TABLE

Containing the Quantities of Water, in cubic feet, that will be dis charged over a Weir per minute, for every inch in its breadth, when the depths of the Water from the surface to the top edge of the wasteboard do not exceed eighteen inches.

Cubic feet per
minute, according
-to experiments
made in Scotland.

Alloys. 1

TABLE

Showing the estimated Power of Man or Horse as applied to

Machinery.

TABLE

Of the Speed and Force of Wind, at different velocities.

Note.--The following rule is used to find the force of wind acting perpendicularly upon a surface-Multiply the surface in feet by the square of the velocity in feet and the product by 002288. The result is the force in pounds avoirdupois.

TABLE showing the Height of the Boiling Point, Fah., at different Heights of the Barometer.

In a vacuum water boils at 98° to 100°, according as the vacuum

is more or less perfect.

TABLE

Of the sizes of Nuts, equal in strength to their Bolts.

Note. The depth of the head should equal the diameter of the bolt; the depth of the nut should exceed it, in the proportion of 9 or 10 to 8.

TABLE

Of the Ratios of the Successive Hardnesses of Bodies.

Ductility and Malleability of Metals.

Ductility is the property of being drawn out in length without breaking. This property is possessed in a pre-eminent degree by gold and silver, as also by many other metals, by glass in the liquid state, and by many semi-fluid resinous and gummy substances. The spider and the silkworm exhibit the finest natural exercise of ductility, upon the peculiar viscid secretions from which they spin their threads. When a body can be readily extended in all directions under the hammer it is said to be malleable; and when into fillets, under the rolling press, it is said to be laminable.

There appears, therefore, to be a real difference between ductility and malleability; for the metals which draw into the finest wire are not those which afford the thinnest leaves under the hammer, or in the rolling press. Of this fact iron affords a good illustration. Among the metals permanent in the air seventeen are ductile and sixteen are brittle. But the most ductile cannot be wire-drawn or laminated to any considerable extent without being annealed from time to time during the progress of the extension, or rather the sliding of the particles alongside of each other, so as to loosen their lateral cohesion.