Department of Chemical Research. 



The curves of these substances are all drawn upon the same 

 scale of magnitude as those of the " strong " solutions of the 

 corresponding acids. They show : — 1st. A much greater 

 increase of the electromotive force caused by the first amount 

 of substance added than by the subsequent ones. 2nd. A 

 gradation of degree of first increase and of maximum electro- 

 motive force, varying inversely as the magnitudes of mole- 

 cular weight of the substances. 3rd. Large differences of 

 form, characteristic of each individual substance. And 4th. 

 The substitution of potassium for hydrogen in the correspond- 

 ing acids lowered the electromotive force in all three cases, and 

 the amount of this reduction varied inversely as the magni- 

 tudes of the molecular weights of the substances ; the union 

 of potassium with the halogens had similar effects, but in 

 much greater degrees (compare the respective figures). 



8. Curveo/KBrat60° C. 



The range of degrees of strength of the solution in this case 

 was the same as in the previous one when the liquid was at 

 18° C, and was from *10 to 1*0 grains of substance in 155 

 grains of water. 



2 I 2 



