April 2^, 1878] 



NATURE 



519 



&c. — Notes on the geology of Japan, by J. G. H. Godfrey, 

 F.G.S. 



Physical Society, March 16. — Prof. W. G. Adams, pre- 

 sident, in the chair. — A special general meeting was held for 

 the election, as an ex officio honorary member of the Society, of 

 the President of the Physical Society of Paris. — The following 

 candidates were then elected Members of the Society :— J. S. 

 Bergheim, W. M. Hicks, M.A,, Dr. J. Hopkinson, M.A., 

 D.Sc, Miss E, Prance, and T. Wills. — The Secretary read a 

 paper by Mr. W. J. Millar, C.E. on the transmission of vocal 

 and other sounds by wires. The author was led, mainly by a 

 consideration of the manner in which sounds are conveyed 

 through walls and partitions, to make an extensive series of 

 experiments on this subject, from which he concludes that con. 

 versation can be carried on at considerable distances by simply 

 employing stretched wires provided with suitable vibrating discs. 

 In oae experiment two copper wires were attached to points on 

 a telegraph wire 150 yards apart, and breathing, singing, &c., 

 were distinctly audible ; by stretched wires extending through a 

 house and provided with mouth- and ear-pieces in the several 

 rooms, conversation could be carried on without difficulty. The 

 materials employed for terminals were very varied, and the 

 vibrating disc, whether metal, wood, or india-rubber, &c., was 

 generally formed as a drum-head, the wire being fastened at its 

 centre. The volume of sound appears to be greater with a 

 heavy wire, but in all cases it requires to be stretched. — The 

 President referred to the experiments of Wheatstone on the con- 

 duction of sound by vibrating bodies, especially |long wooden 

 rods. He mentioned that in ^1856 a performance was given at 

 the Polytechnic at which numerous experiments connected with 

 such conduction were exhibited. Some years ago M. Cornu, in 

 conjunction with M. Mercadier, made experiments which showed 

 that vibrations can be transmitted along a copper wire and ren- 

 dered visible at the distant end on a rotating blackened drum. 

 The free end of the wire was attached to a piece of copperfoil fixed 

 at its base and provided with a point which left a clear trace on 

 the drum when the distant end was'^attached to, say, a vibrating 

 tuning-fork. By connecting such an arrangement with different 

 instruments and varying the, players also, M. Cornu has ascer- 

 tained the form and extent of vibration corresponding to each. 

 The arrangement adopted by him was exhibited by Prof. Adams, 

 and in conclusion he referred to a passage in Hooke's " Micro- 

 graphia," which clearly showed that he was aware of the facility 

 with which sounds can be transmitted by solid bodies. — Mr. W. 

 H. Preece described some experiments made in September of last 

 year, by Mr. A. W. Heaviside and Mr. Nixon at Newcastle-on- 

 Tyne on this subject, from which they conclude that the method 

 might certainly be applied with success to the transmission of 

 speech within a building. They find that a No. 4 wire gives 

 the best results. The terminals were wooden discs about \ in. 

 thick, and to these the wire was attached "end on," but speech 

 could be distinctly heard by laying such a disc on any inter- 

 mediate point of the wire. When the wire was particularly still 

 speech was audible up to 200 yards.— Mr. G. W. von Tunzel- 

 mann then read a paper on the production of thermo-electric 

 currents in wires subjected to mechanical strain. The wire, of 

 iron, steel, or copper, was stretched vertically between two cans 

 which could be maintained at different temperatures. It was 

 fixed in the base of the lower can and held in the npper one by 

 a clamp attached to the shorter arm of a lever, to the longer arm 

 of which the stretching weight was applied. The free ends of 

 the wire were joined to copper wires which led to the Thomson 

 galvanometer, these junctions being covered with cotton wool. 

 He has succeeded in reconciling the contradictory conclu- 

 sions arrived at by Sir W. Thomson and M. Le Roux ; 

 whereas the former only used moderate strains, the latter worked 

 near the breaking limit, and the author finds that if the weight 

 be gradually increased the direction of the current changes, and 

 hence these two authorities found the currents to flow in oppo- 

 site directions. A great number of experiments were made, 

 and from them it is evident that on applying a strain the deflec- 

 tion does not immediately attain a maximum, but it gradually 

 rises for about eight minutes, and then gradually falls, attaining 

 a stationary point at the end of about twelve minutes. —Prof. 

