l, having an Fig. 4. Heliometer for ascertaining the latitude when the apparatus is set at noon according to the date. It also is used for finding the date and length of day, sunrise and sunset (other conditions being established), the difference of time between two places, the position of the… … Heliotrope. the vertical arc, f. The for the cup, and prevent its being driven into the body by to a distant station. That used in the British triangulation gradations on this arc are the pressure of the atmosphere. In D, the glass has anelas- has a silvered disk, and has been seen at 100 miles…
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