INSECTS AND INSECTICIDES 
33 
7 - LONDON PURPLE. 
London purple is a by-prodnct in the manufacture of aniline 
dyes and has for its active principle arsenite of lime. It also con¬ 
tains some free arsenic, lime, coloring matter and other impurities. 
The amount of arsenic present is subject to considerable variation, 
but will usually range between 40 and 55 per cent. As there is 
often considerable soluble arsenic present, it is always best to use 
a pound or two of freshly slacked lime with every pound of the 
poison if used in water. 
This poison is finely divided and remains in suspension in 
water much longer than Paris green does and it usually sells at 
about two thirds the price of that poison. It seems to be going into 
disfavor because of its variable composition and the danger of its 
burning foliage. It is also considered somewhat less effectual in 
killing insects than is Paris green or Scheele’s green. It should 
compare favorably, however, with the prepared arsenite of lime in 
its power to kill insects, and there is little danger that it will be 
adulterated, as it is a waste product. 
Apply either wet or dry in the manner and in the same pro- 
pcrtions as are previously recommended for Pans green 5 being sure 
to add a pound or two of freshly slaked lime for each pound of 
poison if used as a spray. 
8 . BORDEAUX MIXTURE AND THE ARSENITES. 
Bordeaux mixture is a fungicide and is the substance most 
often used for the destruction of fungous diseases that attack 
the surface of the plants. It has been found to be of value for 
use against flea-beetles, and the writer also demonstrated its 
value a number of years ago as a medium in which to spray Paris 
green or London purple. These poisons can be used very strong 
in this mixture without injury to foliage and they do not in the 
least lessen its effect as a fungicide. Such a mixture will destroy 
both insects and fungi with one application. 
Bordeaux mixture may be prepared as follows: Take of 
Copper sulfate 
Quicklime .... 
Water. 
4 pounds. 
4 pounds. 
45 gallons. 
Dissolve the copper sulfate in a gallon of hot water, slake the 
lime in another gallon of water, and then add the milk of lime 
slowly to the copper sulfate solution while the latter is being con¬ 
stantly stirred. Then add 43 gallons of water. 
If insects are to be killed at the same time, add to the above 
quantity of Bordeaux mixture one-third pound of London purple, 
Paris green or Scheele’s green, or two pounds of arsenate of lead. ’ 
