Not much is known about this firm of assayers. Charles Riehn was foreman in the assay department at the San Francisco Mint in 1862. August Hemme was a German immigrant born in Hannover in 1834. He died in 1904. Riehn, Hemme & Company is listed at the corner of Montgomery and California Streets in 1864-65, 408 Montgomery Street in 1865, and 432 Montgomery Street in 1866. In 1867-8 the company name changed to associate Mark McDonald with the firm. By 1870, McDonald’s name had been dropped and the firm was then located at 404 Montgomery Street. There are only two known Riehn. Hemme & Company ingots. The form of the Internal Revenue tax paid stamp on this bar is the one assumed to be earlier than the commoner round seal. Here a plain tablet with the word TAX and the dollar amount of the tax payable on the bar. This form would have been used before the round stamps were shipped to assayers and seems to date bars so marked as made after September and probably before December. 1864. The apparent uniformity of this format across several different assayers in different locations suggests to the cataloguer that, rather than an ad hoc measure, this might have been according to Office of Internal Revenue requirements. Also interesting is the observation that the gold content given on one of the known bars is 000 while on the other bar known from this firm it is 001. The firm's name on the bar was accomplished by a rather grand logotype that appears to be identical on both known Riehn, Hemme bars. This bar has had one corner clipped while the other one known (bar number 548 with the OIR stamp on the back) shows two opposing corners clipped. Mr. Ford’s informational card for this ingot bears the notation (in handwriting characteristic of his younger days) “Note corner cut off for assay?” suggesting he wasn’t then sure that was why corners were cut from some bars after manufacture.