are bounded externally by the Tertiary formations of the Plain of Lombardy on the south ; and by similar tertiary formations in the Great Valleys of the Danube, and of Geneva on the north. Internally, they are terminated by two precipitous escarp- ments; one on each side of, and both rising towards, the central primitive ridge. Between these two escarpments there are detached ridges and insulated or outlying masses of the same alpine limestone covering occasionally large tracts of the intermediate primitive country. ; Note.—The great north escarpment produces a remarkable effect upon the upper courses of all the important rivers that rise on the north side of the central watershed of the Alps, i. e. the Iserre, Rhone, Rhine, Inn, Salza, and Enns. Most of their tributary streams take origin in the central pri- mitive ridge, and descend. northwards till they meet the great escarpment of the alpine limestones. On approaching this, they are suddenly deflected nearly at right angles to their former direction, and run under it from 50 to 100 miles, - _| Alluvium, Effect of causes now in action. _ Effect of causes now in action. Mud of rivers, deltas, gravel of torrents. ont Bo in England, but on a larger 1821.]> Gravel and rolled blocks, both on_ hills . andin. valleys,, not produced by any causes Now 1n action. Gravel of the valleys of the’ Thames, Se- vern, and Humber. | Blocks of Cumberland granite in the plain of Shropshire, near Bridgenorth ;. and . of Galway granite at Shalk on the SW _ 4of Carlisle, in Cumberland. ' "TERTIARY FORMATIONS, London and Hampshire basins. 1, Freshwater Limestone. ; Headen Cliff, Isle of Wight. a Wi London Clay. A Highgate Hill, London, ‘With plants‘and matine‘fish, Isle. of Sheppy- 3. Pastic Clay Formation, Clay, marl, sand, and gravel, with marine shells. al : “Basins of London, Hants, and Dorset. ~ 4. Puddingstone, of Hertfordshire.) * ghire; Wilts, and Dorset. S Lignite and Glance: Coal. Imperfect Wood Coal. Alum Bay. Isle of Wight. Druid. sandstone blocks “of Buckiigham-— Corfe Clay Pits. Isle of Purbeck. and:adjoining Parts of the. Continent. Sameas in England. Dilavium. ’ » Superficial. gravel, covering the regular Tertiary strata of the valleys of the Po, the Danube, and Geneva. Granite Blocks on the Jura above Neuf. chatel, and on the Saleve mountain hear Geneva: * a” TERTIARY FORMATIONS, Basin of Paris; Valleys of the Po, the Danube, and Switzerland. 1]. Calcaire d’ Eau Douce. Basin of Paris ; Frienisberg, near Benes ‘St. Saphorin, near “Vevey; Horgei near Zurich; Locle on the Jura; Vale ley of the Rhine, three miles NE of Basle ‘These are principally composed of marl stone, and containopeds of coal, with Freshwater shells intermixed. Oeningin, near Schaffhausen, with fresh. water fish. 2. Calcuiré Grossiereuf Paris, > Verona, Vicentine Hills, and Monte Be~ rici, in the valley of the Po. , a} Loretto, SE of Vienna, in basin of Da- nube. ; Tour de Moliere, Eof Yverdun, in Swit- zerland. ‘s ' ¢ With plants and marine fish. ‘ Monte Bolca, near Verona. nak Solenhofen, near Pappenheim (probably). : Fish of Mount Lebanon (probably). — 8.. Plasiic Clay. Formation, .. Beds of clay, marl, sand, and gravel, with ' marine shells. = Basin of Paris. ic: ite All the edges of the plain of Lombardy ; near Parma, Placenza, Asti, Turin, Vicenza. Valley of the Danube. Valley of Geneva and Constance. A, Nagelflue, of Switzerland, Como, and Salizourg. Puddingstone, of Rigi, near Lucerne, and of Bregentz on Lake Constance. 5. Lignite and Glance Coal. Perfeet and used for Fires, - Monte Bolcaand\ Arzignaniin the Vi- centino. Fussen in Bavaria. Titmoning, ‘Teisendorf, Miesbach, and all the coal pits in the Valley of the Da- nube, above Vienna. Marburg, in Styzia. Leoben, in Sty:ia. 464 Prof. Buckland on the Structure of the Alps, [iune, It is not implied that the above five subdivisional parts of the Tertiary Formations maintain the same relative order of succession in England ‘and on the Continent ; most of them probably alternate, but they are all more recent than the chalk of England, France, and Italy. SECONDARY Chalk. Large proportion of the SE of England. Green Sand. Large proportion of the SE of England. Oolite Formation. Coral rag, loose and rubly. Compact} beds of Com. Brush, Buckingham matble, Bath and Cotswold oolite. Lias, New Red Sandstone end Red Mart. , Great formation of salt aid gypsum. s Magnesian Limestone, - Yeovil marble. FORMATIONS, - > 12% | a Chalk, ? Craie of the French, encircling and form- ing the base of the Basin of Paris. Younger’ Alpine limestone of the Euga- nean Hills and Vicentine Hills, in Italy. Fort near Lunenburg, close to the town on the side of Hamburg. Castle of Cracow, in Poland. Craie Infericure of the French, Quader Sandstein and Plener Kalk, of Werner, Younger Alpine limestone of Savoy, form- ing the summit of the High Ridge from Mount Varens in the Vale of the Arve to Diableret, in the Rhone Valley. Jura Limestone (properly so called.) Younger Alpine limestone of Savoy, Switzerland, and Tyrol. Muschel Kalk, of Werner. Coral Rag. Same organic remains in a compact matrix, and used for marble at Roche, near Vevey. Compact limestone of Schaffhausen, lying above the Jura Oolite. Saltzburgh marble. Conte marble, of France. . Oolite of Jura, and Valley of ‘the Adige. Pierre a gryphite of France and Jura, full of the Gryphea Arcuata of Lamark, Muschel Kalk, of Werner. Bunter Sandstone and Roth Thon of Werner. , First and second salt, and gypsum forma- tion of Werner. — Greywacke of Brocchi in his Val di Fassa, of Ployer in his map of Tyrol, and of Yon Buch and Charpentier in their accounts of the salt formations of the Alps. [ Elder Alpine Limestone. Hochgebirgs Kalk Stein of Ebel, first Floetz Limer _ stone of Werner, divisible into. Zechstein (Calcaire_a Gryphite of Voigt and Schlotheim, and pepe Kuh phites aculcatus.) Asche. Rouhwacke. a Holen Kalk. Rogenstein. Stinkstein. — Kupferschiefer, or bituminous sii slate, with fish. These subdivisions are well known in the Thuringer-vald, and are occasionally | interspersed with salt and gypsum. 