 | Edward Charles Frome - Mathematical geography - 1840 - 232 pages
...of an inch in diameter, placed in the focus of a parabolic reflector, and raised to an intense heat by a stream of oxygen gas directed through a flame of alcohol, produced a light eighty times as intense as that given by an argand burner. A station on the hill,... | |
 | Edward Charles Frome - Military topography - 1850 - 292 pages
...of an inch in diameter, placed in the focus of a parabolic reflector, and raised to an intense heat by a stream of oxygen gas directed through a flame of alcohol, produced a light eighty times as intense as that given by an argand burner. A station on the hill in... | |
 | Sir Henry Edward Landor Thuillier - Surveying - 1851 - 826 pages
...of an inch in diameter, placed in the focus of a parabolic reflector, and raised to an intense heat by a stream of oxygen gas directed through a flame of alcohol, produces a light eighty times as intense as that given by an Argand burner, and is visible even in... | |
 | William Mitchell Gillespie - Surveying - 1869 - 550 pages
...truncated cone of burnished tin will reflect the sun's rays to the eye in almost every situation. Eut a " heliotrope," which is a piece- of looking-glass,...produced by a stream of oxygen gas directed through aflame of alcohol upon a ball of lime. Its distinctness is exceedingly increased by a parabolic reflector... | |
 | Early English newspapers - 1896 - 966 pages
...consisted of a ball of lime, placed in the focus of a parabolic reflector, and raised to an intense heat by a stream of oxygen gas directed through a flame of alcohol. The brightness of this light was so intense that on one occasion it rendered the station at Slieve... | |
 | John Whitelaw - Surveying - 1902 - 638 pages
...lime about \ in. diameter placed in the focus of a parabolic reflector and raised to an intense heat by a stream of oxygen gas directed through a flame of alcohol. This produces a light eighty times the intensity of an Argand burner. In boisterous and hazy weather... | |
 | Surveying - 1911 - 336 pages
...placed in the focus of a parabolic reflector, and raised to an intense FIG. 109. FTG 110. FIG. III. heat by a stream of oxygen gas directed through a flame of alcohol, produces a light eighty times as intense as that given by an Argand burner, and is visible even in... | |
 | John Whitelaw - Surveying - 1916 - 582 pages
...lime about \ in. diameter placed in the focus of a parabolic reflector and raised to an intense heat by a stream of oxygen gas directed through a flame of alcohol. This produces a light eighty times the intensity of an Argand burner. In boisterous and hazy weather... | |
 | John Whitelaw - Surveying - 1924 - 642 pages
...lime about \ in. diameter placed in the focus of a parabolic reflector and raised to an intense heat by a stream of oxygen gas directed through a flame of alcohol. This produces a light eighty times the intensity of an Argand burner. In boisterous and hazy weather... | |
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... Captain Kater. By means of this a station 48 miles distant was observed. The most powerful night signal is, however, Drummond's light. This was invented by Lieutenant Drummond, and consists of a ball of lime about \ in. diameter placed in the focus... 