When the gauge shows 30 lbs. of steam you might start the model by turning on the cocks on cylinders until no more condensed steam issues from them. Then shut them off and turn on steam full power and watch the engine travel, gradually increasing its speed. CHAPTER VII. CONCLUSION. Let us now bear the conclusion of the whole matter, which takes us straight back to where we started, and we again repeat if you want to become an engineer make up your mind that you will be a good one or none at all. We have examined the locomotive inside and out, underneath and on top, even peering down the smoke-stack, crawling into the fire-box, and learning the true science of shoveling coal. What then remains to be told? Nothing that can be remembered long enough to be of any practical use. There are matters--dozens of them--connected with locomotive engineering which we have not even alluded to, but they are for the most part such as must be learned by actual every day experience to be of any use. We might, perhaps, under three heads speak a few closing words. First let us take up SIGNALS, and post ourselves a bit on that most important subject. The greater part of an engineer's time while on his engine must be spent in the lookout for signals. Upon this depends not only the safety of every soul on the train but his own as well. _Never jump at conclusions in the matter of signals._ Never assume that because a "distant" signal and all the other signals are off the line is clear. Every engineer should, as far as possible, not only see that each signal is off, but he should also cast his eye over the road in front of him to see whether it _should_ be off. At night caution in the matter of signals is even more necessary than in daylight. Then the only safety lies in keeping a constant lookout. You must know your road. It is not enough to know where the up grades lie and where the downs. You must know just how steep the grades are and their length. Often signals are badly placed and cannot be seen until the engine is close upon them. With this you have nothing to do. Engineers do not place signals. Doubtless if they did they would alter the position of many of them. All you have to do is to heed the signals, no matter how well or how badly they are placed. To enter into a detailed description of signals until some universal system of signaling is adopted, would be but a waste of time. You will have to learn all these things during your apprenticeship; they are matters upon which books can give you little help. Presence of mind you must always have if you expect to become a good engineer, and courage, too--plenty of it. This brings us to our second head, which we will write "BROKE DOWN." What to do when the engine has broken down? There comes the tug of war, the time when it will be definitely decided whether the engineer is good, bad or indifferent.