182 REPORT OF THE 



•2603.88 



6. S= " G=oo , S=o 



(a -|- 4.454 



6. 8=3.846 B « B=o,S=o 



7. £=3.885 s « s=o,S=o 



585.516 



8. S=585.516 " g=l,S=o 



g 

 677.008 



9. b== " G=a>,B=o 



G -|- 4.454 



10. B=.26S " S=o,B=o 



11. B=1.01s " s=o,B=o 



152 



12. B=152 " g=l,B=o 



g 

 670.218 



13. s= " G=oo , s=o 



G _|- 4.454 



But knowing the mean specific gravity of salt to be 2.125, we may also calculate the spe- 

 cific gravity of the saturated solution (without allowance for condensation) from the per 

 centage of salt, by means of formula (2). This gives 

 g'=1.1560 

 It is evident, therefore, that Dr. Ure's value of the condensation is too great, or else his 

 per centage of salt in satur ted brine is too great. But that per centage is less than given 

 by most other authorities, while by my own experiments upon commercial salt, it amounts 

 to 26.595. 



Again, according to the experiments of MM. Francoeur and Dulong, when a brine con- 

 tains 10 per cent, of salt, its specific gravity is 1.0735; and when it contains 15 per cent., it 

 is 1.1094. Now if we assume 10 for the per centage of salt in Eq. (1), we get 

 g'=1.0559, instead of 1.0735. 

 If we assume 15 for the per centage of salt, 



g'=1.0862, instead of 1.1094. 

 The increased specific gravity due to condensation in the first case, is .0186=. 186 per 

 cent, of 10, the per centage of salt. 

 In the second case, it is .0232=155 per cent, of 15, the per centage of salt. 

 Further, in the case of saturated brine, it is .049=. 191 per cent, of 25.5, the per centage 



of salt. The first and last values are sufficiently cousonant, but not so the second. The 



mean of the first and last is .188 per cent. Assuming this 

 g=g'-|- .00186 s 

 Substituting the value of g' from Eq. (2), we might thence deduce s in terms of g. 

 Another view may be taken of this subject. It is evident that we may regard all the con- 

 densation as taking place in the salt ; and tne result will be the same if we imagine it to 

 take place before the solution. We may then proceed to calculate what value of the specific 

 gravity of the salt would be requisite in order to produce, without further condensation, a 

 brine of a given specific gravity, and containing a given per centage of salt. 

 If in (2) we make g'=1.0735, w=90, s=10 and 2.125=x, we get 



x=3.186. 

 If in (2) we make g'=1.094, w=85, s=15, and put x for k 2.125, we get 



x=2.919. 

 If again we mike g'=1.205, w=74.5, s=25.5, 



x=2.838. 

 These results are but little accordant ; and show that the condensation is not proportional 

 to the per centage of salt, or else that errors exist in the data. The mean of the three values 

 is 2.981. 



If now in Eq. (2) we substitute 2.981 for 2.125, g' ought to become g, when we should 

 have 



100 100 150.478 



g= = (3) 



s s . 150.478 — s 



w _| 100— s -| 



2.981 2.981 



Whence, also, 



150.478 

 8—150.478 (4) 



