Dec. 1 6, I 



NATURE 



163 



Royal Society of Literature, November 24 — Mr. Charles 

 Clark, vice-president, in the chair. — Sir Hardinge Stanley 

 Giffard, Mr. Ramchundra Ghose, Mr. Henry Allpass, Mr. 

 I Robert White Boyle, Capt. W. Deane Seymour, Dr. Altschul, 

 ' were elected members. — Mr. F. G. Fleay read a paper entitled 

 ' the living key to English spelling reform now found in history 

 and etymology. The object of Mr. Fleay's paper was to show 

 that the objections to spelling reform are principally founded on 

 an exaggerated estimate of the amount of change required. This 

 exaggeration has been caused by the revolutionary proposals of 

 the leading reformers, who neglected the history of our language 

 and the etymological basis of its orthography in favour of philo- 

 sophical completeness. Mr. Fleay, on the other hand, proposed 

 a scheme which was developed in two forms one perfectly 

 • phonetic for educational prnposes, the other diftering from this 

 only in dropping the use of the accents and the one new tyjie 

 required in the former. He showed that even in the vowel 

 sounds not one-tenth would need alteration, while in the case of 

 the consonants the alteration required would of course be much 

 less. 

 I Photographic Society, November 9. — J. Glaisher, F.R.S., 

 president, in the chair. — Major Waterhouse, Bengal Staff Corps, 

 read a paper "On a new method of obtaining 'grain ' in photo- 

 engi-aving." The method alluded to was to squeeze into the 

 gelatine relief, while wet, sand- or glass-paper, previously waxed 

 to ensure removal. The contraction of the paper while drying 

 would force the granular substance into the relief more strongly 

 in the shadows than in the lights, and thus a discriminating grain 

 would be produced. — Capt. Abney, R.E., F.R.S., read a paper, 

 "Notes on the gelatine process." The point insisted upon was 

 that gelatine emulsions if kept some time before being poured 

 upon the plates, extra sensitiveness would be the result ; another 

 matter was, that "frilling " could be prevented by the same long 

 keeping of the emulsion ; also that w'lXh emulsions where silver 

 iodide is used, a few drops of hyposulphite of soda would bring 

 out more detail in the image. 



Cambridge 

 Philosophical Society, November S. — Prof. Newton, pre- 

 ' sident, in the chair. — The following communications were made 

 : to the Society : — On a new arrangement for sensitive flames, by 

 ■ Lord Rayleigh. A jet of coal-gas from a pin-hole burner rises 

 J vertically in the interior of a cavity from which the air is ex- 

 1 eluded. It then passes into a brass tube a few inches long, and 

 on reaching the top burns in the open. The front wall of the 

 cavity is formed of a flexible membrane of tissue paper, through 

 which external sounds can reach the burner. Tire principle is 

 the same as that of Barry's flame described by Tyndall. In 

 both cases the utiignilcJ part of the jet is the sensitive agent, 

 and the flame is only an indicator. Barry's flame may be made 

 very sensitive to sound, but it is open to the objection of liability 

 to disturbance by the slightest draught. A few years since Mr. 

 Ridout proposed to inclose the jet in a tube air-tight at the 

 bottom, and to ignite it only on arrival at the top of this tube. 

 In this case however external vibrations have very imperfect 

 access to the sensitive part of the jet, and when they reach it 

 they are of the wrong quality, having but little motion transverse 

 to the direction of the jet. The arrangement now exhibited 

 combines very satisfactorily sensitiveness to sound and insen- 

 sitiveness to wind, and it requires no higher pressure than 

 that of ordinary gas-pipes. If the extreme of sensitive- 

 ness be aimed at, the gas pressure must be adjusted until 

 the jet is on the point of flaring without sound. The 

 apparatus exhibited was made in Prof. Stuart's workshop. An 

 adjustment for directing the jet exactly up the middle of the 

 brass tube is found necessary, and some advantage is gained by 

 contracting the tube somewhat at the place of ignition. — Lord 

 Rayleigh, on an effect of vibrations upon a suspended disk. In 

 the British Association experiment for determining the unit of 

 electrical resistance, a magnet and mirror are inclosed in a 

 wooden box, attached to tlie lower end of a tube through which 

 the silk suspension fibre passes. Under these circumstances it 

 Is found that the slightest tap with the finger-nail upon the box 

 deflects the mirror to an extraordinary degree. The disturbance 

 appears to be due to aerial vibrations within the box, acting upon 

 the mirror. We know that a flat body, like a mirror, tends to 

 set itself across the direction of any steady current of the fluid in 

 which it is immersed, and we may fairly suppose that an effect 

 of the same character will follow from an alternating current. 

 At the moment of the tap upon the box the air inside is made to 

 move past the mirror, and probably executes several vibration.s. 



