The excavation of the Jacksonville "Blue China" wreck site yielded the remains of a single brass plaque from a hanging spring-loaded scale used for weighing. An inscription runs widthwise along the head of the plaque in capital letters and reads in two lines “WARRANTIED AND MADE BY” with “MORTON &…” (for Morton & Bremner of New York) stamped in a semi-circular curve on the left side before the plaque breaks away (plaque fragment L. 15.0cm, W. 4.1cm, Th. 0.11mm, rivet Diams. 0.45cm).
The spring scale apparatus with which this artifact was once associated is perhaps the simplest form of weighing instrument known. It consisted of a spring fixed at one end with a hook used to suspend the object being weighed at the other; it functioned on the tendency of stretched or compressed metal to return to its original position when the load is removed. This concept is derived from Hooke’s Law of 1660, which states that the distortion of a metal is proportionate to the load applied. The practical application of Hooke’s Law was first put into practice in 1696, when Jacques Ozman produced a ‘balance’ using the change in length of a coiled spring under load to indicate weight.
Later innovations produced a spring balance consisting of a metal tube with a load hook attached to the bottom containing a spring-loaded, graduated bar. As the load was increased, compressing the spring, a greater length of the bar was exposed and the weight could be read from it. Several variations of this design followed, which was a popular and convenient form of weighing used for trade and in households alike. The basic design continued in production until 1960.
Colonel Andrew Augustus Bremner and Major Thomas Morton, both formerly of the Seventh Regiment National Guard, State of New York, were engaged in the manufacture of spring balances and fancy steel goods from 1841 to 1854. According to the New York Mercantile Union Business Directory 1850-51, Morton and Bremner were located at 61 Elizabeth Street in New York City. However, by May 1852 the address for their Spring Balance and Steel Manufactory was 389, 391, 393 First Avenue, where it was subsequently destroyed by fire.
Following Bremner’s retirement in 1854 (Clark, 1980: 226-7; Swinton, 2009: 8), the business continued under Thomas Morton, as clarified in an advertisement in Scientific American of 24 September 1859, which offered “Improved Spring balances capable of sustaining from 8 ounces to 1,000 pounds each, suitable for post-office scales, butchers, icemen, grocers, fruit and flower dealers; also much used by leather inspectors….made to order and offered for sale by the manufacturer, Thos. Morton (late Morton & Bremner), 212 Pearl Street, New York”.
The discovery of the remains of the front plaque from a Morton & Bremner spring scale suggests usage aboard the vessel for weighing grocery cargo upon receipt or delivery. Its New York place of manufacture further supports the ceramic evidence pointing to this city as the ship’s home port. Additionally, the dates in which Morton & Bremner worked together and subsequently parted ways significantly narrows down the wreck’s date to between the years c. 1851 and 1854/5.