RENDU AND HIS EDITORS. 449 



" Of other criticisms, flattering and otherwise, I forbear to speak. 

 As regards some of them, indeed, it would be a reproach to that manli- 

 ness which I have sought to encourage in my pupil to return blow for 

 blow. If the reader be acquainted with them, this will let him know 

 how I regard them ; and if he be not acquainted with them, I would 

 recommend him to ignore them, and to form his own judgment of this 

 book. No fair-minded person who reads it will dream that I, in wait- 

 ing it, had a thought of acting otherwise than justly and generously 

 toward my predecessors, the last of whom,' to the grief of all who knew 

 him, has recently passed away." I thus show how willing I w^as three 

 weeks ago to let discussion cease. 



How a great and good man regarded this book is shown by the fol- 

 lowing extract from a letter from the late Prof. Sedgwick, to whom I 

 sent the first draft of the volume. I gather from the "Life and Let- 

 ters " that he was a friend of Principal Forbes. The extraordinary fresh- 

 ness of his nature breaks through the concluding lines, w^hich, save as 

 an illustration of this, I should hardly have ventured to quote. There 

 are pthers which I omit for obvious reasons : 



" Cambeidge, January 29, 1S73. 



" My deae Peofessoe : T write to thank you for the little book upon the gla- 

 ciers of the Alps you had the kindness to send to me, and for the instruction and 

 delight its perusal gave me. ... It shows a power of putting the subject in the 

 clear, bright colors of daylight before the reader's eyes, and making him feel 

 as if he were your happy companion and fellow-laborer. 



"Truly and gratefully yours, A. Sedgwick." 



This is the language of a philosopher who took my words as they 

 stand, and did not think it necessary "to put that and that together," 

 so as to convert my statements into " straightforward English." 



The law of causality is now an a priori dictum of the human mind. 

 There is no spontaneous generation of phenomena ; and, like all other 

 things, the book now under consideration had its antecedents. These 

 are in great part to be found in a discussion which occurred twelve 

 years ago regarding the scientific position of a noble but a sufiering 

 man. By his unaided genius. Dr. Robert Julius Mayer, of Heilbronn 

 in Germany, reached the heart of a generalization, which the profes- 

 sional hierarchy of science in his day had failed to reach, and which in 

 its later developments ranks as high as the principle of gravitation. 

 For this great Bahnbrecher I sought recognition ; but the recognition 

 was by no means immediate, nor was my act applauded by all. Much 

 the reverse. I was accused, not only of want of patriotism, but of 

 " depreciation and suppression." I was charged w4th ignorance, and 

 an " abuse of language." Every spark of originality was denied to Dr. 

 Mayer. The calculation of the mechanical equivalent of heat, which I 

 had ascribed to him, was claimed for M. Seguin, who, it was alleged, 

 had, three years before Mayer, made the same calculation, and obtained 



^ Agassiz. 

 YOL. v.— 29 



