OK, DuPont Bulk Shotgun Powder was introduced in 1893 and was still in production in 1948. It isn't a true bulk for bulk powder, but it's close to it. It's very hygroscopic, as the bulk powders tended to be. The appearance is sorta egg shaped, but the granules are irregular in size. The bulk powders were noted for being friable, which produces a lot of dust. The dust should be removed prior to use, since the burning rate is affected by the dust.
Bulk powder is a form, not just because it can be loaded bulk for bulk, with some being shotgun powders and others being SR #1 through SR #80. There aren't any bulk powders still in production, with all being dense powders now.
Most of this information was distilled from page 159 of the Sharpe manual.