October 6, 1892] 



NATURE 



55 



Part I. of a new work on practical physics, by Prof. W. F. 

 Barrett, of the Royal College of Science for Ireland, will shortly 

 be published by Messrs. Percival and Co. It will treat of 

 physical processes and measurements, and the properties of 

 matter. 



The University Correspondence College has issued its 

 calendar for 1892-93. The Principal, in his report, shows that 

 the college has been in many ways remarkably successful. 



The calendar of the Imperial University of Japan for 1891-92 

 affords ample evidence that the authorities of this important in- 

 stitution are doing everything in their power to secure that it 

 shall meet the needs of the present age. We may note that in 

 the college of science the following seven courses, each of which 

 extends over three years, have been established : Mathematics, 

 astronomy, physics, chemistry, zoology, botany, and geology. 



In the last sentence of the fourth paragraph of Lord Kelvin's 

 article on " Generalization of Mercator's Projection Performed 

 by aid of Electrical Instruments " (Nature, September 22, 

 p. 491), for "three" read "two." For corrections in para- 

 graph 3, and in the last paragraph but one, see article "To 

 Draw a Mercator Chart, &c,," in the present issue. 



An interesting new compound, the silver salt of the little 

 known imide of sulphuric acid, SO^NAg, has been obtained by 

 Dr. Wilhelm Traube, in the laboratory of the University of 

 Berlin, and an account of its properties, together with a con- 

 siderable amount of fresh information concerning both the amide 

 and imide of sulphuric acid, are contributed by him to the current 

 number of the Berichte. Regnault long ago obtained a solid 

 substance, which he regarded as a mixture of the neutral amide 

 of sulphuric acid SO., (NH2)2 with ammonium chloride, by 

 leading ammonia gas into a solution of sulphuryl chloride 

 S( ).,CI.3 in ethylene chloride. 



SOjCIa -1- 4NH3 =r S02(NHs)2 + 2NH4CI. 

 The separation of the two substances, however, was but imper- 

 fectly effected, so that our knowledge of the amide itself is very 

 vague. Dr. Traube now shows that the amide may be isolated 

 without difficulty by the following process. The sulphuryl 

 chloride is dissolved in fifteen times its volume of chloroform, 

 which exerts no chemical action upon it, and dry ammonia gas 

 is led through the liquid until the latter becomes saturated. The 

 products of the reaction separate during the passage of the gas 

 in the form of a white solid. The whole product is then agi- 

 tated with water until the precipitate dissolves, the aqueous 

 solution is separated from the chloroform and afterwards boiled 

 in contact with oxide of lead or silver until all chlorine is re- 

 moved from it. Upon filtering and evaporating the resulting 

 liquid a syrup is eventually obtained, which only crystallizes 

 with difficulty and would appear to consist of neutral sulphamide 

 Soo(N 112)2. It is an extremely deliquescent substance whose 

 solution in water and dilute acids is not precipitated by 

 salts of barium or by platinic chloride. Only after prolonged 

 boiling with hydrochloric acid does decomposition occur with 

 the gradual deposition of barium sulphate. The efTect of boil- 

 ing in the presence of acids would appear to be its conversion 

 into ammonium sulphate. Sulphamide possesses the power of 

 combining with the oxides of mercury, lead, and silver, to form 

 white solid substances. Thus if mercuric nitrate, lead acetate, 

 or ammoniacal silver nitrate are added to the aqueous solution of 

 the amide these white solid compounds are precipitated. The 

 mercury compound is insoluble in dilute nitric acid, while the 

 lead and silver compounds are readily soluble, forming solutions 

 which are perfectly indifferent to barium salts. It was from the 

 compound containing silver that the interesting silver imide was 

 obtained. Upon heating the silver compound to the temperature 

 NO. II 97, VOL. 46] 



of i7o°-i8o° until ammonia ceases to be evolved, and extracting; 

