33^ 



NATURE ^"O 



\_Aiigust 7, 1879 



that they hare a great dislike to violet light however 

 obscure, and a preference for dark green and red ; but 

 we can hardly tell whether this effect depends on any 

 visual perception, or on a general sense of discomfort in 

 the one case and pleasure in the other analogous to the 

 effects of heat and cold upon ourselves. 



The last two lectures give a clear and condensed 

 summary of the present state of our knowledge as to 

 prehistoric man, and are well worthy of study by those 

 who may be inclined to doubt the value of the conclusions 

 arrived at by the new science of Prehistoric Archajology. 

 There is here of course nothing but what is well known 

 to all who have paid attention to the subject. It is, 

 however, interesting to note how sharp and striking the 

 contrast between the Palaeolithic and Neolithic ages 

 appears, when their characteristic features are briefly 

 summed up side by side as we here find them. Whether 

 we consider the tools, weapons, and other works of art, 

 the character of the contemporary animals, the physical 

 geography of the country, or the distribution of man 

 himself, we cannot but be impressed with the profound 

 chasm, which in Europe at least, separated the Pakeolithic 

 from the Neolithic man. And as, since the glacial epoch 

 passed away we have no evidence of any physical changes 

 calculated to produce such a chasm, it seems natural to 

 suppose that it was the result of the cold period itself, and 

 that, as many geologists now maintain. Paleolithic man 

 lived before the glacial epoch and during interglacial 

 mild periods, while Neolithic man made his first appear- 

 ance only when the ice-age had finally passed away. On 

 any other theory we have no adequate cause adduced for 

 a discontinuity so vast in its proportions and extending 

 over so wide an area. A. R. W. 



OUR BOOK SHELF 

 Dairy Farmirtg; or, The Theory, Practice, and Methods of 

 Dairying. By J. P. Sheldon, assisted by leading au- 

 thorities in various countries. Part I. (London : 

 Cassell, Petter, and Galpin, 1879.) 



The prospectus of this work promises us a thorough 

 treatment of all parts of the important subject of dairy 

 farming. The selection, breeding, and feeding of dairy 

 cows ; the production, treatment, and disposal of butter 

 and cheese ; the plants or crops used in feeding animals ; 

 dairy buildings, and soils adapted for dairy farms ; such 

 are some of the subjects embraced in the scheme of Mr. 

 Sheldon's serial work, the publication of which, in 

 monthly parts, has recently commenced. The first num- 

 ber, being chiefly occupied with general introductory 

 remarks, hardly affords a fair sample of what the bulk 

 of the book is likely to be. These prefatory pages do, 

 however, contain a good deal of interesting matter — matter 

 important to many persons besides dairy farmers. Some of 

 the statistics of milk- and cheese-production here given 

 are very striking. For instance, we are told (p. 9) that 

 about 500,000 tons of ripe cheese could be made from 

 the milk annually produced in the United Kingdom, ^ 

 when the quantity of milk required for rearing and fat- 

 tening calves has been deducted. But, in point of fact, 

 much milk is consumed as such in food, while from that 

 which is submitted to further dairy operations a good 

 deal of butter is made. The approximate estimates, 

 therefore, for the amounts of milk and milk-products in 

 question will stand somewhat as follows for the United 

 Kingdom : — Milk annually consumed as such, 525,000,000 

 gallons; 126,000 tons ripe cheese from 350,000,000 gal- 

 lons; 89,29s tons of butter from 550,000,000 gallons. 



When the cheese, butter, and condensed milk imported 

 from abroad are added to the home production, some 

 notion of the vastness of the amount of dairy products 

 consumed by the population of the British Isles may be 

 gained. Thus, 98,000 tons of cheese are annually brought 

 into this country from the Continent, the United States, 

 and Canada ; while the yearly import of butter ap- 

 proaches 90,000 tons. The value of our imports of 

 butter and cheese together is just 15,000,000/. sterling. 



It seems somewhat ungracious to say one word in dis- 

 paragement of any part of an undertaking which pro- 

 mises so well as does Mr. Sheldon's "Dairy Farming." 

 But we feel bound to hint that more care should be taken 

 in securing the accuracy of any physiological and chemi- 

 cal explanations that it may be thought expedient to 

 introduce into the volume. The figures and statements 

 on pp. vi. and vii. of the " Introduction " require revision. 

 We give an instance. We are told (p. vi.) that i lb. of 

 milk contains '65 ounce of flesh-formers and I'ji ounce 

 of heat-givers. Now the latter figure has been reached 

 by adding together the fat and sugar of the milk without 

 the previous conversion of the former into its starch- 

 equivalent. It is needless after this to say how idle are 

 all the subsequent comparisons of milk with other foods, 

 vegetable and animal. 



Marcus Ward's Arithmetic. J. W. Marshall, M.A., 

 Assistant-Master at Charterhouse School. (London : 

 Ward and Co., 1879. 232 pp.) 



This is a neatly got up arithmetic; it contains a great 

 number of exercises, covering the usual ground occupied 

 by such treatises, has a modicum of explanatory matter, 

 and calls for no further comment. There are no answers 

 at the end, but they can be got in a separate form. 



A Collection of Problems on Plane Geometrical Draw- 

 ing, including Problems on a few of the Higher 

 Plane Curves, &c. By E. F. Mondy, A.R.S.M, 

 2 vols. Text and Plates. (Tokei. 127 and ix. pp.) 



A COLLECTION of problems arranged for the use of the 

 students in the Imperial College of Engineering, by the 

 First Whitworth Scholar (1871), and Professor of Drawing 

 in the College. The author's aim has been to arrange the 

 earlier problems so as to render it of service to students 

 to work these while reading Wilson's Geometry, the 

 text-book used in the Mathematical Class. The treat- 

 ment is mainly founded upon the recognised English 

 text-books, but a novel feature, perhaps, is the extent of 

 space devoted to the conic sections and the higher plane 

 curves, "especially as regards the use of equations to 

 these curves and to the various geometrical elements con- 

 nected with them." 



Thus constructions are given for the tangents and radii 

 of curvature, and problems in areas are worked out. 



The book is, under the circumstances, very fairly got 

 up as regards the printers' work, and the matter is de- 

 serving of commendation for its arrangement. 



< .ur own experience of Japanese students is that they 

 take very kindly to this branch of mathematical instruc- 

 tion, and the productions of some we could name rank 

 among the neatest we have seen. The plates are in a 

 separate work from the text, a convenience in some 

 respects for the student. 



'/Essai sur les Principes fondatnentaux de la Giom'eirie et 

 de la Mdcanigue. Par M. de Tilly. (Paris : 1878. 

 190 pp.) 



This valuable treatise forms the first cahier of the third 

 volume of the Mhnoires de la Societe des Sciences 

 physiques ct naturelles de Bordeaux, 2' s6ne. The first 

 chapter— General Geometry— discusses the elementary 

 notions and axioms of the subject in a way that will 

 satisfy an anti-Euchdian, but we fear the nerves of 

 Euclidian adherents would suffer a shock at the bare- 



