June 2, 1890.] THE TROPICAL JK9trcm.T0lt1&T,' 
825 
CATEEPILLAES AND ERUIT TEEES. 
It is satisfactory to those who, like ourselves, have 
for many years past devoted attention to the subject 
of insect depredators, and to the means of dealing 
with them, to find at last that public attention is 
being aroused to the importance of the matter. At a 
meeting recently held at Evesham, the Mayor in the 
chair, the subject was discussed at some length. The 
ways and customs of the caterpillars were described in 
a letter from Miss Ormorod, as well as the various 
remedies proposed. Greased bands applied in October 
are very effectual, but injure the young trees. This 
injury is avoided by smearing the grease upon paper, 
or, as Mr. Wilson suggested at the Scientific Committee, 
on canvas, and not directly on the bark itself. 
Kerosene emulsions in the proportion of one pint of 
kerosene, half an ounce of soap, and four pints of 
water, to be used in the form of spr.iy, were also recom- 
mended. But the most promising method is that 
which has been tried for many ytars in the United 
States and in Canada, and which, relying on the 
reports of suoh men as Professor Riley and Mr. Fletcher, 
we have earnestly pressed on the attention of our 
fruit growers for years past, but hitherto without avail. 
Either from our national slowness in adopting new 
processes, or from a fear of injury from the 
arsenical preparations, little or no progress has been 
made in this country with these valuable remedies ; 
and yet the proportion used is so small that the risk 
to human life is too small to deter any person of or- 
dinarily careful habits from making use of them. 
Spraying with an arsenical solution should be done 
in the middle of April, when no fear need be entertained 
from the falling of the arsenic on to bush fruits 
grown under the Apples, though in the case of vege- 
tables the case is somewhat different. The propor- 
tion of Paris green recommended is 4 oz. to 40 or 50 
gallons of water (four ounces to forty or fifty 
gallons). In the 40 gallons there would be about 1 
oz. of arsenic, and this would be distributed by the 
spray pump over, say, an acre of leaf surface. The 
danger, therefore, is clearly not in the proper 
use of the arsenic, but in the careless handling of 
the poison by ignorant or stupid people, a contingency 
which has always to be provided for. 
We extract from the Evesham Journal the following 
letter, showing more explicitly how these arsenical 
preparations are used: — 
" To every 50 gallons of water, mix well, and keep 
well stirred while using 4 oz. of Paris green. For 
Plums, as they are tender, and as the leaf is glossy, 
add three tablespoonf uls of fine flour from Wheat to 
make it stick on the leaves. Get a pan or dish, and 
make a paste of either or both, with a little water, 
as it mixes better with a bulk of water, and test it. 
If too weak, use 4 oz. to 40 gallons. If the Paris is 
a pure article, this will be found enough. Use 4 oz. 
to 40 gallons of water for Apple and Pear trees. 
Cherries may be treated the same way. Two dressings 
will, as a rule, be sufficient — 1st, when the blossoms 
are falling and fruit beginning to form ; 2nd, in twelve 
to fourteen days. Use your best judgment on this by 
observation. As soon as blossoms have fallen off, and 
while fruit is nearly upright, get a force-pump fixed, 
good, short, and handy, and in a barrel on wheelbarrow 
or wheels that can be moved handy to any place. 
Have a rubber hose of 1 inch by 8 feet long, or longer 
for tall trees ; fix this on a handy pole, so that a man 
may shower ordinary trees without a ladder, and shower 
trees where insects are, much the same as a fine 
watering-pot rose would shower. Test your pump 
beforehand with clear water to get it to work satis- 
factorily- A large garden syringe may be used, but 
would take too long. A fine shower is what is want- 
ed. You want two roses or nozzles, one for short and 
one for long distance. The ordinary pail of water is 
enough for a large-sized Apple tree. If heavy rain 
should follow as soon as the poisoned water is showered 
on trees, you will have to shower again. I have never 
known fruit to be hurt or any harm done by this, if 
used properly. The quantity is so small, and the 
time so long before fruit ripens, that every trace is 
lost. In an orchard where there are cattle, sheep, &c, 
it would not be wise to let them graze for a few days 
after showering the trees with poison. If left for hay, 
this will not hurt the hay. 
