‘USEFUL PROJECTS. 
_ the inspection of the society a small 
~Fer 
quantity of the flour of potatoe sent 
herewith. 
Tie potatoes were boiled with 
their skin on, dried on a kiln, and 
_ the whole ground in a steel corn- 
mill: none of the skin has been 
separated by dressing. 
By experiments that have been 
before made on fine dried flour of 
potatoes, it is known, that it will 
keep longer than the flour of wheat 
without spoiling ; that it is used as a 
substitute for sago, and makes good 
biscuits without admixture. And | 
have every reason to believeit will mix 
and make good bread,in a much larger 
proportion with wheat-flour, than 
has hitherto been employed of the 
boiled root, in the common mode of 
using it. Of the expence of pre- 
paring the flour from the root in 
 Jarge quantities 1 am not prepared 
to speak. ‘he chief labour is wash- 
ing the potatoes from the mould, 
which adheres to the eyes, particu- 
_ larly in those sorts, the eyes of which 
are much depressed. Drying them 
will be considerably expensive; but 
_ I think may be reduced much below 
what at first it will be estimated at. 
_ Grinding will not cost more than 
corn. 
From what I believe were accu- 
rate experiments, I find that 100 fts 
__ of washed potatees will produce full 
— little, 
25 ibs of flour (such as the sample.) 
The difference in weight will be very 
whether the potatoes are 
boiled, or only ground in an apple- 
~ 
dried. 
mill, and the juice suffered slowly to 
drain from them before they are 
It might seem, therefore, at 
first view, that the boiling might be 
omitted ; my trials however have 
shewn me, that the colour of the 
flower is much fairer when boiled, 
and the taste more pleasant; and, 
963 
that the expence of boiling in steam 
is very little. With the greatest 
care even some of the starch (the 
most nutritive part of the root) will 
separate with the juice ; above 3 ths 
of the fine starch, (weighed after it 
was dried) passed off with the water 
from 100 tbs of potatoe. Other 
persons will, [ trust, ascertain suck 
facts with more accuracy ; 1, myself, 
hope soon to ascertain more satis- 
factory particulars. In the mean 
time, permit me to make an estimate 
of the probable produce of au acre 
of potatoes in quaatity, when re- 
duced to the state of flour. 
The average produce of an acre, 
managed with care, is estimated at 
about 80 sacks of 240 ibs each. 
According to my experiments (as 
before,) 100 tbs of washed potatoes 
will produce 25 its. of dry flour ; 
or each sack O0tbs.; or one acre, 
two tons and upwards, 
I am not qualified at present to 
carry these calculations farther—if 
quantity alone be the question, I 
need not, 
Note. The potatoes used in the 
foregoing trials were the red apple 
potatoe. 
The steel-mill has not ground this 
flour so fine as { believe a stone-milk 
would have done. Some of these 
had their skins stripped off after 
boiling. Should an expeditious me- 
thod be found of stripping off the 
skins, it will, perhaps, be less trou- 
blesome than washing so carefully 
as must be otherwise practised. 
After giving a numerical account 
of the samples of flour of potatoe 
prepared for exhibition, this gentie- 
man gives also samples of bread and 
biscuit made from different sorts of 
potatoe flour, mixed with different 
proportions of wheat flour of difier- 
ent degrees of fineness ; but these 
3Q2 would 
