Physical description

Part of a series of optical munition snapshots 1940-1947. Refer to Cat No 137 for full details. Black and white photo of optical flat in de luxe case with certificate: “GLASS OPTICAL FLAT, made by Natural Philosophy Laboratory, Melbourne University” Number 18. Accuracy of surface flat within .000,001 inch .... Issued by (signd) T.H.L. Feb 19, 1941. Duplicate copy of Cat no 137; in OMP Album Vol 1 #17.

Inscriptions & markings

In ink on lower left hand corner : “17”. Inscribed on back in pencil: “No. 17”