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MU tg ei tte gb bia a peat PM] " Si h.iotnie beaerenh veyigh * ‘ LMR a VU Ae a Bad Meare ' ‘ Vides ROW ATH Mme gi : , EMD ected tere eBoy Searee bey Meese Aisle, kote koe ve " 4 FLUNG The Le pn be rar het bed ere b ' : Mts Vb tee ee eh eee eh Re bee Ye j : WPA DED aD PE PEE AND babe meee yy) i back FA ad we ee ee Hed Se SEN go deed Fhe eben Ape BR ar May EMR SES WO RO i A Mie Ste NT SL ayan ‘ Ped pe nas Ney ee Mee be pee gs OR £34 PUY PP oP Ma OR aly sg ate eee: rs tena “ty Hye poene Ve ere dot & ees a hy poh eee na hea yt ava ree) aes. ean aA SSE ” yey i Hau ae Rein cel : SN aie bite arisen WOE ea ia ine Uk iiahe rene tattle bul GARRY abi asks RRL Boueieatngss a) ; Aer oud rbd Wh Veaie ede tye tela i WWephits? eo Dae sy Beith bank an ) i en sep rarely ' “4 tVeyenne shay ee Wert shetactand at L } RP a's) a bhatt aaa. hos a rr Pr wes Pai airer Fe es : : i CeCe RE iat ‘ vt F Hv hee beh PO pnd oth A F Ypa's Peete Vai ‘ fy i : ia beaa bite dralarpedeqeaeih ‘ rates BTR Reis Wie tte? 1 2 ban ‘ See eet] evan’ wor é . " Peis ee i Noe eden ed dei ‘ io eho eed cA Aes Gay ie rie be DONTE ‘ te doy ia eat enw 1 . n, ; Aguas Bi bar w ded ‘ a he ‘ tae i ' “i 3 ROE ETC NRAN ia | ct F unt pe ah Pel Waldo i ; { yh hae et ae ‘ Not ; ¥ besa eit Layee Me nk pe mes rere Renter eta os " a rade sis s oa vig 4 a) CLA baad Pa nee 5b od < ma ‘ Viniey SORA IE Pe a 4 an 1 \ NaC RL al PGR, te ; a ‘ fan et y ee ' SCA ear ire eG Cond Beiaayst dita oe) ; ‘ vad t en ea! Perse ta ae Br Tay te ‘ wa ae | badaaae i Vea ail 4 ’ vy “ed ey i WAAR eae g ‘ CSN ae Oe a SOR EMER Un ; iB Vode ts Wests Pen ala te SRR Re eRe REE eh selih Her Sy artesian test ' ata bea TN tere iced a ie Re bia ‘ 14 oye Vo Gat uhenh aba a ‘ stress a a SCIENTIFIC PROCEEDINGS OF THE ROYAL DUBLIN SOCIETY. dete Series. VOLUME IX. DUBLIN: PUBLISHED BY THE ROYAL DUBLIN SOCIETY. LONDON: WILLIAMS & NORGATE. 1899-1902. 3 218934 2 ON; se THE Soctery desires tt to be understood that it is not answerable for any opinion, representation of fucts, or train of reasoning, that may appear in this Volume of its Proceedings. The Authors of the several Memoirs are alone responsible for their contents. Printed at THe UNIvERSITY Press, Dublin. ae 1 CONTENTS. VOL. Exe ACR PAGE I1.—Corallorhiza innata R. Br., and its Mycorhiza. By A. VaucHan Jennines, F.L.S., F. G.8. -, and Henry Hanna, M.A., B.Sc. (Plates I. ‘and II. ), 5 1 II.—Mining and Minerals in “the Tishaa na Se aetaniae By KE. St. Joun Lyzurn, M.E., A.R.C.Sc.1., F.G.S. (Plate III.), 12 IIJ.—A List of Irish Gomiinacon, By T. Toon D.Sc. (Lond.), F.L.S., Professor of Botany, Royal College of Science, and Keeper of the Botanical Collections, Science and Art ae Dublin; and Miss R. Hensman,; . : - 22 V.—Notes on a Method of comparing the tates Opaeiies of Oraatie Substances to the X Rays. By Ernest A. W. Hentey, B.A., 31 V.—The Kisselguhr of Co. Antrim. By James Hotms Pottox, Bice 33 VI.—On the Correction of Errors in the Distribution of Time Signals. By Sir Howarp Gruss, F.R.S., Vice-President, Royal Dublin Society. (Plates IV. and V.), 5 5 37 V1I.—Proposal for the Utilization of the ‘‘ Marconi? Sten of Wire- less Telegraphy for the Control of Public and other Clocks. By Sir Howarp Gruss, F.R.S., Vice-President, R.D.S., . 46 VIIJ.—On a Hydro- Dynamical Hypothesis as to Electro- Magnetic Necons By Pror. Georcr Francis FrrzGerarp, F.R.S., . 50 IX.—Note on the Results that may be expected from the sioposed Monster Telescope of the Paris Exhibition of 1900. By Sim Howarp Gruss, F.R.S., Vice-President, R.D.S. (Abstract), . 55 X.—On the Concentration of Soap Solution on the Surface of the Liquid. By Davin Henry Hatt, B.A., : : 3 56 XI.—The Rio del Fuerte of Western Mexico, ci its Tauterien By Kinstry DrypEn rete M.A., Assoc. M. Inst. C.E. iad WAS COVE vas : 60 XII.—Note on Improvements in fis Mean: of causing Oasnetore or Flashes in Buoy Lamps and Beacons in which the Lights Burn Continuously for a month or a longer time. Py Joun R. Wicuam, M.R.I.A., ° 2 76 XITI.—Survey of that Part of the Range of iene s Omerations cio Man is: competent to study. By G. Jounstone Stoney, M.A., D.Sc., F.R.S. (Figures 1 to 6 Glas (Plate), 1.) ee) XIV. Tee of the Boyle Medal to Grorce JoHNSTONE STONEY, M. Aor, D.Sc., F.R.S., at the Evening Scientific See of the Royal Dublin Society, held March 22nd, 1899, : ee ae ae! iv Contends. PART II. PAGE XV.—The Carbonic Anhydride of the Atmosphere. By Prorsssor E. A. Lerts, D.Sc., Pu.D., and R. F. pee F.1.C., F.C.S. (Plates XVI. to XVIII), | eee ee iO, PART III. XVI.—Collembola from Franz-Josef Land (collected by Mr. W. 8. Bruce, 1896-97). By Grorcr H. Carrrnrrr, B.Sc. (Lond. ), Assistant Naturalist in the Science and Art Museum, Dublin, . é 271 XVII.—Pantopoda from the rene Sens aeadleee by Mr. W. 8. Fiano, 1897-98). By Grorcr H. Carpenter, B.Sc. (Lond. ‘. Assistant Naturalist in the Science and Art Museum, Dublin, 279 XVIII.—A Fractionating Rain-Gauge. By J. JOLY, D.Sc., F.R.S., Hon. Sec. , Royal Dublin Society, . 283 XIX.—On the Occurrence of Cyanogen Componnda | in Coal- Gas, ae of the Spectrum of Cyanogen in that of the Oxy-Coal-Gas Flame. By W.N. ae F.R.S., oven College of Science, Dublin, . : 289 XX.—Theory of the Order of romoten of Silicates in Yguestis Rocks. By J. Jouy, DSc), BRIS: Hon: Sec: “Royal Dublin Society, Professor of Geology and Miner Trinity College, Dublin, . C 298 XXI.—Recent Analysis of the Dublin Gas Supply, and Onsen thereon. By J. Emerson Ruynotps, M.D., D.S8c., F.R.S., Professor of Chemistry, Trinity College, Dublin, . - 9304 XXITI.—On certain Rocks styled ‘‘ Felstones,’’ occurring as Dykes in the County of Donegal. By GrenviLLE Te Coin, M.R.I.A., F.G.S., and J. A. Cunntnenam, A.R.C.Sc.1., B.A. (Plates XIX. and XX.), ¢ 314 XXIII.—On the Inner Mechanism of Sedinientaion “(prelinineee Note). By J. Jory, D.Sc., F.R.S., Hon. Sec., Royal Dublin Society, Professor of Geology and me Trinity College, Dublin, . 25 XXIV.—On the Nature and Speed of fine Ghensfecll @ianees ticch occur in Mixtures of Sewage and Sea-water. By Pror. K. A. Lerrs, D.Sc., Pu.D.; R. F. Buaxn, F.1.C., F.C.S.; W. Caupwett, BoA: ; and J. Haw THORNE, B.A., .- 6 3ee) XXV.—Studies in the Chemical Analysis of Fresh and Salt Waters. Part I.—Applications of the Aération Method of Analysis to the Study of River Waters. By W. E. Aprenny, D.Sc, A.R.C.Sce.1., F.1.C., Curator, and Examiner in Chemistry, in the Royal University of Treland, Dublinyea : 346 XXVI.—Notes on Temperature Observations made at Dunsink One vatory during the Eclipse of the Sun on es 28, 1900. By C. Martin. (Plate XXI.), . “ 362 XXVII.—Actinometric Observations of the Solar Blip. By Sis Rosert Beynert, Sch., T.C.D., 5 c 5 SOE XXVITI.—Influence of Pressure on the Seamtion of silicates in Igneous Rocks. By J. Jouy, M.A., D.Sc., F.R.S., Hon. Sec., Royal Dublin Society, Professor of Geology and] Maneraleey) in the University of Dublin, . A 378 Contents. IRD Ye XXIX.—A Contribution to the Theory of the Order of Crystallization of Minerals in Igneous Rocks. By J. A. CunnineHam, A.R:C.8c.1., B. A. (Plates XXII. and XXIII. pees 0 XXX.—On the Theory of the Stratified Discharge in Geissler Tubes. By H. Y. Gitt, 8.J., Clongowes Wood College, Co. Kildare, XXXI. —Prospecting for Gold in Co. Wicklow, and an Examination of Trish Rocks for Gold and Silver. By E. St. Joun Lysunn, A.R.C.8c.1., F.G.S., Mining Engineer, Pretoria. (Plates XXIV. and XXV. yo : 5 6 < a XXXII.—On some Problems connected with Atmospheric Carbonic Anhydride, and on a New and Accurate Method for Determining its Amount Suitable for Scientific Expeditions. By Proressor E. A. Lurts, D.Sc., Pu.D., and R. F. Brake, F.1.C., F.C.S8., Queen’s College, Belfast, : : XXXIII.—On a Simple and Accurate Method for Estimating the Dis- solved Oxygen in Fresh Water, Sea Water, Sewage Effluents, &e. By Prorsssor E. A. Lerrs, D.Sc., Pu.D., and R. F. Buaxkn, F.1.C., F.C.8., Queen’s College, Belfast, XXXIV.—The Application of the Kitson Light to Light-Houses and other places where an extremely Powerful Light i is required. By Joun R. Wicuam, M.R.I. PACA ate 4 c ° XXXV.—On the Pseudo-opacity of Anatase. By J. Jony, Sc.D., F.R.S., Hon. Secretary, Royal Dublin Society, C 0 XXXVI.—Incandescent Electric Furnaces. By J. Jory, M.A., Sc.D., F.R.S., Hon. Secretary, Royal Dublin Society, Professor of Geology and Mineralogy in the University of Dublin, XXXVII.—On an Improved Method of Identifying Crystals in Rock Sections by the use of Birefringence. By J. Jony, M.A., Sc.D., F.R.S., Hon. Sec., Royal Dublin Sonic Professor of Geology and Mineralogy i in the University of Dublin, XXXVIII.—A New Thermo-Chemical Notation. By James Hotms Pottox, B.Sc., ° 5 < s : S XXXIX.—On the Synthesis of Galactosides. By Prorressorn Hucu Ryan, M.A., D.Sc., F.R.U.I., and W. Sztoan Muitus, M.A. , University College, Dublin, . 0 : - XL.—On the Synthesis of Glucosides. By Prorrsson Hucu Ryan, M.A., D.Sc., F.R.U.I., University College, Dublin, XLI.—On the Preparation of Amidoketones. By Prorrsson Hueu Ryan, M.A., D.Sc., F.R.U.I., Catholic Gane School of Medicine, Dublin, XLII.—A Theory of the Molecular Constitution of Suporatrated Solutions. By W. N. Harttey, F.R.S., 0 . XLIII.—Award of the Boyle Medal to Professor Thomas Eretous Wiye\os IDaSiGk, INGIRSon IEE : . PAGE 383 415 422 436 454 482 485 495 529 543 vi Contents. PART V. XLIV.—On Haze, Dry Fog, and Hail. By W. N. Hanttey, D.Sc. Se., F.R.S., Royal College of Science, Dublin, C < aeoete XLV.—The Nebula areata Nova Persei. By W. E. ere ie A XLVI.—Method of Observing fle Altitude of a Celestial Object of Sea at Night-Time, or when the Horizon is obscured. By Vio Jory, Sc.D., F.G.8., F.R.S., &c., Hon. Ser Boye Dublin Society, ! : XLVII.—On the Progressive Dy aamouletaroupuiem of a Porkgnie Andesite from County Wicklow. By Henry J. we B.A., F.G.S. (Plates XXVI. and XXVII.), . XLVITI.—Some Results of Glacial Drainage round Montpelier Hill, County Dublin. By W. B. NE B.A. (Plates XXVIII. and XXIX.), . : 6 XLIX.—On the Occurrence of Cassiterite in the Tertiary Granite ‘of ite Mourne Mountains, County Down. By Henry J. Seymour, B.A., F.G.S., 3 . 3 5 C INDEX, on a Or DATES OF THE PUBLICATION OF THE SEVERAL PARTS OF THIS VOLUME. Part 1.—Containing pages 1to 106. (October, 1899.) Mr cone 43 s» 107 to 270. (March, 1900.) songs = » 271 to 882. (November, 1900.) es ‘ », 983 to 546. (Sept., 1901.) Pees) on » 947 to 584. (February, 19038.) ERRATUM. Page 575, line 6 from top, for Published September 20, ead Published October 24. Pe ee uke Piet, Merete a , THE OF THE ROYAL DUBLIN SOCIETY. CONTENTS. 1.—Ooralloriiza innata R. Br., and its Mycorhiza. By A. VaucHan JeNNINGS, F¥.L.8., F.G.S., and Hewry Hanna, M.A., B.Sc. (Plates I. ‘and IL. ‘ : I. —Mining and Minerals in the Transvaal and Swazieland. By EE. Sr. Jonn Lysurn, M.H., A.R.C.Sc.1,, F.G.S. (Plate II1.), oan —A List of Irish Corallinaces, By T. JOuNSON, D.Sc. (Lond.), F.L.S., Professor of Botany, Royal College of Seience, and Keeper of the Botanical Collections, Science and Art Museum, Dublin; and Miss kh. Hensman, .—Notes on a Method of comparing the relative Opacities of Organic Substances to the X Rays. By Ernest A. W. Henry, B. A., —The Kieselguhr of Co. Antrim. By Jamus Hotms Potxox, B. Sc., be Vi. —0On the Correction of Errors in the Distribution of Time Signals. By Sir Howard Gruss, F.R.S., Vice-President, Royal al a Dublin Society. (Plates LV. and V. Jee : .—Proposal for the Utilization of the ‘‘ Marconi” System of Wir e- less Telegraphy for the Control of Public and other Clocks. By Str Howarp Gruss, F.R.S., Vice-President, R.D.S., —On a Hydro - Dynamical Hypothesis as to Electro - Mag netic | Actions. By Pror. Grorce Francis Fitz Gera, F. “R. 8., _ TX.—Note on the Results that may be expected from the ’ proposed Monster Telescope of the Paris Exhibition of 1900. By Str -Howarp Gruss, F.R.S., Vice-President, R.D.S. (Abstract), —On the Concentration of Soap Solution on the Surface of the Liquid. By Davin Henry Hart, B.A., ‘The Rio Del Fuerte of Western Mexico, and its Tributaries. By Kinsiny Drypen Doytx, M.A., Assoc. M. Inst. C.E. oe Oy VES to XV.); é te on Improvements in the Means of causing Oceultations or _ Flashes in Buoy Lamps and Beacons in which the Lights Burn Continuously for a Month or a longer time. By JOHN 3 R. Wiewam, M.R.I.A., —Survey of that Part of the Range of Nature’s Operations which __ Man is competent to study. By G. Jonnsronr Sronry, M.A., D.Sc., F.R.S. (Figures 1 to 6—6 as Plate), —Award of the Boyle Medal to Guorcr JonnstonE STONEY, M. An D.Sc., F.R.S., at the Evening Scientific Meeting of the Royal Dublin Society, held March 22nd, 1899, ; A i WILLIAMS AND NORGATE, oe HENRIETTA-STREET, COVENT GARDEN, LONDON; 20, SOUTH FREDERICK-STREET, EDINBURGH; anv 7, BROAD- STREET, OXFORD. 1899. vy Price Four Shillings and Sixpence. - (N.S) OCTOBER, 1899. Part 1. PAGE | Roval Dublin Society, FOUNDED, A.D. 1731. INCORPORATED, 1749. aS ~ a EVENING SCIENTIFIC MEETINGS. Tue Evening Scientific Meetings of the Society and of the associated bodies (the Royal Geological Society of Ireland and the Dublin Scientifie Club) are held on Wednesday Evenings, at 8 o’Clock, during the Session. : Authors desiring to read Papers before any of the Sections of the Society are requested to forward their Communications to the Registrar of the Royal Dublin Society at deast ten days prior to each Evening Meeting, as no Paper can be set down for reading until examined and approved by the Science Committee. The copyright of Papers read becomes the property of the Society, and such as are considered suitable for the purpose will be printed with the least possible delay. Authors are requested to hand in their MS. and necessary Illustrations in a complete form, and ready for transmission to the Editor. THE SCIENTIFIC PROCEEDINGS OF THE ROYAL DUBLIN SOCIETY. I. CORALLORHIZA INNATA R.Br., AND ITS MYCORHIZA. By A. VAUGHAN JENNINGS, F.L.S., F.G.S., ann HENRY HANNA, M.A., B.Sc. (Puavzs I. anp IT.) [Read Junz 22; Received for Publication June 28; Published Octoner 22, 1898.] HE orchid genus Corallorhiza has long been of interest to botanists on account of the peculiar rhizome from which it derives its name, the absence of roots, and the want of chlorophyll usually associated with a saprophytic habit which it shares with such forms as Epipogon and Neottia.' Any additional information bearing on the nutrition of such a specialised type as Coralloriza must be of interest, as we have reason to believe that in this case the relationship which obtains between the mycorhiza and the host plant is of a very complex nature, and not at present thoroughly understood. Of late years new light has been thrown on the question of the nutrition of saprophytes and certain other plants, owing to the frequency with which fungoid elements are found in association with their roots or rhizomes. Thus, if we take up a young beech plant and carefully wash the roots with water, we observe numerous fine root fibres to which there cling small portions of humus; no root hairs are ‘ Chlorophyll is not entirely absent. The flowers and upper part of the scape are of a faint yellow-green colour, but the leaves are reduced to colourless sheathing scales. SCIEN. PROC. R.D.S., VOL. IX., PART I. B 2 Scientific Proceedings, Royal Dublin Society. present, but instead we find that the entire surface of the fibres is covered over with a web of fungal hyphe. We are here dealing with a “ mycorhiza”’; that is, the association of root fibres and fungal hyphe living in intimate physiological connexion with them. orcas Rhizome, with young aerial shoot (a) nat. size, showing numerous tufts of hairs (0). There may be advantages accruing both to the fungus and to the beech plant from such a union; the former may help the green flowering plant to obtain water and salts from the soil, while in return it may receive from its host some of the organic compounds manufactured in the green leaves. So essential to the well-being of the host plant is the presence of the mycorhiza, that if the development of the latter is prevented, the normal development of the beech plant does not take place ; and the relationship may perhaps be regarded as a true symbiosis. JENNINGS & Hanna—Corallorhiza innata R. Br. 3 Frank,' who has conducted many experiments in this direction, also concludes, from growing spruce fir seedlings in sterilized and unsterilized soil that the mycorhiza is of service to the plant in enabling it to make use of the nitrogen compounds present in the humus. Althongh it is possible that there are advantages accruing to a mycorhiza from such a symbiotic union with the roots or rhizomes of a green flowering plant, one does not see so clearly what benefits Fig. 2. Portion of the mycelium of the mycorhiza, showing the ‘‘ clamp-connexions.”’ accompany the union of a fungus mycelium with similar organs of a plant devoid of chlorophyll. Thomas’, in his observations on Corallorhiza in America, is of opinion that the fungus supplies food to the host from the decaying vegetable matter of the surrounding soil. ; The genus Corallorhiza, containing some twelve well-defined species, is of wide distribution, extending throughout the northern hemispheres of the Old and New Worlds, and in the latter ranging as far south as Mexico. In the British Islands this genus is represented by one species, C. innata R. Br. . According to Babington and Hooker it is found only in Hast Scotland, from Ross to Berwick, living in boggy woods, but it is 1 Ber. d. Deutsch. Bot. Gesell. Bd. x., p. 577. 2 Botanical Gazette, vol. xviii. B2 4 Scientific Proceedings, Royal Dublin Society. very rare. In the high pine woods of Central Hurope it is local but not uncommon, and the present observations were made on specimens from the Eastern Alps. The coralloid rhizome differs markedly from the usual type of underground stem met with in Monocotyledons, except that of Epipogon, which is on the whole © similar. It grows embedded in a soil unusually rich in humus compounds. Chlorophyll is often stated to be entirely absent, or present only in the ovary (Warming); but, as above noted, it may be slightly developed in the flowers and top of the scape. The EorGeenos Transverse section through the outer layers of the rhizome. aerial portion of the plant is a simple scape, bearing only colourless leaf-sheaths, and at the top a raceme of small pale flowers. The fungal hyphe constituting the mycorhiza (when examined microscopically) are seen to have the following characters (fig. 2). They are distinctly septate and repeatedly branched, of a yellow, white, or brownish colour. They possess numerous “ clamp- connexions,”’ indicating that the mycelium belongs to one of the higher fungi, a conclusion which is supported by the fact, that young agaricoid sporophores have been, in one instance, found growing from the mycelium round the rhizome. ‘These refused to develop further on cultivation, but comparison with the early stages of Clitocybe infundibuliformis Sch., found a few feet distant, indicates that this is the species to which they, in that case, belonged (Plate 1.). Attempts to determine whether the mycelium could be referred to any one species of fungus have been made in the pine woods of Davos Platz by one of us,’ who has had plants under observation 1 A. Vaughan Jennings. JENNINGS & Hanna— Corallorhiza innata R. Br. 5 during three summers, and these experiments tend to show that so far as this district is concerned the mycorhiza of Corallorhiza is a hymeno- mycete and commonly an agaric. In addition to the agaric referred to above, there are others which have been found in very close proximity to the Corallorhiza; for instance, species of Tricholoma (T. ionides, Bull?), My- cena (IM. umbellifera, Sch. ?), and Corti- narius (C. subferrugineus, Batsch.). It is also interesting to note that one of the subterranean hymenomycetes, evi- dently the Hysterangium stoloniferum of Tulasne, has been found in several instances among the rhizomes. None of the cases observed showed any special hyphal characteristics to absolutely iden- tify them with the mycorhiza, but their mode of occurrence leaves little doubt as to the existence of a real connexion between the mycelium of these fungi and the symbiote or victim of the Coral- lorhiza. The rhizome when carefully removed from the soil and gently washed, shows, scattered over the surface of the grow- ing shoots, numerous papille, from which tufts of hairs arise (fig.-1, 0). These hairs are, on an average, ‘810 mm. to 432 mm. in length, and :054 to 027 mm. in breadth: some have rounded apices, others appear abruptly truncated ; and intermediate stages exist which are of great interest. At the tips of the hairs changes evidently of a chemical nature can be seen in progress; the apices lose Fic. 4. Three cells from the outer layers of the cortex, showing hyphe piercing the cell-walls. their definite outline, the walls break down and appear mucila- ginous and granular as if ferment-action was going on. The walls of 6 _Scientifie Proceedings, Royal Dublin Society. some seem to become weakened along a spiral line (as in Plate 11.) apparently corresponding to the course of intrusive hyphe. The hyphe outside the rhizome can be traced inside the hairs; Fic. 5. Cells from the mediocortex, showing hyphe in various stages of absorption, and starch grains making their appearance. passing down, singly and spirally, or in bundles, to the cortical tissues of the rhizome (Plate m1.).? 1It seems evident, therefore, that these hairs are specialised structures for the attraction and capture of the mycorhiza, and if a special name is needed they might be termed ‘‘ mykokleptic”’ hairs. Jennines & Hanna—Corallorhiza innata R. Br. a The hyphee in the soil outside the plant and those inside the hairs and cortical tissues are similar and continuous, and have the structure shown in fig. 2. Thomas' observed the presence of the papilla over the surface of the rhizome and also the presence of hairs. He failed, how- ever, to demonstrate the connexion between the hairs and the mycelium in the surrounding soil, considering that the probable function of the former was the purely mechanical one of anchoring the plant to any substance with which it might happen to come into contact, a purpose for which they are evidently inadequate. The axis of the aerial shoot which arises from the rhizome grows by means of a stratified apical growing point, on the sides of which scale leaves arise in acropetal succession, covering up the growing point (fig. 1). Figs. 6 and 7. Cells from the mediocortex, showing hyphe in various stages of absorption, and starch grains making their appearance. Taking sections through the rhizome the following structure is noted :— 1. Outer layers.—There is a definite superficial layer of cells, elongated longitudinally ; and at irregular intervals, where sections of papillz are to be seen, the hairs arise as outgrowths at right angles to the surface (Plate m.). On the outer wall of the super- ficial layer of cells there is a thin cuticle; below it two or three layers of thin parenchymatous, isodiametric cells with small inter- cellular spaces occur (fig. 8). These cells have large nuclei and protoplasmic contents and small starch grains; the nuclei are 1 Loe. cit. sup. 8 Scientific Proceedings, Royal Dublin Society. surrounded by the starch grains, some of which also lie scattered through the protoplasm. Numerous fungal hyphe are observed passing more or less directly through these outer layers.. This is an important fact, and is especially obvious in transverse sections of the rhizome in the neighbourhood of a papilla. 2. Internal to the cells constituting these outer tissues there occur one or more layers of cells, usually three, which have thin cellulose walls, and contents markedly different from those of the outer layers ; each cell is filled with a coiled mycelium ; the cell sap is scanty, and the hyphz may be observed piercing the cell walls. Fic. 8. Surface of a nearly median section through lobes of the rhizome, showing the dis- tribution of the mycorhiza in the tissues, as indicated by the light bands, (x 25.) Where the hyphe pass straight through from one cell to another, there is a paucity or a marked absence of starch grains (fig. 4). 3. More internally we come to cells which have a very different appearance ; these cells are large, thin-walled, and provided with abundant protoplasm; starch grains are numerous. ‘The latter seem to increase in the cells in proportion as the hyphe disappear (fig. 5, a). The hyphe in no instance were observed to swell into bladder-like bodies in the neighbourhood of the nuclei, the filaments being practically of the same width in all parts of the coil. The mycelium may be observed in all stages of degeneration in the Jennines & Hanna—Oorallorhiza innata R. Br. 9 cells of this region. Minute bodies in groups make their appearance along the course of these degenerating hyphe; the nucleus is in a state of great activity, becoming larger, and containing a number of bodies which stain deeply with Hoff- mann’s blue. This is an indication of the increase of materials in the substance of the nucleus, a fact of some significance when we recall the fate of the hyphe in the cells; their walls collapse and become shrunken, and finally the contents of the cells become one homogeneous mass. Following Groom’s' termi- nology we may name the region the mediocortex as characterised by the presence of these degenerating fungal masses. Inside this mediocortex there are usually two layers of parenchymatous cells with walls of cellulose, containing abundant starch but no hyphee. In the centre of the rhizome there is a simple vascular cylinder of somewhat modified collateral bundles, composed of small and usually quite rudimentary elements, the phloem in each case being confined to the periphery. The hyphae, after passing into the hairs, are distributed in the deeper tissues in a definite and regular manner. They do not appear to pass from the underground portions of the plant into the young aerial shoots. Above the line marked a in fig. 1 no hyphe were present in any of the cells, nor were they present anywhere in the cells of the flower stalk. If we take a longitudinal section through a small portion of the rhizome, such as that seen on the right hand in fig. 1, a little to one side of the median plane, a very peculiar appearance is seen of alternating bands of light and shade on the surface of the section. On closer examination the light coloured bands are found to be due to the presence of the endotrophie hyphe forming dense coils in the cells. SUMMARY AND CoNCLUSIONS. From a consideration of the facts observed there can be very little doubt that ultimately the hyphe present in the cells are absorbed and made use of in forming food materials for the host plant. 1 Ann. Bot. 1895. 10 Scientific Proceedings, Royal Dublin Society. The tufts of hairs on the numerous papille covering the rhizome appear to act as traps for the mycorhizal hyphe, the latter being attracted by the presence of some chemotaxic substance formed as a result of the changes going on in the walls of the hairs especially at their tips, which seem to make suitable growing places for fungoid hyphe. The hyphe pass down the hairs and through the outer layers of the rhizome without forming coils in the cells; enter the deeper lying cells and form coils there, and then pass on to the mediocortex where they are ultimately absorbed and converted into food materials for the host plant. This tends to strengthen Frank’s view that the fungus is a living organism captured for the benefit of the host plant. An important point bearing on his comparison of such a “host”? to a carnivorous plant is the behaviour of the hyphe towards the nuclei of the cells. Inno case could we make out an enlargement of the hyphe in the neighbourhood of the nucleus in cells outside the medio- cortex; the nucleus was not perceptibly larger in the cells con- taining coils of mycelium than in those towards the epidermal layers in which such coils were absent. No bladder-like swellings were observed similar to those described by Groom,! in Thismia Aseroc (Ber.),a saprophytic monocotyledon belonging to the order Burmanniaceze. In some cells of the mediocortex a peculiar semblance to swollen ends of hyphee has been observed near the nucleus, but this appearance was found to be brought about by the shrunken protoplasm becoming cup-shaped, with one rim very much thickened. Starch is most abundant in cells in which the hyphe are in a state of decomposition. In the mediocortex little granules in groups occur along the strands of hyphee, and increase in proportion as the absorption of the hyphee in the cells proceeds. This makes it doubtful if the hyphe obtain any food matter from the host after they have once been attracted into the tissues (fig. 5, 0). The peculiar characters of the hairs in this instance, and the histological features of the infected cells point to the host 1 Ann. Bot. 18965. Jennines & Hanna—Corallorhiza innata R. Br. IL plant as being at least by far the larger shareholder in the sym- biotic relationship, if it can be regarded as such. More probable seems the view that there is no symbiosis, but that the fungus is captured and utilised by the orchid without any compensating benefit to itself. EXPLANATION OF PLATES I. anp II. Piatt I.—Fig. 1.—A plant of Corallorhiza innata, R. Br. (natural size) showing (a) aerial shoot with terminal raceme of flowers; (4) coralloid rhizome; (c) fungus mycelium ; (d@) young sporophores of Clitocybe infundibuliformis. Figs. 2 and 4.—Aeriah branch of the rhizome; surface view and section, showing the buds sheathed in brown scales, the scars of older, fallen scales, and the tufts of fungus catching (“mykokleptic’’) hairs. Figs. 3 and 5.—Similar views of the termination of subterranean lobes of the rhizome. Puate II.—Transverse section through portion of the rhizome, showing a group- of the hairs which collect and transmit the hyphe of the mycorhiza. [ 12 ] II. MINING AND MINERALS IN THE TRANSVAAL AND SWAZIELAND. By E. Sr. JOHN LYBURN, M.E., A.R.C.Sc.1., F.G.S. (Puare IIL) [Read Junr 22; Received for Publication Ocronsr 7; Published NovemBer 380, 1898.] Introduction.—The object of this communication is to afford some information on the reality and extent of the mineral wealth of the Transvaal and Swazieland, from data acquired in the course of the last two years, during which I held the position of consult- ing Mining Engineer to Mr. E. F. Bourke, a gentleman largely interested in the mining industry. Exceptional opportunities have thus been afforded me of studying the geology and mineralogy of these countries. Prior to my engagement with Mr. Bourke I held the position of assayer and surveyor to several gold mining companies on the Witwatersrandt. Geology.—The elevation of the Witwatersrandt (White water- shed) varies from 5500 to 6000 feet above sea-level). The Wit- watersrandt forms the water-shed of the principal rivers of the Transvaal, which is drained by the Orange River and its tributaries to the South Atlantic Ocean on the south-west, and the Limpopo, or Crocodile River and its tributaries into the Indian Ocean, on the south-east. To illustrate better the relations of the strata in the Witwaters- randt I have prepared a diagrammatic section (Plate 11.). On the working out of this strata I was engaged during many months of actual survey in the field; it shows three distinct systems. Ist. The primary, represented by the granitic rocks north of Rietfontein, north of Johannesburg. 2nd. ‘The Cape System, containing the famous Randt deposits, divisible into five series :— I.—Hospital Hill series, consisting of quartzites sand-stones, and ferruginous shales, the latter banded, and con- taining magnetite and titanite. They are regarded Lysurn—WMining and Minerals in the Transvaal, ete. 13 by the prospector as the guides to the location of the Main-reef series, prospectors maintaining that the Main-reef lies at a distance varying from 12 to 14 miles south of these shales. Many similar beds are to be met with west of Johannesburg. II.—The Banket (= puddingstone in Dutch) series, embracing the sandstones, quartzites, and conglomerate beds of the Witwatersrandt, may be sub-divided into—1, the. Main-reef series; 2, the Bird-reef series; 3, the Kimberley series; 4, the Elsburg series. IIt.—The Black-reef series. IV.—The Dolomitic Limestone. V.—The Magaliesburg series. 1. Main-reef series.—The main-reef series mostly strike east and west, with southerly dip, and can be traced for about twenty- eight miles. At Boksburg, east of Johannesburg, the beds dis- appear under the coal, or Karoo formation, and reappear in the vicinity of Benoni, and can be followed for a distance of about six miles, disappearing again under the Coal-measures. Following the outcrop of the series where observable, the general formation is found to strike in the extreme east of the district north and south, with westerly dip. The series are seen at Heidelburg striking east and west, with northerly dip, thus completing a syncline. To the west of Johannesburg in the Krugersdorp district, the series are much faulted and other conglomerate beds are met with. The Main series consist of three productive reefs, namely, the Main- reef, the Main-reef leader, and the south reef, and are separated by sandstones of variable thickness, the distance from the Main- reef to the Main-reef leader varying from a few inches to 7 feet, and from the latter to the South reef from 30 feet to 110 feet. Other reefs are known to exist, but are of no commercial value at present. The thickness of the Main-reef ranges from 3 feet to 12 feet. The Main-reef leader from 1 inch to 3 feet, and the South reef from a single pebble to 5 feet 6 inches. The South reef is the richest ; the Main-reef the poorest. The conglomerates are composed of white and smoky pebbles presenting a waterworn appearance and are cemented by silica, \ 14 Scientific Proceedings, Royal Dublin Society. impregnated with iron pyrites, the gold being obtained from the cementing matter. The pebbles vary greatly in size, ranging from the size of a small marble to that of a turkey’s egg. 2. Bird-reef series.—These consist of eight beds of conglomerate. In some places gold is found in paying quantity, but the series “has not yet been fully prospected. 3. Kimberley series.—These consist of a large van hea of conglomerate beds varying in thickness. South of Florida, the Kimberley-reef proper is about 100 feet thick, gold in paying quantities not having hitherto been discovered in it. 4, Elsburg series.—These consist of a large number of beds of considerable thickness, and here, too, gold in paying quantities has not been met with. Each and all of these series are accompanied by their own particular characteristic pebbles, by which they are easily recog- nized. Overlying the Elsburg series, an extensive sheet of amygda- loidal diabase is found, forming the Klipriviersburg, the Black reef resting on this formation, with the dolomitic limestone superimposed. In succession appears the Magaliesburg quartz- ite sandstone. North of the Main-reef series, in the vicinity of Rietfontein, a thin bed of conglomerate is encountered, called Du Preez reef, on which successful work is being carried on. The Black reef series.