The VT.1 is the Type designation given to the Western Electric Type J by the American Signal Corps. It is also named as part of the WE 203 series as 203A. The American Navy called the valve CW-933.
The valve itself is a rugged triode designed for use as a detector, amplifier or local oscillator. During WWI (1914-1918) Western Electric produced around half a million valves of the VT1 and VT2 type.
In the main image shows deep scoring above the VT1. Within the scratches can be made out the words Signal Corps. This suggests a surplus tube from after the end of WWI when such valves were made available to radio amateurs.
The construction is of a central inverted V filament of twisted tape with grid and anode either side.
The ladder grid is folded into two sections of 15 rungs. The grid has been stamped out of a sheet. The anode is corrugated for strength.
The seam of the base cap and within the filament tension spring.
The ladder grid and anode with central pressing to add extra rigidity to the thin sheet.
The twists in the filament are easier to see in this image. The locating pip for the bayonet base is clearly seen.
Using the μTracer this plot was produced. Note the very low current from this ancient valve.
The wide glass tube envelope is 34 mm in diameter, and excluding the base pins is 96 mm tall.
References: 1047 & internet. Type VT1 was first introduced in 1917.