276 Fungicidal Properties of Certain Spray-Fluids 



23 grams of calcium chloride (prepared from twice reprecipitated calcium 

 carbonate) in a small volume of water. A white flocculent precipitate 

 formed which quickly became powdery. Thi.s was filtered on a Buchner 

 funnel, thoroughly wa.shed with cold water and whilst still wet was trans- 

 ferred to a beaker with 250 c.cm. of water and stirred mechanically for 

 an hour. The solid was then allowed to settle and the supernatant liquid 

 filtered. For spraying 90 c.cm. of this solution were mi.xed with 10 c.cm. 

 of calcium caseinate solution (10 per cent.). 



Experiment 36. Calcium sulphite (saturated solution) and 1 per cent, 

 calcium caseinate. Exactly the same result was obtained as in E.xperi- 

 ment 32, described above. 



A saturated solution of calcium sulphite having proved to be non- 

 fungicidal, a suspen.sion of the solid sulphite was adjusted (by means of 

 titration with standard iodine solution) to contain 5 grams in 90 c.cm. 

 of liquid and this 90 c.cm. treated with 10 c.cm. of 10 per cent, calcium 

 caseinate solution for .spraying. 



Experiment 40. Calcium sulphite (su.spension), 5 per cent., and 1 per 

 cent, calcium caseinate. Exactly the same result was obtained as in 

 E.xperiment 32, described above. 



Calcium thiosulphale. The preparation of a small quantity of the pure 

 salt is rendered difficult by its high solubility in water, and an attempt 

 to obtain it by double decomposition of calcium chloride with sodium 

 thiosulphate failed through the inferior solubility of sodium chloride. 

 By stirring a mixture of 27 grams of pure barium thiosulphate 

 (BaSgOj.HgO) and 16 grams of pure calcium sulphate (CaS04) in 250 

 c.cm. of water for 10 hours and then filtering, a solution was obtained 

 which gave a reaction for sulphate but not for barium and on titration 

 with standard iodine solution proved to contain 1-321 grams of thio- 

 sulphate sulphur per 100 c.cm. This solution contained only calcium 

 thiosulphate and calcium sulphate and the latter had been proved non- 

 fungicidal. Ordinary commercial lime-sulphur solution contains roughly 

 1-5 per cent, of thiosulphate sulphur per 100 c.cm.. so that the wash 

 obtained by diluting with 29 parts of water contains 0-05 per cent, of 

 thiosulphate sulphur. A spray solution containing the same amount of 

 sulphur (as calcium thiosulphate) was prepared by diluting 3-78 c.cm. 

 of this calcium thiosulphate .solution with water, adding 10 c.cm. of 

 10 per cent, calcium caseinate solution and making up to 100 c.cm. This 

 was applied (Experiment 38) and proved to be quite non-fuugicidal. 



A solution ten times as strong was prepared by adding 10 c.cm. of 

 calcium caseinate solution (lO per cent.) to 37-85 c.cm. of the calcium 