—This consists of quartzites which lie unconformably on the Banket series, the angle of dip ranging from 5° to 15° from the horizon. ‘Faken as a whole, this reef is remark- ably “‘ patchy,’ and varies in thickness from that of a single pebble to 5 feet. In some places the reef is absent. The pebbles are cemented with the sulphides and oxides of iron. The Dolomitic Limestone. —This overlies unconformably the Black reef. In appearance it is bluish grey, and contains a large percen- tage of magnesia. Numerous siliceous beds occur, running through it, conformably with the stratification. Quartz veins destitute of gold are also found, cutting through the strata. Underground cavities also form a characteristic of the group. The thickness of this dolomitic limestone may be set down at about 10,000 feet. The Magathesburg series.—This consists of quartzites, sandstones, and shales, which form the hills known as the Magaliesburg range. Lysurn—Wining and Minerals in the Transvaal, ete. a3) Numerous sheets of igneous rock are interbedded with the quartz- ites. The series is devoid of fossils. To the north of Pretoria the shales contain galena. The Karoo System.—This system comprises the sandstones, shales, and Coal-measures. The sandstones are arkose in character. Red sandstone predominates at the surface, and is characteristic of the coal-bearing deposit. It is hard and compact where exposed. Shales are found underlying the sandstones. The formation may be divided into the Upper and Lower Karoo. Ishall only refer to the Molteno beds, which are coal-bearing. The distribution of these beds has hitherto been imperfectly worked out; they are met with in the Cape Colony, extending into the Middleburg district of the Transvaal, and are traceable into Orange Free State, Natal, Zululand, Pondoland, and the Portuguese territory ; they mostly lie in a horizontal position; their age is an open question. The fossils so far obtained are Sigil/aria and G'lossopteris (the latter is also met with in the Indian Trias). From my own observation, I estimate the coal area of South Africa to be about 175,000 square miles, or, say, about 400 miles by 440. Recently a coal seam of the abnormal thickness of 211 feet has been discovered to the east of Johannesburg, on the farm Zuur- bekom. I consider this to be one of the greatest coal discoveries of recent times. The sandstones and shales overlying the coal, totaling 320 feet. As to the quality of South African coal, it may be stated that its average calorific value is about 1 lb. for 7 lbs. of steam compared with Welsh coal, 1 lb. of which gives 11 or 12lbs. of steam. Mining.—The underground development is performed by means of rock-drills driven by compressed air, white miners ope- rating the machines. ‘Stopping,’ or breaking down the ore, is done by hand, and the work alloted to Kafirs, supervised by white miners, who charge and fire the blasts. Machine stopping is replacing the hand method. The deposits of the Witwatersrandt are at present worked by rectangular shafts, both vertical and inclined. In the early days of the industry, vertical shafts were much preferred, cross-cuts being driven to intersect the reef. At the present time the out- crop properties are being worked by inclined shafts, or, in other words, shafts sunk on the reef. Inclined shafts are preferred 16 Scientific Proceedings, Royal Dublin Society. on account of the sinking being made in the reef proper, thus always being in touch with the reef, giving all necessary data as to value per ton thickness of reef. The ore won in sinking on the incline is afterwards profitably treated by the “reduction plant,’ whereas in the vertical system, the rock taken out consists only of the country quartzite, which is valueless. The cost in either case is practically about the same. It is now the rule to sink the inclined shaft in the Main-reef leader or middle reef, 7.e. in the body of the series. Deep-level Shafts.—It may be advisable to define the term “‘ deep-level.”’” The reefs dip in a southerly direction. The out- crop, as the word implies, is that part of the ore-body which is exposed at the surface, the ore-body being inclined and dipping to the south; the further south claims are held, the greater vertical sinking is needed to strike the reef. Data regarding the depth at which the reef should be struck depend upon the dip of the reef and the extent of the claims held by the outcrop Company south of the outcrop. A claim consists of 60,000 square (Cape) feet,’ equal to 400 (Cape) feet measured along the outcrop, by 150 (Cape) feet at right angles to the same. The diagram on Plate 11. shows four claims on the dip, equal to 600 (Cape) feet measured at right angles to the outcrop. ‘The deep-level shaft would be sunk on claim No. 5. The vertical shaft is used to reach the reef in depth. When the reef is intersected, the shaft is continued on the inclina- tion of the reef. It is a very open question whether the shaft should be continued on the vertical, or follow the dip of the reef. In sinking on the reef as mentioned in the cases of outcrop properties, all data are obtained as to the value and thickness of the reef, which could not be furnished by a vertical shaft in barren ground. On the other hand, the wear and tear on the vertical system is much less than that on the inclined. The turning point (that is to say, the point where the vertical branches into the in- cline) is a source of trouble and loss of time, as it becomes necessary to slow down the hauling engines, on arrival at the point mentioned. The dip of the deep levels varies from 20° to 30° from the horizontal. 11083 English feet equal 1000 Cape feet. Lysurn—WMining and Minerals in the Transvaal, ete. 17 The question of maximum workable depth arises in connexion with the deep levels of the Randt. In connexion with this ques- tion it may be learned from the State Reports that experiments have been made on the property of the Robinson Deep-Level Gold _ Mining Company. The observations were made in a shaft 2067 feet deep, which was not connected with any other shaft on the estate. The result gave a rise of 1°C. in temperature for every 492 feet, say (1° C. for 150 metres), the ordinary rate of increase being in EKurope and America 1° C, for 30 to 31 metres. Experiments were also carried out on the Langlaagte Company’s property, the depth of the shaft being 1083 feet, resulting in demonstrating a rise of 1° C. for each 300 feet (or 1°C. for 92). Taking 5000 feet as a limit to which working can actually be pushed, and considering it, in view of the less favourable of the above-mentioned experiments, viz. that of the Langlaagte Deep, it would appear that the total increase of temperature to be ex- pected would not exceed 17° C. at 5000 feet, which, added to the temperature at the top of the shaft, in this case 20° C., would bring the temperature, which the worker would be exposed to, up to a7 C., equivalent to 98° F., a temperature which would in no practical way impede mining operations. The fact is to be borne in mind that these tests were carried out in shafts, entirely dis- connected from any other. The result of connecting shafts would undoubtedly be a lower- ing of temperature in both. Judging by the above data it will be reasonable to infer that mining operations can be carried on, in these countries, to a very great depth. As bearing on the geology of the country and the working of the reefs, attention should be called to the faults occur- ring in the Randt which are either of the ordinary class or of the class of fault known as the “ overthrust fault,” and called in Hurope “ reversed fault.” ‘lhe existence of these faults will largely influence enterprise in the future, in deep levels (Plate 11.). On the property of the Witwatersrandt Gold Mining Company, two outcrops of the Main-reef series are known to exist. ‘The reef series has been thrown up by an overthrust fault, the fault-plane being filled up by dyke matter, viz. dolerite. This at first gave rise to considerable speculation, many mining men believing it to C SCIEN. PROC. K.D.S., VOL. IX., PART I. 18 Scientific Proceedings, Royal Dublin Society. consist of two independent reef series ; however, shaft-sinking has proved it to be a case of overthrust faulting. Similar faulting may also be encountered at the Robinson and the Langlaagte Royal, establishing the same deduction. I could multiply instances, all pointing to the same conclusion. Treatment of the Ore-—The ore having been brought to the surface in the “ skip”’ is sent to the sorting machinery. Circular sorting tables are mostly in use. Kafirs stand around these tables and reject all country rock, quartzite, &c. The reef matter is thrown into the crushing machinery, which reduces the ore to fragments representing about 2-inch cubes. This product is carried forward in trucks driven by wire- haulage to the “ stamp-battery,” where it undergoes crushing to about “ four hundred mesh,” the standard of fineness of the mesh differing in many mines. The crushed material passes over copper plates amalgamated with mercury, which seizes the free gold. The residue (or ‘“tailings”), which contains about 33 per cent. of the total gold, is then subjected to the cyanide treatment, by being pumped (or elevated by a wheel) into the Spitzlutzen or hydraulic classifiers, which separate the coarser sands and pyrites from the finer sands, or slimes, the latter flowing away into the slimes-dam, to undergo further operation, whilst the coarser sands are dealt with in the cyanide tanks, which consist of wooden structure, as in the older establishments, but which are being discarded by the more modern undertakings in favour of iron tanks. Tn these tanks the material is treated with cyanide of potassium solution for a few days, after which it is drawn off and passes through wooden boxes charged with zinc shavings, resulting in the precipitation of the gold in the form of fine black slime, which, having been dried and calcined, is smelted in graphite crucibles, yielding “cyanide gold,” containing an average of 750 “ fine,” in which form it is exported to the English refiners. In many mines electrical precipitation by the aid of lead plates is rapidly becoming availed of, which effects a saving of the cyanide. The gold is deposited on lead plates, which are after- wards subjected to cupellation. The Occurrence of Gold in the Transvaal and Swasieland.—In the first portion of this communication I dealt with the occurrence of Lyspurn—Mining and Minerals in the Transvaal, ete. 19 gold in the beds of the Witwatersrandt; I now propose to give a succinct account of other localities in which gold has been proved to exist. Gold was first discovered in 1869, in the North-Eastern Transvaal, in a district embracing the Zoutpansburg, Houtbosch- burg, Murchison, and Letaba goldfields. The gold occurs in quartz reefs, which are mostly of the bedded-vein type, true fissure veins being rarely encountered. The reefs are interstra- tified with schistose rocks. Mining at present is at a standstill in this district. Auriferous stibnite has been discovered in the Murchison district. Gold in the De Kaap or Lydenburg Districts —The Lydenburg district consists of an extensive plateau, dipping about eight degrees to the west; the strata lie partly unconformably on the Swazieland schists, and partly on the rocks forming the low country. It may be divided into four systems :— 1. The underlying schists. 2. The Drakensburg sandstones and quartzite. 3. The dolomitic limestones. 4. ‘The upper schists and sandstones. The gold-bearing beds are found in the Drakensburg system, in the dolomite beds, and in the upper schists and sandstones. The conglomerate bed of the Kaapsche Hoop, or Devils’ kantoor, contains gold, but up to the present in unremunerative quantity. This conglomerate is highly mineralized with iron pyrites, the pebbles ranging from a smoky quartz to white. The cement is coarser than that of the Witwatersrandt. The Dolomite beds.—The auriferous reefs found in these beds consist of quartz and pyrites, with occasional bands of chert, con- taining manganese. ‘The gold occurs in the cavities left vacant by the chemical decomposition of the iron pyrites. Diorite sheets always accompany the reef, and range from the “ hanging-wall”’ to the “ foot-wall.” On the property of the Barrett Gold Mining Company, sheets of a highly felspathic igneous rock occur. They are much de- composed, and intersected by quartz veins, which however seldom sarry gold, which only occurs in the igneous sheets. C2 20 Scientific Proceedings, Royal Dublin Society. Gold in the Barberton District.—The Swazieland schists mostly predominate here, quartz-bedded veins generally carrying the gold. In the Steynsdorp district, gold has been discovered in a lode, associated with copper pyrites and carbonate of iron. On the Piggspeak, in Swazieland, the white sandstones and quartzite eontain gold. Swazieland.—This country lies to the east of the Transvaal. It is practically unexplored. Gold, tin, and other metals un- doubtedly exist there, but capital is not forthcoming to carry out the necessary exploration. On the Occurrence of other Metals.—At present there are no mines in operation for the production of the following metals, although they exist, viz.:—iron, lead, copper, tin, antimony, silver, and mercury. Tron.—Large deposits of magnetite and hematite are found in the Pretoria and Middleburg districts, but remain unproduc- tive. Lead.—Galena is found in the Machadadorp district, in the Pre- toria and Delagoa Bay railway country ; it contains a large per- centage of silver, the ore body consisting of quartz impregnated with galena. Galena also occurs in the Pretoria and Malmani districts. Copper.—Copper is now being prospected for in the Bronk- horstspruit district, and several leads of chalco-pyrite have been discovered. Tin.— Alluvial cassiterite occurs in the Embabaam, Swazieland. The mother lode has not yet been discovered. Antimony.—Antimony ore, occurring as stibnite, is found on the Murchison, north-east Transvaal. Silver.—Silver is found, combined with bornite copper ore, in the Pretoria district, in addition to that already mentioned. Mercury.—This metal has been discovered on the Portuguese border. Diamonds.—The recent discovery of diamonds in the Transvaal has induced me to give a short description of the diamond deposits of South Africa. The existence of a pipe or chimney is character- istic of all the diamond deposits of South Africa. The yellow ground in which they were first found passes, at a deeper level, into what is termed hard blue, or “kimberlite.” At first the Lysurn—WMining and Minerals in the Transvaal, etc. 21 appearance of the blue ground caused much excitement, the general opinion being that the yellow ground had become ex- hausted ; the yellow ground is, however, neither more nor less than decomposed blue ground. The diamond-pipes contain a large quantity of foreign mate- rial, in the shape of shale, sandstones, dolerite, and granite. The sandstones and shales, have evidently fallen in from the sides, the granite having been carried up in the ascent of the molten material. The diamond matrix (kimberlite) consists of garnets (pyrope), ilmenite, mica (vaalite), and olivine crystals, constituting a serpen- tine breccia. The rock in a state of decomposition has a greasy feel. In the river diggings, crystals of ilmenite, pyrope, and olivine, accompanied by agates and zeolites, are found. Recently, in the neighbourhood of Pretoria, a pipe containing kimberlite (?) has been discovered. Alluvial diamonds are also being found in the south-western border of the Transvaal, in the vicinity of Christiana. I may here add that diamonds occur in the strata of all the diffe- rent geological periods of South Africa. [ 22 ] III. A LIST OF IRISH CORALLINACEA. By T. JOHNSON, D.S8c., (Lond.), F.L.8., Professor of Botany, Royal College of Science, and Keeper of the Botanical Collections, Science and Art Museum, Dublin; and MISS R. HENSMAN. [Read Aprit 20; Received for Publication! NovemBer 26 ; Published January 4, 1899.] Tue Corallinaceze form a well-defined group of marine red alge, characterised by the presence of carbonate of lime, the plant-body having a pink, brittle, chalky, or even stony consistence. The group is represented on the coast of Ireland by the genera Schmitziella, Choreonema, Melobesia, Lithothamnion (including Lithophyllum), and Corallina (including Jania). Until fifty years ago these sea-weeds were regarded as animals associated with the corals, and known as Nullipores. Schmitziella has a peculiar habitat, growing in the thick cell- wall of a green alga, Cladophora pellucida, Kitz. Choreonema forms wartlike projections on the joints of various species of Corallina. Melobesia occurs as an epiphyte in colonies of usually minute thin discs on Zostera and various sea-weeds. Lithothamnion and Lithophyllum have a more or less stony aspect, unbranched, or with small warty, or clumsy-looking, or delicate, or even ribbon-like branches. Rockpools—floors and sides—are often completely covered with Lithothamnion species. Corallina is, in some of its species, very common and widely distributed. It has a jointed, branched plant-body. At one time several of the genera were supposed to be the early 1The publication of this Paper was delayed in the hope that the nomenclature of the Corallinacez, on which discussion is proceeding, would haye become more stable. JOHNSON AND Hensman—A List of Irish Corallinacee. 23 stages of Corallina, and to be indicated in it by its disc of attachment. Reproduction takes place vegetatively by the usual Floridean tetrasporangia which, in the Corallinacez, show zonately arranged tetraspores. These asexual organs are like the male organs (antheridia) and female organs (procarps), arranged in groups in small hemispherical, conical, or depressed conceptacles, which open, in some cases, by a single pore; in others, in a sieve-like manner. The eystocarp, or fruit of sexually formed carpospores, is peculiar in its mode of formation, to the group. We obtained confirmation! of the views expressed by Solms Laubach and others as to the mode, in the examination of the cystocarps of Melobesia Coralline, Crn. We had hoped to give an account of our examination of the anatomy of different members of the group, but various duties have compelled us to postpone the matter for the present. The list embodies the result of collections made during the past seven or eight years at different points of the coast. One of us (T. J.), in April, 1891, spent a fortnight on the Fishery Survey boat, 8.S. Harlequin, with the Rev. W.S. Green, F.R.G.s., and made such collections, as opportunity afforded, between Galway Bay and Belmullet. It was during an enforced stay of several hours in Frenchport, to allow the Race round Erris Head to lose some of its force, that the species Melobesia confinis, Crn., a French weed, new to the United Kingdom, was collected. The late Professor W. H. Harvey wrote, fifty years ago, on the economic value of the Corallinaceze of Bantry Bayuetns ** corall sand”’—as a manure.” This coral sand, chiefly composed of Lithothamnion coralloides, is now largely dredged and used in county Cork as a top-dressing for lime for potatoes. In Conne- mara and other parts of the Irish coast similar coralline beds occur. We are not aware of their being utilized elsewhere than in Bantry district. We are indebted to R. J. Moss, F.c.s., F.1.¢., the Registrar and Consulting Chemist of the Royal Dublin Society and to T. S. Porter, Agricultural Superintendent, Irish Land 1 The importance of this confirmation is increased by the just-published discovery of Oltmanns that in Dudresnaya, etc., a second act of fertilisation does not take place. 2A specimen is to be seen in the Botanical Collections of the Science and Art Museum, presented by W. M. Murphy, s.p. The same species occurs on the west coast of France, and is used there also as a manure. 24 Scientific Proceedings, Royal Dublin Society. Commission, for the permission to publish the following analysis of the “coral sand” :— ‘October 21st, 1895. ‘Analysis of sand from Knockboy, county Galway, received August Ist. ‘« Analysis of ‘coral’ from Bantry, received August 6th. ‘100 parts, air-dried, contain :— — Kwocxzoy. Bantry. Moisture, .. As a8 00 0:70 1:38 Iron and Aluminium Oxides, AG “55 “94 ikimes eee ne ie 2 33°26 44-63 Magnesia, .. a as 6 28 3°40 Soda, us a ae 36 1-53 “92 Potash saan ns He A 1-54 36 Silica, 56 ie ave we — 23 Carbonic acid, x ah fi 28°65 37°50 Phosphoric acid, .. e A trace. 06 Sulphuric acid, ae ae at trace. 61 Chlorine, .. es Ne ne 0-18 -76 Organic and Volatile matter*by difference, 4-49 5°50 Sand, insoluble matter, Ns b 28-82 3°71 100-00 100-00 * Containing Nitrogen, als 0-056 0-078 “The Knockboy sample contains 59:4 per cent. of carbonate of lime, and the Bantry sample 79-72 per cent. of carbonate of lime. In the former sample the carbonate of lime is in the form of the débris of sea-shells, and in the latter it is in the form of fragments of corallines. In both samples I have represented the alkalies as oxides, though doubtless they are present to some extent as chlorides. It should be noted, too, that the total alkalies, including those in the insoluble sand, are given in each case. This introduces an error which falls upon the JOHNSON AND HEnsman—A List of Irish Corallinacee. 25 organic and volatile matter; it is inappreciable in the Bantry sand, but may amount to about 2 per cent. in the Knockboy. “In both samples the efficacy of the sand as a fertilizing agent must be attributed mainly to the carbonate of lime; phosphoric acid and nitrogen are not present in sufficient quantity to produce much effect. The Knockboy sand, however, contains a notable quantity of potash in addition to carbonate of lime. This potash would render the sand a valuable fertilizing agent in potato cultivation. ‘“* (Sed.) “«Ricoarp J. Moss, F.¢.8., F.1.C., “« Chemical Analyst, Royal Dublin Society. ‘©THE SECRETARY, ‘¢ AGRICULTURAL DEPARTMENT, _ “Trisa Lanp Commission.”’ The number of species recorded as Irish in Harvey’s Phycologia Britannica (1846-1851) is 18. The useful “ Revised List of British Marine Algz,” con- tributed by Holmes and Batters to the Annals of Botany, 1891, adds nothing to Harvey’s records of the group. This list con- tains some 30-35 Irish species, of which those marked * are additions to the list. There are several forms, not in the list, awaiting more complete material, or comparison with specimens from different seas, for their satisfactory identification. Our work has been materially aided by the Royal Dublin Society, as already mentioned, by the Fauna and Flora Com- mittee of the Royal Irish Academy, as well as by the Royal Society. Our thanks are due to Dr. M. Foslie, through whose hands the Lithothamnion specimens have passed, and from whom the Museum has received a fine set of Norwegian Corallinacec. CORALLINACEAS. *SCHMITZIELLA, Born. et Batt. S. endophiwa, Born. et Batt. Farrihy Bay, county Clare, 1891; Calf Island, county Cork ; Dalkey, county Dublin. 26 Scientific Proceedings, Royal Dublin Society. *CHOREONEMA, Schmitz. Ch. Thureti, Schmitz. (Melobesia Thureti, Born.) Common all round the coast, growing on Corallinu officinalis, C. squamata, OC. rubens. This species was for a long time regarded as an abnormal fruit of C. officinals. MELOBESIA, Lamx. M. confervoides (Lithocystis Allmanni, Phye. Brit.) Malahide, county Dublin (Phye. Brit.); Farrihy Bay, county Clare; Helvick Point, county Waterford.’ We are not altogether satisfied as to the independence of this species, in the absence of reproductive organs. *M. corticiformis, Kitz. Common all round the coast, on Furcellaria fastigiata, Lamx. M. membranacea, Lamx. Rosanoff (“ Recherches anatomiques s. 1. Mélobésiées”’) states that this species is not at allas common as recorded. There is danger of confusing it with If. Lejolisii, Rosan., and I. farinosa, Lamx. In the 8.W. on Cystoseira. General (?). MM. farinosa, Lamx. Roundstone, and other points in the West of Ireland; Helvick Point. Probably generally distributed, growing on Zostera. [IL. verrucata, Lamx. | In answer to our inquiries, M. le Prof. Le Jolis wrote :—“T do not possess any specimens of the enigmatic I. verrucata, Lamx., and my opinion is that such a name should be suppressed. Rosanoff, a very clever and conscientious botanist, who, at my request, undertook here the study of Melobesieze, went to Caen in order to investigate the type specimens of Lamouroux’s herbarium, and ascertained that the specimen labelled J/. verrucata by Lamouroux, is nothing but JL pustulata.” 1 We have been helped in the examination of the S.-E. Collections by Miss M- C. Knowles. JoHNSON AND Hensman—A List of Irish Corallinacee. 27 *M. Lejolisii, Rosan. Roundstone; Bear Island, Bantry Bay. This species is more or less distinguishable, to the naked eye or by the pocket lens, from I. membranacea, Lamx., which has larger conceptacles, more sharply marked off from the thallus. Microscopically MM. Lejolisti is distinguished by its hair-beset conceptacular pore. : MM. pustulata, Lamx. This species occurs all round the coast, especially on Phyllo- phora rubens, Grev. *M. macrocarpa, Rosan. Bear Island. : This species is easily mistaken for IW. pustulata, being distin- guished from it by having bisporous tetrasporangia, not tetrasporous ones, as in W. pustulata. *M. Laminarie, Cru. West of Ireland ; Dungarvan. This species is common on stalks of Laminaria, in Dungarvan Bay, forming thick, brittle, pink incrustations on the stalk, and must add largely to the manurial value of such Laminarias. *M. Coralline, Crn. This species has been collected nearly all round the Irish coast (not between Howth and Raven Point, the least examined stretch of coast for marine alge generally). It forms thick, lumpy expansions on Corallina officinalis, with conceptacles not much projecting. *M. confinis, Crn. Frenchport, county Mayo. Forms small, slightly thickened, hard swellings on C. officinalis, and on limpet shells; has vertically elongated thallus-cells and bisporous tetrasporangia. LITHOTHAMNION, Phil. Sub-Gen. HurirpoTHamnion, Fosl. Section I.—Innatee, Fosl. *Tithothamnion fruticulosum (Kiitz.), Fosl. Roundstone, M‘Calla; Great Man’s Bay. 28 Scientific Proceedings, Royal Dublin Society. *Z. apiculatum, Fosl. (?) Very nearly related to ZL. tophiforme, Unger; needs further examination. Roundstone. *L. coralloides, Crn. f. flabelligera, Fosl. Dalkey; Belfast. This Coralline is abundant in Dalkey Sound; was also dredged by us in Belfast Lough, off Carrickfergus ; and has been collected by Batters, off Bute, in Scotland. J. australis, Kosi. J. subsimplex, Batt. West of Ireland. *I.. colliculosum, Fosl. Roundstone, M‘Calla; West of Ireland. L. polymorphum (L.), Areschg. Bundoran ; Belfast; Ireland’s Eye; Dalkey Sound. This species has given algologists a great deal of trouble, and has been mistaken constantly for Z. incrustans (Phil.), Fosl. *L. incrustans (Phil.), Fosl. Gola Island, county Donegal; Bundoran; Frenchport; Aran- more; Roundstone, Farrihy Bay; Kilkee, and many other points on the west coast of Ireland; Baltimore; Ballinacourty ; Ireland’s Hye. A common species. LL. fasciculatum, Harv. Roundstone, M‘Calla; west of Ireland; dredged off Schull ; Ballinacourty. The locality near Schull was indicated to one of us by a coast- guard officer at Baltimore, who had brought up “red clinkers”’ when oyster-dredging off Schull. LL. calcareum (Hary.), Areschg. Donegal Bay, off Killybegs; Roundstone, M‘Calla; Great Man’s Bay; Valencia Island; and many other points on the west coast. JOHNSON AND Hensman—A List of Irish Oorallinacee. 29 Foslie finds it difficult to determine the exact limits of Harvey’s Melobesia calcarea, and considers M‘Calla’s Nullipora compressa a variety of the present species. Our specimens of L. coralloides, f. flabelligera, agree very well with the figures of Nullipora compressa in Johnstone’s “ British Sponges and Lithophytes,” and come from the same locality. The circumstances of the loss of the collection of specimens of Coralli- nacee made by M‘Calla, and utilized by Harvey for description and illustration in Phycologia Britannica, have recently been described by Dr. H. P. Wright (‘Notes from the Botanical School of Trinity College, Dublin, 1896”). The M‘Calla Collec- tion, in the charge of one of us, had the labels rewritten some time. before we saw it, and is unfortunately not now, to this extent, authentic. *Z.. dentatum, Kitz., with *Z. Hauckii, Fosl. (ZL. mamillosum, Hauck), the latter partly covered with Z. incrustans (Phil.), Fosl. Roundstone, M‘Calla. LL. agariciforme, Areschg. Roundstone, M‘Calla ; Roundstone, 1893. This interesting and extremely local species is still to be got by dredging on the coral bank in Roundstone Bay. Section I].—Evanidee. *L. tophiforme, Unger (?). Roundstone, 1893. *I. Sonderi, Hauck. West of Ireland; Ireland’s Hye, 1896. *L.. circumscriptum, Stromf. West of Ireland. *L. laevigatum, Fosl. Go Island, county Donegal; and West of Ireland. *L. Stromfeltii, Fosl. Common in Ireland. 30 Scientific Proceedings, Royal Dublin Society. Sub-Gen. LirHopHyiivm (Phil.), Fosi. *D. Lenormandi (Areschg.), Fosl. Bundoran; Aranmore; Cave Islands; Bear Island; Baltimore; Dalkey Sound; Balbriggan ; generally round the coast. L. lichenoides (Phil.). Roundstone ; Miltown-Malbay; West of Ireland; Calf Island. Generally round Ireland; common in the west and south-west, as Harvey supposed. CORALLINA, Lamx. C. officinalis, L. Common all round the coast. C. squamata, Ellis. Not uncommon all round the coast. *C. mediterranea, Areschg. Ballydonegan Bay, and Baltimore, county Cork. Distinguished from C. officinalis, of which Hauck regards it as a variety, by having one or more—one- to several-jointed, antenna- like outgrowths on the conceptacles. C. rubens, Ellis et Sol. Common round the coast, as is C. rubens f. corniculata, Hauck. Cee JIN NOTES ON A METHOD OF COMPARING THE RELATIVE OPACITIES OF ORGANIC SUBSTANCES TO THE X RAYS. By ERNEST A. W. HENLEY, B.A. [COMMUNICATED BY PROFESSOR GEO. FRAS. FITZ GERALD, F.R.S., F.T.C.D. | [Read DEcEMBER 21; Received for Publication, DecemBeEr 23 ; Published January 21, 1899.] In the following experiments, the method adopted was one which was suggested to me by Professor FitzGerald. A piece of the substance under examination was cut in the form of a right-angled triangular prism, and placed with its base over a photographic plate enclosed in a light-tight bag which was separated from the wedge by a thin sheet of celluloid, so as to prevent any moisture reaching the plate. Beside this wedge-shaped piece, another of the same dimensions, but of different material, was similarly placed, with its thin edge in the same straight line with the edge of the first wedge. The two wedges were then photographed by the X rays. On examining the negative, a gradual increase in the opacity of each wedge from the thin end towards the thick end was observed, as might be expected. Several prints of varying depths of colour were taken from the negative, and then the actual process of measurement commenced. ‘The prints were cut at right angles to the thin edges of the wedges, and part of the photograph of one substance was placed in apposition with that of another sub- stance. Now, if the substances under examination had the same opacity to the X rays, then, for points equally distant from the thin edges of the wedges, equal depths of colour would be observed. Tf, on the other hand, a certain substance A was more opaque to the X rays than another substance B, then, to obtain equal depths of colouring, it would be necessary to go back farther from the edge of the wedge B than from the edge of A. In the case of wedges of the same dimensions, the thickness at any point is pro- portional to its distance from the thin end of the wedge, measured along its base line. 32 Scientific Proceedings, Royal Dublin Society. The substances examined by this method were bone, muscle, and fat, taken from the sheep. The maximum thickness of the wedges varied from one to two inches. It was necessary to freeze the materials so that the wedges might be accurately cut. No attempt was made to secure a uniform current in the 10-inch Ruhmkorff coil used, as measurements were only made in the case of wedges which had been exposed at the same time and on the same plate. The time of exposure varied from one to three minutes. Only photographs of the central strip of each wedge were used, as shadows of the edges of the upper surface were thrown on the plate, owing to the obliquity of some of the rays. The time of exposure was varied, as well as the depth of colour in the prints, so as to obtain the greatest diversity of conditions. The lighter-coloured prints were found to be the most satisfactory for purposes of comparison. Some of the wedges compared were of different sizes; and in such cases, a vertical section of each wedge was drawn to scale on paper, and the thicknesses corresponding to different distances along the base line in each wedge were easily obtained. The first comparison was made between muscle and fat. As the result of seventeen measurements made on different prints from various negatives, the ratio of the opacities of muscle and fat was found to be 2°5: 1. The next comparison was made between bone and muscle. In the case of bone, variations occurred according as the specimen contained different proportions of cancellous tissue and of compact tissue. The results given are the mean of all the measurements. The ratio of the opacity of bone to that of muscle was found to be 1:6: 1, as obtained from eleven measurements. ‘This result, when combined with the previous one, gives the ratio of the opacity of bone to fat as 4: 1. Hence, the numbers obtained, as representing the relative opacities of bone, muscle, and fat, are 4, 2°5, and 1. P38) V. THE KIESELGUHR OF COUNTY ANTRIM. By JAMES HOLMS POLLOK, B. Sc. [Read, January 18; Received for Publication, January 21 : Published, Marcu 13, 1899.] Some considerable time ago I received from Mrs. Hartley a sample of Kieselguhr from county Antrim to exhibit at the Conversazione of the Royal Dublin Society. Afterwards I noticed, in Pliny’s “Natural History,” the remarkable statement that the Romans were acquainted with a brick that floated. The passage says :— “‘ At Pitane, in Asia, and in the cities of Maxilua and Calentum, in Farther Spain, there are bricks made which float in water when dry, the material being a sort of pumice earth, extremely good for the purpose when it can be made to unite”; and in the Bohn edition there is a footnote saying these bricks have been imitated by Fabrioni with a light argillaceous earth found in the territory of Sienna. It occurred to me that the floating bricks of ancient Rome could probably be reproduced from the county Antrim Kieseleuhr, and on trial it made a brick that floated exceedingly well when first placed in the water, but soon absorbed water and sank, exactly in accordance with Pliny’s statement. By coating the bricks over with a thin skin of paraffin wax to prevent absorption of water they are rendered permanently buoyant. An analysis was then made of the specimen I had received, and its composition found to be:— Per cent. Silica, . ‘ ‘ ; Hey) Alumina, é : 3 9°8 Ferric Oxide, : ; 5:4 inte sae : e ; 1:5 Magnesia, . : 0-1 Water and Organic Matter, 12-0 Sr SCIEN. PROC. R.D.S., VOL. IX., PART I D 34 Scientific Proceedings, Loyal Dublin Society. T am indebted to Mr. R. G. Norman for many specimens of Trish and other Kieseleuhrs which I have examined. Under the microscope the Kieselguhr from county Antrim presents a very pretty appearance, showing innumerable little cubical box-shaped diatoms, alsolittletubs or drums in less quantity, anda few elongated and boat-shaped diatoms, apparently of the kind known as pinnu- larize and Navicula Westii ; there are others of a star or radial shape, but the neatly shaped cubical boxes are the predominating form. A curious fact was noted that in focussing for the boxes the large boat-shaped and radial diatoms almost disappeared, and that when they were brought out clearly the boxes became very indistinct. On measurement the width of the little box-shaped diatoms is found to be about 34, mm. This illustration shows the highly magnified image of the box and tub-shaped diatoms. The raw Kieselguhr, as cut from the deposit and sun-dried, has a specific gravity of ‘5422; when moulded in a brick, and burned at a very low temperature, it was found to have a density of 8073. When burned at a somewhat higher temperature it takes a light red colour, and has a density of :7691. A piece of burned Kieselguhr of 54:87 grams absorbed on immersion 88 grams of water, having then a weight of 92°87 PoLttoK—On the Iieselguhr of County Antrim. 