346 REPORT OF THE DEPARTMENT OF ENTOMOLOGY OF THE 
has been previously taken, gives the weight. Knowing the weight 
of the mixture taken, the percentage of kerosene can easily be 
calculated. 
Plate No. XXIX gives a view of the apparatus and shows the 
layer of kerosene in the burette. 
PRELIMINARY DISTILLATIONS. 
In order to show that this method was quantitative for kerosene, 
two trial distillations are made. First, 5 c. ec. of kerosene was 
measured into a 500 c. c. flask by means of a pipette and distilled 
with steam for about two hours; at the end of which time it 
was found that the entire 5 c. c. had passed over. <A duplicate 
distillation was made giving precisely the same result. 
Next a small mixture of lime, kerosene and water was made 
up as follows: 
Kerosene yy . fee eae ais. Da Se, TSO eee 10549 Gl 
WV ALR I ceo acs ae Rie Ra a loo Svan ale ew a Pe ee 88.9 ce. 
PAM OS SUR, UA. I 4.5 grams. 
This mixture is in the same relative proportion as the 10 per ct. 
kerosene-lime mixture. In this case, as in the previous experi- 
ment, all of the kerosene passed over. 
These trial distillations show that by this method the entire 
amount of kerosene is obtained. 
DISTILLATION OF LAYERS. ' 
Twenty-five to thirty grams of each of the lower layers were 
weighed out in duplicate and distilled according to the method 
described above. Practically all of the kerosene, about 1 ¢. e. in 
each case, passed over in one hour, but the distillation was con- 
tinued for an hour longer to get the last traces of the oil. 
Fifteen to twenty grams of the upper layer were weighed out 
and distilled in the same way. The time of distillation, however, 
was much longer, from six to eight hours, and 10 to 15 e. e. of 
kerosene passed over. 
Similar distillations of the middle layers were made, but no 
kerosene was found. 

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