New York AGRICULTURAL EXPERIMENT STATION. 763 
insects eat the poisons before they can be injured by them, hence 
the first class of insecticides can not be used for all insects. The 
second class may be used on all insects but is far from practical 
in many cases. 
The unpatented remedies of the first class are: “‘ Paris green,” 
Arsenite of copper, “ London purple,” Arsenite of lime, 
and “Gypsine” or Arsenate of lead. These are sometimes 
spoken of as the “ Arsenites.” They can be used in dry powder 
form or with water. When used in powder form they should 
be mixed with flour, road-dust, or land plaster, at the rate of one 
part of the poison to 15 or 20 parts of flour or plaster. 
Lormula for water mixtures. 
Faris green or London purple ........... 1 pound. 
Lime unslaked .... .. Ay ee MURR Paes ws 16 pounds. 
WG Ra CEL CZAR Vl 160 gallons, 
Slack the lime and add to the Paris green with sufficient water 
to make 160 gallons. 
Formula for Gypsine. 
Lead! acetate (sugar of lead).............. 11 ounces. 
Rememstiae OL SOUR NP is ee ot 4 ounces. 
SRE AE oestees BID ERS A eee 160 gallons. 
For cabbage insects it is best to use the arsenites in water. 
Milk of lime should be made from water-slaked lime. The lime 
not only prevents any injury to the foliage by the arsenite, but 
also aids in making the poison adhere to it. 
_“Gypsine” is one of the remedies used by Gypsy Moth Com- 
mission of Massachusetts. It needs to be tested more thoroughly 
before being recommended for general use. Its principal advan- 
tage lies in the fact that it does not injure the foliage. 
Paris green ought to be purchased at 25 to 35 cents per pound, 
depending on the quantities purchased. London purple should 
not cost over 10 to 12 cents per pound. For making ‘‘ Gypsine” 
sugar of lead can be purchased at 14 to 18 cents per pound, and 
arsenate of soda at 8 to 10 cents per pound. 
The principal insecticides of the second class are kerosene 
washes, resin wash, bisulphide of carbon, tobacco and hot water 
