on the Grafting of Trees . 295 
tarine trees may, I think, arise from the same source. The 
oak is much more long-lived in the north of Europe than 
here ; though its timber is less durable, from the numerous 
pores attending its slow growth. The climate of this country 
being colder than its native, may in the same way add to the 
durability of the elm ; which may possibly be further in- 
creased by its not producing seeds in this climate, as the life 
of many annuals may be' increased to twice its natural period, 
if not more, by preventing their seeding. 
I have been induced to say a great deal more on this sub- 
ject than, I fear, you will think it deserves, from a conviction 
that immense advantages would arise from the cultivation of 
the pear and apple in other counties, and that the ill success 
which has attended any efforts to propagate them, has arisen 
from the use of worn out and diseased kinds. Their cultiva- 
tion is ill understood in this country, and worse practised ; 
yet an acre of ground, fully planted, frequently affords an 
average produce of more than five hundred gallons of liquor, 
with a tolerably good crop of grass ; and I have not the least 
doubt but that there are large quantities of ground in almost 
every county in England capable of affording an equal produce. 
I have only to add an assurance, that the results of the fore- 
going experiments are correctly stated ; and that 
I am, Sir, See. * 
Elton, Herefordshire, 
April i 3 , 170s. THO. AND. KNIGHT. 
Qq 
% 
