550 ANNUAL RErORT OF THE Off. Doc. 



day of last December he reported to me that the results of this work 

 last spring were highly successful and eminently satisfactory. 



MR. HALE. — That is true. The chief feature of failure is a lack 

 of thorough application or failing to cover the trees entirely. 



A Member. — Does it make any difference what kind of sulphur 

 is used? 



PROF. SURFACE.— We shall come to that in a minute as it is 

 mentioned further on in this bulletin. It is all right to ask those 

 questions but the author says here something about the sulphur 

 which we shall soon discuss. "The lime used in preparing lime- 

 sulphur wash should be calcium lime instead of a magnesia lime." 



You who have not read my November and December bulletins will 

 consider this a new point but it was there discussed and I there said 

 it should be calcium lime instead of magnesia. 1 think the reason 

 for this, is that the calcium is much stronger or more caustic while 

 the magnesia is a nice mild white lime which when combined with 

 sulphur makes a mixture of different color but not so strong in its 

 killing effects on the scale. In boiling the wash, the operator can 

 know whether he has calcium or magnesia from the color it assumes 

 when cooked nearly an hour. The calcium mixture becomes t\fe 

 color of tomato catsup or boiled tomatoes, and cannot be cooked to 

 the point of changing on to a dark olive green color. While mag- 

 nesia lime mav become first the color of cooked tomatoes but will 

 later change to a dark or dirty olive green color, although it does not 

 always pass through the red or tomato color stage. 



A Member.-— Where will we get the best quality of lime in Penn- 

 sylvania for spraying purposes? 



PROF. SURFACE.— I find that the York lime is a good calcium 

 lime, while much of the Chester county lime is magnesia. 



I believe the next important problem my office should take up is a 

 study of the limes of Pennsylvania in relation to this point and 

 their efficiency in making good material that will kill the scale. 

 Many of the limestones of this State contain both calcium and mag- 

 nesia and consequently we may get the red color before the olive 

 green, or we may get a combination or mixture of the two. This 

 is a question pretty well discussed in a West Virginia bulletin and 

 any person can get it free by writing for it to Morgantown, West 

 Virginia. 



A gentleman from New Jersey. — We get a coffee colored mixture 

 when we boil lime. I have been brought up on that quality of 

 lime. Am I to understand that we are wrong? 



PROF. SURFACE. — The coffee colored mixture would not be so 

 bad as it indicates a mixture of both lime and calcium in the lime- 

 stone with doubtless enough calcium to bring good results. ^'Sul- 

 phur may be purchased in different forms bu t the grades most highly 

 recommended are 'flour' or 'flowers' of sulphur." The flower of 

 sulphur is gi'ound sulphur from cakes which have been melted and 

 allowed to cool and thus harden.' It is not as finely divided as that 

 form called the "flowers" of sulphur which is prepared by sublima- 

 tion or heating the sulphur and driving the fumes against the walls 

 of the room where it collects by settling the same as soot or lamp 