 Adams then exhibited a simple arrangement for projectmg 

 Lissajous' figures on to the screen which has been made by his 

 assistant, Mr. Furze. It consists of two strong straight steel 

 springs, fixed in separate heavy iron frames, the one horizontally 

 and the other vertically. The latter carries at its end a double 

 convex lens arvi the former carries a black disc perforated with a 



small hole and is so mounted that its length may be varied as 

 recjuired. If now the disc be placed before the lamp and the 

 pomt of light be focussed on the screen by means of the lens on 

 the vertical spring, the two springs may be caused to vibrate 

 and the spot will describe a figure corresponding to their relative 

 rates. — Dr. Guthrie exhibited an experiment to show the be- 

 haviour of colloids and crystalloids in relation to electrolysis. A 

 solution of gelatine was coloured with litmus, made acid and 

 mixed with sulphate of soda ; two platinum poles of a 6-cell 

 Groves' battery were then immersed in it and the gelatine was 

 allowed to set. The mass became comparatively clear round 

 the positive pole and red and blue clouds were formed which 

 met across a space of about i^ in. in three-quarters of an hour. 

 The relative advance of the ions was indicated by the brightening 

 of the litmus round one pole and by the blue coloration pro- 

 duced at the other. 



Chemical Society, April 4. — Dr. Gladstone, president, in 

 the chair. — A lecture " On the Application of the Microscope to 

 some Special Branches of Chemistry " was delivered by Mr, H. 

 C. Sorby, F.R.S. The lecturer confined his discourse to the 

 application of the microscope for determining the refractive 

 indices of liquids and solids. An object is placed on the stage 

 of a microscope and the focus adjusted accurately ; on covering 

 the object with a plate of some refracting substance, the object 

 will be invisible ; to bring it again into focus the body of the 

 microscope must be moved further out. If this distance be 

 "rf" and the thickness of the plate be T, then the index of 



refraction = — — — . This distance can be measured either by 



T — d 

 a scale and vernier attached to the body of the microscope or 

 by graduating the head of the screw which works the fine adjust- 

 ment. The lecturer then described the various methods by 

 which the two quantities 7" and ^ could be practically measured 

 to TTrin)th of an inch ; the curious and diversified images seen by 

 observing with a microscope a circle or a grating through 

 transparent plates of various substances were then explained. 

 Minerals having no double refraction are unifocal, i.e., both 

 systems of lines in a grating can be seen at the same focus. 

 Minerals having double refraction are bifocal, i.e., only one 

 system of lines can be seen at one focus, a new focus having to be 

 found in order to see the lines at right angles to the first set. 

 This method has enabled the author to identify various minerals 

 in sections -^th inch thick and rk^ih. inch in diameter. Thus 

 in a dolerite ^th inch thick, a zeolite, labradorite, calcite, and 

 augite were identified with almost absolute certainty. In sec- 

 tions of shells TWTrth of an inch thick calcite can be easily dis- 

 tinguished from arragonite. In conclusion the lecturer referred 

 to the connection between the indices of refraction and chemical 

 composition ; the data are defective at present, but several points 

 have already been made out ; thus of two minerals having similar 

 compositions, but one containing calcium and the other one of 

 the alkalies, the first has a higher index of refraction ; a lime 

 garnet on the other hand has a lower index than a precious 

 garnet which contains iron instead of calcium. 



Linnean Society, April 4.— W. Carruthers, F.R.S. , vice- 

 president, in the chair.— There was exhibited by Dr. H. Trimen 

 the base of the stem of the Water Hemlock {Cieuta virosa, 

 Linn.) in its floating winter state, obtained near Yarmouth. This 

 was well figured in the Phil. Trans, last century, but since has 

 seldom been referred to by botanists.— Mr. G. Murray showed 

 under the microscope specimens of growing Saprolegnia, exhi- 

 biting terminal and interstitial oogonia.— A paper on some 

 minuTe hymenopterous insects, by Prof. J. O. Westwood was, in 

 his absence read by Mr. McLachlan. This contains descriptions 

 of the following new forms : Mymar iaprobanicus, M. wolas- 

 ionii, Alaptus excisus, Oligosita subfasciata, O. stanforthii, O. 

 nodicornis, and Trichogramvia erosicornis. All singular insects 

 alike interesting structurally and as regards habits, &c.— A short 

 notice was made by Mr. M. C. Cooke on a collection of fungi 

 from Texas, made by Mr. Ravenel. Adding all other recorded 

 species the series shows that much yet remains unknown in the 

 mycologic flora of what probably is one of the richest States of 

 the Union. — The Secretary read some remarks on the pectdiar 

 properties ascribed to a fungus by the Samoans, by the Rev. 

 Thos. Powell. The natives name it " Limamea " ; specimens of 

 which have been forwarded to the Rev. M. Berkeley for identi- 

 fication. It destroys their bread-fruit trees and the Chestnut 

 (Inocarpus edulis). An antidote to its ravages is said to exist in 

 the liliaceous plant Critium a9iaticum,\Ms^ the natives grow 



