224 ENTOMOLOGICAL NEWS. [Sept., '02 



close of the season the trees would be quite free from scale. 

 The following questions naturally suggested themselves : 



1. Is the effectiveness of the wash due to the percentage of 

 the scales killed at the time of treatment ? 



2. Does the coating on the trees prevent the successful attach- 

 ment of the young scales ? 



3. If it prevents the attachment of the young scales is the 

 entire combination necessary ? 



In order to get definite information on the points in question, 

 the following tests were made by me, under Mr. Lounsbury's 

 direction, at the Government wine farm, Constantia. 



1. Lime-sulphur-salt wash, using 40 pounds of lime. 



2. Lime-sulphur-salt wash, using 20 pounds of lime. 



3. Lime-salt wash. 



4. Lime wash. 



5. Lime-sulphur sheep dip ; i part dip to 5 parts water. 



6. Lime-sulphur sheep dip ; i part dip to 10 parts water. 

 The washes of the first four tests were prepared on the basis 



of the following formula : Unslaked lime, 40 punds ; sulphur, 

 20 pounds; stock salt, 15 pounds; water to make 50 imperial 

 gallons. Ten pounds of lime and 20 pounds of sulphur were 

 placed in the cooking kettle with 15 imperial gallons of water 

 boiled until the sulphur was all dissolved. In tests i and 2 

 the remaining lime was slaked, the salt added, and while hot 

 the two mixed with the lime-sulphur solution and the whole 

 boiled for 30 minutes. No analysis was made of this batch of 

 washes, but the lime-sulphur solution of another prepared in 

 exactly the same way and with the same quality of lime, proved 

 to contain lime and sulphur in solution in the ratio of i : i.Si. 

 (by volume) ; another batch made with poorer, long slaked lime, 

 contained a higher proportion of sulphur, namely, i : 2.07. It 

 was noticed that, without exception, the proportion of sulphur 

 was decreased by the addition of the extra lime, and that the 

 half hour's hard boiling did not restore the apparent loss : the 

 ratio generally becoming about: : 1.60. In tests 3 and 4, lime 

 and salt, and lime alone, respectively, were used in the propor- 

 tion to water given in the formula for the- complete wash. The 

 sheep dip is a concentrated solution of combined lime and sul- 



