1 66 



NATURE 



{Dec. 15, 1887 



as seven reglows have been observed during one cooling. 

 Generally two decided ones are observed, one between 500° and 

 1000° C, and the other below 500° C. The eftects the author 

 believes due to " retentiveness " of the material, somewhat 

 similar to the causes of residual magnetism and residual charge 

 of a Leyden jar. A table of experimental results, giving the 

 torsional elasticity and internal friction at different temperatures, 

 for iron wire, showed sudden increases in internal friction at tem- 

 peratures of about 550° and 1000° C. The table also shows that the 

 torsional elasticity ■■lowly decreases as the temperature increases, 

 whereas the internal friction increases enormously. This explains 

 why bells cease to emit musical notes when heated. Tlie author finds 

 that the recalescence at the hiijher temperature is not appreciably 

 accelerated by mechanical vibration such as hammering, &c. , 

 but those occurring at lower temperatures are greatly influenced 

 by such treatment and by magnetic disturbances. Prof. Forbes 

 believed the explanation of recalescence given by himself about 

 1873 is sufficient to account for the effects observed. This ex- 

 planation postulates a sadden increase in thermal conductivity 

 about the temperature at which recalescence occurs, which 

 permits the heat from the inside to reach the outride more readily, 

 and thus raise the temperature of the surface. The subsequent 

 reglows observed by Mr. Tomlinson he believes due to con- 

 vection currents of air. Prof. Riicker suggested that calorimetric 

 experiments might determine which view was the true one, and 

 Prof. Ayrton thought the question might be decided by having 

 two half-round bars nearly in contact at their flat sides, heated 

 up and allowed to cool, and noting whether any sudden change 

 in the bending of each bar (due to unequal temperature at the 

 inner side and outer sides) took place about the critical 

 temperature.- — On the rotation of a copper sphere and of 

 copper wire heliies when freely suspended in a magnetic 

 field, by Dr. R. C. Shettle. The author exhibited the apparatus 

 with which his experiments "on the supposed new force" 

 were made, the results of which were published in the Electrician, 

 vol. xix. Dr. Hofford has recently made similar experiment-;, 

 usirjf' brass disks, and his results seem to point to " diamagnetic 

 non-uniformity " of the disks as the cause of the phenomena he 

 observed. 



Linnean Society, December i. — ^W. Carruthers, F.R.S., 

 President, in the chair. — There was exhibited for Mr. O. Fraser, 

 of Calcutta, a specimen supposed to be a weather-worn seed of a 

 palm, picked up on the Madras coast. Opinions given at the 

 meeting referred it to the consolidated roe of a fish, doubts being 

 thrown on its vegetable nature. — Sir John Lubbock read a paper, 

 an account of which we have already printed, on the habits of 

 ants, bees, and wasps. — A paper was read by Mr. C. B. Clarke, 

 on a new species of Panictim with remarks on the terminology 

 of the Gramine^. 



Geological Society, November 23.— Prof. J. W. Judd, 

 F.R.S., President, in the chair. — The following communications 

 were read : — Note on a New Wealden Iguanodont, and other 

 Dinosaurs, by R. Lydekker. — On the Cae Gwyn Cave, by Prof. 

 T. McKenny Hughes, who contended that the drift outside the 

 cave was a marine deposit remanie from older beds of glacial 

 age, but was itself post-glacial and of approximately the same 

 date as the St. Asaph drift. He maintained that the marine 

 drift was deposited before the occupation of the cave by the 

 animals whose remains have been found in it ; that at the time 

 of the occupation of the cave the upper opening now seen did 

 not exist, but the animals got in by the other entrance ; that 

 against the wall of the cave where it approached most nearly to 

 the face of the cliff, the drift lay thick as we now see it ; that by 

 swallow-hole action the cave was first partially filled, and then 

 the thinnest portion of its wall gave way gradually, burying the 

 bone-earth below it, and letting down some of the drift above it, 

 so that some of it now looks as if it might have been laid down 

 by the sea upon pre- existing cave-deposits. The reading of this 

 paper was followed by a discussion, in the course of which Dr. 

 Hicks argued strongly against the author's conclusions. 



Mathematical Society, December 8. — Sir J. Cockle, 

 F.R.S., President, in the chair. — Messrs. W. B. Allcock, J. 

 W. Mulcaster, and I. Beyens, Cadiz, were elected members. — 

 The following communications were made : — The algebra of 

 linear partial differential operators, by Capt. Macmahon, R.A. 

 — On a method in the analysis of ternary forms, by J. J. 

 Walker, F. R.S. — Confocal paraboloids, by A. G. Greenhill. — 

 Note on the solution of Green's problem in the case of the 



sphere, by A. R. Johnson. — Uni-Brocardal triangles and their 

 inscribed triangles, by R. Tucker. 



