399 



Before use as a spray on the foliage of plants the concentrated 

 wash obtained as above requires to be diluted. The amount of di- 

 lution which is necessary in order to avoid " scorching," varies 

 with the character of the foliage or plant to be sprayed, and can 

 only be ascertained by experiment. In the experiments described 

 above, a lime-sulphur wash having a specific gravity of i.oi was 

 used; this is obtained by adding from about 20 to 23 gallons of 

 water to every gallon of the concentrated wash according to the 

 specific gravity of the latter, which will vary slightly. When di- 

 luted, the wash must be used at once. Hydrometers with a spe- 

 cially prepared scale and directions for use can be obtained, price 

 3*. 6</. each ; by means of one of these instruments the specific 

 gravity of the concentrated or diluted wash can instantly be as- 

 certained. Under the conditions in the experiments described above 

 a lime-sulphur wash of the specific gravity i.oi produced no "scorch- 

 ing" on the leaves of the hop, gooseberry, or apple. On the young, 

 tender foliage of roses in the Greenhouse, "scorching" resulted 

 with a wash of this strength; in such cases the wash should be 

 used at half strength. It is possible that under certain weather 

 conditions this weaker strength will be necessary for the hop, 

 gooseberry, and apple also in order to avoid "scorching" the fo- 

 liage. In all cases the lime-sulphur wash should be first used on 

 an experimental scale, the specific gravity of the diluted wash (or 

 the number of gallons of water added to each gallon of the con- 

 centrated wash) being carefully noted. A few plants should be 

 sprayed with a wash having the specific gravity i.oi; and then, if 

 necessary, further dilution with water should be made. 



In the boiling together of the lime and sulphur a chemical re- 

 gion takes place, bringing about the solution of the lime and 

 sulphur. The best proportions of lime and sulphur to use are be- 

 lieved to be those given above. 



After application to the leaves, the wash is acted upon at once 

 by the atmosphere, with the result that sulphur is almost instan- 

 taneously deposited. The sulphur thus deposited is in an excess- 

 ively fine state of division - the particles being many hundred 

 times finer than those of "flowers of sulphur" and in conse- 

 quence adheres, in the form of a whitish powder, so intimately to 

 the surface of the leaf that rain will not wash it off. If sprayed 

 leaves, when once the spray is dry, are placed under running water 

 from a tap, it will be found that the whitish powder consisting of 

 sulphur is not washed off. 



