48o 



NA TURE 



[March 22, 1894 



attempt is very laudable. Knowing how often mosses 

 are foimd without fructification, he has endeavoured to 

 rely upon characteristics afforded by the barren plant, 

 and not upon those derived from the inflorescence or the 

 caosule. Whether so important a part of the structure 

 as the reproductive system can be safely neglected by 

 the systematist, seems to us at least doubtful. One has 

 heard the story of the man who boldly asserted that the 

 peristomes of the mosses were created different in order 

 to enable botanists to distinguish the species. That may 

 be rash teleology, and certainly Mr. Jameson has not 

 adopted it. 



As the book is intended for beginners, we think that 

 a glossary should have been given. 



E. F. 



OUR BOOK SHELF. 



Report of Observatio7is of Injurious Insects and Common 

 Farm Pests, during the Year 1893, with Methods of 

 Prevention and Remedy. By Eleanor A. Ormerod, 

 F.R.Met.Soc, &c. Seventeenth Report, ([.ondon: 

 Simpkin, Marshall, Hamilton, Kent and Co., Ltd.). 



Although the indefatigable Miss Ormerod, our prin- 

 cipal English agricultural entomologist, has lately 

 retired from the post which she has so long and so 

 worthily occupied in connection with the Royal Agri- 

 cultural Society, we are pleased to see that she has 

 by no means relaxed her exertions in the cause, but has 

 again brought out her usual annual volume, which will 

 bear comparison with any of those which have preceded 

 it, in the interest and value of its contents. 



The year 1893 was remarkable for the great drought, 

 which though it affected both vegetation and insect-life 

 less than might have been expected, was necessarily 

 favourable to the increase of some species, and injurious 

 to others. The most noticeable feature was undoubtedly 

 the unusual abundance of wasps over almost the whole 

 of Great Britain and the adjoining countries ; and thirty 

 pages of Miss Ormerod's report are devoted to wasps 

 alone. The remainder of this report treats of various 

 insects infesting apple, bean, corn and grass, gooseberry, 

 hop, mangold, mustard, pear, strawberry, tomato and 

 cucumber, turnip and willow ; and to the occurrence of 

 locusts and mites {Phytoptidcv), not attached to particular 

 plants. Most of the species noticed are freely illustrated 

 in their various stages, so that there ought to be no 

 difficulty about their identification, even by persons 

 ignorant of entomology. Particular attention is given, 

 as usual, to the best means of prevention and cure appli- 

 cable to each case. 



Fortunately the climate of England is less suited to 

 the excessive multiplication of many insect pests which 

 are highly destructive on the Continent and in America ; 

 and we are glad to notice that Miss Ormerod does not con- 

 sider that the Hessian Fly, about which so much anxiety 

 was felt a few years ago, is ever likely to become very 

 destructive with us. Miss Ormerod also prints a letter 

 from M. Schoyen, announcing the introduction of this 

 insect into Norway ; another instance of the impossi- 

 bility of preventing insect pests being carried by the 

 constant international traffic from country to country, 

 where they establish themselves if the climate and con- 

 ditions are favourable, but if not, they soon die out, or 

 linger on in too small numbers to be really injurious. 



The introduction of locusts into England in brocoli 

 from South Europe, and (dead) in large quantities 

 among hay from Buenos Ayres, is likewise worthy of 

 notice. 



Mustard beetles, and others of the more familiar farm 



NO. 1273, VOL. 49] 



and garden pests, still continue to require and to receive 

 a considerable amount of attention. 



In conclusion, we may express our hope that Miss 

 Ormerod may long be spared to issue many more of her 

 useful annual contributions to agricultural entomology. 



W. F K. 



On the Definitions of the Trigonometric Functions. By 

 A. Macfarlane. (Boston : J. S. Cushing and Co.) 



Dr. Macfarlane has already written on space- 

 analysis. The previous papers were on the principles of 

 the algebra of physics, I he imaginary of algebra, and 

 the fundamental theorems of analysis generalised for 

 space. The pamphlet before us was read before the 

 Mathematical Congress at Chicago, August 22, 1893. 



In the first of the above-cited papers the author 

 introduced a trigonometric notation. This has been 

 discussed by Mr. Heaviside in the Electrician (De- 

 cember 9, 1892). Dr. Macfarlane, by way of rejoinder, 

 remarks : " I believe that this paper will show that 

 trigonometry is not an application of space-analysis, but 

 an element of it ; and that the ideas of this element are 

 of the greatest importance in developing the higher 

 elements of the analysis." Our readers may remember 

 that the notation was also discussed by Prof. Alfred 

 i Lodge (Nature, November 3, 1892). To this our author 

 I replies : " I consider that the notation is a matter not of 

 secondary, but of paramount importance. If the nota- 

 I tion is arbitrary, it gives us no help in the further de- 

 I velopment of analysis; if on the other hand it is systematic 

 and logically connected with the existing notation of 

 analysis, it points the way to more general principles 

 and results. I believe that this paper will show that my 

 notation is systematic and logical." The pamphlet 

 occupies 49 pages, and there are some other passages 

 like tho-^e we have excerpted ; so there is likely to be a 

 pretty fight, of which our readers will soon hear more, if 

 they do not take part in the strife. The pamphlet will 

 repay perusal. 



Key to I^r. f. B. Lock's Shilling Arithmetic. By Henry 



Carr, B.A. (London: Macmillan and Co., 1894.) 

 In the worked-out results which we have now before us, 

 Mr. Carr has not restricted himself to giving the mere 

 answers, but has inserted in all cases the steps by which 

 they are reached. This, especially for beginners, will be 

 found of great service, and by judicious use will 

 certainly lighten the teacher's task. We have selected 

 many of the more advanced examples here and there, and 

 worked them out as a test of the accuracy of the results 

 given, and have found no mistakes. Others, per- 

 haps, may not be so fortunate, but all necessary care 

 seems to have been taken to give the right answers. All 

 who use Mr. Lock's shilling book will find it of great 

 assistance. 



LETTERS TO THE EDITOR. 



The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Natvrk. 

 No notice is taken of anonymous communications.^ 



The Thermal Expansion of Diamond. 



In view of the interest at present aroused by M. Moissan's 

 successful experiments upon the artificial production of diamond, 

 I venture to recount the results of some observations upon the 

 thermal expansion of diamond, which, I think, are suggestive 

 in connection wiih the particular manner in which M. Moissan 

 has achieved success. M. Moissan has shown that the added 

 condition of high pressure has rendered a method previously 

 unsuccessful now for the first time successful. 



Minute particulars being out of place here, I may briefly say 



i. 



i 



