6i8 



NATURE 



{Oct. 24, 1889 



1 846 ; the other an " elementary sketch," written after the 

 pubHcation of his volume of " Lectures on Quaternions." 

 He here again insists on the combination of the notions 

 of time and space in the quaternion. 



•' And how the One of Time, of Space the Three 

 Might in the Chain of Symbol girdled be." 



The appendix also contains Hamilton's account of 

 Madler's attempt to show that the Pleiades are the central 

 group of our sidereal system. The doctrine was un- 

 worthy of Hamilton's attention, and these pages are the 

 only ones in this volume which we would gladly have 

 seen omitted. Of infinitely more value are the remain- 

 ing pages, in which we find a carefully compiled catalogue 

 of all Hamilton's writings. There is also an interesting 

 list of the chief unpublished manuscripts of Hamilton 

 which have been preserved ; and finally, before the capital 

 index is reached, we have an enumeration, to which Prof. 

 Tait has contributed, of the chief works of other 

 mathematicians in which the quaternions have been 

 employed. 



It is impossible to read these volumes without acquiring 

 a feeling of admiration amounting almost to reverence for 

 the majestic intellect that they so adequately portray. In 

 his youth Hamilton set before himself with deliberate aim 

 the attainment of excellence in scientific work. Through- 

 out his life he spared no pains, he flinched from no labour^ 

 to attain his ideal. With wonderful singleness and con- 

 centration he devoted his life to work. His career affords 

 another illustration of the very close alliance if not actual 

 identity between genius and the capacity for taking pains. 

 If the quality of his work could not be surpassed, most 

 assuredly its quantity could hardly be rivalled, and yet 

 when we take leave of this work and ponder on the 

 lessons it teaches it is perhaps hardly on the intellectual 

 side of Hamilton's life that we shall find ourselves 

 meditating. It is impossible to follow that exquisite 

 correspondence between Hamilton and De Morgan with- 

 out thinking of the rare but well-deserved good fortune 

 which gave to De Morgan such a correspondent as 

 Hamilton, which gave to Hamilton such a correspondent 

 as De Morgan. On both sides these letters breathe a 

 lofty spirit of truthfulness and honour and of attachment 

 to whatsoever things are just and noble. Each shows a 

 charming conception of the respect due to his friend and 

 of the respect due to himself Friendship such as these 

 two men enjoyed was indeed a choice privilege. Hamilton 

 shows himself not only as the consummate mathematician 

 and philosopher, not only as the scholar and the poet, 

 but as the high-minded gentleman with whom exalted 

 conceptions of duty were habitual. 



Finally, we must express our obligations to Mr. Graves 

 for the admirable way in which he has completed his 

 monumental task. He was intrusted with the preparation 

 of the biography by Hamilton himself, and for laborious 

 years he has devoted himself to the charge which his 

 deceased friend laid upon him. Materials he had in 

 abundance the most prodigal. He has selected copiously 

 and he has selected judiciously, and he has told his 

 wonderful story with a literary gracefulness that we most 

 gratefully acknowledge. The memorable volumes of the 

 " Lectures on Quaternions " and the " Elements of Quater- 

 nions " have a place on the shelves of all scientific libraries 



which are worthy of the name. Beside them should be 

 ranged the three portly volumes in which Graves has 

 recounted the life of that astonishing genius by whom 

 Ouaternions were invented. 



THE ENGLISH TRANSLA TION OF 

 WETSMANN'S "ESSAYS." 



Essays on Heredity and Kindred Biological Problems. 

 By Dr. August Weisrnann. Authorized Translation, 

 Edited by E. B. Poulton, Selmar Schonland, and 

 Arthur E. Shipley. (Oxford: Clarendon Press, 1889.) 



THIS is the fourth volume of a very useful series of 

 translations of foreign biological memoirs, and the 

 Delegates of the Clarendon Press are again to be 

 congratulated on their choice of subject and editors. 



As the editors' preface tells us, since Mr. Shipley's 

 article, entitled " Death," in the Nineteenth Century for 

 May 1885, first called the attention of English biologists 

 to Prof. Weismann's essays, the interest in that author's 

 conclusions and arguments has become very general. This 

 interest has been stimulated and widened by the articles of 

 various authors in NATURE, by Prof. Lankester's addresses 

 at the Royal Institution, and, above all, by the great discus- 

 sion introduced by Prof. Lankester at the meeting of the 

 British Association in Manchester. No doubt a transla- 

 tion is superfluous, in these days of international science , 

 to most biologists. But this is much more than a tech- 

 nical treatise on a technical subject. It is of interest to 

 that far wider circle of readers and thinkers devoid of the 

 time or the opportunity to wrestle with the involved Ger- 

 man of the original. For to most the pith and kernel of 

 the whole book is the criticism, perhaps the refutation, 

 of the theory of the inheritance of acquired characters. 

 That theory is of immediate importance to biology, but 

 it is of equal, if remoter, importance to education and 

 morality. We are certain that biologists do not enjoy 

 a monopoly of education : we are by lio means certain 

 that they enjoy a monopoly of morality. 



The translation is very accurate and unusually elegant : 

 the foreign idiom has, to a large extent, been avoided, and 

 there is little trace of the intricacies of Teutonic inversion. 

 The footnotes are exceedingly useful, and many of them 

 introduce important collateral matter. For instance, on 

 p. 172, a concise and clear account is given of Mr. Francis 

 Galton's earlier and somewhat parallel explanation of 

 heredity. 



The typography is excellent, but the absence of spaced 

 type — a device of great utility in the original — is to be 

 regretted. 



The essays are translated in chronological order from _ 

 the revised German editions. And so, by a consecutive 

 perusal of the book, an historical conception of the wonder- 

 ful series of inductions and inferences may be gained. 

 Among the many converging lines of thought and work 

 that led to the conception of the germ-plasma as the basis 

 of heredity, two seem most clearly marked. In a pro 

 longed study of the Hydromedusss, Dr. Weisrnann dis- 

 covered that the generative cells were formed only in 

 certain localized areas. These special areas vary in 

 position in different species, and the differences in posi 

 tion correspond to the different stages in a process of 



