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MARINE REVIEW. 13 Eaves' Helical Induced Draught. Messrs. Sir J. Brown & Co., Sheffield, England, are now intro- ducing a further improvement on the Eaves' induced draft Serve tube system, with which they have been so long identified. By refer- ence to the accompanying illustration the new sytem will be easily un- derstood. The cold air for the combustion of the fuel enters from the back end of the boiler, passing along the outer space A and A' to the valves B and B' in the furnace fronts; on its way this cold air is guided round the outside of the inner space C in a helical direction by partitions set up as shown. After combustion the waste hot gases leaving the boiler pass through the smoke-box into the inner space C, and are made by similar partitions to pass round and in close contact with the boiler in a helical direction on their way to the suction fan. The boiler by these means is thoroughly enveloped in the escaping heat, effectually preventing either radiation, condensation or strain- ing of the boiler under any forced conditions, such as rapid generation of steam from cold water, or sudden and greatly increased evapora- tion. The cold air on its way to the valves also absorbs a large amount of heat from the escaping gases, and so enters the furnaces at a greatly increased temperature with resultant economy. No blocking up of the bottom boiler tubes through any deposit in the smoke-box can, it is claimed, take place, as such deposit, if any, drops to the bottom of inner casing C, from whence it is easily removed by doors at front. The doors D are-placed go as to allow of a brush being passed through, to sweep away any SOovy deposit from the boiler shell, should any such deposit take place. The manuTavtuxars report that very careful experiments have been made with this system, with results varying from 78 to 82 per cent. of efficiency, and a coal consumption of from 30 to 35 pounds per square foot of grate. The trials gave a boiler efficiency in one case of 82 per cent. and in the other 78 per cent. of the actual calorific value of the coal used. If we take the mean of these figures, namely, 80 per cent., and work out the evaporation on the basis of the best Welsh coal, we obtain the follow- ing results:--Heat units from complete combustion of 1 pound of best Welsh coal, 15,629; latent heat of evaporation from and at 212 degrees Fahrenheit, 966; caloric value of coal in pounds of water evaporated per pound of coal from and to 212 degrees Fahren- heit--15,629 966 value = 16.18 x 80 100 of 13 pounds of water per pound of coal from and at 212 degrees Fahrenheit, with a rate of combustion over 30 pounds of coal per square foot of grate, and with a ratio of heating surface to grate sur- face of only 28 to1. An ordinary marine boiler of the same dimen- sions as the one used in these trials, namely, 10 feet 6 inches diameter by 10 feet 6 inches long, will, with good natural draught, evaporate -- 16.18 pounds; 80 per cent. of the above calorific -- 12. 95 pounds; or practically an evaporation about 5,000 pounds of water per hour, the efficiency being about 65 per cent., or equal to 10.5 pounds of water evaporated per pound of best Welsh coal from and at 212 degrees Fahrenheit, instead of 13 pounds. The trial boiler has now been at work nine months, and ou examining the shell it was found to be free from any sooty deposit; in excellent condition, and no signs of corrosion or leakage visible. --The Engineer, London. Geipel Steam Trap. The Geipel steam trap, which is used largely by British ship builders, and which is fitted to the steamer Inchmona, whose record has received considerable attention -of late, is illustrated herewith. This trap is positive in its action, and it is stated that there is a distinct economy in steam gained by its use, and further that there is also an economy in packing. These things may be difficult to prove, but there is little doubt that leaky steam traps are responsible for considerable waste of steam. A celebrated foreign expert, Prof. Kennedy, has stated that in his trials they, the steam traps, required more looking after than the whole of the rest of the machinery put together. Tue action of the Geipel trap will be apparent to all engineers who study the illustration. The lower or brass pipe is connected to the steam pipe, the upper iron pipe forming the discharge. A very slight expansion in the brass pipe will cause the apex at which the valve is situated to rise a considerable distance; the valve spindle then butts against the lever, and there can be no passage of either steam or water until, by cooling down, the apex is caused to descend, and the valve can rise with freedom. When it is desired to blow through, the valve may be opened by hand by merely pressing down the lever. The valve may be readily examined by unscrewing the top. The trap is very suitable for fixing on the bed plates of engines, for which purpose many forms of steam traps are too bulky. The Central Marine Engineering Co. of West Hartlepool, a well-know ship building concern, is said to have used, within the last six months, upwards of 100 of these steam traps. The White Star Steamship Co. has them in use. The trap has very few working parts, and the merits claimed for it are well worthy of consideration by those having use for this sort of appli- ance. Itis manufactured by Thorpe, Platt & Co., No. 97 Cedar Street, New York. : Stocks of Grain at Lake Ports. The following hle, prepared from reports of the Chicago board of trade, shows the stocks Un haat and connec manne eee tors at the principal points of accumuia..__ anthe lave ieee aaa J) od 9 . Wheat, bus... Corn, bushels. Chichigoria cet eee occas tree 13,599,000 Dit a Dulath Fk eho oe 2,482,000 6,000 Milwatkees sos cigs ves ie eee 348,000 -- 8,000 Detroiti) 22.2755 ate eee ee 392,000 58,000 Toledo te Ae ee eee 1,135,000 167,000 Buffalo: oo bee 2,878,000 492,000 20,834,000 5,826,000 As compared with a week ago, the above figures show, at the sey- eral points named, an increase of 577,000 bushels of wheat and 236,000 bushels of corn. Solid through trains between Chicago, Buffalo and New York city, and through sleeping cars to Boston, constitute the through ser- vice of the Nickel Plate road. Rates always the lowest. 412Dec.31