16 



MASS. EXPERIMENT STATION BULLETIN 201. 



combined with the Hme sphts off and fails to redissolve on the addition 

 of water, and is termed free sulfur. 



Composition. — Dry hme-sulfur is usually guaranteed about as 

 follows : — 



Per Cent. 



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



Calcium polysulfide 6.3 . 00 



Calcium thiosulf ate, . . . . . . 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 substantial!}' 61. 9o per cent total 

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

 cent remains soluble. Five per cent calcium thiosulf ate is equivalent to 

 2.11 per cent thiosulf ate sulfur, which deducted from the soluble sulfur 

 leaves 47.84 per cent polysulfide sulfur. 



(3) Barman Tetrasulfide. 

 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. 

 Active 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 Hme-sulfur to any great extent, and is not now widely used, 

 largeh' because it is more expensive. 



(4) Soluble Sulfur. 



Soluble sulfur or sodium polysulfide was first marketed by the Niagara 

 Sprayer Company of INIiddlcport, 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. 



