October 4, 1894] 



NA TURE 



555 



The Society for Promoting Christian Knowledge have just 

 l)rought out a second edition of "Our Secret Friends and 

 Foes," by Pr.f Percy Frankland, F.R.S. It will be 

 •inembered that the volume was the source of a good deal of 

 iiscussion between some members of the Society, who, with the 

 ite Lord Coleridge at their back, announced their intention of 

 retiring from their membership unless the book was withdrawn 

 fr )m circulation, it being, according to their interpretation, 

 written in support of vivisection. That the Society did not 

 yield to the very considerable pressure brought to bear upon 

 them is evidenced by the appearance of the second edition, 

 .vliich, whilst containing an entirely new chapter on the action 

 of light on micro-organisms, remains otherwise, with the 

 exception of a few (mostly verbal) altentions, unchanged. 



Messrs. Ciiap.man and Hall will publish, almost imme- 

 diately, a complete "Text-book of Mechanical Engineering," 

 ■ly Mr. W. J. Lineham, the Head of the Engineering Section 

 .f the Goldsmiths' Institute, New Cross. The work consists 

 'f nearly eight hundred pages and more than seven hundred 

 ■ .;ures. The first half is devoted to practical work, viz. easi- 

 ly and moulding, pattern-making, and casting design ; 

 netallurgy and properties of materials ; smithing and forging ; 

 machine tools ; marking off; fitting, machining, and erecting'; 

 I liler-making and plate-work. The second part of the book 

 leals with theory and examples, the order of treatment being 

 length of materials ; energy and the transmission of power to 

 n.ichines and heat engines ; hydraulics and hydraulic machines. 

 I'he book is not supposed to be an exhaustive treatise on 

 mechanical engineering ; nevertheless, it will be a valuable aid 

 ! > engineering students and apprentices, and engineering 

 draughtsmen generally. 



Since the publication of "Forthcoming Scientific Books' 

 111 our issue of September 20, the following list of announcements 

 lias been sent to us by the Cambridge University Press : — 

 • The Scientific Papers of John Couch Adams "; "A Treatise 

 on Spherical Astronomy, " by Prof. Sir Robert 3. Ball, F.R.S. ; 

 'Hydrodynamics: a Treatise on the Mathematical Theory of 

 :lie Motion of Fluids,'' by Prof. H. Lamb, F.R.S., new edition ; 

 ■ Catalogue of Scientific Papers compiled by the Royal Society 

 if London, " new series for the years 1S74-83, vol. xi. in the 

 press; " .\ Treatise on Geometrical Optics," by R. A. Her- 

 man; "An Introduction to Abel's Theorem and the allied 

 Theory," by H. F. Baker; " A Treatise on Geometrical Conies,'' 

 by F. S. Macaulay ; "An Elementary Introduction to Miner- 

 alogy," by R. H. Solly ; " Euclid's Elements of Geometry," 

 Books .\[. and XH., by H. M. Taylor; "Arithmetic for 

 Schools," by C. Smith, with or without answers, second 

 edition ; " Key to C. Smith's .Arithmetic " ; " Practical Physio- 

 logy of Plants," by F. Darwin, F.R.S., and E. H. .Vcton ; 

 " Practical Morbid .\natomy," by Dr. H. D. RoUeston and 

 Dr. A. A. Kanthack ; " The Distribution of Animals," by 

 F. E. Beddard, F.R.S. ; " Petrology," by A. Harker ; " Text- 

 tiook of Physical .Vnthropology, " by Prof, .\lexaader Macalister, 

 F.R.S.; "The Vertebrate Skeleton," by S. H. Reynolds; 

 " Fossil Plants : a Manual for Students of Botany and Geo- 

 logy," by A. C. Seward ; " Elements of Botany, " by F. 

 Darwin, F.R.S.: "Mechanics and Hydrostatics,"' by R. T. 

 Glazebrook, F.R.S. ; "Electricity and Magnetism," by the 

 same author. 



