November 28, 1901] 



NA TURE 



Teachers and students of botany often find it difficult to obtain 

 the plants or other botanical material required by them for exam- 

 ination. A pamphlet received from Messrs. James Backhouse 

 and Son, Ltd., The Nurseries, York, reminds us that this 

 firm has a special scientific department for the purpose of sup- 

 plying living and preserved material for use in classes or private 

 study. Practically every specimen or preparation required in a 

 course of botany is kept on hand ready for dispatch, and if it is 

 not in stock it will be obtained. The facilities thus afforded 

 for obtaining botanical material should promote the study of 

 botany in schools and encourage investigation by private 

 students. 



SiN'CE the classical work of Bunsen on the cacodyl compounds, 

 many attempts have been made to prepare monomethylarsine, 

 the analogue of methylamine, hitherto without success. In the 

 Beriilili for November 9, Messrs. A. W. Palmer and W. H. 

 Dehn give an account of the preparation of this substance in a 

 pure state. Indications of the existence of such a compound 

 were obtained three years ago, by the reduction of methyldi- 

 chlorarsine, but as this is costly and difficult to prepare, a more 

 suitable starting point was found in cacodylic acid. This on 

 reduction with amalgamated zinc dust and hydrochloric acid gives 

 the CHj. AsHj, which is separated from the hydrogen which 

 accompanies it by passing through a U-tube surrounded by a 

 mixture of solid carbon dioxide and ether. Monomethylarsine 

 is a colourless, mobile liquid, which boils under ordinary 

 atmospheric pressure at 2' C. and possesses the penetrating ob- 

 jectionable smell of cacodyl. It rapidly attacks indiarubber, 

 and combines immediately with oxygen, without, however, 

 catching fire spontaneously, in this respect differing from 

 dimethylarsine. The production of monophenylarsine from 

 monophenylarsenic acid is described in the same paper. 



In continuing his researches on ammonium amalgam M. 

 Moissan has arrived at some interesting results which he de- 

 scribes in the current number of the Coiiiples rendus. Sodium 

 amalgam was allowed to act upon ammonium iodide in so- 

 lution in liquid anhydrous ammonia at a temperature of about 

 — 39'C. Under these conditions the sodium amalgam reacts 

 upon the ammonium iodide and becomes more fluid, without 

 the formation of any gas. The sodium iodide formed together 

 with the excess of sodium were then removed by liquid ammonia 

 at a temperature of - 40° and then with ether at - 80° C. The 

 solid ingot thus produced was then placed in a tube kept at 

 -90" and connected with a mercury pump. It was found that 

 a perfect vacuum could be maintained in the apparatus without 

 any gas being given off by the ingot. The temperature was 

 then allowed to rise, when a mixture of ammonia and hydrogen 

 gases in the proportion of two of the former to one of the 

 latter was given off. All these facts would appear to point 

 to the conclusion that the radical NH4 is actually present in the 

 metallic mass prepared at -39', but M. Moissan believes that 

 this is not really the case, there being a possibility that a 

 metallic ammoniacal hydride is formed. He has found that 

 when sodium amalgam reacts with a solution of ammonia in 

 water, there is a slow evolution of gas without foaming. If, 

 however, sodium hydride in solution in sodium amalgam is 

 placed in the same liquid, there is at once a foaming mass 

 produced, which may last for two or three days. Further ex- 

 periments are promised in this direction. 



The additions to the Zoological Society's Gardens during the 

 past week include a Chacma Baboon (Cynocephahis ponariiis) 

 from South Africa, presented by the Lord Dunleath ; a Toque 

 Monkey ( Macacus pileatiis) from Ceylon, presented by Mrs. de 

 Koop ; a White-crowned Mangabey (Cercocebus aelliiops) from 

 NO. 1674, VOL. 65] 



West Africa, presented by Mr. S. J. Dean ; a Grecian Ibex 

 (Capra aegagrus), South-East European, presented by Mr. B. A. 

