566 



NATURE 



[April 13, 1893 



of 40 cm., and was so hot that the observer was unable to put 

 his hand on it. At the explosion of the meteor several small 

 portions weij^hing from 30-60 gr. were scattered, while the 

 weight of the chief mass amounted to 22 kg The description of 

 the exterior says that it showed the general, smooth, black crust, 

 while from the fracture it was noticed to be finely granulated ; 

 one could also see easily small particles of iron, which could 

 without any difficulty be separated by pulverisation. Chemical 

 analysis showed that nickel and cobalt was present in consider- 

 able quantities. 



Jahrbuch dkr Astronomie und Geophysik. — This 

 volume, which is edited by Dr. Hermann J. Klein, contains a 

 very interesting account and summary of the work done in 

 various branches of astronomical science during the past year. 

 Duner's, Deslandres', Hale's, and Young's sun observations 

 are referred to, while several other references to solar work are 

 given. The numerous observations made with reference to the 

 major and minor planets are here all brought together ; Trou- 

 velot's Venus observations, the opposition of Mars, and the 

 recent discovery of Jupiter's fifth satellite being rather prom- 

 inent. Under the heading of " The Moon" Wernik's enlarge- 

 ments, Boddiker's and Hartmann's researches and are referred 

 to at some length. Comets, meteorites, and shooting stars also 

 come in for a good share, and under the fixed stars, in which are 

 included all variables, nebulae, &c., are included references to the 

 Nova in Auriga, stellar spectroscopic observations, motion in 

 line of sight, &c. 



The Ouservatory. — From the cover of the Observatory ont 

 quite misses the familiar name of Dr. Common, in place of 

 which are now inserted Messrs. T. Lewis and H. P. Hollis. 

 In an editorial notice Mr. Turner says a few words to account 

 for this perturbation, mentioning that it is owing to pressure of 

 work, which has made it impossible for either of them to con- 

 duct the magazine. He concludes by saying, " It would be with 

 the keenest satisfaction that we should return to the manage- 

 ment of the magazine if the future should have that in store for 

 us." 



GEOGRAPHICAL NOTES. 



The Scottish Geographical Magazine for April contains a 

 paper of some value by Colonel Justin C. Ross on irrigation 

 and agriculture in Egypt, giving the result of his experience as 

 Director-General of Irrigation in that country. In consequence 

 of the indisposition of Colonel Bailey the Magazine is now 

 edited by Mr. W. A. Taylor, Librarian to the Royal Scottish 

 Geographical Society, who has for several years had charge of 

 the book reviews and geographical notes. 



The April number of the Deutsche Rundschau fiir Geographie 

 contains a coloured map of the density of population in Holland 

 which illustrates in a manner very rare in continental map-work 

 an ignorance of the first principles of map colouring. The objects 

 of map-colouring are two — one is to indicate the areas occupied 

 by discontinuous and unlike conditions, such as countries, races of 

 people, or geological formations. For this the colours have to be 

 as strongly contrasted as possible and the map is necessarily and 

 properly a patchwork. The other object is to show the dis- 

 tribution of a continuously varying quantity, like altitude, 

 temperature, or rainfall, and in order to attain it the colours 

 ought to merge one into the other so that the eye is carried 

 from the lowest to the highest value by just perceptible grada- 

 tions. The Austrian map referred to applies the first method 

 to bring out the second result, each different density of popula- 

 tion being coloured so as to contrast with the others, and to show 

 no definite gradation from less to greater. 



Globus states that the Russian Government, dissatisfied with 

 the foreign sound of the names Dorpat and DUnaburg, have 

 resolved to rename those towns Jurjew and Dwinsk respec- 

 tively. 



The Paris Geographical Society held a special meeting in 

 commemoration of the discoveries of Columbus on March 4, 

 the four hundredth anniversary of his return from the first trans- 

 atlantic voyage. A masterly address by M. Levasseur on the 

 moral and material consequences of the discovery of America, 

 and a paper by ^r. Hamy on the traces of Columbus in Spain 

 and Italy were the principal features of the meeting. 



NO. 1224, VOL. 47] 



Some recent measurements in Russia, noticed by M. VenukofF 

 in the last number of the Comptes Rendus are valuable as lead- 

 ing to some conclusions regarding the form of the geoid. 

