April 14, 1 88 7] 



NA TURE 



575 



It concludes with a hope that the velocity of sound in a sub- 

 stance near the critical point may be investigated, in order that 

 we may know the two specific heats under these exceptional 

 circumstances. 



Physical Society, March 26.— Prof. Balfour Stewart, 

 President, in the chair. — The following paper was read : — On 

 the production, preparation, and properties of the finest fibres, 

 by Mr. C. V. Boys. The inquiry into the prjduction and pro- 

 perties of fibres was suggested by the experiments of Messrs. 

 Gibson and Gregory on the tenacity of spun gla^s, described 

 before the Society on February 12, and the necessity of using 

 such fibres in experiments on which Prof. Riicker and the 

 author are engaged. The various methods of producing organic 

 fibres such as silk, cobweb, iSrc, and the mineral fibres, volcanic 

 glass, slag wool, and spun glass, were referred to, and experi- 

 ments shown in which masses of fibres of sealing-wax or Canada 

 balsam were produced by electrifying the melted substance. In 

 producing very fine glass fibres, the author finds it best to use 

 very small quantities at high temperatures, and the velocity of 

 separation should be as great as possible. The oxyhydrogen 

 jet is used to attain the high temperature, and several methods 

 of obtaining a great velocity have been devised. The best 

 results obtained are given by a cross-bow and straw arrow, to 

 the tail of which a thin rod of the substance to be drawn is 

 cemented. Fine is used for the bow. because the ratio of its 

 elasticity to its density (on which the velocity attainable 

 depends) is great. The free end of the rod is held between the 

 fingers, and when the middle pirt has been heated to the required 

 temperature the string of the cross-bow is suddenly released, 

 thus projecting the arrow with great velocity and drawing out a 

 long fine fibre. By this means fibres of glass less than i/lo,oo3 

 of an inch in diameter can be made. The author has also ex- 

 perimented on many minerals, such as quartz, sapphire, ruby, 

 garnet, feldsp.ar, fluor-spar, augite, emerald, &c., with more or 

 less success. Ruby, sapphire, and fluor-spar cannot well be 

 drawn into fibres by this process, but quartz, a,ugite, and feld- 

 spar give very satisfactory results. Garnet, when treated at low 

 temperatures, yields fibres exhibiting the most beautiful colours. 

 .Some very interesting results have been obtained with quartz, 

 from which fibres less than 1/100,000 of an inch in diameter 

 have been obtained. It cannot be drawn directly from the 

 . crystal, but has to be slowly heated, fused, and cast in a thin 

 rod, which rod is attached to the arrow as previously described. 

 Quartz fibre exhibits remarkable properties, as it seems to be 

 free from torsional fatigue, so evident in glass and metallic 

 fibres, and on this account is most valuable for instruments 

 requiring torsional control. The tenacity of such fibres is about 

 fifty tons on the square inch. In the experiments on the fatigue 

 of fibres great difficulty was experienced in obtaining a cement 

 magnetically neutral, and sealing-wax was found the most suit- 

 able. An experiment was performed illustrating the fatigue of 

 glass fibres under torsion, and diagrams exhibited showing that 

 the effect of annealing them is to reduce the sub-permanent 

 deformation to about i/io its original amount under similar 

 conditions. Annealing quartz fibres does not improve their 

 torsional properties, and renders them rotten. Besides the use 

 of quartz for torsional measurements, the, author believes that 

 quartz thermometers would be free from the change of zero so 

 annoying in glass ones. He exhibited an annealed glass spiral 

 capable of weighing a millionth of a grain fairly accurately, and 

 also a diffraction grating made by placing the fine fibres side by 

 side in the threads of a fine screws. Gratings so made give 

 banded spectra of white light. The author regretted that his 

 paper was so incomplete, but thought the results already obtained 

 would be of interest to the Society. Prof W. G. Adams con- 

 gratulated the author on his most interesting paper, and con- 

 sidered the results to be of great importance. He believed the 

 banded spectra exhibited by the grating were probably due to 

 internal reflection within the fibres. Mr. Cunyngham .asked 

 whether the glass mirror used in the torsional experiments was 

 magnetic, to which the author replied that this was probable, 

 but even this assumption did not explain all the pecuharities 

 observed. — A paper by Prof Pickering was postponed till the 

 ne.xt meeting, on April 23. 



