Chapter II: )

=Mortise.=--A slot or cavity made in a piece of wood to receive the end of another piece. E. G. See Figs. 208, 210, 211, Chapter XV. Bevelled Mortise.--A mortise with its bottom or sides bevelled. E. G. See Fig. 10, Chapter I.

=Mould.=--Something which serves to give the proper form to an object. E. G. The mould for shaping a canvas canoe, Fig. 204, Chapter XV.

=Newel Post.= See Balustrade.

=Notch.=--A hollow cut in anything; a nick; an indentation. To Notch.--To cut in small hollows, as to notch a stick. E. G. See Fig. 191, Chapter XIV, and Fig. 392, Chapter XXVII.

=Obsidian.=--A form of lava.

=On Centres.=--In spacing studs or strips of any kind, they are spoken of as being placed a certain number of inches on centres. E. G. Twelve inches on centres means that the distance from the centre of one piece to the centre of another is twelve inches.

=Out of Plumb.=--Not vertical; not perpendicular to the horizon.

=Out of Square.=--Askew; oblique; not true.

=Parallel.=--Lines or objects are parallel to one another when they have the same direction, and all corresponding points are equidistant from one another.

=Perpendicular.=--Vertical; plumb; in an upright position.

=Perspective.=--A perspective is a drawing showing an object in the form in which it appears to the eye. The lines converge, or approach nearer together, as they go away from the eye, until they finally meet at a point on the horizon, or a line drawn to represent the horizon. E. G. In looking down a railway track the telegraph poles and tracks appear to run together on the line of the horizon.

=Pica.=--The standard of measurement in printing. A name given to a size of type which measures one-sixth of an inch high (measured from the nicked side to the side opposite); and seventy-two ems (see Em) measure one foot.

=Pie.=--A mixed assortment of type. See page 135, Chapter IX.

=Pieing Type or Making Pie.=--Spilling or mixing up type.

=Pipe-straps.=--Iron straps used mostly by pipe-fitters to fasten gas-piping in place. E. G. See Figs. 321 and 322.

=Pitch.=--The pitch of a board is the degree to which it has been tilted.

=Plan.=--A drawing showing a view of an object, looking down upon it, either on top of it (e. g. see Figs. 205 and 207), or with the upper portion sliced off (e. g. see Fig. 190. This shows a plan of the log-cabin at a level of the door and windows, with the upper portion removed).

=Plank.=--Lumber two inches or more in thickness is known as planks or planking. Anything of less thickness is known as boards.

=Plumb.=--Perpendicular; vertical; true. An instrument for determining whether or not an object is plumb (see Fig. 14, Chapter I).

=Proscenium.=--The front portion of a stage. The Proscenium Arch is the arch or frame extending around the front of the stage of a theatre.

=Pumice Stone.=--A porous rock, of extreme lightness, used for polishing metals; for smoothing the surface of wood; and for smoothing the surface of a coat of paint before applying a second coat (see Painting of Canvas Canoe, page 214).

=Pyrotechnics.=--The art of making fireworks; fireworks; the composition and use of fireworks.

=Quad.=--An abbreviation for quadrat. A block of type-metal lower than the type, used for filling out lines, and for spacing between lines. A 2-em quad is two "ems" in width, and a 3-em quad three "ems" in width.

=Quartz.=--Glassy crystals, having the form of a six-sided prism, terminated at each end by a pyramid. It is colorless, or transparent, when pure, and more or less opaque and in various colors when impure.

=Quoins.=--The wedges used to tighten or lock-up a form of type. E. G. See Figs. 155 and 156.

=Rabbet.=--A groove or hollow cut in a piece of work, generally for the purpose of joining it with some other material. E. G. The sides of the bow and stern pieces of the Canvas Canoe described in Chapter XV are rabbeted so the ribbands and the edge of the canvas will fit in them (see Figs. 200 and 202, Chapter XV).

