er; they are then carried on endless cords under
the coating trough described farther on. After they have been coated
they are carried onward upon a series of four broad endless bands of
absorbent cotton--Turkish toweling answers well--and this cotton is
kept constantly soaked with cold water, which flows over sheets of
accurately leveled plate glass below and in contact with the toweling;
the backs of the plates being thus kept in contact with fresh cold
water, the emulsion upon them is soon cooled down and is firmly set by
the time the plates have reached the end of the series of four wet
tables. They are then received upon one over which dry toweling
travels, which absorbs most of the moisture which may be clinging to
the backs of the plates; very little wet comes off the backs, so that
during a day's work it is not necessary to adopt special means to
redry this last endless band. What are technically known as "whole
plates," which are 81/2 in. by 61/2 in., are placed touching each other
end to end as they enter the machine, and they travel through it at
the rate of 720 per hour; smaller sizes are coated in proportion, the
smaller the plates the larger is the number coated in a given time.
The smaller plates pass through the machine in two parallel rows,
instead of in a single row, so that quarter plates, 41/4 in. by 31/4 in.,
are delivered at the end of the machine at the rate of 2,800 per hour,
keeping two attendants well employed in picking them up and placing
them in racks as quickly as they can do the work. The double row of
cords for carrying two lines of small plates through the machine is
represented in the engraving. Although the plates touch each other at
their edges on entering the machine, they are separated from each
other by short intervals after being coated; this is effected by
differential gearing. The water flowing over the tables for cooling
the plates is caught in receptacles below and carried away by pipes.
Between each of the tables is a little roller to enable small plates
to travel without tilting over the necessary gap between each pair of
bands.

[Illustration: Fig. 8.]

The feeding trough of Cadett's machine is represented in Fig. 8. The
plates, cleaned as already described, are carried upon the cords under
a brass roller, the weight of which causes sufficient friction to keep
the plates from tilting; they next pass under a soft camel's hair
brush to remove anything in the shape of dust o