1. This slide rule is one of the first made by A.W. Faber - who later became Faber-Castell.

2. The rule is clearly marked A.W. Faber - the name was changed to Faber-Castell in 1906 (see P.Hopp - Slide Rules - their History Models and Makers.)

3. Faber started making slide rules in 1882.

4. I have a copy of C.N. Pickworth's book "Revised Instructions for the use of A.W.Faber's Calculating Rule" (Note: The edition on my web site is later than the one I quote form here). This gives other clues as to the age of the rule. From internal evidence and a date written on the front, the edition I have was published in or before 1897. The author says "The A. W. Faber Calculating Rule has usually been made of well-seasoned boxwood. Recently, however, an improved form has been introduced, in which the boxwood body is provided with celluloid facings upon which the several scales of the instrument are engraved." This suggests that "all wood" rules were superseded by celluloid faced rules before 1897.

5. In the same book Pickworth also says that in some rules the runner consists of "chisel-like projections" but the A.W.Faber rule has a preferred form of runner with glass in a metal frame. This rule has a cursor (i.e. runner) with both glass and chisel-like projections. The rule described by Pickworth also has trigonometry scales on the back of the slide which this rule does not.

6. The material of construction, the hybrid nature of the cursor and the lack of trig scales all seem to suggest that this rule is one of the earliest Faber models.

7. I am grateful to Warren Burdine who sent me the images of this rule.