Date: 1924, owned by J.c. Sherman
This is a truly rare instrument, the 88H G Bass. According to the model number list it was produced between 1925 and 1929, but the one pictured here was definitely made in 1924. Perhaps experimental, or pre-production. Either way, it was probably on special order only. It doesn't appear in any of the Conn catalogs I have for that period.
This is a bass trombone pitched in G, so it is pitched lower than a standard bass trombone. Hence the throw rod to reach the longest positions. The owner tells me the throw rod was re-built based on the shape of the case and the hole in the outer slide stay. The case apparently is marked as sold in Seattle, and as that is south of British Columbia, it may be it was ordered by an expatriot from England familiar with the G Bass. It has a #5 bore size, which is about 0.562".