38 George Square, Edinburgh,

10/7/86.

My Dear Stokes,

Is Andrews’ paper in type yet? I ask because Mrs Andrews is desirous of getting private copies.

Can you tell me what was the process, finally determined on between you and Andrews, for finding the absolute compressibility of mercury? I am stopped in my pressure work by this very question or, at least, by a question which can be reduced to this. I will gladly make the experiments. Andrews told me some 13 years ago that you and he had decided on a plan,

Yours truly,

P. G. TAIT.

P.S. Might I send you proofs of a paper on “ Kinetic Theory of Gases”? Cayley was kind enough to look at it in MS., but of course I cannot inflict it on him now.

Sylvester spent the day with me, on his way to seek seclusion, for work, at St Andrews.

38 George Square, Edinburgh,

26/12/89.

I had to get De la Rive's book out of the Library to read the passage you referred to. But it seems to me that you have misapprehended my difficulty. Long ago (1880?) you told me about gravity as the cause of the large separation of the electricities :—and, in my lecture of that year, I spoke of you as holding that opinion. I can find a copy for you without trouble.

What I want, and have been seeking for thirty years at least, is the initial cause of the electrification.