ALCOHOL CHECK EXPERIMENTS. 



103 



DETERMINATION OF CARBON DIOXIDE. 



The computations for the amounts of carbon dioxide are given in 

 Table i. 



TABLE i. Record of Carbon Dioxide in Ventilating Air Current. 

 Alcohol check experiment, April 6-7, 1905. 



In the first column the date on which the experiment was made is 

 given, and in the second column the period, each experiment being 

 subdivided into periods varying from 2 to 12 hours in duration. The 

 amount of carbon dioxide in the chamber at the beginning of the ex- 

 periment is recorded in column a. The subsequent amounts of carbon 

 dioxide found at the end of the periods are recorded beneath this, and 

 corresponding corrections for fluctuations in the residual amounts are 

 recorded in the next column. If, then, these corrections are added or 

 subtracted, as the case may be, to the weights of carbon dioxide ab- 

 sorbed in the absorbing system and recorded in column c, the corrected 

 amount of carbon dioxide produced by the combustion of the alcohol 

 is found. This is recorded in column d. From the computations of 

 the theoretical quantities that should be jaelded from this amount of 

 alcohol, the data in column e are obtained, and the ratio between the 

 amount found and the amount required by theory is expressed in per 

 cent in the last column. 



Obviously, when rather small amounts of alcohol are burned and 

 consequently small amounts of carbon dioxide are evolved per period, 

 slight errors in the determination of the residual amounts may result 

 in a considerable percentage error for the short periods. The errors 

 are compensating, however, for if the residual amount of carbon dioxide 

 found in the chamber at the end of a given period is lower than it should 

 be, the error will affect the total amount produced in the preceding 

 period in one direction and that produced during the subsequent period 



