Feb. 28, 1889] 



NA TURE 



4^9 



elapsed. In but a few days after the re-issue of the books the 

 children began to come down with measles. There can be little 

 doubt that scarlet fever is transmitted in the same way." 



Sir Henry Peek has compiled an interesting catalogue of 

 his collection of birds at Rousdon. The catalogue consists of 

 two parts. The first is accompanied by an outline index plate 

 of each case, by means of which one may identify every bird in 

 the case, and find out its name and some other details regarding 

 it, by consulting the list. The second part consists of an alpha- 

 betically arranged list of both the English and the scientific 

 names of every bird, with reference to its case, compartment, 

 and number on the index plate, so that any particular bird 

 required may be found without difficulty. The index plates, as 

 Sir Henry Peek points out in the preface, save the necessity of 

 affixing labels or numbers to the birds, which would have 

 interfered with the artistic appearance of the groups. 



Under the title " The True Position of Patentees," Mr. H. 

 Moy Thomas has published, through Messrs. Simpkin, Marshall, 

 and Co., a little book in which the patent laws and regulations 

 at home, abroad, and in our colonies and dependencies, are 

 explained for the information of English inventors. 



Messrs. Macmillan and Co. will publish in September the 

 Eleventh Book of Euclid, Propositions 1-2 1, with alternative 

 proofs, exercises, and additional theorems and examples, by Mr. 

 F.H. Stevens, of Clifton College, joint editor of Hall and Stevens's 

 Euclid, Books i.-vi. Later on it is the intention of Mr. Stevens 

 to issue a book on elementary solid geometry and mensuration, 

 containing the matter included in the above-mentioned volume, 

 w ith a section on polyhedrons and solids of revolution, treated 

 geometrically and numerically, with exercises on the mensuration 

 of plane and solid figures. 



Messrs. Longmans and Co. have in the press " A Hand- 

 book of Cryptogamic Botany," by A. W. Bennett and George 

 Murray. No general hand-book of Cryptogamic botany has 

 appeared in the English language since Berkeley's, published in 

 1857. The ])resent volume will give descriptions of all the 

 classes and more important orders of Cryptogams, including all 

 the most recent discoveries and observations. 



A number of remarkable salts of hydrazine or amidogen 

 have been prepared by Drs. Curtius and Jay, in the course 

 of their work upon the hydrazine compounds, which has so 

 successfully resulted, as noticed in these columns a fort- 

 night ago (p. 377), in the isolation of the hydrate of amidogen, 

 N.2H4 . H2O. Amidogen, as indicated by the strong alkalinity 

 of its hydrate, and by the well-known reactions of its organic 

 substitution-products, is a powerful base, and combines with 

 acids to form salts of considerable stability at ordinary temper- 

 atures. Perhaps the most interesting of these salts, and the one 

 utilized for the preparation of the liquid hydrate itself, is the 



NH2 . HCl 

 di-hydrochloride, | . This salt possesses a most strik- 



NH2 . HCl 

 ing resemblance to ammonium chloride, crystallizing in the cubic 

 system, and depositing, on rapid evaporation, in the same beauti- 

 ful feathery forms. It diffisrs, however, from ammonium chloride 

 in being very deliquescent. When heated to 198" C, it fuses, 

 with evolution of hydrochloric acid, to a clear glass consisting 



NHj. HCl 

 of the mono-hydrochloride, | . On further heating to 



NHj 

 240°, it is entirely decomposed, with evolution of free nitrogen 

 and hydrogen and sublimation of ammonium chloride — 

 NHj . HCl 

 2 I = 2NH4CI -I- Nj + H, + 2HCI. 



NH2 . HCl 



Contrary to the usual behaviour of bases of the ammonium type, 

 platinum chloride in acid solution gives no platinochloride ; the 



reducing action comes so violently into play that the platinic 

 salt is reduced to platinous chloride, with copious evolution of 



NHj 

 nitrogen gas. The sulphate, | . H2SO4, like ammonium sul- 



NH2 

 phate, is anhydrous, and crystallizes in optically biaxial prisms. It 

 is the most insoluble of the hydrazine salts in cold water, and is 

 precipitated from cold solutions of all the other investigated salts 

 by dilute sulphuric acid ; it readily dissolves, however, in hot 

 water. On heating it melts at 254° with explosive evolution of 

 gas, breaking up into ammonium sulphite, sulphurous acid, 

 sulphuretted hydrogen, and, most remarkable of all, large 

 quantities of free sulphur. The carbonate is obtained by saturat- 

 ing a solution of the hydrate with carbonic acid gas, and evapor- 

 ation in vacuo as a highly deliquescent mass. The nitrate can 

 readily be obtained from the carbonate by treatment with nitric 

 acid ; it crystallizes well, and is also extremely soluble. The 

 acetate and oxalate have also been obtained in fine crystals. All 

 these salts possess the same exceptional reducing powers, free 

 nitrogen and water being formed in the process. They all de- 

 compose on heating with formation of salts of ammonium, and of 

 gaseous nitrogen and hydrogen. One of their most important 

 properties is their reaction with nitrous acid ; on mixing any salt 

 of hydrazine with a salt of nitrous acid, free nitrogen is evolved 

 with almost explosive violence. It is finally of considerable 

 significance that those which crystallize well appear to be 

 isomorphous with the corresponding ammonium salts. 



A Belgian, M. Nizet, of the Royal Library of Brussels, 

 proposes to issue a periodical catalogue or table of all papers 

 published in all the periodicals in the world. Of course the 

 titles of the papers are to be methodically grouped under a certain 

 number of divisions. 



The following are the arrangements for science lectures at 

 the Royal Victoria Hall during the month of March : — Tues- 

 day, March 5, "A Visit to the Moon : how we got there and 

 what we saw," by Prof. Carlton Lambert ; Tuesday, March 12, 

 "A Tramp among the Mountains at Home and Abroad," by 

 Prof. Kennedy, F.R.S. ; Tuesday, March 19 and 26, two lec- 

 tures, by Prof, H. E. Armstrong, on the " History of a Crime 

 unravelled by a Piece of Rusting Iron, a Horse-shoe, and a 

 Match." 



The Indian Forester, in a review of the work of the Forest 

 Department under the rule of Lord Dufferin, says that the total 

 number of prosecutions for offences against the forest laws has 

 been steadily diminishing. The area under protection from 

 fire has risen from 15,570 to 18,691 square miles. Large areas 

 have been withdrawn from nomadic grazing ; and, generally 

 speaking, the old and wasteful methods have been displaced by 

 an entirely new system, which is only now making itself felt. 

 The influence of forest conservancy on the rainfall, the tem- 

 perature, and the water-supply is becoming appreciated by the 

 people of India. Large additions have been made to the teak 

 plantations of Burma, and great quantities of mahogany have 

 been planted at Nilambur. The revenue has risen from 67 lacs 

 in the years 1876-80, to 94 lacs during the viceroyalty of Lord 

 Ripon, and to 116 during that of Lord Dufferin. These figures 

 do not include the money received from Upper Burma, where 

 the loosely-drawn leases have given infinite trouble to the 

 officials. The staff is too weak for the work, but a re- 

 organization scheme is under consideration. The forest class 

 at Cooper's Hill, and the working of the Dehra Dun School, 

 will no doubt improve the standard of knowledge of the 

 officials. 



In the recent Report of the Bombay Chamber of Commerce it 

 is said that the opinion of the Chamber was solicited as to the 

 advisability of introducing a uniform standard of weight through- 



