By E. A. Sterling.

Progress, Volume II, Issue 11, 2 September 1907, Page 409

By E. A. Sterling.

Machinery of special design has found extensive use in logging operations, particularly in the forests of North America. Logging railroads donkey engines, steam skidders, and wire rope systems of various kinds contribute to the ease and economy of getting logs to the mills The primary steps of felling the trees and sawing them into log lengths have, however, been done mainly by hand labour up to the present. Machine saws of practical value for cutting standing timber have never been perfected, largely because the necessary power has not been available, and aho on account of the danger and difficulty of handling a machine of any kind in rough forest land. The same is true in the main of sawing the felled timber into standard logs. An exception to the latter is found on the lands of the McCloud River Lumber Company in Siskiyou County, California, where a compressed air " buckingup " saw has been successfully used for some years. The trees are felled by hand, and cut

into log lengths by the machine saw. The company operates on comparatively level land near the base of Mount Shasta, wh^re the forest of yellow pine, sugar pine, and white fir is composed of unusually large individual trees in open stands. The ground cover is a rather dense chaparral. The machine consists of a traction engine equipped with an air compressor and a storage tank. To the air tank are attached rubber hose which give a working radius of 300 feet. The saws, which are similar to a heavy cross-cut saw, are actuated by a piston working in a small cylinder set in a movable frame, which can readily be attached to logs of any diameter. The cylinder, which has pivot trunnions removably hung in bearings, is connected with the compressed air tank by a line of hose. The usual outfit consists of three frames and one saw. The saw when started is left to work automatically, while the two empty frames are being moved to new cuts and attached to receive the saw. A " swamping" crew precedes the compressed-air saw and trims the felled trees, throwing the brush to one side to give room for the machines. The traction engine is moved under its own power to convenient points, where several trees are.

Sir Benjamin Baker died on May 19th at Pangbourne, Berkshire, England. He was born in 1840, and was undoubtedly one of the greatest engineers of the world. The two engineering works by which he will be best remembered are the Forth Bridge in Scotland, and the Assouan Dam. Eiffel, the French engineer, declared the former " the greatest construction in the world." It is 2,765 yards long and cost £3,000,000. It is built on the cantilever principle and its main spans are each 100 feet longer than the main span of the Brooklyn Bridge. Its steel towers, 360 feet high, give 151 feet headway above the Forth at high water. The Assouan Dam also cost about £3,000, 000. It is a mile and a quarter long and raises the level of the Nile sixty-seven feet. The dam is 120 feet high and varies in thickness from 82 to 26 feet. Behind it is a lake of 140 square miles, storing water sufficient to ensure the irrigation of the Delta in the dryest season. For his work as constructing engineer of this great work Sir Benjamin received from the Sultan the First Class of the Order of the Medjidie. He had already been made a Knight of the Order of the Bath and of St. Michael and St. George. He received several honorary degrees from the leading universities of Great Britain, and was a fellow of the Royal Society.

The growing popularity of interlocking rubber tiling is shown by its invasion of new fields, being extensively used in kitchens, vestibules, and bath-rooms of the better sort : in fine ocean liners, lake steamers, ferryboats, and yachts, where its non-slippery character and the fact that it remains unaffected. by constant -wrenching strains render it very valuable, and now it may be seen in one of the finest cathedrals in the country, and in one of the largest of our public art galleiies.