46 



NA TURE 



[May io, 1900 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, February i. — "Researches on Modern 

 Explosives : Second Communication." ByW. Macnab, F.I.C., 

 and E. Ristori, Assoc. M.Inst.C.E., F.R.A.S. Communicated 

 by Prof. Ramsay, F.R.S. 



The object of the experiments was to endeavour to find a 

 means of determining more accurately than has hitherto been 

 done the temperature reached when an explosive is fired in a 

 closed vessel. 



A modification of the method developed by Sir W. C. 

 Roberts-Austen was employed. A thin platinum wire was 

 melted by the heat of the explosion, but a thick wire was un- 

 altered. This showed that the temperature reached was above 

 the melting point of platinum, and also that the duration of the 

 maximum temperature was very short. From this it was 

 argued that if rhodium-platinum couples of different diameters, 

 sufficiently thick not to be melted during explosion, were used 

 in a bomb, the deflections of the galvanometer indicated would* 

 vary inversely with the sizes of the wires forming the couples ; 

 that in this way data might be obtained from which might be 

 calculated the deflection of an infinitely thin couple, which 

 could be capable of taking up the heat in an infinitely short 

 time, and that this deflection expressed in degrees would repre- 

 sent the actual temperature reached. 



Couples formed of wires of pure platinum and platinum 

 alloyed with lo per cent, of rhodium, varying in diameter from 

 0"0i to 0'044 of an inch, were employed. Each couple was 

 successively fixed inside the bomb, and on firing the explosive 

 the deflection of a spot of light reflected from the mirror 

 galvanometer was photographically recorded. 



These records show the uniformity of the results, and also the 

 time occupied in heating each couple to its maximum, and that 

 the deflections are in inverse order to the thickness of the 

 couple used. 



Two series of experiments made with two diff"erent explosives 

 — ballistite (composed of 30 per cent, nitroglycerine and 70 per 

 cent, gun-cotton) and gelatinised gun-cotton — were carried out 

 with a number of diff"erent couples,' and the results expressed as 

 curves show the gradual rise of the deflections as the thickness 

 of the couple diminishes ; but all through the gun-cotton curve 

 is below the ballistite curve, thus indicating that the temperature 

 reached during explosion of the gun-cotton is lower than that of 

 the ballistite. 



Experiments made with the following explosives showed that 

 the relative temperature can be easily ascertained. Gun-cotton 

 gave the lowest temperature, and in order came cordite, ballis- 

 tite (composed of 70 per cent, soluble nitro-cotton and 30 per 

 cent, nitroglycerine) and ballistite (composed of 50 per cent, 

 soluble nitro-cotton and 50 per cent, nitroglycerine). 



Another series of experiments is in progress for determining 

 the other necessary elements which will be required before the 

 value of these deflections of the galvanometer can be accurately 

 expressed in degrees of temperature. 



April 5. — " Uber Reihen auf der Convergenzgrenze." Von 

 Emanuel Lasker, Dr. philos. Communicated by Major 

 MacMahon, F.R.S. 



Linnean Society, April 19.— Dr.A.Gunther, F R.S., Presi- 

 dent, in the chair.— On behalf of the Hon. Charles Ellis, the 

 President exhibited photographs of a large tree, laxodium 

 distichuin, growing at Oaxaca in Mexico, and of another 

 gigantic tree, a native of Cambodia. The circumference of the 

 former, at a height of 3 feet from the ground, was stated to be 

 143 feet, while the height was estimated to be not more than 

 100 feet. The native name for this tree is Sabino. Mr. Daydon 

 Jackson read an account of it, quoting from Loudon's Mag. Nat. 

 Hist. vol. iv. (1831), p. 30, and Humboldt's "Views of 

 Nature," p. 274. The second gigantic tree, which could not be 

 satisfactorily determined from the photograph, had been ob- 

 served growing on the Makong River, near the celebrated ruins 

 of the great city of Angkorwat in Cambodia.— Messrs. W. B. 

 Hemsley and H H. W. Pearson read a paper on some collec- 

 tions of high-level plants from Tibet and the Andes. Mr. 

