'INCUBATOR FOR THE MICROSCOPE STAGE'

MAKER: CHARLES HEARSON

c. 1920'S-1930's(after 1916)

SIGNED ON THE INSTRUCTIONS:
'CHARLES HEARSON & CO., Ltd.,
  68, Willow Walk, BERMONDSEY,
                                  LONDON, S.E.1.'

SIGNED ON THE BULB: With an 'E' and the numbers '220' and '82' inside a triangle