Thomas Thalric Harman, Showell's Dictionary of Birmingham… (1885)
“ BIRMINGHAM. TRADE MARK. DOLBY'S PATENT BEEF TEA & GRAVY EXTRACTOR The arrangement of this most useful apparatus is such that the heat maintained is exactly the right degree lo insure the "extraction of every particle of nourishment from meat of all kinds, and the result is a true, rich, and highly nourishing gravy, which will entirely supersede the unpleasant and unsavoury preserved extracts of meat now often resorted to for want of a simple apparatus to make rich fresh beef tea and gravies at home. The inner vessel is of porcelain. ”
