1819.] Scientific Intelligence. 151 
XIII. Effect of Common Salt on the Solubility of Nitre in Water. 
A curious set of experiments on this subject has been recently 
published by M. Longchamp. I shall here state some of the most 
remarkable facts which he has ascertained. 
At the temperature of 39°, the specific gravity of a saturated 
solution of nitre and common salt is 13057. It is composed of 
Waters cue. ele ases OL Te 
Nitre'd tenddias HOPED Soe SONG DO 
Common salt. ......... 22-20 
100-00 
Now 61-74 parts of water, of the temperature 39°, are capable 
of dissolving only 9-823 parts of nitre ; so that the solubility of 
the nitre was increased by the presence of the common salt in 
the ratio of 153 to 100. Probably at lower temperatures, the 
solubility of nitre in water would be doubled by the presence of 
common salt. 
At the temperature of 642°, the sp. gr. of a saturated solution 
of nitre in distilled water is 1:151. It is composed of 
Weiter pees sooo. We a ee 
Nitta ers Sess Sacro od tee 
—— 
100-00 
The following table exhibits the effect of the addition of 
common salt (added in different proportions) upon the power of 
such a solution to dissolve additional quantities of nitre. The 
temperature is always supposed to be 644°. The first column 
gives the quantity of solution of nitre employed ; the second that 
of common salt added ; the third that of the-nitre dissolved, in 
consequence of the presence of the common salt; the fourth 
that of the nitre in solution in the liquid employed ; the fifth the 
total of saltpetre in the liquid, including both the original quantity 
and the new quantity rendered soluble by the common salt. 
The sixth column gives the specific gravity of this compound 
liquid, containing both nitre and common salt. 
Quantity o Nitre dissoly- 
solutions of| Common |ed by means Nitre in the 
original solu- Total _nitre|Sp. gr. of the 
nitre em-}salt added. \of thecommon)|.. dissolved. solutions. 
ployed. salt, map. 
Grammes, | Grammes, Grammes, Grammes, Grammes, Grammes, 
100 5:00 0°746 21.63 22°376 11871 
100 10°00 1267 21°63 22°897 4°2212 
100 15-00 1°658 21°63 23-288 12523 
100 20°00 1'827 21°63 23-457 12832 
100 25:00 2°583 21:63 24-213 13096 
100 26°85 3-220 21-63 24°850 1-3290 
M. Longchamp considers this increased solubility of the nitre 
3 
