In Philadelphia, American pianomaker Alpheus Babcock patents a one-piece iron plate for a square piano. His invention allows to use thicker, heavier strings at a higher tension, resulting in a richer, stronger, longer-sustained piano tone, and also improving piano’s ability to hold the tune longer (pianos with cast-iron plates wouldn’t need a tune-up in the middle of a concert, as it was common before Babcock’s invention). However, these advantages come with a trade-off: Babcock’s iron plate makes the tone of a piano thinner and “tinny”. Eventually, a knocking noise develops in a piano, as the tuning pins grow loose in the plate. (This challenge will be solved 29 years later by Henry Steinway, Jr., who isn’t even born at the time when Alpheus Babcock patents his invention.)