20 BULLETIN 875, U. S. DEPARTMENT OF AGRICULTURE. 
take weevil poisoning by the use of a number of hand guns on this 
area. This has generally proved very unsatisfactory. The labor re- 
quirements of the guns are so great and the operation so laborious 
and difficult that labor troubles are certain to develop under any nor- 
mal condition and this has generally resulted in preventing anything 
like a satisfactory schedule for poisoning work. 
One important use of the hand gun is in conjunction with power 
machinery. A great many fields have certain portions which are 
very difficult to treat with power machinery, owing to the presence 
of ditches, stumps, short rows, or similar obstacles. Attempts to 
treat these portions of the fields with large machinery greatly reduce - 
the rapidity of the operation of the machine and frequently the cot- 
ton 1s injured by being tramped and driven over. Under such condi- 
tions the efficiency of the large machine is much increased if a few 
hand guns with which to treat these difficult portions are available 
for use at intervals. 
Hand guns are also of great value for the early-season work in 
treating isolated spots of infestation which are often comparatively 
small in extent. In much of the work which has been conducted in 
the past, hand guns have been used in such fields for the first appli- 
cation or two and a sufficient degree of control secured from this 
work to make it possible to defer starting general poisoning with a 
large machine until some weeks later than. would otherwise have 
been the case. 
Several instances have been noted where hand machines have been 
offered for cotton dusting purposes with the distributing system di- 
vided between two nozzles, the idea being that two rows could be 
treated at each trip. None of the machines manufactured at present 
have more than enough fan power to treat a single row satisfactorily. 
A number of hand guns have been offered for use in cotton dusting 
with the blower constructed so that the dust delivery is intermittent. 
As such guns are usually equipped with a bellows serving as a blower 
the powder is expelled only in recurrent blasts. These are not satis- 
factory for cotton work since it is necessary that the gun discharge 
the dust continuously in order that uniform poisoning of all plants 
be secured while the operator proceeds along the row. 
As has been stated, hand-gun work is mainly conducted in the 
early morning and late evening, and this limits very much the 
amount of territory which can be covered each day. Operation dur- 
ing the night, however, is often entirely feasible and the results 
from such operations are usually better than where treatments are 
attempted during the day. Very satisfactory hand dusting can be 
done at night by the aid of a small oil or carbide hght attached to the 
hat of each operator, or, in some cases, several hand guns may be 
a 
