42 



HYGROMETRICAL TABLES. 



A third series of miscellaneous tables furnishes the means of comparing the differ- 

 ent values of the elastic force and weight of vapor determined by various physicists, 

 as well as the results of Saussure's Hair- Hygrometer, with those obtained by other 

 methods. 



An Appendix, containing tables for comparing the quantity of rain-water indicated 

 in different measures, closes the set. 



Though the first series of tables, based on Regnault's table of tensions, is recom- 

 mended for ordinary use, as being derived from the determinations which seem to 

 deserve the greatest degree of confidence, it was thought expedient to give also the 

 Greenwich tables, which have been, and still are, so extensively used in England, in 

 order to enable meteorologists to judge of the differences which exist between the 

 results obtained by them and those deduced from the constants of Regnault and 

 others. 



B 



