CH. YIII.] THE DISEASES OF PLANTS. 269 



this in his poTver ^ith but little difficulty, for he can 

 keep the ^-icinity of his cabbage, cauliflower, and 

 brocoli plants soaked with water. 



Mr. Smith, gardener to M. Bell, Esq., of Wool- 

 sington, in Northumberland, expresses his conviction 

 after several years' experience, that charcoal-dust, 

 spread about half an inch deep upon the suiiace, and 

 just mixed with it by the point of a spade, effectually 

 prevents the occurrence of this disease^. That this 

 would be the case we might have surmised from 

 analogy, for charcoal-dust is offensive to many in- 

 sects ; and is one of the most powerful preventives of 

 putrefaction known. Soot, I have reason to believe, 

 from a slight experience, is as effectual as charcoal 

 dust. Judging from theoretical reasons, we might 

 conclude that it would be more specifical, for in 

 addition to its being like charcoal, finely di\-ided 

 carbon, it contains sulphur, to which insects have 

 also a great antipathy. 



Mr. Drurey, a practical farmer at Erpingham, in 

 Norfolk, considered marl a certain preventive of this 

 disease. He and several other judicious farmers 

 also thought that teatJiing, that is, giving sheep and 

 cattle their green food, turnips, &c., upon the barley- 

 stubbles intended for turnips as the succeeding 

 crop, would cause the ambur}^^. It is ver}' evident 



^ Trans, of London Horticultural Soc. vi. art. 2. 

 ^ Marshall's Rural Economy of Norfolk, ii. 33-35. 