Messrs. Charles Grii-i'IN a.nd Co. have also sent 

 a list of the scientific books they hope to issue during the 

 ensuing season; it is as follows : — "Petroleum,"' a treatise on 

 the geographical distril>ution, geological occurrence, chemistry, 

 production, and refining of petroleum ; its testing, transport, 

 and storage, and the legislative enactments relating thereto, to- 



NO. I 30 1, VOL. 50] 



gether with a description of the Shale Oil industry, by Boverton 

 Redwood, assisted by Geo. T. IIoIlow.ay, with map; and illus- 

 trations ; "Calcareous Cements: their Nature, Preparation, 

 and Uses," with some observations on cenent testing, by Gilbert 

 R. Redgrave ; "Griffin's Chemist's Pocket-book " : tabler and 

 data for analysts, chemical manufacturers, and scientific chemists, 

 by J. Castell-Evans ; " Measurement Conversions" (English and 

 French), 2S graphic tables or di<igram?, showing at a glance the 

 mutual conversion of measurements in different units of length, 

 areas, volumes, weights, stresses, densities, quantities of work, 

 horse powers, temperatures, &c., for the use of engineers, sur- 

 veyors, architects, and contractors, by Prof. Robert. Henry 

 Smith ; " The Metallurgy of Iron," by Thomas Turner ; " An 

 Elementary Text-book of Metallurgy," for the use of younger 

 students and those commencing the study of metallurgy, by 

 Prof. A. Humboldt Sexton, with numerous illustrations ; 

 "Kitchen Boiler Explosions: why they occur, and how to 

 prevent their occurrence," a practical hand-book, based on 

 actual experiments, by R. D. Munro ; " Fibroid Diseases 

 of the Lung, including Fibroid Phthisis," by the late Sir 

 Andrew Clark, Bart., F.R.S., and Drs. W. J. Iladley 

 and .\rnold Chaplin, with tables, and eight plates in colours ; 

 " Practical Hygiene," including air and ventilation, water, 

 supply and purity ; food and the detection of adulterations, 

 sewage removal, disposal, and treatment, epidemics, &c., 

 by Surgeon-Major A. M. Davies, with illustrations; "A 

 Manual of Ambulance," by J. Scott Riddell, with 

 numerous illustrations and full-page plates ; " The Hand- 

 Rearing of Infants : a Guide to the Care of Children in Early 

 Life," by Dr. John Benj. Hellier; "Year-book of the 

 Scientific and Learned Societies of Great Britain and Ireland," 

 compiled from official sources, including lists of the papers read 

 during 1894 before Societies engaged in fourteen departments of 

 research. Twelfth annual issue (early in 1S95). 



O.ne of the most striking features of chemical progress at the 

 present time is the rapid advance which is being effected in our 

 knowledge of the compounds of nitrogen, .\nother com- 

 pound of primary importance, symmetrical hydrazo-ethane, 

 C.jHsNH. NHC„H,, the symmetrical di-ethyl derivative of 

 hydrazine, has been isolated in the laboratory of the Berlin 

 Univer.^ity by Dr. Harries. Prof Emil Fischer has already ob- 

 tained the unsymmetrical di-ethyl hydrazine, and Prof. Curtius, 

 to whom we owe the discovery of hydrazine itself, some lime 

 ago succeeded in obtaining the symmetrical di-benzyl hydrazine, 

 but hitherto the simple symmetrical fatty hydrazines have eluded 

 isoLation. Indeed it is only by a somewhat circuitous, although 

 practically quite easy, series of reactions that symmetrical di- 

 ethyl hydrazine has at length been prepared. \ remarkable 

 derivative of hydrazine was first obtained, in which one 

 hydrogen of each amidogen radicle w.as replaced by the radicle 

 formyl, CHO, and the other by the metal lead, the compound 



CHO— N— N— CHO. 

 being represented by the formula \ / This 



Pb 

 substance, a white powder, is readily obtained by reacting with 

 sodium upon di-formyl hydrazine, a compound with which 

 Prof. Curtius has made us familiar, and subsequently decom- 

 posing the latter with sugar of lead. The lead compound, 

 when slightly heated in a sealed tube with ethyl iodide, 

 together with sand to maintain porosity, and m.agnesia to fix the 

 liberated hydriodic acid, is converted into a compound in which 

 the lead atom is replaced by two ethyl groups. This latter 

 compound, a somewhat volatile liquid, is treated with fuming 

 hydrochloric acid, which removes the formyl groups and con- 

 verts the compound into symmetrical di-ethyl hydrazine hydro- 

 chloride, which is precipitated. Upon distillation with caustic 

 potash the free di-ethyl hydr.i.!inc passes over at 85°. The new 



