The Viennese Uhlmann firm was one of the most important manufacturers of woodwind and brasswind instruments through the 19th century.  Johann Tobias Uhlmann built instruments in Vienna from 1811 until his death in 1838.  Joseph Ulhmann continued his father's work until his death in 1859, at which point his second son Leopold Uhlmann continued the business producing brass instruments.  The stamp as originally used by J.T. Uhlmann was "eagle/I.T. UHLMANN/WIEN/sunburst," which was continued after his death by his son until the mark changed in the 1850s to "JOHANN UHLMANN & SÖHNE/WIEN."  It should be noted that the change in stamp did not match the change in ownership of the firm as numerous instruments were produced during this intermediate period with the original Johann Tobias Uhlmann stamp, and some instruments even continued to use the original stamp into the 1870s.  Uhlmann instruments are relatively rare, and there is only one other surviving bass clarinet by this maker as far as I know (Edinburgh, ex-Shackleton Collection). 

Instrument Specifics:
Key: Bb (Pitch A438)
Materials: Maple, Nickel-Silver
Key Mechanism: Baermann-System with rings, no LH extra keys for F and Eb, descending to E

This instrument is in wonderful condition, and comes with the original case.  The mouthpiece had originally been shortened, but a sleeve has been constructed to extend the mouthpiece body to the original length based on measurements of other mouthpieces from the same time period.  The top joint has most likely been shortened 5 mm based on the molded inserts in the case and a corresponding "cut and solder" repair to the long LH pinkie keys.  The combination of a shortened mouthpiece and shortened distance between the two main joints seems to indicate a desire to raise the pitch to A440.  The longer mouthpiece now lowers the pitch to A438 (the originally pitch might have been as low as A435).  The bell appears to be the original length.  There are no cracks or splits in the maple body, though the bottom tenon has several small chips.  Such in instrument is a rare addition to any instrument collection, let alone an instrument in playing condition.  The intonation at A438 is remarkably stable and and the tone is full-bodied and dark in the lowest register and agile enough in the upper register to blend with high clarinets in the context of the orchestra.  Such an instrument would likely have been used in Vienna as an operatic bass clarinet (in conjunction with bass clarinets in C and A) as well as an orchestral bass clarinet, possibly used for music as late as Mahler and Richard Strauss.