CORRESPONDENCE, 1856-66. 311 



To Sir J. Herschel. 



91 Adelaide Road, N.W., May 30, 1862. 



MY DEAR SIR JOHN, I should not wonder if Sylvester and 1862. 

 you were at one without any intercommunication of your par- 

 ticles. I have had the same idea a long time. I have even 

 hinted at it through a glass darkly. In my third logic paper 

 there is the following passage : 'It is easy to frame hypotheses 

 which no one can of knowledge deny, under which attributes in 

 the brain should be as real as the sun in the heavens, or the 

 rocks on the earth, and this without a denying either the 

 existence of matter or the separate existence of mind.' If the 

 things of the universe be affections of the immovable primary 

 particles of space, the impresses on the brain may be veritable 

 copies, as real as the things themselves. A very pretty system 

 of pre-established harmony might be established. If all the 

 matter-universe be in motion of translation through the space- 

 nniverse or in transference, and if an individual in a certain part 

 of a certain nebula be to have a headache at a certain date, he 

 may at that date find the space particles, which are to keep up 

 his head, ready supplied with the adjunct affections confound 

 them, whatever they are ! which are essential to an ache of 

 predestined intensity. * How charming is divine philosophy ! ' 



Of course all this means that I have received your letter and 

 book. I will look at the latter, and let you have it back soon. 

 I never heard of the dialogue between Hermogenes and Her- 

 mione. The puzzle about oo arises much, I think, from a want 

 of distinction between the subjective and objective infinity. But 

 before I fairly tackle the subject I have to superintend and, en 

 Uoc, to calculate a valuation of about 30,000 life policies ; but 

 not 30,000 calculations Heaven in its mercy forbid ! But I 

 must leave off. With kind regards, 



Yours very truly, 



A. DE MORGAN. 



To Sir J. Herschel. 



91 Adelaide Road, Aug. 9, 1862. 



MY DEAR SIR JOHN, I return you with thanks your MSS. on 

 algebra. There are little bits here and there that I wish had 

 been published. Did it chance to you that the first thing you 



