44G STATE BOARD OF AGRICULTURE. 



volume which would be given at 0°C. and 7G0 m. m. mercury pressure so 

 that they might be safely compared. The second reading, then, minus 

 the third (in each set of reduced readings) showed the volume of carbon 

 dioxide i)roduccd during the period; and since no carbon dioxide was 

 present at the beginning, the first reading minus the third gave the 

 volume of oxygen that had been absorbed during the test. The volume of 

 oxygen absorbed in the case of the insecticide-treated "extract plus hy- 

 droquinone" and the volume of oxygen absorbed by the untreated "ex- 

 tract plus hydroquinone" could thus be compared directly; and it is 

 believed that any difference must be attributed to the influence of the 

 insecticide present, since other conditions were kept as nearly as pos- 

 sible the same. 



Checks tried separately had shown that gasoline and carbon disul- 

 phide vapors were not appreciably affected by the potassium hydroxide 

 solution used, and that they did not interfere with its absorption of 

 carbon dioxide. 



The records of a test are given here as they were kept for a regular 

 experiment : 



Exp. 7. Used 5 c. c. of an extract (made from 4 large "white grubs" in 20 c. c. distilled water, 

 plus 3 drops of Toluol) in each of the two containers — right and left. 



N 



Ran pump at intervals until readings became constant. Added 2 c. c. or r— ^ hydroquinone solu- 

 tion to each. Ran pumps short interval — readings were constant. ^"" 



started 17 Aug. 1912, 4:45 P. M. 

 Ended 18 Aug. 1912, 8:00 A. M. 



At start —Bar. =740 m.m.; Temp. =19.3° C. 

 At end — " =734 rn'm.; " =20.4° C. 



Ext. =Left-hand system (CS2 — treated). Ext. =Right-hand system (no treatment). 



Gas-burette reading 



27.5 c.c. 



30.5 



27.5 



Gas-burette reading 



20.5 c.c. 



23.5 



20.5 



Readings reduced to 760 m.m. mercury pressure and 0°C: — 

 Left-hand system (CS2 — treated). 



430 c.c. =Volume of left-hand system, exclusive of gas-burette. 

 27.5 c.c. = Volume of gas in left-hand gas-burette. 



457.5 c.c. = Total volume of left-hand system at start. 

 457 (740-16.655)273 



760(273-1-19.3) 

 430.0 c.c. 

 30.5 



=406.6 c.c. vol. at start (reduced). 



460.5 =Total vol. at end of test; before CO2 had been absorbed. 

 460.5 (734-17.826)273 



760(273 -f 20.4) 



=403.7 c.c. Vol. before GO2 had been absorbed (reduced). 



430.0 

 27.5 



457.5 =Total vol. at end of test (after CO2 was absorbed). 

 457.5(734-17.826)273 



760(273+20.4) 



Then 406 . 6 

 401.1 



=401.1 Vol. at end of the test (reduced). 



5.5 c.c. O2 absorbed during test by the "extract plus hydroquinone" in the presence of CS% 

 vapor in air. 



