CHAPTER XIV. 
Of the Single Screw, eznd the Double Screw—A new Construction of tins 
latter Press—A Mode of repairing the Head of Broken Screws — Hy¬ 
drostatic Press. 
It would be foreign to the purpose to give a detail of all 
the utensils which are made use of in making cider; but as the 
single screw, and the double screw, the only presses in use 
among us, are pieces of the utmost importance, it will be pro¬ 
per to give here a sketch of their respective advantages. 
' The English make a great use ot the single screw. That 
press, which always acts in a direction perpendicular to its 
base, acquires an immense force by means of a nut of brass, 
and an iron screw. After the first expense, the proprietor 
will be for a long time without being obliged to have recourse, 
to any repairs, which is a consideration of great weight; it is, 
however, a sort of improvement vfcry rare among us, on ac¬ 
count of the expense into which it draws the grower. 
Being totally made of wood, the double screw deserves the 
preference; because, in this respect, theory and practice agree 
perfectly weli together. In fact, Without being originally 
dearer than the other, it lasts as long, and augments its force, 
when it becomes most necessary to it, that is, in proportion to 
its sinking; while the single screw loses bis in the sanie ratios 
one man can manage the double screw without adding blocks. 
The single screw wants some to be added, according to the 
degree the cheese sinks in, and requires to be raised up, when 
they are to be added ; but this is a tiresome work, and which 
wastes time. In the former case, one screw draws assistance 
from tli'e other screw ; in the latter, it acts by Itself. The 
former of these presses becomes stronger by the elasticity of 
the beams; the latter works by a vis inertia, which diminishes 
every moment. 
The double screw is made still more advantageous, by join¬ 
ing nuts of wood strongly secured with hands of iron, and 
fixed with the hinges of the same metal to the second beam, 
at 
