San Jose Scale. 269 



Third.- — By adding five pounds of lime to the preceding formula, all the sul- 

 phur was used, and a more perfect combination obtained. This formula, twenty- 

 five pounds of lime, twenty pounds of sulphur, and fifteen pounds of salt to fifty 

 gallons of water, was used on the greater part of the orchard. Prom the 

 amount of sulphur left undissolved when equal quantities of sulphur and lime 

 were used, it is evident that more lime than sulphur should be used, what- 

 ever the formula may be. 



TIME OP COOKING. 



The chief objection to the use of sulphur, lime, and salt has been the expense 

 of cooking. The first formulas used in the West called for four hours' time 

 in cooking. Later investigations have shown this length of time to be unneces- 

 sary. In the work here described the time taken at first was one hour before 

 the salt was added and fifteen minutes afterward. Experience soon showed, 

 however, that after the materials were boiled from thirty to forty-five minutes, 

 the sulphur was all dissolved, after which time no beneficial change took place. 

 No difference could be detected in the time required for cooking or in the nature 

 of the solution, whether the lime was slaked and the sulphur added afterward or 

 all three ingredients were put together in the barrel, water added, and steam 

 turned on. 



Still later investigations have shown a more economical way of boiling 

 the mixture. Lime in slaking generates a large amount of heat. If the lime 

 and sulphur are put together in the cooking tank, and hot water is added to 

 slake the lime, the heat generated goes a long way toward dissolving the mixture. 

 An old blanket thrown over the barrel helps to hold the heat in. Long continued 

 boiling causes the solution to form a thick, black precipitate, that sometimes 

 gives trouble by clogging the strainer and nozzles. 



EPPECT OP SOLUTION ON MEN. 



Sulphur and lime solution has had a reputation of producing a bad effect 

 on the operators using it. To avoid this trouble the men were provided with 

 oilskin jackets, trousers, and hats, and rubber gloves. Even with these pre- 

 cautions more or less of the solution came in contact with the hands and faces 

 of the men ; but in no case did any injury result. The material is disagreeable 

 and is ruinous to clothes, especially leather, so the use of oilskins and rubber 

 is advisable. 



RECORD OF WORK. 



One of the principal objects in taking on this work was to determine the 

 effect of the sulphur, lime, and salt solution on the scale and trees when applied 

 under different weather conditions. The work of applying the mixture extended 

 over a period from March 10th to April 14th. During this time several heavy 

 rains occurred, some of them following very closely the application of tne solu- 

 tion. These rains did no apparent damage to the solution that had become dry 

 on the trees. It was found not to be advisable to apply the solution when the 

 trees were wet, as it would not stick sauisfactorily. 



THE OREGON PORMULA. 



In Oregon, copper sulphate has been used in addition to the sulphur, lime. 

 and salt for the purpose of making it a fungicide as well as an insecticide, 

 hence the sulphur, lime, and salt, plus the copper sulphate, is known as the 

 Oregon solution, or Oregon formula. In preparing this formula the same 

 amounts of materials were used as before (twenty-five pounds of lime, twenty 

 pounds of sulphur, and fifteen pounds of salt), with four pounds of copper sul- 

 phate added. When the copper sulphate was added in a concentrated solution 

 to the other ingredients, a heavy black precipitate like coffee grounds was 

 formed, which caused trouble in straining. A more dilute solution of the sul- 



