286 MEMOIR OF DR. DALTON, AND 



Fourthly. I would add rapidity of conclusion. This may 

 arise in various ways. In a mind with weak conceptions or 

 pictures of things, rapidity may be great, but can be of no 

 value. In a tenacious mind like Dalton's, rapidity of concep- 

 tion is a combination of true ideas, so rapidly made that the 

 steps are not seen clearly by the mind itself, and hence that 

 inexplicable result which seems at least one of the ways in 

 which genius is produced. 



To understand the truth of these remarks the memoirs must 

 be read and compared with the times, for Dalton, although he 

 died but lately, flourished at the birth of true chemistry, and 

 his work was done when Berzelius was only commencing. 



By him laws were more easily treated than facts, and thought 

 was easier than observation. His mind was one of those which 

 especially sought laws, desiring to form the link between the 

 mental and material. He seldom observed without reasoning, 

 and he had no surplus observation : this made him of an absent 

 disposition. He seldom reasoned without observing : this 

 made him an experimenter. But in the movements of his mind, 

 as of his body, there was a certain rigidity, which he himself 

 seems to have felt, and for which others have endeavoured to 

 find causes. One quality Dalton had to a degree almost 

 unparalleled : the constancy with which he clung to his 

 occupation of observing and generalizing. 



His mind seems to stand before us as an intellectual tool, 

 constantly planing, drilling, and boring with never ceasing 

 activity, without any violent fits of haste, and without any 

 seasons of absolute rest. As far as I know I have indicated 

 what were the peculiar characteristics of that tool, but there is 

 no doubt that other circumstances might have brought into 

 activity a far difierent set of faculties. We see prominently 

 in him how one portion of the mind was willing to devote 

 itself to obscurity for the advancement of the others, how the 

 faculty which reasoned on the " Mind its ideas and affections," 



