io8 Vbe Principles of Part III. 



time to have deftroyed the plants like a 

 poifon. This fubftance is often fprinkled 

 on turnip-feed before it is fowed; and it 

 is thought by farmers to amft their growth, 

 and to keep the flies from the leaves. Was 

 too great a quantity of it-ufed in this ex- 

 periment ? Plants, therefore, have not only 

 their food, but their poifon. Quter. Will 

 the artificial fulphur, which arifes from the 

 combuftion of many plants in a particular 

 way, and which is to be found in great 

 plenty in kelp-afhes, in the foap-ames, and 

 in many of the afhes ufed in the bleach- 

 field, have the fame bad effects as natural 

 fulphur ? 



AFTER the laft experiment was made, 

 there appeared to me a confiderable diffe- 

 rence betwixt the method by which it was 

 carried on, and the courfe which nature 

 follows in fuch operations. I mixed the 

 materials, whofe effects on vegetation I 

 wanted to difcover, all at once with the 

 earth: but in a natural way, the fructifying 



prin- 



