16 MASS. EXPERIMENT STATION BULLETIN 201. 



combined with the lime spUts off and fails to redissolve on the addition 

 of water, and is termed free sulfur. 



Compositio7i. — Dry lime-sulfur is usually guaranteed about as 

 follows: — 



Per Cent. 



Active ingredients, . . . . . . . . . .80.00 



Calcium polysulfide, 63.00 



Calcium thiosulfate, . . . . . . . 5.00 



Free sulfur 12.00 



Inert ingredients, . . . . . . . . . .20.00 



100.00 



A 33° Baume lime-sulfur solution containing 24.75 per cent sulfur, con- 

 centrated to a like basis, should contain substantially 61.95 per cent total 

 sulfur. If 12 per cent was rendered insoluble by evaporation, 49.95 per 

 cent remains soluble. Five per cent calcium thiosulfate is equivalent to 

 2.11 per cent thiosulfate sulfur, which deducted from the soluble sulfur 

 leaves 47.84 per cent polysulfide sulfur. 



(3) Barium Tetrasidfide. 

 Barium tetrasulfide (25) or B. T. S. was prepared experimentally as 

 an insecticide by the Thomsen Chemical Company of Baltimore, Md., in 

 1913. The product is guaranteed as follows: — 



Per Cent. 

 Ac Live ingredients, . . . . . . . . . . 82 . 00 



Barium tetrasulfide (BaSO, 68.00 



Barium thiosulfate, . . . . . . . 6.00 



Free sulfur 8.00 



Inert ingredients, . . . . . . . . . .18.00 



100.00 



Barium tetrasulfide is a fairly satisfactory contact poison, yet it pos- 

 sesses no distinct advantages over lime-sulfur preparations. It has never 

 replaced lime-suKur to any great extent, and is not now widely used, 

 largely because it is more expensive. 



(4) Soluble Sulfur. 

 Soluble sulfur or sodium polysulfide was first marketed by the Niagara 

 Sprayer Company of Middleport, N. Y., about 1912. Con-sol, a sodium 

 sulfur compound, prepared by the American Horticultural Distributing 

 Company of Martinsburg, W. Va., was offered about 1905, but little in- 

 formation has been received relative to the nature of the product. 