35 grams, and its actual volume was 68 cubic centimetres, correspond- ing to a density of 8069. If we may take the volume of the water absorbed as a measure of the porosity, we see that every 100 c.c. of Kieselguhr has pores of a total capacity of 55:9 e.c. for absorption of liquids of any kind. It is interesting to note that this would give an absolute density of the solid skeleton of the IGeselguhr of 1-829, the density of solid quartz being 2°6, but we have no right to suppose that the pores when treated as above are fully saturated. In July of 1898 I visited Toome Bridge, and found that the deposit was being worked on the east bank by Messrs. J. and F. Grant, who gave me every opportunity of examining the character of the deposit, and to whom I am indebted for the following analysis of the deposit at this point. ANALYsIs OF KiksELGUHR FRoM T'oomE Bripee, County ANTRIM. Sample from the Middle of the Deposit. As Received. Calcined. Silica (soluble),. : : ‘ 5 57°12 per cent. 66°50 per cent. Silica (insoluble), ; : : : NG) g IBID 55 Alumina, : : : : : So) be OH op Oxide of Iron, . d : : : BAN) 6, 24s Lime, AEE Re Se CEE NA 1B. Magnesia, : : ‘ : : OSS og 0-96 Ge Alkalies, ; 5 : : F 052. Siuaes O38 55 Organic Matter and Combined Water, eae 7 5 — is Moisture, ; : : : 5 Gos) a. — Bs 100:00,, HOOWO gp At Toome Bridge the deposit is some four feet thick ; and, after cutting and drying in the sun, the Kieselguhr is of a very white colour, with a few roots through it, but otherwise exceedingly pure and, after drying, of surprising lightness. The deposit, as it rests on the top of peat, and is covered only by vegetation, is obviously of exceedingly recent formation. It extends all along both banks of the lower Bann, from Toome Bridge, where the river emerges from Loch Neagh, right down to Coleraine. At Toome Bridge the deposit, so far as one can judge by superficial indications, and without actually proving D2 36 . Scientific Proceedings, Royal Dublin Society. by digging, extends some two miles west of the Bann, then narrows in the form of a great triangle, towards Coleraine. It is absolutely flat, only a few feet above the level of the Bann, and at such a height that it would ke covered at times of inunda-- tion. Rocks and stones that are covered when the Bann is in flood have on them a thin skin of diatomecious deposit, so that one is irresistibly led to the conclusion that the deposit is laid down when the Bann is flooded, and that the deposition is going on now. That the water, highly charged with silicious skeletons of diatoms, comes pouring out of Loch Neagh, and deposits this infusorial earth in the quiet waters of the flooded portions. The great store- house of the Kieselguhr is Loch Neagh itself, and the deposit on the banks of the Bann is as nothing to the immense deposit there must be on the bottom of the Loch. Of course this is a point that cannot be finally settled by speculative considerations such as the above, but must be determined by actual dredging, which will mean a certain amount of expense. The commercial uses of Kieselguhr are numerous, firstly, for dynamite, but the dynamite manufacturer states that the particular forms of the organisms in the county Antrim IGeselguhr are not those best suited for making dynamite, a tubular form giving, I am told, the best explosive effect. Mieselguhr, however, has many other uses for which thousands of tons a year are required, and are now shipped from the Continent to London. It is one of the best non-conductors of heat and sound, and is superior to all other materials for covering boilers and steam-pipes, for lining fireproof walls, floors, safes, and refrigerators, and its extreme lightness should specially recommend it for all such uses on board ship, and especially for lining fireproof bulkheads, for which one would imagine a very ready market would be found at Belfast if it were put in the proper form for consumption. Grusp—Time Signals. 37 VI. ON THE CORRECTION OF ERRORS IN THE DISTRIBUTION OF TIME SIGNALS. By SIR HOWARD GRUBB, F.B.S., Vice-President, Royal Dublin Society. (Puares IV. and V.) [Read Novemser 16; Received for Publication Novemser 21, 1898 ; Published Marcu 25, 1899.] Havine had occasion lately to inquire into the merits of the various existing systems of synchronizing clocks, and to report on the best arrangements to be made suitable for a large Municipal Institu- tion in one of the larger English towns, I have thought that it might be interesting to the Royal Dublin Society if I placed be- fore them the results of my inquiries and the conclusions at which I have arrived, more especially as the conditions existing in the Institution referred to are, in many ways, very similar to those in the Royal Dublin Society, though on a larger scale. It is hardly necessary, at this period of the nineteenth century, to enlarge on the importance of having correct time available; and the Royal Dublin Society recognised this many years ago by estab- lishing a system of synchronized clocks in Dublin, controlled from a central clock in this house, which clock was itself checked by a daily signal from either Greenwich or Dunsink. The controlling of the outside clocks throughout the town was effected by sympathetic pendulums of the “ Ritchie ” type, and the system worked well at first; but in time, as the telegraph and tele- phone wires accumulated in the city, the induction produced in our wires from the strong currents in the adjacent wires caused such serious trouble and irregularities as necessitated the abandonment of the system. This has been the case also in many other towns. The conditions present in the Institution on which I have lately had to report are, as I said, somewhat similar to that of the Royal Dublin Society (not taking into account any outside clocks); that is to say, itis a building unconnected with any Observatory, and unsuit- able for the erection of transit instruments, and therefore has to depend ultimately on a daily signal from Greenwich. It contains some 200 rooms, each requiring a clock face which it is desirable 38 Scientific Proceedings, Royal Dublin Society. should synchronize with the central or standard clock, and show as nearly as possible the true time. Under these circumstances I made the following recommenda- tions :— The installation naturally divided itself under three heads— (A)—A. standard clock, of best procurable make, placed in such a position as would ensure its protection as far as possible from climatic or other changes, and furnished with elec- trical connexions suitable for the control of — (B)—A strong piece of uniform motion clockwork automatically controlled at stated intervals (say, every 15 seconds) from A, and further checked and controlled once in every 24 hours by the Greenwich signal received through the Post Office: this piece of mechanism to be enclosed in a glass case exposed in some prominent position (say, in the entrance hall), supplied with dials and hands, and arranged also so as to serve as a distributing clock for driving. (C)—A. series of, say, 200 dials distributed throughout the building, each being furnished with minute and hour hands, and the necessary dial work, actuated once a minute only from the distributing clock B in the entrance hall. The distributing clock B in the hall, being automatically con- trolled once in every 15 seconds from the standard clock, may be depended upon to keep as accurate time as the standard clock itself, hour by hour; while, to prevent any accumulation of small errors which might, in the course of some days, reach an incon- venient amount, there is the further check by Greenwich signal at 10 a.m. or 1 p.m. every day. Any error that exists on receipt of this. signal is not only wiped out at once automatically, but the amount of this error is registered on a paper tape for after-reference, if desired. The maximum error that can exist, therefore, cannot be greater than the rate + or — of the standard clock for 24 hours; while, after the receipt of the Greenwich signal, the clock B may be relied on to within a fraction of a second. Grupp—TZime Signals. 39 I here append details of the construction of the three parts, A, B, and C:— (A).—Should be the best procurable timekeeper, preferably with a gravity escapement, and furnished with an arrangement which would make a delicate electrical contact once in every 15 seconds. Such a clock, mounted in the ordinary way, should give an excellent result; but still further to ensure accurate working, I would propose that this clock be enclosed in an air-tight case after the manner adopted by Professor Becker, of Glasgow, by which the pressure is kept constant, and this case placed in another, duly pro- tected by non-conducting material, and the whole mounted within its double chamber in the basement of the Institution, so that it would be practically free from both barometric and thermometric changes. Such a clock should have very small e77o0s, but no clock is without some small safe. The rate+or—of a clock must not be confounded with its errors. The very best clock, and that with the smallest error, may have a fairly large rate; that is to say, it may give 86,401, or 86,399 secs. in the 24 hours instead of 86,400, but may preserve that rate steadily, day by day, without any sen- sible error from that rate. This is not serious for one day, but if allowed to accumulate for a week or a month, it is; and it must be remembered that a clock like this standard clock A, being sealed up in a case, cannot be readily got at for re-setting; therefore it is that I propose to depend on this clock, accurate though it may be, for only 24 hours at a time, and have made arrangements in the part B to have this—the distributing clock—checked and auto- matically corrected by a Greenwich signal, an automatic registra- tion being made each day of the extent of the correction of the standard clock A. Another trouble with sealed-up clocks has sometimes been experienced—I refer to the gradual oxidation after a lapse of time of the electrical contacts. ‘lhis will probably not be serious with the very small current necessary; but if desired to ensure against failure in this respect, I would recommend that the air-tight case of the standard clock be enclosed in another larger one, forming a jacket, both the clock case and its jacket being filled with nitrogen 40 Scientfiic Proceedings, Royal Dublin Society. gas instead of air; no oxidation can be possible in the absence of oxygen. ‘The nitrogen in the jacket can be occasionally renewed without affecting the inside chamber, and as the inner chamber is always surrounded, as well as filled, with nitrogen, no evil effects - can ensue from diffusion. (B).—This portion of the apparatus is novel, and I therefore submit a design and detailed description. (See Plate IV.). It consists essentially of a uniform motion clock somewhat similar to what we use for our astronomical telescopes. This clock serves to drive two spindles, the first at a rate of once in 15 seconds, and the other once in 60 seconds. On the 15-seconds spindle, there is a controlling apparatus very similar to what we use on our equatorials, by which the rate is checked every turn, 7e., every 15 seconds; and if there be any difference between this clock and the standard clock amounting to even one-tenth of a second, one or other of the correcting differential gears (0 or U’) is brought into action, and this error is wiped out, This spindle (A) may therefore be assumed to revolve exactly in accord with the standard clock A. On the 60-seconds spindle (B) is a similar correcting arrange- ment, which, however, only comes into play once in 24 hours, viz., on the arrival of the Greenwich signal, and its duty is to wipe away any difference + or—that may be present between the time as given by Greenwich and that given by the standard clock, and to register this on a paper slip for after-reference. This corrected 60-seconds spindle (B) is used, first, to show correct time on a suitable dial or set of dials in the hall, and, secondly, to drive or control all the 200 clocks in the various rooms of the building. (C).—For the distribution of time throughout the building, there is the choice of various systems. There is the pneumatic system and the electrical system, and the latter can be again divided into a system which regulates or controls clocks possessing a certain motive power in themselves, and that which actually drives the whole series of clocks by elec- trical impulses. Any of these systems can be worked from the distributing clock described under head B. Grusp— Zime Signals. 41 The pneumatic system possesses the great advantage of being quite independent of any electrical currents in adjacent wires, which currents sometimes cause great trouble by producing in- duced currents in the electrical wires to the clocks. I was at first inclined to recommend this system, but as the currents in most of the service wires in the new Institution will be, I am informed, constant, and not intermittent, this objection does not apply seriously ; besides which, I find, on ex- amination of the pneumatic system, as carried out in Paris, two serious objections— (a). It has apparently been found necessary to transmit the power, not by a sudden pulse of air, but by gradually filling the whole system of tubes with compressed air, the operation taking about 20 seconds, and then allowing this to flow out again during 40 seconds. Consequently the movement of the clock hand may take place anywhere within this 20-seconds period, and this, though accurate enough for domestic purposes, would not suffice for some of the purposes for which these clocks may be used. (0). I find that the air-compressing and distributing apparatus is extensive, complicated, and costly for small installations. 'There- fore, I do not see my way, at present, to recommend it for this particular case, notwithstanding its obvious advantages in other ways. As regards the electrical system of distribution :— There are many excellent systems in the market by which pionks, having motive powers of their own in the form of weights, springs, &e., can be regulated and cor- rected from a central clock, and almost any of these, except the sympathetic pendulum clocks, would be found suit- able. (Fig. 7.) [Tor figs. 1-6, see Plate VJ ; That which I would prefer is the elock which is furnished with a forked lever placed over the XII on the dial, which lever is momentarily brought down, at each hour precisely, by a current from the distributing clock, and sets the minute-hand right (if it be wrong) by the impact of the Fic. 7. 42 Scientific Prececdings, Royal Dublin Society. A-shaped fork against a pin on the minute-hand. ‘This is simple, inexpensive, and very reliable. Any clock of this form, however, requires winding periodi- cally; and if it be desired to avoid this, one or other of the second — class of electric clocks which do not require winding must be used- There are many varieties of these also in the market, but I cannot say that any of them are certain to prove satisfactory. It is much more difficult to keep a clock going correctly when it has no driving power of its own, and when the work of driving, as well as regulating, has to be done by the electric current. There are some excellent clocks of this description in‘ the market, but if must be remembered that there is one great differ- ence between the working of these driven clocks and that of the first-mentioned clocks, in which the regulation only, and not the driving, is effected by the electrical current. In the latter, if the current at any hour fails from some cause to do its duty (and in electrical arrangements of the very best order this will sometimes happen), the only result is that, at the next hour, the correction to be made will be double that which would have been required if the former current had acted rightly ;. and the error in the clock before that correction will be double that which it would have been for the one hour; but as the error for two or three hours run must be very small, and as it is wiped out completely by the first current that comes after the Juilure, this is of little consequence. In the former case, however (that of the driven clock), any error that occurs is not wiped out by any of the succeeding cur- rents, but remains there until set right by human agency; and if the errors, though only occasional, be (as is likely). mostly of the same character, ¢.e., gaining or losing, they will accumulate, and in time amount to a serious quantity. For the above reasons I would recommend for this purpose, where convenient, the adoption of clocks which have a motive power of their own, and which only depend on the central clock for periodic correction of any accumulating errors; or if, as is. sometimes the case, it is highly desirous to avoid the necessity of periodic winding, clocks of the self-winding principle may be used, corrected periodically from the central or distributing clock. Grupp— Time Signals. 43 In the case under consideration, however, where the number of rooms, and therefore of clocks, amounts to so large a number as 200, it is evidently important to simplify and keep down the cost of each individual clock; therefore, it will probably be found more economical to run an additional wire through the various rooms, and use two distinct currents, one of which will supply the small necessary motive power for driving the wheelwork, which, in this case, may only mean the few wheels and pinions necessary for the dial-work; and the other current to work, once a minute, the escapement which allows the hands to move forward at each minute. This latter arrangement has many advantages; and it can easily be arranged that an overplus of winding power be sup- plied, so that even if there be one or two, or even five or six, misses in each minute, there will still be ample left to do the necessary work, and there need be no error. As it is very unlikely that a greater number of failures than this will ever occur in one minute, practically the only danger is, that of the other or minute current missing—that which allows the hand to move forward. As there are only 1442 of these in the 24 hours, as against 86,400 of the others, the danger is pro- portionately less; but to avoid even this danger, I have devised an arrangement by which, if the minute current should by any chance fail, the escapement will be let off mechanically a second or so- after it ought to have been let off electrically, the result being, that that particular minute will be late by one or two seconds, but there will be no cumulative error, and when the next minute eurrent comes it wipes out the error completely. In this clock, therefore, it is possible to actually disconnect the wires for several seconds during any part of the minute, and still the clock will show correct time. I would suggest that this last form be used in the more important positions, and the simpler form for the rest. [Expianation or Puares. 44 Scientific Proceedings, Royal Dublin Society. EXPLANATION OF PLATES IV. AND Y. In Plate IV., AA is a shaft which is in direct connexion with the 15-seconds shaft of the uniform motion clock, and revolves approximately at that rate. A toothed wheel, No. 1, is fixed upon this shaft; all the other wheels, with the exception of Nos. 7 and 8 at the other end, are loose upon the shaft. Wheel No. 2, which is cast in one piece with No. 3, is cut with a slightly different number of teeth from No. 1, and is driven from it by means of the pair of pinions, yp, which act as couplers so long as the rate is normal; if, however, the disc 6’6’ is arrested momentarily, the motion is conveyed from No. 1 to No. 2 through the pinions yp, and consequently a slight differential rate is produced, as Nos. 1 and 2 have not quite the same number of teeth. The same description applies to Nos. 3 and 4, the result being that a momentary stoppage of the disc 4 d causes a slight acceleration of the rate of the rest of the moving parts, including wheel No. 6; whereas a momentary stoppage of 0’ d’ causes a slight retardation. No. 6, shown in black, is an ebonite ring, mounted with a pair of nearly half circles of silver shown enlarged in fig. 4, Plate V. No. 7 is alight metallic dise with a notch or notches, better shown in figs. 2 and 4, Plate V. (c) is an electro-magnet with an armature better shown in fig. 2, Plate V. This armature is worked from the sealed or standard clock through the relay (f), shown enlarged in fig. 8, Plate V., and the tooth of the armatures of this electro-magnet engages into the notch on wheel No. 7, and will not allow that wheel to revolve so long as it is engaged, A current is sent into the electro-magnet (c) every 15 seconds from the standard clock. Ifthe uniform clock has gone correctly, that current occurs at the moment that the V notch comes opposite the V on armature. If the uniform motion clock has gone either fast or slow, the notch will not be exactly opposite the tooth; but when the current arrives, the impact of the tooth on the side of the V notch, in wheel No. 7, sets that wheel, which is driven only by friction, backwards or forwards the necessary quantity. By means of this device, the revolutions of the disc No. 7 are con- trolled from the standard clock, and kept in an exact uniformity at every 15 beats of the pendulum. Fig. 4, Plate V., shows that the disc No. 7 has mounted upon it a small arm which plays round the silver half rings on the ebonite disc. Grupp— Time Signats. 45 In the normal state, the contact of this arm with the silver-shod dise - occurs in the break between the two silver rings, where a small piece of agate is inserted; but if the shaft AA has revolved too quickly or too slowly, and thus has necessitated an alteration of the position of the disc No. 7, the contact finger moves off from the agate block to one or other of the silver half-rings which forms an electrical connexion with the accelerator or retarder, d or a’. These remain sufficiently long in action to correct the error and bring the contact pin on to the agate block once: more. By this means, which is practically the same as what I have used with such success for many years past on my equatorial telescopes, I can ensure that the corrected portion of the apparatus on the shaft AA keeps: time as accurately as the standard clock which controls it. BB is a second shaft worked from the first by a pair of wheels of 4 to 1, and revolves once ina minute. This second shaft is supplied also with a pair of correctors and a checking arrangement worked, so far as this is concerned, only once in 24 hours, through a relay which receives the Greenwich signal. There isno occasion to describe this second shaft, as it is practically identical with the first, its duty being to remove, every 24 hours, any difference that may exist between the time given by the standard clock and that of the Greenwich signal. Without this second shaft, the rate of the clock would be exactly that of the rate of the standard clock which controls it, and which would, no doubt, be excellent day by day; but the reception of the Greenwich signal and the automatic corrrection of it by the apparatus on this second shaft ensures that this clock will never be different from the true time as emanating from Greenwich by a quantity greater than what the standard clock errs in 24 hours. Fig. 5, Plate V., shows a modified arrangement of fig. 2, by which the accelerator is dispensed with. The clock is given a slight gaining rate, and, consequently, it is only necessary to provide a retarder. Fig. 6, Plate V., shows the suggestion for recording the amount of error in the standard clock every day. A tape of paper is arranged to pass round a roller which, in a general way, is not in contact with any- thing on the reyolying shafts, but if either the accelerator or the retarder comes into action for any given number of seconds (say 5 or 6 seconds), this roller carrying the tape is pressed against another roller on the revolving shaft, and a capillary tube filled with ink draws a mark upon the tape, the length of which corresponds to the amount of correction which has been necessary to bring the clock into synchronism with Greenwich. Two of these capillary tubes would be provided, one to show the + error, and the other the — error. [ 46 | VIL. PROPOSAL FOR THE UTILIZATION OF THE ‘«‘ MARCONI” SYSTEM OF WIRELESS TELEGRAPHY FOR THE CONTROL OF. PUBLIC AND OTHER CLOCKS. By SIR HOWARD GRUBB, F.R.S., VICE-PRESIDENT, R.D.S. [Read January 18; Received for Publication January 21; Published Marcu 25, 1899.] In a Paper read before this Society last November on “ The Correction of Errors in the Distribution of Time Signals,” I described a scheme of time distribution suitable for a large in- stitution containing some two hundred rooms, all of which it was desirable to have furnished with clocks synchronized with one another, and controlled from one central clock. This central or distributing clock was itself to be controlled from the best procurable standard timekeeper placed under exceptionally favour- able conditions, and was further checked and corrected once every twenty-four hours by an electric signal from Greenwich Observatory. The scheme proposed in the Paper referred to dealt only with the control of clocks in the one building, but I incidentally mentioned that the Royal Dublin Society had some years ago established a system of synchronized clocks in Dublin controlled from a central clock in this building, and that for some time this system worked satisfactorily, and proved a great convenience to the citizens, but with the introduction of the telephone system, and the multiplica- tion of the telegraph wires, troubles arose from induction and other causes which finally necessitated the abandonment of the system. Adventitious currents produced by induction or other causes which, in the case of telephone and telegraph circuits, produce but a slight error or gap in the messages, cause errors in synchronized clocks which remain permanent until corrected by human attention, and practically destroy the value of the installation. Grupp—Control of Public and other Clocks. AZ In working out the scheme above referred to, it seemed to me a pity, if such a perfect installation should be erected in a public building in the midst of a large city, that advantage could not be taken of it by those living or having their houses of business in the vicinity, and I therefore naturally looked about to see if I could find any system that would be free from the disadvantages of that which was tried and abandoned in Dublin and other cities. Having taken an active interest in the work of the Committee appointed by this Society to carry out the scheme of clock control in Dublin, I was fully aware that this scheme was only abandoned after most careful and searching investigation of all the various systems then available; I refer to a period about fifteen years ago. It then occurred to me that possibly the system of Wireless Tele- graphy, which has lately been raised from the sphere of a laboratory experiment to that of a practical achievement by the invention of Signor Marconi, might be utilized, and a little investigation has convinced me that his system is particularly well adapted for this purpose, and is free from all the disadvantages which caused the abandonment of the other systems. Looking back at the various failures we had in the old system, I find they may all be said to be due to one or other of three causes :— (1) Induced currents in the clock wires, mainly produced by currents in adjacent telegraph or telephone wires. (2) False currents, or failure of currents produced by short circuiting of the clock system, generally caused by telegraph line-men erecting or repairing adjacent wires, and drawing one wire over others, &c. (3) Failure of current owing to improper action of some of the users of the system. It not infrequently occurred that on failure of the current, it was found that some user had entirely disconnected his wires for the purpose of repairing his clock, thus disarranging the whole system. Now let us consider what effect these would have when using the “Marconi” system. (1) The nature of the high-frequeucy currents is such that they are not in any way affected by currents in adjacent wires. 48 Scientific Proceedings, Royal Dublin Society. (2) As there are no wires, this cannot take place. (83) Each user is absolutely independent of all others, and he cannot by any action of his own interfere with the efficiency of any — one else’s apparatus. It therefore appears that this system is exceedingly well fitted - for this particular work, and I hope it may be allowed a fair trial before long. The whole arrangement would be of exceeding simplicity. In some central position in a town a standard clock would be fixed whose duty would be that of starting at stated intervals a generating apparatus such as is used by Mr. Marconi, and which, consists mainly of a strong induction coil. The current having been turned on to this for a fraction of a second causes a spark of high tension to pass between the terminals. Instantly an electrical wave is transmitted from this centre and passed over the town, its influence extending a greater or less number of miles according to the strength of the current. Each establishment that is included in the system is furnished with one of Mr. Marconi’s exquisitely delicate little “ coherers,”’ and a relay with a small local battery to work the correcting apparatus (of whatever nature it may be) for setting his clock. As the electrical wave passes, the coherer is excited, the relay is attracted, bringing the local battery into action, that particular clock is set, and any error that may have existed is entirely wiped out. There is something very beautiful in this action of the “Marconi”? wave. In a city supplied with this apparatus we should be conscious as we hear each hour strike that above us and around us, swiftly and silently, this electrical wave is passing, conscientiously doing its work, and setting each clock in each establishment absolutely right, without any physical con- nexion whatever between the central distributing clock, and those which it keeps correct by means of this mysterious electrical wave. We might go even still further, and though I do not put it forward as a proposition likely to be carried out in any way, except as an experiment, yet it undoubtedly would be perfectly possible to carry an apparatus in one’s pocket, and have our watches automatically set by this electrical wave as we walk about the streets. GruBpsp—Oontrol of Public and other Clocks. 49 As to the best arrangement of correcting apparatus to attach to our clocks. Once we have the relay in our houses worked by the electrical wave, we can use it (the relay) to work any kind of apparatus we choose. I would prefer for all commercial and social purposes that only one wave be sent per hour, and that the cor- recting apparatus be of the simplest possible form such as described in my Paper read last November. It will be observed that, in this arrangement,! even if a current fails for one hour, the only fault will be an error in the clock for the succeeding hour, but the next wave that comes wipes this out, and there can be no cumulative error. I think it will be evident to anyone who has followed my remarks that the system of synchronizing clocks by the “Marconi’”’ wave is a perfectly practicable one. For convenience of exhibition we have necessarily had to place the distributing arrangement and the receivers within the same building, but it will be easily understood that the same influence which has been so successfully working this Morse pen, and send- ing messages through it every day, for months past, eighteen miles across the sea, from Alum Bay to Bournemouth, is quite capable of working this other equally simple apparatus for synchronizing clocks, and that, in fact, if the clocks in Bournemouth were supplied with the necessary receiving apparatus, they could all be checked, and kept to correct time by a standard clock in the Isle of Wight. It will be observed that in the course of my remarks I have spoken only of the “Marconi” system of Wireless Telegraphy. It may be asked whether this is the only system available. I have had no experience whatever with any other form of wireless telegraphy. It may be found possible to work with some other, but I have confined my, remarks to the “ Marconi” system because, as I have said before, while other systems can hardly be said to have emerged from the experimental stage, the “‘ Marconi” system of wireless telegraphy is an accomplished fact. 1 A practical illustration was here given of the proposed arrangement. SCIEN. PROC. R.D.S., VOL. IX., PART I. E leo" VIII. ON A HYDRO-DYNAMICAL HYPOTHESIS AS TO ELECTRO- MAGNETIC ACTIONS. By PROFESSOR GHORGE FRANCIS FITZ GERALD, F.RB.S. [Read DecemBEr 21; Received for Publication DecemBer 23, 1898 ; Published Marcu 25, 1899. ] For many years I have been advocating the hypothesis that the ether is of the nature of a fluid full of vortical motion, and that electro-magnetic actions are due to particular arrangements of this motion, which is, in general, irregular or at least undirected. Some years ago, Lord Kelvin, at a meeting of the British Association, and subsequently in the Phil. Mag., ser. v., 1887, vol. Xxiv., p. 842, published an investigation as to a possible transfer- ence of laminar wave disturbance through a turbulent liquid. He was not satisfied with the investigation, principally, I believe, because it presupposed that there would be inappreciable diffusion of motion. I am, however, inclined to think that, if a liquid become turbulent by drawing out and twisting together long thin vortices, the rate of translation of the vortex cores would ultimately become very slow, and that the consequent diffusion of motion would become slower and slower as time went on, and the tur- bulence become more and more fine-grained. This result follows from the continual drawing out of the vortex filaments by their tangling with one another. In being thus drawn out, their energy of circulation is continually being increased; and as the total energy per unit volume of the fluid must remain constant, it follows that the energy of translation of vortex core would continually diminish. Hence there seems to me every reason to believe that wave disturbance can be propagated within such a turbulent liquid. Subsequently Lord Kelvin showed (Royal Irish Acad. Proe., ser. iI. 1889, vol. i., p. 8340) how to calculate a stable, steady motion for a hollow vortex surrounded by a tore round which the liquid was circulating, and concluded that it would be possible Fitz Gmratp—AHypothesis as to Electro-Magnetic Actions. 