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adopted advantage afford allowed American amount application apprentice arts attained attention bearing become better called cents character Cloth consideration desirable diameter directions drawing engineers engravings equal established experience fact follow gauges give given greater hand Illustrated importance improvement inch increased industrial institutes instruction interest iron kinds knowledge labor LECTURE length less machine machinery manufacturing material matter means measure mechanics metal Microscope mind nature necessary object obtained operation particular plane plates points position possible practical preparation present principles produce progress proper reference rule scale schools screw selection sizes skill standard steam strength success surface technical things thread tion trade true truth various wages workmen workshop young
Сторінка 14 - The heights by great men reached and kept Were not attained by sudden flight, But they, while their companions slept. Were toiling upward in the night.
Сторінка 98 - I have indicated. We have therefore in this mode of measurement all the accuracy we can desire ; and we find in practice in the workshop that it is easier to work to the ten-thousandth of an inch from standards of end measure than to the one-hundredth of an inch from the lines on a two-foot rule. In all cases of fitting, end measures of length should be used instead of lines.
Сторінка 51 - Richard likewise observes, he that hath a trade hath an estate, and he that hath a calling hath an office of profit and honor; but then the trade must be worked at, and the calling well followed, or neither the estate nor the office will enable us to pay our taxes. If we are industrious we shall never starve; for...
Сторінка 102 - Thirty years ago, the cost of labour for turning a surface of cast iron, by chipping and filing with the hand, was 12s. per square foot — the same work is now done by the planing machine at a cost for labour of less than one penny per square foot : and this, as you know, is one of the most important operations in mechanics ; it is, therefore, well adapted to illustrate what our progress has been.
Сторінка 92 - A constant proportion is thus established between the depth and the pitch of the thread. In calculating the former, a deduction is to be made for the quantity rounded off, amounting to one-third of the whole depth, that is, one-sixth from the top, and one-sixth from the bottom of the thread. Making this deduction, it will be found that the angle of 55° gives for the actual depth rather more than three-fifths, and less than two-thirds of the pitch. The precaution of rounding off, is adopted to prevent...