Edinburgh 



Scottish Meteorological Society, March 30. —Half-Yearly 

 Meeting. — Mr. John Murr.ny in the chair.— It was reported 

 that four new stations had been recently added, viz., Aberlour, 

 Oban, and .■\ilsa Craig and Oxcar Lighthouses ; and an arrange- 

 ment had been entered into with the Meteorological Council by 



wlilch daily observations of temperature and rainfall are trans- 

 mitted for the Weekly Weather Report issued by the Council for 

 agricultural and sanitary purposes from the Society's stations at 

 Lairg, Glencarron, Fort Augustus, Braemar, Ochtertyre, March- 

 mont, and Glenlee. Messrs. R. M. Smith, John Murray, and 

 J. Y. Buchanan were re-elected members of the Council. The 

 work of collecting and discussing the sea temperatures round 

 the .Scottish coast, for wTiich a grant of 50/. has been obtained 

 from the Government Grant Committee, has been transferred to 

 Mr. H. N. Dickson. The report from the Council enters some- 

 what in detail into the physical and biological work carried on 

 at the Scottish Marine Station. Six trips have been made since 

 July by the Medusa in the Firth of Clyde and connected 

 lochs, during which o'iservations of sea temperatures were 

 taken at all depths from the surface to the bottom, special 

 attention being directed to the further investigation of the 

 remarkable and unexpected distribution of temperature occurring 

 in this part of the ocean at certain seasons, as disclosed during 

 previous trips of the Medina. Dredging was also vigorously 

 prosecuted, and all the specimens obtained have been determined, 

 their anatomy investigated, and the results prepared for pub- 

 lication by the staff of the Scottish Marine Station. This 

 Station continues to be largely taken advantage of by biologists, 

 for whom tables are provided in the laboratory free of charge, 

 for prosecuting their zoological researches. As regards the Ben 

 Nevis Observatory, it was reported that the subscriptions raised 

 since the commencement of the present year for clearing off the 

 debt and founding a low-level station of the first order at Fort 

 William now amounted to 8221'., thus bringing up the amount 

 contributed by the public since the establishment of thp 

 Observatory in 1883 to nearly Sooo/. — An address was then 

 delivered by the Hon. Ralph Abercromby, at the request of the 

 Coimcil, on modern developments of cloud knowledge, with 

 lime-light illustrations of clouds from all parts of the world. It 

 was shown that clouds were everywhere the same, and that the 

 different forms of clouds which he had exhibited from all regions 

 of the globe could be seen in Scotland. A modification of the 

 present classification of clouds which has been proposed by Prof. 

 Hildebrandsson, of Upsala, and himself, was explained and 

 illustrated. He then dealt successively with the structure of 

 clouds and their height, the atmospheric conditions concerned in 

 the formation of the different kinds of clouds, the remarkable 

 results to which cloud-motions led as regards the nature of 

 cyclones and anticyclones, the forecasting value of clouds, and 

 finally the necessity of attending, in all efforts to interpret the 

 indications of clouds, not merely to their forms, but .also to their 

 surroundings. In moving a vote of thanks to the lecturer, 

 Prof. Chrystal took occasion to refer to the great beauty of the 

 photographs shown by the lime-light, which were highly 

 appreciated by a large and influential audience. 



Paris 

 Academy of Sciences, April 4. — M. Janssen, President, 

 in the chair. — Researches on certain phenomena connected with 

 the aberration of light, by M. Fizeau. The paper deals chiefly 

 with the nature of the phenomena that may be produced in the 

 reflection of a pencil of light on the surface of a mirror, assum- 

 ing this mirror to be endowed with a velocity comparable to that 

 of light. — Stroboscopic method for comparing the duration of 

 vibration of two diapasons, or that of the oscillation of two 

 pendulums, by M. Lippmann. A description is given of a very 

 accurate process of making these comparisons derived from the 

 stroboscopic method. — On the central calm in cyclonic storms, by 

 ^L H. Faye. This central stillness is found to be present in all 

 tropical cyclones, persisting even beyond the 50' latitude, but 

 becoming modified according as the storm approaches the 

 Pole without ever disappearing altogether. — On various 

 effects of irritation in the throat, and especially on loss of 

 sensibility and sudden death, by M. Brown- Sequard. 

 Numerous experiments tend to show that the skin of the 

 throat possesses, like the larynx, but to a less degree, the 

 power of arresting sensibility ; also that the larynx, the trachea, 

 and also, perhaps, the cuticle covering them, possess the 

 power of causing death under a mechanical irritation in the 

 same way as the rachidian bulb. — On the seismic pheno- 

 mena of February 1887, by M. Ch. V. Zenger. A parallelism 

 is suggested between these disturbances and atmospheric, elec- 

 tric, and magnetic phenomena and volcanic eruptions so often 

 occurring simultaneously. — Rectification of right, unicursal, 

 circular cubics by means of the elliptical integrals, by M. G. de 

 Longchamps. In supplement to his recent note, the author 



