June 28, 1894] 



NATURE 



'05 



Society in the following year. The papers, as is well known, 

 deal with " The Decomposition of the Fixed Alkalies and 

 Alkaline Earths." Priestley's experiments in 1775, which led 

 to the discovery of oxygen, will be reprinted in No. 7, and 

 Scheele's work of 1777 in the same direction will form the 

 contents of No. 8. No. 9 will be made up of reprints of Davy's 

 papers on the elementary nature of chlorine. These three 

 volumes of the series are in the press. 



There is a certain amount of satisfaction in identifying wild 

 flowers gathered during country rambles. To assist amateur 

 botanists in and near Edinburgh to carry out this kind of deter- 

 mination, Mr. C. O. Sonntag has prepared a little book of handy 

 size, viz. "A Pocket Flora of Edinburgh and the Surrounding 

 Country," and Messrs. Williams and Norgate have published 

 it. Therein will be found, to quote the sub-title, "a collection 

 and full description of all Phanerogamic and the principal 

 Cryptogamic plants, classified after the natural system, with an 

 artificial key and a glossary of botanical terms. " It may be 

 doubted whether a student derives any great advantage from the 

 dictionary method of classifying specimens, nevertheles; he may 

 be led through such work to higher studies. Another local flora of 

 which we have received a copy is a " Vade-mecum to the Alpine 

 Flora," by L. Schriiter and Prof. C. Schniter (London ; David 

 Nutt). This book is in its fourth edition. It contains one hun- 

 dred and seventy coloured representations of Alpine flowers, so 

 that every bit of bloom which beautifies the Swiss mountain- 

 side can be easily identified by tourists without any botanical 

 knowledge whatever. No attempt is made to describe or 

 classify the plants in a systematic manner. Unlike Mr. 

 Sonntag's book, that by Prof. Schriiter appeals to the curious 

 tourist rather than the investigating student. The text is in 

 English, French, and German. 



The first edition of Quain's renowned "Dictionary of 

 Medicine " was published in 18S2 ; the second edition was issued 

 by Messrs. Longmans, Green, and Co. last week. For twelve 

 years Sir Richard Quain's comprehensive work has been the 

 standard dictionary of medical knowledge, and the practitioner, 

 teacher, and student alike have put their trust in it. The fact 

 that more than 33,000 copies of this work of reference have 

 been issued in this country and America suffices to show the 

 manner in which the labours of the editor and his eminent staff 

 are appreciated. To bring the book up to the present state of 

 knowledge was a laborious task, for, since the first edition was 

 published, the science and practice of medicine have made 

 enormous progress, and many new developments have occurred. 

 The work had, in fact, to be completely revise;!, and a large 

 number of new arlicles had to be prepared. The result of these 

 expansions is that the Dictionary now consists of two volume^, 

 entirely reprinted, while the number of pages have been increased 

 from 1834 to 2518. The editor, and his assistants, Drs. F. T. 

 Roberts and J. Mitchell Bruce, are to be congratulated upon 

 the accomplishment of their task. With the co-operation of 

 numerous members of the medical profession, they have launched 

 their treatise for a second time. We do not doubt that its 

 future career will be as successful as its past. 



Under the title "Proof Spirit and Fiscal Hydrometry," 

 Mr. John Hey wood has published a small book by Dr. B. 

 Derham. The author arraigns the legal definition of proof- 

 spirit, because it depends upon the indications of a certain 

 Sykes' hydrometer. This instrument, and the tables for use 

 with it, are shown to be open to objection. .Vccording to Dr. 

 Deiham, the proper allowances for variations of the temperature 

 of the hydrometer, and of the spirit stored in bonded ware- 

 houses, are not made. Accepting this, it is shown that the 

 Revenue suffers a considerable loss of duty on proof-spirits. In 



NO. I2S7, VOL. 50] 



fact, it is asserted that the Revenue estimate, for the yea, 

 1892-93, of the total quantity of proof-spirit, fell short of the 

 true estimate by 186,542 proof-gallons ; and that, consequently, 

 the loss sustained was ;ii^93,27l. .\nd, it may be added, since 

 the funds for technical education came from the wine and spirit 

 duties, Dr. Derham's book would seem to show that the moneys 

 available are less than they ought to be. Thus it appears that 

 the progress of technical instruction is dependent upon the 

 graduations of Sykes' hydrometer, a connection that reminds 

 us of Darwin's story of the relation between cats and clover. 

