Social environment and moral progress / by Alfred Russel Wallace.
- Alfred Russel Wallace
- Date:
- 1913
Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Credit: Social environment and moral progress / by Alfred Russel Wallace. Source: Wellcome Collection.
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![IV] Permanence of High ínteílect cross hairs in an astronomical telescope. The holes on the benches would serve to carry cross seats on which the observer could be firmly and comfortably seated while observing a transit of sun, star, or planet. Being open to the south, the Great Gallery would give a magnificent view of the southern sky, and enable observers to determine the altitudes and azimuths of many stars, and of the superior planets Mars, Jupiter and Saturn. The star Alpha Centauri, which was at that period of the first magnitude though now much dimi¬ nished in brightness, would, when crossing the meridian, have been situated about the centre of the field of view as seen from this remarkable feature of the pyramid which, Mr. Proctor considers, was the finest transit-instrument ever constructed for naked-eye observations. Tycho Brahé, with his celebrated Quadrant at Uranienburg, did not attain such a degree of accuracy as did these Eastern astronomers nearly 6,000 years ago. One great superiority of the subterranean observatory over any open- air observations that can be made without telescopes is, that by closing up the end, except for the small aperture required to 23](https://iiif.wellcomecollection.org/image/b18022121_0036.JP2/full/800%2C/0/default.jpg)
