THE TOBACCO BEETLE. A] 
ing from 140° to 194° F. The treatment was said to be thoroughly 
effective in killing all stages of the beetle, and cigars made from 
the steamed tobacco were pronounced indistinguishable from those 
made from unsteamed tobacco, the only apparent damage in any 
instance being that steaming the wrapper tobacco made it darker 
and somewhat more brittle. 
EFFECT OF STEAM ON DIFFERENT STAGES OF THE BEETLE—LABORATORY EXPERIMENTS. 
At Richmond, Va. (January, 1915), tests were made to ascertain 
_ the effect of steaming various classes of tobacco infested with the 
beetle. Steam under pressure was admitted directly into a tightly 
closed fumigating drum. Temperature records were obtained by in- 
serting a chemical thermometer through a cork in the lid of the 
drum. The eggs used were on bits of leaf tobacco. Examinations 
of the treated eggs were made after the controls had hatched. All 
tobacco containing other stages of the beetle was put in seperate Jars 
and sealed after treatment. Each lot was kept under observation 
for several months. The results of the experiments may be briefly 
summarized. Thirty-minute exposures at 115°F. gave practically 
negative results. All stages of the beetle were killed by the follow- 
ing exposures: 20 minutes at 160° and 165°F.; 30 minutes at 163°F.; 
1 hour at 138° and 150°F.; 40 minutes at 140°F. 
ULTRA-VIOLET RAYS. 
At the request of a firm manufacturing apparatus for ultra-violet 
sterilization of water, a series of experiments were made to ascertain 
the effect of ultra-violet rays on different stages of the tobacco beetle 
and to determine whether or not the process could be successfully 
used in sterilizing tobacco. Apparatus for the work was installed 
at the laboratory at Clarksville, Tenn.. the equipment consisting 
of a mercury arc rectifier for transformation of 110-volt, 60-cycle 
alternating current to 110-volt direct current, and 2 quartz mercury 
arc burners operated on direct current at 110 volts and consuming 3.5 
amperes. The quartz mercury vapor burners, or lamps, were of differ- 
ent types: One was operated at a voltage of 66-67, consuming 3.3 
amperes of current, and the other at a voltage of 70-75, consuming 3 
amperes of current.1 To avoid any effect of heat, all exposures were 
made with the material in a quartz glass-container under distilled 
water kept at normal room temperatures (quartz glass and chemically 
pure water are transparent to the ultra-violet rays). In experiments 
_ with eggs of the tobacco beetle 3 lots were used in each test, arranged 
as follows: (a) Eggs on upper side of leaf tobacco, (2) eggs on under- 
+The burners were operated under a hood to protect the eyes of the operator from 
jnjury, and glasses were worn as an additional precaution, 
