Alexander G. McAdie


John Muir


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in these currents were made to float, or rest in equilibrium. So he found out a great deal about the way in which [illegible]fall and measured their velocities. The greatest velocity was about 8 meters per second, say 26 feet. The first effect of the current of air on the shape of the drop was to flatten it, then he was able to cause circulations or vortex movements around the drops (I have seen the same thing happen in a drop of dew, which was slowly evaporating. A speck of dust whirlled around and round the equator of the drop. I am working on this now with a microscope and may get some illustrations latin • Lenard found that the fine drops are far in excess of large drops;and they don't change in a regular gradation; but gather in groups. Sometimes the intermediate sizes are missing. Now what happens within the cloud mass. Something akin to the smallest rain drops evidently forms and float with others of their kind. There can be in one cubic inch of cloud mass, a million and more of these little drops, trying to get away; but too light and too small in their own proper selves to have much motion. Physicists think that under certain conditions an electrification of the drop occurs, and by a series of strong attractions and repulsions04734


San Francisco

Date Original

1910 Mar 19


Original letter dimensions: 25 x 20 cm.

Resource Identifier


File Identifier

Reel 19, Image 0259

Copyright Statement

Some letters written to John Muir may be protected by the U.S. Copyright Law (Title 17, U.S.C.). Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Responsibility for any use rests exclusively with the user.

Owning Institution

University of the Pacific Library Holt-Atherton Special Collections. Please contact this institution directly to obtain copies of the images or permission to publish or use them beyond educational purposes.

Page Number

Page 3


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