The Detroit Glass Minnow Tube was sold in 1914 and 1915. There were two versions of the lure. The first version is shown in the first photos below. To insert a minnow, the front line tie spring was squeezed to allow the name plate to be moved out of the way. This was not easy to do and was a problem for some fishermen. The second version had a plastic screw off cap on the end to allow the fisherman to install the minnow. This second version made it easier to insert a minnow. An advertisement showing the second version, as well as two new products, can be seen in the June, 1915 ad below.
The DETROIT GLASS MINNOW TUBE First Version
The DETROIT GLASS MINNOW TUBE Second Version (Photo by David Lehmann)
DETROIT GLASS MINNOW TUBE Ad in January, 1914 Hunter-Trader-Trapper Magazine
DETROIT GLASS MINNOW TUBE Ad in April, 1915 Forest and Stream Magazine
DETROIT GLASS MINNOW TUBE Ad in June, 1915 System Magazine