380 JAMES CLERK MAXWELL. [CHAP. XII. 



I think it is a great improvement on the Quarto, both in 

 size and quality. It is the size of this paper I write on. 



I have not asked you if you wish to go to sermon on 

 Colour, for I do not think the R I. 1 a good place to go to 

 of nights, even for strong men. I have, however, some tickets 

 to spare. 



The peculiarity of our space is that of its three dimen- 

 sions none is before or after another. As is x, so is y 

 and so is z. 



If you have 4 dimensions this becomes a puzzle, for 

 first, if three of them are in our space, then which three ? 

 Also, if we lived in space of m dimensions, but were only 

 capable of thinking n of them, then 1st, Which nt 2d, If 

 so, things would happen requiring the rest to explain them, 

 and so we should either be stultified or made wiser. 



I am quite sure that the kind of continuity which 

 has four dimensions all co-equal is not to be discovered by 

 merely generalising Cartesian space equations. (I don't mean 

 by Cartesian space that which Spinoza worked from Exten- 

 sion the one essential property of matter, and Quiet the best 

 glue to stick bodies together). I think it was Jacob Steiner 

 who considered the final cause of space to be the suggestion 

 of new forms of continuity. 



I hope you will continue to trail clouds of glory after 

 you, and tropical air, and be as it were a climate to yourself. 

 I am glad to see you occasionally in Nature. I shall be in 

 London for a few days next week, address Athenaeum 

 Club. 



I think Strutt on sky-blue is very good. It settles 

 Clausius's vesicular theory, 



" for, putting all his words together, 

 'tis 3 blue beans in 1 blue bladder." Mat. Prior. 



The Exp. Phys. at Cambridge is not built yet, but we 

 are going to try. 



1 Royal Institution. 



