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SCIENCE 



[N. S. Vol. XXIX. No. 755 



stack-room at any distance; farther apart or 

 nearer together, as required, irrespective of 

 their relation to daylight through the windows. 



5. As Mr. Green has pointed out, daylight 

 is injurious to books. 



6. The temperature of the room will be 

 more equable, the internal heat being retained 

 in the winter, and the external heat being ex- 



, eluded in the summer. 



I hope, if this commends itself to architects 

 and librarians, that some day the board of 

 'directors of a library may act upon it. The 

 •only drawback that occurs to me is that archi- 

 tecturally it would not be attractive in appear- 

 ance, but as the book-stack is usually in the 

 rear of the building and more or less hidden 

 from view, I think this would not be a very 

 serious objection. 



W. W. Keen 

 Philadeuhia, 

 April 30, 1909 



SCIENTIFIC BOOKS 

 The Thirteen Boohs of Euclid's Elements 

 Translated from the Text of Heiherg with 

 Introduction and Commentary. By T. L. 

 Heath, C.B., Sc.D. Cambridge, University 

 Press. 1908. Three vols. 

 Differential and Integral Calcidus. By 

 Daniel A. Murray, Ph. D., Professor of Ap- 

 plied Mathematics in McGill University. 

 New York, Longmans, Green and Co. 

 1908. Pp. xviii -1-491. 

 An Elementary Treatise on the Differential 

 Calculus Founded on the Method of Bates. 

 By William Woolsey Johnson, Professor 

 of Mathematics at the United States Naval 

 Academy, Annapolis, Maryland. New York, 

 John Wiley and Sons. 1908. Pp. x-fl91. 

 In these days of prolific writing when even 

 the worst books (if indeed such a lower limit 

 exists) must be " noticed " and the best, owing 

 to consequent lack of space, may not be really 

 reviewed, one is at a loss to know how prop- 

 erly to signalize the appearance of so impor- 

 tant and excellent a work as this latest 

 production from the pen of Dr. Heath. Of 

 this work it is safe to say — and that is much 

 — ^that no other better illustrates the great 

 service of British scholarship in rendering the 



ancient classics accessible and attractive to 

 our time, and no other better illustrates the 

 truth of Cousin's mot: La critique est la vie 

 de la science. No account of the work can be 

 bad if it has the effect of inducing the reader 

 to procure a copy for himself, and no account 

 can be good if it have the opposite effect. 

 For students and teachers of mathematics or 

 of philosophy, this edition of the " Elements " 

 may be said to be indispensable. 



It is only after examination of the volumes 

 that one can realize how utterly impossible it is 

 to convey in a few lines anything like an ade- 

 quate conception of the riches that Dr. Heath 

 has given us. Nevertheless, a few hints — the 

 meagerest of indications — must be given. 

 The introduction, which occupies more than a 

 third of the first volume, is composed of nine 

 chapters, entitled Euclid and the Traditions 

 About Him, Euclid's Other Works, Greek 

 Commentators other than Proclus, Proclus 

 and his Sources, The Text, The Scholia, 

 Euclid in Arabia, Principal Translations and 

 Editions, and (ninth chapter) On the Nature 

 of Elements, Elements Anterior to Euclid's, 

 First Principles, etc. Of the man Euclid, as 

 of many another great determinator of the 

 world's career, but little is known, and the 

 chapter on Traditions, though it furnishes 

 nothing new, is valuable as collecting, sifting 

 and citing the literature of the old. One of 

 the traditions, whether or not it be true in 

 fact, is at all events true in spirit, and will be 

 relished by that variety of practician engineer 

 who views mathematics as he views a wheel- 

 barrow or a spade. " But what shall I get by 

 learning these things?" said a pupil to Euclid 

 after learning the first theorem. Thereupon 

 Euclid called his slave and said, " Give him 

 threepence, since he must make gain out of 

 what he learns." The late Sylvestre, it is re- 

 membered, on being asked to state the " use " 

 of the theory of substitution groups, on which 

 he had been lecturing, replied, "I thank God 

 that, so far as I know, it hasn't any." It 

 would be interesting to know what proportion 

 of scientific men are aware of the fact that 

 Euclid wrote several scientific works other 

 than the "Elements," as the hopelessly lost 

 "Pseudaria," said by Proclus to be "by way 



