January 14, 1892] 



NATURE 



247 



towards the suppression of the insect pests of culti- j 

 vated plants. One effect of this welcome energy has j 

 been a process of differentiation, whereby the attacks i 

 of insects upon crops, instead of being included in 

 the comprehensive but somewhat incomprehensible 

 term of " blight," have been separated one from 

 another, more or less clearly defined, and, to a very 

 useful extent, associated respectively with the ravages of 

 certain specific insects. It is now possible for those to 

 whom the subject is new to obtain a much clearer idea of ! 

 the scope of agricultural entomology than was the case 

 even as recently as five or six years ago. " The time has 

 arrived," observes the author, " when, if we are to fight 

 insect pests successfully, united action must be taken, 

 and knowledge gained by constant vigilance, and by use- 

 ful and carefully conducted experiments. Only thus can 

 a better knowledge be obtained of the relations of insects 

 to agriculture, viticulture, and horticulture." 



About one-fifth of this volume of 150 pages is devoted ' 

 to an introduction to entomology, a classification of 

 insects, directions for collecting and preserving specimens 

 of economic interest, the preservation of insect-destroy- 

 ing birds, and certain horticultural quarantine rules. The 

 main part of the book is occupied with a discussion of four- 

 teen of the most troublesome insect pests of apples, pears, 

 apricots, and cherries in the colony of Victoria. These 

 are illustrated by means of coloured plates, the excellence 

 of which demands a word of approbation. The ever- 

 growing facilities for international transport are, no doubt, 

 partly responsible for the extent to which the insect pests 

 of this country are identical with those of the Antipodes. 

 In this connection it is worthy of note that at least five of 

 the pests which are illustrated have acquired as unenviable 

 a reputation in Britain as in Victoria. These are the 

 woolly Aphis (or American blight), the codlin moth, the 

 apple-bark scale, the red spider (an Arachnid), and the 

 pear and cherry slug, which is the slimy, repulsive-looking, 

 leaf-eating larva of one of the saw-flies. Of the fourteen 

 pests enumerated, the Lepidoptera claim four, Coleoptera 

 three, Homoptera two, Heteroptera two, Arachnoidea two, 

 and Hymenoptera one. 



The volume concludes with an instructive chapter upon 

 insecticides and the means for applying them. Amongst 

 the more noteworthy of the former are carbon bisulph- 

 ide, Gishurst compound, hellebore powder, kerosene 

 (petroleum), gas lime, London purple, Paris green, 

 sulphur, and tobacco. A caution is given as to the use 

 of certain so-called insecticides, such as ammonia and 

 carbolic acid. Insecticides they undoubtedly are, but 

 inasmuch as they injure the plant as well as kill its pests, 

 they had better be left alone. Various kinds of apparatus 

 for applying insecticides are described, and illustrated by 

 means of twenty wood-cuts. The most efificient and one 

 of the newest of these, the air-power distributor called 

 the Strawsonizer — after its inventor, Mr. G. F. Strawson, 

 an Englishman, — is adequately described and figured. 

 Several useful nozzles and pumps are likewise noticed. 



Mr. French has produced a volume of much practical 

 value, and it may be hoped that he will maintain the same 

 high standard in the subsequent parts. One appeal, how- 

 ever, may be made to the author — and not only to him 

 but to all writers upon this subject, — and that is to append 

 the name of the authority to the systematic name of each 

 NO. 1159, VOL. 45] 



insect. Agricultural entomology is necessarily a subject 

 of international interest, and much confusion arises — 

 especially in connection with American writings — through 

 an omission which might easily be remedied. The diffi- 

 culties of synonymy are great enough, without gratuitously 

 adding to them. 



OUR BOOK SHELF. 



Farm Crops. By John Wrightson, M.R.A.C, F.C.S. 



(London : Cassell and Company, Limited, 1891.) 

 The author introduces this volume of upwards of 200 

 pages as "an honest attempt to place the large sub- 

 ject of crop cultivation before the minds of children " ; 

 and this is, reasonably enough, his plea for its being 

 " penned in the plainest possible language." The work 

 belongs to " Cassell's Agricultural Readers," and the 

 several chapters deal with rotations of crops, the fallow, 

 root crops, corn crops, grass crops, grasses, clovers and 

 pasture plants, and the making and management of 

 pastures. 



Whether agriculture is a subject that can be at all 

 satisfactorily treated, in a book of the type which a 

 " reader" necessarily suggests, is a question that need not 

 be discussed here. But it is abundantly evident that the 

 problem has not been solved in the volume under notice. 

 It is sprinkled with footnotes and tables, the latter being 

 of as complicated a character as any which are usually 

 found in agricultural treatises. Then, again, there are 

 long quantitative lists of grass seeds recommended for 

 use in laying land down to pasture, and these, it is to be 

 feared, will be found both wearisome and unintelligible to 

 the small boy who has to wade through them in the course 

 of a "reading lesson." Indeed, the book is curiously 

 unequal throughout, and it is apparent that the author 

 would probably have done better had he not had to con- 

 tinually remind himself that he was writing a " reader "^ 

 for children. 



It is particularly desirable that, in a strictly elementary 

 book, everything should be correct ; but this is hardly the 

 case with some of the illustrations. In Fig. 2, for ex- 

 ample, the fruit of the cabbage is represented as dehiscing 

 from above downwards, though this is not the behaviour 

 of a siliqua in nature. On the other hand, the figures of 

 grasses are exceedingly good. 



The text is not free from errors. On p. 67 is described' 

 what will happen " if turnips braid {sic) too thickly."^ 

 The use of systematic names will rather hinder the 

 juvenile student than otherwise, unless special care is 

 taken to render them correctly, which is not always the 

 case. Occasionally, the fanciful element is in evidence,, 

 as when it is stated (p. 207) : " Mowing is as old as 

 Time itself; for has not Time been represented as carry- 

 ing a scythe over his shoulder ?" 



"In future editions," it is said in the preface, "this 

 little book may, no doubt, be further extended." It is 

 j questionable, however, whether the author would not 

 i more successfully meet the requirements of a " reader," 

 I of the kind which appears to be contemplated, by elimin- 

 ating all such matters as do not fall easily into the course 

 of a reading lesson. At present, it would seem as if the 

 object had been to produce a " text-book " rather than a 

 " reader." 



Arithmetic for Schools. By Charles Smith. " Pitt 

 Press Mathematical Series." (Cambridge : University 

 Press, 1891.) 

 Mr. Ch.^rles Smith is such a well-known writer of 

 mathematical Morks that we expected to find the present 

 volume very commendable. In this we are not dis- 

 appointed. The explanations of the fundamental principles- 



