Accession No

2692

Brief Description

double reflecting circle, by Charles Augustus Schmalcalder, English, 1815 (c)

Origin

England; London; 82 Strand

Maker

Schmalcalder, Charles Augustus

Class

navigation

Earliest Date

1815

Latest Date

1815

Inscription Date

Material

metal (oxidised brass, silver, brass, iron); glass; wood

Dimensions

box length 242mm; breadth 260mm; height 184mm

Special Collection

Provenance

Purchased from Harriet Wynter Ltd, 08/1980. Purchased with assistance from fund administered by Science Museum London.

Inscription

‘Schmalcalder 82 Strand London’
‘A’ (on one handle)

Description Notes

Double reflecting circle, part oxidised brass. Two circles with silver scales, divided 0-180-0-180-0 by 1˚, subdivided to 20’; each with 4 index arms, 4 verniers on silver, one clamp and one double tangent screw. Counterpoised, centrally pivoting reading microscopes on both sides. Two microscopes for reading zero setting retained by the double arms of the handle. Optics contained between circles. Double horizon glass with two hinged shades. Two index mirrors with 4 pivoted shades. Screw-in telescope moved laterally by knurled screw. Two shaped wooden handles on curved brass arms, with two turned wooden handles fitting within the first. Brass-bound fitted wooden box (brass handles) with iron tool; wood and brass adjusting tool for squares on index mirrors; eyepiece shade for telescope; two knurled brass nuts; 2 brass pieces (the width between the circles) with retaining spring, one with pinhole sights.

References

Events