i02 



NA TURE 



[Jwic II, 1874 



guished French savan has never had any hold, it may 

 seem superfluous now-a-days to take up time in the dis- 

 proof of it. But those who know what a power Elie de 

 Beaumont has been and still is in France, how with all his 

 abilities and knowledge and the excellent service which 

 he has rendered by his map and other publications, he 

 has for many years been a kind of dark shadow on the 

 progress of the newer geology in his country, will thank 

 the Professor at Poitiers for taking such pains to demo- 

 lish the riseati pentagonal. 



OUR BOOK SHELF 

 Handbook of Natural Philosophy. Bv Dionysius Lardner, 

 formerly Professor of Natural Philosophy and Astro- 

 nomy in University College, London. " Hydrostatics 

 and Pneumatics." New Edition, edited, and the greater 

 part rewritten by Benjamin Locwy, F.R..-\.S. (London : 

 Lockwood and Co., 1874.) 

 Dr. L.\RDNEr'S treatise on Natural Philosophy is quite 

 familiar to those who studied Science ten or fifteen years 

 ago. Before Ganot and Privat-Deschanel were translated, 

 Lardner was the book which everyone used. It was ori 

 ginally almost a translation of Pouillet's " Elements de 

 Physique," but was added to from time to time, and is 

 still a valuable text-book, especially the new editions of it 

 edited by Prof. G. C. Foster, and (as in the present in- 

 stance) by Mr. Benjamin Loewy. The value of the book 

 is indeed shown by the fact, that although first published 

 many years ago, it is still deemed worthy of new editions, 

 and of being edited by well-known men. The volume 

 before us has been carefully edited, augmented to nearly 

 twice the bulk of the former edition, and all the most 

 recent matter has been added. The treatment is essen- 

 tially experimental and elementary ; a slight knowledge 

 of mathematics is needful. It is to be regretted that Mr. 

 Loewy has not introduced metrical weights and measures. 

 A few omissions may be noticed : the lutioii latcralc of 

 Venturi is scarcely alluded to ; the theory of the trompe 

 is omitted, as are also the hydrodynamic experiments of 

 Plateau and JNIagnus, and the account of Dr. Guthrie's 

 experiments on approach caused by vibration. But the 

 book has in the main been carefully edited and improved. 

 Lcs explorations Sous-Marines. Par Jules Girard. 

 (Paris : Libraire, F. Savy, 1S74. London : Dulau and 

 Co.) 

 No nation surpasses the French in brilliant popular ex- 

 positions of the various departments of Science. They 

 already possess a large number of works of this kind, 

 several of which have been translated into English, and the 

 present work by M. Girard deserves to take its place among 

 them as an extremely interesting and wonderfully fullaccount 

 of the numerous and valuable results which have of late 

 years been obtained by deep-sea exploration. The two 

 introductory chapters gives a rapid resume of the history 

 of deep-sea exploration, with a short description of the 

 interior economy of the Challe/ti^er, and a clear and pretty 

 full description of the various apparatus used in carrying 

 on the explorations. The subsequent part of the work 

 consists of four divisions, the first of which treats of the 

 characteristics of the sea-bottom looked at in its geo- 

 graphical relations ; the second treats of life in the depths 

 of the sea, describing eloquently the various organisms 

 which inhabit the ocean ; the third division deals with 

 the waters themselves, pointing out the chemical proper- 

 ties and the physical phenomena which take place in the 

 midst of the ocean^; m the last division an attempt is 

 made to depict the seas of ancient geological epochs, and 

 compare them with the discoveries which have been 

 made by recent soundings. The author seems to have 

 fairly mastered the literature of his subject, and has 

 managed to write a book containing a vast deal of infor- 



mation conveyed in clear and eloquent language. The 

 work is profusely illustrated with artistically executed, use- 

 ful, and most attractive woodcuts. The work might well 

 be translated into English. 



LETTERS TO THE EDITOR 



[Tlie Editor does not hold himself responsible far opinions expressed 

 by his eorrespondents. No notice is taken of anonymous 

 cornniunications .] 



