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the storage of the material used in the shops above. The equipment of the gas engine laboratory comprises a 35-H. P. three-cylinder verticle gas engine built by the Westinghouse Machine Company, a Fairbanks, Morse & Co. 7H. P. gas engine, a Rider-Ericsson hot air engine, a new Mahler-Baum calorimeter, a Junker calorimeter, a large meter for measuring air, a motor and blower to deliver air at atmospheric pressure, a two-stage air compressor, and various calorimeters for determining the heat values of fuels. On the first floor of the new building is located the Forge Shop, the equipment of which includes thirty down-draft forges, a 200-pound steam hammer, and a power hammer, a coke furnace, a 20-inch drill press, and a 15-inch double emery grinder. A jib

The Foundry is piaced on the top floor, principally for the reasons of providing for the quick removal of gases and smoke, to avoid the heat that would result from its being placed below other rooms, and to secure the overhead light. It is provided with a Whiting cupola, a set of forced-draft brass furnaces, and a portable core oven. There are three one-ton cranes running through the foundry, with a 5-inch air hoist on each. The equipment also includes three moulding machines and a pneumatic sand sifter. A system of tracks is arranged to carry the metal on trucks from the cupola to the moulds in different parts of the foundry. The demonstration rooms are a special feature of the building. There is one room on each floor with a seating capacity of about forty students, and in each room there is the type of machine to demonstrate how the particular work of that shop is to be done. Ample provision is also made on each floor for lockers and lavatories.

The shops are used by the students of all engineering courses, and by the evening classes four evenings each week. The shop courses are very popular with the students of the evening classes, and the enlargement of the scope of the Institute to include these courses in its curriculum marks one of the most important epochs in its history. No student who applies for admission to the Armour Institute of Technology need be turned away on account of lack of preparation. If he is insufficiently prepared to enter the College of Engineering, he can get this preparation in the Scientific Academy, or, if he is employed during the day, he can avail himself of the opportunities of the evening classes. Should it happen that he lives too far away to take advantage of any of these courses, he can obtain his preparatory requirements in the American School of Correspondence.

The careful working out of these broad plans for the purpose of giving young men an opportunity to secure a technical education, is due to their steadfast friend, President Frank W. Gunsaulus, who, in co-operation with the trustees and faculty, leaves nothing undone to help every aspiring and earnest student to the realization of his plans

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crane is arranged to serve both hammers with the heavy work. At one side of the Forge Shop are seven benches with complete equipment for pipe fitting. The Machine Shop occupies the second floor, and is equipped with thirteen engine lathes, three speed lathes, B. and S. universal grinder, a B. and S. cutter, a B. and S. cutter and reamer grinder, and a Diamond grinder. There are three milling machines, a screw machine, a 30-inch planer, two shapers, a horizontal boring machine, a twist-drill grinder, a lathecenter grinder and several drill presses. At one end of the shop are thirty bench vises, with complete sets of tools.

In the Carpentry and Pattern-making Shop on the third floor are thirty-three 12-inch wood lathes, an 8-inch pattern lathe, four 6-inch pattern lathes, a circular saw, two band saws, a 26-inch surfacer, vertical boring machine, a threeside 4-inch moulder, scroll saw, and gluing bench. The shop is also equipped with forty benches, with vises and com

SHADE LINES ON DRAWINGS

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To make drawings easier to read, the shade lines come on the upper and

and to make the parts of the ob left-hand sides of the hole, since these ject stand out more clearly, shade lines are the lower and right-hand edges

lines are often used. The gen of the material which surrounds the eral principle which determines what hole. lines shall be shade lines is the same Fig. 3 is a plan and side view of a recas that which governs shade lines in orth tangular prism with one corner rounded, ographic projection. If, however, this and with a cylinder resting on it. Here theoretical principle were to be followed the lines A B and C D are not shaded, out exactly on drawings of machines and other complicated objects, it would involve a great deal of time and labor. Consequently, most draftsmen place shade lines on all lines which represent lower and right-hand edges.

The contour lines of cylinders, cones and other rounded surfaces should not be

FIG. 2. shade lines, although some draftsmen

since they are the contour lines of curved surfaces. In the plan view, the lower right-hand part of the circle, between X and Y, is shaded. To find these points X and Y, draw two lines tangent to the circle and making an angle of 45° with

PLAN

SIDE VIEW

х

А

BI

ELEVATION

FIG. 3.

FIG. 1.

the T-square line ; X and Y are the points shade them. If the cylinder is drawn in where the arrows are tangent to the cross-section, however, the edge should circle. be shaded, as the intersection of the plane Fig. 4 is a plan, elevation, and crossand cylindrical surface is a sharp edge. section of a cylinder. Here, in the plan,

All views are shaded alike, and both the larger circle is shaded on the lower are shaded as though they were eleva side, and the circle which represents the tions. The ray of light is supposed to come over the left shoulder of the draftsman as he faces the paper, at such an angle that the projection of the ray of light on the drawing paper is in the direction of the arrow in Fig. 1.

