To discuss in a single volume the progress of sci- 

 ence in the nineteenth century has been no easy task, 

 and the author craves the reader's indulgence. It 

 must be remembered that the book does not pretend 

 to be a history of nineteenth century science; it 

 is designed simply as an introduction to many histo- 

 ries some still unwritten. It is not a consecutive 

 story of the marvellous progress of knowledge which 

 the century witnessed ; it is simply a record of some 

 of the great scientific events. Many famous names 

 and many important discoveries have been left un- 

 mentioned, for any attempt at exhaustiveness would 

 have made a volume of this size a mere catalogue. On 

 the other hand, there has been a serious attempt to 

 discuss the great theme so as to give prominence to 

 the salient steps of progress. To have attempted this 

 in an easy-going mood would have been irreverent to 

 the past and insulting to the serious reader ; therefore 

 no apology is offered for the difficulty of some of the 

 pages, nor does it seem necessary to apologise for the 

 numerous quotations from expert authorities, they 

 help to give personal reality to some of the pages, 

 and they were needed as acknowledgments of the 

 author's indebtedness. J. A. T. 



USIVEBSITY OF ABERDEEN, SEPTESCBEB, 1902. 



Note. The reader will understand that the absence of any reference 

 to radium and its marvellous properties is due to the fact that the book 

 was printed before the discovery had been made. In the same way it 

 will be obvious why Sir Oliver Lodge and Sir William Kamsay are not 

 duly entitled, and why some great men of science no longer with us. 

 such as Gegenbaur, Spencer, and Zittel, are referred to in the present 

 tense. 