51 ‘to fill space with a series of approximately straight hollow vortex filaments which would be in stable steady motion. This seems to finally dispose of the objection that diffusion of vortices must take place, at least in the case of hollow vortices; and by making the vortex filaments sufficiently fine, the space might be filled with full vortices whose rate of diffusion could be made as slow as necessary to explain the ether, even if it could be shown that such an arrange- ment of full vortices would not be stable. What I now desire to call attention to, is a hypothesis as to the nature of the wave motion which can be transmitted by a system of vortex filaments. A vortex filament can have a spiral wave superposed upon it. ‘The irrotational motion in the neighbourhood of this screw will be essentially the same as the distribution of magnetic force near a similar spiral wire carrying an electric current. There will be, on the whole, a flow along the inside of the spiral, but the motion of the fluid is complex. It could, however, be defined by a vec- tor, whose direction was parallel to the axis of the spiral, and whose magnitude was measured by the square root of the mean square of the additional energy per unit length of the moving fluid above that of the undisturbed vortex. If then a space were filled with spiral vortices, all parallel to a given line, and causing flow in the same direction, there would be an increase in the energy per unit volume which could be measured by the square of a vector, say H. There would be, on the whole, a flow of fluid along the axes of these spiral vortices. Now, consider the case of a single spiral vortex surrounded by other parallel straight ones. These latter would not stay straight. ‘They would be bent by the action of their spiral neighbour, and spiral waves would be set up along them. How can we describe this transference of spirality from one vortex to one of its neighbours? It depends upon two vectors—one the vector parallel to the axis of the spiral, and the other a vector perpendicular to the two vortices. ‘The vector then defining the transference, being itself defined by two rectangular vectors, must be a vector perpendicular to both, ¢.e. must, in the ease of a spiral vortex surrounded by others which it is setting in motion, be distributed in circles round the spiral vector. What will the magnitude of this new vector depend on, and how can we define it further? Its magnitude will depend on how fast the K2 52 Scientific Proceedings, Royal Dublin Society. spirality is being lost by the original spiral. If we call this new circularly distributed vector H, and make its magnitude such that its square is equal to mean energy of this new motion, then, assuming wave propagation, we get, on account of the relation of © direction between H and H, and of their velocities being small compared with the irregular motions already existing (so that we can assume them to be superposable linearly), that H must depend linearly on E, thus E=A.VAH where A is a quantity, a velocity depending on the structure of the medium, i.e. depending on the nature of the turbulency in the undisturbed ether. If we now can assume that, in the general case, the energy of the medium is the sum of its energies due to these two vectors, which, so far as they affect one another, are at right angles to one another, then we can write for the energy per unit volume of the ether Oa JB? te Jel, From this, and the principle of conservation of energy, we can conclude that H = -—AVAZ, and from these that SAE=0, and SAH =0, so that, if at any time SAH =0, and SAH =0, they will continue ~ so. Now, these are the fundamental equations of wave propagation in the ether, and it only remains to explain wherein electric charges consist upon this hypothesis. If we consider a point on a spiral vortex, and suppose that the spirality is so arranged that on both sides the flow of fluid within the coils is away from the point, then the spirality on one side of the point must be a right-handed screw, and on the other side a left-handed screw. Now, a point of this kind would be unique in the vortex. It would, so far as the fluid outside the vortex coils was concerned, be a sort of source from which fluid was flowing in all directions. This flow would, at a short dis- tance from the source, be extremely slow, and the action between such points with their vortex spirals would be almost entirely Firz Grratp— Hypothesis as to Electro-Magnetic Actions. 58 confined to the actions already described between the spirals and the accompanying flows within and near them. On this hypo- thesis these vortex spirals would be representatives of the Faraday lines of force. The hypothesis here put forward very tentatively does not include any supposition as to the nature of matter, nor as to how the singular points that represent electric charges, or electrons, can be connected with matter. At the same time it goes some way towards showing that the hypothesis—that the ether is a turbu- lent liquid—has great possibilities underlying it. In explanation of the above, it may be well to state clearly the assumptions underlying it. It is asswmed that the spirality described is propagated unchanged as a wave. This is justified by pointing out that this spirality is essentially the laminar motion investigated by Lord Kelvin, because it involves a flow in the direction of the axis of the spiral, and such a flow cannot take place along the direction of a vortex filament without a spiral deformation of the filament. Lord Kelvin illustrated his theorem by reference to a system of vortex rings which would, however, diffuse among one another in a way that was contrary to one of his fundamental assumptions: while I am citing, as an example of his theorem, the case of infinite approximately straight vortex filaments which he has shown might, certainly if empty, exist in steady motion in presence of one another. It has further been assumed that, initially, SAH=0. This may be justified as follows :—If we assume that, initially, the singular points are points from which a large number of long spirals pro- ceed in various directions, it is evident the same number must enter as leave any surface which does not surround one or more of these singular points, and that the excess of those entering above those leaving, will be a measure of the number of their singular points within the surface. Calling this latter p, per unit volume, we get at once SAH = 4zp, initially. Where p=0, we have SAF = 0, and as SAE =0 at all these points, we see that, even though the original distribution in long spirals rearranges itself among the surrounding vortices, nevertheless SAH will continue to vanish at all these places where there are no singular points. Tt may also be worth while calling attention to the method ot analysis used in this note. I have taken a vector H, to represent o4 Scientific Proceedings, Royal Dublin Society. the various very complex and undescribed movements accompany- ing the spirality described, and the vector H to represent the still less clearly described movements accompanying the propagation of E. This may seem, at first sight, an unsatisfactory method, but it is really quite in accord with our methods of investigation — in other cases. Besides, the obvious case of temperature and entropy which measure properties of bodies whose dynamical character is only very vaguely known, I may take the example of pressure in a gas as very similar. ‘The pressure of a gas was for generations dealt with and most usefully employed long before the structure of a gas was understood. This state of affairs is ‘quite analogous to the condition in which Maxwell left the ether theory of electro-magnetism. He postulated and discovered the properties of electric and magnetic force, without explaining them by any dynamical theory as to the structure of the ether. The analogies he put forward were just as vague and unsatisfactory, but certainly not more so than the gaseous theories that depended on explaining the elasticity of a gas by that of atmospheres of the hypothetical caloric. The kinetic theory of gases explaine their pressure and other properties upon dynamical principles, but when first propounded, and even still, the actual distribution of motion amongst the molecules, atoms, and within the atoms of gases are unknown, but that does not detract from the value of the dynamical theory, nor make us hesitate to use pressure as a function of the state of the gas, although we do not know exactly what that state is. I give these examples of pressure, temperature, and entropy to show that there is nothing abstruse or contrary to precedent in my assumption of H# and H as representing states which are: not, in their entirety, described or analysed. I might have in- stanced directed quantities as examples, such as the stress in a wire subjected to longitudinal pull. This is a very complicated state of stress which can be represented by a single vector, although in no single instance have we any except the very vaguest conception of what the actual state of affairs is inside the wire subject to this stress. el IX. NOTE ON THE RESULTS THAT MAY BE EXPECTED FROM THE PROPOSED MONSTER TELESCOPE OF THE PARIS EXHIBITION OF 1900. By SIR HOWARD GRUBB, F.B.S5., Vice-President, R.D.S. (ABSTRACT.) [Read January 18; Received for Publication Marcu 15; Published Aprit 22, 1899.] Tue Author stated that so many exaggerated reports had appeared lately in the newspapers as to the wonderful results expected from the great refracting telescope proposed for the 1900 Paris Exhibition, that he thought it might interest the Royal Dublin Society to know what might reasonably be expected from such an instrument. According to some papers the Moon is to be brought within four miles of the Earth; while in one account, purporting to be extracted from the Morning Post, this telescope was to be capable of taking photographs of celestial objects on a scale 10,000 times larger than would be possible by any existing telescope. After describing the general features of the proposed Paris telescope, showing how the light-collecting power and magnifying power of telescopes can be estimated, and why it is possible to use high powers with larger apertures &c., the author showed that the light-collecting power of this Paris telescope was only about 50 per cent. greater than that of the 40-inch refractor of the Yerkes Obser- vatory, Chicago, or more strictly speaking, 39 per cent., allowance being made for the light lost by the reflector. In magnifying power, or power of bringing objects apparently closer, it only exceeded the “ Yerkes” instrument by 20 per cent., while in both respects it fell far below the reflecting instrument of Lord Rosse erected more than half a century ago. f 38 X. ON THE CONCENTRATION OF SOAP SOLUTION ON THE SURFACE OF THE LIQUID. By DAVID HENRY HALL, B.A. [COMMUNICATED BY PROFESSOR G. F. FITZ GERALD, F.T.C.D., F.R.S.| [Read Aprit 19, 1899; Published May 8, 1899.] In order to determine whether there is any concentration of soap solution in the superficial film of the liquid, the following experi- ments were made at the suggestion of Professor Fitz Gerald. Lord Rayleigh had observed that the superficial tension of a soap solution while the surface was being extended differs from that of the surface shortly after it has ceased to be extended. He attributed this to a possible concentration of the soapy matter in the superficial film which took place after the surface was formed. He showed that this large superficial tension of a recently- formed surface explained the stability of soap-bubbles and of the foam on frothing liquids. When any part of the surface is thinned out, the tension then becomes great; and, in consequence, the tendency to thin is counteracted, and the film is stable. He analysed the foam of a mountain stream, and found much more organic matter in it than in the rest of the stream-water. This observation is, however, hardly conclusive, and to study the matter further, a soap solution was frothed up, and allowed to drain for a short time, and then the froth was separated from the drained-off liquid, and each separately analysed. The experiments were conducted as follows :— A large stock of saturated soap solution was prepared by allowing distilled water, previously shaken up with pieces of Harti—Ooncentration of Soap Solution on Surface of Liquid. 57 soap, to settle, and then filtered off into a large airtight reservoir of two gallons capacity. A weak solution of standard CaCl, was also made by mixing 10 c.es. of the standard CaCl, solution with 200 ec.cs. of distilled water. A large Winchester bottle, of a couple of gallons capacity, was cleansed thoroughly, and about two quarts of the soap solution introduced, and shaken up vigorously until the rest of the bottle was full of froth. The bottle was then put aside to allow the small bubbles to rise, and then the solution was filtered from the froth, and the froth allowed to settle in the bottle, which was corked tightly to prevent oxidation. The solution poured off was now titrated with the CaCl, from a burette by the usual method for determining the strength of soap solution. The condensed froth was likewise titrated, and the following results obtained :— First EXPERIMENT. SECOND EXPERIMENT. 25 oeumitneut 25 c.cs. condensed 25 €.€S. solution. 25 eves scoucensed c.cs. CaCl. c.cs. CaCl,. c.cs. CaCl,. c.cs. CaCly. 6°65 7:2 6 6-2 6-4 7:3 5-4 6-1 6°65 73 5:2 6°25 6-7 6 6-3 a7 6-2 a) 5:8 Mean, 6-6 Mean, 7:26 Mean, 5°65 Mean, 6°21 The third experiment was made, and a large amount of froth, from a couple of gallons of solution left to settle all night in a closed vessel. On titrating next day it was found to be of less strength than the solution from which it had been filtered, and which had been titrated at time of filtration. Evidently this was due to oxidation, and so another experiment was made, the filtered 58 Scientific Proceedings of the Royal Dublin Society. solution being titrated, also part of the condensed froth, the rest: of the froth allowed to settle all night. Filtered Solution, Condensed froth at Froth titrated next Filtered solution titra- 25 C.CS. same time. ay. ted next day. c.cs. CaCl,. c.cs. CaCl,. clesuCaGle. c.cs. CaCl,. 5°6 6°2 5:4 5°5 5:5 6°25 5°3 5°3 5°45 6.3 5°3 . 0°35 5°5 5°4 Mean, 5°5 Mean, 6°25 Mean, 5:3 Mean, 5°38 To avoid, as far as possible, oxidation, and yet still further to increase the difference between the solution and its froth, as regards the amount of soap in each, the following plan was followed out :— Three Winchester bottles were now used, and the froth frac- tionated twice, the amount of condensed froth not allowing of further fractionation. The filtered solution was also fractionated, the froth thrown away, and the filtered solution fractionated ten times. It is. represented diagrammatically as follows :— Soap Solution D ! 2 3 4 ee Hati— Concentration of Soap Solution on Surface of Liquid. 59 Di and F; were titrated and compared. F';, 10 c.cs. | Dj, 25 ¢.cs. | c.cs. CaCl. c.cs. CaCly. 2 3°9 1°8 3°8 19 3°85 3°8 Mean, 1:9 Mean, 3°83 .°. 19 for 100 c.es. F3. | .°. 15°32 for 100c¢.cs. Dio.| Hence 3°68 mean difference. Again, take F, and D,,, as oxidation has most effect on the froth :— F,, 50 c.cs. D2, 100 C.cs. c.cs. CaCl,. c.cs. CaCl,. har 11°8 79 12-2 8 12 a8 Mer Mean, 7°85 Mean, 12:°025 .. 3°7 c.cs. difference in 100 e.cs. of each. 15-7 for 100 F}. Hence it appears that the froth of a soap solution contains more soap than the solution from which it has been obtained. Several experiments were necessary to get the best working strength of the CaCl, solution, and that of 10 c.cs. CaCl, standard solution in 700 c. es. distilled water was found best. The original soap solution must not be supersaturated, and this source of error was avoided. It appears, therefore, from the experiments, that the soapy matter is concentrated into the superficial layers in accordance with the suggestion of Lord Rayleigh. [ 60 | XI. THE RIO DEL FUERTE OF WESTERN MEXICO, AND ITS TRIBUTARIES. By KINSLEY DRYDEN DOYLE, M.A., Assoc. M. Inst. C.H. (Pxates VI.-XV.) [COMMUNICATED BY PROFESSOR J. JOLY, F.R.S.| [Read Arrit 19; Received for Publication May 30; Published Avcusr 31, 1899.] ‘Tue Fuerte river is a powerful stream, named from its torrential character, draining a basin of 17,000 square miles, including that part of Western Mexico called the Sierra Tarahumare, and falling into the Californian Gulf just south of the 26th parallel of north latitude. (See map, Pl. XV.) The rainfall of this region is a mean between the extreme aridity of the Colorado desert and the tropical copiousness of Tepic and Jalisco; there is a long dry season from November to June, broken only by a few thunder- showers, during which the vegetation is mostly leafless; and the only green objects in the low country are numerous varieties of cactus, agaves, and a few other kinds of plants whose bark serves the purposes of leaves, except in places where the roots can reach water. The prolonged drought dries up all the rivulets in the low land or “tierra caliente” as it is called locally, but the immense rock masses of the plateau—rightly named Sierra Madre, mother of mountains—store up and give out a perennial stream, never falling below 64,000 cubic feet per minute. The Fuerte is 275 miles long from source to mouth, and the united river for a third of the whole length flows through the low plain ; the remaining part and all the chief tributaries pass through rugged foot hills and in deep canons worn in the Sierra itself. This country was traversed by the author in 1897 from west to east, but it will be more convenient for the purpose of description to start near the watershed. Proceeding therefore from the town of Chihuahua on the Mexican Central Railway, one traverses the central plain, gra- dually rising from east to west towards the wave crest of the great slope ; for the first 70 miles the road or track goes over a rugged Doyitr—Rio del Fuerte of W. Mexico, and its Tributaries. 6} country composed of weathered dark volcanic rocks, and studded with abrupt hills which rise like islands in a stormy sea of lava. There is little surface soil, and, except in a few shallow valleys like that of Sta Isavel, the region, owing to drought, is a desert. After reaching Cusihuiriachic, a town depending on very ancient and rich silver and lead mines, the llanos are seen stretching upward toward the watershed of the continent; they are very smooth, broken by few arroyos, and covered with grass forming a good cattle country wherever water is obtainable. Thirty miles to the N.W. of the town is a group of rocky hills whence streams flow in three directions—south-east to the Rio Conchos, which joins the Rio Grande del Norte, and discharges into the Gulf of Mexico —north to the Rio de Sta Maria, an inland system of drainage ending in a salt lagoon near the United States frontier—and west through the mountains to the Gulf of California. The anos preserve the original slope and surface of the old lava flows, and are protected from denudation by their lofty ele- vation, the small rainfall on the inland side of the mountains, and by a coating of soil with permanent grass.!. Travelling over them, is a pleasing contrast to progress over the stony plain, and the antique-looking, leather-slung coaches drawn by teams of eight or ten, well-matched, closely-clipped, white mules go at a fast canter over the smooth surface. ‘Towards the summit of the slope rounded hills studded with dwarf oaks appear, and the ground is broken ; but some attempt at grading the tracks enables wheeled vehicles to go as far as Bocoyna on the head waters of the Rio Conchos, where there is a small settlement of Mexicans and Indians. From this place onwards one must travel mounted or on foot. The highest part of the range in this neighbourhood is Rumerachic, a rounded mountain about 9700 feet above the sea. Here we enter on the pine-clad mesa, which extends, uniform and monotonous, in a belt 50 miles wide, along the crest of the Sierra; except in a narrow central ridge, the general surface is quite level, and covered by a sparse forest of small pines, with very little other vegetable life. Mammals and insects are alike unseen, and the only winged creatures are an occasional flock of ‘ blue birds ” or a stray woodpecker. There being no streams during the 1There are also alluvial deposits in this region, containing bone remains of Quaternary age. ‘62 Scientific Proceedings, Royal Dublin Society. dry season to make the murmuring accompaniment one always hears in the Alps, and as no breath of wind disturbs the constant calm of the air, there is an absolute silence in the forest which is very impressive ; even the footfalls of one’s own mules are deadened by the carpet of pine-needles. These mesas are composed of almost level sheets of light- coloured trachyte, and beds of white friable voleanic ash, with local layers of white pumice ; incrustations of red and white chalcedony, and crystals of celestine are also commonly seen. The commencement of the arroyos which feed the Fuerte river is usually a basin-like space of bare stone completely denuded of all soil, and without vegetation; the sides are steep, and the hollows soon plunge down to the depths of the great cafions; they remind one of the streams on the peat-covered Irish hills, Kippure for example, where a furrow in the living fibrous covering of heather and other plants, soon widens into a gully in the soft peat. Though the scale of the phenomena is very different, yet the forest on the mesa seems to play the part of the heather on the peat, and prevent denudation of the underlying material. In the basins and valleys there are often rounded bosses, and sometimes high pillars left standing in isolated positions, or in groups; they appear to be produced by the protection afforded by hard, resistant patches in the trachyte ; but, unlike ordinary earth pillars, do not develop into symmetrical conical forms; being always twisted into strange and odd shapes, and sometimes overhanging consi- derably ; some are more than 100 feet high. Besides the summer rains, which are not heavy at elevations of seven or eight thousand feet, there is a winter snowfall of about two feet, and the greater part of this, probably finds its way through the surface soil, and, by subterranean passages of the fissured rocks, to the water-level at the bottom of the gorges; for in early summer the small streams are quite dry, though there is plenty of water far down in the gorges. The most striking feature of the mesa on the way from Bocoyna is the great Barranca of the Urique river; one approaches it through level forest to the very edge of the chasm, where it bends suddenly from H.N.E. to8.8.W. The sides are a series of vertical preci- pices, formed by the edges of the different lava flows, connected by steep slopes of detritus covered with vegetation suited to the eleva- tion; for the descent to the stream being 4500 feet, bananas, Doyvtu—Rio del Fuerte of W. Mexico, and its Tributaries. 68 oranges, and cacti will grow at the bottom wherever there is room for them, while there is frost nearly every night on the top; and yet a stone dropped from the edge of the mesa would, in many places, fall and roll all the way to the river. Further up, the cafion contracts to a chasm so narrow that it could be bridged at the top, but here it is a couple of miles wide. Here and there in this region one comes across cave-dwellings of Tarahumari Indians, a primitive race of fine physique; they are of a dark copper red colour, with long coarse black hair reaching to the shoulder, and confined by a fillet round the forehead. They are very shy and retiring, living by their own tribal customs, and making their own pottery, clothing, and arms, without intercourse with white men. As they are not a warlike race, their continued existence and individuality is due to the extreme inaccessibility and poverty of the country; but in power of enduring cold and fatigue, and performing very long marches with no provision but a little parched corn, few hill tribes could compete with them. After passing the Cerro de Coroibo the track visits some large caves on a high part of the mesa where water can always be found; else- where the sources are so far apart that it is desirable to have a guide with local knowledge, to avoid the discomfort of a waterless camp; forage is also so scarce that corn must be carried for the mules. There is a numerous group of grotesque rock-pillars near this place. The ground here commences to‘slope down with a more broken hilly surface towards the téerras templadas, at an elevation of 5000 to 6000 feet ; the tongues of table-land reaching out between river valleys are called cordons, and their level tops enjoy a delightful and invigorating climate ; temperate crops and fruits do well here, and the little towns were gay with peach blossoms in March. Leaving Temoris, a place on the right side of the Septentrion river, we descend to a small ranche at the bottom of the valley, where an artificial water-course irrigates some terraces planted with oranges; there is hardly any level ground, for the steep sides of the V-shaped valley nearly everywhere sweep directly into the stream. Here, mineral veins, which are uncommon in the upper trachyte beds, begin to appear, and there is a large mine close by at Realito. Now, ascending to the crest of the left bank at Pan- dura, the first view of the foot hills is obtained ; they lie extended 64 Scientific Proceedings, Royal Dublin Society. like a map beneath the giants of the mesa; and were it not for their steep and intricate forms, the windings of the river valleys could be easily traced through the transparent atmosphere. The clearness of the air in these regions is remarkable, even for the Pacific coast ; the stars at night shine with astonishing brillianey > and a lofty mountain of striking form, the Cerro de Alamos, is. visible all day at distances over 60 miles, where nothing inter- venes, except in the rainy season. To the south-east of Pandura is the peak of Metate standing on a spur of the mesa, isolated by the erosion of two streams, and surrounded on three sides by im-. mense vertical precipices. There is a wide difference between the shapes of mountains in this latitude, and the ice-planed forms of Europe; as long as the rivers can deepen their beds they do not widen the valleys at all, which remain either cations enclosed by cliffs, or V-shaped cuttings, usually terminating at the bottom in a narrow gorge. On the lower ridges the evergreen flora is more varied and abundant ; three varieties of oak, three of pine, and one of arbutus are common; the arbutus, with its thick stem, bright orange red bark, dark green leaves, and white flowers, is very pic- turesque; and the Hnsia roble,an evergreen oak, with thick leathery leaves, is very distinct. Lower down, below 5000 feet, agaves, ma- millaria, and prickly pears (Opuntia) are abundant among the grass that covers old geological formations, or under the dwarf forest that flourishes on recent volcanic ejectamenta. Following the ridge towards Guaza, the track overlooks a wide basin, grass-covered and dotted with dwarf oaks, into which two streams converge at an acute angle, leaving between them a thin slice of table-land, stand- ing up perpendicularly 3000 feet above the stream, and revealing its structure of horizontal beds; the upper pale acid lava, and the lower of dark basic materials. Such wedges are common at the margin of the mesa, and are sometimes isolated into towers that eventually crumble into conical forms; when first isolated, they are locally called caballos (horses); the ridges produced by erosion often terminate in a diminishing row of peaks that have been formed in this way. This flamboyant style of mountain sculp- ture shows that no severe earthquakes have affected this part of Mexico for a long time, as many of the grotesque rock-pillars and lofty partition walls have such slender bases that a violent shock would certainly overturn them. Doyie—Rio del Fuerte of W. Mewico, and its Tributaries. 65 At Guaza the Chinipas and Septentrion rivers join, and there is a little level ground laid down by the rivers during a temporary obstruction of the lower gorge, caused by recent volcanic eruptions, to be further noticed. Between Guaza and La Junta, where the main river forms, the valley has been eroded to the base of the volcanic series, exposing syenite; a calcareous fossil was also ob- served in the shingle, though time did not allow a search for its parent stratum. Turning now east, up the main branch of the Fuerte river, we have before us a portion of country about 40 miles long and 20 miles wide occupied by the wasted voleanoes of a secondary eruption ; all the rocks here are dark basic lavas, and some of the flows can be seen little altered, still forming the surface of the ground, or filling former river valleys. Mineral veins are abun- dant in a belt reaching from San José de Gracia near the boundary of Durango, to Rosario mountain, near that of Sonora, especially at the junction of the dyke-intersected syenite, with the volcanic rocks. Gold occurs frequently, associated with silver and copper as sulphides, and sometimes in veins of iron ore. As the river runs in a chasm, the practicable track crosses the shoulder of the Cerro de Volean—a prominent peak among the foothills; its top is evidently the hard core of a crater, and its sides the eroded materials of the cone; denudation is proceeding apace among these small mountains from the action of the heavy autumn rainfall on their loose layers; nearly all the ground stands at the angle of friction, everything is just ready to roll; and the tops of the ridges and bottoms of ravines are quite narrow. Near Volcan there are four or five other extinct cones in the same stage of decay. Descending to the bed of the river at San Francisco, one finds it rocky, and with a rapid fall ; numerous waterworn boulders as large as 10 feet in diameter are piled along the margin, attesting the force of the stream when swollen 50 or 60 feet above its dry season level. Above Realito it has cut through a thick homogeneous layer of reddish rock, very free from fissures, and has left perpen- dicular cliffs nearly a thousand feet high; on emerging from this pass, one stands ona lake terrace over the river ; observation of the surrounding hills discloses other parallel terraces at different higher levels. The wide valley is covered by regularly bedded lake deposits through which the river winds in sinuous curves, cutting SCIEN. PROC. R.D.S8., VOL. IX., PART I. F 66 Scientific Proceedings, Royal Dublin Society. cliffs from 40 to 70 feet high. Against the sky is the vast wall of the distant mesa, indented with square notches, like the machico- lated parapet of a castle, by the straight-sided ravines. The bed of the ancient lake is 1000 feet above sea-level at its lowest point, and consists of white and bright green. sandstones and conglomerates in thin but continuous layers. During the dry season the river bed is a convenient road, though it necessitates frequent fording, as the stream meanders from side to side. The sandstones were examined for fossils, but none were found. After nine miles of gently-sloping, walled-in course, a place is reached where the lake beds have been cleared away nearly down to the present river level: probably by wanderings in the course of the current: and on this plain is the small town of T'ubares. The ancient lake and its fluctuations of level must have been caused by volcanic eruptions in the previous river valley damming the channel up with lava and ash; and when largest, the lake covered 100 square miles, to a maximum depth of at least 1000 feet ; the thickness of the lacustrine strata below the present river level could not be ascertained without boring. Should it ever be desired to regulate the flow of the Fuerte river, either for water-power or for extended irrigation in the low country, it could be done efficiently at a moderate cost, by con- structing a dam at the gorge of Realito, where there is a narrow passage, solid rock for foundation, and a long gentle slope for the reservoir. Above Tubares, low cliffs close in again on the river ; here they are of a compact white stone, in appearance like limestone, but probably derived from the waste of the acid lavas ; then the valley opens again as the junction with the Urique river is reached, the left branch being the product of the main stream from Hl Zapori and the Batopilas river. Long ages elapsed between the eruptions that built up the mesa, and those which formed the Realito group of foot-hills; for during that interval, the Urique and other rivers eroded valleys more than 5000 feet deep, and extended the littoral plain at the expense of the plateau. After the new volcanoes had covered the plain, the rivers deposited the lacustrine beds of Tubares, and cut a deep channel through the erupted material. Doyvte—Sfio del Fuerte of W. Mexico, and its Tributaries. 