182k}. New Red bin tema Exétet encircling the base repipcaerne and . Metdip Hills. New Red Porphyry of Teignmouth,, An- trim, and Kinross. and adjoining: Parts of the Continent... 465 | Old Red Sandstone of Werner, Rothe Todte Liegende. Base of! Thuringerwald, | Schwanden, in Glarus., Lugano, in Italy. Red Porphyry of Botcen, in Tyrol, and of Chemnitz, in Saxony, ) This porphyry is associated, with, the New,Conglomerate. English Coal Measures, Newcastle, Der- byshire, Staffordshire, and South Wales, — Mountain, or Carboniferous, Limestone. Derbyshire, Alston, Moor, Mendip, South, Wales, subordinate in the: Great Coal Formation: usually’ found in its lowest regions, Old Red Sandstone. In‘its upper members: composed of loose ‘beds of red sandstone, red) marl, and. conglomerate. In’ its lower, regions passing insensibly into compact ‘ Wales the», frontier of England). and. es. : rs TRANS IT ION | Transition Sahwntene. Beds.of hideeatone occurring: heiecuaidy S in) the Upper Region of the Greywacke _Formation, , Dudley, Ludlow, Longhope, Titendilp." Greywacke. Passing into fine greywacke slate at one extremity, and into conglomerate at the other. Mountains of North Wales, Slate quarries of Penryn. Slate of Tintagel, in Cornwall, and top of “Snowdon, " in -Walés, containing marine shells.(Terebra tulites Py. Slate) of..Liandrindod, near, Builth, con-. taining trilobites. greywacke;: abundant Independent, Coal Formation. of Werner.. None in the Alps, or basin of Po. Potschapel, near Dresden. Friedland, in Silesia, and near. Tarnovitz, in Silesia... Namur, Saarre Brooke, St, _ Etienne in. France. Transition, Lime of Werner, and of Oesans lius d’ Holloy. Banks of the Meuse from Namur, to Liege; is of rare occurrence on the Con-— tinent. Variety of Greywacke of Werner. Seldom appearing on. the Continent.’ Occurs :at. Huy.on the Meuse. below: Namur, where. it lies .under.the mouns. tain limestone, The Vallorsine puddingstone is nearly of this age, but a little older. } FORMATION, _ Transition Limestone occurs dubohatuatity: in Greywacke, Thin beds: of it at Coblentz on the Rhine. In Bohemia near Prague. Wenlock-Edge, , Tarantaise, in Savoy. Banks of Rhine below.. Coire in Swise S of Werfen in Saltzburg. Greywacke. Same as in England. - Abundant on the Continent. Tarentaise, in Savoy. Matt, in Glarus. Slate of Blattenburg, in Glarus con ts ning fish and tortoises. Slate of Angers, in. France; containing. trilobites. a: sos of Killarney and St. David’s.. Conglomerate of Vallorsine. ew Series, VOL. 1. 26 466. = Prof. Buckland on the Structure of the Alps, [Junz, Primitive Rocks. - It may be useful to add to this table of geological equivalents.» a list of those alpine formations which most nearly resemblé each other, and which it is nevertheless very important to dis- tinguish ; e. g. there are in the alpine districts four varieties of - conglomerate, four of gypsum, and five of dolomite. ~__ Conglomerates, 4. 1. The most ancient of these conglomerates is ‘that of the: petit St. Bernard, the Vallorsine, and Tarentaise, being’ a ‘true® transition rock, and containing rolled fragments of granite, mica slate, gneiss, quartz rock, and primitive limestone. 2. The next in point of age is that of Schwanden and Mells near Glarus, and Mount Neisen on Lake Thun, being of the same era with the old red sandstone (rothe todte liegende) of Werner, and new red conglomerate of England. © °° \ 3. The third and most abundant conglomerate is that which, ~ - under thename of nagelflue and Rigi puddingstone, extends along ~ the line of junction of the Great Swiss Valley with the alpine limestones from Vevey on the Lake of Geneva to Bregentz on the Lake of Constance,.and thence continues onwards along the edge of. the plain of Bavaria towards Saltzburg. . This is_ the , most recent of the stratified rocks of this district, and is nearly — of the same age with the Hertfordshire puddingstone of Priclant, 4, The fourth, which is also called nagelflue, consists of agglu- tinated masses of diluvian gravel, composed chiefly of pebbles of alpine limestone, and not to be distinguished ‘but by:the cir- cumstances of its position from No. 3. It is usually found in the valleys, and in irregular patches on the lower hills, while No. 3 forms a chain of mountains from 3000 to 4090. feet high, which is continuous through nearly the whole of Switzerland. No. 4 abounds in all the diluvium of Switzerland, Tyrol, and Italy, : when the pebbles are calcareous. It should seem these pebbles have siitpplioal the cement by which they are held together, as the ravel is usually loose: when composed of any other substance than limestone. ! | a) Gypsum Formations, 4. In the same districts we have certainly three, probably. four, . formations of gypsum. 1. Primitive. 2. Transition. 3. Secondary. 4. Tertiary. 1. Primitive.—Existing in small quantities (if at all) in the Alps., Brochant and D’Aubuisson doubt whether there be here: any true primitive gypsum, and are inclined:to class that which has been considered primitive among the transition series. 2. Transition Gypsum.—Much of this occurs among the tran=: sition rocks of. the Pareitthise described by Brochant. It may, 1821.) and adjoining Parts of the Continent. 467 be seen also by the road sideat Charmey, between St. Michel and the Hospital of Mount 'Cenis, and also at the Hospital. of Mount Cenis. i Mik p@bd . enitasal 3. Secondary Gypsum.