"SOME UNRECOGNIZED LAWS OF NATURE." 783 



packed in cotton in a light glass cylinder, one and three quarter 

 inches diameter by six and a half inches high, and closed the 

 mouth of the cylinder by a flat cork carefully paraffined so as to 

 be air-tight. The apparatus was then placed upright on the bal- 

 ance and counterpoised carefully. The balance beam was then 

 lowered and the apparatus removed from the pan, held inverted 

 for a second or two, and replaced on the pan. On raising the 

 beam and releasing the pans a distinct loss of weight made itself 

 immediately apparent, some seven to nine scale divisions. (The 

 apparatus weighed from one hundred and ten to one hundred and 

 twenty grains.) After some three quarters of an hour the normal 

 weight returned. 



" This loss of weight could not be due to the fact that I was 

 weighing a vessel filled with air partially rarefied by the heat 

 produced, for both vessels were closed air-tight. Nor could it 

 be due to currents of hot air rising (the usual explanation in 

 text-books) for two reasons : first, because the loss of weight was 

 immediate, and, owing to the cotton packing, the outside of the 

 apparatus did not become perceptibly warm to the touch for three 

 quarters of a minute, and never became more than barely warm ; 

 secondly, because the effect noticed was too great to have been 

 produced by convection. ... It would seem, then, that convec- 

 tion currents have been greatly overestimated, and that the loss 

 of weight noticed in weighing hot bodies is in large part a true 

 effect. Either mass is a function of temperature, or else (which 

 is more probable) heat weakens gravitation just as it weakens 

 magnetic attraction, only that the magnetic attraction does not 

 come back when the steel cools." 



Furthermore, the authors show that the combining weights of 

 the elements vary with the temperature, and they record a series 

 of very interesting experiments. When applied to celestial gravi- 

 tation, to the motion of the earth and other planets, and to their 

 apparent irregularities, the new theory leads to surprising conclu- 

 sions. If it stand the test of a more widespread examination, it 

 will entirely change our conception of astronomical physics, and 

 make necessary a radically different cosmology. The specula- 

 tions in this department, however, are put forward very tenta- 

 tively, and more by way of suggestion than as settled convictions. 

 It will be noticed here, as elsewhere throughout the book, that 

 the observed phenomena of Nature are not called in question, but 

 only our conceptions and interpretation of them. 



In conclusion and it is quite time that we should stop we 

 are disposed to believe that Mr. Singer's and Mr. Berens's book is 

 destined to attract wide attention, perhaps to provoke warm con- 

 troversy, and certainly to stimulate wholesome doubt and inquiry. 

 It has a high value quite aside from whether one accepts the 



