This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1892 edition. Excerpt: ...from the pendulums, and so set that in their oscillation their ends move with exceedingly little friction on the surface of a circular glass plate, which at the time of the earthquake is made to rotate, and they thus trace a pair of magnified records of the earth's horizontal motion in two components, ...
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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1892 edition. Excerpt: ...from the pendulums, and so set that in their oscillation their ends move with exceedingly little friction on the surface of a circular glass plate, which at the time of the earthquake is made to rotate, and they thus trace a pair of magnified records of the earth's horizontal motion in two components, side by side, on the surface of the smoked glass plate, which may then be varnished and used as a negative for taking photographic copies. The vertical component is recorded on the same revolving glass by a pendulum standing on the opposite side. In this there is a massive bar pivotted on a horizontal line, about which it oscillates freely in a vertical direction. The bar is held up by a pair of long spiral springs, and by adjusting the point at which the pull of the springs is applied to the bar, so that it may be below a horizontal plane through the fulcrum, the equilibrium of the bar is made as nearly neutral as is desirable. The bar is pivotted and the pull of the springs applied by hard steel points working in hard steel centres. A light steel bar is fixed vertically to the edge of the pendulum so as to multiply the motion, and carries at its base a horizontal index, so jointed that a vertical motion of the rod is converted into a horizontal motion of the index in a direction radial to the circumference of the smoked plate. Another piece of apparatus is for setting the glass plate in motion so soon as an earthquake commences. It consists of clockwork which, when in action, drives a small friction roller over the surface of the glass plate near its edge, thereby giving it a uniform speed of rotation. The speed of the clockwork is controlled by a balanced centrifugal governor, furnished with vanes which dip into a vessel containing castor...
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
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Seller's Description:
PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