 Isaac; a Common Water Buck (Cobus ellipsipryiiinus) from 

 South Africa, four Viscachas {Lagoslomiis trichodactylus) from 

 Buenos Ayres, a Black-headed Oriole {Oriolus melanocephalus), 

 an Orange-headed Ground Thrush (Geocichla citritia), two 

 Indian Shamas {Cittocincla macntra) from India, deposited. 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences in December. 

 Dec. 3. I3h. Juno in conjunction with moon. Juno 

 0° 14' S. 

 4. 22h. Venus at greatest elongation, 47° 15' E. 

 9. 9h. Uranus in conjunction with the sun. 

 11-13. Epoch of the Geminid meteoric shower (radiant 



109' + 33')- 



13. 23h. Mars in conjunction with Saturn. Mars 



1° 18' S. 



14. 6h. 43m. to 7h. 39m. Moon occults /3 Capricorni 



(mag. 3-4). 



15. Venus. Illuminated portion of disc = '445. 

 Mars. Illuminated portion of disc = '980. 



16. 9h. 46m. Minimum of Algol (/8 Persei). 



17. 3h. Mars in conjunction with Jupiter. Mars 



0° 52' S. 



iS. 7h. 24m. to 8h. 9m. Moon occults K Piscium 

 (mag. 47). 



19. 6h. 35m. Minitnum of Algol (B Peisei). 



22. ih. Sun enters Capricornus. Winter commences. 



22. 2h. Neptune in opposition to the sun. 



23- 5h. 53m. to 6h. 12m. Moon occults e Tauri 

 (mag. 37). 



27. loh. 42m. to llh. 50m. Moon occults A- Cancri 

 (mag. 5-8). 



31. gh. Juno in conjunction with the moon. Juno 

 0° 18' N. 

 Leonid Meteors, November 1901. — Mr. G. C. Thompson 

 sends the results of observations at Penarlh of Leonid and sporadic 

 meteors on the nights of November 14-15 and 15-16. Between 

 November 14, 11.35 p.m., and November 15, 1.55 a.m., four 

 bright Leonids were observed, all exhibiting characteristic green 

 streaks, four probable Leonids, without streaks or train, one of 

 doubtful origin, and four sporadic meteors. On the night of 

 November 15-16 no meteors were observed until after midnight, 

 but between 12.20 a.m. and 12.50 a.m. one bright Leonid was 

 seen, two probable Leonids, and four sporadic meteors. 



Mr. J. K. Henry, writing from Dublin, says " there was a 

 di.stinct display here of meteors from the Leonid radiant on the 

 morning of November 15. During a watch kept from 10.20 to 

 II. 15 on the night of November 14 only three meteors of the 

 first or second magnitude were observed. The first was a fine 

 bolide which passed a few degrees to the right of Gemini 

 towards Leo at about 10.55. The watch was resumed at 12 

 o'clock under somewhat restricted conditions as regards position, 

 which faced the east. From i to 3.30 meteors shot steadily 

 from the Sickle at the rate of about twelve per hour for those of 

 the first or second magnitude. No sporadic shooting stars 

 above the third magnitude were noted in this part of the sky. 

 The brightest meteor, equal to Sirius, was observed at 2.40 a m. 

 It passed somewhat slowly from the Sickle to a position 20° 

 below Procyon. A brilliant flash illuminated the eastern 

 horizon at 3.30 a.m." 



Motion ok the Gre.\t Red Spot on Jupiter. — In 

 Popular Astronomy, vol. ix. pp. 44S-490, Mr. W. F. Denning 

 discusses the observations secured of the position of the great 

 red spot during the period 1S94-1901, illustrating the result 

 by a curve showing the drift in longitude of about 50" in that 

 time. An observation made on 1901 September 5 is interesting 

 from the fact that it was exactly seventy years after that of 

 1830 September 5, when H. Schwabe at Dessau first drew the 

 hollow. During this interval of 2,208,980,280 seconds the 

 planet has made 61,813 rotations, giving a mean period of gh. 

 55m. 36-56S. 



The observations at Bristol have mostly been made with a 

 power of 312 on a lo-inch reflector. 



