INJURIOUS INSECTS OF I90Q AND IQIO. 147 
amount (5 oz.) of copper carbonate and use just enough ammonia 
to dissolve it. If the ammonia is strong it should first be diluted 
with water. Then add the proper amount of water (50 gallons). 
ARSENATE OF LEAD. Arsenate of lead is one of the most 
valued of the arsenical insecticides. It has in many cases entirely 
displaced Paris green with orchardists, and there are at least two 
good reasons for it. 
First. The arsenate of lead has great adhesive qualities. It will 
not wash off even in quite heavy showers of rain. Some of our 
experiments here at the Station showed the presence of this arsen- 
ical on the leaf in sufficient quantity to kill insects ten weeks after 
spraying. 
Second. It can be used in any strength without burning the 
foliage of the plant sprayed. 
Third. It has some fungicidal properties that are increased 
when added to Lime Sulphur. 
Arsenate of lead can be made at home or bought in paste form 
on the market. Ordinarily it will be easier to buy the prepared 
material. 
The formula of the home-made is as follows: 
Twenty-two ounces acetate of lead (sugar of lead) dissolved 
in 2 gallons of warm water in wooden pail. 
Eight ounces arsenate of soda dissolved in one gallon warm 
water in another wooden pail. 
These two solutions poured together make a sufficient quantity 
of poison for 50 gallons of spray. ; 
Three pounds of the commercial paste are recommended for 50 
gallons of spray. 
ARSENITE OF LIME. This is essentially a home-made 
preparation. If made properly it is just as good as Paris green 
and is much cheaper. The best method of preparation is as follows: 
White arsenic, one pound. 
Crystal sal soda, four pounds. 
Water, one gallon. 
Boil these in an iron kettle for twenty minutes or until thor- 
oughly dissolved. The kettle must be kept exclusively for this pur- 
pose. The soluble material obtained is arsenate of soda, and can be 
stored away in jugs or bottles, labeled “poison,” for future use. 
