Journal - Franklin Institute of the State of Pennsylvania (1826)
Franklin Institute, Philadelphia, Franklin Institute (Philadelphia, Pa.) · [Philadelphia : Franklin Institute] · leaf 101
Fig. 3.—Astronomical clock. 90 Johnson [J. F. I.. left, marked B, is called an auxiliary clock. It is mountedin exactly the same way as the astronomical clock, but is ofmuch cheaper mechanism and is used only in emergencieswhen it would be necessary to oil or otherwise adjust theastronomical clock.… … FlG. 4.—Theri:.L,;;.„i, air switches, electric switch, telegraphic sounder, etc. vey the compressed air to and from the clock mechanism.The function of the astronomical clock is to control com-pressed air, which moves the hands of the dials 200 feetabove. On the rear wall of the clock room there is…
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