2. Question.—Supposing there are boilers working on each side of the one you got steam up in, how would you act?
Answer.—I would light the fire by putting in a few shovelfuls of live coal from one of them instead of using firewood; that is all the difference I would make.
3. Question.—What is the cause of the rapid motion of the water in the gauge-glass at times? Is that motion general throughout the boiler?
Answer.—No; air enters the boiler with the feed-water, and the gauge-glass tube being in the vicinity of the incoming water, some of the air enters the glass and flies up rapidly through the top cock and into the boiler again; in fact there is very little motion of the water in the boiler at any time while working. I have proved this to be so, and in this manner: the boiler cleaners having finished the cleaning, hurriedly scrambled out of the boiler and left several tools they had been using on the crown of the fire-box, namely, a bass hand brush, a tin can, and a tin candlestick, and a small iron pail; the manhole cover was put on and boiler filled and put to work before the things were thought of, and then it was too late and they had to remain there until the next cleaning time, which was thirteen weeks; and when the boiler was at last blown out and the manhole cover removed, the things were on the crown of the fire-box exactly as they were left three months previously. In order to satisfy myself of this, to me, extraordinary discovery, I placed several articles on the crown of the fire-box, things that could not stop up the blow-off pipe if they were swept off, and got up steam as usual, and after three months' hard steaming I blew out the water and steam, took off the manhole cover, and there were the things as I had left them thirteen weeks previously; of course they were all coated with fine mud, but no signs of having moved a hair's breadth.
4. Question.—But water in an open caldron with a fire under it, as in the steam boiler, will madly sweep the sides and bottom with terrific ebullition. How would you account for the great agitation in the open caldron while the steam boiler had hardly any, although both vessels had fierce fires under them?
Answer.—In the matter of the open caldron the action of the water has no resistance but that of the atmosphere, whereas in the steam boiler the movement of the water is resisted from the moment it is heated, for then a vapour rises above it, and, as the heat increases, the resistance to the movement of the water is proportionally increased, and as the heat of the steam increases the pressure on the water increases proportionally all through, the steam being above the water. Any old stoker knows that when getting steam up in a boiler the lower parts are often only warm when there may be eight or ten lb. on the square inch in the upper portions; when the water begins to boil the steam rises in the form of minute globular particles, and remains above the water until there is an outlet for it by opening the stop-valve or through the safety-valve; and as the pressure is the same throughout every part, nook and corner, and angle, there can be no dominating force to cause any agitation within the boiler.
5. Question.—What is superheated steam, and why is it used?
Answer.—If a boiler is placed at a long distance from the engine or whatever the steam may be used for, there is much or little condensation according to the distance and the weather, so that there would always be water mixing with the steam, and that is most objectionable where a steam engine is concerned, and by super-heating the steam it comes to the engine as hot and dry as if the boiler were close by; but whatever the heat of the steam may be, the pressure cannot be increased after the steam has left the boiler. In proportion to the pressure of steam so is the heat of it; the higher the pressure the hotter the steam.
6. Question.—If your water gauge-glass broke while the boiler was working, how would you proceed to rectify the mishap?
Answer.—By immediately shutting off both cocks, the water-cock first, then I would open the blow-out cock (at the bottom of the gauge-glass) and keep it open to the finish, and commence unscrewing the nuts, clearing them of any bits of india-rubber that adhered to them, also the sockets. Get one of the half dozen glasses already cut, and my string of rubber rings, enter two rings on the bottom end of the glass, slip the nut over them, slip two rings on the top part of the glass after having slipped the nut on, and enter the rings in the sockets, then screw up both top and bottom nuts by hand alternately, and when screwed up evenly, open the steam cock a shade to warm the glass, and when it is hot enough, open it more and commence closing the blow-out cock, by tapping it lightly by hand, then open the steam cock a little more and open the water cock a little also, and shut off the blow-out cock, and presently the water enters the glass, and both top and bottom cocks may now be opened to their full extent, and the job is done.