The Dry Battery triode from Myers is of double ended construction to reduce inter-electrode capacitances and was a successful product and followed on from the bright emitter Universal valve. Initial introduction was in Canada in 1922. However Myers had worked with De Forest, RCA etc in the USA making valves and infringing patents along the way. Technically a good valve the company moved back to the USA after the expiration of the De Forest patents but legal action by RCA for back royalties drove the company to bankruptcy.
The attached .PDF file is a reproduction of a 1924 article from Wireless World.
The red end has the anode connection and the f+ connection.
The black end has the control grid connection and the f- connection. Connectors were originally supplied with the valve.
The electrode supports are held in glass beads. The supports pass through the glass envelope in much the same way as the later miniature all glass valves, there is no obvious sign of a pinch.
The thin glass tube envelope is 16 mm in diameter, and including the base pins is 84 mm tall.
References: Datasheet, 1047 & 3002. Type Dry-Battery was first introduced in 1922.