Microscope Museum

Collection of antique microscopes and other scientific instruments

Flash point tester by De Grave, Short & Comp.

Flash point tester made by De Grave, Short & Comp, engraved with the number 118, probably dated to 1880. The instrument came with its original wooden box containing a paper label of the company. The instrument is also labelled with a plaque “BOROUGH OF BRIGHTON 1880”, and engraved with several calibration marks dated from 1880, 1904, 1911, 1928, 1941, 1951 and 1961. Flash point testers are designed to test and determine a sample's flash point, i.e., the lowest temperature at which a vapour will flash, when exposed to a naked flame (for example volatile liquids such as petroleum). This instrument should be a version of the Abel’s petroleum test apparatus, as recommended by the Board of Trade Petroleum Act, 1879, as featured in the catalogues of several companies of the early 20^th century (Figure 1). The instrument came with two lids for the oil chamber, a former lid without stirrer, and a second updated lid allowing the fitting of a stirrer for testing the flashing point of petroleum mixtures as required after 1907. De Grave was originally established by Charles De Grave in London in circa 1767, and produced weights, scales, and measures. Charles died in 1799 and left his business to his wife Mary. Charles’s sons, named Charles and Edward Abraham, eventually became involved in the trade variously on their own accounts and in partnership as De Grave and Son(s) between 1817 and 1844. At this time, the business was located at 59 St. Martin's-le-Grand, London. Upon Mary’s death, in 1845, Charles De Grave took on a partner, Samuel Robinson Short, renewing the name to De Grave, Short & Co but this title was short-lived owing to an additional partner William Fanner joining in 1871 to form De Grave, Short & Fanner. At some point the name of the company reverted again to De Grave Short & Co and the firm was later purchased by W & T Avery, in 1919.

Figure 1. Abel’s petroleum test apparatus as featured in a 1914 catalogue of Baird & Tatlock: (A) model with a lid without a stirrer; and (B) an updated standard pattern, with stirrer, for testing the flashing point of petroleum mixtures as required after 1907.