Page:Various Forces of Matter.djvu/117

Rh this spirit-lamp it will only go in the gauge or through the hole with difficulty; and if I were to put it into boiling-water it would not go through at all. Again; as soon as the heat escapes from bodies they collapse; see how the air is contracting in the vessel now that Mr. Anderson has taken away his lamp: the stem of it is filling with water. Notice too, now, that although I cannot get the tube through this hole or into the gauge, the moment I cool it by dipping it into water, it goes through with perfect facility, so that we have a perfect proof of this power of heat to contract and expand bodies.