Chemical Society, November 17. — Mr. William Crookes, 

 F. R.S., President, in the chair. — The following papers were 

 read : — Zinc-copper and tin-copper alloys, by A. P. Laurie. — ■ 

 The halogen substituted derivatives of benzalmalonic acid, by 

 C. M. Stuart. — Note on a modification of Traube's capillari- 

 meter, by IL S. Elw( rthy. — The formation of hyponitrites : a 

 reply, by Edward Divers, F.R.S. — Reply to the foregoing note, 

 by W. R. Dunstan. 



Royal Microscopical Society, November 9. — Rev. Dr. 

 Da'linger, F. R.S., President, in the chrdr. — Mr. E. M. Nelson 

 called attention to a suggestion for supplying a want which 

 many had felt of a really good achromatic single lens or loupe 

 for microscopic purposes, of ^-inch foca«. He had found that 

 the want was met by a Seibert No. LIL objective, having its 

 adjusting screw removed. — Mr. Nelson further said that, having 

 lately obtained an improvement in optical power, he had been 

 able to do a little more in the matter of resolution, and one of 

 the first objects he had tried was striperl muscular fibre. In the 

 eai-ly days of microscopy a muscular fibril used to be represented 

 as a series of light and dark bands, the dark band being about 

 twice the diameter of the white band. In 1854 Mes^rs. Huxley 

 and Busk discovered a dark stripe in the middle of the bright 

 band, and subsequently Hensen placed a similar darker stripe 

 in the middle of the dark band. With his latest optical appli- 

 ances he had been able to see a faint white stripe on either side 

 of Hensen's dark stripe. He estimated the diameter of the 

 stripes to be all equal. Although he saw evidences of long' 

 tudinal breaking up, he could see nothing of Schafer's "beads. 

 — The third point noticed by Mr. Nelson was Mr. Francis' 

 method of improving definition of such an object as Amphipleura 

 pelliicida by uring the analyzer. He had tested the plan, and 

 found that it did intensify the resolution in a very marked 

 degree. — Mr. Nelson also exhibited and described a new port- 

 able microscope made by Messrs Powell and Lealand from his 

 drawings, and the new photomicrographic camera designed by 

 Mr. C. L. Curties and himself. — Mr. Nelson further exhibited a 

 new eye-piece which he had devised. Having for some time 

 pa'.t made a great many experiments with achromatic eye-pieci 

 of double, triple, and other forms, he had not succeeded in pr > 

 ducing any combination whose defining power surpassed that oi 

 the Huyghenian. The best results were obtained by achromat- 

 izing the eye-lens — i.e. by making it of a bxonvex and a plano- 

 concave, with its convex side towards the eye. The aperture of 

 the diaphragm was reduced until the diameter of the field was 

 equal to that of the Abbe compensating eye piece. This eye- 

 piece, with the achromatized eye-lens, gives the sharpest images 

 he had seen. It works perfectly well with the 24 mm. and 

 3 mm. Zeiss apochromatic objectives. — Mr. C. R. Beaumont 

 then exhibited and described his new form of slide for observing 

 living organisms, and read a paper on the metamorphoses of 

 AiiiabcB and Actinophrys, in which he claimed to have observed 

 the development of an Aviaba into an Aclinophiys, and then 

 into a Di[ilugia and an Arcel'a. — Mr. H. B. Brady's paper, a 

 synopsis of the British recent Foraminifera, was communicated 

 to the meeting by Prof. Bell. 



Paris. 



Academy of Sciences, December 5,— M. Janssen in the 

 chair.- — Letter to M. Bertrand in connection with his previous 

 note on a theorem relative to errors of observation, by M. Faye. 

 It is pointed out that, if we consider all the combinations of 

 errors, the relations of the sums corresponding to the greatest 

 and smallest of these errors are comprised between the extremes 

 I and 3'9i5. Both of these are infinitely improbable in them- 

 selves, while their mean, 2'457, differs little from the number 

 2'4i4 given by M. Bertrand. — Reply to M. Mascart on the sub- 

 ject of the deviation of the winds on the synoptical charts, by 

 M. Faye. The author insists that he has nothing to modify in 

 what he has written during the last thirteen years on the de- 

 scending spiral motion of cyclones. The synoptical charts, 

 which have been multiplied during the last few years, when 

 properly interpreted, are shown to be in no way opposed, but, 

 on the contrary, lend additional support, to his theory. — On the 

 synchronism of accurate time-pieces, and on the distribution of 

 time, by M. A. Cornu. A description is given of the construc- 

 tion and properties of a very simple electric appliance,' which is 

 applicable to all kinds of oscillating apparatus, and which 



