 | Francis Galton - Travel - 1867 - 376 pages
...of sextants, as those employed on surveying duties very frequently have to perform the operation. " The requisites are clean tinfoil and mercury (a hare's...leaf so that its surface is fluid. Prepare a slip of paper the size of the tinfoil. Take the glass in the left hand, previously well cleaned, and the paper... | |
 | Francis Galton - Travel - 1872 - 462 pages
...of sextants, as those employed on surveying duties very frequently have to perform the operation. " The requisites are clean tinfoil and mercury (a hare's...leaf so that its surface is fluid. Prepare a slip of paper the size of the tinfoil. Take the glass in the left hand, previously well cleaned, and the paper... | |
 | Royal Geographical Society (Great Britain) - Electronic journals - 1872 - 482 pages
...Siltering Sextant Glasses — (Extract from 'Nautical Surveying,' by Admiral Sir E. BELCHER, pp. 9, 10.) The requisites are clean tinfoil and mercury (a hare's...leaf so that its surface is fluid. Prepare a slip of paper the size of the tinfoil. Take the glass in the left hand, previously well cleaned, and the paper... | |
 | sir Frederick George D. Bedford - 1875 - 542 pages
...glasses when injured by damp or wet : — " The requisites are clean tinfoil and mercury, a hares' foot is handy, lay the tinfoil, which should exceed...of a small shot, which rub gently over the tinfoil unt1l it spreads itself and shows a silvered surface, gently add sufficient mercury to cover the leaf,... | |
 | sir Frederick George D. Bedford - 1885 - 628 pages
...»urface (the back of a book), rub it out smooth wilb the finger, add a bubble of mercury about the si'/,e of a small shot, which rub gently over the tinfoil...spreads Itself and shows a silvered surface; gently add «ufflclent mercury to cover the leaf, so that its surface 1ч fluid. Prepare a »lip of clean paper... | |
 | U.S. Coast and Geodetic Survey - Geodesy - 1908 - 140 pages
...quarter of an inch on each side, on a smooth pad of paper; rub it smooth with the finger; add a drop of mercury about the size of a small shot, which rub gently over the tin foil until it spreads itself and shows a silvered surface ; gently add sufficient mercury to cover... | |
 | U.S. Coast and Geodetic Survey - 1915 - 200 pages
...quarter of an inch on each side, on a smooth pad of paper; rub it smooth with the finger; add a drop of mercury about the size of a small shot, which rub gently over the tin foil until it spreads itself and shows a silvered surface; gently add sufficient mercury to cover... | |
 | U.S. Coast and Geodetic Survey - Geodesy - 1921 - 232 pages
...quarter of an inch on each side, on a smooth pad of paper; rub It smooth with the finger; add a drop of mercury about the size of a small shot, which rub gently over the tin foil until it spreads itself and shows a silvered surface; gently add sufficient mercury to cover... | |
 | 1928 - 340 pages
...quarter of an inch on each side, on a smooth pad of paper; rub it smooth with the finger; add a drop of mercury about the size of a small shot, which rub gently over the tin foil until it spreads itself and shows a silvered surface ; gently add sufficient mercury to cover... | |
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The requisites are clean tinfoil and mercury (a hare's foot is handy) — lay the tinfoil, which should exceed the surface of the glass by a quarter of an inch on each side, on a smooth surface (the back of a book), rub it out smooth with the finger,... 