Barnaby

Here is what we believe to be our oldest lamp, who we have named Barnaby, after an old catses. He's carbon filament and has a cap that is 15.7mm in diameter, slightly larger than the standard SBC size of 15mm. He just fitted into our test box socket for testing, but I didn't force him..! He does light, by the way, I wound the Variac up to around 60-70V until the filament began to glow, but I didn't go any further. There are no markings or etches anywhere on this lamp; if anyone has any information as to possible age or origin, please comment below.