no 



NA TURE 



[November 30, 189^ 



been published by Messrs. J. and A. Churchill. Mr. A, G. 

 Bloxam, the editor of the new edition, has made several im- 

 portant additions and alterations, and these changes will doubtless 

 enable the book to retain its high position among the many 

 works that now exist on practical chemistry. 



What are happily termed " Drum-and-trumpet Histories" 

 have not been so numerous since the publication of the late Mr. 

 Green's famous narration of the development of the English 

 people. A more pretentious work of a similar kind is " Social 

 England," edited by Dr. H. D, Traill, and published by Messrs. 

 Cassell and Co. In this history a section of each epoch is devoted 

 to a description of the conditions of science and learning, and 

 another to trade and industry. The departure cannot be too 

 highly commended, for the truest epic of a nation's life is that in 

 which the interests of all classes are recited. 



Lanternists will be glad to learn that Messrs. Perken, 

 Son and Rayment have introduced a new oil-lamp, possessing 

 three times the candle-power of those hitherto used for lantern 

 projection. This gain of brilliancy is obtained by dividing the 

 oil reservoir, so as to provide central air-shaft. The combustion 

 is thus rendered more perfect, and the odour that usually accom- 

 panies ordinary lamps is correspondingly decreased. For small 

 audiences the lamp will suit a lecturer's purpose quite as well as 

 the lime-light. Doubtless the recent fatal result of the break- 

 ing of an oxygen cylinder at Bradford will considerably increase 

 the demand for perfected lamps of this kind. 



The success of Sir John Lubbock's book on " The Beauties of 

 Nature " has induced Messrs. Macmillan to issue a cheap 

 edition, without illustrations. Though the book possesses a 

 good table of contents, its value would be increased by the 

 addition of an index. The author will be glad to have his atten- 

 tion called to one or two slips. On p. 207, Jupiter is said to 

 have four satellites, whereas Prof. Barnard's discovery has 

 brought the number up to five. Nitrogen should be removed 

 from the list of elements in comets (p. 213), and Clarke (p. 223) 

 should be Gierke. These slips, however, are but spots on the 

 sun, for there are few books that will enlighten the general 

 reader more than the one before us. 



A REMARKABLE new substance, i^ocyanogen tetrabromide, 

 Br2C = N- N:=CBr„, has been obtained by Dr. Thiele in the 

 laboratory of the Munich Academy of Sciences, and an account 

 of it is contributed to the current Berichte. It was prepared by 

 the reduction of azotetrazine, anew substance very rich in nitro- 

 gen (concerning which Dr. Thiele promises a further communi- 

 cation), and by treatment of the reduction product, hydrazotetra- 

 zine, with bromine. Isocyanogen tetrabromide is readily vola- 

 tile in steam, insoluble in water, but soluble in organic solvents, 

 particularly in ether. It crystallises from glacial acetic acid in 

 large prisms, which rapidly lose their brilliancy, however, upon 

 removal from the mother-liquor. The crystals melt at 42^, 

 emitting a most pungent, irritating odour. The crystals nor- 

 mally in the cold evolve the same odour, although not so strongly 

 as when warmed. Concentrated sulphuric acid, at the tem- 

 perature of a water-bath, rapidly dissolves them with produc- 

 tion of hydrazine and evolution of carbon dioxide, hydrobromic 

 acid, and smaller quantities of free bromine and sulphur dioxide. 

 Water precipitates from this solution a large quantity of hydra- 

 zine sulphate, which may easily be identified by its melting- 

 point (256°), its reduction of silver solutions, and its formation of 

 a difficultly soluble double sulphate with copper sulphate. The 

 reaction for the decomposition by sulphuric acid is probably as 

 follows : 



Br2C = N-N = CBr2-f4H20 = 4HBr4-2C02-t-N2n4. 

