PREFACE. 



When I had corrected the proofs of the concluding sheet of 

 the present volume, I considered that my labour was at an end ; 

 but I am told that there must be a Preface, and that I am gene- 

 rally expected to compose it of the memoirs of him whose loss I 

 have so much reason to deplore. 



This is a task, however, which I cannot undertake ; not because 

 it would add to the poignancy of my sufferings, for my greatest 

 happiness consists in talking or writing of him ; in retracing 

 every hour that we passed together, and in repeating aU I have 

 ever heard of him before we met. But my reason for dechning 

 it is, because his own numerous works are the best pictures of his 

 scientific labours and attainments ; and the only part of his 

 life which is not generally known, belongs to his domestic and 

 social virtues. On this subject I dare not trust myself to write, 

 as I might be led by affection and happy retrospect, to expatiate 

 in a manner that would be little interesting to the public. 



For the favourable reception of the first part of my book, I feel 

 little or no apprehension. The errors which may have crept 

 in when correcting the press, will justly be laid to my charge. 



