HEAT HAS WEIGHT

Evening Post, Volume CX, Issue 112, 8 November 1930, Page 25

HEAT HAS WEIGHT

which indicate about hew much weight the mere fact of being hot will add to ! samples of simple kinds of matter. The additional heat-weight is very tiny in amount, probably too small to be detected by any present method of weighing or other physical experiment. Professor Tolman, believes, however,, that his deduction of a relation between heat and the gravitation properties of matter is not only important as an item of pure physical theory, but may" have significant theoretical or practical applications to some of the things that go on in the universe, like i the generation and distribution of energy in stars, tho properties of gas- J eous nobulae in space, and others. It! is not even impossible, ho suggests, that tho weighing of heat may bo accomplished some> day by laboratory ex-, poriment. j

That, heat' has weight, so that a bil- ' lion atoms of hot lead, for example, 1 weigh an infinitestinial triflo more than t tho same metal when it is cold, is a recent deduction'from , the Einstein 1 theories of /.relativity, Communicated 1 to the American Physical Society by ■> Professor Kichard' 6.' dolman, of the : California Institute' ofTechnology. 1 That light has weight,is an. earlier i , and more familiar deduction from these ' 1 same theories, '.upon which deduction ' was based tho estimated bending of -, light ray^ from distant,stars as these , rays pass V.lose to tho sun, one of the 1 so-called proofs' of the' Einstein theo- < ries tested at recent total eclipses of ( the sun. Much the same reasoning ap- - plies •» to tho probable weight of heat, 1 and professor Tolman has worked out < complicated mathematical equations ]