160 MEMOIR OF AUGUSTUS DE MORGAN. 



84 ?- wanted the interference of a Mathematician very much.' 

 conTro- n He asked Dr. Logan to tell him of any place in which the 

 versy. history of the syllogism is given anything about Barbara, 

 Celarent, &c., their birth, parentage, and education. He 

 also gave him some of the results of his recent inquiry 

 into the application of the Theory of Probabilities to ques- 

 tions of argument and authority. In reply to this, Dr. 

 Logan sent him a short note on the history of Logic. 

 On September 30 he wrote to Sir William Hamilton, the 

 Professor of Logic in the University of Edinburgh, 

 ' inquiring about the history of the Aristotelian theory 

 of the syllogism.' l This was answered in a friendly 

 tone, Sir William Hamilton sending Mr. De Morgan 

 f a copy of the requisites for a prize essay,' given out to 

 the students at the close of last session, and offering 

 further information if required. But in all the state- 

 ments of what had been taught by the Edinburgh Pro- 

 fessor my husband did not find any reason for believing 

 that his own discoveries on the syllogism had been antici- 

 pated; and he was able to bring forward distinct proof 

 that, even on the quantification of the predicate, which 

 had been taught in a form less complete than his own 

 by Sir William Hamilton, he had himself never had the 

 opportunity of gaining a suggestion from the Edinburgh 

 lectures. However, after the Cambridge tract had been 

 in Dr. WhewelFs hands, and in answer to a letter on the 

 subject from Mr. De Morgan, Sir William says that he 

 (Mr. De Morgan) is wholly indebted to himself for infor- 

 mation on the subject; and in his own words, 'should 

 you, though recognising always my prior claim, give forth 

 that doctrine as a speculation of your own, you will be 

 guilty pardon the plain speaking both of an injurious 

 breach of confidence towards me and of false dealing 

 towards the public.' 



To this the following reply was sent : 



1 I have always used, as far as possible, Sir William's own words 

 from his subsequent letters on the transaction. S. E. De M. 



