"Sheepshanks" Comparator, 1845-55, for Yard Standards, with scales tank mounted on roller carriage, standing on 3" thick slate base plate, 4' 0" x 5' 6 1/2". The whole apparatus 3' 4" high
"Sheepshanks" Comparator, 1845-55, for Yard Standards, with scales tank mounted on roller carriage, standing on 3" thick slate base plate, 4' 0" x 5' 6 1/2". The whole apparatus 3' 4" high