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 ebonite base looks to be home-made - probably using the fixings supplied with the valve.
The original box for the Dry-Battery valve.
Thanks to Joe Gruber for sending the images.
The thin glass tube envelope is 16 mm in diameter, and including the base pins is 85 mm tall.
References: Data-sheet, 1047 & 3002. Type Dry-Battery was first introduced in 1922. See also 1922 adverts.