 Determinations of the value of the degree of longitude along the 

 parallels of 47°3o' and 52° accord closely with Bessel's geoid 

 (polar flattening ..^.j) and are widely divergent from Clarke's 

 result of ,,',.. 



THE AMIDE AND IMIDE OF SULPHURIC 

 ACID. 



"PURTHER details concerning these interesting substances 

 ^ are communicated by Dr. Traube of the laboratory of the 

 Berlin University to the current number of the Berichte It has 

 long been surmised that an amide of sulphuric acid was capable 

 of existence, and Regnault assumed that the product which he 

 obtained by leading ammonia gas into a solution of sulphuryl 

 dichloride in ethylene chloride consisted of that substance 

 mixed with sal-ammoniac. Dr. Traube has further investigated 

 the reaction and has at length isolated not only sulphuryl dia- 

 mide, S02(NH2)2, but also sulphuryl imide, SOoNH, the imide 

 of sulphuric acid, and has, moreover, prepared several metallic 

 derivatives of each. 



Sulphuryl Diamide. 

 The most advantageous mode of preparing sulphuryl diamide 

 consists in saturating a solution of sulphuryl dichloride, SO^CIo, in 

 chloroform with ammonia. It is necessary to dilute the sulphuryl 

 dichloride with 15-20 times its volume of chloroform, and to 

 maintain a low temperature by extraneous cooling in order that 

 the reaction may be under complete control, and the ammonia 

 gas must be carefully dried before being allowed to bubble 

 through the liquid. The main reaction occurs in accordance 

 with the foUowmg equation : — 



S0,,C1„ -J- 4NH, = 2NH4CI + SOo(NH.,),,. 



The products are gradually deposited in the form of a white 

 solid, which, after the completion of the reaction, is agitated 

 with water until the whole of it is dissolved. The ammoniacal 

 aqueous solution is then separated from the chloroform, acidified 

 with nitric acid, and the whole of the chlorine removed by the 

 addition of silver nitrate. After removal of the silver chloride 

 by filtration the acid solution is neutralised with alkali and 

 silver nitrate again added, when a crystalline precipitate is ob- 

 tained consisting of a silver derivative of sulphuryl diamide, 

 SOolNHAg)^, together with another silver compound, whose 

 composition has not yet been definitely ascertained. In order 

 to isolate the silver compound of sulphuryl diamide, the washed 

 precipitate is decomposed with the calculated quantity of hydro- 

 chloric acid, and the resulting acid liquid carefully neutralised 

 with ammonia ; upon now adding silver nitrate only the silver 

 compound of unknown and complex composition is deposited. 

 The pure silver compound of sulphuryl diamide is finally de- 

 posited upon adding a further quantity of silver nitrate and 

 sufficient ammonia to render the liquid strongly alkaline. 



When the precipitated silver compound of sulphuryl diamide 

 is decomposed with hydrochloric acid a feebly acid liquid is 

 obtained, which, when evaporated to a syrup in vacuo, at a 

 temperature not exceeding 40°, and afterwards allowed to stand 

 in vacuo over oil of vitriol, gradually deposits large colourless 

 crystals of pure sulphuryl diamide, SO-jCNH-^Jo. 



Sulphuryl diamide is an extremely deliquescent substance. 

 The crystals are rapidly dissolved by water, but are practically 

 insoluble in organic solvents. They soften at 75" and melt at 

 81°. As the liquid cools, however, it exhibits the property of 

 superfusion to a very marked extent, remaining liquid many 

 degrees below its melting-point. The moment, however, it is 

 disturbed by contact with a sharp body, it instantly solidifies. 

 When heated above its melting-point sulphuryl diamide loses 

 ammonia even below 100° ; up to 250° no further decomposi- 

 tion than the loss of ammonia occurs, the residual compound 

 being the sulphuryl imide to be presently described. Above 

 250° complete decomposition ensues with the evolution of acid 

 fumes. 



The aqueous solution of sulphuryl diamide reacts neutral to 

 litmus and possesses a bitter taste. It yields no precipitates in 

 acid solutions either with salts of barium or platinic chloride. 

 On long boiling with acids, however, it is gradually converted 

 into sulphuric acid and ammonia, and then yields the usual 



