202 



THE EARL OF BERKELEY ON SOME 



thermometers. In the expectation of this the total pressures under which each 

 solution was boiling when its density was taken was noted, and is given in the table. 

 This total pressure is made up of the barometric pressure, together with the pressure 

 due to the height of the boiling liquid. To ascertain the effect of the latter, 

 observations were made on the boiling-point of water of varying depths, and through 

 which steam was being rapidly blown. The results showed that the boiling-point was 

 increased by an amount equal to that which a pressure equal to half the depth of the 

 liquid would create ; this, of course, was what was to be anticipated, provided the 

 stirring was thorough. It was assumed that a similar result would hold for the 

 solutions, and the total pressures given are those calculated on this basis. 



Results. 



The first table gives the results obtained by means of the apparatus shown in fig. 5. 



Column I. gives the approximate boiling-point, which is also the temperature at 

 which the py kilometer was filled. 



Column 1 1. gives the total pressure in millimetres of mercury, at the time of filling. 



Columns III. and IV. give the corresponding densities and solubilities; the latter 

 are in parts of anhydrous salt dissolved by 100 parts of water. 



TABLE 1. 



These observations are derived from pyknometer fillings which were considered to be particularly good ; 

 they are therefore given double weight when taking the " means" for the tables at the end of the paper. 