"As to the time for showering, I propose the 
morning, when the leaves are dry, or any time when dry, 
as the sun absorbs the water, and mineral poison settles. 
If the water is not sunned to near the same heat as 
the surroudingn atmosphere, make a small fire and heat 
a few brioks before using, and temper the water in a 
tub, use a thermometer, and heat water to same degree 
as atmosphere. This is very important. 
" Paris green is an arsenical poison. To shower 
when in bloom may do harm, and destroy bees. Loudon 
purple, or arsenite of lime, is about equal to Paris 
green, and used the same way. Both are poisons, and 
should be used carefully. I recommend those that use 
one to use the other, and test them on separate rows of 
trees. Paris green or London purple costs here Is. to Is. 
3d. per pound. This is the cheapest and most effectual 
way to destroy these pests by actual tests. As the 
young grubs eat a small part of leaf or fruit, a very 
small particle of this posion will kill, and save a great 
percentage of the fruit ciop. I have used Paris green 
eight years, London purple two years, on fruit and 
vegetable." — Enoch Haines in Evesham Journal, — 
Gardeners' Chronicle. 
+ _ 
LONDON PURPLE. 
If we suggest that dealers should advertise their 
wares, we shall at once be considered to have in- 
terested motives — well, we have — the following narra- 
tive will show why. Our American friends make 
large use of various preparations of arsenic and other 
substances for spraying purposes, either for the attacks 
of insects or of fungi on various crops. We have re- 
peatedly mentioned the fact, and urged our orchardists 
to adopt the methods employed with so much success 
in the States. Among other things, we have detailed 
the use of " .London Purple." Some of our correspon- 
dents, attracted by our frequent reference to the 
subject, at length wrote to inquire what was " London 
Purple," and where it could be had? We knew or 
surmised it to be an arsenical preparation, and made 
sure that we should find referenoe to it in the autho- 
rised dictionaries of chemistry and pharmacy. But 
no ! not one word could we find about the substance 
though it was evidently used on a very large scale. 
Finding books useless, we appealed to our chemical 
friends, to scientific chemists of high repute, to manu- 
facturing chemists, to pharmacists, but all to no avail, 
till at length Mr. Holmes, of the Pharmaceutical 
Society, was good enough to put us on the right 
track. But in the meanwhile, finding that in London 
we could get no information as to " London Purple," 
we bethought ourselves that there was a London in 
Canada ; and still later we bethought ourselves of our 
excellent correspondent Prof. Riley, the Director of 
the United States Entomolygical Department, and he, 
with his customary kindness, gave us the information 
we wanted, adding that Hemingway & Co., of London, 
aniline dye manufacturers, have given the name in 
contradistinction to Paris Green, and have established 
a branob house in New York, the sale of this valuable 
insecticide being, it is believed, one of their most im- 
portant transactions. Two reflections occur to us on 
this story, one is that manufacturers should advertise 
(in the Gardeners' Chronicle, of course — anywhere else 
they like), the other is, that this is one more illus- 
tration of the abominable time-wasting, trouble-giving, 
truth-concealing nature of "popular names"! 
This powder is obtained in the following man- 
ner in the manufacture of aniline dyes : Crude coal- 
oil is distilled to produce benzole. This is mixed with 
nitric acid, and forms nitro-benzole. Iron filings are 
then used to produce nascent hydrogen with the excess 
of nitric acid in the benzole. When distilled, aniline 
results ; to this are added arsenic acid, to give an 
atom of oxygen which produces rose aniline, and quick- 
lime to absorb the arsenic. The residuum, which is- 
obtained by filtration or settling, ia what has been 
denominated "London purple," the sediment being. 