—Of the same age with the magnesian * limestone, and new red sandstone formation of England, this is: usually misealled transition gypsum by most writers on the Alps. It occurs at Bex and Leisigen in Switzerland ; in the salt mines of Tyrol and Saltzburg ; at Michell, 10 miles north of Trent ; and. Lovinio, near Menagio on the Lake of Como. Sista 4. Fibrous Gypsum.— Of tertiary formation, of the same age» with the Paris beds -occurs in .the molasse. of Switzerland,» near Yverdun; in’ Argovie, near Soloure; at Boudry, near: Neufchatel ; and St. Julien, near Geneva. ri Dolomite, Five Kinds. Sia {n the alpine regions there occur also five formations of dolo 1. Primitive—The primitive limestone ‘of the central - Alps’ often passes into the state of dolomite, of which a good example may be seen at the pass of Mount Brenner between Botzen and’ Inspruck.. -It{is here, compact, and interspersed with flakes of: talc, of a delicate green colour.. The primitive limestone also+ which forms the matrix of the great iron works of Eisentertz, in Styria, is in the state of dolomite... This.stratum is of great importance and extent in the Alps, and may be traced by its sparry iron ore from Lake Como to Eisenertz, and thence onwards into Hungary. sale ces 2. Transition,—I{ did not find. dolomite .in the few spots in which I had’ opportunity to see the transition limestone of the Alps; but as this formation abounds with magnesia in England, Russia, and North America, it is probable that it requires onl investigation to find it alsom the Alps. : 3. Lilder Alpine Limestone.—Dolomite prevails in no alpine formation so much as in this, which is equivalent to the grand magnesian limestone of England: it may be usually recognised by its pearly glimmering lustre. The soft powder that fills the cells of the rouhwacke and holen kalkstein is much charged with magnesia: as are also the strata of yellow sandy limestone that lie in the new red sandstone of the Vale of the Adige above Trent. oa ye rT In England, much dolomite occurs also in the mountain lime- stone. te be a 4. Younger Alpine Limestone.—Beds of dolomite minutely crystalline, and ‘of pearly glimmering aspect, abound in the oolite formation in the Valley of the Adige below Trent, and also m the hills on the west of Monte Bolca. In England, magnesia has been found in the oolite formation at Minching Hampton, near Cheltenham. It occurs also in the chalk of France. | 262 ' 468 . Proceedings of Philosophical Societies. (June, Ht. Tertiary. Formations. —The calcaire, grossier) of. ‘the. hills: that overhang the town of Verona, and of many parts of; the» Vicentine Hills, passes into dolomite. The loose calcareous’ sandy beds that alternate with this calcareous rock also contain esia. Marine shells in high preservation.are found both in’ the solid and loose varieties. - It may: be: useful. to, repeat concisely, what:has:already been stated more at large, that the following terms are applied indis-, criminately. by many writers on the Continent to: rocks which ought to be kept distinct; viz. greywacke to beds,of the new, sandstone formation, as well as to the true transition, rocks, « Transition limestone,;torthe » younger, alpine limestone, or English magnesian limestone formation, as well as to true tran- sition limestone. Mo . Transition gypsum, to, the saliferous gypsum, of the new red sandstone and magnesian limestone formation, as well as to that; which accompanies true greywacke. oh .|Pierre d gryphite to lias.. Calcaire a gryphite to. magnesian limestone. Jura limestone-to oolite, lias, and magnesian lime- stone. Nagelflue. to agglutinated, gravel, Rigi, puddingstone, andnew red sandstone conglomerate. iash ato ARTICLE X. Proceedings of Philosophical Societies.. ret ROYAL SOCIETY. — . May 3.—Observations on the Variation of Local Heat made among the Garrow. Hills, bens Scott, Esq. Ad On some Subterraneous Trees. discovered. near Mundsley, by Lieut. Miles, RN. | On the Enlargement of the Glands of the Neck, by J. How- ship; Esq. | | May 10.—-Some Remarks on Meteorology, by .Luke Howard, Re cuba on the Solat Eclipse of Sept. 7, 1820, by Mr. C. Rumker. May 17.—On the Anatomy of Parts of the Globe of the Eye, by. A. Jacob, MD, said | May,24.—Onthe Absolute Zero,, by Mr. Herapath. .1821.] Scientific Intelligence. ‘469 "if ; ARTICLE XI, “=< SCIENTIFIC INTELLIGENCE, AND NOTICES !OF !SUBIECTS. OD CONNECTED WITH SCIENCE, ‘I. Composition of Rhubarb. “Mr. Brande has lately analyzed the root of the Rheum Palmatum. “The results of the destructive distillation of rhubarb are ‘stated’ as follow: ih WEMROR RGA te Ware cree ec. 0 aie Pelee. mois ‘ Deke it AB coh die 10:0 Empyreumatic oil, gallicacid, and water, formed... . . 49°O Charcoal ....:.. eubvaw. ® URWOS Lak BIGAGTA Ji. . ii’ 8405 Phodpinatecot Tames U4. cdiias: 2 'bee ead oy auiaies il BIO + Ce Ok wad ce srbdewaeeed ih Z wpe. eV E RES Cece eecaeereseveerseeereertseeneeersece 0:3 1000 The component parts of rhubarb are stated to be as follow: " Water .. 3 250% ceene “ak gach ASIDE ICT PEE i SZ Cn os a ee So es Se cst svat wins <6) aan «SAM i estes 4.°3R0-. BONY Sc .. ne eee bad GR a a hid'o-wwdlncaid Sat bil Gh och » 100 Extract, tan, and gallicacid ..... 0... 6.0. nail. Soca ses 26:0 - Phosphate of lime............ PDB 1. Js bake hei O HMiiate Of Hime sre. ok cs lew eee fe haan ER 6°5 ‘Woody fibre. ......... WED ERS UA hace oes cleawees 16°3 | 100-0 Il. Rocks of Mont. Blanc. Owing to an accident, these rocks were not. quite correctly noticed -in Capt. Undrell’s communication. _ . ... The very highest rock is highly crystalline hornblende and steatite ; thelatter might be mistaken for compact felspar, but it yields to: pres- - sure and the knife. Another specimen which is laminated seems to consist of greyish and yellowish steatite, imbedding quartz crystals, and having brown mica between the lamine. This specimen might be _ readily mistaken for fine-grained gneiss. ‘The rock called Petit Mulet, ‘the specimen from which was mistaken for that from the summit, is.the _protogéne of Prof. Jurine, consisting of quartz, felspar,; and steatite. “Th. Granulation of Copper. The following singular circumstance was communicated to me. by Mr. W. Keates, of the Cheadle Copper Works. “I send you some globules of copper, quite hollow, and so light as to swim on «water; the history. of which is as follows: One of our refining furnaces contained about 20 cwt. of melted copper, which was to be laded into blocks; but the refining process had not been carried ..far enough, ‘so that when themen.came to lade it out into the moulds, they found it to be impracticable, in consequence of its emitting such ‘470 Scientific Intelligence. (June, a = quantity of sulphurous acid vapour. They were, therefore, obliged to put it into a cistern of water to granulate it, but by this operation, instead of the copper assuming the form of solid grains, the whole of it became in the form sent to you, and floated upon the water like so many corks. What is the most probable explanation of this henomenon ? One of our refining men, during 40 years’ experience in the business, bas never seen any thing similar.” To the above account, Ihave only to mF that the globules of copper sent to me, although extremely light, had lost their property of floating in water, but they floated in sulphuric acid. I do not venture to offer any explanation of the phenomenon.—Ed, — ) AV. Analysts of Indian Corn. . Dr. Gorham, of Harvard University, Cambridge, U. 8. has analyzed Indian corn. It. appears to contain a, peculiar vegetable substance, which the discoverer has called Zeine.._ The results of the analysis are as follow: . tin eked) od . . Common state, Dry, state. BRERA RS RRR reppin ti tielaes Aer 9°0 RRR tr Gale rs egnes Senge eninge 77°0 84599 y YY EER age a ar ig tasoeis plinidashch dite “hss SSR scuncie-e: ak Me PAM sc cade cco Ghee aces oh nae 4 SO ccte, Teer -.Gummy matter. ..... dvacedeceswouwe :: 1:75 ,... 92922 GSaccharine matter. 0. ee PA 1°593 Dbtractive, mattet 666655 od aS O8 . ...... BTS Cuticle and ligneous fibre............. 3:0 5. 0 8296 Phosp. carb, sul..of lime and Joss 1000. ...4 + 99°980 (Institution Journal.) V. On the Todide, Oxides, and Chlorides of Gold. According to M. Pelletier, who first obtained the iodide, gold is not acted upon either by iodine or hydriodic acid; but the hydriodic acid - containing iodine easily dissolves gold, and especially when a little “nitric acid is added; the iodide of gold then ‘formed is a brilliant ~- Ce and apparently a crystalline powder. lodide of gold may ‘also e procured by causing hydriodic acid to act upon the ‘oxide of gold, or by adding hydriodate of potash to chloride of gold. ‘The properties of the iodide of gold are, that it is insoluble in cold water, and very “ sparingly soluble in hot; when put into concentrated and boiling nitric, muriatic, or vgs bes it is decomposed, the iodine being evolved, and the gold dissolved. It is also decomposed at a tempera- ture of about 300° of Fahr. and by the alkalies in solution. It is . . stated to be composed of i; Loding .2ii:9 ..a0Gaa ta walad sin setae Bh Gold 0. de side. Be oy eiseiss cathe .. 66 : 100 — The composition of the oxides and chlorides of gold is stated as follows : [iit 9G.09 JI BiMOL Y! 1821.) New Scientific Books. ‘471 (+ 10 oxygen, protoxide. +° 30 oxygen, peroxide, + ‘44 chlorine, protochloride. | Gold 299 + 132 chlorine, perchloride. M. Pelletier draws the following conclusions from the various expe- riments which he has made on this metal. 1. Gold ought to be considered as an electro-negative metal, 7. e. as ‘a metal forming oxides, which tend rather to act as acids than as bases. 2. The oxides of gold cannot form true salifiable compounds with the acids. : “8. The peroxide of gold will unite to the alkalies and’ other metallic - oxides, forming combinations which possess peculiar properties. »4« Gold in solution-in aqua regia 1s in the state of perchloride, and ‘the supposed triple salts of gold are only mixtures in which the gold is still in the state of perchloride. 5. Gold unites to iodine, forming a compound of which the propor- - tions are’constant, and easily determinable. 6. According to the proportions of the iodide of gold, those of the oxides and chlorides may also be ascertained as given in the Mémoire. 7..The vegetable acids and salts have different actions on the chlo- ‘rides and oxides of gold. Amongst them may be distinguished the - oxalic acid and the oxalates, because their action is very peculiar, and supports the opinion of M. Dulong on the oxalic acid.—(Annales de Chimie et de Physique.) Articite XII. NEW SCIENTIFIC BOOKS PREPARING FOR PUBLICATION. ~ "The Parent’s Medical and Surgical Assistant, intended for the use of ‘the heads of families, parochial clergymen, and others, by Thomas i Ayre Bromhead, MB. Christ’s College, Cambridge. Dr. Paris and John 8. M. Fonblanque, Esq. Barrister at Law, have, ~-in considerable forwardness, a work, to be comprised in one volume, ~ 8vo. and entitled “ Medical Jurisprudence.” It will comprehend ~ medical, chemical, anatomical, and surgical investigations, applicable to forensic practice, for the instruction and guidance of coroners, “magistrates, counsel, and medical witnesses, with a copious appendix ~ engravings. of statutes, cases, and decisions. elie a “Mr. Gideon Mantell’s Outlines of the Geology of the South-eastern Division of Sussex, will soon be published in royal 4to. with numerous A Treatise on Scrofula, its Nature, Treatment, and Effects; also, * the alteration produced by it in the structure of all the different parts of the body, with special reference to its connexion with spinal curva- ’ ture, diseases of the joints, affections of the glands. To which is ~ added, an Account of the Ophthalmia, so long prevalent in Christ’s ‘ Hospital. By E. A. Lloyd, RCS. .