20.1 Mr. W. Jones on the Mildeiv in Wheat. 



it in different stacks. These concavities, wherever they are, retaining the water 

 longer, must of course be more damp than the higher level ground, and afford the 

 more vapour to be exhaled from it, and the plants so situated, which in cold nights 

 becomes so condensed as to fix, and probably freeze* on the stalk, thereby destroy- 

 ing the texture of it, and suffering the sap to escape, as well as too gre;\t an exu- 

 dation of the perspirable matter through the longitudinal cracks that are apparent 

 in it, favouring the growth of the fungus ; when the wheat in the dryer and more 

 level ground affords less vapour, and from its higher situation more in the in- 

 fluence of the wind and its undulating motion to disperse it, and prevent the 

 injury. 



Was a thermometer to be placed in one of these cavities, and another on the 

 higher level ground, the former would be found to be the coldest situation, and in 

 degree proportionate to the dampness of the ground ; but for this we have the 

 evidence of our own senses ; as every man who has had occasion to go an hour or 

 two after sun setting in the summer from a high point of land, and pass over low 

 swampy lands, when a mist is over them, must have felt its chilling influence. The 

 lands I occupy are light, and some of them have been for many years in a rotation 

 of three crops, of turnips, wheat, and vetches. The manure applied to the turnip 

 crop consisting of lime, and earth taken up near the hedges, but no dung ; which 

 I consider to render the straw too luxuriant, more porous, and more subject to the 

 injury complained of, the progress of which I have attentively watched in all its 

 stages on the different sorts of wheat, to ascertain which is less liable to it, the most 

 proper time to cut it, and the mode of management afterwards, which brings me to 

 the second part. 



Since seasons cannot be altered, or frost prevented, it behoves us to endeavour 

 to procure such sort of wheat as is known to ripen earliest, and of the hardiest 

 kind ; the former may be acquired by selecting the most early ripe ears in the 

 same field, and increasing the quantity by degrees; for nature produces varieties 

 of species of the same genus, and it is for man to observe and embrace ihem to his 

 advantage. As to the hardiest kind, I should think higher latitudes in the North 

 of Europe most likely to furnish it, much more so than North America, because 



« Wc know that water, when frozen, is increased in bulk ; may not, therefore, the aqueous 

 particles resting on tlie stalk, in conjunction with the sap, be so frozen as to separate the fibres of 

 the stalk by their expansion ? 



