Tracts on Hydraulics

Forside
Thomas Tredgold
F. & F.N. Spon, 1862 - 219 sider

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Side 18 - That the virtual or effective head being the same, the effect will be nearly as the quantity of water expended.
Side 39 - However, as every thing has its limits, so has this: for thus much is desirable, that the water should have somewhat greater velocity than the circumference of the wheel, in coming thereon ; otherwise the wheel will not only be retarded by the buckets striking the water, but thereby dashing a part of it over, so much of the power is lost...
Side 61 - ... 2. The load at the maximum is nearly but somewhat less than, as the square of the velocity of the wind, the shape and position of the sails being the same.
Side 45 - ... which is equal to the difference of level between the surface of the water in the...
Side 34 - ... inches, and there impinging upon another body, would be capable of producing an equal effect by collision, as if the same cubic inch had descended through the same space with a slower motion, and produced its effects gradually ; for, in both cases, gravity acts upon an equal quantity of matter, through an equal space...
Side 41 - Experience confirms that this velocity of 3 feet in a second is applicable to the highest overshot wheels as well as the lowest ; and all other parts of the work being properly adapted thereto, will produce very nearly the greatest effect possible. However, this also is certain, from experience, that high wheels may deviate farther from this rule, before they will lose their power, by a given aliquot part of the whole, than low ones can be admitted to do : for a wheel of 24 feet high may move at...
Side 57 - a broader sail requires a greater angle ; and that when the sail is broader at the extremity, than near the centre, this shape is more advantageous than that of a parallelogram.* Many have imagined, that the more sail the greater the advantage, and have therefore proposed to fill up the whole area: and hy making each sail a sector of an ellipsis, according to M.
Side 47 - In trying experiments on wind mill sails, the wind itself is too uncertain to answer the purpose; we must have recourse to an artificial wind. This may be done two ways ; either by causing the air to move against the machine, or the machine to move against the air.
Side 8 - ... multiplied by the height to which the weight can be raised in the time given, the product will be equal to the effect of that power ; and the proportion of the two products will be the proportion of the power to the effect : so that by loading the wheel with different weights successively, we shall be able to determine at what particular load and velocity of the wheel the effect is a maximum.
Side 41 - ... paribus, as the motion is slower, the buckets must be made larger, and the wheel being more loaded with water, the stress upon every part of the work will be increased in proportion. The best velocity for practice, therefore, will...

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