170 WET SUMMERS. 
The lichens of Dartmoor also, are remarkable for 
- their variety and exuberent growth. 
Wet summers, such as that of 1838, are particu- 
larly unfavorable to the crops of wheat, because 
they give rise to an infinite quantity of minute 
fungous vegetable growths on all parts of the grain, 
its bracteas, awn, &c. and they attack the plants 
so early as to prevent the proper maturation of the 
grain. This parasite is called by farmers “ yellows,” 
but though it is at first of that colour, a great deal 
soon becomes grey and black. A small patch of 
Victoria wheat which I raised in my garden in 1838 
was thoroughly destroyed by the “ yellows,” not a 
single grain turning so as to be available for flour. 
In our present ignorance of the nature of elec- 
tricity, it is hardly possible to count correctly on 
its probable extent of power in the production of 
those subtle forms of being called “ blights,” but it 
will be proper to keep alive in our minds a suspi- 
cion of its extensive operation on the latent or 
deficient vitality of the microscopic class, even from 
the few facts in our possession which seemingly 
point to that source as the vivifying influence ; and 
it will be proper also to recollect the experiment 
recently performed of passing an electric stream 
through water, upon which there appeared therein 
multitudes of microscopic animalcules. 
I subjoin here a comparative view of the mean 
heat of each month of the year 1806 taken at two 
situations in this county of those opposite kinds 
which in accordance with what I have already 
expressed, ought to (as they really do) shew the 
“its dimensions being no less than 31 feet in circumference and 
“ rising 7 or 8 feet before it separates into 3 branches each the 
“size of a large tree.’—Journal of ten days excursion to northern 
and western borders of Darimoor. 
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