| Name and Model Number | Thacher's Calculating Instrument Type I / K&E |
| Country of Origin | England/USA |
| Date of Manufacture | c.1885-86 |
| Front Scales | A in 40 segments |
| Back Scales | B & C (ˆ ) in 40 segments |
| Scale Length | 9.14 m |
| Type of Rule | Cylinder |
| Construction | Metal cylinder. Metal sliding cage made up of 40 triangular rods. Scales printed on paper and glued on cylinder and rods. Brass end supports and mahogany base. |
| Area of Use | Generic |
| Comment | Early Type I example with serial number 61 stamped in end of right hand knob. The serial number is also stamped into the foot one of the brasss support brackets. The serial number dates this Thacher to c. 1885-86. Paper scale surfaces probably printed in England and applied to device by K&E in the US. K&E brass tag at back right of support base. Condition is excellent. Included is a first edition of the instruction manual dated 1884. Purchased from an heir to the original owner, Joseph Warren Hoover, founder of Kansas City Bridge Co. |
| Rarity | RRR |
| Donor | Collection of Ed Chamberlain |
| Match Number | 188 |
| Thumbnail (Click Picture for Details) |  |
| In conjunction with our 'donors' we assign a rarity rating to each item, based on the system devised by Herman van Herwijnen |
| (1929 - 2004), renowned Dutch collector, author, and creator of Herman's Archive, a collection of 5,000 slide rule images on CD. |
| • RR = Rare - 1 of 25 collectors has one; it may take a year to find an example in the marketplace. |
| • RRR = Very Rare - only a few known to collectors; may be several years before it comes up for sale. |
| • RRRR = Extremely Rare - a museum piece; unlikely that an example will come up for sale. |