334 SCHOOL ENTOMOLOGY 



to make 50 gallons. In making this mixture it is important 

 that only high-grade, pure lime should be used, and lime 

 with less than 90 per cent calcium oxid (CaO), should be dis- 

 carded. The following directions are given by the New York 

 Agricultural Experiment Station: 



"In making, slake the lime in about 10 gallons of hot 

 water, adding the lumps of lime gradually to avoid too violent 

 boiling and spilling over. . . . The sulphur must be thor- 

 oughly moistened and made into an even, fluid paste without 

 lumps (before adding to the lime). . . . Pour in the sulphur 

 paste gradually during the slaking, stirring constantly to 

 prevent the formation of lumps, and when the slaking has fin- 

 ished add the full amount of water and boil gently for one 

 hour. If kettles and fire are used, more than the required 

 amount of water may be used at first, to compensate for 

 evaporation, or the volume may be kept constant by adding 

 successive small quantities to hold the mixture at the original 

 level, as shown by a notch on a stick resting on the bottom 

 of the kettle, and marked when the mixture first begins to 

 boil. When boiling with live steam the mixture will be more 

 likely to increase in volume than to decrease, so that no 

 water need be added. 



"This concentrate will keep with little change, unless the 

 weather is below 5 F., if stored in filled, stoppered barrels. 

 Even in open receptacles there will be no loss if the surface be 

 covered by a layer of oil to prevent access of air. Each 

 boiling should be tested with a Baume* hydrometer * and 

 its density marked on the barrels or other containers." 



Below is given a table from which can be determined the 

 amount of dilution for concentrates for each degree Baume* 



* These hydrometers, made specially for testing lime-sulphur mix- 

 ture, may be obtained from the Bausch & Lomb Optical Co., Rochester, 

 N. Y., and other dealers in laboratory glassware. 



