224 NEW YORK STATE MUSEUM 
london purple and another the reverse. Yet both have been the object 
of considerable experimentation and are of nearly equal value, though the 
latter is said to be more variable in composition. The same may be said 
of kerosene emulsion and a whale oil soap solution. In the case of these 
preparations, it is alvays advantageous to make a few tests. To a certain 
extent a man may depend upon the experience of others, but he should 
also ascertain by trial what proportions, with his own apparatus and under 
the conditions at hand, will give the best results. 
Arsenical compounds. These are effective against insects which 
devour portions of a plant and of value only when placed where they will 
be eaten. The following formulae are commonly employed: 
Rams OLEH a Seis ote ts ere 6 hats ope aen Gre oleate Oe 1 pound 
irc LM eS pat ate a cco es a ick Race Ne Pee Me a SERIES r pound 
Watereec— .:: DES ae ed oe ee Sere cack 100-300 gallons 
Hondon apunples: jet ak. See Mole eei Seen eeae ee eepeeee I pound 
Giniekalinie 2a aah oe icy ate aly fe dred ope Re sete 2—3 pounds 
Water yee Sect Nie tN bose ssavepstoriels deo teheag Oe ee 100-300 gallons 
The more common proportion is at the rate of 1 pound of the poison 
to 150 or 200 gallons of water, and less should be used on the more tender 
foliage like that of the peach or there may be serious injury. The addi- 
tion of lime is not necessary, specially with paris green, but is a wise 
precaution as is neutralizes any free arsenic acid and thus prevents burn- 
ing. Paris green can be applied with the bordeaux mixture,* at the rate 
of 4 ounces of the poison to 50 gallons of the fungicide, and in this 
preparation both fungi and many insects find an effective check. 
If desired, paris green or london purple can be dusted on low plants, 
such as potatoes and asparagus, when they are wet with dew, pro- 
vided the poison is diluted with from 50 to roo parts of flour or land 
plaster. 
Another substance which has received high praise and may come into 
general use after its good qualities become better known, is the arsenate 
of lead. The value of this compound as an insecticide has been 

a The following formula is taken from Bxdletin 114, Cornell university agricultural experi- 
mient station - 
Normal or 1.6% Bordeaux mixture: 
Copper sulfate, 6 pounds 
Quicklime, 4 pounds 
Water, 40-50 gallons. 
Dissolve the copper sulfate by putting it in a bag of coarse cloth and hanging in a vessel con- 
taining at least 4 gailons of water, so that it will be just covered. Usean earthen or wooden 
vessel. Slake the lime in an equal amount of water. Then mix the two and add enough water 
to make 4o gallons. It is then ready for immediate use. If the mixture is to be used on peach 
foliage it is advisable to add 2 pounds of lime to the above formula. 
