112 MEMOIR OF AUGUSTUS DE MORGAN. 



1841. The early history of algebra is a very interesting subject, 



and I shall be glad to return to it again with more leisure. I 

 was forced to copy writers of credit, not always seeing the full 

 force of what they said. But it seemed to me that a sound 

 mathematician would find that field not exhausted. . . . 



As to your observation about logic that is, the syllogistic 

 logic perhaps I was a little influenced by the impression that 

 more attention was paid to it at Oxford. That, I believe, is now 

 much less the case. But though what I have written on it is 

 inconveniently concise, and leaves more for the reader than an 

 ordinary author has a right to expect, I thought I had given to 

 that logic what it can best claim, its quality of perfect demon- 

 stration ; all geometrical demonstration being, in fact, one species, 

 or rather one application, of the fundamental principle. Nor 

 did I distrust the usefulness, to a certain degree, of an acquaint- 

 ance with syllogism, though I have not found that the best 

 reasoners are very familiar with it. However, if I have gone 

 too far in lowering this art or science for it is not settled which 

 I am very willing to retract. Let me add that I have received 

 much pleasure from some of your writings, such as are most 

 familiar to me, especially that on the ' Connection of Number 

 and Magnitude.' You need not fear going ultra crepidam, for 

 your crepida is very extensive. 



Believe me, dear sir, 



Tour much obliged servant, 



HENEY HALLAM. 



In October oar second son, George Campbell, was 

 born. We lost him at the age of twenty- six, not before 

 his mathematical talents were developed sufficiently to 

 entitle him to notice in his father's scientific history. Of 

 this I must speak later. He was a lovely and seemingly 

 healthy child, sweet-tempered, quiet, and thoughtful ; and 

 though sound and certain in all, he was not quite so 

 quick in learning as his sister and brother. 



Our society was diminished by the loss of Mr. Sheep- 

 shanks, who left London to live at Reading with his 

 sister. 



The correspondence with Dr. Whewell, which had 

 begun soon after the pupil left Cambridge, related at first 



