Desigller to Diamond.

Designer or layout man. One qualified through wide experience to prepare designs of the type of product manufatured by his firm.
Designing engineer. One who looks after the engineering and specifi­cations of an assignment. He is responsible for efficient and eco­nomical design and approves all layouts before they are detailed.
Desk. Common term used to describe the small to medium sized mixers in studios or on the road.
Destructive distillation. (Chern.) Heating a substance out of contact with air in order to decompose it and obtain new and often useful products. It differs from ordinary distillation in that it results in chemi­cal change as opposed to physical change resulting from plain distil­lation.
Detach. To disconnect, to remove. In shop practice, frequently, in order to'make adjustments or change the setup for other operations.
Detail. One of the constituent parts. A separately considered portion of
anything. A minor essential part, necessary yet secondary.
Detail drawing. (Draft.) A drawing showing details of a machine or other object with complete tabulardata, dimensions, material used, number of pieces, operations to be performed. Not an assembly draw­mg.
Detailer. A draftsman who prepares
the detail drawings for shop use.
Detector. (Elec.) A device for con­veriing inaudible radio frequency signals into audible frequency sig­nals.
Deterioration. The state or process of growing worse.
Determine. To find the value of mathematically, by exact measure­ment.
Detonate. (Auto.) To cause gases un­der compression to expand rapidly through application of heat or flame.
Detonation. Rapid combustion re­placing normal combustion dis­closed by loss of power, engine overheating, etc.; also, an explo­sIOn.
Detonator. A cap in which a spark from an electrically heated wire sets off an explosive charge with sufficient violence to explode a greater charge of dynamite.
Deuterium. (Chern.) Heavy hydro­gen: hydrogen electrons opposed to ordinary atoms of hydrogen which contain' only one proton and electron.
Develop. To draw a pauern of. To unfold gradually; make known in detai I.
Development. A drawing represent­ ing a paUern or layout.
Development engineer. Primarily an experimental engineer. He must be

Deviation. Departure from the exact or from a set standard. Variation; error.
Device. A mechanical aid or contri­vance which serves to promote the better performance of a job.
Devil. An apprentice, or one who does odd jobs in connection with the work, as printer's devil.
Dextrin. (Wood Fin.) An amorphous, colourless compound found in nature as in the sap of plants, soluble in water; is used as substitute for gum arabk.
Diagonal. (Math.) A straight, oblique line, such as would divide a rectan­gle into equal right triangles. (Engin.) The braces, struts, and ties of a lattice girder are its diagonals.
Diagonal bond. (Masonry) Bricks laid obliquely in a wall as often is seen in the end walls of colonial houses.
Diagonal parting. (Wood Patmkg.) The parting of pattern of rectangu­lar cross-section on its diagonal. Such a method of parting facilitates th removal of the pattern from the sand, and the setting of the core.
Diagram. An outline drawing, or graphic representation.
Dial. A graduated plate, usually cir­cular or oval, on which a reading is indicated by a needle or pointer.
Dial bridge. (Elec.) A resistance bridge having its coils arranged in dials, the .contacts being m~de- by a moveable arm instead of by the insertion of plugs.
Dial gauge. A dial having an index hand actuated by a bent spring, through which the amount of pres­sure or the cacuum is indicated. All gauges or of this kind are made on Bourdon's spring principle.

Diameter. A straight line passing through the center of a circle. its ends terminating in the circum­ference. (Math.)' Diameter = circumference x 0.3183. .r
Diametral pitch. (Gear.) The rela­tion, or ratio, existing between the number of teeth on a gear and its pitch diameter. If a gear has 40 teeth and its pitch diameter is 10, the diametral pitch is 4, etc.
Diamond. (Chern.) A crystalline form of carbon. The hardest known min­eral. (Print.) Type of four and one