OF ARTS AND SCIENCES. 



219 



Calculation oj Correction for Potash Bulb. 



Before After 



Absorption. Absorption. 



"Weight of glass 57.45 grams. 57.45 grams. 



Volume of glass = 57.45 -f- 2.5 . . 23 c. c. 23 c. c. 

 " KOH solution .... 75 " 80 " 



98 103 



« brass weights, lG4-f- 8.2 20 " 



" " •' 173 -^ 8.2 21 « 



Uncompensated volume 78 " 82 " 



Air displaced at 27° C. 

 and 300 teutlis of au inch. 



1.176x78 91.928 m.g. 



1.176x82 96.332 m.g. 



Variation for ^i^ 0.306 " 0.321 " 



The correction of the total weight of carbonic acid for the buoyancy 

 of the atmosphere was not so simj^le a problem ; but by using the 

 same bulb and nearly the same volume of the same solution of potassic 

 hydrate in every case, it was sensibly the same for all the determina- 

 tions. The specific gravity of the solution of potassic hydrate before 

 the absorption was 1.443, and tested in two separate determinations 

 after absorption it w^as found to be 1.464 in each case. Using now 

 the arithmetical means of the weights of the 23otash bulb in the three 

 determinations under consideration, it was easy to find an average 

 value for the correction thus. 



Average weight of potash bulb before absorption 165.02 gr. 



Weight of glass 57.45 " 



solution of KOII 107.57 " 



Volume of solution of KOH == 107.57 -^ 1.443 . 74.55 c. c. 



Average weight of potash bulb after absorption . 173.57 gr. 



Weight of glass 57.45 " 



116.12 " 



Volume of solution of KOII = 116.12 -^ 1.464 . 79.32 c. c. 

 Difference of volume = 79.32 — 74.55 .... 4.77 " 



Weight of CO2 absorbed in potash bulb = 173.57 — 



165.02 8.55 gr. 



