280 



Scientific Life and Work 



brought to coincide. We see then that Regnault did 

 wisely in multiplying observations so as to eliminate those 

 slight anomalies and errors which are the bane of every 

 experimenter in physics. 



The ninth memoir contains his experiments on the 

 latent heat of the vapor of water. For the equivalent of 

 this he obtained as the mean of forty-four observations, 

 the value 636.67 kilogram-degrees. This w^as for vapor 

 at atmospheric pressure, but the memoir also describes 

 seventy-three experiments to determine the latent heat 

 when the pressure varied from 1 to 13.6 atmospheres, 

 twenty- three experiments with pressures of .2 to .66 at- 

 mosphere, and twenty-two experiments when the range 

 was from four to twelve millimetres. This memoir offers 

 a direct determination of the second datum of his origi- 

 nal problem, as the preceding memoir, accomplished the 

 determination of the first. 



The tenth and last memoir determines the specific heat of 

 water at various temperatures by means of forty experi- 

 ments, and thus fixes the third datum of the general problem. 



Such are the contents of this one contribution to the 

 science of heat, containing in itself more accurate and 

 more abundant results than are usually afforded by the 

 scientific labors of a life-time. These memoirs, more- 

 over, are valuable not merely as a record of what Regnault 

 himself accomplished, but also as containing an impartial 

 account of all previous investigations, in the same field, 

 including the labors of Rumford, Black, Dalton, Gay- 

 Lussac, Dumas, Dulong, Petit and others. In treating 

 his predecessors' work he is always fair-minded and 

 never tries to arrogate to himself the praise due to others. 

 He recognized the fact that truth not fame must be the 

 object of scientific endeavor. 



In this cursory review of Regnault's great work, all the 

 details, which illustrate his patience, his ingenuity, and 



