1902 ENTOMOLOGICAL SOCIETY. 21 



When it becomes cold the lime and sulphur appear to crystallize and we have water and 

 crystals, but we cannot stir it up neither can we restore it to life by cooking, and it will not 

 stifik when we put it on the trees. The preparation must therefore be applied while hot. 



The Chairman : After it is in condition to apply to the trees, how long before it 

 crystallizes ? 



Mr. Fisher : As soon as it gets cold ; it would probably take half a day to cool. There 

 is no trouble in getting it on after it is prepared, if you are not interrupted. 



Mr. W. E. Saunders : As regards the chemical nature of this compound, it might be of 

 interest to state that when the lime and sulphur are combined together, they make sulphide 

 of calcium, and sulphide of calcium freshly made is soluble. It has been in use in the drug 

 business for a long time as a remedy for skin diseases, and I have found that iu the strength 

 which we make it, which results in a bright brick-red solution, it does not crystallize. I 

 should think thit the crystals occur from making the solution too dense We have a solution 

 in stock now, that has been made for perhaps three months or six months and it is still of a 

 deep orange-red color ; it contains sulphide of calcium and probably some sulphur. This 

 solution we have bottled up and it is in good condition to- day. When it is exposed to the air 

 it forms upon the surface a flake of a mixture of sulphur and sulphide of calcium. Decom- 

 position, no doubt, will go on to a more rapid extent as it is exposed longer to the air. I 

 should think that by putting this material in barrels, filling them right to the top, ^nd putting 

 the plug in the bung, it could be kept for weeks. If you have more sulphur than the solution 

 can take up, it might possibly take it up while hot and throw it down when cold. If it had an 

 excess of either one it might leave the residue in the bottom. 



Mr. Fisher : We have very little sediment ; the mixture appears to be perfect We did 

 have a lighter wash, but it left the sulphur exposed, so that it would be blown away by the 

 wind or washed off by the rain, whereas by using a pound of lime and half a pound of sulphur 

 to the gallon of wash, it left the sulphur covered. The sulphur seems to be deposited between 

 the lime and the bark of the tree. 



Prof. LocHHEAD : I had a talk with a chemist at the Pittsburg meeting and he stated that 

 when you b )il sulphur and lime together, you get various kinds of sulphide of calcium There 

 are sulphides of a high and a low degree, and these diflfer very remarkably. 



Prof. James : This is one of those things where the practice is of far greater value than 

 the theory. We all know that the various forms sulphur assumes depend entirely upon the 

 temperature to which it is heated. The use of the lime and sulphur mixture for the treatment 

 of the San Jose scale in the eastern part of California has presented a very interesting feature 

 to me. Perhaps most of you know that in the early days this favorite stand-by, or method, 

 used in California was used here, but we were told by the American Entomologists' that it was 

 not at all applicable ,to the eastern part of the continent. It is quite evident now that our 

 American friends came to a conclusion too raj) idly, bejause when Mr. Fisher's department 

 used that treatment he wrote to a large number of the Entomologists on the other side, and in 

 their replies they admitted that their previous conclusions were hardly correct. Mr. Fisher 

 has practically shown them the way in this matter, and I think we can safely say that his 

 experiments are in advance of anything that has been previously done in the Eastern States, 

 or the Eastern half of the Continent. The only way in which they can be said to have gone 

 beyond us is in the very important work done at the Department of Washington, in sending 

 to China and Japan for the natural parasites of the insect. It seems that after trying many 

 experiments, we have got out into the light and are now where we have some safe and sure 

 footing with regard to this insect. 



Dr. Fletcher : With regard Jto what Prof. Lochhead has said, that this work was shown 

 o be of great importance at the Pittsburg convention, the suggestion has been made that our 



