320 



ON THE CULTURE 



as not to be found on the most diligent search, 

 and the difficulty has always been to destroy these 

 insects in that situation. 



The getting oil to incorporate effectually with 

 water seemed an insurmountable difficulty ; and 

 it was no less difficult to preserve a sufficient effi- 

 cacy in the spirits, as it was necessary to lower 

 them (or let them down as it is termed) with water, 

 lest the plants should be injured. From these 

 considerations it is manifest, that neither of these 

 discoveries will answer the intended purpose. 



I observed that the meal, or down, described on 

 the last species of insects (which meal, or down, I 

 presume, like the feathers of water-fowl, greatly 

 abounds with oil) prevented the decoctions from 

 getting to the insects, even after a steeping of 

 twenty-four hours : from thence I was led to ima- 

 gine that something of a very penetrating nature 

 was requisite to destroy them. After many ex- 

 periments, and due consideration of the nature of 

 these insects, I luckily happened to think of a 

 remedy which hitherto has proved effectual c ; and 

 I submit it to the public with the most exact pre- 

 cision. 



I first tried it on a few Pine-plants, and after- 

 wards upon the whole stock, and in both cases 

 with the greatest success, not one of these de- 



« Since the first publication of this work, I have received, 

 from the most respectable authority, numerous and satisfactory 

 accounts respecting the efficacy of the method here recom- 

 mended. 



