48 GOOSEBERRY. 
Various other communications were sent me, unnecessary to enter 
on at length, including information on the 21st of May of great 
numbers of Gooseberry Sawfly caterpillars being observed near Crocken 
Hill, Swanley, Kent; and on the same day it was reported from 
Billinghurst, Sussex, that they were “fearfully troubled by the Goose- 
berry caterpillar in that district.” 
Lonpon-PURPLE as an insecticide.—The following detailed notes of 
method of (and also success of) application of London-purple for getting 
rid of the Sawfly caterpillars are well worth attention, not only as a 
cheap and simple method of getting rid of this special pest, but also 
because, if properly used, it is as serviceable for use as an insecticide 
as the better known Paris-green. Both of the chemicals are poisonous. 
The Paris-green is an aceto-arsenite of copper, the London-purple is an 
arsenite of lime; both therefore require care in use, as has been 
specified before. 
The great difficulty in the first use of London-purple was that in 
the U.S.A. (from whence, as well as in the case of Paris-green, we first 
learnt its value) it was thrown out as a waste product of such various 
strength that nothing but special trial of extent to which it might need 
diluting made its use safe. Here, however, we can procure analysis 
which saves successive trials. I have at this minute that of Messrs. 
Hemineway, of Mark Lane, London, E.C., before me. 
The following note was sent me on May 10th by Mr. F. Nixon, 
from Great Eversden, near Cambridge :—‘‘ With regard to the Lon- 
don-purple, I have used it for the last five to six years, and at the 
outset made sad havoc amongst my trees and foliage, in fact I killed 
numbers of trees by giving too strong an application. Iam wiser now, 
and have found out the proper proportions in which to mix it. Nothing 
appears to me so good, cheap, or easy of application. JI use Heming- 
way's, and mix in the proportions of 1 lb. of purple to 200 gallons of 
water. The purple itself should be mixed to the consistency of paste 
before finally mixing with the bulk of water, and this bulk must be 
well stirred every time the spraying-machine is filled, otherwise the 
purple will be all at the bottom, and the water at the top, the effect of 
which is that in some places the caterpillars are not killed, and in 
others the foliage is scorched (I am speaking of Gooseberry-bushes). 
“Our No. 86 spraying-machine (the one I am interested in), 
manufactured by Messrs. Boulton & Paul, of Norwich, is an excellent 
implement for spraying this insecticide for the reasons that for this 
purpose I have a return-pipe attached to the pump, so that a strong 
jet of the mixture is continually forced through the bulk which the 
tank of machine contains, thus keeping the whole, as it were, boiling 
and well mixed up. 
«The caterpillars are not killed the same day the application is made. 
