84 
thus raifed produced plants that 
were curled. 
The forcing potatoes by cultiva- 
tion, as above defcribed, I find tobe 
the caufe of the curl, both from my 
own experiments, repeated for feve- 
ral years fucceflively, and alio trom 
the obfervations I have made upon 
the praétice and ill fuccefs of my 
neighbours, 
It is well known that the flowers 
of many plants, fuch as the poppy, 
the rofe, and many others, are much 
altered by cultivation; they become 
double, the ftamina are converied 
into petals, the generic character is 
loft, they become what botanilts call 
Monfters; the parts of generation 
being changed, no feed is produced. 
‘If I may be allowed to confider 
‘any part of a plant in which the 
vegetative power refides as a feed, 
it will be found that rich. cultiva- 
tion produces, if not abfolutely the 
fame, at leaft a fimilar imperfection 
in the potatoe; for, the flower and 
‘the bulbous root are both enlarged 
by cultivation. In the flower, little 
or no feed is produced: in the po- 
tatoe, the vegetative power is 1m- 
paired or deftroyed, according to 
the degree of the difeafe. 
It is obfervable that, wherever 
the vegetative power is impaired, 
there is «lways.a deficiency of 
moifture; which is proved by the 
following experiment, from which 
it appears, that both healthy and 
curled plants may be raifed from 
the fame potatoe. 
Dig up, in the beginning of Oc- 
tober, fome potatoes raifed as is 
defcribed in the preceding pages. 
Amongft the largeft will be found 
fome that have, in different parts, 
different degrees of moifture, the 
Jeaft at the butt, and the moft at 
the crown end, the quantity of 
ANNUAL REGISTER, 
1790. 
moifture gradually inereafing from 
the butt to the crown. Take one 
fet from the crown, and another 
from the butt; the former-will pro- 
duce an healthy, the Jatter a curled 
plant. The curl-producing pota> 
toes are alfo obferved to: be drier 
both before and after boiling, and 
are boiled in a fhorter time. 
ee 
The Mode of preventing the Curl in 
Potatoes, 
The following direétions for cul- 
tivating potatoes, duly obferved, will 
effectually prevent the curl; as 1 
have found by various and repeated 
experiments, made with great care 
and attention, during thefe laft feven 
years. 
The beft time of fetting, is from 
the beginning of April to the middle 
of May. Make ridges a yard a- 
funder ; put your manure firft into 
the trench, and with moderation: 
fet the potatoes in a triangular 
form, five or fix inches afunder; 
cover them with the foil to the 
thicknefs of five or fix inches. 
There js but little danger of laying 
on too much of the foil: the deeper 
are the fets, the better will they be. 
protected from the fcorching heat 
of the fun, if the feafon fhould be 
dry. This difance of five or fix 
inches is fo {mall as to prevent the 
plants growing too rank, and yet 
fufiicient for each of them to be ex- 
pofed to the fun and the air. 
zdly. When they have grown to 
the height of fix or feven inches 
above the ground, yeu muft not 
earth them, as is the ufual practice. 
You muit take away the -weeds, 
and may draw a little mould te 
them; but you muft be careful to 
do it before the bloffom-buds appear, 
_ which 