67 All the foothills are covered with a low forest of thorny trees and shrubs, leafless in March, but not without blossoms, the “ palo blanco” in particular being covered with corymbs of large, white, sweet-scented flowers, the food of parrots and deer, and the haunt of humming-birds. . a | laa 22 3522-49 (CN)>. | = 3498-5 3497-7 (ON)2. = 3487-8 3487-61 (CN). Ee In conclusion, it may be admitted that a spectrum obtained with a prism of small dispersion is not the same as that photo- graphed with a grating of very great dispersion, though both may have their origin in the same flame. ‘The greatest differences between the two will appear at the less refrangible end, where the bands shown by the prism are resolved into groups of lines by the grating. It is therefore better to compare the numbers obtained by Eder and Valenta with small dispersion with my 296 Scientific Proceedings, Royal Dublin Society. quartz prism photographs obtained in a similar manner; and it will be noticed that the difference between them is not very remarkable, particularly in the violet and ultra-violet. That these photographs contain a greater number of lines than those of Eder and Valenta may be accounted for—first, by the difference in the flame employed and the part of it examined ; secondly, by the composition of the gas not being exactly the same. It has been observed by Lecocq de Boisbaudran (and this has been mentioned in my original paper) that even a Bunsen burner may offer, under slightly different conditions, spectra which materially differ. With compressed oxygen used in a blow-pipe with a large flame such differences may be greatly increased, and this is believed to have been the case in consideration of the fact that a whole group of lines, not recorded by Eder and Valenta, are in close agreement with a group peculiar to the spectrum, which I have since recognised as belonging to cyanogen. Eder and Valenta examined the inner cone of a Bunsen burner, fed with oxygen at 3 to 2 of an atmosphere pressure, with an instrument of small dispersion, and also with a grating of 15 feet radius. I studied the upper half of a gas blow-pipe flame sup- plied with oxygen under a pressure of as much as 22 atmospheres, using merely a quartz prism, and by such means only could the purpose of the investigation have been satisfactorily fulfilled. There is, however, one further remark to be made, namely, not only was the method of burning the gas different to that employed by Eder and Valenta, but the composition of the gas itself may have been very different. If, for instance, the gas contained cyanogen or cyanides it would certainly yield the cyanogen lines or bands upon combustion, for very minute traces suffice to produce some part of that spectrum. I entertained no doubt whatever that the cyanogen bands entered into the spectrum of the oxy-coal-gas flame examined by me. Moreover I have proved the existence of cyanogen compounds in the gas in quite sufficient quantity to account for it in the flame. The supply pipe of an ordinary Bunsen burner was made to deliver gas at the rate of five cubic feet per hour, and for a period of one hour, into a series of bulbs containing a solution of ferrous sulphate, made strongly alkaline with caustic potash solution. Hartiey— Occurrence of Cyanogen Compounds in Coal-Gas. 297 On examining the liquid it was found to possess a strongly ammoniacal odour. On the addition of a few drops of ferric chloride and acidifying the mixture with dilute hydrochloric acid, there was a voluminous precipitate of Prussian blue, sufficient to make some 15 c.c. of liquid thick with the solid substance. This completely sets at rest the question of the possibility of the lines being due to cyanogen. Irrespective of this evidence it should be mentioned that a very peculiar yellow and yellowish- green colour tinged the oxy-coal-gas flame in a,manner similar to the coloration which may be observed like a halo on the edges of the mantle of the peach-blossom coloured flame of cyanogen. This at the time seemed to be probably due to the synthesis of cyanogen or of hydrocyanic acid by the action of intensely heated hydro- carbons in contact with nitrogen. It should be stated that, in testing the coal-gas, an alkaline solution without the addition of ferrous sulphate did not absorb so much of the cyanogen compound, and that plain water gave merely a very distinct Prussian blue colour. From this it would appear that the substance is either ammonium cyanide or some other cyanogen compound that splits up into ammonia and hydrocyanic acid. It is of no little interest that the presence of cyanogen com- pounds in the gas supply of a large city like Dublin should first have been indicated by the bands and lines observed in the spectrum photographed from the flame of the burning gas. [ 298] XX. THEORY OF THE ORDER OF FORMATION OF SILICATES IN IGNEOUS ROCKS. By J. JOLY, D.Sc., F.R.S., Hon. Sec. R.D.S., Professor of Geology and Mineralogy, Trinity College, Dublin. [Read MArcu 21; Received for Publication Marcu 23 ; Published May 12, 1900.] Ir is well known to petrologists that the order of solidification of the silicates of igneous rocks is not that of their melting points; and the fact has been stated generally by Prof. H. Rosenbusch that this order is that of decreasing basicity. That is to say, the minerals successively formed contain ever increasing quantities of the acidic constituent, silica. Thus (1) ores, (2) ferro-magnesian minerals, (3) felspathic minerals, (4) quartz, is the order of solidification. Within these groups the rule is also followed: thus, in the second group, olivine precedes biotite, and biotite precedes pyroxene. In the third group, the less acidic triclinic felspars precede the monoclinic. Again, in porphyritic rocks, in which interruption due to physical causes in the slow process of segregation has occurred, the minerals of the second consolidation obey the same general rule. To the general rule there are exceptions—or apparent excep- tions. Thus, some of the minerals of the second and third groups may appear in inverted order in the dolerites and gabbros. Again, in pegmatitic and ophitic structures, simultaneous crystal- lization of quartz and felspar, or of pyroxene and felspar, may occur. When it is remembered that rock formation was often carried on under conditions sufficient to magnify the importance of the volume relations of the constituents, and under conditions of quiescence favouring super-cooling, the fact that other than the intrinsic chemical and physical properties did not always govern the result, is not to be wondered at. ‘The object of this note has, however, reference to the rule, not to the exceptions. J oLy— The Order of Formation of Silicates in Igneous Rocks. 299 I have lately found that the softening point of quartz is far below what is currently thought. My experiments on this point were carried out in the following manner :— A. quartz fibre was stretched horizontally, fixed at one end, and at the other a tensile force was applied. This was produced by causing the fibre to displace from the vertical a pendulum carrying a small mass as its bob. For 10 cms. of its length, this fibre traversed an open trough of platinum foil—square in section and 0-10 x 0-15 cms. in dimensions. This trough, being arranged so that it replaced the ribbon of a meldometer, could be heated to any required degree by a current, and its temperature determined by its thermal expansion. The fibre was so placed in the trough as to be depressed somewhat below the axis or central line of the latter. Two micrometer microscopes observed points on the fibre (obtained by wetting a short length of it with varnish and dusting charcoal powder upon it) placed well to right and left of the heated portion. The displacement of the point on the cross wires of the right-hand micrometer measured the extension; the micrometer to the left of the trough served merely to safeguard against unnoticed displacement occurring at the fixed extremity of the fibre. The data are :— Force, . : : 0°425 grams. Length heated, . 10 cms. Diameter of fibre, . 0:00136 ems. Cross-section of fibre, 0°145 x 10° cms. Stress, : . 293 x 10° kilogrames per sqr. cm. Temp. of trough, . 850° C. Under these conditions one set of observations gave— In 55 minutes extension = 0:076 cms. In next 35 ,, ae = 0089 5, Many other observations were made at this temperature. The extension continually progressed: finally the fibre broke when cooling the trough. I may observe here that the stress applied is about 5th the minimum carrying power of quartz fibre. 300 Scientific Proceedings, Royal Dublin Socicty. The quartz here is obviously at a temperature considerably below that of the walls of the trough, seeing that this latter is open freely to radiation and convective cooling. Further experiments, using a platinum tube and stronger fibres, appeared to reveal slow extension at still lower tempera- tures, but the completion of these I have had to defer. Previous results have always placed the softening point of quartz at a much higher temperature ; the apparent melting point is, in fact, higher. Not till temperatures of between 1400° and 1500° ©. are reached does fine quartz dust show any change appreciable in the time we ordinarily assign to observations of the kind. Mr. Ralph Cusack, working with a meldometer, gives its softening point at 1406° C. (“ On the Melting Points of Minerals,” Proc. Royal Irish Academy, 3rd ser., vol. iv., p. 399), and in my own previous observations I had fixed its softening point as only a little over 1400° C. (see Plate VI., “On the Determination of the Melting Points of Minerals,” Proc. Royal Irish Academy, 3rd ser., vol. ii., p. 38). Previously to these observations, it had been fixed as very much higher—above the melting point of platinum by some—that is, over 1750° C. Evidently the observations indicate that silica is a body possessing an extraordinary range of viscosity. It is a thick—a very thick—liquid at about 1500°C. At a temperature of about 800° C. it is plastic, and yields with considerable rapidity to distorting forces. We may, perhaps, infer from the complete absence of cleavage that it is a substance which never crystallizes very vigorously. Let us now see if the oxides, entering as bases into the constitution of the silicate, possess similar properties. These are chiefly—alumina, lime, magnesia, soda, potash, and iron- oxides. Alumina.—According to M. Moissan (“Le Four Electrique,” Paris, 1897), when melted and again cooled, this substance rapidly crystallizes. The crystallization of small rubies (coloured with a little sesqui-oxide of chromium) is so rapid that 10 to15 minutes suffices for their formation. Crystals may also be obtained by sublimation. This, then, is evidently a body of very different properties from silica. It is a rapid and vigorous crystallizer from the state of fusion. Joty—The Order of Formation of Silicates in Igneous Rocks. 301 Calcium Oxide.—This can be crystallized by sublimation in the oxy-hydrogen flame, covering the lime cylinders with a thin trans- parent film and brilliant crystals (Proc. Royal Dublin Society, vol. vi., p. 225). M. Moissan reports that it cools from liquidity to a crystallized solid. It possesses a very high melting point, which is lowered by addition of Al,Os. Magnesium Oxide.—Much like calcium oxide, but with a higher melting point: gives in the electric furnace large, transparent erystals out of the liquid, often several millimetres in length. Sesqui-oxide of Iron.—F uses rapidly, losing some oxygen, and pasing into the ferroso-ferric oxide, Fe;O,, which remains partly erystallized. It combines vigorously with the material of the furnace. Potassium Oxide and Sodium Oxide.—These are known to become liquids at a full-red heat. Further information I have not obtained. Now, if we assume that the properties of the first three of these bodies are in any marked degree additive, there is evidently a full explanation of the apparent abnormality in the order of erystallization of many silicates. ‘The silica enters as an influence retarding crystallization and prolonging the viscous properties downwards in the scale of temperature. CaO, MgO, A1,O;, on the other hand, are ecrystallizers at high temperature, and influence the molecule accordingly. That some such additive result is to be expected follows, perhaps, from the nature of the silicates, which, as Prof. Mendelieff observes, partake greatly of the nature of alloys.’ He adduces the fact in support of this, that their specific volumes are additive. Thus, the volume of the silicate orthoclase can be closely calculated from the volumes of the constituents—A1,O;, K.O, 6SiO,; and also the fact that the chemical union of these oxides is feeble, water, H,CO;, and such weak agencies, being able to gradually break them up.’ ‘The properties of glasses, too, are in many 1 It is noteworthy, in this connexion, that the solidifying points of alloys are only exceptionally below or above those of the constituents. These exceptions are well- known. Such curves as Gautier’s, while showing that rarely is the solidifying point influenced directly proportionately to the percentages of ingredients, reveal that the introduction and increase of a constituent of high melting point involves, in general, a rise in solidifying point. 2 « Principles of Chemistry.’’ London § New York, vol. u., p. 118. 302 Scientific Proceedings, Royal Dublin Society. particulars additive. In solutions of electrolytes, which may, perhaps, be looked upon as chemically similar to glasses, viscous properties, and many others, are additive.’ According to the theory I advocate here, the silicate, A, con- taining a small quantity of silica, crystallizes out at a higher temperature than the silicate, B, containing a larger percentage of silica, because the crystallizing point of A is less affected by the silica than in the case of B. A test of the melting point under ordinary conditions may not reveal this, for the rigidity of B, due to its greater amount of silica, may confer apparent solidity upon it at a temperature at which A has yielded to gravitational and surface tension forces. ‘This will be understood from the diagram below. Fluidity Temperature 800° 2 1187° 14.00° Here, at the level, 4 7, the fluidity has attained to such a degree as to cause yielding to gravitational distortion. This occurs at a lower temperature for the augite than for the quartz. According to the hypothesis now put forward, approaching the 1 The elaborate work ‘‘ On the Relations between the Viscosity (Internal Friction) of Liquids and their Chemical Nature,’’ by Messrs. Thorpe and Rodger (Phil. Trans., vol. 185 A, p. 397, and vol. 189, p. 71), applies to very definite chemical compounds, but even in these cases many interesting regularities are described by the authors. See Whetham’s ‘‘ Solution and Electrolysis’? (Cambridge, 1895), chap. xz. Joty— The Order of Formation of Silicates in Igneous Rocks. 303 base-line, we should find that the quartz has retained some fluidity below the temperature at which the augite is solid. In so far as this diagram is hypothetical, it derives support from the observed more rapid liquefaction of the more basic silicates at high temperatures. The steeper rise of the fluidity curve for augite at high temperatures (that is the part prolonged above f, /) is, in fact, matter of observation. This fact is very probably also shown in the volume-change at these temperatures.' The true melting point, from the present point of view, is only to be obtained by observations on the behaviour of bodies under distorting forces. ‘These observations I am now making, but they will be tedious, and delayed by other work. Unfor- tunately, while the observations of viscous yield will undoubtedly afford valuable data, the possibility of obtaining estimations of the molecular forces concerned in bringing about crystallization, and so completing the test of the theory, is not so apparent, unless we may consider that the resistance to distortional force offered by the crystallized substance involves this quantity. But even should direct observation fail to completely elucidate the question at issue the knowledge of the viscous curves must enter any complete theory of the order of solidification of the silicates. It appears, too, that the experimental means affording these data may be extended to reveal how far hysteresis attending the solidi- fying points may exist, and, if so, whether this is related to the percentage of silica present in the silicate: a line of inquiry at once suggested by the views expressed in this note. * “On the Volume-Change of Rocks and Minerals attending Fusion.” By J. Joly.. Trans. Royal Dublin Society, New Series, vol. vi., p. 283. SCIENT. PROC. R.D.S., VOL. IX., PART III. P Fo [202 J XXI. RECENT ANALYSES OF THE DUBLIN GAS SUPPLY AND OBSERVATIONS THEREON. By J. EMERSON REYNOLDS, M.D., So.D., F.R.S., Professor of Chemistry, Trinity College. [Read Aprin 25; Received for Publication Aprit 27; Published May 12, 1900.] LarcE quantities of the city gas are used for various purposes in Trinity College, and it is the practice to analyse it occasionally in the Chemical Laboratory in order to ascertain whether its quality is maintained. In the course of the series of analyses made during the last five months, in conjunction with my excellent Assistant Mr. E. A. Werner, F.1.C., I detected a marked change in com- position which began in February and continues to the present time. This change indicated that plain coal-gas was no longer supplied, but that a mixture which includes a considerable propor- tion of ‘‘water-gas”’ has since been delivered. On the 12th of last March I drew attention to this change in the course of a lecture delivered in College on that date. Extracts from that lecture appeared in the daily papers and led to considerable discussion, in the course of which opinions were attributed to me as to the probable effects of the change which I did not express and cannot be in any way responsible for. I therefore desire in this paper to place on record the analyses made, and to shortly state the related considerations which should influence opinion as to possible danger attending the public use of mixtures of coal and water-gas. Twelve analyses of the Dublin gas supply performed between the 25th of November, 1899, and the 16th of February, 1900, gave the following mean results, which agree with those of average Rurynotps—Recent Analyses of the Dublin Gas Supply. 305 coal-gas, and supply a fair standard of composition by means of which any variations can be recognised :— Mean results of twelve Analyses made Constituents in 100 volumes. between November 25th, 1899, and February 16th, 1900. Carbon dioxide, . : é s 2°5 Carbon monoxide, : : : 6-2 Oxygen, . : é ‘ : 07 Illuminating hydrocarbons, . : 4:3 Non-illuminating hydrocarbons, . | 86:3 | 100-0 The results of a series of analyses of the Dublin supply performed since the 16th of February, 1900, are given in the table at end of this Paper (see p. 313). Apart from minor variations, to which I shall not further refer, the significant difference in this series is the increase in the per- centage of carbon monoxide found in the specimens examined. The first series of analyses proves that the ordinary coal-gas supply to Dublin during nearly three months contained on the average 6°2 per cent. of carbon monoxide. ‘The second series shows that there has been a gradual rise in the proportion of carbon monoxide until it had doubled on the 7th of March, and, two days later, the percentage had nearly trebled at 17:9: it then fellaway, and subsequently rose again to 13-9 per cent. on the 20th March, and reached 15-6 per cent. on the 24th of April.1 So great a change could, practically, only be due to the addition of water-gas. As soon as the trend of the results became clear, I communicated with the Gas Company (on March 6th), and they admitted that a pro- portion of carburetted water-gas had been mixed with the coal-gas. 1 No analyses were made between March 21st and April 24th. Z2 306 Scientific Proceedings, Royal Dublin Society. Members of the Society are well aware that what is technically known as “ water-gas”’ is produced by passing steam over red-hot coke when the following change is realised :— H,O + C =CO+ H.,. That is to say, the carbon in the form of coke, when sufficiently heated, removes the oxygen from water vapour, and produces there- with carbon monoxide gas, while hydrogen is also set free. The mixture of combustible gases so obtained gives a very slightly luminous flame and has little odour. When petroleum or other oils are vaporised at a sufficiently high temperature in this gas, their products render the flame much more luminous and com- municate a strong odour. The product is “ carburetted water-gas,”’ and contains about 30 per cent. of carbon monoxide, the rest consisting of hydrogen and small proportions of its carbides. This gas is much cheaper than coal-gas ; it is more readily and quickly manufactured, and its production enables a gas company to use up a considerable proportion of its coke to advantage. Moreover, it can be easily made of almost any desired illuminating power, and is not more explosive with air than plain coal-gas. It is therefore much to the interest of a gas company to mix a considerable proportion of this water-gas in their supply, and such mixtures have been used in the United States since 1878, and to a much smaller extent in these countries since 1891. Some American cities such as Boston, New York, and Chicago now use almost unmixed water-gas; but in the United Kingdom compara- tively few towns as yet use a mixture, and in those which do, 50 per cent. of water-gas is seldom added. In London very little has hitherto been used, and several companies are said not to have distributed any. There does not seem to be any statutory difficulty in the way of the companies substituting water-gas for coal-gas, and there would not be any general objection to their doing so wholly, provided there was no greater risk to health and life than with ordinary coal-gas. But that such danger does exist is beyond question, as carbon monoxide gas is a powerful and direct poison. A gaseous mixture which contains much of it, as Dublin gas now does, is necessarily more poisonous than the ordinary coal-gas which seldom included more than 6 per cent. Therefore, in the lecture already referred to, I said just so much by way of warning, Reynotps—Recent Analyses of the Dublin Gas Supply. 307 but was careful to add:—‘I do not want you to suppose that there is any ground for undue alarm, or that the addition of water-gas to coal-gas is not legitimate; I think, however, that the fact of so material a change in the nature of the supply should have been notified to all consumers, in order that they might be on their guard against escape of the new gas from any causes.” I do not think it would be possible to draw attention to a serious matter of the kind in milder terms than these, and no other statement was made by me. Nevertheless, at a recent general meeting of the Dublin Alliance Gas Company, the Managing . Director is reported in the newspapers to have said that the ques- tion was brought forward in order to create a “ scare,” although I had specially deprecated anything of the kind. It is therefore desirable to support the reasonable warning I gave, as to the risk which attends the use of the mixed gas, by references which I did not consider necessary in the first instance. In doing this, I shall set aside, as far as possible, any merely personal opinions, and only state fairly those of a tribunal of undoubted authority, expressed in a public document, after careful examination of all the points which could be brought forward by all interested persons. The document I refer to is an important Report of a strong Departmental Committee appointed by the Home Office, which was issued last year, on the “ Manufacture and use of Water-Gas and other gases containing large proportions of Carbonic Oxide.”? This Committee examined a large number of gas managers as well as medical and other experts, and after taking evidence, which was obtained from America as well as the United Kingdom, requested a distinguished member of the Committee, J.S. Haldane, M.D., F.R.S., to draw up a digest of the evidence affecting the poisonous action of carbon monoxide mixtures, and to make indepen- dent experiments in order to clear up some doubtful points. This important digest forms the chief of the several Appendices to the Report of the Committee, and they state that ‘“ The results arrived at represent the grounds upon which much of this Report has been 1 Carbonic oxide is the name commonly given to carbon monoxide; but the latter is generally preferable in order to distinguish this gas from the familiar carbon dioxide, or ‘‘ carbonic acid’’ gas. 308 Scientific Proceedings, Royal Dublin Society. based ” (see page § of Report of the Committee). Anyone desiring to correctly estimate the value of the conclusions expressed in the general Report should therefore refer to Dr. Haldane’s excellent digest, but it is sufficient for my purpose to cite the statements of the Committee which affect the main question. The Report states (page 8) that “The poisonous action of coal-gas and water-gas is due solely to the carbonic oxide which they contain, that the higher the proportion of carbonic oxide the greater is the poisonous property of the gas, and that given equal conditions as to size of room, flow of gas, length of exposure, &e., the danger to life from an escape of carburetted water-gas or of coal-gas mixed with any considerable proportion of water-gas is far greater than that from an escape of ordinary coal-gas. ‘The danger, in fact, increases at a much greater ratio than the propor- tion of carbonic oxide.” This deliberate statement of conclusions drawn from facts well ascertained by the Committee, disposes once for all of the assertions made by interested persons that the water- gas mixture is not more poisonous than ordinary coal-gas. Carbon monoxide is well known to act as a poison by forming a strong compound with the hemoglobin of the blood, and so preventing that absorption of oxygen from the air which is necessary for the maintenance of life. So strongly is the carbonic oxide held by the blood that it is desirable to resort to inhalation of pure oxygen in cases of partial poisoning by it. According to Dr. Haldane’s report, air containing anything more than 0:2 per cent. or 2 parts per 1000 ought to be regarded as entailing risk to hfe. Half a part per 1000 is still capable of causing, even in healthy persons, giddiness and headache. Dr. Haldane adds (see page 71) :—“ The after-symptoms of carbonic oxide poisoning are often of a very serious nature,’ and then details the various symptoms which I do not think desirable for quotation here. It is only fair to say that there is no real evidence that carbon monoxide is a cumulative poison in the strict sense of the term ; but the statement just mentioned indicates considerable interference with nerve power, and consequent lowering of vitality even long after the poison has disappeared from the organism. It is pro- bable that repeated inhalation of minute quantities—without any real storing in the system—would ultimately lead to similar results. Rrynoips— Recent Analyses of the Dublin Gas Supply. 309 Gas managers and others, interested in the supply companies, have strongly urged that the water-gas mixtures have not caused more accidental or other deaths than plain coal-gas. They laid their case fully before the Committee, but the latter do not adopt their views. On the contrary, the Committee point to the Ameri- can statistics, and quote the case of Boston where there were 29,554 consumers using plain coal-gas in 1886, but no accidents were recorded. In 1890 there were 46,848 consumers of a gas supply of which only 8 per cent. was water-gas, and there were six deaths from gas poisoning. In 1895 the number of consumers reached 68,214, while 90 per cent. of the supply was water-gas, and 24 deaths occurred. In 1897 the consumers numbered 79,893, the gas contained 93 per cent. of water-gas, and there were 45 deaths. After discussing the cases of other towns, the Report goes on to say :—‘‘ After making every other due allowance, we feel that the state of affairs disclosed in Boston, New York, San Francisco, and other towns is decidedly serious. As regards Boston this is the opinion of the Gas and Electric Light Commissioners also.” Dr. Haldane points out that the number of accidents by the use of mixed gas increased approximately as the cube of the gain in percentage of carbon monoxide. Thus, if the percentage of monoxide he increased from 6 to 12, the chances of poisoning were not merely doubled, but were 8 times greater. Similarly, if the percentage rose to 18 per cent. the number of accidents was 27 times greater than at 6 per cent. ‘This rule,” he adds, “‘ would seem to be borne out in the case of Toronto’, and, so far as it is possible to judge from the very partial information available in the case of towns in the United Kingdom distributing any water-gas, experience in this country also points in the same direction.” 1« The total death-rate for poisoning of every kind in this country, whether acci- dental or suicidal, and whether by solids, liquids, or gases, is only about half the average death-rate from water-gas poisoning alone in Boston, New York, San Francisco, and Washington”’ (Digest, page 73). It is, however, desirable to point out that there are high percentages of water-gas in these towns; thus, following the above order, they are 90, 80, 70, and 100 per cents. 2 Where 50 per cent. of water-gas is used, 7.¢. equal volumes of the two gases. It is well to point out that the Dublin gas analysed on March 9th contained nearly as much water-gas, and that on April 24th nearly 40 per cent. It is right to add that on two other occasions only, when analyses were made, did the Dublin gas contain more than 20 per cent. of added water-gas. 310 Scientific Proceedings, Royal Dublin Society. As to the way in which accidents may occur, it is to be noted that the Committee consider that very slight escapes due to doubtful fittings, even at night, do not appear to be rendered more formidable by the introduction of carburetted water-gas ; but, when— “These escapes occur owing to various accidents, such as the unnoticed turning on again of a tap which has been turned off ; the blowing out of the gas-light; the extinguishing of the light by stoppage of the pipes or turning off at the meter, and the renewed flow of the gas without the taps having been turned off. Fatal results have also been traced to breakages or leaks in mains or service pipes, whereby gas has percolated—sometimes being deodorised—through the earth into a house; and to leaks through a wall or through a ceiling or floor from a gas pendant in the room below. In these ways accidents have been caused in houses and rooms to which gas was not laid on”’ (page 7). Although the Committee do not consider that “ very slight ” escapes from imperfect fittings are likely to do material harm, they go on to say (page 9)— “Our attention was called by several witnesses to the very imperfect and unsatisfactory gas-fittings often used in the poorer class of houses in large towns, and the constant leakages which exist without any attempt to discover or rectify them; and it has been suggested that powers might be given to Local Authorities to enable them to enforce a standard of fittings when newly put up in such houses (as is done in the case of water fittings), and also to inspect such fittings when required. We think that such powers might with advantage be given, to be used at the discretion of the Local Authority.” This is an important opinion in view of the general malaise which is known to follow the continued inhalation of air contain- ing small proportions even of ordinary coal gas. In concluding their Report, the Committee place on record their matured opinions in the following words :— “To sum up, we have come to the conclusion that, if the accidents attributable to water-gas are not yet very numerous in Great Britain, the reason is, that the proportion in which this gas (carburetted water-gas) has been used has not hitherto, except in Rrynoitps—Recent Analyses of the Dublin Gas Supply. 311 a few instances, been high. A large increase in the use of the gas is, however, to be expected in several localities, and in some places the use of pure carburetted water-gas is contemplated in the absence of legislative restriction.” ‘We therefore think the present time opportune for dealing with the matter before the manufacture of water-gas is established on a larger scale; and we beg to submit the following recommen- dations, to which, if approved, effect should be given by a Public Bill.” Among these “ recommendations ” are the two following, with which we are directly concerned :— “That before any kind of water-gas is distributed in any place, due public notice of the proposal should be required to be given: and that, as long as there is any water-gas in a gas supply, that fact should be stated on every demand note.” This was precisely the view I took as to the duty of the Alliance Company to consumers, and I rather expected that the Company—especially after I had early notified them of the detection of the water-gas mixture—would have been glad to render any public warning from me unnecessary by stating their view of the matter to their customers, and they had ample time to do so in the interval before my lecture was delivered. It is clear, from the reference to the “demand note,” that every quarterly gas bill should be a renewed notification, as a reminder to consumers that there was need for continued and _ special caution. The other “ recommendation ” referred to is:— “That power should be conferred upon a Central Department to make regulations, enforceable by adequate penalties, limiting the proportion of carbonic oxide in the public gas supply at night to 12 per cent., or such greater amount as the Department may consider desirable,” 7.e., as I understand, such greater amount being permissible in order to meet special emergencies. I have now laid before the Society the chief conclusions arrived at by the Commission which the Home Office charged to inquire and report as to the safety or otherwise of introducing any large proportion of water-gas into city gas supplies. It will be seen from the quotations that my warning of the 12th of March 312 Scientific Proceedings, Royal Dublin Society. rather wnderstated the case against water-gas mixtures. Neverthe- less, I desire to repeat that, so far as the Dublin supply was concerned in March,! when I made the chief analyses, there was no, need for undue alarm or for exaggerated fears, but rather for much increased caution in dealing with the new gas. On the other hand, monopolies of dwindling value, as gas companies un- doubtedly are, cannot afford to disregard the deliberate opinion of so competent a body as the Home Office Commission. I therefore trust that the 12 per cent. limit recommended for carbon monoxide may not be exceeded in Dublin gas, as it seems an equitable com- promise, and that adequate public supervision of the supply shall be secured and regularly maintained. 