RICHARDS AND ROWE. — SPECIFIC HEATS OF LIQUIDS. 185 



sodium lay not merely in showing the small effect of carbonate, but 

 also in verifying the analytical portion of the work. The agreement 

 of the tM'O solutions showed that no numerical mistake had been made 

 in preparing the solutions, and therefore gave much greater reason for 

 confidence in the accuracy of the final results. 



Of the two solutions of potassium hydroxide, the purer was found in 

 two experiments to contain 3.016 and 3.019 percent of the solid sub- 

 stance, and the second less pure solution was found in two other experi- 

 ments to be equivalent to one containing 3.015 and 3.016 percent of 

 pure substance. The average corresponds to the molecular concentra- 

 tion KOH.lOO.lHoO. As usual, weights of solution varying from 93 

 to 132 grams were taken from the weighing burettes in each analysis, 

 hence great accuracy was easily attained. 



Lit h i u m h ydroxide . 



This substance was less easy to prepare, because the material to be 

 had in commerce is very far from satisfactory, as a rule. The sub- 

 stance used in our experiments was of a v^ry high degree of purity, 

 having been made from lithium chloride almost pure enough for the 

 determination of atomic weights. The chloride had been prepared 

 in the first place by Dr. H. H. Willard as one of the preliminary stages 

 of an investigation carried out by him in collaboration with one of us 

 upon the atomic weight of this metal, and its purification has been 

 described elsewhere. We are greatly obliged to him for this help. 

 The salt contained entirely negligible amounts of other bases. After 

 two recrystallizations carried out in order to be sure that no other 

 anions were present, the chloride was converted into the sulphate by 

 heating in a platinum dish with a small excess of very pure sulphuric 

 acid. The pure white salt thus obtained was dissolved in water and 

 the fairly concentrated solution was treated with an excess of hot 

 aqueous barium hydroxide. After settling, the solution was filtered 

 and the excess of barium, determined gravimetrically, was precipitated 

 by precisely the proper quantity of lithium sulphate. The clear 

 solution obtained after settling was decanted in an atmosphere free 

 from carbon dioxide; and after its concentration had been determined, 

 the solution was diluted with enough water, also free from carbon 

 dioxide, to attain the desired concentration. Thus the latter part of 

 the procedure was essentially like that employed in the case of the other 

 alkalies, and the product was strictly comparable with those used in 

 the other cases. In this solution no trace of barium or carljon dioxide 



