Chap. XIII.

TOOLS AND MACHINES.

1041

be graduated to work at any angle or bevel. A motion is given to the frame which holdsthe cutter, by which, at the end of every stroke, it rises, to allow the carriage on which theiron to be planed rests, to pass back free to the cutter, which a workman adjusts after everystroke. The ease with which shaving after shaving is taken from the iron renders this in-vention one of the greatest practical utility : in many manufactories there are now planingmachines which can at once smooth down a surface upwards of 15 feet in length with aface of 10 inches, and for this purpose the chisel and the file are laid aside.

Most of these machines originated from im-provements made by Mr. J. Bramah, who in 1802obtained a patent for the purpose of producingstraight, smooth, and parallel, curvilinear surfaces,in a more expeditious manner than could beperformed by axes, saws, planes, or other cuttinginstruments used by band.

The planing tool in some of the later machinesis fixed at j; b is the cylinder or work to be facedor planed ; motion is given to the drum h by thespur-gear g g ; t is a hollow cylindrical frame, onwhich the slide works, and by means of leversshown at m, the planing tool is made to come incontact with the work it has to perform.

Forge Bellows , formerly much used on the con-tinent, consisted of two pipes, which conductedwater from a stream about 10 or 15 feet in height,into others placed vertically over a tub which wassunk in the basement of the building where theblast was to be conveyed : over the middle ofthe top of the tub was raised a small pyramid,having at its summit a pipe through which theblast passed to the forge at A ; the power wasobtained by the water falling from a heightsufficient to compress the air within the smallpyramid, and causing it to mount and force itsway out at the mouth of the pipe ; this mayhe considered an application of the hydrostaticpress for the purpose of obtaining a blast; theplan represents a forge on the lsere, betweenKamand and Grenoble . The blower consistsof a tub,/*/, of an oval form, 7 feet long,and 3 or 4 feet wide. The edges are let into ^»g. forge worked by a fall of water.the ground 5 or 6 inches to prevent the air from entering ; to the top of this cisternor tub two wooden pipes B, C, 10 or 12 fo^t high, are attached,these, is a kind

of pyramid, G, ^ F E

having a tube Dat the top, whichconducts the air tothe forge. A smalltrough, 1 foot wideand 7 or 8 inchesdeep, divided intotwo branches E, F,conducts the waterinto the pipes B, Cin a greater or lessquantity, accordingas we wish to in-crease or diminishthe quantity of wind,by means of a sluicein the trough. Asthe pipes B, C haveseveral holes neartheir summit in-clined inwards, bywhich air is ad-mitted, the water in

In the middle, between

K i*. 1599.

FORGE BELLOWS.