area 



or 



Mr. J. J. Hood on the Laws of Chemical Change. 377 



As a criterion of the probability of the supposed law, I have 

 calculated the areas enclosed between the curve y(a + t) = b, 

 axis y, and asymptote t, with the limits for time of last obser- 

 vation and zero, on the supposition that the law holds good 

 between the two observations selected to determine a and b. 



Thus 



: I yalt 



Mog e 101og 10 (l+£), 



taking log 6 10 = 2-3026. 



The areas were also calculated from the experimental num- 

 bers by the formula 



area =2 (**£&) (*»+.-<»), 



which is approximately true, independently of any law. The 

 results are given below with the percentage differences of 

 " found " from theory. As the curve is convex to axis t, it is 

 evident that the areas calculated by the latter formula should 

 be slightly greater than theory. 



Areas. 





Theory. 



Found. 



Percentage 

 difference. 



No. 1 



2346-8 

 4219 

 1937-3 

 1952-6 



2362-4 

 4239-9 

 1962-5 

 1964-7 



•66 



•50 



1-24 



•62 



„ 2 



„ 3 



„ 4 





The question now arises, What will be the form of the equa- 

 tion representing the change when there is an excess of either 

 of the active bodies present? Taking equation (1), 



J =«(A-«)(B-/3), 



and supposing there is an excess of B sufficient to act on n 

 times the amount of A present, then, as before, B = ynA, and 

 also (S=va. Since the amount of B rendered inactive is pro- 

 portional to that of A up to any time, the above equation 

 becomes 



den , . 



a)(nA— «). 



(5; 