&c. &c. in one volume, 8vo. ‘This Work obtained the Jacksonian Prize in 1818. 472 | \New Patents.” June, Dr, Dickinson has in the press, The,Medical Student’s Vade Mecum; being a work in the form of question and answer, comprising anatomy, physiology, botany, and pharmacy, &c. To which will be added, an an. and correct Explanation of the Chemical Decompositions, intended principally for gentlemen previous to their examinations at ‘the Surgeons’ and Apothecaries’ Hall. | | 70129 JUST PUBLISHED. ' Flora Scotica,. or a Description of Scottish Plants, arranged both ‘according to the Artificial and Natural Methods; in two Parts, By W. Jackson Hooker, LLD. FRA. FLS.&c. 8vo. 14s. , A Treatise’ on the Hydrocephalus 'Acutus, by’ Leopold.Anthony Golis. . Translated ‘fromthe German; by Robert Gooch, MD. 8vo..&s. Observations on the Derangement. of the Migessixe Organs, » and some Views of their Connexion with Local Complaints, | By W. Law, Fellow of the Royal College of Surgeons, Edinburgh. - 8vo.. 6s. »A. Toxicological | Chart, exhibiting at one View..the ‘Symptoms, Treatment, and Modes of detecting the various Poisons, .Mineral, Vegetable, and.Animal, according to the latest Experiments. _ By W. Stowe, RCS.-London. . 1s..6d. - A. Treatise on Indigestion and‘its 'Consequences, called Netvous and Bilious Complaints, with Observations on the Organic. Diseases,’in ~which they sometimes-terminate. By. A..P.,Wiison Philip, MD.FRS. “&e. -8vo0. 9s. ArtTIcLe XIII. NEW PATENTS. Stephen Wilson, Esq. of Streatham, Surrey, for improvements in machinery for weaving figured goods ; partly communicated to him by a foreigner—March. 8,182]. : --Henry Browne, of Derby, chemist, for an improvement in the: con- struction ‘of -boilers, whereby.a saving in fuel is effected, and smoke rapidly consumed.—Marelh 16. | -Llario Pellafines, of Earl’s-court, Middlesex, for ‘certain new and improved machinery and methods for breaking,. bleaching, preparing, ~ manufacturing, and spinning,.into. thread or yarn, flax, hemp,..an - other productions and substances of the like nature, .capable of: being eeeealactircd into ‘thread.or yarn.—March 27. ‘William. Southwell, of Gresse-street, Rathbone-place, for certain improvements on cabinet piano-fortes,—April 5. James Goodman, .of Northampton, for an improvement on stirrup- ‘irons. April 5. : ‘ds 4 r exces | Henry Goldfinch, of Hythe, Lieutenant-Colonel in the Royal_Engi- neers, for’an improvement inthe formation of horse-shoes.—April 5. William Annesley, of Belfast, architect, for certain improvements .in . the construction of ships, boats, and other vessels.—- April 6. ‘William Chapman, of Neweastlesupon-Tyne, civil engineer, -for. a ‘method ‘or methods.of transferring the ladings of lighters and barges ‘into ships or-vessels, or from ships or vessels into lighters and:barges. —April 12. 1821], Mr. Howard's: ogical Journal... An ‘ARTICLE XIV. METEOROLOGICAL ‘TABLE. | _ |Baromerer,| THERMOMETER, >of Aiygr. lat 1821, - | Wind. | Max.| Min.| Max. | Min. | -Evap. | Rain.| 9.a.m,,. th Mon. , . 4 © April I] W |29°60/29'34) 51 | 43 ea LY WO dint iQ] PW °429°S4129'°26]" 58°" 38 BSP OTA hw® 8B) W °f29°38/2931) S12 STL 01]. 624)" AIN W/29°48/29°30) 5550} B40 [i | G4 5IN W/{30°07/29°48) 52 .} 531.) | «60 6|N W{30:07'30'03} 49 42 55:| 10] « «56. 7\IN W(30°14'30°03| 59 48 — 92 8| W_ |30°14/30°05} 67 43 — 59 | 91S W)\30'05/29 86} 65 AA, 32 81 1¢ 10iIN W){29'80\29:72! 64° | - 47 — | — 68 11S W(|29:72\29°46, 61 | 41 —_ 23| 67 12}: W |29'46'29°38} “54 | ° 88 — “60 13] W |29°65\29'47|. 54 36 — 02; 62. 141 S_ |29°53/29°36} 51 37 woe | Ad Oe! 15S. W/29°54/29'48) 54 30 —»4|-03] 68 16} Var. |29°48|29°43} 59 27 — 61 17\N —-W/|29°66)29°48! 58 38 _—_ | _— 58 1Q ASIN W/{29°83|29:66)..51>.). 40.) — 06} 63 19S W/29'74,29°61| 57 |. 48 40; 36) 70 20IN- Wi29'80\29'61| 65 | 42 |>— | 12] 79 21) N_ .j30°01/29°80}, 59. | « 42 meio 81 22IN E/30°02\29'62) 59 Ad —_ 73 23}, E |29°62,29°45| 70 50 ‘80 }°04) °98L: 2418 W{29°67 29°62} 70 4.2 — ' 68 25, E 29°75 29°67 74 44 — a 64 | p DQG) «B+ 189" 75/29" 71} °78 48 — |= 63 27) W_ (29°84,29°75 678. |¢ AD otf Mi] oF 69 28) N_ |29° 86,29 $4) 71 A3 —- 61 29| .N . (30:05 29°86 63. .4 » 47 mf | SOS 30|IN E/30° wedi 05| 51 45 25} O1/ 67 jintesinl nse me {30° 14.29: 261 78 27 2°91 | 1°52 92-56 The stiservations i in each line of the table apply to a period of twenty-four hours, beginning at 9 A.M. on the day indicated in the first column. A dash denotes that the result is sincluded i in the next following observation. des ’ “474 Mr? Howard’s Meteorological-Journal. (June, 1821. REMARKS. Fourth Month,—1. Fine: rain at night, 2. Showery: windy. 3. Squalls, with hail and Nimbi, 4, 5. Fine. 6, 7. Cloudy, 8. Very fine: thermometer 63° at half- past nine. 10., Cloudy:/some appearance of thunder, p.m. : lunar halo. 11. Cloudy: windy. 12, Showery: gusty: at Tottenham a heavy hail-storm, 13. Slight showers ; gusty. 14. Showery: windy. 15. Ditto: at Tottenham thunder was twice heard to the N, there being at the time many large Nimbi, and the first swallow made its appearance. 16. Fine: a hoar-frost in the morning. 17. Hoar-frost: thundered twice at half-past four, p. m, 18, ‘Showery : frequent rainbows during the afternoon ; 3 one was observed with two complimentary bows at some distance beneath it, 19. Showery: boisterous night. 