Memoirs of the life of David Rittenhouse, LLD. F.R.S., late president of the American Philosophical Society, &c. : $b interspersed with various notices of many distinguished men : with an appendix, containing sundry philosophical and other papers, most of which have not hitherto been publishedBarton, William
History
Memoirs of the life of David Rittenhouse, LLD. F.R.S., late president of the American Philosophical Society, &c. : $b interspersed with various notices of many distinguished men : with an appendix, containing sundry philosophical and other papers, most of which have not hitherto been published
Mr. Lalande (in his _Astronomie_) has been careful to mention, that
the celebrated astronomer Hevelius possessed a similar merit. He
constructed, himself, the very large telescopes and other instruments,
described (with plates) in his great work entitled, _Machina
Cœlestis_, and with which he furnished the Observatory that he
established at his own residence, in the year 1641. Hevelius (whose
true name was John Hoelké.) was the son of a brewer; but was well
educated. He was born at Dantzic the 28th of January, 1611: and after
having made the tour of England, France and Germany, from 1630 to
1634, he was, on his return to his native city, occupied for some time
in the affairs of that little republic; of which he officiated as
consul, in 1651. He died on the anniversary of his birth-day, at the
age of seventy-six years.
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1. An _Equal Altitude Instrument_—its telescope three and an half feet
focal length, with two horizontal hairs, and a vertical one in its
focus; firmly supported on a stone pedestal, and easily adjusted to a
plummet-wire four feet in length, by two screws, one moving in a North
and South, the other in an East and West direction.
2. A _Transit Telescope_, fixed in the meridian, on fine steel points;
so that the hair in its focus could move in no other direction than
along the meridian; in which were two marks, South and North, about 330
yards distance each; to which it could be readily adjusted in an
horizontal position by one screw, as it could in a vertical position, by
another.
3. An excellent _Time-piece_—having for its pendulum-rod a flat steel
bar, with a bob weighing about twelve pounds, and vibrating in a small
arch. This went eight days, did not stop when wound up, beat dead
seconds, and was kept in motion by a weight of five pounds.[117]
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Footnote 117:
For some of the reasons which induced the writer to describe the
instruments used on that occasion, see Note 125.
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Public-domain text, read in full here on John Shaqi.
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