B M. Gay-Lnssac on the [Jan. 



Soluhility of Chloride of Potassium. 



Temperature Chloride dissolved by 



centigrade. 100 water. 



0-00*' 29-21 



19-35 34-53 



52-39 43-59 



79-58 50-93 



109-60 59-26 



If we construct these results, taking the degrees of temperature 

 for abscissas, and the quantities of salt dissolved by 100 water 

 for ordinates, we shall see that they can be represented by a 

 straight line. To find its equation, I have supposed the ordi- 

 nate 34-53 corresponding to 19-35° to be constant, because the 

 experiments on solubility at mean temperatures should in general 

 be more accurate than those made at temperatures at a great 

 distance from them, and a straight line was made to pass suc- 

 cessively by the extremity of each ordinate representing the 

 solubility. There resulted for the tangent of the angle which 

 the straight line makes with the hne of abscissas the following 

 values : 



0-2749; 0-2742; 0-2723; 0-2740; 



the mean of which is 0-2738. Of consequence, the equation of 

 the line of solubihty of the chloride of potassium will be : 



y = 0-2738 x° + 29-23 



It may be employed with certainty to find the solubihty of 

 chloride of potassium at all temperatures comprehended between 

 the two extremes 0° and 109-6°; but in all probabihty it would 

 not serve for temperatures much more elevated, or much lower. 

 This equation is constmcted in Plate C, under the name of chlo- 

 ride of potassium. By means of the division of the hnes on 

 which are counted the temperatures and solubilities, it will be 

 easy to find vidthout calculation the corresponding solubility at a 

 determinate temperature. 



Solubility of Chloride of Barium. 



Temperature centigrade. Salt dissolved in 100 water. 



15-64° 34-86 



49-31 43-84 



74-89 , 50-94 



105-48 59-58 



the equation of the line of solubility is, 



y = 0-2711 a' + 30-62 



In these experiments, the chloride of barium is supposed to be 

 anhydrous ; but as when it is crystallized it retains two propor- 

 tions of water, 22-65, for one of chloride, 131-1, we must of 



