78 



that the stuff should be ground up in the mortar and make it all the more liable to 

 dissolve. If this is not done it gets hard and insoluble. The London purple is more 

 soluble than Paris green. 



Mr. Hamilton. — I think there is some misunderstanding as to what spraying 

 really is. I saw some people spraying in the gardens among potatoes, and they 

 literally deluged the plants. Under such circumstances there is little reason that the 

 spraying does not work effectually. 1 was doing a portion of ray garden with Paris 

 ereen, and came near the end of my Paris gi-een, it was running out, and 

 I put in a less quantity of Paris green, and the work was done more 

 effectually than with the larger quantities. I think if the spraying is done 

 in such a way as it will best fall on and not run off, that a very small 

 quantity of Paris green is iiecessary. With regard to the use of sulphur on grapes, 

 about thirty years ago I had a large vinery, and to destroy Thrip I used to close 

 up the house at 4 p.m., moisten the ground all over and start a tire in the house, and 

 with a little sulphur burned I filled the house with sulphur fumes, and there was not 

 a sign of Thrip. The result is, I never had any trouble with Thrip. 



Prof. Shutt. — I fear members of the Convention might go away with the im- 

 pression that while London purple is not definite in strength that Paris green can 

 always be depended on. This is not the case. Very often commercial samples of 

 Paris green contain as much as 25 per cent, of gypsum, which, of course, has no 

 value as an insecticide. 



Mr. Fletcher.- — ^The statement made was that the amount of arsenic in Paris 

 green was much more definite than in London purple. I believe Paris green 

 contains about 60 per cent, of arsenical material. It does not matter what the other 

 40 per cent, is made up of. But what I wish to state is merely that Paris green is 

 much more definite in its strength than London purple, that it is a good remedy, and 

 that it will pay fruit-growers to use it. I had a series of analyses made some year 

 or two ago by the Department of Inland Eevenue, and the percentage of adulter- 

 ation varied from 1 to 10 per cent, in Paris green ; and in the London purple, on the 

 other hand, the amount of arsenic varied from 60 to 18 per cent, in the series of 

 experiments that were made. Of course, I do not recommend the London Purple at 

 all because of the uncertainty about it ; but good results have been obtained by it. 

 All I said was, if you want to get the pure article and know what you are usiijg buy 

 Paris green; although a little tigher in price than London Purple, it is more 

 reliable. 



Prof. Shutt.— I have no doubt we very often get the pure article. What I want 

 to point out is, that we do not always geflOO per cent, of Paris Green, and the con- 

 sequence is that the strength as an insecticide is lessened. 



Prof. Shutt then read his paper on the "Composition of Apple Tree Leaves." 



THE COMPOSITION OF APPLE TEEE LEAVES. 



Agricultural chemists throughout the world are, and have been now for some 

 years, directing their attention towards the solution of questions concerning the 

 growth and bringing to perfection of plants and animals which serve for the use of 

 man. With regard to plants — and by that term I include all farm crops — analyses 

 have been made of all their parts, so that their composition is, to-day, pretty well 

 known. 



Field experiments and experiments in water culture — in which the various 

 salts required by the plants are dissolved in water — have also been made, enabling us, 

 at the present time, to state definitely what special fertilizing constituents are valu- 

 able for the growth of certain crops, what classes of soil are most suited to cereals, 

 the leguminous plants, and so on. 



But as yet it appears that little has been done in this direction for the fruit- 

 growers, and the reason for this is not difficult to find. In all experiments of this 

 nature it is necessary to weigh and analyse an aliquot part of the final product of 

 vegetable growth in order to arrive at the amount of plant food absorbed from the 



