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30 out is the usual Hayward, of the latest type, known as the 1908 Class "i bucket. Although huge, and _ the amount of coal carried enormous, the power required to operate the bridge is comparatively small, due to the fact that the bucket is balanced by coun- terweights. When wide open the jaws of the bucket cover an area of 98 sq. ft., and its extreme height is nearly 13 ft. When closed it is so compact that it occupies a space of only 7 ft. in width, 10 ft. 6 in. in length and 11 ft. in height. The shells are built entirely of flanged steel plates, having the cutting edges protected by a con- tinuous steel shoe cut from solid steel plate. The arms and all other parts of the bucket are of forged or plate steel, with the exception of the upper center and power wheels. The mas- sive steel pin connections are entirely protected from wear by bushings of bronze, all bushings and journals throughout being of this material, which can be easily replaced. The closing mechanism consists of the usual Hayward power wheel and side chains device, an interesting fea- ture of which is the arrangement of the chains so that they do not wrap up on themselves when the bucket is closing. Each wrap of the chain lies directly on the hub 'of the wheel, thus ensuring constant leverage at all times. The wire ropes used for operating the bucket, of which there are four, receive little or no wear in the wheel, the holding lines 'being dead-ended on the top of the bucket and the closing lines wound on au un- usually large power wheel. It is im- possible for the closing ropes to es- cape from the power wheel score, a rope guard being provided which ef- fectually holds the rope at the bottom of the score in the wheel at all times. A noticeable feature in the bucket is the style of bracing, which is so ar- ranged that it is impossible for the Shells of other parts to get out of alignment, and the proportion is such that the wearing qualities are not sac- rificed at any point by the tremendous Sstreneta of structure, and digging power. The increased demand for Bird- _Archer boiler compound has_necessi- tated appointing the following repre- sentatives: Chicago, the Golden Rule Oil Co., 171 Washington street, Chi- cago; Baltimore, the Maryland Rail- way & Electric Supply Co., 604 Con- tinental building, Baltimore, Md. The Philadelphia office of the Bird-Archer Co. has been removed from 56 North Delaware avenue to 119 South Fourth street, room, 511. power THE Marine REVIEW TURBINE FANS FOR USE ABOARD SHIP. Afloat, as well as ashore, the tur- bine type of fan is steadily displacing the older designs. The fans or blow- ers that are now used in the United States; British, German and other lead- ing navies, and on the principal ships of the White Star, Cunard, Hamburg- American, American, French and many would have a wheel 60 in. in diameter, and, with casing, would occupy 320 cu. ft. of space, and weigh 2,000 lbs. A "Sirocco" turbine blower having the same output would occupy only 140 cu. ft. and weigh but 1,300 lbs. This shows a saving of 56 per cent in space and 35 per cent in weight. For forced draft these centrifugal fans have the same advantages as they | STROCCO VENTILATING FAN ON ALLAN LINER VIRGINIA. other lines, must have features that strongly recommend them. Aboard 'ship, perhaps even more than ashore, the unusually large volumetric output of "Sirocco" centrifugal fans, relative to their diameter and speed of revo- lution, had led to their universal adop- tion, owing to the fact that they can be used in confined. spaces where it would be impracticable to install an ordinary centrifugal fan large enough for the required duty. Roughly speak- ing, the saving in space is 50 per cent. To put the matter concretely, an or- dinary paddle wheel fan for an output of 20,000 cu. ft. of air per minute have for ventilation and other pur- poses. One of the accompanying il- lustrations shows this type of blower installed on the U. S. N. tugboats Pa- tapsco and Patuxent, the unique con- struction being a noticeable feature. The capacity of this blower is 700 cu. ft. against 1%4-in. water gage at 1,800 RP. M., 0.22 H..P.. The theory: of this construction is so entirely at vari- ance with the ideas that prevailed up . to the time of S. C. Davidson's inven- tion, that an outline of the principles of design followed in the "Sirocco" runner is of interest, In centrifugal fans of the ordinary