slightly on his heels, first, toward the coal, and then toward the fire hole.

If a fireman, in the act of firing, lifts his feet off the foot plate, he will roll about, and the firing will be improperly done, in consequence of the coal being knocked off the shovel by the latter catching against the fire hole ring or depletion plate.

Don't jam the shovel into the fire-box—stop it dead at the fire-hole ring. Give the coals a fling, discharging them like shot right into their intended destination.

Don't jam your shovel into the coal and load it down as much as possible. A few lumps of coal lying nicely on the body of the shovel can be handled better. The shovel should not be pushed into the coal by the knees, but should be worked only by the muscles of the arm.

Throw the first shovelful of coal into the left hand front corner, the second shovelful in the right hand front corner, the third shovelful in the right hand back corner, the fourth shovelful in the left hand back corner, the fifth shovelful under the brick arch, close to the tube plate; the sixth and last shovelful under the door. To land this one properly the shovel must enter the fire-box and should be turned over sharp to prevent the coals falling in the center of the grate or the fire.

Now comes the question when to fire.

To fire properly, with the greatest effect in saving fuel, it should be done as soon as the steam begins to lift the valves, when by opening the fire-door and putting on a small quantity of coal the steam is checked sufficiently to prevent its being wasted by blowing off.

Some engineers have an idea that unless the steam blows off furiously they have not done their duty by the engine.

A big mistake this.

When steam, water and fuel are being thrown away through the safety valves, it is a positive proof of the existence of either one or the other of the following evils:

Either the engine is too small for its work or too great for its man, and both the engine and the man would do better on short runs; the former until it could be doctored, or the latter until he had learned to bottle his noise.

The intervals between the rounds of firing, which should consist of six shovelfuls only each time the door is opened, is in every case regulated by the weight of the train or load, the state of the weather and the time allowed for running the trip, together with the quality of coal.

The greatest possible mistake on an engine is putting on too much coal. The fire is choked, clinkers are formed, the temperature of the boiler is reduced, contraction and expansion sets in and leaks are formed—in a word everything goes wrong.

The secret of good firing is to fire frequently, a little at a time.

Feeding.

Having discussed fire, let us now consider the other element upon which the locomotive lives—water.

The maintainance of steam in proper shape requires a knowledge of how and when to feed.

The aim in feeding should be to regulate, as nearly as possible, the supply to the demand—just sufficient to keep the water at a proper level in the glass.

This keeps up an even temperature in the boiler plates, tubes and fire-box, and this has much to do with the service of an engine. Many engineers always work their feed in the precise way to get the worst results.

As soon as the boiler is full of steam and blowing off they turn on the pump full and keep it on until the steam is from 30 to 50 pounds below the maximum pressure before turning it off.

This method is the very worst possible. What is wanted is a constant moderate supply of water, keeping the pressure as nearly even as possible. Nothing can beat this.

When injectors are used one of them should be screwed down so that it will act moderately like a pump. This will save the water which is usually lost in turning injector on and off.

On the Foot-plate.

When the train is under full headway the engineer should stand in his proper place on the foot-plate so as to be able to command the regulator and reversing valve at an instant's notice.

Especially is this necessary at night, when the engineer's attention should always be on his engine, listening constantly to its beats to detect any irregularity which may arise from some defect in the machinery, frequently casting his eyes on the pressure gauge, and on the level of the water in the gauge glass.

When the fireman puts on coal, the engineer should look round occasionally, to be sure that he is doing it right, placing the coal next to the walls of the fire-box, and not piling them in a heap in the middle.

When the rails are slippery, great care is required to prevent the engine from slipping, by closing the regulator in time.

When about to enter a tunnel, the sand valves should be opened, and the sand allowed to flow freely until the train emerges from the tunnel—sand is cheaper than steam.

Never forget that lives and property depend upon the faithful performance of your work.

CHAPTER VI.

HOW TO BUILD A MODEL LOCOMOTIVE.

As a preparatory step toward becoming an engineer, it is highly desirable for the boy who looks forward to that honorable calling to familiarize himself with the different parts of the locomotive engine. This we have stated before.

There is no better way to accomplish it than to build a model locomotive.

At first glance this may seem to be among the things impossible, but it is not so, providing the boy has a mechanical turn, and any boy who has not better not think of becoming an engineer.

We now propose to give simple and accurate directions for building a model locomotive, accompanying the same with a series of illustrations, which we trust will be sufficient for the purpose intended.

Before beginning we have one word of caution to offer.

Don't do your work in a hurry. Don't calculate on the length of time it is going to take you to do it. Make up your mind to understand each detail before you begin, and to work slowly and carefully.

If you remember this you will probably be able to build your locomotive. If you forget it you certainly will fail.

How to Begin.

First of all in building a model locomotive, as in every other class of engineering work, it is necessary to get the measurements correct in spacing out the different parts to be joined together; and do not think that because it is only a model you are making that any off-hand way will do, because you will find before the engine is half finished that great accuracy is necessary if you wish your model to work.

A slight mistake in the measurements of a large engine will cause so much friction as to take half its power to overcome. The same mistake with your model will stop it entirely.

In soldering be careful to get the metal thoroughly heated. You will then get a firm joint—otherwise not.

Fig. 1.	Fig. 3.