20. Slight showers during the day: very frequent lightning in the evening : a thunder-storm about seven, p.m, : the lightning extremely vivid, and nearly continuous from SW to SE, and much forked : some flashes descending perpendicularly ‘to: the-earth. 21, Cloudy: clear night: swallows now numerous, 22. Very fine morning. 23, Fine: some lightning at night. 24. Very fine. 25. Ditto. 26. Sultry day: incessant lightning in the evening, which continued nearly all night in every quarter of the horizon, and very distant. -. RESULTS. Winds: N, 3; NE, 2; E,8; 8, ls SW, 5; W, 1; NWy8; Ver J Barometer: Mean height : | 44 For the Wiiomth.:. 3. osceuses pers. ray seeceeees+ 29°697 inches. For the lunar period, ending the 25th... seeaseee eeeee 29-615 For 14 days, ending the Ist (moon south). ..... feooee SO5Z1 For 13 days, ending the 14th (moon north) ........... 29°675 For 14 os ending the 28th (moon south).,..... e.. 29°689 Thermometer: Mean height 2 eee! . Bah For the month... ./s.sseeseescseeeeeees eet coccag ee SO40° For the lunar period... dence ie ieniiaiiunt Na Mu 48-400 sda seunde, the nin in Arie... -.-..+ so... ese» 45°633 Wiepenttlens tec; ci «« osc cesuiite ee ae te ea eee eee eeeaee 2-91 in. ig eR igh ne al thie , i i ee 1°52 _Mean of hygrometer. ......... adasese coasecesesonssvcesvesvevedes-Olm “Laboratory, Stratford, Fifth Month; 21, 1821. --R. HOWARD. INDEX. AH vy », ARRON composition of, tat composition of, 327. i-———— nitrous, composition of, 326, . Adams, Mr. J. on a method. of ap- plying .Maclaurin’s theorem, 98— -© ‘on the expansion of the functions f (x), S (@y), &c.. 339, "Alkali, new one in the atropa belladonna, 263. Ammonia, bicarbonate of, on the, 110. Ammoniacal alum, on, 72. © Analysis of Indian corn, 470. . Apparatus: for the discharge of ordnance, .. description of, 89. .. Arseniate of soda, composition of, 13. « Arsenic, atomic weight of, 15. ———— acid, on the atomic weight of, 13. composition of, 15. Arsenious acid, composition of, 15. Astronomical, ‘magnetical, and ’metcorolo- gical observations, ‘by Col, Beaufoy, |. 76, 156, 263. Atmosphere mercurial, on, by M. Fara- day, 153. » Atomic weight of strontian, lime, mag- . hesia,. phosphoric acid, and arsenic acid, |. Atropium, on the properties of, 263. ————- sulphate of, composition of, 264. oy + muriate of, composition of, — 268. ' Azote and oxygen, on the combinations of, BR. Azote, deutoxide of, composition of, 325. ——--— protoxide of, composition of, 323. ~ B. | Barytes and strontia, test for, 72. « Beaufoy, Col. astronomical, magnetical, and meteorological observations, by, 76, 156, 263=-summary of the magnetical and ‘meteorological observations for three years and nine months, 94—~on = the going of a clock with a wooden pendu- lum, 203—table of the diurnal variation of the magnetic needle at Zwaneburg, in Holland, communicated by, 205. Beche, Mr. on fossil plants found at the Col de Balme, 67. pen se geology of the north-east border B24 of,. 149, . Birkbeck, Berzelius, J. researches into the com: tion of the prussiates, 219, 301, 433. . Bicarbonate of ammonia, composition of, 110. ; a.2 Mr. W. L, on a new method of constructing geometrically the cases of spherical triangles, by a develope~ -ment of their parts in plano, 259 Blowpipe, hydro-pneumatic, description of a new one, 428. Books, new scientific, 74, 154, 237,.317, ATL. Bostock, Dr. on whale oil, 45. - Brandes, M. on atropium, 263. Brande, Mr. on eC mI BR rhu- barb, 469. Buckland, Rev. W. on the structure of the Alps, and adjoining parts of the Continent, and their: relation to the secondary and transition rocks . of England, 450. urney, Dr, W. on the new comet, 298. C. . Calder Side, remariinble stratum of lime- stone at, 23. Caloric, radiation of, 81. . Carbon, chlorides of, discovery-andpro- perties of, 65. Carbonate of lime, composition of, 6. _ Carbonate of potash, composition of, 6. Cassius, purple powder of, on the, 393. Chemical philosophy, researches. into. the mathematical principles of, 81. -. Children, Mr. analysis of his essay. on chemical analysis, 140. Chloride of strontian, composition of, 5. Chloride of barium, composition of, 8. _ Chlorides and water, on the action of, 27. - of carbon, discovery and pro- perties of, 65, Chlorophzite, a new substance found in Rum, by Dr. Macculloch, 151. Chromate of lead, on the Pe maa eae to silk, &c. 72. Chrome, sulphuret of, on the, by M. Lassaigne, 153. _ Clarke, Dr. address: read at the Cam~- bridge Philosophical Society, by, 229 '—on the purple powder of Cassius, on the gas blowpipe, 419, 476 ae Circle, tangent to, new method of draw- ing, 44. Clinometer, new one, description of, 43. Clock, with a wooden mea es on the going of, 203, Cobalt, sulphate of, composition ‘of, 251. ——— on the atomic weight of, 951. Col de Balme, ay! cs ts found at, 67... Cold, artificial, on the production of, by Dr. Macculloch, 153. -Golebrooke, Mr.-on: the ‘geology of the “north-east border’ of Bengal, 149. -—- ‘on the geology of India, notice of, 390. ? on the valley of the Sut- oleig. sivdindsithen Himalaya, 88, _ Gomet,on the new,’ 298. Compressibility of water, observations on / Mr, Perkins’s account of, 135. 6 - on'Mr. Perkins’s account of, 222, Conite, anew substance found in Mull, by Dr. Maceulloch, 152. Conybeare, Rev. J. Sod substance «found ‘in» ironstone, 186 —on the red rock marle,. or newer red osandstone, 255, ‘Copper, acetate of, analysis of, 417. ——— on the atomic weight of, 243. bisulphate of, «composition of, of red oxide of, . 