January 2, 19 13] 



NATURE 



489 



stantly exhibited by his subjects, but we confess 

 that our faith in these attributes is of the weakest. 

 The female Lycosid may carry her own young', but 

 she will also carry any other young family indis- 

 criminately, and the author refrains from telling- 

 us that Atypus afjinis will devour her own brood 

 should they unduly delay their departure from 

 the parental abode. The elaborate nest once 

 begun by Agelena will be carefully completed 

 and guarded, whether the egg's are removed or 

 not. Mr. Ellis tells us that his book is primarily 

 intended for young folk, but it will undoubtedly 

 be of interest both to the naturalist and the 

 general reader. 



(3) In this work the authors have provided a 

 text-book for beginners undertaking a course of 

 elementary entomology. The book is divided into 

 three sections, the structure and growth of in- 

 sects, descriptions of species typical of the orders, 

 and a section containing a series of laboratory 

 exercises, together with a key to the orders and 

 information concerning the apparatus and methods 

 employed in collecting and preserving. We have 

 rarelv seen a work in which so large an amount 

 of information is compressed into so small a space, 

 and the text is well and profusely illustrated. 

 Such errors as we have found are but few, and 

 detract little from the general usefulness of the 

 work. The statement that the mouth ' parts of 

 Lepidoptera are so formed as to preclude injury 

 to vegetation is scarcely correct, since at least 

 two African Noctuids do no small damage to 

 peaches by piercing the skin and sucking the 

 juices, whilst the Australian Ophideres fullonica 

 attacks oranges, and, as pointed out by Francis 

 Darwin many years ago, has the proboscis 

 specially modified in adaptation to its habits. 

 The statement that all moths are night flyers 

 seems to require some modification. 



So long as there is no universally accepted 

 classification of the Insecta we must refrain from 

 too great comment on this portion of the work, 

 though we think it would have been better to 

 point out the sexual differences in the tarsi of 

 the Nymphalidaj and Lycanidse, and the 

 Erycinidse should find a place in even a con- 

 densed table. Compared with the general utility 

 of the work these are, however, but small matters, 

 and will doubtless be amended in a second edition, 

 which we fully expect will soon he required. 



(4) The author of this work has drawn upon 

 his wide and lengthy experience of collecting to 

 provide an extremely pleasant and readable 

 account of a selection of European Lepidoptera. 

 We confess to a feeling of satisfaction that the 

 work tends to lead the young lepidopterist away 

 from the narrow insularity so long and painfully 

 associated with the old-fashioned British collector. 

 The inflated value often placed on British examples 

 of species which may be pests on the Continent 

 is essentially unscientific. For the collector who 

 can extend his field to the Continent Mr. Rowland- 

 Brown's work provides just the information which 

 will awaken and maintain a healthy interest in 

 the subject. 



XO. 2253, VOL. 90] 



In criticising- the coloured plates one must bear 

 in mind the low cost of the volume, and if the 

 figures are not always typical of the best in 

 lithographic art they are at least free from that 

 crudeness of execution which is not always absent 

 from many more costly productions. Whilst we 

 find no fault with the work itself we trust the 

 author's well-known talents, both as a writer and 

 a naturalist, will soon find expression in a volume 

 of a more advanced type. 



NATURAL AND SYNTHETIC RUBBER. 



UNDER the above title an interesting address 

 was delivered by Dr. F. Mollwo Perkin 

 before the Society of Arts on December ii. After 

 briefly reviewing the history of the development 

 of the indiarubber industry and the nature of the 

 processes used in extracting the natural product 

 and in vulcanisation, an account was given of the 

 recent synthetic processes by which the manufac- 

 ture of artificial rubber on the large scale has 

 become a commercial possibility. In the process 

 of the Synthetic Products Co. isoprene is made 

 from fusel oil, which is fractionated so as to give 

 isoamyl alcohol, CH(CH3).-CH,-CH,-OH, which is 

 converted into the chloride, CH(CH3).2-CH2-CH2-C1 

 by the action of hydrochloric acid and then into 

 the dichloride C(CH3)2C1-CH3-CH,-C1 by the 

 action of chlorine, under specially controlled con- 

 ditions ; the dichloride obtained is passed through 

 a tube heated at 470° and filled with soda-lime, 

 whereby it is converted into isoprene, which can 

 be polymerised to rubber by means of small quan- 

 tities of sodium. 



The only difficulty in the way of this process is 

 the cost of the raw product, amyl alcohol, which 

 is about 140/. per ton. On this account, Prof. W. 

 H. Perkin, with E. H. Strange, F. E. Matthews, 

 and Prof. Fernbach, devised a process for obtaining 

 butyl alcohol cheaply, from which butadiene could 

 be obtained. By the employment of a certain 

 organism, it was found possible to ferment starch, 

 and, more recently, sawdust, so as to obtain butyl 

 alcohol and acetone, the latter being sold, thus 

 cheapening the cost of the butyl alcohol. The 

 butyl alcohol is chlorinated in the same way as 

 the ixoamyl alcohol, and by similar treatment with 

 soda lime yields butadiene, CHo;CH*CH!CH2, 

 which on polymerisation gives a rubber which, 

 although not chemically identical with the poly- 

 merised isoprene, has all the properties of natural 

 rubber in regard to elasticity and behaviour 

 towards sulphur on vulcanisation. 



An account was also given in the lecture of the 

 processes devised by the firm of Friedrich Bayer, 

 of Elberfeld, and of the interesting fact discovered 

 by Prof. Harries that the presence of a small quan- 

 tity of rubber ozonide very much increases the 

 rapidity of polymerisation of isoprene and its 

 derivatives. 



In discussing the question of the competition of 

 natural and synthetic rubber, it is pointed out that 

 " at present prices and with the present supply and 

 demrmd there is no reason, provided synthetic 



