All fluids, except water, diminish in bulk till they freeze. Thus,
fill a large thermometer tube with water, say of the temperature of
eighty degrees, and then plunge the bulb into pounded ice and salt,
or any other freezing mixture: the water will go on shrinking in the
tube till it has attained the temperature of about forty degrees; and
then, instead of continuing to contract till it freezes, (as is the
case with all other liquids,) it will be seen slowly to expand and
consequently to rise in the tube until it congeals. In this case, the
expansion below forty degrees, and above forty degrees, seems to be
equal: so that the water will be of the same bulk at thirty-two degrees
as at forty-eight degrees, that is, at eight degrees above or below
forty degrees.