January 25, 1894] 



NATURE 



299 



The number of the Victorian Naturalist iorViecemhtx, 1893, 

 affords evidence of the activity of the study of various branches 

 of natural history in that colony. 



We have received a paper, reprinted from the Canadiaii 

 Record of Science, October, 1893, in which Mr. J. F. Whiteaves 

 gives descriptions of two new species of ammonites from the 

 Cretaceous rocks of the Queen Charlotte Islands. 



Dr. J. Bergeohm has sent us apamphlet entitled " Entwurf 

 einer neuen Integral-rechnung," Heft ii., in which he develops 

 a new method for the calculation of integrals, and deals with 

 irrationals, exponentials, logarithmic and cyclometric integrals, 

 using his system. 



Messrs. C. Griffix and Co. have 'published a "Pocket- 

 Book of Marine Engineering Rules and Tables, " for the use of all 

 engaged in the design and construction of marine machinery, 

 naval and mercantile. The authors of the book are Mr. A. 

 E. Seaton and Mr. H. M. Rounthwaite. 



To those who purpose a tour in the Bernese Oberland, we 

 can specially recommend a series of papers published in the re- 

 cent numbers (211-214) of Eiiropdische Wanderbilder (Zurich, 

 1893.) They are written by F. Ebersold, and give a general 

 sketch of the country, as well as information about the new 

 mountain-railways. 



Bulletin No. 46 of the U.S. National Museum contains the 

 collected writings, both published and unpublished, of the late 

 Mr. C. H. BoUman, on the Myriapoda of North America. The 

 papers have been edited by Prof. L. M. Underwood, who has 

 added some notes and an introductory review of the literature 

 of the North American Myriapods. 



We are pleased to see that the Yorkshire Weekly Post is now 

 publishing weekly a well-written and accurate article dealing 

 with the different branches of natural history, and in which the 

 subject of ornithology and entomology in relation to agriculture 

 is dealt with in a practical manner ; miscellaneous science notes 

 are also included, and their sources properly acknowledged. 



The "School Calendar and Handbook of Examinations and 

 Open Scholarships,'' published by Messrs. Whittaker and Co., 

 is now in its eighth year of issue. The book contains a mass of 

 information concerning the conditions of entrance scholarships 

 and fees in all our Public Schools, Universities, and educational 

 institutions, and is invaluable to the schoolmaster and teacher. 



A SECOND edition, revised and enlarged, has been issued of 

 the Guide to Museum No. IH. of Economic Botany at the 

 Royal Gardens, Kew. The collection in this museum chiefly 

 consists of specimens of timber, arranged in groups according 

 to the countries producing them. The Guide contains much 

 usetul information with regard to the scientific character and 

 economic value of the specimens. 



Messrs. Macmillan and Co. hope to publish in a few days 

 " The Theory of Heat," by Mr. Thomas Preston, Professor of 

 Natural Philosophy, University College, Dublin. In this 

 volume the science of heat is treated in a comprehensive 

 manner, both in its experimental and theoretical aspects. The 

 whole subject has been kept in view rather than the require- 

 ments of a particular examination, and the method of exposition 

 is such that the general reader will be interested as well as the 

 specialist. 



TwE. nvivahtr oi A}imiario publicaJo pelo Observatorio do Rio 

 de Janeiro, which we have recently received, is the ninth that 

 has been published, and is for the year 1893. In addition to 

 various ephemerides and astronomical data, the volume contains 

 some useful metereological tables with data relating to the 

 climatology and physics of the globe, tables for calculating 

 altitudes from barometric observations, vapour tension, and 

 several others for the use of physicists and those engaged in 

 NO. 1265, VOL. 49] 



chemistry. The fifth and concluding part gives the latitude 

 and longtitude of the chief places in Brazil, with the heights 

 in metres of the chief cities above the sea-level, terminating 

 with a brief sketch of the climate of Brazil in general. The 

 tables seem all to have been carefully constructed and brought 

 up to date. 



"A History of Scandinavian Fishes," by B. Fries, C. 

 U. Ekstrom, and C. Sundevall, with coloured plates by W. von 

 Wright, made its first appearance in 1836, and though it was 

 issued in an incomplete form, it gained a wide reputation. As 

 several unpublished paintings by v. Wright were preserved in the 

 archives of the Royal Swedish Academy of Science, and the 

 text of the work could be brought up to date with comparatively 

 slight alterations, Messrs. Sampson Low, Marston, and Co. 

 have decided to issue a new edition. The work of revision and 

 enlargement has been entrusted to Prof. F. A. Smitt, the 

 present occupier of Sundevall's post at the Royal Zoological 

 Museum. The former edition contained descriptions and figures 

 of 64 species ; the new one will comprise about 220 Scandina- 

 vian species, besides several forms from neighbouring parts, and 

 of special interest to the Scandinavian faunist. Thus the great 

 majority of the fishes of Europe as well as of the Arctic piscine 

 species will be represented in the work, and the new edition will 

 be about four times as comprehensive as the former one. 



The interesting di-nitro derivative of marsh gas, CH2(N02)2 

 has been isolated in the pure state by Dr. Paul Duden, in the 

 chemical laboratory of the University of Jena. As might be ex- 

 pected, it is a substance of little stability, and many of its 

 metallic derivatives or salts, for the parent substance is endowed 

 with acid properties, are dangerously explosive. The compound 

 itself cannot be preserved, even in sealed tubes, for many 

 hours, becoming converted into gaseous products of decomposi- 

 tion, but its potassium salt, CHK(N02)2, is much more stable, 

 and may be kept unchanged for months. The preparation of 

 the acid is best achieved from this potassium salt, by decompos- 

 ing it at a low temperature with dilute sulphuric acid. The 

 potassium salt may be readily obtained by reducing the di- 

 bromine derivative of dinitromethane by means of an alkaline 

 solution of arsenious oxide. The di-bromine derivative is a 

 substance obtained by distilling tribromaniline with nitric acid. 

 It is added in small portions at a time to the strongly-cooled 

 aqueous solution of the alkaline arsenite, in order to mitigate 

 the violence of the reaction. After the completion of the 

 change the potassium salt is deposited in small bright yellow 

 crystals, which by recrystallisation from hot water yield the salt 

 in perfectly pure large monoclinic prisms. The aqueous solu- 

 tion of these crystals is neutral to litmus, the strong acid being 

 neutralised by the introduction of one atom of potassium. At 

 a temperature near 205° the crystals detonate loudly, evolving a 

 mixture of nitrogen, nitric oxide, and carbon dioxide. Concen- 

 trated acids violently decompose the crystals with evolution of 

 red nitrous fumes, but if they are suspended in iced water, and 

 a layer of ether is spread over the surface, they are quietly acted 

 upon by dilute sulphuric acid with liberation of free dinitro- 

 methane, as above mentioned. The latter substance is dissolved by 

 the ether, and the dried ethereal solution yields it after evapora- 

 tion of tha ether as a yellowish liquid of peculiar acid odour, 

 and which soon begins to effervesce, owing to the elimination of 

 products of decomposition. The free compound may be pre- 

 served much longer in ethereal or benzene solution. The silver 

 salt, CHAg(N02)2, is the most remarkable of its salts. It crystal- 

 lises in bright green tabular crystals, which are extremely sensi- 

 tive to light. Mere boiling of their aqueous solution is suffi- 

 cient to produce deposition of metallic silver. Either upon 

 warming or by contact with a drop of hydrochloric acid, the 

 crystals explode with great violence. Upon reduction of the 

 iced solution of the potassium salt by sodium amalgam, a curious 



