Details
C. COLLINS, London
A lacquered-brass binocular petrological microscope, with dividing eyepieces, twin-prisms in carrier, rack-and-pinion and fine focusing, circular stage with silvered-scale divided 0°-360° and signed Watson & Son, Patent No. 41, sub-stage condenser and plano/concave mirror, on raised horseshoe foot signed C. Collins, London, 157 Gt. Portland Street -- 18in.(46cm.)high, with a Webster Condenser, objectives and other accessories in fitted mahogany case
A lacquered-brass binocular petrological microscope, with dividing eyepieces, twin-prisms in carrier, rack-and-pinion and fine focusing, circular stage with silvered-scale divided 0°-360° and signed Watson & Son, Patent No. 41, sub-stage condenser and plano/concave mirror, on raised horseshoe foot signed C. Collins, London, 157 Gt. Portland Street -- 18in.(46cm.)high, with a Webster Condenser, objectives and other accessories in fitted mahogany case
Literature
Turner, G., "The Collins Graduating Diaphragm of 1865", in the Bulletin of the Scientific Instrument Society, No. 40, March 1994, p.25-6.