While this binocular microscope was retailed by Charles G. Ewing of San Francisco, it is clearly of English origin. Charles G. Ewing was an optician and photographer located at 111 Montgomery Street, San Francisco. During the 1870s he served as the treasurer of the San Francisco Microscopical Society.
The signatures on this microscope and many of the accessories bear a distinctive belt and buckle motif. A similar motif has been observed on microscopes made by James Swift, London; see The Great Age of the Microscope. The Collection of the Royal Microscopical Society through 150 years by GL'E Turner, Adam Hilger, Bristol and New York, 1979, pgs. 185 and 186. A binocular microscope sold by Husbands & Clark, Bristol was also observed bearing a signature with a similar motif as was a binocular by Murray & Heath (dated 1864) and two others signed Cary and Edmund Wheeler. It is possible that each of these microscopes originated in the same workshop. A good guess is that they were made by James Powell Swift for export and for the trade.