Directions for making an universal meridian dial, capable of being set to any latitude; which shall give the mean solar time of noon, by inspection, without any calculation whatsoever / By Francis Wollaston.

Licence: Public Domain Mark

Credit: Directions for making an universal meridian dial, capable of being set to any latitude; which shall give the mean solar time of noon, by inspection, without any calculation whatsoever / By Francis Wollaston. Source: Wellcome Collection.