I 
3 75 
gives the first symptoms of it ; this smell* which is the con* 
sequence of the complete loss ot its aromatic principle, proves 
that the critical time is already past. 
If the stone trough should be filled too much, some of the 
mash will run out irl grinding, and if it is not sufficiently full, 
the work will go on too slowly. With a view, therefore, of 
keeping a proper medium, and saving time, it is desirable to 
fix in the floor, above the grinder, a mill hopper of an ade¬ 
quate size, communicating with it by means of a pipe, through 
which the fruit may be distributed as it is wanted to be 
ground. 
The apple juice, which is of a pale white at the time that it 
is pressed, shows that when it is exposed to the action of 
the air, somfe property of that fluid deepens its colour;* the 
following experiments afford a proof of it: — 
First experiment .—Having cut an apple in two, I immediately 
covered the surface of one of the halves with a piece of 
glass, and left the other exposed to the air; the latter almost 
immediately became of a yellow brown; but the former was 
not altered twenty-four hours after, when I removed the glass. 
Second experiment .—I cut another apple, placing one of the 
parts under the receiver of an air-pump, and then pumping 
out the air as much as the machine would allow. The surface 
which had been cut, was very little altered two days after 
when I took it out. 
It is proper then to make small trougn-fulls, not only with 
respect to cleanliness, but because the mash, by being exposed 
to the influence of the atmosphere, more easily absorbs its 
oxigen, which is the generating principle of acid, which 
heightens the colour of ground fruit, and improves its sac¬ 
charine quality. This practice becomes indispensable, when 
the fruit has been ground before it is quite ripe. The mash 
is sufficiently ground, when it falls gently after the wheel, and 
detaches itself from the sides of the trough. 
It requires to be allowed ti ue to incorporate itself together; 
the greener the fruit was, the longer it should be left to stand; 
that of fruit fully ripe requires a space of from ten to twelve 
hours, and the other in proportion. 
Wooden shovels are the only ones fit for use, iron ones being 
liable to turn the cider black. The malic acid, being always 
combined with an astringent principle, when it comes in con¬ 
tact with this metal, produces a kind of ink. 
* It is now known, that atmospherical air, which vvas formerly considered 
a simple substance as an element, is itself compounded in this climate of 
nearly 0'27 of oxigen gas, of 0 7.2 of azotic gas, and of 0-1 of carbonic gas. 
CHAPTER 
