Essays and addresses / by professors and lecturers of the Owens College, Manchester.
- Victoria University of Manchester
- Date:
- 1874
Licence: Public Domain Mark
Credit: Essays and addresses / by professors and lecturers of the Owens College, Manchester. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
125/576 page 105
![subject. With the rude instruments of the Babylonian and the early Greek astronomers it was impossible to measure to within a single degree, and consequently their opinions were the result, more of speculation than of observation. Their instruments were the ttoXos and the yvupcov, both modifications of the common sun-dial. The former consisted of a hollow hemisphere, the sides of which, and sometimes a point in the centre, cast the shadow on the concave interior, which was at first plain, but afterwards marked with circles parallel to the rim and semi-circles crossing these. In the latter, a pointer or style, sometimes vertical, sometimes directed to the pole star, threw its shadow on a flat surface, marked with lines to divide the interval from sunrise to sunset into twelve equal parts. Herodotus, in Book II. chapter 109, says ttoKov /xev yap koL yvtofJLOva /cat ret SuwSe/ca fxepea rrjs rjixeprjs irapa Ba/3i/- Xcovlcov efxaOou ol EXX^i/e?. But the Babylonians con- tented themselves with rough observations, noting positions by quarter diameters of the moon and times to the nearest quarter of an hour. Thales, the wise man of Miletus, who lived from 630 to 540 B.C., is the earliest Greek astronomer of whose doctrines we have clear and well authenticated evidence. He first taught the true nature of eclipses, and is said by Herodotus* to have foretold the year in which an eclipse of the sun would take place. This eclipse has been identified by the present Astronomer * Book I, chapter 74. tt)v 81 fxeraXXayrjv ravrr/v rrjs rjfieprjs ©aXrjs o Mt/\^crtos Totat Iwat Trporjyopcvve ecrea-Oai, ovpov TvpoOijXf.vo<; hnavrbv Toxnov iv t<2 8r) kou eyeVcTo f] /.UTafSoXyj.](https://iiif.wellcomecollection.org/image/b21727910_0125.jp2/full/800%2C/0/default.jpg)
