EXERCISE XL 



THE STUDY OF LIME-SULPHUR 



Material. Stone lime, flowers of sulphur, commercial lime- 

 sulphur. 



Apparatus. One-gallon granite kettle, hydrometer, large glass 

 cylinders, cooking burner. 



It has been learned that lime-sulphur can be used as a fungi- 

 cide and in some cases is superior to Bordeaux mixture for 

 the spraying of certain plants and the con- 

 trolling of certain diseases. The point of 

 difference between lime-sulphur as a fungi- 

 cide and as an insecticide is the degree of 

 dilution, or the strength of the solution. The 

 strength can best be determined by the use 

 of a hydrometer (Fig. 37), which tests the 

 density of the solution. 



There are several formulas from which the 

 lime-sulphur is made. A good commercial 

 formula to follow is 



Stone lime 40 Ib. 



Flowers of sulphur 80 Ib. 



Water 50 gal. 



Laboratory formula. Weigh out four ounces 

 of stone lime and eight ounces of flowers of 

 sulphur. Place the lime in the granite vessel 

 and slake with water, adding the water gradu- 

 ally and being careful not to smother the lime 

 with too much water. Stir until the lime is 

 thoroughly slaked and forms a uniform paste. 

 Now add enough water to make a half gallon, 

 after which place over the fire and boil. Now mix the flowers of 

 sulphur to a thin paste, and add gradually to the lime when 

 boiling, and stir constantly. Allow the mixture to boil for about 

 an hour, stirring at frequent intervals. Keep the water in the 



[138] 



FIG. 37. Cylinder, 

 showing hydrometer 

 for testing the den- 

 sity of lime-sulphur 

 solution 



