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Side View

Front View

FIG. 48.

Drawing Showing Urinals in Two Different Positions.

scale on which plans are illustrated is too small to work easily.

In drawing the front view of the urina it will be noticed, by the way, that the fixture is in such a position that the waste is carried directly back. In this case, we might have dotted the waste to the floor, and the back air to the partition, but have preferred to show it in the way that it appears, which we believe will be clear enough for all purposes. There are many places where it is necessary to show part of the work by dotted lines, the dotted lines, of course, always signifying that the work thus shown is behind a wall or other obstruction, but the writer's opinion has always been that in this line of work, dotted lines do not add to the appearance of a drawing, and that it is better not to show them, unless the drawing will be made less clear by omitting them. Up to the present point we have confined ourselves entirely to lead and cast iron work. If we are to be able, however, to draw different kinds of work as it is presented to us, we shall need to know how to show wrought iron piping, not only on supply work, but on back airing. After what instruction has been given on cast iron work, there is not a great deal additional to be given on wrought iron. In Fig. 51, we give two methods of showing fittings, and also the two positions in which valves are usually seen. A side view of the valve shows its true shape, while in an end view the wheel handle and body represent it. In Fig. 52 is also given a sketch showing errors likely to be made, such as giving too wide a sweep to the curve of an elbow, and in making tee branches too long. A glance at the fittings themselves will show wherein the errors mentioned exist. As to a choice between the use of the beaded fittings and the plain fittings, we believe the former will be found the easiest to draw. The reason for this is that the diameter of the fittings and the diameter of the pipe are usually made the same, while the plain fittings to show as fittings, must have a greater diameter than that of the pipe. and this difference between the laying out of the two styles of fittings means less work on the beaded style.

For this reason, the writer usually pre

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fers to use this fitting in the drawing of work in which water pipe is to be drawn,

FIG. 52.

Sketch Showing Errors Likely to be Made. but in the case of wrought iron back air work, is inclined to use the plain fitting, as shown in Fig. 53, in which is represented back airing, including the main and the several branches. It will be noticed that fittings are shown in several different positions. For instance, the

branch taken off the main back air where it offsets, comes out of the tee straight toward us, and then bends off at an angle of 45 deg., then comes out straight toward us again, and then runs horizontally. The bends used on this branch are in such a position that their true shape cannot be seen. If the beginner has difficulty at any time in seeing how different fittings appear when placed in certain positions, let him take the fittings themselves and place them before him in such positions as are required. In doing this, however, he must remember to draw whatever object he has before him, with the element of perspective entirely eliminated. We have referred to this before, but a cautionary word at this point will not be out of place. It will be noticed that all the fittings of Fig. 53, whether wrought iron or cast iron, are drawn with their ends square across, and not curved as they would usually appear in perspective. Occasionally a part of the work will have to be shown in such a way, that a certain amount of perspective will have to be used, but for one unpracticed in its execution, it is a difficult matter to make such work look well, and errors on such work are very likely to destroy the appearance of an otherwise excellent drawing. We are ready now, we believe, to take up complete elevations of different work, including both drainage and supply, and this we shall do in the next chapter.

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CHAPTER X

HILE it must be clear to our readers that the ability to make a good, clear pencil drawing is the chief point to be gained in pursuing a task of this kind, the ability to ink the drawings is also very desirable. We presume that many of those interested will care only for the pencil work, but others on the contrary will be anxious to go further and take up inking. Inking adds character to a drawing, and makes the work much clearer than pencil can. other point is this-if the drawing is of any extent, by the time the pencilling has been completed, even though a hard pencil has been used on the work, the sheet has become much soiled by constant rubbing over it of the hands, sleeves, the square and triangles, etc.

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Now if the drawing is inked, the whole surface can be gone over with a soft sponge rubber, which will not rub off the inked lines, and the sheet made perfectly clean, or better still, a piece of transparent paper, such as thin bond paper, can be laid over the original pencil drawing and traced off onto the clean sheet. No doubt those who are pursuing this series have long before this discovered that it is almost impossible to keep the sheet clean, and ofttimes the smut has made what would otherwise be a good piece of work, look rather dubious. This is to be expected, and is more or less the experience of skilled draughtsmen. One suggestion would be, as far as possible, to complete the work at the top of the sheet first, then that next lower down, etc. This will save rubbing over finished parts of the drawing.

Another point is to see that the square

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square. No. 2 is called a bow pen, and is used in making small and medium sized circles. No. 3 is an attachment used in inking large circles. As shown, it is made with a joint and is designed to slip into the large compasses shown in our first chapter, taking the place of the pen cil attachment. Each of these three instruments is usually to be found in the ordinary set of drawing instruments.

The bow pen and ruling pen are used constantly, and are absolutely necessary, while the attachment (No. 3) is made less use of. Common writing ink is not suitable for drawing purposes, an India ink being necessary. The ink usually comes in such a bottle as shown in No. 1 in Fig. 55. It will be observed that the stopper to the bottle is provided with a quill, which dips down into the ink. No. 2 in Fig. 55 will serve to illustrate the manner in which the inking instruments are filled with ink. The quill, which holds quite an amount of the ink, is touched lightly to the instrument, between the two nibs, and the ink at once flows from the quill and supplies the instrument, as the illustration shows.

It is best not to fill the instrument too full, usually not more than half as full as No. 2 indicates, for it is liable to flow too rapidly from the pen, and cause bad work. It will be readily understood that the size of the line is regulated by the little thumbscrew with which each instrument is supplied. By screwing the nibs close together a fine line is made, and a coarse one by releasing them. By the way, to those who have never had any experience in inking, a word of advice as to the making of lines will be of benefit. The beginner, nine times out of ten, endeavors to make his lines as fine as possible. This the experienced draughtsman does not do. In the first place, the instruments do not work as well on fine lines. Then again, the drawing is not so clear, and in erasing, the fine lies are more liable to be partly rubbed out. If an illustration is to be made from the drawing, a good, heavy line is preferable, and if blue prints are to be taken from the drawing, light lines are apt to appear dim on the print, especially if over-exposed. Therefore, do

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