While these vibrations last the min-or is subject to a twisting 

 force tending to set it at right angles to the direction of the 

 vibration. The whole action being over in a time very small 

 compared \\ith that of the free vibrations of the magnet and 

 mirror, the observed effect is as if an impulse had been given to 

 the suspended parts. The experiment shown is intended to illus- 

 trate this effect. A small disk of paper, about the size of a 

 sixpence, is hung by a fine silk fibre across the mouth of a 

 resonator of pitch 128. When a sound of this pitch is excited, 

 there is a powerful rush of air in and out of the resonator, and 

 the disk sets itself promptly across the passage. A fork of 

 pitch 128 may beheld near the resonator, but it is better to use 

 a second resonator at a little distance, in order to avoid any 

 possible disturbance due to the neighbourhood of the vibrating 

 prongs. 



Paris 

 Academy of Sciences, November 29. — M. Edm. Becquercl 

 in the chair. — MM. E. and J. Brongniart presented a work on 

 the silicified fossil seeds of strata of Autun and Saint Etienne, 

 to which their father had devoted the closing years of his life. 

 These researches led, among other things, to observation of a 

 pollinic chamber in some living as well as in fossil species of 

 seeds. — Note relating to a memoir on vision of material colours 

 in rotation, and velocities estimated in figures by means of the 

 turning-plate apparatus of General Morin, for observation of 

 the laws of motion, by M. Chevreul. — On the spontaneous oxida- 

 tion of mercury and of metals, by M. Berthelot. He concludes 

 from experiment that mercury, like iron, zinc, cadmium, lead, 

 copper, and tin, undergoes, in contact with air, a superficial 

 oxidation, very slight, indeed, and limited by the difficulty of 

 renewal of the surfaces and the absence of contact resulting from 

 commenced oxidation. This agrees with thermic data. The 

 oxidation of mercury liberates per equivalent of fixed oxygen 

 •f 2l"i cal. (iron jrg, tin 34*9, &c.). -Spontaneous oxidation 

 is not [appreciable in metals whose heat of oxidation is very 

 small, e.g. silver (-f 3'5 cal.). The greater rapidity of the reac- 

 tion where an agent intervenes, which is capable of combining 

 (with liberation of heat) with the substance produced, e.g. an 

 acid, is shown to be in agreement with thermic theory. — On the 

 propagation of light, by AL Gouy. He examines the case in 

 which the rays have a constant direction, but vary in intensity, 

 the source undergoing variations or being eclipsed by a moving 

 screen. There is not, for a given homogeneous source, a deter- 

 minate velocity of hght, independent of the manner in which the 

 amplitude is varied. But in every realisaljle experiment this 

 variation is effected in a gradual and very slow manner relatively 

 to the vibratoi7 period ; here the formulce are simplified and the 

 amplitude is transported as in a non-dispersive medium (with a 

 velocity which is indicated by formula). The index of refraction 

 is 'connected %\ith the velocity of light by a relation easy to 

 establish. — On linear dift'erential equations with periodic coefti - 

 cients, by M. Floquet. — On a new electric property of selenium, 

 and on the existence of tribolectric currents properly so-called, 

 by M. Blondlot. To one pole of a capillary electrometer a piece 

 of annealed selenium is attached with a platinum wire ; to the 

 other pole a platinum'plate. If the selenium be brought (with an 

 insulating handle) into contact with the platinum the electro- 

 meter remains at zero ; but on rubbing the selenium against the 

 platinum a strong deflection occurs (often equal to that pro- 

 duced by a sulphate of copper element). The thermo-electric 

 current got by heating the selenium-platinum contact has 

 an opposite direction to that of the current in question (wh-ch 

 is from the unrnbbed to the i-ubbed part of the selenium) ; thus 

 the effect cannot be attributed to heat. On ceasing to rub, 

 the deflection persists ; the selenium, which let pass the high- 

 tension electricity due to friction, opposing too great re-istance 

 for the weak polarisation of the mercury. Shock and even 

 pressure produce the same effect as friction, though in less degree. 

 — Action of phosphorus on hydriodic and hydrobromic acids, 

 by M. Damoiseau. — On Waldivine, by M. Tanret. This is the 

 active principle of the fruit of Simaba -ualdivia, which grows in 

 Columbia. The composition of the ciystals is represented by 

 CjiiHo^OjoSHO. The physical and chemical properties are 

 described*. — Direct analysis of peat ; its chemical constitution, by 

 M. Guignet. This relates to peat of very modern formation in 

 the Somme Valley, formed under water in presence of carbonate 

 of lime. Treated with water it yields ci-cnic and apocrenic acid, 

 also a little sulphate of lime. Alcohol at 90° produces a clear 

 green solution, from which vegetable wax is got in abundance 

 (the green matter has all the characters of chlorophyll). The 



