Primary to Projecter

Primary-tape glider to Production

and' blue from which all other colours are made.

Primary-type glider. (Aero.) A rug­gedly built glider f~r elementary training of glider pilots.

Primavera. (Wood) A central Ameri­can tree. Incorrectly called white mahogany. It is creamy white in colour and darkens with age. Much used in veneered store in­teriors, window paneling, and for bedroom furniture.
Prime number. (Math.) Number hav­ing no common factors but unity.

Priming. (Paint.) Laying a first coat­ing, color, or preparation upon" a surface as in painting.

Priming paint. (Paint.) The first or ground coat of paint applied to a piece of work, to fill the pores of the surface.

Principle of moments. (Engine.) The algebraic sum of any number of forces with respect to a point, equals the moment of their resul­tant about that point.

Principles. Fundamental or general truths.

Printers mark. (Print.) A design or emblem used by a printer as a trademark.

Printing. The act or art of making, under pressure, an impression on paper or other material, as from type or printing plate, (SEE Ty­ POGRAPHY.)

Printing back. (Fdry.) Consists of replacing the pattern in the mold and tapping it lightly after the pattern was first removed and the cavity dusted with facing mate­rial. This method produces smooth castings.

Printing press. Any machine ~r press on which rapid reproduCtlon can be made on paper or other mate­rial by transferring ink from an original (as from type or a plate) by the application of pressure.
Prism. (Math.) A solid whose ends . are plane surfaces, equal and par­ allel, and whose sides are plane parallelograms. Prismoid.A body resembling a prism in form,

Process annealing. Alloys with'iron base are heated below or almost to the lower limit of the critical temperature range, and then cooled.

Process control engineer. A chemi­cal engineer whose duty it is to check and supervise the use of materials used in the manufactur­ing processes.

Process or chemical metallurgy. Has to do with melting and refin­ing of metals.

Process work. (Print.) A halftone process, by means of which coloured pictures are obtained, by the use of three or four colour plates prepared by the photo-en­graving process.

Product. (Engin.) In industrial work, the quantity of output or the out­put itself.

Product control engineer. One who looks after the testing and control of raw materials. Production. (1) Act of producing.(2) That which is produced or Production basis to Projecter made.(3)i factory work the quantity of output.Production basis.The manufacture of parts in quantities by the most economical methods.

Production engineer. One who is responsible for the maintenance of production. He also directs tool­ing operation and the design of fixtures and appliances to secure the most efficient manufacturing methods.

Productivity. The efficiency with which economic resources (men, materials, and machines) are em­ployed to produce goods and ser­vices. Profile. An outline, or contour.

Profile drag. (Aero.) The difference between the total wing drag and the induced drag.

Profileometer. An cxceedingly ac­curate instrument for measuring the smoothness or roughness of a surface. As a diamond-pointed tracer arm is moved across a surface, the arm, by moving a coil in an electric field, causes the generation of a current in proportion to the roughness of the surface. which is registered by an indicating needle.

Profile thickness. (Aero..) The maxi­mum distance between the upper and lower contours of an airfoil, measured perpendicularly to the mean line of the profile.

Profiling machine. (Mach.) A type of milling machine in which the cutter can be made to follow a profile or pattern. A very valu­able machine for cenaln dassses of work.

Progression. (Arith.) A progression in which a series of numbers in­creases or decreases by addition or subtraction. (Geom.) A pro­gression in which each of a se­ries of numbers increases or de­creases by multiplication or divi­sion.

Progressive proofs. (Print.) Colour plate proofs which serve as a guide to the pressman in select­ing the exact shades of colour and in determining their sequence in printing.

Projected propeller area. (Aero.) Projected blade area times the number of blades.

Projecting belt course. (Bldg.) Usu­ally an elaboration of a plain band course of masonry or cut-stone work projecting several inches be­yond the face of the wall.

Projection. (I) A jutting out, a prominenc. (2) In drawing, the method by which one or more views of an object are used as an aid in securing additional views.

Projection receiver. (Tel.) Televi­sion receiver incorporating a prin­cipal of optical projection as dis­tinguished from direct viewing television receiver.

Projection welding. A resistance­welding process wherein local­ization of heat between tw.o sur­faces or between the end of one member and the surface of an­other is effected by projections, Porojector. A device for projecting