1 Tt is unfortunate that the only analysis made in April (on 24th) gave 15-6 per cent. of carbon monoxide, which represents a mixture including about 40 per cent. of carburetted water-gas. [ TABLE 313 Rryno~ps—Recent Analyses of the Dublin Gas Supply. 0-00T || 0-001 | 0-00T | 0-00T | 0-00T | 0-00T | 0-00T | 0-00T | 0-00T | 0-00T | 0-00T | 0-00T || 0-00T | 0-00T { : g : * “oo ‘suIod GGL §-82 G-9), 1-08 €-18 L-18 GG) 6:08 9.8), 9-08 I-78 ¢-¢8 9-18 8-8 -1e001pA TT SUI}VUTUAENTI-U0 | FL bh | GO| &@ | BQ | HE | Sol | Pee] ie | iO | Ooh | Nop I-G | @.F * ‘guoqrvoorpATy SuTpeUrWNyTT ° ° ° ° ¢ 0) || GO | OW | MO | SO | joo | BO | Sx) |) KO | CO | AO | WO I] eo || iO uesfx() 9-CT || §-GI | 6-€1 | G-IT | G-OT | 9-01 | 6-41 | GIT | 9-01 | 8-OL | 9-8 L-8 9-8 GL : : * ‘oprxouoyy toqrep Pl F-G 1-G 1G 0-6 8-1 8-1 9:6 G-G 0° V-G 0-€ G.y 1G ‘ ; * “oprxorqg woqrep UG 16 0G GT 81 OT 6 8 | 4 9 g T LG 66 "SHNATOA OOT NI SEINTALILSNOD “Wady ‘HOUV]L *AUVOAUEH asia aay XXII. ON CERTAIN ROCKS STYLED “FELSTONES,” OCCURRING AS DYKES IN THE COUNTY OF DONEGAL. By GRENVILLE A. J. COLE, M.R.LA., F.G.S., ann J. A. CUNNINGHAM, A.R.C.S8c.1., B.A. (Prares XIX. anp XX.) [Read Aprin 25; Received for Publication May 1; Published Junz 30, 1900. ] Amone the schists and quartzites of the north-west of Ireland, which are grouped together provisionally as Dalradian, a number of igneous dykes occur, which are divisible into three main series. Tirst, there are the basic rocks that were intruded into the sediments prior to the period of their disturbance and meta- morphism. These occur mostly as sheets and sills, but occasionally eross the bedding-planes, or swell out as larger intrusive masses. Their relation to the metamorphic rocks, and the contortion they have undergone, are excellently shown on sheet 11 of the 1-inch map of the Geological Survey of Ireland, in the region west of Rathmullan. These rocks are now mostly in the condition of epidiorites and hornblende-schists, and have probably supplied many of the dark inclusions of amphibolite that are found in the intrusive gneiss of Donegal. The second series of dykes is described in the publications of the Survey by the convenient field-term of “felstone.” The mapping of this system of dykes shows that they belong to some period later than the general folding. One of them, for instance, in sheet 11, cuts right across the contorted epidiorites. Dr. Hyland has noted,’ moreover, that these later intrusive masses do not show signs of mechanical deformation. At some points, as in the south-west of sheet 24, the ‘‘felstones’”’ have been faulted; but _ +See G. Cole, ‘‘ Metamorphic Rocks in Tyrone and Donegal,’”’ Trans. Roy. Irish Acad., vol. xxxi. (1900), (in the press). * Geol. Survey of Ireland, Mem. Sheets, 3, 4, 5, 9, &c., p. 143. Cote & CunnincHAM—On Certain Rocks styled ‘‘Felstones.” 815 the same faults cut the Carboniferous sandstone, and may even be of Cainozoic Age. The Carboniferous beds overlie both the first and second series of dykes, without being penetrated by them. The third series of dykes includes the intrusive basalts and dolerites that follow so persistent a north-west and south-east trend throughout ourislands. These are now generally admitted to belong to the Cainozoic epoch of activity. Associated with them are one or two veins of rhyolite-pitchstone, the characters of which are thoroughly in harmony with those of undoubted products of our Cainozoic voleanoes.t The dolerite dykes of this series cut through the felstones, and are clearly of later date. It has been recognised in recent years that the “ felstone” series of the north-west of Ireland contains rocks of somewhat dissimilar character. In 1888, Messrs. Mitchell and Kilroe? described several masses in the area of Barnesmore as mica-trap, porphyrite with hornblende, syenite with quartz, &c. + ‘193yeu pepuedsngs jo sooviy {yur} uws0erd ystmozpd ‘prqany ApQYsITS ‘uotsuedsns Ut suigap atqejesaa Fo £41} -uvnb yews {qur} weer aaTjo ‘prqiny ApyouTZsIq . . “pIqin} oLOUl o[}4T] v qnq “g ‘ON 0} qElTUITS ‘skep ey Suid ‘1eyyvu ~popued “sus JO sooviy { mopood uMOIq ‘piqany AY SITS > £t9998U popuodsns Jo SOOVAY £ JUTZ UMOL YSTMOT -od ‘prqaug AGUsips Ar A * + “199}8u popuedsns yo saovt, $7UTZ Users ystmorqod ‘prqany ATL YSITY = | = = = Gg0. | 08@0- | 66-FI | ¥F-0 | 9-92 0-0 vel 6L0- G0: 190: 8600- 66-P1 66-6 P9-GL ae a = sa DFO: 0100: 61-41 16:6 81-49 = G66-1 Gc: GO: UF0- GE00- LG-G1. 99: 08-69 Pe a — a T10- GE0- 8-41 90-1 19-SP v-81 96-1 [80- GO: 960- G00: 69-41 86-¢ LY-&¥ ea eae se =e L&0- P00: 69-ST 06-9 89:-GP 0-81 96:1 AU €10- 860- P00: 6G-GT 69-2 10-17 =e eae a Be Gé0- BOO: GV-GL bG-9 GL:GP 0-81 | G0G-T 660- 660: LG0- F00- geal 6F-L 8&-1F aa = =e fa GOV0- ¢100- I1-¥I 86:6 ¥8-69 = [66-1 LiG0- 800- GLE0- ¢P00- IL-71 8hG 79-09 = are = = G8E0- ¢100- G6-F1 88-0 61-69 ar 96-1 GG0- $00. OFE0- 0V00- zonal G6.G 8L-8¢ *uo1yN[OS suedane ‘SOJBIJIN | VIUOWULYy eros *oulto[yD ‘usSO1zIN | ‘UadAxO anes i Ul UDSOIIN OLULSIQ Sv UdSOIJIN ‘uoditosog *1OJEM OY} jo 000‘oor aad szied sv possoidxe szuanzysuod 19yIQ *1042M JO SOWIN|OA ooor 10d *q' TN 3B sourmyoa Sv possvidxa sasex) psalossiqd “Avp SULMOT[OF OY} UO pajoa|joo svM J eTdues eLozoq uoT[yy pey urvc AAvoy pus ‘pojoe]]00 SUTeY SUM g o[duIvs MOYM Yvotq 0} poououmtod ysul pey 4t £499] 19q0}0¢Q UO pu 4sTZ r9que}dog uo YJoq Arp SUA OyYvOA OTT, ‘sAvp g sutdoax 10938 0991q “UV JUS oy} Tou ‘TLO\\ 94} SAOq’ ysne ‘sAvp 6 Sutdooy, 1097v 0941 “PZ 990 ‘yury Surjnq -LIJSIp FO W0}j0q WoAY ‘sAvp e] Surdooy 10978 0991(7 *yURq JULSTI oy} Iwou “110A 94} O9AOGUV ysne ‘sAup 21 Sutdooy 1037v 07917 “OT “420 ‘pozijedeyy Aopeq ysnp doy Loe 0991 ST “490 ‘poztjaduyg oAoqe ysny ‘sAup ge Surdooy 104g 01] "1Z “ydog ‘yun} SUYNGLystIp oq} JO Woxj0q oy} Wol,] > ‘stup pe Sutdeoy 10978 0941 “B68T ‘IZ “deg ‘yueq Jysit oj rwou “IIOM OY} oAoge ysn¢’ *pozoaq[oD e10 ‘SATANVS ‘ON “UNQNE 0) “Ab plug” PUnpsy 7 LOA, oY}p 2d0gn NhafvT woany ay, mouf pagoopjod any fo syduugy fo soshjuup—T a1Aavy, pn ce l AI cl a a ee let - ApEnry— Studies in Chemical Analysis of Fresh & Salt Waters. 351 The composition of the dissolved gases, however, before and after fermentation, show a marked difference, and indicate, when taken into consideration with the inorganic nitrogen compounds, the presence of very decided quantities of fresh organic matter in sample 1, and show also that the quality of sample 2, is much better than that of sample 1. The difference in composition of the dissolved gases also affords the means of estimating exactly the quantity and character of the polluting matters in each sample. No. 1, for instance, is shown to have undergone a very decided fermentation on keeping, - during which nearly the whole of the dissolved oxygen had been consumed; and the fermentative process is shown also to have consisted of both a carbon fermentation and a nitrogen fermentation. We may also conclude from the relative proportions of carbon and nitrogen fermented that the unfermented organic matters, originally present in the water, were of vegetable origin. The analysis of sample 2 shows that the fermentative process which went on in the sample, when kept, was almost entirely confined to a nitrogen fermentation, and that consequently but little, if any, unfermented organic matter was originally present in the sample. The carbon fermentation in this sample had, no doubt, taken place during the time of storage in the distributing tank. I ought, perhaps, to explain the particular meaning I attach to the terms ‘carbon fermentation’ and ‘nitrogen fermentation ’ before proceeding further. I have used these two terms to indicate the two progressive steps in which the bacterial fermentation under complete aérobic conditions of organic substance and of ammonia takes place. The organic substances are first completely broken down, and oxidized almost entirely into carbon dioxide, water, and ammonia. Traces of oxidized organic matters are also formed, and these undergo a more or less complete further oxidation into carbon dioxide and nitric acid during the subsequent fermentative process of the oxidation of the ammonia into nitric acid. Thus during the first step of the fermentative process, the oxidation of the unfermented organic carbon is the main factor of the process; while the oxidation of the ammoniacal nitrogen into nitric acid is the main factor of the second step of the fermentative process; SCIENT. PROC. R.D.S., VOL. IX., PART III. 2C 302 Scientific Proceedings, Royal Dublin Society. hence the terms ‘ carbon fermentation’ and ‘ nitrogen fermentation ’ which I have employed. When the ascertained consumption of oxygen covers both fermentative processes, the loss due to each process may be calculated with sufficient accuracy for practical purposes on the assumption that the loss due to the nitrogen fermentation is equal to the volume of oxygen theoretically required for the direct oxidation of the quantity of ammonia found to have been oxidized by fermentation. (I have fully treated this question in my original paper.) The samples 3, 4, and 5 in Table I. were all collected on Octo- ber 16th, and in dry weather. Their analyses again illustrate the very great value of dissolved gas determinations before and after fermentation. They indicate a very great difference in quality between samples 3 and 4 on the one hand, and sample 5 on the other. In sample 3, a slight fermentation took place on keeping, but it was practically confined to a nitrogen fermentation. In sample 4 the fermentation was more decided, and it consisted of a slight carbon as well as a slight nitrogen fermentation. The analysis for sample 5 shows not only a very decided fermentation, but also that it was entirely confined to a carbon fermentation. As a matter of fact, 0°28 part of carbon per 100,000 parts of the water underwent fermentation, and ‘033 part of nitrogen were converted into ammonia during the process, but it is to be noted that about one-third of this nitrogen was derived from nitrates originally present, and only two-thirds from unfermented organic matter. The analyses therefore show that the ratio of carbon to nitrogen in the unfermented organic matters originally present in the water was 1:10, a ratio which, taken together with the fact that the organic matters were unaccompanied by ammonia, proves them of vegetable origin, and that they were not derived from sewage. As a matter of fact I may explain that they were due to decaying vegetable matter of the autumn season. The analytical details for samples 6 and 7 further illustrate the valuable and definite results obtainable by the aération method. I need only refer to one point in connexion with them. Sample 6 was collected on October 25th, when rain was commencing to 1 Trans. R.D.S., vol. v., pp. 598-604. AvENnEY—Studies in Chemical Analysis of Fresh & Salt Waters. 353 fall after a somewhat lengthened period of fine dry weather, and at a time when rain had commenced to affect the water in the upper reaches of the river. Sample 7 was collected on the following day, after heavy rain had been falling for some hours previously. I mention these points to draw attention to the marked influence of the rain upon the quantity of carbon dioxide in the water at the commencement of the autumn season. APPLICATION TO THE Stupy oF A PorasLE WATER-SUPPLY. The next subject of examination which I wish to notice is that of the Rathmines water-supply, and I notice it in order to illustrate the value of a knowledge of the composition of the dissolved gases in certain cases of doubt in connexion with potable waters. The Rathmines water-supply is an upland surface-water of excellent quality, the catchment area being most carefully guarded against contamination of sewage matter of any kind. In June and the early parts of July of last year, serious complaints were made by the residents of the Rathmines district, that the water as supplied to them was turbid and decidedly coloured, and often emitted unpleasant fish-oil odours, and even at times developed oily scums on its surface when drawn in large quantities for bath purposes, &ec. On investigation, the bad appearance and odour complained of were found to be due to unusually luxuriant growths of microscopic organisms of various kinds, but chiefly of Algw and Diatoms. The water at the time was unfiltered, and consequently the consumers experienced to the full the effect of these luxurious growths immediately they began to die down and decay. The Waterworks comprise two reservoirs: the upper reservoir situated at Glan-na-Smol, Co. Dublin, and forming the storage tank, is 50 feet deep in the deepest part, and possesses a storage capacity of 850,000,000 gallons; and the lower or service reservoir, situated nearer Dublin, at Ballyboden, which has a storage capacity of 11,000,000 gallons. The microscopic growths were particularly luxuriant in this latter reservoir, so much so, indeed, that the stones all round it, from the surface to a depth of 18 inches, were completely covered with a most luxuriant growth of filamentous Algze. Oe Scientific Proceedings, Royal Dublin Society. 304 ssayraqrr peureytioa sopTTures oy} JO OO NAL Ny “USSOMLU POATOSSTP OY} JO eSOUY F[ey-9U0 07 [eube OOM UOTVeInjzes LO¥ portmber UaSAXO JO sowNIOA oy} ey} UoldumMsse oY} uodn poze[NoTVo useq SAVY UUINTOO sTyy UT SeANSY oy, z : “sisAyeue o1ojoq sAup QT ydoy o1om » pure ‘9 ‘Gc sojduyg , ; “AjoAyyoodses ‘G0. “GHO- “EO. “GHO- PUL ‘800. ‘100+ “GTO: ‘TO. 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Samples 2 and 8 were drawn from the lower service reservoir. The other samples represent the condition of the upper storage reservoir. On comparing the analyses recorded in the table, it is at once seen that the water from the upper reservoir, during its passage through the lower reservoir, received a marked addition of polluting matters; but I am more concerned at the present to draw attention to the value of a knowledge of the composition of the dissolved gases in the samples 5, 6, and 7 from the upper reservoir. . These were all collected on the same day, namely July 24th, and represent the condition of the water in the reservoir at two different levels below its surface—sample 5 at about 5 feet below the surface, and samples 6 and 7 at about 20 feet below the surface. Sample 5 may be fairly taken to represent the average condition of the water as it entered the reservoir through the ceatch-water channels. Its analysis shows it to be slightly different in quality from the samples 6 and 7 from the 20-foot level. The analyses of the two latter samples indicate the existence of slight quantities of polluting matter at the lower depths of the reservoir; but with a knowledge of the composition of the dissolved gases in addition to the ordinary analytical data, we find that an active state of both carbon and nitrogen fermentation was taking place in the lower levels of the reservoir, and that the carbon fermentation was practically wholly due to vegetable débris. The dissolved gases determinations also afford the necessary data for distinguishing the proportion of the dissolved oxygen consumed by the carbon fermentation from that consumed by the nitrogen fermentation in the manner I have described above. APPLICATION TO THE STUDY OF THE WATERS oF A TIDAL River. The third subject of study which I have to notice is the tidal portion of the river Liffey, or rather its estuary. 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GTL-1 "OORT, GIG: 00-0 66-0 C88-6 ili G88-G €9-0 86-1 8608 G09G LLG PSPS 6LST O&él 60ST OGEL LOGT 960: ré0- FE0- 090: LE0- 100: 960- 810- ¥00- 600: P00: 600: Té-F1 ¥8-V1 06-FI €8-P1 96-1 1-98 69-68 66-86 40-02 09-92 81-9 86- Xen) 19-9 6I- Xe) 61-G 96°¢¢ 60-1¢ 6G-9G GI-GG 66 p 66 a Ce e “sep @ Fe.1G SS @ 2 9 9 9 OGRE IATO|VO fprqany Aue wed GGG ye ‘eovjans MOTO yoo PL “Moqiey, esnoyzT aoestg eytsoddo ‘fom “URYo-pIM “TTeFNG esoqy SSO [UO DO) ‘prqmy Aysyg ud Jeep ‘eovzims je ‘01 . ° . ° ° ° . *S89] -mopo ‘avotQ ‘urd egy ye ‘eovyins oy MOTE 409F FI ‘T Aonq -JYSIT Ivou ‘jeuuvyo-pryq . ° . ° ° . ° ‘SSO -mopo ‘priqiny, wd OSPF 7B ‘sovzims 4v ‘03]1q i ee eSSoTMOpO ‘piqing, wd gzF ye ‘sovyjins AMO[Eq “UL FT ‘T Aonq-7481T ey} pur Te. (8 84} deesgjed Keapra ‘q[eynQ dopog —?) Poe 06 060 Scientific Proceedings, Royal Dublin Society. After the references I have made to the two preceding tables it will be unnecessary to make any detailed reference to these further tables. I need only remark that the application of the . aération method to sea water is attended with results quite as definite and as valuable as those obtainable when applied to the examination of fresh waters. The “ outfall’ referred to in the tables is, I should explain, situated a few yards to the north of the South Wall, and about half a mile below the Pigeon House Harbour. These analyses, besides illustrating the value of the aération method when applied to the analysis of sea-waters, will be found, on careful examination, to afford some valuable evidence upon the question of the disposal of sewage matters from which the heavy solid matters have been previously separated by dis- charging them into tidal waters. It will be seen from the analyses that the effect of the liquid and the lighter solid sewage matters discharged from so populous a city as Dublin and its neighbour- ing districts is confined in calm weather to the surface waters of the estuary, the bottom waters being but slightly affected even at low tides. ‘Thus in samples 9 and 10, Table IV., the percentage of oxygen found in a sample of the surface water, collected at low spring tide opposite the Pigeon House Harbour, and in calm weather, was 9°9, after it had been kept for five days out of con- tact with air, while the percentage of oxygen found in the sample collected at the same spot, but 14 feet below the surface, was 86°37. ERRORS ARISING WHEN THE OxYGEN ONLY OF THE DiIssoLVED GaAszEs Is DETERMINED. One further point which these analyses illustrate, and which must be here emphasized, is the nature and extent of the error to which I referred in the earlier part of this paper as more or less seriously affecting the results obtained by volumetric methods for dissolved oxygen. The practice hitherto amongst analysts for the estimation of the dissolved oxygen in a water when such has been necessary, has been to adopt one of the volumetric methods, and to employ, for the purpose of calculating the quantities of oxygen found into percentages of saturation, tables giving the maximum quantities of oxygen which distilled water holds in solution when saturated, at different temperatures. Apvrnry— Studies in Chemical Analysis of Fresh & Salt Waters. 361 Although it is well known that accurate determinations of the actual quantity of oxygen dissolved in the water may be made, within certain limiting conditions, by Schiitzenberger’s, or by Thresh’s, volumetric method, a serious difficulty arises when it comes to the question of the standard of oxygen saturation to be taken for the purpose of calculation. This becomes evident immediately it is remembered that the composition of the dissolved gases in still water alters very slowly with alterations of tempera- ture, so that samples of a good fresh river water may be, and probably always are, either over-saturated or under-saturated with oxygen for the temperatures of the water at the times of collection. When it happens that the waters examined are pure sea water, or mixtures of sea and river waters, such as in tidal rivers, the error becomes still more serious, since the solubility of atmospheric oxygen is very much less in sea water than in fresh, temperature for temperature. If, however, the dissolved nitrogen, as well as the oxygen, be determined, we have thereby the means of calculating whether the volume of dissolved oxygen found does actually represent the state of oxygen saturation for the conditions to which the water had been subjected at the time it was collected, or of calculating, if it does not, its exact amount below that state. The truth of these statements will be apparent from the follow- ing table, showing the solubility of atmospheric nitrogen and oxygen at different temperatures in distilled and in sea waters :— The gases are expressed in c.cs., at N.T’.P., per 1000 c.cs. of water. Sea-water.? Distilled water.? Temperature. Sea-water. Distilled water. Nitrogen.| Oxygen. | Nitrogen.] Oxygen. N No PO, 12-4 6°45 15°47 7°87 O02. = —— ~ we d 1-933 1-966 Ne N 19? Ce 11°34 5°83 13°83 7:09 On = 1:945 1:951 Ne Ne 0° C. “41 ‘31 12°76 6°53 ,= = = Z EY : : Ye 1:960 1°954 z No No HC. 9-62 4°8 11°81 5°97 2,= : O2 1-975 1-978 1 Dittmar, “‘Challenger”’ Reports, p. 224. 2 Roscoe and Lunt, Journ. Chem. Soc., 1889, 552. foe XXVI. NOTES ON TEMPERATURE OBSERVATIONS MADE AT DUNSINK OBSERVATORY DURING THE ECLIPSE OF THE SUN ON MAY 28, 1900. By C. MARTIN. (Puate XXI.) [Read Junz 20; Received for Publication Junn 22 ; Published Octozrr 17, 1900.] OpsERVATIONS of temperature were made at Dunsink Observatory during the recent eclipse of the Sun. The observations were taken with two heat radiation thermometers, one with a black bulb, and the other with a white bulb, kindly lent to the Observatory by Professor Fitz Gerald. These thermometers were mounted about an inch apart on a post a little over six feet high. The post was painted black, the bulbs of the thermometers being 6 inches away from any part of the woodwork, and pointed directly towards the Sun. It was intended at first to take readings every fifteen minutes, but owing to clouds the readings were sometimes made oftener. Observations were started at 1.45; but from that time till 2.30 there were a good many clouds about which obscured the Sun every few minutes, so the readings at that time are not of much value; but from 2.45 to the time the observations were discontinued at 4.45, the Sun was free from clouds, and the observations seem very good. From the curves drawn (see Plate XXI.), it will be seen that about eight minutes after the middle of the eclipse the tempe- rature was at its lowest, and began to rise rapidly as the portion of the Sun eclipsed became less. It will also be noticed that as the Sun became more eclipsed the temperature fell quickly. The highest reading before the eclipse began was 63°-7, and the lowest 35°-7, showing a drop of 28° with the black bulb thermometer ; with the white bulb the highest reading was 15°-6, and the lowest 8°, showing a drop of 12°-6. Experiment was made by shading the thermometers to find how they were affected. It was found that on an average the black bulb Marrin— Temperature Notes on the recent Eclipse of the Sun. 363 thermometer fell 6°-4 after being in the shade for one minute, and the white fell 2°-7 in the same time. : SUIMYE AU] ssl | z On annexed figure are 2 given two curves showing 4 the comparison of the two | thermometers used. These were made by taking the =;— i eS lowest reading of each in- strument from each of the Z other readings. Thesums | om of these differences were | < —Proc R.D.S., V., 1886-87, p. 639. ‘*A Lecture Note on the Relation of the Theorem of Work to the Theorem of Moments.’’ —Proc. R.D.S., VIII., 1893-98, p. 167. “On the Continuity of Isothermal Transformation from the Liquid to the Gaseous State.’’—Trans. R.D.S., VI., 1896-98, Ser. II., p. 119. ‘¢On the General Extension of Fourier’s Theorem.’’—Phil. Mag., vol. 43, 1897, pp. 281 and 468. THE SCIENTIFIC PROCEEDINGS OF THE ROYAL DUBLIN SOCIETY. Vol. IX. (N.8.) FEBRUARY, 1903. Part 9. CONTENTS. XLIV.—On Haze, Dry Fog, and Hail. By W. N. Harrtey, D.Sc., F.R.S8., Royal College of Science, Dublin, . XLV.—The Nebula surrounding Nova Persei. By W. E. WI1son, F.R.S., XLVI.—Method of observing the Altitude of a Celestial Object at Sea at Night-time, or when the Horizon is obscured. By J. Joty, D.Sc., F.R.S., F.G.S., ete., Hon. Sec., Royal Dublin Society, XLVII.—On the Progressive Dynamo-Metamorphism of a Porphyritic Andesite from County Wicklow. By Henry J. Szymovr, B.A., F.G.S. (Plates XXVI. and XXVII.), XLVIII.—Some Results of Glacial Drainage round Montpelier Hill, County Dublin. By W. 8B. Wrienur, B.A. (Plates XXVIII. and XXIX.), XLIX.—On the occurrence of Cassiterite in the Tertiary Granite of the Mourne Mountains, County Down. By Henry J. SzyMour, BAC) HIG. Ss, PAGH 547 556 559 568 575 583 Fhe Authors alone are responsible for all opinions expressed in their Communications. DUBLIN: PUBLISHED BY THE ROYAL DUBLIN SOOIETY. WILLIAMS AND NORGATE, Ati 14, HENRIETTA-STREET, COVENT GARDEN, LONDON? 20, SOUTH FREDERICK-STREET, EDINBURGH; anp 7, BROAD-STREET, OXFORD. 1908. Price One Shilling and Sixpence. Roval Dublin Society, FOUNDED, A.D. 1731. INCORPORATED, 1749. awa EVENING SCIENTIFIC MEETINGS. Tuer Evening Scientific Meetings of the Society and of the associated bodies (the Royal Geological Society of Ireland and the Dublin Scientific Club) are held on Wednesday Evenings, at 8 o’clock, during the Session. Authors desiring to read Papers before any of the Sections of the Society are requested to forward their Communications to the Registrar of the Royal Dublin Society at least ten days prior to each Kvening Meeting, as no Paper can be set down for reading until examined and ' approved by the Science Committee. The copyright of Papers read becomes the property of the Society, and such as are considered suitable for the purpose will be printed with the least possible delay. Authors are requested to hand in their MS. and necessary Illustrations in a complete form, and ready for transmission to the Editor. [ or 4 XLIV. ON HAZE, DRY FOG, AND HAIL. By W. N. HARTLEY, D.Sc., F.B.S., Royal College of Science, Dublin. [Read Novemprr 20; Received for Publication, Drcemprr 13, 1901; Published Frsruary 27, 1902.] Tue work of Mr. John Aitken, F.R.S., on Dust, Fogs, and Clouds’, led him to the conclusions which here follow :—first, that wherever water vapour condenses in the atmosphere, it always does so on some solid nucleus; secondly, that dust particles in the air form the nucleus on which vapour condenses.? The sources of atmospheric dust, besides ocean spray which becomes converted into a fine dust of salt, are the the products of com-. bustion, together with almost all substances which are strongly heated, since these have been shown to contribute minute solid particles to the atmosphere. ‘The fewer the dust particles, the more moisture condenses upon them, and they thus become heavier and fall. The more numerous they are, the less is the moisture condensed upon each of them, so that they remain suspended as fog, instead of falling as rain, hail, or sleet. These islands are seldom free from cloud, rain, or fog, and minute quantities of dust, in a more or less moist condition, are nearly always present in the upper atmosphere. Observations on the number of dust particles in measured quantities of air have been made for some time past on the summit of Ben Nevis. The prevailing winds with us are the west, south-west, and south ; and the warm moist-laden air of the Atlantic is the cause of the condensation of aqueous vapour upon the dust particles. 1 Abstract, Proc. Roy. Soc. Edin., vol. xl., p. 14 (1880-1881). * More recent experiments have shown that when air is filtered or washed so that it may be believed to be free from dust, a sudden expansion of saturated air causes the formation of a rain or mist. The expansion required being in the ratio V2/V1 = 1:252, where V1 is the initial and V2 the final yolume. This does not however affect the question of dust-laden air. C. T. R. Wilson, Phil. Trans. vol. 189, p. 265, 1897; also vol. 193, p. 289, 1900. SCIENT. PROC. R.D.S., VOL. IX., PART V. el 548 Scientific Proceedings, Royal Dublin Society. The dust particles themselves may have originated in salt spray from the ocean, carried up in equatorial regions, and from which the heat of the sun has evaporated the water. Consequently, a cloud may consist of moist crystals of salt; and by the accumula- tion of more water upon the nucleus or salt crystal, it may become a minute drop, consisting of a solution of salt. This may condense a still larger proportion of water, and become a drop of rain, and that this is the case there is evidence in the fact that rain-water always contains sodium chloride; but a drop of rain does not generally contain any appreciable solid nucleus in- soluble in water, when the clouds from which it fell are travelling with our prevailing winds. Atmospheric dust may thus be said to be of two kinds, that which is soluble, and that which is insoluble in water. Let us deal now with that which is insoluble. At Palermo, on March 10th, 1901, a dense lurid cloud hung over the town, the sky appearing blood-red. ‘There was a strong south wind, and drops of rain fell, having the appearance of blood.’ The phenomenon was attributed in that locality to red dust, carried up from the sands of the Sahara.” At Naples showers of sand fell while the sky was of a deep red colour. From Algiers, reports of a similar occurrence in North Africa were received. Fine sand carried to a great height in the atmosphere is sustained by reason of the viscosity of the air and the minute dimensions of the particles. The condensation of moisture upon them increases their size and weight, and causes their descent as rain; otherwise they settle down more slowly, and travel farther by the operation of air currents. | Hellmann and Meinardus have shown the hours at which red and grey sand showers fell in North Germany, which came from the same source as that in Southern Europe.? Several analyses have been made, and also examinations with the microscope, with the result that the dust was shown to contain 1 The Times newspaper. 2 Nature, vol. 63, p. 471. 3 Dr. Hellmann’s Meteorologische Zeitschrift, ‘‘ Der Staubfall vom 10. und 11. Marz 1901.”’ Harriteyv—On Haze, Dry Fog, and Hail. 049 felspar and quartz sand, or in other words, it was a red felspathic sand, such as is found in the desert of Sahara and in Egypt. Black rain falls occasionally at distances apparently remote from manufacturing centres. Rain of this character, accompanied by intense darkness, descended upon an area of nearly 500 square miles in the North of Ireland, in February, 1898, during a spell of north-easterly wind. In May, 1899, an equal area in central and south-western England received a similar fall. ‘he precise atmospheric conditions necessary for raising of dust or smoke into the upper parts of the atmosphere, and the con- centration and descent over special areas, is not fully understood. On December 27th, 1896, there occurred over Melbourne and a considerable area of Victoria, an unusually heavy fall of dust of a red colour, which was carried down by accompany- ing rain. This was examined microscopically, and found to contain diatomaces ; it was therefore of terrestrial origin. Its chemical analysis, made by Mr. Thomas Steel, F.c.s., showed that it agreed closely with the composition of volcanic soils from such widely separated localities as Northern Queensland, New South Wales, and Fiji.’ In such facts we have abundant evidence of the transference of great bodies of dust from the Harth’s surface to far distant regions by the operation of gentle air-currents. In February last, I communicated to the Royal Society a paper, by Mr. Ramage and myself, on the mineral constituents of dust and soot from various sources.* Dust was separated from hail, rain, and sleet which fell in Dublin ; voleanic dust came from different sources, and pumice from Krakatoa. We collected soot from different chimneys, flue- dust from gas works, from iron furnaces, and from copper- smelting works. Flue-dust from vitriol works, and iron pyrites from coal, also the dust from coal ashes were analysed. The localities from which the specimens came were situated in Ireland, England, Wales, the United States, New Zealand, Krakatoa, Vesuvius, and South America. We also examined meteorites 1 Nature, vol. 63, p. 472. 2 Australasian Association for the Advancement of Science, January 10th, 1898. 3 Proc. Roy. Soc., vol. 68, p. 97, 1901. 2T 2 000 Scientifie Proceedings, Royal Dublin Society. found in different localities ; for one of the objects of this work was to ascertain whether meteoric dust descended upon the Earth, and this could only be done by ascertaining whether dust from terrestrial sources resembled in composition that known to be of meteoric origin. The method of examination was by spectrographic analysis, which is of extreme delicacy, and practically the only means available for investigating the composition of complex substances, with very minute quantities of material, such as could be obtained from hail-stones and drops of rain. The largest quantity of material derived from such a source was 0:08 gr. The spectra photographed were obtained by burning in the oxyhydrogen flame the substance wrapped up in, or distributed over, the surface of an ashless filter-paper. From the number of lines observed belonging to the different elements which can be photographed in this way, also from their relative intensities, the proportions of the different substances present could be ascertained, and the different spectra could be compared. It thus became evident that different kinds of dust could be broadly classified according to their composition, and their origin ascertained. It may be well to remark, at this point, that arsenic and antimony cannot be detected by this method when present in minute proportions, and that a chemical method, such as Marsh’s test, is more sensitive than either the spark or flame-spectrum of arsenic. . There are two samples of dust which, on inspection, appeared to be of an unusual character, to which attention may be parti- cularly directed. (I.) Solid matter which fell in or with hail in a hail-storm on Wednesday, April 14th, 1897, and was collected by Professor O’Reilly at a window facing the large open space of Stephen’s Green, at the Royal College of Science, Dublin. It contained iron, sodium, lead, copper, silver, calcium, potassium, nickel, manganese (a trace) ; gallium and cobalt gave doubtful indications. (II.)