58 THE LIFE OF JAMES D. FORBES. [CHAP. 



But whatever arguments Mr. Mackenzie may have 

 supplied him with, they seem to have had no weight 

 with Sir D. Brewster. The following extracts from 

 Brewster's letters to Forbes at this time are interesting, 

 in their bearing both on this subject and on other plans 

 of the young physicist : 



1 . . . I have been considerably puzzled how to advise, 

 you on the subject of the treatise on meteorology. Consi- 

 dering pecuniary motives as entirely out of the question, I 

 am disposed to dissuade you from your scheme. I wrote 

 a treatise on optics before I was your age, and the prin- 

 cipal novelty in it was to be the practical part. I 

 mentioned my scheme to Sir W. Herschel, with whom I 

 had then some correspondence. He advised me against 

 it, and I have since congratulated myself that I did not 

 print such a work. . . . 



* A first work clings to an author while he lives, and 

 hence it is of great consequence that it be an original 

 work worthy of the status in science which he is destined 

 to attain. 



' I would object less to a system of meteorology than to 

 an elementary treatise. ... I have no scruple in express- 

 ing my convictions that you are destined to do something 

 important in science, and under this conviction I am con- 

 fident that there is no object of ambition worthy of your 

 pursuit, but that of original discovery. 



' My conviction is that the very first thing a scientific 

 man regrets is that of writing a book at the beginning of 

 his career, however good it might be ; he sees how much 

 better it would have been had he waited a few years. 



' If you should view things in a different light, which 

 I dare say I would do in your circumstances, I shall be 

 most happy to forward your wishes, whatever they may be. 



' I would strongly advise you to continue your mathe- 

 matical studies, but to keep them in clue subservience to 

 your physical inquiries. ... If you should have any 

 spare time, you would oblige me much by a short notice 

 on Vesuvius, and touching very briefly on volcanoes ; but 

 if you have not time, do not think of it a second time. . . .' 



