63 
diameter by 12 feet high can be brought to the temperature named 
in from five to ten minutes. When the necessary degree of heat is 
reached, the steain is partly shut off and the mercury maintained at the 
desired point for seven or eight minutes. The tent is then removed. 
On the trees treated to the limit of safety, as described, the red scale 
is killed on the leaves and twigs, but is not affected on the fruit. Itis 
claimed for this process, on which there is no patent, that it is much 
cheaper than the use of gas, and that a 25-horsepower boiler will far- 
nish steam in ten hours for 100 trees averaging 25 feet in height. The 
further advantage claimed for this treatment is that it is said not to 
affect beneficial insects. The objections to the treatment are the neces- 
sity of carrying a cumbersome steam apparatus through the orchard, 
and the fact that the tents are liable to become wet from the steam and 
difficult to handle. It is also less successful than gas, which kills the 
scales on fruit as well as on leaves and twigs. The experiments, how. 
ever, have demonstrated that good results can be obtained, and it is 
possible that in the future something practicable in the destruction of 
scale insects may be accomplished with steam. 
In connection with the experiments with steam a demonstration was 
given of the use of superheated water. This also necessitates the use 
of a boiler, as in the former case. The water which may contain an 
insecticide or be used merely as a hot spray, is raised to a temperature 
in the boiler indicated by 40 pounds pressure. This, when liberated 
through a nozzle at the extremity of a long hose, is equivalent to a 
pressure of about 150 pounds. The liquid escaping from the hose breaks 
up into a forcible half-steam spray even with a very simple nozzle formed 
by a compressed gas pipe, and is directed onto trees as in ordinary 
Spraying operations. The principal advantages are that the spray 
pump is dispensed with and that the liquid is applied at an elevated 
temperature. The spray is, however, cool to the hand in the center of 
the stream at a distance of 18 inches, and on the edges at a distance of 
8 inches from the nozzle, and is not too hot to be borne by the hand at 
a distance of 6 inches from the nozzle. This indicates that the temper- 
ature of the liquid itself will not ordinarily be sufficient to kill the 
insects. This experiment with superheated water was especially inter- 
esting as indicating the futility of attempting to kill insects by means 
of hot sprays. The difficulty of recharging the apparatus and the cost 
of the steam plant will probably render this, as a method of applying 
liquid insecticides, impracticable in comparison with the gasoline-spray 
engines and ordinary spray pumps now in use. 
ARSENICALS AND LIME. 
The advantage of the employment of lime with Paris green or London 
purple having been called in question at the previous meeting of this 
association, the matter was again made the subject of experimental test, 
and the old belief of the decided protective value to the foliage of the 
4 addition of lime was fuily and strikingly demonstrated, 
