Copper gold-plated chronometer

[Copper gold-plated timepiece combination instrument]

Copper gold-plated timepiece combination instrument, 18th century, 46.5cm long and 37cm wide, made in London, England. The old collection of the Qing Palace
One end of the instrument is a sundial with a triangular dial needle. The dial needle is equipped with a level tube and a latitude arc, which can be adjusted according to the geographical latitude of the detection site. There is a copper seat under the horizon plate and a gear device inside. Turn the side screw knob to make the horizon plate rise obliquely or be horizontal. On the other side, there is a watch with a plumb line on the left and right sides of the top, and a long-handle spiral knob on the outside, which can adjust the watch rod. The dial has the inscription “London”
The special feature of this combination instrument is that the dip angle of the dial can be changed by adjusting the level. When measuring, align the composite instrument with the north-south direction, adjust the level on the latitude arc according to the latitude of the observer, and then rotate the long screw to adjust the position of the dial plate until the liquid in the box is horizontal. At this time, the dial plate is parallel to the equatorial plane, the dial needle is consistent with the direction of the earth’s rotation axis, and the sun shadow on the dial needle refers to the desired time
If the compass is used to measure the direction, first fix the straight watch in the center of the dial on the zodiac degree of the day, and then adjust the dial to the horizontal shape by adjusting the level. When the shadow cast by the straight watch coincides with the zodiac degree, it is the noon time. The shadow refers to the north-south direction of the observation site


铜镀金日晷圭表合璧仪晷盘