 Hemsley first gave a brief history of the botanical exploration of 

 Tibet, followed by an account of the unpublished collections 

 presented to Kew by Captain Wellby and Lieut. Malcolm, 

 by Captain Deasy and Mr. Arnold Pike, and by Dr. Sven 

 Hedin. These collections were all made at great altitudes in 

 Central and Northern Tibet; few of them below 15,000 feet, 



NO. 1593, VOL. 62] 



and some of them at 19,000 feet and upwards. The highest 

 point at which flowering plants had been found was 19,200 feet 

 above the level of the sea. The plants recorded by Deasy and 

 Pike at altitudes of 19,000 feet and upwards are : — Corydalis 

 Hendersoni, Arenaria Stracheyi, Saxifraga parva, Sedum 

 Stracheyi, Saussurea hracteata, Gentiana tenella, G. aqiiatica, 

 an unnamed species of Astragalus, and an unnamed species of 

 Oxytropis. These are the greatest altitudes on record for 

 flowering plants. Deep-rooting perennial herbs having a 

 rosette of leaves close to the ground, with the flowers closely 

 nestled in the centre, are characteristic of these altitudes. The 

 predominating natural orders are : — Compositae, Leguminosae, 

 Cruciferse, Ranunculaceae and Graminese. The Compositoe 

 largely predominate, and the genus Saussurea is represented by 

 numerous species. Specimens of about a dozen species were 

 shown to illustrate the great diversity exhibited by this genus in 

 foliage and inflorescence. Liliacese and the allied orders were 

 very sparingly represented. Two or three species of onion 

 occur ; one of them, Allium Semenovii, in great abundance up 

 to 17,000 feet. None of the collections contained any species 

 of orchid. — Mr. H. H. W. Pearson described the Andine 

 flora, with special reference to Sir Martin Conway's small col- 

 lection of plants brought from Illimani in the Bolivian Andes 

 in 1898. In consequence of the labours of d'Orbigny, Pentland, 

 Meyen, Weddell, Mandon and other botanists, the high-level 

 flora of the mountains of Bolivia is better known than that of 

 any other equally elevated region of the Andes. Weddell's 

 collections form the nucleus of the materials from which the 

 "Chloris Andina" — the classic work on the flora of the High 

 Andes — was prepared. Many collectors have obtained plants 

 in various parts of the Andes at elevations stated to be greater 

 than 17,000 feet. Colonel Hall states that he saw four plants on 

 Chimborazo in 1831 at " nearly 18.000 feet." These were two 

 species of Draba, one of which was D. aretoides, H. B. K. , 

 and two Composites, one being a Culcitium. Mr. Whymper 

 and others have thrown st^me doubt upon the determination of 

 this elevation, and it is probable that it was over-estimated. Out 

 of forty-six species of flowering plants obtained by Sir Martin 

 Conway, seven are from 18,000 feet or above it, two being as 

 high as 18,700 feet. These, the highest Andine plants on 

 record, are Malvastrum flabellatuin, Wedd. , and Deyeuxia 

 glacialis, Wedd. Thirty-nine species in this collection were 

 found above 14,000 feet ; these belong to thirty-four genera and 

 twenty-one natural orders ; fifteen {i.e. about three-eighths of the 

 collection) are Compositae. Of the thirty-tour genera, one only 

 — Blumenbachia — is endemic to South America. The species, 

 with one exception, are confined to the Andes, eight or nine of 

 them not being found outside Bolivia. In the collection made 

 by Mr. Fitzgerald's expedition in the Aconcagua valleys be- 

 tween 8000 and 14,000 feet, ten genera [i.e. one quarter of the 

 whole) are endemic in South America. The contrast between 

 this and the small endemic element in the Conway collection 

 from above 14,000 feet gives additional support to the generalisa- 

 tion that the flora of high levels is more cosmopolitan than that 

 of low levels. — A paper was read by Mr. E. S. Salmon on some 

 mosses from China and Japan. 



Manchester. 

 Literary and Philosophical Society, April 24. — Prof. 

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

 gentlemen were elected honorary members of the Society :— 

 Prof. James Dewar, F.R.S., London; Prof. J. A. Ewing, 

 F.R.S., Cambridge; Prof. A. R. Forsyth, F.R.S., 

 Cambridge; Prof. James Geikie, F.R.S., Edinburgh; 

 Prof. Ernst H. P. A. Haeckel, Jena ; Prof. H. A. Lorentz, 

 Leyden ; Mr. Robert Ridgeway, Washington, U.S.A. ; and 

 Mr. Beauchamp Tower, London. The following were elected 

 officers of the Society for the session 1 900-1 :— President, Prof. 

 Horace Lamb, F.R.S. ; vice-presidents. Prof. O. Reynolds, 

 F.R.S. ; Mr. Charles Bailey ; Prof W. Boyd Dawkins, F.R.S., 

 and Mr. J. Cosmo Melvill ; hon. secretaries, Mr. Francis Jones 

 and Prof. A. W. Flux ; treasurer, Mr. J. J. Ashworth ; hon. 

 librarian, Mr. W. E. Hoyle. 



Paris. 

 Academy of Sciences, April 3c. — M. Maurice Levy in 

 the chair.— On the telescopic planets, by M. C. de Freycinet. 

 The ideas of Laplace upon the distribution of the telescopic 

 planets in concentric spherical layers round the sun are developed 

 analytically and confirmed. If the asteroids are divided into 



