452 Review of Dr. Wetherill’s 
The second part of the work describes several different arrangements 
of the apparatus for making vinegar as well as various modes of work- 
ing; and one about to start or remodel a manufactory, would derive 
much advantage from a careful study of the many plans here detailed. 
Yet some questions might be asked to which the book gives no satis- 
factory answer. The first point to be decided is, of valu size shall the 
graduators be made? They commonly have an average diameter of 
about 34 feet and a height not exceeding 12 feet. But they seem to 
e so made rather from precedent than from any actual necessity. It is 
vie likely coo there would be some advantage in having them much 
liq 
20 feet of ailing. drawn out at one as finished vine gar. ese ong 
graduators produce quite as much strong vinegar for the same amoun 
of filling as those of half on height worked in pairs; and sent escir 
be the feeding apparatus to be described presently, they dispense 
be a large part of the labor and attention required in the older ways 
of working. 
os to the form of the generators, a word may be said. They are made 
mewhat conical so that the hoops may be driven tight; but which 
advantage in having them so set. It is true the filling usually shrinks 
more or less in the course of time, and one might suppose that were the 
taper from the bottom upwards, the filling would draw away from the 
sides and leave there too free a passage for the air. But it is a some- 
what yielding mass we have to deal with. Therefore while it is short- 
ened vertically it presses 3 laterally. There are on the other hand 
There i is much difference of opinion and practice with reference to — 
ion of air. Some “practical” men insist on bori 
three or four feet above the false bottom. Others make them an ay 
or two above. Some lay pies stress on vgn ee in the air by one or 
terminating just below a miei beatin. on. Whiah’ the filling rests 
They forget that air is an alastie fluid and tends to diffuse itself equally _ 
