206 MESSRS. A. V. HAECOUET AND W. ESSON ON THE LAWS OF CONNEXION 



escaped the slow action of oxalic acid are instantaneously reduced, leaving in their stead 

 so many molecules of iodine, which are without action on any ingredient of the solu- 

 tion and can therefore be estimated at leisure. By using a very dilute solution of 

 hyposulphite, and a freshly prepared and filtered solution of starch, the subsequent deter- 

 mination may be performed vnth a high degree of accuracy. Some of the measured 

 quantities of the mixed solution were always reserved for a repetition of previous experi- 

 ments ; in several instances the whole series was performed twice. In these latter sets 

 the readings of the burette, after two similar experiments, seldom differed by more than 

 0"15 cub. centim. From time to time the value of the measure of permanganate was 

 taken in terms of the solution of hyposulphite, and the numbers given in the Tables as 

 the percentage of residue are obtained by multiplying the actual readings on the burette 

 by 100, and dividing by this number. 



The following Table contains the results of fifteen series of experiments thus con- 

 ducted. Their object was twofold, to establish by a sufficient induction the true course 

 of the reaction, and to discover by a comparison of the different series the relation 

 between the rate of change and the quantity of sulphuric acid employed. The curves 

 representing this series of experiments will be found on Plate XVIII. fig. 1. 



Table VIII. 



K2Mn2O8+14MnSO4+108H2C2O4+%(76H2SO4). 



Volume of solution 200 cub. centims. Temperature 16° C. Time x mins. 