 the residue with hot water feebly acidified with nitric acid, the 

 new compound SOjNAg separates upon cooling in long acicular 

 crystals. Analyses have proved its composition to be that 

 stated, and from its reactions it must be regarded as being the 

 silver salt of sulphimide SOjNH. The crystals are only soluble 

 with difficulty in cold water, bat more freely in hot water and 

 readily in dilute nitric acid. The solution is noc precipitated 

 by barium nitrate. Even after removal of the silver by means of 

 hydrochloric acid barium salts yield no precipitate ; indeed, it 

 requires long boiling with concentrated acid to effect any preci- 

 pitation. It would appear that the solution left after removal 

 of the silver contains sulphimide itself, and Dr. Traube is con- 

 tinuing his experiments with a view to the isolation of the latter 

 compound. 



The additions to the Zoological Society's Gardens during the 

 past week include a Grivet Monkey {Cercopithectis gn'seo- 

 viridis 9 ) from South Africa, presented by Mr. W. Howard ; a 



Lark {Alatida calivox) from China, presented by Mr. Ger- 



vase F. Mathew, K.N., F.Z.S. ; two Common Kestrels ( 7V«- 

 nunculus alaudarius), British, presented by Mr. L..Bergasse : a 

 Herring Gall {Larus argmtatus), British, presented by Mr. H. 

 H. Johnson ; a Tuatera Lizard {Sphenodon punctatus), from New 

 Zealand, presented by Capt. G. Eriksen ; four Smooth Snakes 

 (Coronella lavis) British, presented by Mr. E. Penton, F.Z.S. ; 

 six American Green Frogs {Rana halecina), four Noisy Frogs 

 {Rana clamata), from Canada, purchased ; one Concave-casqued 

 Hombill {Dichoaros bicornis), from India, received in exchange ; 

 three Wild Swine {Sus scrofa) born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 

 Comet Brooks ( August 27, 1892). — Astronomische Nach- 

 richten. No. 31 19, contains the elements and ephemeris of 

 Brooks's comet calculated by F. Ristenpert, assuming an ellipti- 

 cal orbit and the unit of brightness on August 31 '5 as the unit 

 of Br. :— 



Elements. 



T = 1892 Dec. 28-2870 M.T. Berlin. 



« = 252 4 23 -o 

 Q, = 264 34 45-3 

 i = 24 43 17-1 

 log. <j = 9 '994 1 36 



Ephemeris for 12A. Berlin M. T. 

 g R.A. app. Decl. app. Log. r. Log. A. Br. 



Oct 6 ... 7 45 22 ... +24 47-5 



7 ... 48 30 ... 24 26-9 ... 02204 ... 0*1763 ... 371 



8 ... 51 40 ... 24 56 



9 ••• 54 SI ••• 23 436 



10 ... 7 58 4 ... 23 20.9 



11 ... 8 I 18 ... 22 57*4 ... 02077 ••• 0-1542 .. 4-35 



12 ... 8 4 34 ••• 22 33-3 



This comet on the llth inst. will be found situated in the con- 

 stellation of Cancer. It will lie very nearly on a line joining 

 the stars k Gemini and 5 Cancri, being about a third of the 

 distance nearer the former than the latter. 



Comet 1892 II, (March 18).— The following ephemeris for 

 Denning's comet we take from the Astronomische Nachrichten, 

 No. 3118:— 



12 Berlin Mean Time. 



.802. ?^- ^PP- 



^ h. m. s. 



Oct. 6 ... 6 23 9 



8 ... 22 o 



10 ... 20 43 



12 ... 19 19 



14 ... 17 48 



16 ... 16 9 



18 ... 14 23 



20 ... 6 12 29 



Decl. app. 



Log) 



Log A. 



Br. 



+ 11 54-0 

 II 6-3 ... 0-4250 ... 0-3604 ... 0-64 

 10 17-9 



9 288 ... 04300 ... 0-3539 ... 065 



8 39-1 



7 48-9 ... 0-4349 ... 0-3478 ... 065 



6 584 



6 76 ... 0-4398 ... 0-3423 ... 065 



