The following is from the 1929 Leitz catalog:
PETROGRAPHICAL MICROSCOPE "CM"<
Wide Tube for Oculars of Large Diameter)
Object Stage-Of rotary pattern; the periphery of the stage is furnished with scale and double vernier permitting readings within 0.1°; the stage is furthermore equipped with a removable ring plate and may be clamped in position at any desired orientation; two stage clips are furnished.
Micrometer Screw-Of patented design, making use of ball bearings at the sliding surfaces whereby lost motion is eliminated completely and the mechanism acts entirely independently of lubrication; one head of the micrometer screw is equipped with divided drum for depth measurements and since one interval at the drum equals 0.002mm, measurements are possible within this minute ratio.
Coarse Adjustment-By rack and pinion.
Tube Analyzer-Anastigmatic type with "Ahrens" prism.
Amici-Bertrand-Lens-In centering mount with iris diaphragm, attached to slider, after F. E. Wright, adjustable by rack and pinion.
Cap Analyzer Support Serving as socket for the top analyzer to rest on, provided with index line.
Ocular Adapter-To permit the use of ocularsand tube accessories of small diameter.
Objective Clutch Changer-Of new and patented design for objectives; objectives remain individually and permanently centered.
Three Objective Adapters-Are included.
Illuminating Apparatus-Two-iris-diaphragm type, model "a" with "Ahrens" prism and five-lens condenser No. 2000 (listed on page 114).
Cabinet-Mahogany wood, with lock and key. Note:
For different types of illuminating apparatus, we refer to page 114.