In practice there is occasionally found a slight irregularity in the thickness of slugs, and thin fins are sometimes cast around the forward edges.  For the purpose of reducing them to a uniform thickness, they are driven on their way to the galley between two vertical knives, as shown in Figs. 4 and 16.  The inner knife is stationary, but the outer knife is adjustable in order that it may accommodate slugs of different thicknesses.  This adjustment is made by the knife being seated at its outer edge against a supporting bar or wedge, having at opposite ends two inclined surfaces seated against supporting screws in the knife-block.  A lever engages a pin on the wedge for the purpose of moving it endwise; when moving in one direction, it forces the knife inward toward the stationary knife, and when moved in the other direction, it forces it to retreat under the influence of a spring seated in the block.  The wedge is provided with a series of teeth engaged by a spring-actuated pin or dog, whereby the wedge and the knife are stopped in proper positions to insure the exact space required between the two knives.

[Illustration:  Fig. 15.]

The back knife, secured to the frame for trimming the base of the slug as it is carried past by the revolving wheel, should be kept moderately sharp and adjusted so as to fit closely against the back of the passing mold.  Particular attention should be paid to this feature.  The edge of the knife must bear uniformly across the face of the mold.

[Illustration:  Fig. 16.]

The front knives, between which the slug is ejected, should not be made too sharp.  After being sharpened, the thin edge can be advantageously removed by the use of a thin oilstone applied against the side face; that is, against the face past which the slug is carried.

The stationary or left-hand knife should be so adjusted as to align exactly with the inner side of the mold.  Under proper conditions this knife does not trim the side face of the slug, but acts only to remove any slight fins or projections at the front edge.

The right-hand knife, adjustable by means of a wedge and lever, should stand exactly parallel with the stationary knife.  It trims the side of the slug on which the ribs are formed, and it serves to bring the slug to the exact thickness required.

FOOTNOTES: 

[Footnote 2:  From Theodore L. De Vinne’s Modern Methods of Book Composition, pp. 403-425.  The Century Company, New York, 1904.]

THE EXPOSITION OF A PROCESS IN NATURE

THE PEA WEEVIL[3]

Jean Henri Fabre

Peas are held in high esteem by mankind.  From remote ages man has endeavored, by careful culture, to produce larger, tenderer, and sweeter varieties.  Of an adaptable character, under careful treatment the plant has evolved in a docile fashion, and has ended by giving us what the ambition of the gardener desired.  To-day we have gone far beyond the yield of the Varrons and Columelles, and further still beyond the original pea; from the wild seeds confided to the soil by the first man who thought to scratch up the surface of the earth, perhaps with the half-jaw of a cave-bear, whose powerful canine tooth would serve him as a ploughshare!