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alb5170973

The Time Ball, Royal Observatory, Greenwich, Fig. 1,1844. Creator: Unknown.

The Time Ball, Royal Observatory, Greenwich, Fig. 1, 1844. 'The hour of one o'clock is announced by the descent of a large black ball, from the summit of a pole, which surmounts the northwestern turret of the Observatory; a position singularly favourable for its exhibition to mariners on their progress down the adjacent river Thames. The apparatus...may be said to consist of a hoist for raising the ball, a trigger and discharging gear for its liberation, and a clock, regulated by observation, for giving the required moment of time...Fig. 1, exhibits an upright plan of the first, second, and third floors, on which the apparatus is placed...and a section of the turrets which carries the ball...the supporting shaft bearing the ball on its top and terminating below, at b, in a piston, which works in an air cylinder, d, and by which the too sudden descent of the ball is prevented....'. From "Illustrated London News", 1844, Vol V.
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Title:
The Time Ball, Royal Observatory, Greenwich, Fig. 1,1844. Creator: Unknown.
Caption:
The Time Ball, Royal Observatory, Greenwich, Fig. 1, 1844. 'The hour of one o'clock is announced by the descent of a large black ball, from the summit of a pole, which surmounts the northwestern turret of the Observatory; a position singularly favourable for its exhibition to mariners on their progress down the adjacent river Thames. The apparatus...may be said to consist of a hoist for raising the ball, a trigger and discharging gear for its liberation, and a clock, regulated by observation, for giving the required moment of time...Fig. 1, exhibits an upright plan of the first, second, and third floors, on which the apparatus is placed...and a section of the turrets which carries the ball...the supporting shaft bearing the ball on its top and terminating below, at b, in a piston, which works in an air cylinder, d, and by which the too sudden descent of the ball is prevented....'. From "Illustrated London News", 1844, Vol V.
Technique/material:
engraving
Credit:
Album / The Print Collector/Heritage Images
Releases:
Model: No - Property: No
Rights questions?
Image size:
2050 x 4960 px | 29.1 MB
Print size:
17.4 x 42.0 cm | 6.8 x 16.5 in (300 dpi)
Keywords: