The Pressure Of Sunlight

Prof. Oai-k Maxwell says : "The mean energy in one cubic ioot of sunlight is about 0.0000000882 of a footpound, and the rnenu pressure on a square foot is 0.0000000882 of a pound weight. A flat body exposed to snniight would experience this pressure on lts illuminated ride only, and would tharefore be repelled from the side upon which the light falls. Calcula ted out, this gives the pressure of sunlighfe equul to about two and a half pounds per square milo. Bstween the two and a half poutids deduoed from oalculation aad the fifty-soven tons obtaiced fio-n experiüiöut the differeneo is great, but no greater tbuu is oi'ten tlie case between tUeory aud experiment." Dr. Hblmbold has causad suit to be iastituted against hia brother and others for coiispiring to put him ia. a mad,UüU8O.