The book of stars; being a simple explanation of the stars and their uses to boy life, written to conform to the tests of the Boy scouts (1915)
Collins, A. Frederick (Archie Frederick), 1869- · New York, D. Appleton and company · leaf 54
th of the tube, turn it upsidedown and put the open end into a cup, or other vessel, whichis half full of mercury; in placing it into the cup be careful thatno air gets into the tube. Only a small part of the mercury in the tube will run intothe cup and this will leave a space in the top of the… … Fig. 34.—Sun Spot in Photosphere 36 THE BOOK OF THE STARS Since the air presses on the mercury in the cup but not inthe tube, the pressure of the air on the mercury in the cup justbalances the weight of the mercury in the tube and, hence, anyincrease or decrease in the pressure of the air, which…
Astronomy · Stars
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