WCP2900

[1]

Minsmere

Dunwich

Saxmundham

Jany 24th 1908

Dear Sir,

I am much obliged to you for your note¹ & have ordered your book on Mars.²

It is not clear ^{to me} how any estimate can be made of anything beyond the average velocity of gas molecules & provided the average is well within the limit it will still remain an open question, so [2] far as the kinetic theory goes, whether there is or is not water vapour in a planet. I suppose (& Lowell³clearly enough admits this) that Mars has been & still is, chemically wasting its water vapour – hence its present dryness. Its absence of mountains probably come from the terrific sweeps of its little near-noon tides. I remember noting that Lowell said in his first book that Mars⁴ wd have no tides to speak of but as far as I could calculate in a rough way the neaerer moon (? Photos [illeg.]) [3] has a tremendous tide-producing proves far greater relativity than our own.

What made me lock the question of water vapour in Mars up was that when staying in B'ham I was reading Young's⁵ Astronomy & then found it states that Sir W^m Huggins⁶ had found undeniable spectroscope proof of the existence of water on Mars.

very truly yours, | James A Aldis⁷ [signature]

Dr. Alfred R Wallace.

[4]⁸