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XIV. Observations on the Grafting of Trees. In a Letter from 
Thomas Andrew Knight, Esq. to Sir Joseph Banks, Bart . 
P.R.S. 
Read April 30, 1795. 
SIR, 
I am encouraged to address the following letter to you, by 
the opinion you were last year pleased to express of part of 
my experiments and observations, on the diseases and decay 
of those varieties of the apple and pear which have been long 
in cultivation. The disease from whose ravages they suffer 
most is the canker, the effects of which are generally first seen 
in the winter, or when the sap is first rising in the spring. 
The bark becomes discoloured in spots, under which the wood, 
in the annual shoots, is dead to the centre, and in the older 
branches, to the depth of the last summer's growth. Previous 
to making any experiments, I had conversed with several 
planters, who entertained an opinion, that it was impossible 
to obtain healthy trees of those varieties which flourished in 
the beginning and middle of the present century, and which 
now form the largest orchards in this country. The appear- 
ance of the young trees, which I had seen, justified the con- 
clusion they had drawn ; but the silence of every writer on the 
subject of planting, which had come in my way, convinced 
me that it was a vulgar error, and the following experiments 
were undertaken to prove it so. 