 Having pointed out the seeming defects in Sykes' system. Dr. 

 Derham develops a new system of hydrometry, and describes a 

 new form of hydrometer for carrying it into eflfect. His sug- 

 gestions may be worth the consideration of those responsible 

 for the proof standard. 



The hitherto unknown dimethyl arsine, (CHj^iAsH, has been 

 isolated by Dr. Palmer in the laboratory of the University of 

 Illinois, and is described by him in the current Berichte. It was 

 obtained by the reduction of cacodyl chloride. The most 

 advantageous mode of preparing it is as follows : — Granulated 

 zinc is first slightly platinised, then covered with absolute 

 alcohol, and sufficient hydrochloric acid added to produce a 

 rapid current of hydrogen. .-V mixture of cacodyl chloride, 

 hydrochloric acid, and alcohol is then allowed to fall into the 

 flask from a dropping funnel ; a reaction immediately com 

 mences, and copious vapours of the reduction product are 

 carried away by the escaping excess of hydrogen. The vapours 

 are conducted first through water contained in a couple of U- 

 tubes, then dried by passage through a calcium chloride tube, 

 and eventually led into a suitable receiver immersed in a freezing 

 mixture of ice and salt. The dimethyl arsine rapidly condenses 

 in the receiver to a colourless mobile liquid which boils at 36'. 

 It is endowed with the characteristic cacodylic odour, and 

 spontaneously inflames with some violence in contact with the 

 air. When air is admitted to the mixture of its vapour with 

 hydrogen a dense white cloud is produced, which rapidly settles 

 upon the walls of the vessel in the form of a crystalline deposit, 

 which is very soluble in water. Dimethyl arsine is completely 

 absorbed by silver nitrate from the mixture of its vapour with 

 hydrogen, with formation of a precipitate of metallic silver and 

 an acid substance which appears to be cacodylic acid. The re- 

 action which occurs in its preparation may be represented by 

 the equation : 



(CHjIjAsCI -1- H„ = (CH3).,AsH -^ HCl. 



If the cacodyl chloride is allowed to enter the reaction vessel 

 too rapidly, or if there is an insufficient supply of acid present, 

 the chief product of the reaction is cacodyl itself, (CH3)4.\=^ 

 Owing to the high boiling point of cacodyl, however, it is either 

 retained entirely in the reaction vessel or in the washing tubes, 

 so that the purity of the escaping dimethyl arsine is not 

 appreciably affected, although its amount is considerably 

 diminished. Dr. Palmer expects shortly to have a further 

 communication to make concerning the remaining unknown 

 organo-arsenic compound, raonomethyl arsine, CHjAsH;, 

 experiments being now in progress with a view to its isolation. 



The additions to the Zoological Society's Gardens during 

 the past week include a Black-headed Lemur (Lemur briiiiiieus, 

 S ) from Madagascar, presented by the Hon. Mrs. Fellowes ; 

 a Green Monkey (Cercopillitcits callitrichits, 9 ) from West 

 Africa, presented by Mrs. Flowers ; a Leonine Monkey 

 (AAicaciis leoiiinus, i ) from Burmah, presented by Mr. J. W. 

 Hunter ; a Brown Capuchin {Cibus fatiieltus, 9 ) from Guiana, 



presented by Mrs. J. L.Johnson ; a Mangabey (Cetcocebus, 



sp. inc. (5) from Ujiji, Lake Tanganyika, a Yellow Baboon 

 [Cynocephalus taboiiiii, 9 ), a Duyker-bok {Ccphalopliin mcr^cns. 



