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COHESION.
ice. Here you see the tin dish is frozen to the board, I can even lift this little stool up by it.
This experiment cannot, I think, fail to impress upon your minds the fact, that whenever a solid body loses some of that force of attraction by means of which it remains solid, heat is absorbed; and if, on the other hand, we convert a liquid into a solid, e.g. water into ice, a corresponding amount of heat is given out. I have an experiment showing this to be the case. Here (fig. 21) is a bulb, A, filled with air.
Fig. 21.
the tube from which dips into some coloured liquid in the vessel B. And I dare say you know that if I put my hand on the bulb A, and warm it, the coloured liquid which is now
