440 APPENDIX. 



160. 



The numbers given in the text are only approximations. 

 The exact quantities may be readily calculated by the law 

 of expansion and contraction of gases, and vapors previously 

 given, taking the volume of steam at 212 ( 232,) as a start- 

 ing point. 



232. 



According to the most recent determination, by Regnault, 

 the latent heat of steam is 966'6. According to the same 

 experimenter the sum of the latent and sensible heat is not 

 rigorously constant. 



235. 



The apparatus commonly employed in the laboratory for 

 distillation, consists of 

 a retort and receiver, 

 as represented in the 

 figure. In Liebig's ap- 

 paratus, for the same 

 purpose, the vapors are 

 made to pass from the 

 retort or flask through 

 a long inclined tube. The latter is enclosed in a second tube, 

 which is constantly supplied with cold water. A more per- 

 fect condensation is thus effected. 



248. 



ACTIVE FORCE or THE GALVANIC CURRENT. The active 

 force of the galvanic current, is directly as the whole electro- 

 motive force in operation, and inversely as the sum of all the 



