512. English Balance Scale. Roberval principle. Equal arm. Oblong wood base 8" wide x 4-5/8" deep, on four wood legs. Brass upright; one round plate, one oblong plate. Two recesses in base hold two sets of five nested brass weights; one set in oz., one set in tolas. Markings: "warranted Accurate." Signed: "STS Trademark." (Samuel S. Turner).