From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Guide to the Greek alphabet and its common usage in technical notations.
| Identifier | ExFiles\Box 33\1\ Scan276 | |
| Date | 1st March 1926 | |
| Y1775 X.1775. GREEK ALPHABET. α alpha β beta γ gamma δ delta ε epsilon ζ zeta η eta θ theta ι iota κ kappa λ lambda μ mu ν nu ξ xi ο omicron π pi ρ rho σ sigma τ tau υ upsilon φ phi χ chi ψ psi ω omega Groups in common use :- Constant angles α β γ Variable angles θ φ ψ Cartesian co-ordinates (moving axes) ξ η ζ Direction cosines λ μ ν Used separately :- δ for increments. ε for small angles or quantities. π for radian measure of 180° ρ for volume densities. σ for surface densities. ω for angular velocities (or resistances in ohms) Capitals. Σ (sigma) for summation. Ω (omega) for precessional angular velocities or resistances in megohms. EFC. | ||