PEE FACE. 



IN this second volume I have carried out the programme 

 which I put forward in the preface to the first volume, thus 

 finishing the first portion of my undertaking The History 

 of Scientific Thought in the Nineteenth Century. The 

 two volumes form a work complete in itself, and for this 

 reason I have attached an alphabetical index. 



In addition to the names I mentioned in the preface to 

 the first volume, I have to add those of other friends 

 who have been of great help to me in the course of 

 my work. With Professor Sampson, F.K.S., of Durham 

 University, I have had many helpful discussions on the 

 subjects of this volume, notably on chapters viii. and 

 xiii., which he read in proof. Mr Arthur Berry, M.A., 

 of King's College, Cambridge, has read over chapter 

 xiii., and made valuable suggestions. Mr Archibald S. 

 Percival, M.B., of Cambridge, has read over chapters 

 vi. and x. Professor F. G. Weiss, D.Sc., of Victoria 

 University, has read chapters viii. and ix. Mr Thomas 

 Whittaker has continued his revision, much to the benefit 

 of the book ; and Dr Spence Watson has given the finishing 



