Three (3) Daemen, Schmidt & Co., Zurich, Switzerland, Loga Rechenwalzen Cylindrical Slide Rule Calculating Drums, including one (1) 15m, one (1) 10m, and one (1) 2,4m. Each comprised of varnished paper scales on a metal cylinders with sliding, slotted cylindrical cages secured by aluminium rings with knobs, 15m and 10m models with small clear celluloid indicators attached to the slats, all mounted on aluminium support stands. Maker's marks to rings or drums, 15m and 10m models with maker's marks or sticker to drums, stands with embossed lettering reading "LOGA" to both sides. Drums range in size from 12 5/8" W x 2/12" dia. to 23 7/8" W x 6 1/4" dia. Overall dimensions range in size from 4" H x 13 1/4" w X 3 1/4" W to 9 1/2" H x 25 1/4" W x 8 1/8" D. All items second quarter 20th century. Provenance: Private West Tennessee Collection. CONDITION: All items in overall good condition with surface wear to varnish paper and metal to be expected from age and manner of use. 2,4m model with missing knob, remaining knobs with areas of rust.