# Science and Industry, Volume 7

Colliery engineer Company, 1902 - Industrial arts

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Page 634 - AH a unit of resistance, the international ohm, which is based upon the ohm equal to 109 units of resistance of the CGS system of electromagnetic units, and is represented by the resistance offered to an unvarying electric current by a column of mercury at the temperature of melting ice, 14.4521 grams in mass, of a constant cross-sectional area and of the length of 106.3 centimetres.
Page 457 - Every body continues in its state of rest or of uniform motion in a straight line, except in so far as it is compelled by force to change that state.
Page 514 - Every body continues in its state of rest, or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it.
Page 260 - Bushings must be long enough to bush the entire length of the hole in one continuous piece, or else the hole must first be bushed by a continuous waterproof tube.
Page 242 - In the history of mechanical art two modes of progress may be distinguished — the empirical and the scientific. Not the practical and the theoretic, for that distinction is fallacious : all real progress in mechanical art, whether theoretical or not, must be practical. The true distinction is this : that the empirical mode of progress is purely and simply practical ; the scientific mode of progress ia at once practical and theoretic.
Page 260 - Must be placed on all service wires, either overhead or underground, as near as possible to the point where they enter the building and inside the walls, and arranged to cut off the entire current from the building.
Page 143 - L = length of stroke, in feet; A = area of piston, in square inches; N = number of strokes per minute = number of revolutions x 2. PLAN " " " 33,000 ' The derivation of this formula is explained, as follows: The area of the piston, in square inches, multiplied by the mean effective pressure, in pounds per square inch, gives the total force acting on the piston, in pounds.
Page 260 - No. 51.) a. Must be placed on all service wires, either overhead or underground in a readily accessible place, as near as possible to the point where the wires enter the building, and arranged to cut off the entire current.
Page 260 - In all wiring special attention must be paid to the mechanical execution of the work. Careful and neat running, connecting, soldering, taping of conductors and securing and attaching of fittings, are specially conducive to security and efficiency, and will be strongly insisted on.