This patent, lately granted to John Mc-Murtry, of Lexington, Kentucky, on a sash balance, is worthy of notice. With his arrangement of cog gearing, the sashes can be operated and balanced together, or either the upper or lower one raised or lowered and balanced by itself at any position desired, and locked so as not to fall. Both sashes can be locked down at night by the same knob and catch by which they are operated and held open. This improvement dispenses entirely with cords, weights and box framing, and is better, as each sash can be operated separately.
This article was originally published with the title "Sash Balance" in Scientific American 13, 13, 99 (December 1857)