} Solid matter from hail and sleet collected by Professor O’Reilly on plates upon a window-sill of the Royal College of Science, Dublin, during a very heavy shower, from 2.30 till 3 o'clock, in the afternoon of March 28th, 1896. Total weight of the dust 0°1018 gramme, of which 0:08 gramme was burnt in the oxyhydrogen flame. The colour of the Hartisy—On Haze, Dry Fog, and Hail. 551 dust was steel-grey and it was magnetic. It contained iron, copper and sodium, lead calcium, potassium, manganese, nickel, silver, thallium (a trace), gallium, and rubidium (a trace), doubtful. As II. contained thallium, a substance found in pyrites flue- dust, it is evident that it might be precipitated from the atmosphere in a neighbourhood where sulphuric acid is made ; but as the flue-dust from vitriol works in Dublin contains a notable proportion of indium, the absence of this element pre- eludes the possibility of I. and II. having come from them. Volcanic dust is distinguished by the very small proportion of the heavy metals, lead ‘and iron for example, and the principal constituents being lime, magnesia, and the alkalies. Dust from the clouds shows a certain regularity in composi- tion, whether it has fallen directly, or been carried down by rain, sleet, snow, or hail. Hach specimen, out of several, appeared to contain the same proportions of iron, nickel, calcium, copper, potassium, and sodium. ‘The proportion of carbonaceous matter is small. The samples collected from hail, sleet, and snow differ from one another, and differ widely from other specimens, by reason of the large proportions of lead which they contain. It need scarcely be mentioned that different specimens of soot differ very widely in composition, even when taken from different chimneys in the same house. ‘The quantity of the metals, such as iron, lead, copper, silver, &ec., differs with the amount of carbon in the soot. Having pondered over the subject, I will now proceed to state the conclusions arrived at after collecting together the results of numerous and varied observations. Dry Dust.—Fume of whatever kind, condensing to solid matter, causes the formation of a dry dust, provided such condensation takes place in a dry air. Then the proportion of moisture condensed on the solid matter is small; the result, as Aitken has shown, is a mist or fog; if large, it is a cloud; if still larger it may become’ hail, rain, or snow, according to the temperature. Shortly, however, it may be stated that what appears as mist low down on a mountain, exists as snow at a greater elevation where the air is colder. Dry dust may be seen in the air as a distinct discoloration of the sky. It may arise from the blowing away 902 Scientific Proceedings, Royal Dublin Society. of the pollen or the bloom from flowering plants, and this some- times is seen in hot dry weather on the moors and mountains of Scotland, when the heather is in full bloom. Sometimes a dry dust may be observed in the upper stratum of the atmosphere, which largely consists of the spores of fungi, and with a moist air at lower levels and a high temperature, such a cloud becomes blight. Dry dust may also arise from the smoke of towns, or the condensation of fume from metallurgical works, or from the finer particles of dust from the smoke-shafts of factories, but which differs from smoke in its comparative freedom from carbonaceous matter. Such dust is visible in the neighbourhood of manu- facturing towns. Wet Dust.—Wet dust, such as that I now refer to, accompanies rain, hail, or snow in its descent upon the Harth. The dust from hail and sleet, suddenly precipitated, differed in composition from any other form of dust which was collected from the atmosphere in or near Dublin, during the course of the investigation referred to above, by reason of the large proportion of lead present. In this respect it resembles dust from the flue of an assaying furnace, where lead ores are constantly melted in considerable quantities, and lead fume is seen to rise from the crucibles when they are uncovered. It also resembles the dust from the flue of a gas- - muffle furnace, in which lead is oxidised and volatilised when cupellation assays are made. We could imagine the possibility of dust being brought down by means of sleet shortly after its escape from the laboratory chimney ; but on careful consideration of the facts, this appears to have been impossible with the particular samples of dust which were obtained from sleet. With hail-stones, in which the mineral particles are the actual nuclei, and so are contained within the spherules of ice, such a source of fume as a neighbouring chimney cannot be considered as having provided them. At first sight the following fact appeared to be a possible explanation of the com- position of this dust. About five miles to the south-east of Dublin lie the disused Ballycorus lead mines, in the neighbourhood of which lead smelting to a very limited extent is still carried on. The flue for condensing the fume runs up the surface of a hill for about half a mile, and terminates in a vertical shaft on the summit. When this hail, which has been mentioned, was collected, HartiEy—On Haze, Dry Fog, and Hail. 5d3 a small quantity of fume had been seen occasionally to escape from the shaft. Hail and sleet falling in Dublin came from the east or south-east, and therefore lead fume diffused through the air might possibly be mixed with any dust travelling with the wind upon which moisture would condense and freeze. But hail appears to be formed in consequence of very strong local currents driving a body of air heavily charged with moisture to a great altitude, where the moisture is condensed upon the solid particles of dust in the form of ice.1 On careful consideration, it seems most improbable that the actual quantity of lead fume from the particular somrce specified could have been sufficient to diffuse through so vast a space at so great an elevation as the dark cloud was seen to occupy previous to the descent of the hail; and therefore some more extensive and copious source of dust of this composition and at a greater distance from where it fell must be looked for. Such a district is South Wales. In the Vale of Dowlais, in April, 1893, there being an easterly wind and a perfectly cloudless sky with bright sunshine for several consecutive days, it was noticed that the fume arising from the Bessemer works, in operation both there and at Merthyr Tydvil, ascended to a great height as a distinct foxy-red cloud be- fore it dispersed. Since then the same occurrence has been noticed in other districts. It was remarked at the time as continuing in this state for some three or four hundred feet above the works ; but this was really a minimum estimate made from sketches drawn on the spot, and it falls very considerably short of the height at which the dust diffused. A thin widely-extended haze appeared in the blue sky at what could not have been less than 4000 or 5000 feet above the Harth, if we may judge from the known distance of the observer from the source of the fume and the apparent height of the mountains of. known altitudes and at similar distances. This haze showed no tendency to settle, but wafted slowly to the westward. In the Isle of Anglesey, in 1896, on the 23rd of May, the atmospheric conditions being precisely similar, that is to say with a feeble easterly or south-easterly wind and a cloudless blue sky, there appeared, high over Snowdon, commencing at about five 1“ Les phénoménes de Vatmosphére, ’? p. 274, H. Mohn. Paris, 1884. 504 Scientific Proceedings, Royal Dublin Society. times the apparent height of the mountain, and extending as high again, a perfectly distinct blackish or grey haze subtending the angle of vision or about 30 degrees on a horizontal and vertical plane. There was nothing resembling it to be seen in any other part of the heavens, and the summit of Snowdon was perfectly clear. Such appearances in Ireland and Scotland have been noticed at much lower elevations, and they arise from manufacturing opera- tions in the neighbourhood of Glasgow, Belfast, or Dublin. Down the Clyde, with an easterly wind, they have been seen as a thick dry haze to extend to Gourock and Dunoon. Occasionally over the sea a haze from steamer smoke is seen, but as a rule it lies much lower than the smoke of towns. Fume from the Bessemer process and from ferromanganese works contains chiefly iron and manganese, with very little, if any, lead; but where such fume can ascend, so also may the lead fume. Other instances of the transference of dust, soot, and fumes may be cited. Thus, on January dth, 1901, with avery gentle easterly wind and a — cloudless blue sky, the fume and smoke from the alkali district of Runcorn and Widnes, with the smoke also of Liverpool, was very distinctly observed from Holyhead to be carried out far into the St. George’s Channel, at no great altitude, and descending apparently to not very far above the surface of the water. It presented the appearance of a reddish brown haze, and was not like that of steamer smoke, which is black or grey. It was evidently dry dust resulting from manufacturing operations carried on in the well-known industrial centres of Cheshire and Lancashire. The smoke of London may be observed high in the atmosphere as soon as one passes the Chiltern Hills, at or about Leighton Buzzard, when travelling southwards. The smoke of Alexandria and of the Vale of Leven is carried up Loch Lomond, and deposited upon the bracken on the western side of the Loch below Luss at a height of about 1000 to 1200 feet. On January 7th, 1901, in Dublin and the district to the east of the city, the sky was overcast but without cloud, and there was a light current of air moving from the east, but no sign of fog near the Harth’s surface. On the following day we received accounts of dense canopies of fog in London, and of similar atmospheric conditions in other parts of England. It appears, therefore, more than likely that this dry dust, smoke, or fume is carried in a body * Hartitty—On Haze, Dry Fog, and Hail. 509 across the St. George’s Channel, but at a great elevation. If the air-current amounts to a breeze, the dust is dispersed through a vast volume of air, and is not visible, and perhaps not otherwise capable of detection. Taking these facts into consideration in connexion with what was observed inthe South Wales district, the conclusion becomes inevitable that the haze was caused by dust originating with fume, which ascended during a period of anticyclone from one of the manufacturing centres of either South Wales, South Stafford- shire, or possibly the pottery district of North Staffordshire. Travelling slowly over St. George’s Channel at an altitude of 10,000 to 15,000 feet, it may readily be understood that aqueous vapour could condense upon it and be precipitated as rain, snow, or hail. Metallurgical operations in the district around Swansea comprise lead and copper smelting; in the potteries lead oxide and alkalies volatilise from the kilns; in iron districts fume arises from Bessemer steel and ferromanganese works. A. very reason- able explanation of the composition and origin of the nuclei of these hail-stones is afforded by these facts. It seems worth while to prosecute this inquiry somewhat further by examining dust collected from the neighbourhood of manufacturing towns, and afterwards in places far remote from them. I believe that from the spectrographic analysis of such dust it could be, in most cases, easily identified and traced to its source. B88) 7 XLV. THE NEBULA SURROUNDING NOVA PERSEI. By W. HE. WILSON, E.RB.5. [Read January 22; Received for Publication, Fepruary 12; Published Aprit 14, 1902.] On the 22nd of last February a new star of the lst magnitude was detected in the constellation Persei almost simultaneously by Dr. Anderson, of Edinburgh, and Mr. Hllard Gore, of Dublin. The outburst seems to have been exceedingly sudden, as that particular region of the sky was photographed in America on February 19th, only three days before, and there is not a trace of the star. The plate was given an exposure of over one hour, so that stars as faint as the 11th magnitude are clearly depicted on it. The new star seems to have attained its maximum brillianey a few days after its discovery, when it outshone stars of the Ist magnitude. It then rapidly waned, and, with some curious fluctuations in brilliancy, is now of about the 7th magnitude. _ In September last, Mr. Ritchey, at the Yerkes Observatory, took a photograph of the Nova, using a reflecting telescope of two feet aperture, and giving the plate an exposure of about 4 hours. He thus found that the Nova was surrounded by a spiral nebula. This was an interesting discovery, as there is some suspicion that these new stars are connected in some way with nebula. On November 9th and 13th Ritchey again photographed the Nova, giving his plates an exposure of about 7 hours. When these photographs were compared with the one of September 20th it was found that the nebula had altered in shape, and expanded in size. This was a most startling discovery, and quite unique in astronomical annals. The only possible explanation seemed to be that the nebula was the result of some terrific explosion of which the Nova was the origin, and that it was in fact expanding in volume like smoke after it leaves the mouth of a cannon. But it Witson— The Nebula surrounding Nova Perset. OOF was soon seen that either the Nova must be comparatively close to the Earth, or else that the velocity by which the nebula was ex- panding must be enormous. If we assume that the Nova is as close to us as the nearest fixed star, the velocity necessary to account for this apparent expansion must be about 2000 miles per second. Such velocities are quite unknown and most improbable. Early iast month the idea occurred to me that this apparent expansion might be due to the illumination of the solid particles of the nebula by the light sent out on the occasion of the outburst of the star, and that if this hypothesis were correct it was possible to calculate the distance of the star from the Harth by means of the observed angular growth of the illuminated ring which must spread out with the velocity of light. I have since found that Professor Kapteyn has quite inde- pendently suggested the same idea, and he can undoubtedly claim priority in its publication. Let D denote the distance of the Nova, and let L be the distance travelled over by light in a year of 365-25 days, #.e. a light year. Let T be the time in days elapsed from the outbreak of the star to the date of the photograph, and let p be the radius of arc in seconds from the Nova to the edge of the nebula, then D 206265 T i 6On@s ) o: ae D = [2:75184] x 2 L, © . : 206265 the figure in brackets being the logarithm of 365-95 The angular distance p of the point marked (A) in the photo- graph of September 20th is almost exactly 480”, and the time from the outbreak is 211 days. This makes the distance D of the Nova from the Earth 248 light years, or 15,780,000 times the distance from us of the Sun. Ii the Sun were removed to this distance its light would be re- duced to that of a star of the 10:24 magnitude, and would be, therefore, quite invisible, except in a telescope of considerable size. The brilliancy of the Nova at its maximum must have been extraordinary. As it appeared to us brighter than a Ist 008 Scientific Proceedings, Royal Dublin Society. magnitude star it must have been more than 10,000 times brighter than the Sun. The most serious question is: Would the nebula be capable of reflecting enough of the light from the Nova to be visible to us? If we take — as the ratio of the light of a lst magnitude star to that of the Sun, then the edge of the nebula being 430 times closer to the Nova than the Earth the light it would receive 430? 1 2 a oe would be 430°, OF 10" ° 970500 Taking Young’s estimate of the light of the full Moon as of sunlight. equal to of that of the Sun, the nebula would receive about 1 600000 2°2 times the light of full Moon. The nebula being of finite area its intrinsic brilliancy would not be reduced by its distance from the Harth, so that allowing for the “albido” of the nebula, or the amount of light its particles are able to reflect as one-half, its particles ought to be in- trinsically as bright as the Moon. SButthe particles of the nebula are evidently widely separated in space from each other, as the nebula seems very transparent. We, therefore, would not probably receive anything like the light of moonlight. The intrinsic brilliancy of the nebula, from the very long exposures required to photograph it, is certainly not greater than an 18th magnitude star ; and as the light of the Nova was about a Ist magnitude one, the amount of light reflected from the nebula seems to be only , and if we take the light of the Nova at its canal ee a 6310000 : ‘ LL maximum as equal to 0°2 magnitude the ratio becomes 18180000 of the light it received from the star. I consider, therefore, that we have very strong grounds for thinking that the nebula is able to reflect enough light to become visible to us, and that this apparent expansion of the nebula is entirely due to the advance of the wave of light sent out by the outburst of the star. It thus becomes possible for the first time to determine the distance of a star whose parallax is unknown. [ oo J XLVI. METHOD OF OBSERVING THE ALTITUDE OF A CELES- TIAL OBJECT AT SHA AT NIGHT-TIME OR WHEN THE HORIZON IS OBSCURED. By J. JOLY, S8c.D., F.G.S., F.R.S., etc., Hon. Sec. R.D.S. [Read Frsruary 19; Received for Publication Fepruary 21; Published May 14, 1902]. ir is a common experience to find clear skies at night-time, presenting to the mariner what would be valuable opportunities for observation, if at the same time the horizon was available. This has led to the invention of many contrivances, depending on gravity or gyrostatic stability, designed to afford an artificial horizon. Any contrivances controlled by gravity must, however, possess vibrational properties which will render their use unreliable. If controlled by kinetic stability or by magnetic force, the correct setting of the instrument to horizontality presents difficulties and uncertainties which have not yet been surmounted. The want being thus not easily supplied by mechanical con- trivances, I describe in this paper a very simple mode of making observations when the horizon is obscured—a mode which demands, it may be said, no special apparatus and no experience or know- ledge from the mariner that he does not already possess; while fairly approximate results are obtainable, which under such con- ditions as would necessitate the use of the method would doubtless possess considerable value. I assume that the vessel is provided with the usual rescue- signals, as certified by the Board of Trade. These signals, when thrown overboard (being first perforated), burn in the water with a bright white light, visible in clear weather up to five miles, and burning in all states of wind and water for about half-an-hour. To one of these is attached some three or four fathoms of marlin, with a small piece of scrap-iron or any other suitable object attached at its extremity. The signal, so fitted, will not drift appreciably with the wind when thrown overboard. Save for 560 Scientific Proceedings, Royal Dublin Society. current-drift it will remain stationary at the spot where it is launched. As will be seen later, current-drift of the signal will not affect the value of the method of making observations now to be described, as the ship may be assumed to drift an equal amount, premising that we speak of ocean-currents. We will assume the mariner is desirous of making a stellar observation at night, when the horizon is obscured. To this end he looks for a recognisable bright star. If nearly astern of his ship so much the better as regards diminishing the time required to make the observation. But the mariner may optionally prefer to select a star near his meridian. Having decided on a suitable star, he takes its bearing, and, altering his course to the opposite bearing, he thus brings the star right astern. He now drops the rescue-signal overboard (having perforated it if necessary), and at the same time a reading of the log is taken. Having sailed or steamed a distance of about a mile from the signal, as indicated by the log, he reads the angular elevation of the star over the signal, using the sextant in the usual manner. In effecting this reading it will increase the accuracy of the obser- vation to heave-to; but this should not be necessary if the star is kept on the signal, as nearly as may be, by shifting the limb of the sextant gradually as the distance increases nearly to the mile ; diminishing the angle till the word is given that the knot is run. The reading being taken, the ship is put back on her course. In this operation it conduces to accuracy if, instead of running directly away from the signal on the exact bearing opposite to that first taken of the star, attention is paid to the fact that the star is not a fixed object, but is travelling east to west at the rate of about 1° in four minutes of time. The amount by which the ship’s course must be altered to counteract this motion and to pre- serve the signal in the vertical plane containing the star will depend on the direction of the ship’s course, being greatest when this is north and south. Unless the ship travels very slowly the error may be sufliciently corrected by keeping the ship’s course a very little to the eastward of the first bearing; in general something less than z; point. The inaccuracy introduced by this procedure into the determination of distance as effected by the log is negligible. Joty—Altitude of Celestial Object at Sea at Night-Time. 561 The altitude so determined, of course, requires a larger sub- tractive correction for “‘dip” than would be required when using the visible horizon. + S31 Fig. 1. Let AH be the sensible horizon or tangent plane to the Harth’s surface at the observer’s position, and AJ’ the line touching the visible horizon vertically beneath the star S,, and reaching the eye of the observer, whose height of eye above sea-level is OA: also let AS be the line extending from the observer’s eye to the signal, which last is also vertically beneath the star. The usual correc- tion for dip is the angle HAH"; while that required by the use of the signal is the angle HAS. The angle HAS, of course, exceeds the normal dip by an amount depending on the proximity of the ship to the signal. Deducting it from the observed reading, S,A8 on the sextant (after this is corrected for instrumental error), the remainder S,4 ZH is the elevation of the object above the sensible horizon. The line OS follows, of course, the curvature of the Earth’s surface. A short table of dips for objects nearer than the visible horizon is given in Norie’s “ Navigation,” and in other works on navigation. A more extended table is desirable for the purpose of the present method. Such a table should read at least to minutes of arc. In smooth water results of considerable accuracy would pro- bably be obtained by the observation as described. If attention be paid to obtaining verticality of the star over the signal, and to obtaining a good reading of distance, and the ship’s way be reduced 562 Scientific Proceedings, Royal Dublin Society. when taking the reading, there seems no reason to expect a less degree of accuracy by this method than in the case of an altitude referred to the true horizon. In rough water a correction, however, becomes necessary, which in extreme cases might render the results uncertain within three or four minutes. S1 Fig. 2. The diagram, fig. 2, shows that the dip &, which we read if we observe the signal when it is on top of a wave, is less than the true dip 6, or the angle that would be read if the signal floated at the mean-level of the sea. A little consideration shows that this is brought about by the fact that the wave brings the signal more nearly into the horizontal plane of the observer’s eye, or, in other words, reduces the vertical height of the eye above the level of the signal by an amount equal to half the wave-height. Neglecting the Harth’s curvature the tangent of the angle observed is no longer OA but C4= OA — half wave- -height OS OS The correction consists in deducting the estimated HAL¥ wave-height Jrom the * height of eye,” and then calculating the dip; or, if refer- ence is made to the table of dips, entering this with the reduced height of eye and taking out the dip for the correct distance. As there is generally difficulty in arriving at a close estimate of wave-heights, even in daylight, and at night, when only by observation of the signal itself, when close to the ship, any estimate could be made, this difficulty is much increased, it is Jory—Altitude of Celestial Object at Sea at Night-Time. 563 necessary to consider what magnitude of error might enter into observations made by this method in fairly steep seas. The table (see p. 564) of maximum error, due to wave-elevation, will give an idea as to the order of the errors arising where only a partial or incomplete correction for wave-elevation of the signal has been possible. The figures given in the table are, in short, the dips due to half the wave-heights. In other words, supposing the signal was always observed when on top of a wave (or, what comes to the same thing, the /east altitude of the celestial object was taken), and no correction made for the elevation of the signal over mean sea-level, then the table gives the error affecting the angular elevation observed, and which would remain after the usual correction for dip in smooth water was applied to this angular elevation. The error is one of deficiency, and therefore the quantities in the table would be applied additively by way of correction. The table is carried so far as wave-heights of 12 feet, although it is probable that in such seas observation of any sort would be open to an equal degree of inaccuracy ; and, indeed, the motion of the ship and its own elevation at the moments of observation would render any sort of angular observation liable to considerable error. It will be seen from the table that in a swell of, say, six feet from crest to hollow, and in the case of an observation at a distance of one mile, the error, if neglected, would falsify a calculation of ship’s position to the extent of about one mile and a-half. Thus in a meridian observation of a star bearing south the distance of the ship to northward is over estimated by this amount. It is evident, then, that in ordinary weather wave-elevation need not introduce any serious error, and would not count against the use of the method under such conditions and circumstances as would in general render its use desirable; that is, in cireumstances where great accuracy was not required, but some fairly approximate idea of the mariner’s whereabouts was desirable or imperative. SCIENT. PROC. R.D.S., VOL. IX., PART Y. 2U 064 Scientific Proceedings, Royal Dublin Society. Tas_E showing the Effects of Wave-elevation of the signal on the observed altitude. Height of Waves, Distance in Miles. erest to hollow : in feet. 1 1k 9 3 2 46” 34” B83” lq? iil” 4 1’ 32” WV 46" 34" 23" 6 2uellou 1 42" WP 51” 34” 8 3 OF BY GY Ww Bil? etait 45" 10 | ag" 2! 50" 1 Gey iY Og 56” 12 4! 32" 3) 23” Zellow V’ 42” fey? In rough water it is more important to increase the distance from the signal than in smooth water. While half a mile, or even less, might give an accurate result in still water; in a sea-way, 1 mile or 13 miles would be desirable. It is to be noticed that some correction reducing the amount of the error will generally be possible. Thus, if a six-foot sea is estimated erroneously to be an eight-foot sea, the error introduced is that arising from the sub- traction of 4 feet instead of 3 feet from the height of eye. This, at 1 mile distance of observation, gives an error of about 34” in the altitude, the altitude being over-estimated by this amount. If the distance from the signal be erroneously determined, of course the dip will be incorrectly taken out. But this source of error need not be serious; for, with a good log, there is no reason to expect even as much as 5 per cent. error. If there was 5 per cent. error in a one-mile run the error will be about 40” in the case of observations made from a height of eye of 24 feet. The error might be completely eliminated in smooth water by attach- ing the signal to a line, and paying-out the line, so that the signal was finally at an accurately known distance from the ship. ‘This procedure appears to be needless in order to arrive at results possessing the degree of accuracy required. An observation of the altitude of a known star will, in general, be an “ex-meridian,” and may be reduced to give latitude in the JoLty—A liitude of Celestial Object at Sea at Night-Time. 565 usual manner. The mariner may, however, require to find his position by a Sumner problem. If a second known star is avail- able, preferably not far from the first star, and he devotes a little longer time to the observation, this may be accomplished, the final accuracy depending chiefly on the state of the sea and the care with which he reads his distance and his angles. The nature of the procedure in taking the altitudes of two stars to work a Sumner is as follows :—Having, as just described, taken the angular elevation of a star, S,, above the signal, the ship is now put in such a course as will bring the second known star, S,, vertically over the signal, while at the same time preserving unaltered the distance between the ship and the signal. The angular elevation of the second star above the signal is then observed, and the same correction for dips applied, when all the data for the problem are obtained. +52 Fig. 3. The figure, showing the successive positions of the ship pro- jected on the horizontal, will explain the principles on which the ship’s course is determined in going from the position where the first observation is made to that in which the second is made. Sis the signal ; S,, the first star ; A, the position of the ship when reading the angular elevation of S,, above S as viewed from the ship. ‘The second star, S., is seen in the direction 48, from the ship at A. The observation of altitude at A being made, the bearings of the two stars are observed. The angle a is thus obtained. Now, if B is the required second position of the ship, the star S, will be sighted vertically over the signal, and the line BS, will be parallel 566 Scientific Proceedings, Royal Dublin Society. to AS, (owing to the great distance of the star), and hence the angle at the vertex of the triangle ASB will be equal to the angle a (the horizontal angular separation of the two stars as seen from A). Now, the triangle ASB is isosceles, for BS is equal to AS. Hence the angles (b) at its base are equal and evidently a+2b=180 or 2b=180-a and b= 90-5. The Rule for shaping the course from A is then as follows :— With the bearing AS lay off the complement of 5 and sail till S82 is over S, when make the second observation ; a being the difference of the bearings of S, and S, as observed from the place of first observa- tion. Of course S,is over S when the angular elevation is the least. In fairly calm weather a plumb line may be used to assist in placing the ship for the second observation. ‘This is not per- fectly accurate owing to the shift of the celestial objects in the interval required to run the distance AB. For example, suppose S, bears HOS, and S, NHDEZE; the 5 19° 40’ nearly. The complement of this is 70° 20’ or 64 points. The bearing of S, being HOS, we lay off 61 points to the south of HDS. The course is therefore S2#; and this course is held till S, is over the signal. The data now obtained are the altitudes of S, and S, above the horizon, the times of observation and the “run” over the dis- tance AB, and made in the direction A to B, between the observa- tions. ‘This distance will have been measured by log, or, of course, it may be computed as the necessary elements of the triangle ASB are known. It may be that the run is negligible if the degree of accuracy required is not considerable. In the usual manner two latitudes are assumed between which or near to which we know the ship to be, and using the altitude and polar distance of S;, we compute the longitudes corresponding to the assumption that the ship is actually in either of these latitudes. Secondly, using the altitude and polar distance of S., we again calculate two longi- tudes corresponding to the two latitudes. After plotting the results one of the “ lines of position ” is shifted for the run (if necessary), and the intersection of the two final lines of position gives the position of the ship. angle a is then 39° 20’ approximately, and Joty—Altitude of Celestial Olject at Sea at Night-Time. 567 The “ double chronometer problem ” may be also worked, using one assumed latitude only, and finding the lines of position by finding true bearings by Azimuth tables, using the declinations and calculated hour angles in the usual manner. I have not in the title of this paper altogether restricted the method to observations made at night-time. In hazy weather, which at the same time may very probably be calm weather, the method is applicable to taking approximate altitudes of the sun. _ In this case the most suitable object to use as a signal would be a spherical or hemispherical bright tin float, but, as such must be specially provided, the use of any fairly bulky and conspicuous object might be resorted to successfully: as a piece of plank with an upright attached and a shape of any kind on top. This being “‘anchored”’ by a length of a few fathoms of marlin and attached sinker, is used asa signal. An ex-meridian (or meridian) observa- tion is best made by sailing from the signal in the manner before described, and when a suitable distance is attained reading the elevation and noting time by “ watch.” SCIENT. PROC. R.D.S., VOL. IX., PART V. 2x [ 568 J XLVII. ON THE PROGRESSIVE DYNAMO-METAMORPHISM OF A PORPHYRITIC ANDESITE FROM COUNTY WICKLOW. By HENRY J. SEYMOUR, B.A., F.G.S. (PratEs XXVI. anp XXVII.) [COMMUNICATED BY PERMISSION OF THE DIRECTOR OF H. M. GEOLOGICAL SURVEY. | [Read Marcu 19; Received for Publication Marcn 21; Published June 28th, 1902.] THE object of the present communication is to describe an in- teresting case of the transformation of a porphyritic basic rock into a banded schist.1 It is also put forward as an exceptionally clear example of an already recognised possible mode of origin of banded gneisses, by the effects of pressure and recrystallization acting on suitable non-homogeneous rock masses or complexes. As has already been pointed out in another publication,’ numerous outcrops of basic rocks occur within a zone, about a mile wide, along the western flanks of the Leinster granite between Brittas and Baltinglass. These rocks were formerly mapped as ashes (Ds.) on the Survey maps (old editions), their apparently bedded character—really a shear structure produced by pressure— being regarded by the earlier observers as pointing to a sedimentary origin. {They are now mainly in the condition of hornblende and mica schists, and epidiorites, and were very probably pyroxenic varieties in their original condition, as is indicated by those examples which, owing to their having been outside the sphere of influence of the granite, have retained more or less their original structures. One such example occurs, amongst other places at Ballina- scorney Gap, west of Glenasmole, thin sections of the rock from this 1T am indebted to my colleague Mr A. McHenry, for bringing under my notice the rock now described. * « Summary of Progress,’’ Geological Survey, 1899, pp. 71, 72, and 176, Seymour—WMetamorphism of a Porphyritic Andesite. 