The Habits of various Insects 



[The following letter on this subject, from Fritz Muller to 

 Mr. Charles Darwin, F.R.S., has been forwarded to us for 

 publication by the latter. — Ed.] 



I DELAYED answering your kind letter of January I till I 

 should have had an opportunity of examining once more some 

 nests of leaf-cutting ants, to which you had directed my attention. 

 In tlie meantime I received Bell's '* Nicaragua," wliich I have read 

 with extraordinary interest, and for which I must express to you 

 my hearty thanks. 



I was much surprised to learn from Mr. Belt's book how 

 closely the far-distant province of Chontales resembles by its 

 vegetation and animal life our own of .Sta. Catharin.i. I am 

 thus enabled fully to appreciate the exactness of many of his 

 statements ; he is an excellent observer, and most of his theories 

 are very seducing. As to leaf-cutting ants, I have always held 

 tlie same view which is proposed by Mr. Belt, viz. that they 

 feed upon the fungus growing on the leaves they carry into 

 their nests, though I had not yet examined their stomachs. Now 

 I find that the contents of the stomach are colourless, showing 

 under the microscope some minute globules, probably the spores 

 of the hmgus. I could find no trace of vegetable tissue which 

 might have been derived from the leaves they gather ; and this, 

 I tliink, confirms Mr. Bell's hypothesis. Here, as in Nicaragua, 

 the Cecropia' are always mhabited by ants, but, I think, by only 

 a single species. I have cut down hundreds of them and never 

 missed the ants. I wonder that it had never occurred to me 

 that the trees are protected by the ants ; but there can be no 

 doubt that this is really the case, for young plants of Cecropifc, 

 not yet inhabited by ants, ."re uften attacked by herbivorous 

 insects. 



A few days ago I caught on the flower of a Vernonia a female 

 moth belonging to the Glaucopidas, of which family there are 

 here numerous species. When I seized it by the wings nearly 

 the whole body became suddenly enveloped in a large cloud of 

 snuw-white wool, which came out of a sort of pouch on the 

 ventral side of the abdomen, and consisted of very thin flexuous 

 hairs I — 2 mm. long, three, four, or five of which used to proceed 

 from the same point. I preserved the moth alive for some time, 

 and as often as I seized her by the wing.s, by inflating the abdo- 

 men, a large naked membrane became visible, and somewhat 

 protruded behind the first (white) segment of the ventral face of 

 the abdomen (the rest of which is black), and a little more wool 

 appeared under the posterior margin of this segment. I am at 

 a loss as to the meaning of this curious contrivance. There is in 

 the males of the same family an interesting secondary sexual 

 character ; they are able to protrude from near the end of the 

 abdomen a pair of long hollow hairy retractile filaments, which 

 in some species exceed the whole body in length. In the beau- 

 tiful Bcleinnia inauraia there is a second pair of shorter fila- 

 ments which are wanting in all the other species I examined 

 {Eunomiii ea:j;rus, Eueltrotnia jncunda, Agyrta ceernlca, Eudule 

 invaria, Leiicopsuniis sp., Philoros sp., &c., the names of which 

 I owe t ) the kindness of Dr. A. Gerstacker, of Berlin). In 

 some species, most distinctly in Bilemnia inaurati, I perceived 

 a peculiar odour when the filaments were protruded ; this, I 

 think, may serve to allure the females, which in all our species 

 appear to be much less numerous than the males. 



I mentioned to you that with our stingless honey-hees wax is 

 secreted on the dorsal side of the abdomen ; now this is also the 

 case with some of our solitary bees, for instance, A nthophora 

 fidvifrons Sm., and with some species nearly allied to that genus. 

 These solitary bees probably use the wax only to cement 

 the materials with which they build their nests. Our species of 

 Melipona and Trigona also never employ pure wax in the con- 

 struction of their cells or of the large pots wherein they guard 

 their provisions ; they mix it with clay, resinous substances, &c. , 

 so that in some species wax forms hardly to per cent, of the ma- 

 terial. The only case, as far as I know, in which pure wax is 



