Course of light in telescope from star to focus
For direct photography or visual observations at the focus of the 72-inch mirror, the reflected cone of star light from the mirror B, is intercepted by a plane mirror also silvered on the front surface, 19·5 inches diameter and 3·25 inches thick placed at 45°. This form of reflecting telescope was first used by Newton, hence the name. The focus is then formed, as shown, at the side of the tube, and if a plate is placed there and accurately guided by small eyepieces with cross wires, photographs of any desired small region in the sky can be obtained, or visual observations may be made. The oculars can easily be reached from the observing platform for any position of the telescope.
The Dominion Astrophysical Observatory - from the south
Horse-boat at Empy’s Ferry, Osnabruck, Ontario
Paddle-wheels for driving boats through the water were used long before steam-engines were thought of. They were worked by hand and foot-power without, however, any advantage over the old-fashioned oar. The horse-boat, in a variety of forms, has been in use for many years, and is not yet quite obsolete. In its earlier form two horses, one on each side of a decked scow, were hitched to firmly braced upright posts at which they tugged for all they were worth without ever advancing beyond their noses, but communicating motion to the paddle-wheels by the movable platform on which they trod. For larger boats four or five horses were harnessed to horizontal bars converging towards the centre, and moved around the deck in a circle, the paddles receiving their impulse through a set of cog-wheels.
C. P. R. grain elevator at Fort William, Ontario
The farmer sells his crop of wheat to the grain-dealer, and carts it, say, to Brandon, where the purchaser takes delivery of it at his elevator. Let us examine this thing somewhat minutely, taking by way of illustration one of the elevators belonging to the Canadian Pacific Railway Company at Montreal. It is a medium-sized one, having capacity for storing about 600,000 bushels of grain. The same company’s elevators at Fort William and Port Arthur are much larger, having capacity for 1,500,000 bushels. In Chicago and Buffalo there are elevators of three millions of bushels capacity; but, whether larger or smaller, in their main features they are all alike. The elevator is a wooden structure of great strength. Its massive stone foundations rest on piles imbedded in concrete. The framework is so thoroughly braced and bolted together as to give it the rigidity of a solid cube, enabling it to resist the enormous pressure to which it is subjected when filled with 18,000 tons of wheat. The building is 210 feet long, 80 feet wide, and 142 feet in height from basement to the peak of the roof. Including the steam-engine (built at the C. P. R. works) of 240 horse-power, the entire cost of this elevator was $150,000. It consists of three distinct compartments—for receiving, storing, and delivering grain. On the ground floor are two lines of rails by which the cars have ingress and egress. The general appearance of this flat is that of a bewildering array of ponderous posts and beams, shafting, cog-wheels, pulleys and belts, blocks and tackle, chutes, and the windlasses for hauling in and out the cars, for a locomotive with its dangerous sparks may not cross the threshold. Beneath this, in the basement, are the receiving tanks, thirty-five feet apart from centre to centre, corresponding to the length of the cars. Of these there are nine, enabling that number of cars to be simultaneously unloaded. This is quickly done by a shovel worked by machinery, with the aid of two men, the grain falling through an iron grating in the floor into the tank. The elevator has nine “legs.” The leg is an upright box, 12 inches by 24 inches, extending from the bottom of the tank to the top of the building; inside of it is a revolving belt with buckets attached 15½ inches apart. The belt is 256 feet long, and as it makes 36 revolutions per minute, each bucket containing one-third of a bushel, each leg is able to raise 5,250 bushels per hour. A car is unloaded and its contents hoisted into the upper regions in fifteen minutes. When all the legs are at work 30,000 bushels are handled in an hour.