Manuscript/Mixed Material
Letter from Alexander Graham Bell to Mabel Hubbard Bell, March 28, 1901

M ^rs . A. Graham Bell c/o & Co 6 rue Scribe Paris, France 1331 CONNECTICUT AVENUE, WASHINGTON, D. C. March 28, 1901. My Dear Mabel: —

Your note of March 10 just received in which you say “inaugurate a new departure in book making by publishing a book all pictures just connected by a few words”.

You evidently have been reading my thoughts across the Atlantic, and I suppose you have received ere this my proposition to publish a book of this sort relating to flying machines. I enclose a picture-letter for you relating to rainfall, following out the ideas given in my last letter to Daisy. Haven't time to elaborate, hope you will be able to make something of my notes. I shall simply say: —

(1) That I begin by considering that water-vapor and air cool at the same rate as we go upwards.

The third hypothesis results in the conception of clear atmosphere for a certain height , above which there should be cloud and rain.

I am afraid to say anything more for fear of going on and saying too much. In these diagrams I consider only one point at a time, but each hypothetical condition arouses new queries in the mind. This would result and that would result, and thus the condition