569 locality showing that it was originally an augite-diorite, or dolerite without olivine.’ The amount of alteration produced on these rocks depends on their proximity to the granite. For example, the outcrops over a mile distant seem to be scarcely at all affected, while those some- what nearer have usually been more or less re-crystallized into amphibole rocks. Those, however, near the granite have been, in common with the associated sediments, not only highly thermo- metamorphosed, but also considerably sheared. It may be here _ mentioned that the comparatively narrow extent of the zone of alteration on the western side of the granite of the Leinster chain, as compared with that on the eastern side, is due probably to the much steeper descent of the granite beneath the slates on the for- mer side, as was first pointed out by Maxwell Close in 1877.” These basic rocks all probably belong to the same period, and occur apparently as intrusive sills, bosses, and dykes, in sediments believed to be of Lower Silurian (Ordovician) age. Some, how- ever, may possibly be lava flows. The porphyritic type occurs locally usually as dykes in the more compact varieties (andesites). A similar association occurs at Lambay and Portrane, and the general identity and mode of occurrence of the basic rocks of these localities, and of those on the west of the Leinster granite, suggest that all belong to the same geological period, namely, Baia, according to the recent work of Messrs. Gardiner and Reynolds.’ Though some interesting changes have been brought about in these older rocks by the granite, the present Paper is concerned only with one instance; having reference to some small outcrops in the neighbourhood of Donard (Co. Wicklow), noted at a and B on the accompanying sketch map of the district (p.570). Donard isa small village, some six miles south-east of Dunlavin ; and in the case of the outcrops just mentioned the results of both thermo- and dynamo- metamorphic action are well illustrated in the changes brought about in a porphyritic andesite developed here in some abundance. One outcrop of this rock occurs at Deerpark-hill (8), a little overa mile south of Donard, the other at Ballymooney-hill (a), about an 1 « Summary of Progress,’’ 1899, p. 177. 2 Journ. Roy. Geol. Soc. Ireland. vol. v., p. 57. 3 Quart. Journ. Geol. Soc., vol. liv., p. 147, 1898. O70 Scientific Proceedings, Royal Dublin Society. equal distance north of the same village. In the first-named locality the rock may be obtained in a practically unsheared condition, but at Ballymooney, where it occurs in greater quantity, it is every- where highly sheared. The direction of shearing in both cases is approximately parallel to the axis of the granite mass, 7.e. north- east and south-west, but a reference to the map below will explain how it is that the shearing has been apparently more intense in the northern than in the southern locality. At Deerpark a tongue of : [\ Schistase \\andesite |} Xx a icra O Uopan x x Va GRANITE x x chistose J% x x x Mere OG x andesite granite runs out from the main mass in a north-west direction, that is, across the general strike of the Ordovician slates, and at right an- gles also to the direction of shearing. On the ground this granite tongue forms a prominent rounded saddle-ridge, on the lower slopes of which occurs the porphyritic rock referred to. It is clear that, on the assumption that this granite mass resisted the shearing, a rock lying in such a position would be more protected from shearing effects than'one occurring in an exposed position, as is the case Srymour—WHetamorphism of a Porphyritic Andesite. 9571 with the rock at Ballymooney. Hence, while the latter is highly schistose, the rock sheltered by the granite ridge is comparatively speaking, unaltered. In this locality, therefore, the rock may be obtained in a practically unsheared state; but it is yet very far from being in its original condition, for it has been completely thermo-metamorphosed by the granite. In its unaltered condition the rock was undoubtedly identical with the “ Lambay por- phyry,”’ the well-known porphyritic andesite occurring on Lambay island and on the shore at Portrane. The thermo-metamorphism of an andesite of similar type has been described in detail by Messrs. Harker and Marr,! and the rocks near Donard have gone through similar stages of alteration. The final result has been a complete re-crystallization of the original constituents of the ground-mass which now consists chiefly — of a bronzy-brown mica, associated with a minutely crystalline mosaic of clear felspar and quartz only occasionally distinguishable from one another in thin sections under the microscope. Starting then with the Donard rock in this condition, its subsequent altera- tion by pressure may be readily traced in the field by the changes undergone by the porphyritic felspars, which stand out conspi- cuously on a weathered surface. Prior to any shearing effects these phenocrysts are seen to be arranged in an irregular manner (fig. 1, Pl. xxvr.), and form stumpy prisms of varying size up to a maximum of 1:5 x 1 x 0:5 cm. scattered singly or less often in glomero-porphyritic groups (fig. 1, Pl. xxvit.) throughout the rock. The crystals on a fresh fracture are rather brownish in colour owing to numerous secondary inclusions, but still show several parallel light reflecting bands due to repeated twinning. The first modifica- tion produced by pressure is to cause these plagioclases (andesine or labradorite) to arrange themselves in a direction with their longer axes approximately parallel to one another (fig. 2, Pl. xxvi.). They are in this condition not very much elongated, though their cross- sections have become somewhat flattened. The next stage con ists in the gradual drawing out of the crystals which become longer and longer (fig. 3, Pl. xxvit.), till finally they become leaf or torpedo- shaped, flattened lenticles up to 6 cm. or more long, about 1 cm. broad, and varying in thickness at various points from 0-1 to 1 mm. 1 Quart. Journ. Geol. Soe., vol. xlvii., pp. 293-300. 572 Scientific Proceedings, Royal Dublin Society. The length of one of these lenticles depends on whether it has resulted from the elongation of a single crystal, or of a glomero- porphyritic group, being naturally longer in the latter case. The final result is the production of a banded rock composed of alter- nating dark (biotite) and light (felspar) laminz which presents, on a minute scale, the characteristic structures of a banded gneiss (fig. 4, Pl. xxvit.) Under the microscope the first sign of the effects of pres- sure in the felspars is the production of strain shadows, which is followed by fracture and strain slip cleavage. A. continuance of the pressure results ina certain amount of granulation, after which the lengthening process goes on apparently by solution and recrys- tallization to the final stage. In this the original crystal of plagioclase is reduced toa granular mosaic the individual grains of which show little or no strain shadows, being largely re-crystal- lized material, consisting of water-clear quartz and felspar, with biotite, and some secondary muscovite. Accompanying these are secondary crystals of colourless epidote and zoisite. In this condition the ground only differs from the sheared crystals in the relative abundance of secondary biotite, and the original rock has been reduced to one consisting of practically uniform-sized grains, a rather characteristic structure of gneisses and schists. The biotites are all orientated parallel to the direction of shearing, except where they occur between the felspathic lenticles. In these positions they often stand in a direction at right angles to the direction of shear. It is very remarkable that in no instance are the ends of two adjoining sheared lenticles of original felspar welded together, so to speak, by the mashing action which the rock has undergone. ‘They are invariably separated by a thin film of the matrix (fig. 4, Pl. xxvit.), and nowhere, so far as can be seen, has any mechanical mixture of the felspar and the ground been produced, both maintaining their separate individualities to the end. ‘This seems to show that the rock at all times moved practi- cally as a solid, and never approached the molten condition. The ground of the rock, however, which started practically in the condition as regards texture to which the plagioclase pheno- crysts were eventually reduced, in turn produced new structures while these phenocrysts were being stretched out. The one most Srvmour—Wetamorphism of a Porphyritic Andesite. 573 noticeable is the tendency to form larger crystalline constituents, especially in the case of the biotite. A section of the rock in the final stage shows frequent knots or bunches of this mineral in the ground, the individual crystals of which are of much larger size than usual, and considerably larger than those of the ground at the expense of the smaller individuals of which they have been developed. The occurrence of larger biotite crystals in the late stage of the dynamic alteration of the Donard rock was noted by me in 1899', but its significance was not recognised till after reading recently a Paper by Van Hise’ dealing with metamor- phism. This author notes, in discussing re-crystallization, that, as the process of granulation goes on, a stage is reached beyond which the particles do not become more finely granulated, but a reverse process takes place, and instead of becoming smaller they become larger. He regards the coarsely crystalline, perfectly schis- tose rocks, nearly free from strain shadows as representing the most advanced stages of metamorphism. The age of the shearing movement which has effected the Donard rock above described is clearly contemporaneous with that of the intrusion of the Leinster granite. Professor Sollas? believes that the granite laccolite was injected in successive sheets part passu with the tolding of its Ordovician cover, and that this movement continued for some time, and was very slow. Evidence is adduced for this by the presence of fractured contact minerals (garnets) produced in the neighbouring slates surrounding the granite’ mass. Confirmatory evidence is afforded by the Donard rock, for the shearing has been evidently superimposed on a rock already meta- morphosed by contact with the granite. When it was slightly sheared, an intrusion of granite took place, veins from which (still found unsheared in the Deerpark area) traversed the basic rocks. Other veins of aplite have, however, been highly sheared in the northern locality (Ballymooney) due to further movement after their intrusion. Veins of quartz cutting the basic rocks are also sheared by the same movement and in the same direction, but it is uncertain whether these quartz veins are of granitic or earlier origin. 1<¢ Summary of Progress,’’ 1899, p. 178. # Bull. Geol. Soc, Am., vol. 9, 1898. 3 Proc. Geologists’ Assoc., vol. xiii., 1893. O74 Scientific Proceedings, Royal Dublin Society. Tn conclusion, a banded and perfectly crystalline gneiss appears on the foregoing evidence to be capable of being produced solely by “mass-dynamic” agencies, acting on anon-homogeneous rock, as one type of which we may regard the porphyritic andesite described in the present paper. EXPLANATION OF PLATES. PLATE XXVI. Ie ; 1.—Weathered surface (54 x 42 cms. approx.),! of the porphyritic andesite at Deerpark (8), showing irregular arrangement of the felspar phenocrysts in the right-hand top corner. Part of the rock is slightly sheared. _ 29.—Surface of rock (67 x 52 cms.) approx.) near the last, showing first signs of alteration by pressure in the general parallelism of the felspar crystals, A quartz vein, sheared by the same movement, is shown in the upper portion of the photograph. PLATE XXVII. Fie. 1.—Photo. of hand-specimen (18 x 8 ems.), showing glomero-por- phyritic arrangement of the felspar siystnals on weathered surface. 2.—Photo. of hand-specimen (8 x 4 cms.), showing flattened cross- sections of the felspars in an intermediate stage of elongation. 3.—Photo. of hand-specimen (11 x 7 ems.), showing appearance of the felspars in a direction parallel to that of elongation, and almost in the final stage of alteration. 4.—Photo. of part of hand-specimen (15 x 5 cms.), showing banded character of the schist produced by the effects of pressure and re-crystallization from the porphyritic andesite (fig. 1). 1 The dimensions given in brackets are those of the original specimens, or portions of specimens, shown in the photographs. 1575 J XLVIII. SOME RESULTS OF GLACIAL DRAINAGE ROUND MONT- PHLIER HILL, CO. DUBLIN. By W. B. WRIGHT, B.A. (Prares XXVIII. anp XXIX.) [ COMMUNICATED BY PROFESSOR J. JOLY, F.R.S., HON. SHC. R.D.S. | ‘ [Read June 18 ; Received for Publication Jun 20 ; Published SzpremBeEr 20, 1902. ] In many places on the northern slopes of the Dublin Mountains there occur curious deep valleys, which cut across the spurs of the hills, and which cannot be accounted for with the present topo- graphy. Their general character, moreover, is such as to suggest that they have been cut by running water at a period geologically not very remote ; and it is hence necessary to imagine some agency not only capable of modifying the ground sufficiently to cause such a flow of water, but also capable of being removed in the comparatively short time since elapsed. A very typical example, and one with many interesting associated phenomena, happened to come within the area allotted to me to survey during last summer, and I was hence enabled to examine it in detail. While seeking an explanation of these phenomena, my atten- tion was called to various papers in which similar gaps recently observed in other portions of the British Isles and in America were described, and the explanation adopted in these cases seemed to apply equally well in that which I am about to describe.’ In all these cases the gullies were explained either by the action of water ponded back against the hills by the ice-sheet, and 1 Hermann Leroy Fairchild: ‘‘ Glacial Lakes of Western New York.’’ Bulletin Geol. Soc. America, vol. vi., pp. 353-74. G. W. Lamplugh: ‘Annual Report of the Geological Survey and Museum of Practical Geology for the Year ending December 31, 1895. Appendix to the 43rd Report of the Department of Science and Art, p. 18. Brit. Assoc. for the Advance- ment of Science. The Isle of Man. An Appendix to the Handbook of 1896. Part ii., Geology, p. 179. Percy F. Kendall: ‘‘ On the Glacial Drainage of Yorkshire.’’ Rep. Brit. Assoc., 1899, Dover. Thomas L. Watson: ‘‘ Some High Levels in the Post-Glacial Development of the SCIEN. PROC. R.D.S., VOL. IX., PART. V. YG 576 Scientific Proceedings, Royal Dublin Society. draining directly across the ridges, as overflows from lakes held in between the ice margin and the bare land, or as having been cut by rivers flowing on the surface of the ice-sheet, just as the ridges emerged from it. Certain passages: were also brought to my notice by Mr. Lamplugh, which are of interest as showing that even the earlier local geologists took note of these gaps, and recognized the diff- culty of accounting for them. As early as 1811, in Stephens and Fitton’s Mineralogy of the Vicinity of Dublin' the following passage occurs :— “ At the foot of the mountains near this place” (7.e. Dundrum) ‘ig one of the fissures already mentioned as somewhat resembling the Scalp in structure, the course of which is from west to east, parallel to the face of the mountain.” There is also a descrip- tion of the Scalp, and the foot-note—“ Fissures similar to the Scalp though on a much smaller scale occur in other parts of the granite tract near Dublin, as at the foot of the mountains above Dundrum, and elsewhere. The mode of their formation offers an interesting subject of inquiry.” John Scouler, in 1838, in a paper ‘“‘On the Raised Beaches near Dublin,” has the following passage :— “There is also another very curious ahencmnemon which, I think, may be associated with the preceding one” (@.e. the high level shelly gravels). ‘‘ Besides the valleys, whose streams dis- charge themselves into the Bay of Dublin, and which we have seen have all been formerly blocked up by transported matter, there is another set of valleys, or more correctly ravines, which have a general easterly and westerly direction, and are conse- quently nearly at right angles to the valleys containing trans- ported matter, and these ravines are all destitute of any beds of gravel or detritus carried for a distance. The valleys or gaps which possess this negative character are the Scalp, the Dargle, Finger Lakes of New York. Appendix B. Report of the Director of the New York State Museum, 1899.’’ Review in Journal of Geology. J. E. Wilson: ‘‘On a Glacial ‘ Extra-Morainic’ Lake occupying the Valley of the Bradford Beck.’’ Rep. Brit. Assoc., 1900, Bradford, p. 755. Albert Jowett, m.sc., and Herbert B. Muff: ‘‘ A Preliminary Note on the Glaciation of the Keighly and Bradford District.” Rep. Brit. Assoc., 1900, Bradford, p. 756. 1 ¢¢ Notes on the Mineralogy of part of the Vicinity of Dublin, taken principally from the Papers of the late Rey. Walter Stephens, a.m.,’’ by William Fitton. London, 1811. Wricut— Glacial Drainage round Montpelier Hill, Co. Dublin. 577 and the Glen of the Downs; the first cuts across both the granite axis and the strata of micaceous schist which recline against it ; the second is nearly parallel to the first, and the third has cut through strata of quartz-rock. All these ravines contain vast detached blocks of the adjacent rocks, granite in the first, and quartz in the second. Now it appears probable that the forma- tion of these ravines was subsequent to the deposition of the shelly gravels; for had they existed along with the valleys containing transported matter, it is difficult to conceive how they should now be so thoroughly destitute of all vestiges of it, especially when it is remembered, ‘that none of these ravines ever possessed any stream which could carry off their contents. As many of the shelly gravels occupy a higher level than these valleys, it is incon- ceivable if both orders of valleys were contemporary, and both equally under the water, as must have been the case, upon what principle of selection one set were the receptacles of transported matter while the others escaped? It therefore appears probable that the ravines were of later origin and are with the shattered blocks which are still in situ, the indications of the nature of that force which has elevated the shelly beds into their actual position.’” The Rev. Maxwell Close’ also drew attention to these curious valleys, and recognized that they were directly connected with the other glacial phenomena of the district, suggesting that they might have been formed by the excavating action of ice. He remarked on “the straightness and better definition of those valleys on the east side of the mountain range; the fact that their cols are often situated to the west of what seems to have been the original position of the watersheds of the passes: the last two peculiarities are precisely what might be induced by a glacial flood of sufficient denuding efficacy, coming from the north-west, partly dammed up by the long mountain barrier, and pouring over the crest thereof down the steeper slope of its lee-side.”’ The transverse gully, which is the most striking feature in the small area here described, trenches completely across the lowest 1 «* Account of Certain Elevated Hills of Gravel, containing Marine Shells, which occur in the County of Dublin,’’ by John Scouler, Journ. Geol. Soc., Dublin, vol. i., p. 266. 2 Rey. Maxwell H. Close, ‘‘ Notes on the General Glaciation of the Rocks in the Neighbourhood of Dublin,’? Journ. Roy. Geol. Soc. of Ireland, vol. i., p. 3, 1864. 578 Scientific Proceedings, Royal Dublin Society. point of the ridge connecting Montpelier Hill with the main mass of the Dublin Mountains to the south. Small streams enter it near the ends, and flow east and west from it, but at its summit it is quite dry, and it is this absence of any adequate eroding agent which is the most remarkable characteristic of this and other similar gaps. The form of the ground at both ends of the pass indicates that, previous to the Glacial Period, shallow valleys had been excavated in the hillside on both slopes of the ridge, and atmospheric erosion, aided by the wash of rain, seems to have lowered in some degree the narrow portion of the ridge separating their head waters. In the shallow depression thus formed, the deep notch has been cut which now unites the heads of the two valleys. It is about 500 yards long, and has sides from 90 to 100 feet high, sloping at angles varying from 25 to 35 degrees, composed in the western part of slate and in the eastern part of granite, the gorge traversing the junction of the two formations, and appa- rently having no reference to the solid structure. The highest point of the floor is 1035 feet above the Ordnance datum line, and about 100 feet higher than the tops of the lower mounds mentioned below as occurring at the mouth of the Piperstown Valley. ‘The form of the floor is so irregular, that no deduction can be made from its slope as to the direction in which the eroding water flowed. This is principally owing to the large amount of talus which has fallen in from the sides. The pass proper is continued in an easterly direction as a comparatively shallow but fairly steep- sided gully, partly excavated in drift and partly in granite, run- ning down the slope into the Killakee Valley, and forming a trench in one side of the shallow depression which formerly existed here. The stream which flows from the west end of the gap pours into a slightly larger stream coming from the south, the valley of which, at the point of junction, turns sharply to the west and opens out into Glenasmole. It is this valley, in which the village of Piperstown lies, that contains the most remarkable deposit of gravels in the district. From the mouth of the Piperstown Valley westward there stretches away the smooth gently-sloping plain of boulder-clay which fills up the lower part of Glenasmole. The gravels set in in a fairly straight line across the mouth of the valley and appear to lie on the boulder clay. Immediately to the east of this line they rise suddenly from the plain into two very “de oY} MOAT SIIGop OT}IULAS Fo spunow oj Orv OSTVaIay ‘(81g -d 9a8) AynS Surdojs v sv 4sve ponuryuoo st pur ‘spue redoad ssvd oy} @ yV dn petip Mou yoTWeerys B WoAZ oM0 [erAnT[e Aury v st 4 qruTUINs OY} FV “my} Morz snTe} oy} Aq poster ATqvreprtsuoo uoeq ATquqord svy LOOM oy} pure ‘SopIs UWA9.1}S-1ep[noq doo}s YjIM MOIIVU ST II Q 0} gf MOTT “qSoM SMOP TOIT s10}U9 Wree.}s T[eUs v Ff Ivou pur ‘opr AyaTEF st ssud oy} Ff 0} 0 MOTT "9]BOS [BOTJIOA poyeroSSexe uv YIM (z) ‘o[vos ont} B 0} (T) UMoOYs ssed oY} Jo 100H oy} BuoTe worpeg—'s “S1q Q no g ” T2A2], 0007 “B) INS) MSM Q k ey} r) ‘ureyo 0} ‘uI-F ‘aTeos enzy, . ‘a[Ros ond], “qIuItUNS 4B Sssvd JO UOT}DES OSIOASUBIT.—"Z “OI “TILL torjadyuoy ssortoe wory9eg—"T “O17 "]2A2] ,008° 580 Scientific Proceedings, Royal Dublin Society. remarkable mounds, between which the stream flows. Where’ these mounds abut upon the hills, they, ike the boulder-clay, are covered over to a certain extent with local wash from the slopes above. The gravels themselves are well stratified and waterworn, and consist, for the most part, of limestone, but also contain a considerable proportion of granite, slate and greenstone. No shell fragments have been found in them, but as they are known to occur in similar gravels at Annmount, about 400 yards further westward, this is owing most likely to the smallness of the ex- posures, which hardly reach below the weathered surface. When traced eastward up the Piperstown valley these gravels form a series of mounds, rising gradualiy on the slopes as we ascend the valley. They thin out in its head and on the moor to the south of Montpelier Hill into a mere sprinkling of pebbles on the rocky surface. Hven here, however, they rise occasionally into small mounds. ‘They extend thus in places nearly up to the 1250 feet contour, the upper limit appearing to be indicated here and there by a faint rise of the surface. > ~ Eze me — ee > Ss > 2 SO in an wn QP & Ss, — 2 Sah iN EN a Ry Tee SAR Sh SS Se a) SS = aa Fa OS TS ta 85 “Sh 5 py Ry ANA DIAGRAM ILLUSTRATING FAULT DYKE OVERTHRUSTS. ‘OLY ‘MOOTO NOILOW WYOAIND “Al 9¥8 1d *PPUCH Fo SST en rr ew ee eee Odi 42 YOIMUaID g—-- = 5 42219 Peltes ¢ 4 So apa Ea pur Aiaqyeg of YY Shyo9 Shoe a> t- + | Y072 (pozu2s) pln pyozey "YOINUIDLD Udy 4 H 7 7 yf C) | “Ou suaceno yoo tos Aozayyy PUPLNIYDIN ACL ADB] [2 ll JW Aoyeg a is ‘ , “gor quo: . PIM ou OUAL CULT YoIMUaaWD Paeee 19015 poiees Olg-=1- g | y : af ; i... ' pDizo0p wo SS enn nnnee ne nnn nwa - nen ~~ fe worm ennnn-e Seencwee-e-- bisssessesqaccosezccces--“-- 5 =, eles ches {y20)2 Linyngrnsrp.to pauyu0p : 1 1 ' ' ' ‘ ’ 1 ‘ ' 1 ' ' 1 ’ 1 ‘ ! ! 1! ' 1 1 1 i ‘ AONION IID Uj Pazzaudor aq on sryz, i) x : EEG tb 2 Pei] Goyeg PLoS ti Aroy32g 0114 our yea ’ 1 1 ' 1 ‘ ‘ ‘ ‘ i 1 ‘ ' ' ‘ ‘ 1 1 1 1 i] 1 1 ' ’ 1 1 i 1 1 ' 1 1 1 i) ‘ { 1 1 1 ' ' 1 iy ' 0 1 1 , 1 ‘ ‘ ‘ 1 ! ‘ ! ' ‘ 5 i) 1 1 ‘ 1 ' 1 ' 1 ‘ 1 1 1 t 1 1 1 1 y 4 ' ! { 1 1 1 ' "S10 ghP oni297 7 10 onpuinauer Aq syooza “oyjo burarp sop Su0rpzsuuvd AUD popumiolog Mou stygug@ zipuids aynuzu sup sopuurus tod soupy 813 Mia sgdp yoga wopou wuieppp ‘| “JOA “ON “say "d0dd * Va , * : / ‘ re s t ; 1 f. é ch - Spar > persed one er d es whe ee i : : : i cs ; 5 ee ae ee - - : } Ne Z ate Bag : = 3 7 we H 2 Sie PEA ; PB es = ' ts >; : % oe ES a SS a Proc. R.D.S., N.S., Vol. IX. Plate V. UNIFORM MOTION CLOCK, Erc, ne, M he \ 4 ie’ \ y) i t E , 4 ‘ fase Z | ( Reta | rn YMVIIId WOO 40 NOIWVWWHOS GNV “VS4JW 4H NO JOVNIVEYC 40 LNSWSO0NSWWOO ONIMOHS VYVOHVONHIHO — VONVTIG Vidsnd V] aUIp3 yal “2uiye4y e QUBB sw . “8p “G'd y PERERA RS ge Srnec “TEN 1®Tq 7 Ta) TOA “oN oe ral Sap DOG] id OO@Z NOILVASIQ VONVYHYG 3G OLITO WOH4S “YSAIY ANDINA AHL 40 VONVUYVG GNVYO {WIpQ ‘yat] ‘auiysay auele 4s y IIA 29PId ‘XT TPA SNS GY 9%d ” “YHYONOS NI INHVNIHOOG NOs NYVOWOA sil Olsltelsi9) allt 20 el@jL SUlpy “yar ‘auiyssg avelJe4sW lap “d'a yo INA 93"1d ‘XI TPA “SN “S “'Y (9% Lar es gph) Pte ree Pe a Wipz ya] 9U14sg g auelse ys iy AL EBA ikal (ULI ake! SOW WUNA alist AlO}als| NO) SOMONE) cSlelitsltsh/ (| Gat{d| shield “18P aay 1 (ANS) NE ShG@ Sear ‘SSVENWEIA JL IWIN, INSIMAJE ILIFIS)IRSl alInUL IL shohwtslelaul S)shv/q) ‘G39 43y¥V1 G10 HONOYHL TSANNVHO YSAIY auIyS4q 7 BUEl4e43 ep day ‘X 99% 1d . So SN Se Ghse0ric “SSYUVENL YVAN NOISSIW WOUS NavWVL SONVISIG NI SS0VYuSL GNY WOOE Haleauvea SGdse 4yvV1 GiO 40 SS9qa dagoug jUipy “yal ‘aulyssg py auese yoy “12P ‘0°0'M IDK SEN fal “YL TAS N “SCS 90d OS ee NY aSOf NVS YVAN JSGIS NIVINNOW WOYS YSAIY SV I1NIdOlvq pa “yay ‘Susys4y x gue|4P45)) UNC SBE Ala : MOON SONS Ole Peer ATID TI Wel WIS) tal aiIN| SHC JUS/at Sir NONI ASTI SIKU eli GINY SSOSOY WaltA alors) acl OY SNRLL sO NONYWS SUIPZ Yat] ‘2u1y4s49 y auelse sy IX 99° XT SN Ss @ aera o i —S eee ee Plate XIV. MtFarlane & Erskine, Lith = del Spirito C y Piri Cerro de Metate Tp SO WF ie FRO le wa bieta Mead ie MSFarlane & Erskine. Lith Edin Realito r ‘, ev ES Nee : ; ; Z 7 NX ER \ A iS aes fe — g = n © > AC 4 - —— 5 | =e is ee ; . a . = — “. Cordon \del Spirito fancho Vie cee any e- } 7 Z ql = ‘ Pre. . | Gerro de Babielio r =e = C. de Rosario ~~ | P oe | < = ! OS / C.de Gracilis = Rifts z = ————— et es Cerroade Potrero - ‘ ‘a Z j : > Ss iy y = y Cordon de Santa Rita Se y SS freee Gace Ge (es Wn Mdeves ‘ r SS 3 P aX L,/ = Wagers de Metate / { \ aaa . c/n — ; , 29 ol ii / a Oe aa Cerro Prieto Jiet [Pita |, / / Cerro, Arroyo de (Oso iy / | Arroyo de Bacaba EAST. | SOUTH. WEST. uN ORBEA sere EL OdJ/7 0 | Elevation 6630 feet. | Plate XV. Pineclad. Mesa 26°45"-0" 26°45 0" — = Ta Alamos mreceike bss. N.S. Vol. 1X. TEMOrIS 5207 Plate XV. Pineclad \ Taquina Cerra de Sara/bo ou ‘olorada mot Oy Oe Sa Ue yy Up. y oS Ad Man Ui; >< oe Rit a5 € Be TNS ~ xX Ke Vertes fol Lop iz < 5 we Z; 7 as é “ if Hy Thi nGuaze| H as Sh \< Acer ae it * ‘osario me =< OS SEX la Sata ae Be ond? d 1m : Tres Cruces \\ terra dek|\ ie Pa 7 ‘al mes é yy SS erro de ~Babiella ~ ) atl Gaia LIK Banh Ty» + wns | —— el eee wamachia Oi tie de Canciz Huasa gota Cerro Colorado Cerrocahui 1% i ity 2miles 6038 YX aaa Shy te Prieto e Cee Re iS \i/ w Pees me, Nos Otates® toepe ree wares y de L re hu we niry 7 a5 us OS “ . 4 g% ti \ Cerne SS wi ana San Tg) Wat Sv \ Cerro de xfs ry » ToS Yy SZ set Rea/ito’~ N= er = eu! I \\ ie Ze i. OF THE SIER p ‘ WESTERN MEXICO BY K. Dryden Doyle. 8 9 10 Miles Scale, one inch ta-F Miles AThereto pe Pineclad. Mesa 252% V bbe aS 2523 I) Cerro de gm) ) xe San José”! >A WTP Ki rd J 7 orpitill yliay, San Migifa TL) Ni ry % SS on IS VUipy, Mm SL pe Ns Ii( ‘Morelos Aifarinne & raking, Lish Edin” PARTS BY VOLUME OF CARBONIC ANHYDRIDE IN 10,000 oF Ar. rilate AVI. 7 F 3:8 oy PETERMANN& GRAFTIAU. Gembloux.) 6 | SPRING & ROLAND. (Leege.) Fr. FARSKY. (Tabor.) g 3 __1874-_| F/TTBOGEN & HASSELBARTH. ar ( Dah me.) /872 ro RISLER. (Catéves.) 0 Fee se ius ee U. REISET. (Déeppe.) 9 O7/ y, E.v. FREY. (Dorpat.) 4é —IL a [See 2-4 NOVEMBER DECEMBER JANUARY ies. WosaiRinceacmn PL. x st ni Gein : x Ste: — EEE oc. R.D.S,N.S, Vol.IX. Plate XVI. j sa SEASONAL VARIATIONS OF ATMOSPHERIC CARBONIC ANHYDRIDE. 3 Ss Saee ‘8 yea i PETERMANN& GRAFTIAU. 18h \ : (Gemblovr) : PETERMANN& GRAFTIAU. \ (Gembloux.) ‘ K / 6 \ + ~ | i 1-6 ‘ C2 LEVY. (Me is.) |1879. : . Ne Re A.LEVY. (Montsouris.) }1879 e evy_1a7e.!_ ‘| SPRING & ROLAND. aa —-f = (Lcege.) d \ Zz \ i a aa Tas / 5 & \ A \ 2 j A . % ; 1874._| F/TTBOGEN & HASSELBARTH. (Oahme.) ———e : Q NE a @ —— ! f= (Oahme.) ia} SS \ Fi 2 \ | : 2 g A.LEVY. (Montsouris.) es \ ; / z e ; } |! et = > Zz Se oe \ : Lee w Sy Tas a IS ne, 789 742 N ea Z, A.LEVY.(Montsourés.) \/ea, \ia73\.-—---|— oe. % ZS NY La oul RISLER. (CaLeves.) — -|—=~ er 690 —~Es0. S Pali he’ j S224 RISLER. (Cate A ‘ ot? eee : ec a <\ BD . (Caleves.) F.SCHULZE. (Rostock) Woo a= 7 =e === = ie = =I PETERMANN & GRAFTIAU fy FSCHULZE. (Rostock. —\e see: — ==. se ie “ = von 1h-4 : QO ALLEVY./Montsouris.) Ke, \—-- ENS a Ro ee We LSS BENG i : (GembLoux.) © ci = = SDe Zz ‘ ac oD. i f] RE/SET. (Dieppe.) \a7®S—-\-- S > 3 Sen N OB eof : is ALEVY.(Montaouris.) 6 1885) &5 oe 1978 1912 Se > S £870, 4a SAN eg) yp REISET. (Dieppe.) A <3 ; : 18s <2 Sa ~< 89. Ye ¢ = QE ‘ = A 7 2 5 eZ o. ~~. Ss a . 3 G FP EZ ( P S ALEVY.(Montsouris.) | : > Te? Beas iB F/ we Ni ade \. y, NG een ane 1870: oa Kh : . fi As , oe BON F.SCHULZE. (Rostock, Z. ~ ayy ~ 7 = grea meg Soceogbaressss A =i 7 o t 7 Xe \ 7 E.v. FREY. (Dorpa.t.) \ e % A : A.LEVY. (Montsouris.) . \ Y . SS i \ UY / J 6 Zz S wa : 7 | 6 7 Daly? N W. \ A SO We \ ye Pa ~N. 7 : , \ A ~ a SZ a a Nec SZ il 5 | | 24 1 | = zips SS « « > « kK a 5 a uw z x 3 &S a % = fs) a Q w SS > a = = 5 " cs x 2 g re) L © w 4 = % x a KR > ° = = uy RS a s 2 2 3 ry S 3 u x >) w = < . = x a S) } = 9 2) 4 Towns. Sea-side localties. _._-..— Inland country localities. Went, Newman lith po st i 4 A f < i ad a h Plate XVII. TEMPERATURE. 77-1879.) SS | ye 1 =! | d ig * tg i q +9 u S < S) S w i tS) © iS) ty © = Q West, Newman lith. Proe.R.D.S,N.5, Vol. IX. THE AMOUNT OF CARBONIC ANHYDRI DE IN GROUND AIR IN RELATION TO TEMPERATURE. ieTewee 2A (CALCULATED FROM Von FopOR’S RESULTS AT Bupa-PESTH DURING THE PERIOD 1877-1879.) CaRBoNIc ANHYDRIDE IN 1 000 oF AiR, ALSO CENTIGRADE.) TEMPERATURE ( OF VOLUME ax PARTS BY 50 40 HL JANUARY FEBRUARY MARCH APRIL MAY JUNE JULY AUGUST SEPTEMBER Amount of Carbome Anhydride in Ground Air at a depth of | metre. » ) n aD) ‘Temperature of the Atmosphere. ” ” » ”» ” ” ” ” » » Ground at a depth of 1 metre. ” » ” » 4.metres. » ) 4metres. HL OCTOBER NOVEMBER , , , DECEMBER West, Newman lith. mal Ke oO 465) zB jay @ ae a ar = iS) enol | | | YIIWIOIO West, Newman lith YAIAGNAFIAON YFHFOLIO I Bia seat Kany Proc. R.D.8,N.S,Vol.IX, ATMOSPHERIC CARBONIC ANHYDRIDE IN RELATION TO GROUND AIR Plate XVIIL TEMPERATURE AND ATMOSPHERIC PRECIPITATES. (CaLcuLarEp FROM VON FODOR'S RESULTS AT BupDA-PESTH DURING THE PERIOD 187 ~J 1 HW ioe) ~J co} iv x & c - > &K Wy C Wy ~ a & 3 x 2 y » Q Q z 2 x > S x = z x Pe) my S u uj 5 x & a x > > S k z x ° 2 Ss < = S > a 8 S uy m = SS Ww 8 = Q < my ui S W West, Newman lth Carbonic Anhydride in parts per 10,000 in air above ground level. ear e Sari y ” ” » » » ” » » at » ” — i . en » 1,000 , ground air from a depth of 1 metre. F Sa — Rain, Snow or Hail (Hach unit in the vertical cohmmn corresponds with 50 mm. of rain.) ------.... Temperature of the air (Hach umt in the vertical column corresponds with 10°C. ) Proc. R.D.S:,N.S.,Vol. 1X. Plate XIX. G.G. delt. M‘Farlane & Erskine, Lith. Edin? PIAS, IBID Son WlaSen NIG IOS PENS DOK, View of quarry opened near Drumboy. ‘The vogesite dyke forms a dark mass crossing the foreground, and cutting the structural planes of the paler schists, which appear above. Plate XXII. (to face p. 364.) 4.0 4,30 70° End of Lelipse = 60° ee 50° e 40. / 130? 420° 10° 4,0 4.30 4.50 End of Lclipse —E—————EEE aling Scarcely any Wind Wind rising IPAs IRNGIDOS G5 ING ay WANE IDR ake, hr.30 mins 60) 2.0 Lelipse begins Ill. BLACK BULB 4.0 Plate XXII. (to face p. 364.) 4.30 End. of Eelipse 40 30 Middle N of Lclipse WHITE BULB 10 Li clipse begins Lind of Eelipse LEchpse begins Wind rather strong Clouds Clouds Ce el Middle of Eclipse Middle of Eclipse <—_———_ Wind falling Scarcely any Wind End of Eclipse Wind rising 30” IPYFOOs IRID)sS05 Io Soy WOll, IDX. a 1.15 The Expansion of Silica with Rise of Tem ee ae 1.10 al 100° _| 200° 300° 400° 500° rature Plate XXII. enlie! LT 7 zal | = == - : EEE — -== E Ee =A isc (se ok Q° 1500° 2000° Proc, R.D:S:, N-s., Vol. LX. Plate SS. ieee seers Sas mel | | Ee a SdUSSGSS00SSS000eeee 2” _ eee | ie aa The Expansion of Silica with Rise of Temperature AL ; ay | ial Halal +++— |] {4+ — se ele Ls ice LY mer I i | i {eo =| 3 lhe i 5 | (al all ee = | — ea esd * Z al ws [a Hel L | L i io) | = at ial all Bo | | eae Eile | fica eS || i bal ca lil a eaie : i ci is il oF a de sills El 4 F rite, (' Zs > Lp pe | LL I pa a] 1.05 aia oe oe E | ay SPEECH Gb eer See EAE Eee s ==! quis = is ozs |—|- ——+ 1 - er A I s{ | e ne Lo | | a aigiciee aa 3 IPOS 1.00 1000° 100° 200° 300° 400° 500° 1500° 2000° IPIPOC, IRoID)5So5 INoSon WOlls 2s. 680 640 600 560 500° Temperature (cent) }- 1001 Plate XXIII. | rT “N\ a amu Hl .