BOARD MACHINES 249

Each chest requires a separate stuff pump, and where stocks of diiferent
colours are being used, separate back-water pumps and tanks are needed to
pump back and store the water from the vats for the beaters or mixing boxes.
From the foregoing it will be gathered that the wet end of a multi-vat machine
is a somewhat complicated and costly affair.

FIG. 104.— VATS AND COUCH Rons OP A MUITIKJ&-VAT BOABD MACHWE

To take the case of a four-vat machine: The vats are arranged close together,
and in rotation, the first one to deliver its web of stuff to the wet felt being che
one nearest the presses, and so on in a reverse direction towards die strainers.
When the fourth web has been picked up, the felt will be fairly heavily loaded,
and here it turns round a roll and travels back towards die presses of tfae machine
carrying the four-ply web on top and immediately above dbe vats.