Elementary natural philosophy : designed for high schools and academies (1881)
Griffin, La Roy F. (La Roy Freese), 1844-1916 · Philadelphia : Sower, Potts & Co. · leaf 99
ns more matter than one more dense, but whichweighed in air seems to have the same weight. Or a grammeof feathers is actually heavier than a gramme of lead, be-cause the lead contains more matter in the same volume,and is to that extent less porous. The pores of solids may be shown readily by… … the eye. A clean cut across the pores with a knife showsa surface like silver. 308. Balloons. The buoyancyof the air causes the rise of bal-loons. A Balloon, Fig. 116, is apear-shaped sack made of strongoiled silk, and filled with somegas much lighter than the air.Hydrogen is the lightest gas,…
Physics
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