176 The Spraying of Plants. 



Sulphur generally sells for about three cents a pound whole- 

 sale, and ten cents retail. 

 SULPHUR AND LIME POWDER. 



Flowers of sulphur 1 part, 



Air-slaked lime 1 " 



Mix and apply in form of a powder. The mixture is of value 

 for surface mildews, but is little used in America. The Euro- 

 pean grape mildew is easily controlled by it. 



SULPHUR AND SNUFF. 



Flowers of sulphur 1 pound. 



Scotch snuff 1 " 



Quicklime 1 " 



Soft soap 1 " 



Lampblack i " 



Water, enough to make a thin paint. 



This formula contains an excellent variety of materials, but 

 other and simpler ones are undoubtedly equally effective in the 

 destruction of plant lice, for which the above is particularly 

 recommended. It should be used only upon dormant wood. 



SULPHUR AND WHALE-OIL SOAP WASH. 



Sulphur $ pound. 



Boiling water gallon. 



Boil the sulphur for fifteen minutes. To this add 



Whale-oil soap 1 pound, 



and boil for five minutes. Allow the mixture to stand a week, 

 and before using, dissolve 1 pound in a gallon of hot water, 

 making the application when the temperature has fallen to 

 130. It is supposed to be a repellent of various burrowing 

 larvae, as the currant borer, and others. 



SULPHURET OF POTASSIUM. See POTASSIUM SULPHIDE. 



SULPHURIC ACID. See IRON SULPHATE. 



TOBACCO ; NICOTIANA TABACUM. The active principle 

 of tobacco is nicotine, and this compound gives the plant its 

 value as an insecticide. It kills by coming in contact with the 

 insects, and so long as this occurs, the method of its application 

 is of minor importance. It is most commonly used for the 



