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"Grease the edges to make more sure of a tight joint, fit the hemispheres to each other, and exhaust the air with a pump. Close the stopcock, remove the hemispheres from the pump, attach the second handle, and, holding the hemispheres in different positions, try to pull them apart. When you are sure that the pressure that holds them together is exerted inall directions, place them under the receiver of the air pump, and exhaust the air from around them. The pressure seems to be removed, for the hemispheres fall apart of their own weight." -Avery 1895

Magdeburg Hemispheres

"Grease the edges to make more sure of a tight joint, fit the hemispheres to each other, and exhaust…

"Tenacity is that property of matter by virtue of which some bodies resist a force tending to pull their particles asunder Its measure is the ratio between the breaking weight and the area of the cross section of the body broken. It varies with different substances, with the form of the body, with the temperature, and with the duration of the pull." -Avery 1895

Testing for Tenacity

"Tenacity is that property of matter by virtue of which some bodies resist a force tending to pull their…