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Improved Patent Portable Theodolite

Improved Patent Portable Theodolite

1818-1826
Double-frame brass sextant.

Double-frame brass sextant.

1810-1826
Prismatic magnetic compass, British, 1810-1826

Prismatic magnetic compass, British, 1810-1826

1810-1826
Prismatic magnetic compass, British, 1810-1826

Prismatic magnetic compass, British, 1810-1826

1810-1826
Case of silver mathematical drawing instruments by C. A. Schmalcalder

Case of silver mathematical drawing instruments by C. A. Schmalcalder

1810-1826
Box type pocket sextant.

Box type pocket sextant.

1810-1826
Gould type microscope by C. A. Schmalcalder

Gould type microscope by C. A. Schmalcalder

1830-1840
Microscope with Jones-type stand

Microscope with Jones-type stand

1800-1825
Patent prismatic clinometer, British, 1810 -1826

Patent prismatic clinometer, British, 1810 -1826

1810-1826
Two prismatic magnetic compass, one with leather case, by Charles Auguste Schmalcalder, Strand, London, England, 1810-1826

Two prismatic magnetic compass, British, 1810-1826

1810-1826
Clinometer patent by C. A. Schmalcalder, 82 Strand, London, England, 1810-1826.

Patent clinometer, British, 1810-1826

1810-1826
Pocket sextant made by Charles Augustus Schmalcalder, London, about 1830. Lacquered brass frame and limb, the detached screw-in handle is missing. Signed on the index arm: Schmalcalder | London. Polished brass scale from -2° to 134° every 30', measuring to 120° (digits are read from the pivot). Brass vernier to 1', zero at the left. There is no tangent or clamping screw; the index arm is moved by hand, by a milled knob. No shades. Index- and horizon-glass adjustment by screws and a fixed milled screw. Sight vane with one pinhole. A mahogany keystone box.

Pocket brass sextant.

1825-1835