338 * N «« B LIG HT IN WHEAT. 



Charcoal pow- If the addition of charcoal powder or siliceous sanii 

 Her or sand may contributes to the durability of drying oiI 9 it may pro* 

 bably have a similar effect on this composition ; but whe- 

 ther it may be best to mix them with the ingredients, or 

 apply them afterward, I cannot from experience tell. In 

 the latter case, the powder should be sifted on, while the 

 first coat of the composition is still hot ; and, after some 

 days, when that is dry, should have a brush gently passed 

 over it, in order to remove all the particles which do not 

 adhere ; after which other coats of the composition may be 

 applied, as before directed. 



This is all which occurs to me as to the mode of pre- 

 serving wood when exposed to the weather. 



(To be concluded in our next.) 





III. 



On the Blight in Wheat, By Mr. Thomas Davis, of 

 Horningsham *. 



^tfheat Wight a JL HE opinion I gave in the Bath Society's Papers, 

 plant. y o ^ x ^ p 41 ^ that thc w jj eat blight is a plant, and not 



an insect, is now fully confirmed by the microscopical ob- 

 servations of that able naturalist, Sir Joseph Banks, who, 

 in his treatise on the subject, has given magnified repret 

 sentations of the plant, in which its form and fructification 

 are so conspicuous, that no one can doubt the fact +. 



Sir Joseph also describes the manner in which the mi- 

 nute seeds of this plant (which are as light as air) are car- 

 ried by the wind, and lodged on the growing stalks of 

 wheat, where they take root and vegetate, and, like all 

 other parasitical plants, rob the plant to which they at- 

 tach of its nourishment, to support themselves. The ef- 

 Its destructive ^ ec * is * 00 we ^ known. The rapidity with which these 

 operation. minute plants vegetate, and the destruction they make in a 

 crop of wheat, of which the ears only a few days before 



* From the Bath Society's Papers, Vol. XI, pill. 

 t See Philos. Journal, Vol, X, p. 225, and Plates IX, X. 



appeared 



