 | 1896 - 700 pages
...with great success during the progress of the Irish survey ; it simply consisted of a ball of lime, placed in the focus of a parabolic reflector, and...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 - 1902 - 568 pages
...Drummond's light. This was invented by Lieutenant Drummond, and consists of a ball of lime about \ in. diameter placed in the focus of a parabolic reflector...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... | |
 | 1911 - 336 pages
...heliotropes, Argand reverberatory lamps, and Drummond lights. The latter surpass all previous contrivances. A ball of lime, about a quarter of an inch in diameter,...of a parabolic reflector, and raised to an intense FIG. 109. FIG на FIG. III. heat by a stream of oxygen gas directed through a flame of alcohol, produces... | |
 | John Whitelaw - 1916 - 578 pages
...Drummond's light. This was invented by Lieutenant Drummond, and consists of a ball of lime about \ in. diameter placed in the focus of a parabolic reflector...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 - 1924 - 638 pages
...Drummond's light. This was invented by Lieutenant Drummond, and consists of a ball of lime about \ in. diameter placed in the focus of a parabolic reflector...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 - 1924 - 650 pages
...Drummond's light. This was invented by Lieutenant Drummond, and consists of a ball of lime about \ in. diameter placed in the focus of a parabolic reflector...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... | |
 | 1896 - 726 pages
...survey ; it simply consisted of a ball of lime, placed in the focus of a parabolic reflector, tind 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... | |
| |
heliotrope," which is a piece of looking-glass, so adjusted as to reflect the sun directly to any desired point, is the most perfect arrangement. For night signals, an Argand lamp is used ; or, best of all, Drummond's light, produced by a stream of oxygen... 