=Radius.=--The distance from the centre of a circle to any point upon its circumference. It equals one-half of the length of the diameter.

=Rasp.=--A file with coarse teeth, used for working upon wood.

=Recess.=--A niche in a wall; a space or opening formed by the wall setting in a little way.

=Reënforce.=--To strengthen; to supply additional strength with strips or braces.

=Ridge.=--An edge of a roof formed by the meeting of two sloping surfaces. The top edge of a peaked roof. E. G. See Fig. 192, Chapter XIV.

=Ridge-boards.=--The boards fastened along the ridge of a roof to cover the joint. E. G. See Fig. 192, Chapter XIV.

=Right Angle.=--An angle of ninety degrees. At Right Angles.--So as to form a right angle.

=Rubbing Down.=--Bringing to a smooth surface by rubbing with sand-paper, emery-paper, or pumice stone.

=Rustic.=--Made of limbs of trees in their natural form.

=Sagging.=--The bending of a body by its own weight, or by a load placed upon it.

=Sapling.=--A young tree.

=Sash.=--The frame which holds the glass of a window. Also applied to the frame with the glass in place.

=Scraping.=--A piece of glass or the blade removed from a plane is used for scraping a piece of work to give it a smoother surface than can be obtained by using a plane upon it.

=Section.=--A part.

=Section Drawing.=--A drawing made of an object, showing it as it would look if you were to cut it open or split it in two. The portions which would have to be cut through, in such an operation, are shaded in a drawing of this kind. E. G. See Fig. 218, Chapter XV; Fig. 300, Chapter XXI; and Fig. 316, Chapter XXII.

A Cross Section is a section taken through the short way of an object.

A Longitudinal Section is a section taken through the long way of an object.

=Selvage.=--The selvage of cloth or wire-mesh is the edge which has been so woven as to prevent ravelling.

=Semicircle.=--Half a circle.

=Set of a Saw's Teeth.= See page 21, Chapter II.

=Setting Nails.= See page 34, Chapter II.

=Shape it Down.=--A term used to imply that the board or piece of work shall be gradually cut down until it approaches its finished form and size.

=Shooting Stick.=--An iron or wooden tool with a head on one end, used to lock-up the Quoins in a form of type. E. G. See Fig. 155, Chapter IX.

=Sills.=--The lowest horizontal timbers in a building of any kind on which the structure rests. See also Window Frame.

=Sleepers.=--The timbers supporting the lower floor of a building, distinguished from joists by being filled in between with cinders or concrete. E. G. See Fig. 186, Chapter XIII.

=Slip-knot.=--A noose which slips along the line or rope around which it is tied. E. G. See Fig. 243, Chapter XVII.

=Slot.=--A mortise, or hole, with sides square or nearly so. Made by boring several holes, and then connecting and squaring them up with a chisel.

=Space.=--A thin piece of type-metal, lower than the type, used between words, and for spacing out lines. A 3-em space is a third of an "em" in width, a 4-em a quarter of an "em" in width, a 5-em a fifth of an "em," and an 8-em (known as a hair space) is an eighth of an "em."

=Spike.=--A twentypenny nail (four inches long) and all lengths greater. See list of sizes on page 36, Chapter II. To Spike a board in place is to fasten it with spikes.

=Spliced.=--Two pieces are spliced when joined together, generally end to end, in such a way that they are held together and act as one piece. E. G. See Fig. 183, Chapter XIII, and Fishing.

=Spring-catch.=--A small lock, such as shown in Figs. 96, 114, and 187. The latch is operated by a small knob, and is thrown into position by a small spring. The metal socket which is screwed in place for the latch to spring into is known as the Latch-pocket.

=Sprint.=--A short race run at full speed.

=Squaring Lines.=--By squaring lines across a board is meant the operation of drawing lines across a board with a try-square, the head of the try-square being placed against the tried-edge of the board so those lines will be at right angles to that tried-edge. E. G. See Fig. 38,