Figs. I to 8 show some of the most common shapes met with in drawings, and illustrate how the shade lines are placed on each. Fig. 1 is an elevation, plan, and side view of a rectangular

S prism with a smaller one resting on top

FIG. 4. of it. Fig. 2 is a plan and side view of a hole is shaded on the upper side. The rectangular prism with a rectangular points where the shade begins are deterhole through it. It is to be noticed that mined as explained for Fig. 3. The lines

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THE steam end of a duplex direct bearing surfaces between the ports. The

acting steam pump is very simi two outer ports admit steam to the lar to the cylinder of an ordinary cylinder, and the two inner ports are used

plain slide-valve engine. The only for exhaust. chief differences are: The valve has no In the steam engine, the piston is prelaps, and there are four ports instead of vented from striking the head, by the two. The four ports shorten the valve turning of the crank pin. A cushion of travel without reducing the width of the steam is obtained by the use of the

exhaust lap, which, by closing the port the piston makes a much longer stroke. before the end of the stroke, imprisons By regulating the cushion valve, the the steam, and the moving piston com length of the stroke may be varied conpresses it. The direct-acting pump has siderably. no crank, and the valves have no exhaust lap. The cushion is obtained at each end of the cylinder by the use of a small valve coded app00000 which puts the exhaust port in communication with the steam port. Let us consider the action of the cushion valves to be as represented in the accompanying diagrams.

In Fig. 1, the cushion valves are closed.

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FIG. 1. The exhaust steam flows through the exhaust port A to the exhaust cavity C, and escapes to the exhaust pipe. This continues until the piston passes port A. The steam now in front of the piston cannot escape, and is compressed in space B and the port, thus stopping the piston before the end of the stroke.

When the cushion valve is open, as shown in Fig. 2, the exhaust steam continues to escape after the piston has passed port A, by flowing from the steam port through the by-pass as indicated by the arrow. As nearly all the steam thus escapes, there is but little cushion and

FIG. 3.

struction is more nearly like that shown in Fig. 3, which represents the ports, valves, etc.

The latest type of British submarine lutions, the submergence usually boat, built by Messrs. Vickers Sons & lasts three hours; but quarters are Maxim, has a speed under water of be very cramped and the crew is obliged to tween nine and ten knots. It is a modi- keep fixed stations, as the displacement fied development of the Holland type, of the center of gravity might cause the the length of the new boats being 150 boat to take a disastrously deep plunge. feet (it was 120 feet in the original). It has been suggested that three sets of The radius of action in the new type these boats should be provided, each of is 500 miles (in the Holland it was which would have three days on duty and about 300 miles). The weight is too six days off, in order to preserve the great to permit the boats to be car-' health of the crew. The results of offiried on shipboard. In practice evo cial tests will be watched with interest.

SULPHATING OF STORAGE

BATTERIES

ITS CAUSE AND REMEDY

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NE of the most serious troubles (e) A short circuit may cause "sulwhich occur in storage batteries phating" because the cell becomes disis sulphating. This can usually charged (on open circuit), and when

be avoided or cured by proper charging it receives only a low charge treatment if it has not gone too far. compared with the other cells of the

The normal chemical reaction which series. A battery may become overoccurs in storage batteries is supposed discharged or remain discharged a long to produce lead sulphate (PbSO,) on time on account of leakage of current both plates when they are discharged, due to defective insulation of the cells their color being usually light brown and or circuit; or the plates may become gray, due to presence of the PbO, still short-circuited by particles of the active on the positive plate. But under certain or foreign substances falling between circumstances a whitish scale forms on them. the plates, probably consisting of Pb, Sulphating may be removed by careSO, Plates thus coated are said to be fully scraping the plates. The faulty “sulphated.” This term is, therefore, cells should then be charged at a low somewhat ambiguous, since the forma rate (about one-half normal) for a long tion of a certain proportion of ordinary period. In this way, by fully charging lead sulphate (PbSO,) is perfectly legiti and only partially discharging the cells mate; but the word has acquired a spe for a number of times, the unhealthy cial significance in this connection. sulphate is gradually eliminated. When

A plate is inactive, and practically the cells are only slightly sulphated, the incapable of being charged, when it is latter treatment is sufficient without covered with this white coating or sul scraping: when the cells are very badly phate, as it is a non-conductor.

sulphated, the charge should be at about The conditions under which this

one-quarter the normal rate for three objectionable sulphating is likely to occur days. are as follows:

Adding to the electrolyte a small quan(a) A storage battery may be over tity of sodium sulphate or carbonate, discharged, that is, run below the limits which latter is immediately converted of voltage specified, and left in that into sodium sulphate, tends to hasten the condition for several hours.

cure of sulphated plates by decomposing (b) A storage battery may be left or dissolving the unhealthy sulphate. discharged for some time, even though This is not often used in practice, as a the limits have not been exceeded.

cell must be emptied, thoroughly washed, (c) The electrolyte may be

too and fresh electrolyte added after the strong.

plates have been restored to their proper (d) The electrolyte may be too hot condition, before the cell can be used to (above 125° F).

advantage.

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