REPORT OF THE CHEMIST 187 



SESSIONAL PAPER No. 16 



Xos. 6832 and G935 are the product of the Chemical Laboratories, Limited, 

 T I'onto. One sample (6832) was procured from the manufacturers, the other (6935) 

 was sent us by a purchaser. For materials of this character, the samples shpw a very 

 satisfactory uniformity, both as to total dissolved sulphur and as to that present as 

 sulphides. 



The directions are to dilute one volume of concentrated wash with eleven of 

 water. So diluted, the spray would contain the weights of sulphur (total and as sul- 

 phides), per 40 gallons, indicated in the sixth and seventh columns of the table. 



ISTos. 6933 and 6934, forwarded by the St. Catharines Cold Storage and Forward- 

 ing Company, St. Catharines, Ont., were accompanied by the following particulars : — 



' No. 3 (6933) 25 lbs. sulphur and 16 lbs. lime, boiled one hour.' 

 * No. 4 (6934) 22 lbs. sulphur and 16 lbs. lime, boiled one hour.' 

 ' For use, dilute with an equal volume of water.' 



These two washes are practically the same as to total sulphur-content, containing 

 about one-third of the sulphur in the samples just considered. The amount of sulphur 

 as sulphides is approximately one-fourth that in the other members of the series. As 

 sold, therefore, these washes are the weakest of the samples examined. Since, however, 

 in the preparation of the spray for use the directions are to dilute with an equal 

 volume of water — and not one to eleven, as for the other washes — the resultant sprays 

 are the strongest in the series. 



The proportion of sulphur present as compounds other than sulphides is very 

 much larger than in any of the other brands. These compounds are sulphates, sul- 

 phites and thio-sulphates, and are considered practically of no value from the horti- 

 cultural point of view. 



Nos. 6822, 6766 and 6936, are made by the Grasselli Chemical Company, Cleve- 

 land, Ohio, U.S.A., two of the samples being sent by the manufacturers, the third by 

 a purchaser. They are well prepared solutions, uniform as to composition and rich in 

 sulphides. 



The more generally used formula to-day for the home-made lime-sulphur solution 

 for dormant wood reads as follows: — 



Sulphur, powdered or as flowers 15 lbs. 



Lime 20 " 



Water 40 gallons. 



The directions for the preparation of the spray are: Slake the lime with hot 

 water, avoiding excess, and while slaking add the sulphur by dusting it over the lime 

 and stir well together. On the completion of the slaking add more water to facilitate 

 stirring and boil for an hour. Strain and dilute to 40 gallons.* 



If all the sulphur is dissolved, as it should be, the spray necessarily contains 15 

 lbs. of sulphur, practically all of which should be present as sulphides, per 40 gallons. 

 It is obvious, therefore, that such a spray will be somewhat stronger than the diluted 

 washes of the Chemical Laboratories, Limited, and the Grasselli Chemical Company, 

 and of about equal strength with those of the St. Catharines Cold Storage Company. 

 Hov/ever, sprays of any desired degree of concentration may be made from these com- 

 mercial preparations by a recognition of their sulphur-content and diluting accord- 

 ingly. The final cost of the spray ready for use (say, per barrel of 40 gallons) made 

 from any commercial lime-sulphur wash will depend upon the price of the wash 

 (including freight) and the degree to which it can be diluted to give a spray of a 

 desired strength. 



* In connection with the home-made spray, it may be pointed out that our experiments 

 show (1) that provided the lime is ^ood there is no necessity to iise more lime than sulphur 

 ill order that the latter may be all brought into solution, and (2) that as soon as all the 

 sulphur is brought into solution boiling should cease, as continued boiling tends to increase 

 the proportion of sulphur compounds of less value than the sulphides. 



