A new exposure meter
β
Watrins, Alfrd
π
Article
π
1890
π
Wiley (John Wiley & Sons)
β 352 KB
\\'hen qir.itf Iinnl, it wiis tlieii either pliicctl iiiider ii belljiir coiitniiiiiig ii dish of wiitcr or csposed to tlic air of tlie roiii. Iri riiost ciircs 11 dupliciitc slide wiis rriiitlc iuitl wiis kept iii tlie dcsiccntor for coiiiparisoii. It woiiltl lie tedious CU rccoiiiif 1111 tlic csp