6oo 



JVA TURE 



[October 17, 1901 



chapter dealing with the same projections in a sHghtly 

 more advanced manner, and concluding with a discussion 

 of projections of small areas. The popular description 

 is exceedingly lucid, and the style is everywhere clear. 

 The main defects of the book are that it is not sufficiently 

 systematic, its nomenclature is occasionally at fault, the 

 practical constructions in some cases are not the simplest, 

 and the drawing of the diagrams is somewhat careless, 

 so that statements in the te.'^t cannot always be verified 

 on the figures. For Lambert's equivalent azimuthal 

 projection, the author says there is no special name, and 

 he calls Lambert's equivalent cylindrical projection 

 simply the cylindrical projection. He omits Bonne's 

 projection and both the Sanson- Flamsteed and MoU- 

 weide (Babinet's), all of which should receive some notice 

 even in a popular work. 



He rightly insists on the value of gnomonic projections 

 for seamen, and of equivalent projections in our atlases ; 

 and desires the production of cheap and simplified globes. 



A. J. H. 



Smokeless Powder, Nitro-ccllulose and Theory of the 



Cellulose Molecule. By John B. Bernadou, Lieut. 



U.S.N. Pp. viii + 200. (New York : John Wiley and 



.Sons; London: Chapman and Hall, Ltd., 1901.) 



Price dollars 250. 

 This small work is of an entirely difterent character to 

 the usual text-books on explosives, the author confining 

 himself mainly to a theoretical consideration of his 

 subject. To all interested in the manufacture or use of 

 modern explosives the book should be of interest, throw- 

 ing as it does much light on the theory of nitro-cellulose 

 and mixtures containing this body, such as cordite or 

 powders containing metallic nitrates with nitro-cellulose. 



The book is divided into two parts, there being four 

 appendices occupying considerably over half the volume. 

 This latter portion is of most interest, for the author has 

 collected together translations of the admirable papers by 

 (i) Vieille, " Researches on the Nitration of Cotton " ; (2) 

 Mendeleef, " Pyrocollodion Smokeless Powder"; (3) 

 Bruley, "The Nitration of Cotton" (an extension of 

 Vieille's work). Appendix iv. consists of an abstract of a 

 lecture by the author on the development of smokeless 

 powder. 



In the early pages concise definitions and a list of 

 synonyms are given for the various substances dealt with, 

 which avoids much confusion. 



Some interesting work is recorded on the behaviour of 

 guncotton at low temperatures. With liquid air it was 

 found to be " not only not an explosive, but practically a 

 non-combustible ; while non-nitrated cotton under similar 

 conditions is a violent explosive." 



The remarkable action of very low temperatures in 

 effecting solution of nitro-celluloses is dealt with at some 

 length. McNab and others have shown that an insoluble 

 nitrocellulose becomes soluble in ether-alcohol at - 50', 

 and the author shows that these bodies are soluble in 

 ethyl ether under the influence of intense cold, and with 

 the exception of the highly nitrated insoluble variety, 

 they are soluble in absolute alcohol under similar 

 conditions. 



Lieut. Bernadou, in the latter part of the book, advances 

 an ingenious theory of progressive impulses in guns when 

 firing nitro-cellulose-nitro-glycerin charges, or colloided 

 nitro-cellulose with metallic nitrates incorporated. With 

 cordite, for example, "conditions point to there being 

 two intervals in the decomposition of the charge, during 

 one of which a maximum quantity of nitro-glycerin, and, 

 during another, a maximum quantity of nitro-cellulose is 

 burning." Finally, there may be a third impulse due to 

 combination of the gaseous products. This latter appears 

 to obtam confirmation from McNab and Kistori's analyses 

 of the products from the materials separately and cordite 

 {Proc. Roy. Soc, Ivi. p. 8.) 



NO. 1668, VOL. 64] 



In the space of a short review it is impossible to deal 

 in a satisfactory manner with the author's theory of the 

 cellulose molecule, many points being open to debate. The 

 author's formulae show four OH groups in the unit mole- 

 cule C|;H|„0^, which necessitates the assumption that on 

 nitration some of these groups are unattached, whereas 

 if the molecule is considered as having only three OH 

 groups the limit of nitration is easily accounted for. Again, 

 we are asked to assume that at low temperatures ethyl 

 alcohol " under strain " has the composition usually asso- 

 ciated with methyl ether, and that coUoidisation is brought 

 about by half molecules of ether or alcoh ol (under strain !) 

 combining with half molecules of the nitro-cellulose. 



J. S. S. B. 



Catalos:ue of the Collection of Birds' E^gs in the British 



Museum {Natural History). Vol! i. By E. W. 



Gates. Pp. xxiii-l-252. Illustrated. (London : Printed 



for the Trustees, 1901.) 

 Wf; have received from the Trustees a copy of this care- 

 fully compiled and beautifully illustrated volume, which 

 reflects the greatest credit on all concerned in its pro- 

 duction, and should prove invaluable to all ornithologists 

 and egg-collectors. As a matter of fact, it is somewhat 

 more than is indicated by its title, for the exquisitely 

 coloured plates illustrate the chief types of egg form and 

 coloration characteristic of the various groups of birds, 

 so that it forms to a great extent a manual of "oology." 

 We do not on the present occasion propose to review the 

 volume in detail, reserving this till the work is completed. 

 It may be mentioned, however, that the work is practi- 

 cally unique of its kind, the only other catalogue of eggs 

 published by the Museum having been issued so far 

 back as 1852, and treating only of British birds. 



The Trustees have been well advised in securing the 

 services of Mr. Gates, whose previous experience rendered 

 him peculiarly qualified to undertake this important task. 

 Of late years, owing largely to generous donors, the col- 

 lection of eggs in the .Museum has increased by " leaps and 

 bounds," and is probably quite unrivalled elsewhere. At 

 the present time it includes more than 50,000 specimens ; 

 but even this vast number, according to the author, repre- 

 sents only about one-third of the known species of birds. 

 An interesting feature of the volume is the account of the 

 growth of the collection, which forms a large part of the 

 introduction. 



With the bare statement that it includes the eggs of the 

 ostrich-like birds, the tinamus, game-birds, hemipodes, 

 sandgrouse, pigeons, rails, grebes, divers, penguins, 

 petrels, auks, and gulls, we take leave, for the present, of 

 a most valuable and instructive volume. R. L. 



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 cot respond with the writers of rejected 

 jianiiscripls intended for this or any other part of NatIJRE. 

 iVo notice is taken of anonymous communications.'^ 



The Colours of Guillemots' Eggs. 

 Your reviewer, in dealing with Mr. R. J. Ussher's work on 

 the birds of Ireland (see N.atl're, November 29, 1900, pp. loi 

 and 102), had his attention particularly drawn to two statements 

 concerning the eggs of the guillemot. In the first of these, 

 which occurs on p. 364 of his book, Mr. Ussher puts forward the 

 suggestion that ' ' the beautiful varieties of colouring must help each 

 bird to distinguish her egg from others lying near until they all 

 become stained and soiled " (the italics are mine). This is certainly 

 a very pretty hypothesis ; ijut is not the earlier part contradicted 

 by the part I have italicised ? It is certainly indirectly contra- 

 dicted by a statement on p. 365, where Mr. Ussher records 

 his belief that when the eggs of the guillemot are found, as they 

 sometimes are, in the nests of cormorants and kittiwaVes, " the 

 owners of the nest incubate the mixed clutches, and not the 



