278 



Scientific Life and Work 



with Mariotte's law, so that the product YP increases 

 slightly as V increases, the contrary is the case with 

 hydrogen, and VP diminishes as Y increases. 



In his seventh memoir which is on the compressibility 

 of liquids, he records experiments, which, from lack of 

 time to perform them thoroughly, afforded no satisfactory 

 results. His reason for giving his results, at all, is charac- 

 teristic. He does not bring them up in order to found a 

 theory upon them, but, to use his own language, " with 

 the view of calling the attention of experimenters to this 

 part of general physics, and with the hope that these 

 observations may be of some use to those who may wish 

 to make a special study of the matter." 



The eighth and longest memoir is on the elastic force 

 of vapor of water at different temperatures. The first 

 part details the experiments made when the temperature 

 was below 50° C. He made in this division alone four- 

 teen series of experiments, comprising 464 separate obser- 

 vations. The temperatures range from —30° to + 50°, and 

 for any one temperature there are several determinations. 

 He paid special attention to the determination of the ten- 

 sion of vapor when at the freezing point, making sixty- 

 four observations on this value alone. 



Then follow four series of observations, containing 150 

 determinations, and comprising temperatures from 40° to 

 100°. The next set of observations includes three series 

 of 94 determinations, in which the temperatures range 

 from 100° to 140°, and six series of 232 determinations, 

 for temperatures between 100° and 230°. 



In another part of the memoir he combines this im- 

 mense mass of numbers, and after constructing a curve 

 which represents graphically the relation between tem- 

 perature and tension, discusses the formulae which have 

 been proposed to indicate this relation algebraically. He 

 settles on the following formula as corresponding very 