243. o_O by heat, 150. granulation of, circumstance at- tending, 469. ——— perchloride of, composition of, 245. quantity of, raised. in et Corn, Indian, analysis of, 470. = ‘quantity of copper raised in, Crystals, dissection of, 397. Crystallization of red oxide of copper by heat, - 150. -bodies, action of, on homo- geneous light, 115. _ Cyanuret of potassium and iron, ‘composi- tion of, 435. ~ iron and barium, analysis of, AAT. ea lead, : analysis 4 of, AAT. 2 -) a9, uae: eg was 1 Daven Mr. R. on rain-guages, 111. Davy, Sir Hs address of, on taking the chair of the Royal Society, ‘144, ~ Deuchar, Mr. John, on an apparatus for . discharging ordnance, 89—experimente reply to deltas" ionofanew . Index. on flame, with an apparatus for dis. charging ordnance, m4 206. Deuchar, Mr. J. on the application of Howard’s fulminating mercury to the Mischarge of ordnance, 449, ~ Dinsdale, Mr. on the dry rot, 45. Dollond, Mr. G. notice of his improved micrometer, 149, » on the physiology of the, 351. ote ty, observationson the Franklinian nsotaea of, 18h. . magnetic experiments, 137. — __Electro- , /Maeneraaney Bees B. researches into the: ma- thematical principles of chemical philo- x mpliy, 7 Bh. a Faraday, M. notice of the properties of the mage one and a triplecom- pound of iodine, carbon, and hydrogen, discovered © na mercurial: “at. mosphere, by, 153—on the dissection of ‘crystals, 397—experiments on» a_ substance obtained during the distilla- tion of nitric acid, 217. . Finland, new ininerals from, 233. ‘Flame, experiments on, 206. (g Forbes, Dr. on the comparative tempera- ‘ture of Penzance, 293. . Forchhammer, Dr. on the preparation of pure salts of manganese, and ‘om ‘the composition of its oxides, 50, a. ‘Gas, from oil and coal, on the comparative advantages of, 209, 300, 383, 431. Gas blowpipe, observations on, 419. Galvanic apparatus, description of anew, 329. 5 new one described, 329. Geology of India, introductory essay on the, notice of, 390. - Russia, outline of the, notice of, 391. Giddy, Mr. E. C. register of the weather of Penzance for 1820, 297. Gold, on the iodide, oxides, and chlorides, ‘of, 470. Gorham, Dr. analysis of Indian corn, 470. - Gosport, meteorological journal kept at, ean HL Pr Hamel, Dr. account of two late attempts Index. 4 ascend... Mont-Blanc, extract..fromy Sei Mr. Ht meteorological. observae- tions, &c. at Manchester, ¢95... Hanstein, Prof.. analysis of his researches: on the magnetism of the earth, 139. Hare, Dr. on. a new: galvanic apparatus, . theory, &c.. 329. Hatchetine,. a. new: substance found . in ironstone, description of, 1,36. Heat, mathematical inquiry .into the causes-and phenomena, of, 273. Heaton, Mr. J. results of a meteorological rain kept ah tanpensiens in.1820, by, 2742 Henderson, ‘Dr. on fax snows) 43.: Henry,;Dr. analysis,of ,a, native, carbonate: f of magnesia, 452. charcoal and hydrogen, 228. Herapath, ‘Mr; J..mathematical. in quiry: into the causes,’ &c./ of heat; ears, &ea- 273, 340, 401. Herschel, ‘Mrs: Js FW. on, the action, of: crystallized’. bodies., on, homogeneous “light, 115,:161—on, the; separation. of iron from. other: metals, 389. Hop, experimental sii ob into. the opro- perties of, 194. ©. Hope, Dr. remarks on Mr. Phillips’ § ana- lysis of the Pharmacopeia-Collegii Regii’ Medicorum, Edinburgensis,’ 187. Howard, Mr. R: meteorological table, by, 74, 159, 239, 319, 399, 473. Hydrocyanate of iron and copper, analysis of, 448. cobalt, analysis Hydrocyanates,' ferruginous,. researches: into the compositiomof, 219, 301, 433.’ I. Jack, Mr. Penang, 71. Indian corn, analysis of, 470, Iodine, carbon and hydrogen, notice of triple compound of, 66. Iron, on the atomic weight of, 247. -——— protosulphate. of, composition of, 248. ole its separation from: other: metals, 38 Ironstone, ona new: substance found in, 136, Iridium, reduction of the salts and oxides of, 424, Ives;« Dr. experimental inquiry into: the chemical properties, &c. of the hop, 194, ' Julin, M. ona peculiar substanceobtained during: the distillation: of nitric: acid, 216—notice of minerals from Finland, "by, 233. —~ on the neriform: compounds of : W. account of the island of | 477 ~Reacistenaate Yat Lite Kater, Capts-remarks:on- his’ e iments on the length of the pendulum;:387%:) ” notice of a lunar,volcano, 228, ». Keates, Mr. on a circumstance.atte the granulation of copper, 469. Kinfauns Castle, metoaeolngien! jommial kept at, 372.. ¥ an” Li yin LT tsenane ‘M. on the lion v9 chromate of lead. ‘tonosilk; | &d. » Sodan on.thesulphuret of chrome, 153) °° - gs en's in toadstone; ‘account of;’ Oe: © t, homogeneous, actiom of cyst lized bodies on, 115, LOEZ Lime, on the:atomic weight of, 26on the solution and: crystallization of, 10%, Sd hasta of, dissolved’ by~- water; Limestone, remarkable stratum of, at Calder Side, 23. Log line, on a machine for mpaenring 4 a ship's) way by, 113,208.» Lupulin,. peculiar: substanee'contained in. =e. BoP ADA, gi" } Maceulloch, Dr. rie ag of tweiitihe substances found in Rum and Mull, 151—on the prodiiction of artificial cold, 153. remarks on: quanti rock, Macias’ 's theorem, 1 method of applying, Magnesia; on: the atomic. weight of; 8. native carbonate of, waste of, “52> ‘ hative hydrate: of, notice: 0 395. f Magnetic needlé, diurnal variation, of,” at Zwaneburg, in Holland, 205. Magnetical and: meteorological: ‘observa- tions, summary of observations for three years and nine months, by Col. Beau- foy, 94. Magnetimeter, results of _ experiments made with, 396. Magnetism of the earth, on: they 29, Malvern’ Hills, geology ‘of: 16. . Manchester, meteorological observations at, 298) Manganese, on the preparation of ‘pure — and composition, of the: oxides: “ me carbonate of, pimapenitinins of, 54, rouge of; “composition of, 249.) _on the atomic weight of, 249, 478 Mercurial atmosphere, on a, 153. Mercury, fulminating, on the os. of; to the’ of ce, 449.) eteorological tables, by Mr. R. Howard, 79, 159, 289, 319, 399, 473. ton, 138, QI2.