643 De Natuur (1889), 321
Reflector originally silvered inside; now blackened copper. Ash tray at
base o f reflector is of iron. Above the handle is a trigger for igniting the
magnesium ribbon. The same kind of lamp is illustrated in De Natuur,
15 November, 1889, 321.
Joseph J. Solomon was at 22 Red Lion Square, Holborn, from
1849 until after 1880. The firm was associated with Alexandre Lebrun,
Paris, as their agent, which explains the French patent (N° 64623,
granted September 1864). For Solomon, see Clifton (1995), 258.
643
644 GLASS SCREEN (1058) 4/4 19th C.
Mahogany tripod stand and frame holding a glass screen (855 x 845)
for use with a projector. The frame has a metal pin and clamping screw
for height adjustment. Overall height 1,880.
Magnetism
645 UNIVERSAL GEOMAGNETIC INSTRUMENT (472) 1K ~
Signed: M. Meyerstein Gottingen
' Combines a theodolite, dip-circle, declinometer, and
magnetometer
Dip-circle: brass, diameter of base 235; overall height 355.
Dip-needle scale (diameter c. 125) may be platinum, as it has not tarnished.
Divided to 15 minutes of arc, and marked 0° - 90° - O'- 90°-
0°. Needle length 149; ends labelled: AI; BI. Bubble level with graduations.
Two microscopes view the points of the needle each with a vernier,
divided O' - 15' by 20":jlaMpled: I; II. White cards in holders
reflect light onto the verniers. Horizontal circle (diameter c. 200) is tar