THE VARIOUS FORMS OF SULPHUR 195 



sulfur content. The great advantage of this form is tliat it can 

 be made up on the farm during the winter when work is slack 

 and when the labor expense is relatively small. The general 

 method of preparation is as follows, though formulas and methods 

 are still undergoing changes : 



Formula. — 50 pounds rock lime, 100 pounds sulfur, 50 gallons water. 



It seems to be immaterial whether the sulfur is the flour 

 (finely ground) or the flowers, but the lime should be good and 

 should preferably have little magnesium in it. Slack the lime in 

 the kettle in which the cooking is to be done and when the slacking 

 is well started add the sulfur and mix thoroughly. Then add 

 enough water to make a thin paste. Continue boiling vigorously 

 until the sulfur is all dissolved, which will usually take from 

 forty-five minutes to one hour. When the boiling is finished the 

 concentrate may be put into barrels and stored. If these barrels 

 are perfectly tight and are filled full, no other precaution is neces- 

 sary than to cork up tightly. If these conditions do not obtain 

 then the concentrate must be covered with oil. Any oil which 

 will not injure the trees and which does not take fire at the 

 boiling point of water will do, and the various miscible oils are 

 used with entire satisfaction. There is sometimes considerable 

 sediment, but this does not seem to be a serious objection. 



The proper degree of dilution either with the home-made or 

 the commercial, as measured by the specific gravity scale on the 

 hydrometer, seems to be about as follows: For San Jose scale, 

 blister mite, peach leaf curl and other spraying when trees are 

 in dormant condition, 1.03. For apple and pear scab and similar 

 diseases, summer spray, 1.01. For peach scab and brown rot, 

 summer spra^', 1.005. It is probably better not to use this material 

 at all in spraying the stone fruits, especially peaches and Japanese 

 plums as while it will often do no harm, it will, on the other 

 hand, sometimes do serious injury to the leaves. 



3. The '' self-hoiled " lime-sulfur is that in which the heat 

 of the slacking lime is relied upon to cook the mixture. It is a 

 very mild form, being little more than a mechanical mixture of 

 sulfur and slacked lime, and is useful only as a summer fungicide. 