 Dilute hydrochloric and sulphuric acids only attack the tetra- 

 bromide after long-continued heating to 300"=, the former then 

 converting it into nitrogen and ammonia, and the latter oxidising 



NO. 1 257. VOL. 49] 



it. Its reaction with alkalies is specially interesting. It dissolves 

 readily in them, and upon subjecting the alkaline liquid to dis- 

 tillation another new compound, which is probably isocyanogen 

 oxide OC = N-N=:CO or a polymer of that substance, passes 

 over with the last portion of distillate. If a reducing agent, . 

 such as alcohol, a ferrous, manganous or stannous salt, is added 

 to the alkaline solution, a powerful odour of the well-known 

 isonitrile kind is at once emitted. This same odour is produced 

 when the alcoholic solution of the tetrabromide is decomposed 

 with zinc dust and a little chloride of zinc. It appears most 

 probable that the odour is due to the hitherto unisolated isocy- 

 anogen, C = N - N = C. The supposition is further justified by 

 the fact that the strongly odourous substance is expelled by boil- 

 ing in a current of carbon dioxide, and i? capable of absorption 

 by hot dilute sulphuric acid with formation of a solution of just 

 such powerfully reducing proclivities as might be expected from 

 a solution of hydrazine and formic acid. 



The first results of an important research in connection with 

 the melting-points of the more refractory inorganic salts are 

 likewise communicated to the current Berichte by Prof. Victor 

 Meyer and Dr. Riddle. The observations have been made with 

 the object of ascertaining the relations of the melting-points o' 

 definitely connected salts, those already investigated being the 

 chlorides, bromides, and iodides of sodium and potassium, and 

 the sulphates of those metals. The method adopted in order to 

 measure such high temperatures witn accuracy was essentially as 

 follows : — The salt was heated considerably above its melting- 

 point in a capacious platinum crucible, by means of a Perrot 

 furnace. The crucible was then removed from the furnace, and 

 an air thermometer, constructed of platinum and on the compen- 

 sating principle, was inserted into the liquid salt. As soon as 

 solidification of the latter commenced the temperature remained 

 constant for some little time, quite sufficient to enable the air, or 

 in the cases of very high melting-points, the nitrogen contained 

 in the thermometer, to be displaced by hydrochloric acid gas, and 

 its volume measured over water. The results obtained are the 

 following : — The chloride, bromide, and iodide of sodium melt 

 at 851°, 727°, and 650°, respectively ; the analogous salts of 

 potassium fuse at 766°, 715°, and 623°. In each case a lower- 

 ing of the melting-point accompanies the increase of the atomic 

 weight either of the halogen or of the metallic element. Potash 

 (presumably the oxide) melts at 1045", and soda at 1098°, the 

 same rule again applying. In the cases of the sulphates, however, 

 sodium sulphate is found to melt at 843°, and potassium sulphate 

 at the much higher temperature of 1073°, a result contrary to 

 the rule for the halogen salts, but which is quite in keeping with 

 other well-known diff"erences which the oxy-salts of sodium and 

 potassium exhibit. 



The additions to the Zoological Society's Gardens during the 

 past week include a Chacma Baboon {Cynocephahis porcarlus, 

 i ) from South Africa, presented by Mr. W. S. Cox ; two 

 Common Marmosets [Hapale jaccJms) from Brazil, presented by 

 Dr. S. Steggall ; a Pallas' Goat {Capra cylindricornis, 9 ) from 

 the Caucasus Mountains, presented by Mr. H. H. P. Deasy ; 

 a Duyker Bok {Cephalophiis inerge7ts, i ) from South Africa, 

 presented by Miss Gertrude A. Winiy ; three Palm Squirrels 

 {Sciuriis pahnarum) from India, presented by Mrs. S. W. 

 Maclver ; a Meyer's Parrot [PcEocephalus meyeri) from South 

 Africa, presented by Mrs. B. Searelle ; a Great Eagle Owl 

 {Bubo maximus) from China, presented by Major Boyd Bredon; 

 two Puffins {Ftatercula arctica) British, presented by Mr. E. 

 Hamond ; a Brown Capuchin {Cebus fatuelhis, 6 ) from Brazil, 

 a Rhesus Monkey (Macacus rhesus, ? ) from India, six Meyer's 

 Parrots {Paocephalus meyeri), an Alario Sparrow (^Passer alario) 

 from South Africa, deposited; two RtdiShaxiVs {Totamts calidns), 

 British, purchased. 



