An Investigation of a Case of gradual Chemical Change. 405 



further investigation, viz., the action of hydrogen chloride on potas- 

 sium chlorate. 



In this reaction we examine the effect on the rate of variation in 

 the amount of hydrogen chloride, the potassium chlorate being kept 

 constant. We then briefly touch on the results obtained by varying 

 the potassium chlorate. 



We next consider the effect of variation in the amount of potas- 

 sium iodide present, used as an indicator of the performance of a 

 definite amount of chemical work. 



We lastly discuss the effect of variation in the temperature at 

 which the reaction of hydrogen chloride and hydrogen chlorate takes 

 place. 



Variation in Hydrogen Chlorate. 



A series of observations were made in which the quantity of 

 hydrogen chlorate was varied in arithmetical progression, the hydrogen 

 chloride being kept constant. When each of the numbers repre- 

 senting velocity of decomposition was divided by a number represent- 

 ing the amount of hydrogen chlorate present, the series of numbers 

 obtained, was approximately an arithmetical progression, the differ- 

 ence being a small one. So that if u represents the hydrogen 

 chlorate, R the rate of decomposition, a formula by which the latter 

 may be calculated from the former is of the form 



where A and B are constants. 



The following tables contain examples of the results obtained by 

 experiment, and by calculation from this formula. 



The rate = the number of times the following reaction in millionth 

 of a gram-units takes place in each c.c. per minute. 



6HC1 + 6KI + KC10 3 = 



HC1 = 16 x 65'11 millionth-gram-molecules in each c.c. 



HC10 3 = 



u varies from 2 to 6. 



Table I. 



