Absorbed on contact of Liquid ivith Solid. 

 dP 



249 



and J = 4-2x 10 7 , we have ~ =-157; that is, at 7° C. the 



surface-pressure o£ water and silica diminishes at the rate of 

 157 dynes per cm. for an increase of temperature of 1° C. 



From equation (v.) we have -j- + -j- = - nor . ' = '0000037 

 j. i. Mori ds dt 280 



at a temperature or 7 U. j c ^j 



From equation (v.) it is clear that if either ,— or — is 



Oj s ut 



known, the other can be found, and if both of these could be 

 determined with precision, a value for absolute zero could 

 be obtained, which would be independent of the air-thermo- 

 meter. 



IV. 



On the Rate of Variation of the Heat evolved with Change 

 of Temperature. 



The accompanying Table IT. shows the results of experi- 

 ments made to determine, at least approximately, the value of 



Table II. 



Experiments with precipitated Silica. Average diameter of 

 grains '00010 cm. Estimated area of surface per gramme 

 6820 sq. cm. 









Mass ot water, 













Mass of 

 powder 





including water- 







Calories 



Calories 



Number 



Mass of 



equivalent of 



Initial 



Rise of 



per 



per 



of Expe- 



of 



calorimeter, 



Temp. 



Tempe- 



gramme 



sq. cm. 



riment. 





bulb. 



powder, bulb, 



(Cent.). 



' rature. 



of 



of 





grammes. 





tbermometer, 

 and stirrer. 







powder. 



surface. 



1 



3940 



403 



207-26 



7-320 



•136 



7-15 



•00105 



2 



4-282 



3-32 



190-26 



7-300 



•164 



7-29 



•00107 



3 



3760 



3-55 



201-88 



6-930 



•134 



7*19 



•00105 



4 



3602 



3-25 



195-71 



6-238 



•132 



717 



•00105 



5 



3721 



4-00 



196-26 



6-770 



•136 



7-17 



•00105 



6 



3601 



332 



211-49 



7-200 



•122 



717 



•00105 



7 



3-256 



3-58 



205-25 



7-106 



•114 



7'19 



•00105 



8 



9 



4-166 



374 



214-16 



7-502 



•138 



7*09 



•00104 



4-261 



414 



197-01 



23-636 



•164 



7-58 



•00111 



10 



3950 



3-92 



182-94 



24-180 



•162 



7-50 



•00110 



11 



3-657 



3-22 



202-57 



24410 



•138 



7-64 



•00112 



12 



4-789 



4-67 



206-67 



24-000 



•178 



7-68 



00113 



13 



4-417 



3-79 



21202 



24-060 



•160 



7-6S 



00113 



14 



4-691 



317 



230-80 



24-670 



•154 



7-58 



•00111 



15 



4-003 



3-84 



22721 



23-906 



•130 



7-38 



•00108 



16 



3-829 



2-99 



227-68 



24-700 



•124 



7-37 



•00108 



