JOHAN ERNST ESLING, Berlin

细节

JOHAN ERNST ESLING, Berlin
A lacquered-brass graphometer, signed and dated on the main frame Johan Ernft Esling, Fecit, Berolini 1730, the outer scale divided 10°-180°, the inner scale divided 180°-10°,the alidade with twin apertures, engraved with foliage and swags, now with compass box with silvered dial, blued/silvered needle and clamp, and telescope with bubble-level and cross-bubble, on adjustable staff mount -- 13½in.(34cm.)wide, in later fitted mahogany case

See colour plate

拍品专文

The signature on this piece is engraved yet only the 17 in the date is engraved the figure 30 is stamped, suggesting that a batch of these were made and when sold the final year was inserted.

This piece illustrates how scientific instruments were up-graded over the years. What started in 1730 was enhanced in circa 1800 by the addition of the compass and further enhanced in circa 1875 by the addition of the telescope.