To make the ink flow well, the cloth should be well rubbed with powdered chalk or talcum, which should be carefully wiped off with a cloth. This will remove any oily particles which would tend to prevent the ink from flowing upon the surface evenly. To make the cloth lie flat, the selvage edge should be torn off. The cloth should be well tacked to the board, the thumb-tacks being not over ten to twelve inches apart. In erasing, care must be taken not to spoil the surface of the tracing, and a knife should not be used except for very fine work, and when used it must be extremely sharp. The safest way is to use a sand rubber, even though it erase more than necessary. It will not destroy the surface, and after a little powdered talcum has been well rubbed on the erased part, it may be inked again as well as at first. If tracing-cloth is not available, the paper drawings may be inked in, thus giving an idea of the use of drawing ink.

In completing the various problems, the construction lines may be drawn in full red lines, or in fine full or dotted black lines, the finished lines being drawn strongly in black. In later and more advanced work, construction lines are omitted. Before any ink work is done, at least one sheet should be made for practice in using the ruling pen, using various widths of line, dotted, dot and dash, and dash lines, to accustom one's self to the behavior of the drawing ink and ruling pen. It will be well to attempt drawing lines tangent to circles, which may also be drawn for practice. As previously stated, Whatman's paper is most commonly used for school work, and this undoubtedly makes the neatest looking drawing; but if tracing-cloth is available, manila detail paper will be preferable, as it is more commonly used in drawing-rooms, and the student can be working on the line of future practice. The cost of tracing-cloth is higher than Whatman's paper, and therefore it will be well to adopt a standard size of sheet as small as convenient. Amateur Work is 73/4" x 105/8|", and this is about the size of a standard letter sheet, If we adopt a standard 71/2xl01/2 single and 15 x 101/2 double, it will work out very nicely. Manila paper may be obtained 22 x30 (which will make four standard sheets) at about 60 cents per quire. This is about three standard sheets for two cents. Tracing-cloth may be obtained 30" wide at about 28 cents per yard, and a sheet 22 x 30 will cost about 18 cents, which is 41/2 cents per standard sheet. The practice sheet may be used to help in learning the use of triangles and tee square, in drawing horizontal and vertical lines without having to use the problems which have been given above.

Having become fairly accustomed to the use of instruments, the next step will be to make a drawing showing three views of some simple object. Before this is done, a brief explanation of the rudiments of projection will be necessary. A mechanical drawing is never a picture, nor a perspective view. It is assumed that the eye is directly over each point of the object at the same time, and the dotted line is used to show parts which are hidden from external view. In other words, a mechanical drawing shows an object as if it were transparent or as if the X-rays were thrown on it. It must not be loaded with unnecessary detail, but it must contain enough to convey to the workman the necessary information to complete the work which it depicts. A simple object may be shown by two views, but it is customary - to always show three views, and where the object is very irregular, additional sectional views may be taken.

A convenient arrangement places the plan in the lower left-hand corner of the sheet, with a front elevation directly above it, and an end view on the right. This leaves space for the title in the lower right-hand corner, where it is most conveniently seen as the sheet lies in the drawer. There is no established standard as to arrangement of views, but this has been found very convenient. The sheet should be numbered in the lower right-hand and upper left-hand corners, so that in case it gets into the drawer inverted, its number may be easily seen. The views must be placed in projection ; that is, the center line of the front elevation will be directly above that of the plan, and that of the side view will be exactly in line with that of the front view and to the right. Let us take for our first regular drawing a steam-pipe-reducing tee. First locate the main center lines and begin to block out the views, carrying all three views along as closely as possible, as errors are more readily detected than when the views are finished separately. When the outlines of all three views are complete, then fill in the dotted lines and details, and finally line the pencil drawing in, preparatory to tracing. The drawing is now ready for the figures. Too much stress cannot be placed on the importance of this part of the work. A drawing may be perfect so far as lines and scale are concerned, yet may be entirely ruined by the use of crude or irregular figures. Great care must be used to make the figures well and of uniform size, and this part of the work should never be hurried. It will be well to check every figure by scale after the drawing is completed. Center lines are shown by dot and dash black lines, or full red lines, and usage differs regarding dimension and witness lines, but a dash black or a full red is the most common. Full red lines are preferable, as they show less strongly on a blue print, and a full line may be made more readily than one which is dotted. Dimension lines should be broken to allow space for the figure. Arrow or witness points should be made long, and at an angle of about 45 to 60 degrees, never wider, and the point of the witness mark should just touch the lines to which the dimension is given. The over-all dimension should be given where there is a series of subdimensions, to insure an additional check on the work. There are other important points regarding the figuring of drawings, which will be brought out from time to time as illustrations may arise. As stated above, the title should be placed in the lower right-hand corner of the sheet, and should designate the name of the whole, the special detail which may be represented, the scale, the date of completion, and the name of the designer, engineer or draftsman. Plain type should be used. The writer's experience goes to show that an Italic, Gothic letter entirely devoid of flourish is most readily handled by the largest number of draftsmen.

1 1/2x1 1/2x3/4 Reducing lee

Scale-Full Size

Nov 1. 1901.

E.T. Child.

SHEET PLAN (Reduced One-Third).