July 15, 1909J 



NA TURE 



65 



volume. The subject is brought into touch with other 

 branches of the science. Thus, under hydrocarbons, 

 we read a little about thermochemistry ; under alde- 

 hvdes there is a reference to auto.\idation ; under acids 

 there are a few words about steric hindrance ; under 

 ethereal salts (a rather antiquated term) a short 

 account is given of mass action, and so forth. In 

 addition to this there are separate chapters on 

 laboratory methods, stereochemistry, the sugars, 

 dynamic isomerism, heterocyclic compounds, and the 

 physiological properties of organic compounds. 



That the subjects are treated rather broadly than 

 deeply seems no serious defect. They are sufficient 

 for the general reader, who is provided with elaborate 

 references if he desires to extend his knowledge. In 

 conclusion, we would direct the author's attention to 

 a few inaccuracies which have been noticed, and which 

 might be modified or corrected in a future reprint. 

 The two isomeric dimethylethylenes, which are stated 

 to be known in only one form, have been prepared bv 

 J. Wislicenus (p. 310); the molecular weight of 

 triphenylmethyl has been determined, and corresponds 

 to the double formula (p. 423) ; Fischer and Slimmer 

 were unsuccessful in effecting an asymmetric synthesis 

 (p. 301); it is incorrect to state that propylene and 

 hydrobromic acid give exclusively isopropvl bromide 



(P- 45)- 



We would also suggest the following : — Thiele's 

 hypothesis requires amplification to be understood 

 (p. 46); it is very questionable if the explosiveness of 

 a compound depends upon its breaking up into stable 

 molecules, for many silver salts share with silver 

 oxalate this property, whereas a substance like platinic 

 chloride does not explode ;. the statement that elhyl 

 and methyl " cannot exist in the free state because 

 they contain one of the carbon affinities unsaturated " 

 (p. 27) is inconclusive, especially as triphenylmethyl 

 is referred to later as possibly existing (pp. 36, 423) ; 

 without some qualification it is misleading to say 

 that Dumas's theory of types " was especially de- 

 veloped by Gerhardt," and "received the support of 

 Williamson and Wurtz " (p. 17). In the first place, 

 Williamson originated the idea of Gerhardt's types, 

 which were simple inorganic compounds in which 

 hydrogen could be replaced by radicals. They were 

 intended to denote chemical behaviour and not rela- 

 tionships. Ether had no generic relationship to acetic 

 anhydride, though they belonged to the same type. 

 Dumas's types, on the other hand, were organic sub- 

 stances which were intended to show relationships 

 produced by substitution rather than chemical 

 behaviour. 



(2) The " Practical Organic Chemistry " of Sud- 

 borough and James is rather a laboratory handbook 

 or book of reference than a course of practical instruc- 

 tion. As stated in the preface, examples are given of 

 different types of operations. These types are grouped 

 1 together. Thus, there is a chapter on the preparation 

 ' of hydrocarbons, one on alcohols, another on halogen 

 compounds, acids, esters, nitro-compounds, sulphonic 

 acids, and so forth. In addition, there is a pre- 

 liminary chapter on organic analysis and molecular- 

 weight determinations, and, at the end of the volume, 

 a number of useful examples of analyses and the 



NO. 2072, VOL. Si] 



determination of physical constants such as are play- 

 ing an increasingly important role in the study of 

 structure. The descriptions are clear and full, and 

 the photographic illustrations are masterpieces of their 

 kind. Altogether the book is probably the most com- 

 plete among those of home manufacture on the 

 subject of practical organic chemistry that has yet 

 appeared. 



(3) This modest little volume, which is one of the 

 University Tutorial Series, should form an excellent 

 introduction to the study of organic chemistry, and 

 if the process of practical instruction can be carried 

 on concurrently with theoretical teaching, as the 

 author does with his own class, nothing better could 

 be desired. He takes a few of the commonest organic 

 substances and uses them, as they can easily be used, 

 to illustrate quite a large variety of chemical opera- 

 tions and products. If the substance of the book can 

 be assimilated in the course of four school terms, as 

 the author states, we think that both teacher and 

 student should be satisfied with the result. May we 

 suggest that the name of \\'urtz should be spelt 

 without the diaeresis and Senderens without an a ? 



(4) One turns from the intricacies of a modern 

 treatise on organic chemistry to Wurtz 's classical 

 memoir on the glycols with the same sense of relief 

 that one listens to the simple melody of an early 

 composer after the confused sounds of a modern 

 orchestral symphony. Short and simple though it is, 

 it is difficult to overrate the far-reaching results of 

 Wurtz's research. It was not merely the discovery 

 of a new class of alcohols and organic o.xides, or an 

 extension of Williamson's water type. It afforded for 

 the first time clear experimental evidence of the exist- 

 ence of what were then termed " polyatomic " 

 radicals. To quote Wurtz's own words : — 



" The main result, which, in my opinion, is derived 

 from these synthetic experiments, is not the discovery 

 of the new compound, glycol — there are enough new 

 comjxiunds in organic chemistry — it is not even the 

 synthesis of glycerine nor the difficulties connected 

 with its preparation which have been successfully 

 overcome; but it is the manner of the formation of 

 glycol and the antecedent reactions which made it 

 possible ; it is the conversion of the allyl compound 

 by which the iodide passed into glycerine. All these 

 experiments, which were directed to the same end, 

 have shown that an organic group united to 2 atoms 

 of chlorine or bromine can replace two atoms of silver, 

 and are therefore equivalent to two atoms of hydrogen, 

 and that an organic group united to three atoms of 

 chlorine or bromine can replace three atoms of silver 

 and is equivalent to three atoms of hydrogen." 



The theory of polyatomic radicals, like ethylene and 

 glyceryl, soon developed into that of the polyatomic 

 elements or the theory of valency, upon which the 

 whole fabric of modern organic chemistry rests. 

 Wurtz himself held perfectly clear views on the dif- 

 ferent valency of the elements. In his address to the 

 Chemical Society in London in 1862 on ethylene oxide, 

 he points out that as ethylene oxide represents a 

 diatomic radical united to oxygen, so many of the 

 metals may be regarded as diatomic elements. The 

 paper is well worth re-reading, and is not by any 

 means the least interesting addition to the Klassiker. 



J. B. C. 



