Materials and Formulas. 169 



Simple solution of resin : 



Resin 2 pounds. 



Crystallized sal-soda 1 pound. 



Water 2 quarts. 



Boil the above until a clear brown solution is obtained. This 

 is an excellent method of obtaining a stock solution of resin. 

 It is as valuable as any soap to increase adhesive properties of 

 Bordeaux mixture, and costs much less. 



Resin 30 pounds. 



Caustic soda (70 per cent) 9 " 



Fish-oil 4 pints. 



Water 100 gallons. 



Place the first three ingredients in an iron kettle and cover 

 with five or six inches of water. Boil for an hour or two, or 

 until the liquid has a dark brown color, after which the re- 

 mainder of the water may be slowly added. It is not necessary 

 that all should be immediately used, since the liquid may be 

 diluted as well later. For winter use. 



RESIN WASHES AND ARSENICALS. Paris green, London 

 purple, and even arsenious acid will mix readily with resin 

 compounds, especially those which consist of resin, caustic soda, 

 and water. The poison may then be used at the same rate as 

 in clear water. Arsenious acid has been used in this manner 

 upon orange trees at the rate of 1 pound to 300 gallons of the 

 wash. 



SALT; SODIUM CHLORIDE; NACL. Common salt has very 

 frequently been recommended as an insecticide, and there is 

 no doubt that it is capable of killing many insects. But its 

 effective use requires such strong solutions that the remedy is 

 generally worse than the disease, and for this reason it is rarely 

 applied. 



SCHEELE'S GREEN. See ARSENITE OF COPPER, page 120. 



SCHWEINFURTH'S GREEN. See Paris Green, page 121. 



SKAWINSKI'S IRON SULPHATE AND SULPHURIC ACID SOLU- 

 TION. 



Iron sulphate 110 pounds. 



Sulphuric acid (53) 1 pints. 



Warm water , . . ? . , 26 gallons. 



