THE ALMY WATER TUBE BOILER. (FIG. 71.) Built by the Almy Water Tube Boiler Co., of Providence, R. I., is made of either steel or wrought iron tubes, having fittings of malleable iron of the best quality, specially for their use from their patterns. The internal arrangement is of tubes vertical on three sides, then at sufficient height tubes horizontal. This forms fire box, the grate surface of which occupies 75 per cent. of floor space of boiler, and representing about 1 square foot grate area as equal to 25 to 30 square feet of heating surface of boiler.

The great number of square feet within fire box, where all tubes exposed to radiant heat are of small diameter; the direct vertical flow of the products of combustion up between and around the horizontal tubes, the under sides of which always present a clear surface to the heat, enables this boiler to be an extra quick steaming one. Steemships, torpedo boats, yachts, or merchant steamers provided with the Almy water tube boiler, can have full head of steam from banked fire in 10 to 20 minutes.

The feed-water is received at either front or back of boiler into lower manifold, passing first through a heater provided for that purpose, separate from, but in connection with boiler proper, from whence it enters boiler at a high temperature. The flow of water in circulation is continuous in one direction. Before completing the

circuit the current of steam, containing water, enters the separator in front of boiler, which takes the form of an involute coil. Here the dry steam rises to top of separator where it is drawn off for engine power, and here, also, by the law of gravity, the water now freed from the lighter steam is returned to the circulation from the bottom of separator to lower manifolds on each side of fire box.

Repairs to this boiler are made under conditions of great convenience. A section of casing being unbolted, sections of boiler can be unscrewed, removed and replaced by any handy engineer or fireman. When necessary, any section can be blocked off at sea, with the same celerity that a tube in other boilers can be plugged.

Tube sections always obtainable at the works, or can be cut anywhere and replaced in fittings.

The sectional form of this boiler, though usually rectangular, enables a lengthening or a widening of shape, as certain spaces may require. They are built in sizes from 3 square feet grate area to 50 square feet grate area, with height in sizes from 15 to 50 square feet grate area, from 72 feet to 9 feet; while floor space for largest size of 50 square feet grate area requires but 8 feet square. The weight of the Almy patent water tube boiler, in the larger sizes, is about 400 pounds per square foot of

grate area and from 250 to 350 pounds per square foot grate area in smaller sizes.

These boilers are designed for 250 pounds per square inch steam pressure. They have been approved by the Board of Supervising Inspectors of the United States. There are numbers of them in use to-day in passenger steamers and steam yachts, resulting in economy in weight, space and fuel. These boilers are enclosed in sheet steel or iron casing, lined where necessary with firebrick and asbestos and throughout with asbestos. They are tested to 400 pounds hydrostatic pressure, and with all furnishings are delivered complete ready to place and unite to engine.

CHAPTER XXII.

REPAIRS AT SEA AND HOW TO MAKE THEM.

BREAKDOWNS at sea will happen, owing to structural weakness, bad design or workmanship, to the most careful and able engineers; and when they do occur the engineer in charge must then show what he really is, by the clear foresight and mechanical skill which will enable him to so repair damages that the ship can make some port in safety. Breakdowns happen at the most unexpected times and in the most unexpected places-sometimes from the ignorance or carelessness of the engineer on watch, and sometimes from causes over which he has no control. Accidents do not happen as per order, and this is the reason why no special rules can be given for the repair of all kinds of breakdowns a rule which would work admirably in some cases would not do at all in others. engineer should always be studying his engine, and by imagining some part breaking down, he can then calmly think over a plan of repair, so that if that part should give way, he would know at once what to do. No specific rules can be given by anybody for the thousand and one cases which may arise, but a general plan of

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