° Castle, 372. Micrometer, improved; notice of, 149. Minerals, new, from Finland, hotice hos ‘ 283..id0» intelligence, 236. : Mont Blane, account of two late attempts to ascend, extract from, 33, summit of, 3T3y. M wat et on “sro . uriate composition -strontian, ‘composition of; 6:-— N. Mies ona ‘audethine! £0: meastire a "8 way by the log line, 208... TE | Ni on the atomic weight of, 250.: Nickel, sulphate of, composition of, 250, Nitric acid, on a! ar substance - obtained ‘during the distillation of, fie SkVe-wt to ‘ Oil and: coal. gas, on;:209, 300, 383, 431. Oil, whale, on, 45. Ordnance, .on .altcapparatus for. discharg- ing of, 89. Osmium, reduction of the. salts and oxides. of, 4245 a6. Oxides of manganese; ion of, Ble ‘compositi Oxygen and azote, on the compounds of, 322. Oxymuriate of potash, on mixtures of,. for arging sau 202 P, Palladium, reduction of the ‘salts and oxides of, 424, Paris, Dr. Pharmacologia, analysis of, 223, : on the physiology of the egg, 351. Patents, new; 715, 155, 238,318,398, 472, pha ye M. on the Yodide, oxides, and ld, 470, my on “ty comparative temperatirre of, 293—register of the weather at, 29T. Perkins, Mr. on compressibility of water, *- journal kept at New Mal._ — ‘kept’ at’ Heaton, kept at Kinfauns 3 an. account of an: ascent to the [ . Index. oe or the orem a substances, &c . i 223, ae ‘Medicorum Edin- ~h of, 58. ay ° ‘ ips, Mr. W. “thorns of the* M vern Hil, 6 and water, 27—on wligheays of as ane to dEHnite the seetipartee solutions: of oxymuriate of lime, ‘T2 —on the solution and ation of” lime, 107—on’ the bicarbonate’ ‘of ammonia, 110— ents on a- substance’ obtained | g the distilla. tion of nitric acid, itn tt oe z. verdigris, 4172" Phosphate of lead, cdinpisition of; | ———-—— lime, composition of, 12, » Fear acid, on the atomic weight of; Pliny, sed veiow"asiantenda by) 49fiocasail Pratt, Mr. 8. P. bearer. dr of a new clinometer, 43. Protit, Dr. reply to Dr. Yelloly’s ferivavis on the’ estimate’ of mortality from ume operation( of lithotomy, 426.. Prussian blue, pregealeinnss aes anid, ~ analysis of, 440." Prussiate of Mya 1 and iron, composition OF; ASSL Prussiates, igeveavelsos: ined “the dornipesi- tion of, 219, 301; 433... Pyrallolit; |a anew mineral rity : Finland 234, ve Fer (94903. NUS a bilge Quagga, and.ass, hybrid, bred from; 64, ! Quartz rock, remarks ‘on, 67. . OR, Radiation of caloric, 81. or on the fall of, 45. - Rain-guages, on, LIT. Red rock marie, on the, 255. efi Red sandstone; >newer, on the, 255.: - Rheum palmatum, composition of, 169. Rhodium, reduction of the salts and oxide of, 424. Ricardo, Mr. on the comparative advan- . tages of oil and coal gas, by, 209—fur- ther observations on ditto, by, 383, Riffault, M. on ammoniacal alum, 72. Ritchie, Mr. ‘on a new method of drawing a tangent toa circle, Roget, Dr. on ae Perki Bes e compressi water, fe , Romanzovit, a oni from Finland, 233. ‘ Rot, dry, on, 45, s’s account of Index. } Ss. Salts of manganese, preparation of, 51. Scoresby, Mr. results of experiments made with his magnetimeter, 396. =~ Scudamore, Dr. analysis of his chemical and medical report of mineral waters, 308. Smithson, Mr. J. on some capillary me- tallic tin, by, 271. Snow, red, 43. Society, Astronomical, of London, pro- ceedings of, 313, 392. Cambridge Philosophical, address read at the first meeting of, 224. Royal, proceedings of, 64, 144, 227, 312, 389. wit Geological, proceedings of, 67, 149, 312, 390. Spherical triangles, new method of con-~ structing the cases of, 259. . Stockton, Mr. meteorological journal kept _ by, at New Malton, 133. Stokes, Mr. on lead ore, in toadstone, 67. on a recent deposit of com- pact limestone, 71. Strangways, Hon. W. I. H. F. on the geology of Russia, notice of, 391. Strontian, on the atomic weight of, 5. and barytes, test for, 72, Sulphate of indigo, as a test to determine the strength of solutions of oxymuriate of lime, 72. _ -__—— magnesia, composition of, 8. --———- — manganese, composition of, 53. -—————. soda, composition of, 5. Sulphuret of chrome, preparation of, 153. i" T. Tangent to a circle, new method of draw- ing, 44, Taylor, Mr. on the Calley copper mine in Scotland, 70. Theorem, Maclaurin’s, on a method of applying, 98. Thomson, Dr. T. on the true. atomic weights of strontian, lime, magnesia, phosphoric acid, and’ arsenic acid, 1 —on the true atomic weights of copper, . 479 zinc, iron, manganese, nickel, and. cobalt, 24]—observations on the — on of azote and oxygen, Tin, on some capillary metallic, 271. Toft’s blowpipe, description of, 419. Triangles, spherical, on a new method of constructing the cases of, 259, Trimmer, Rev. H. S. communication from, respecting Mr. Herapath’s expe. riments, 417. U. Van Marum’s memoir on Franklin's rg of electricity, observations on, Verdigris, analysis of, 417. Undrell, Capt. J. account of an ascent to the summit of Mont Blanc, 373, Volcano, lunar, notice of, 228. WwW. Water and chlorides, their action, 27. ——-- corepressibility of, on Mr. Per. kins’s account of, 135. Whale oil, properties of, 46. Woolf, M. N. notice of two steam~-en.« gines erected by him, 236. ¥ Yelloly, Dr. on Dr. Prout’s estimate of mortality from the operation of litho- tomy, 363. reply to his remarks on Dr. Prout’s estimate of mortality from the operation of lithotomy, 426. Yule, Col. on an apparatus for the dis. charge of ordnance, 89. Z. Zinc, on the atomic weight of, 246. —— sulphate of, composition of, 247. Zirconia, process for procuring pure, 74, END OF VOL. I. C, Baldwin, Printer, New Bridge-street, London. 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