Electrical and scientific instruments and apparatus : november 20th, 1899 (1899)
Elmer G. Willyoung & Co · New York : E.G. Willyoung · leaf 104
clliiiii Photoiiieter][Screeii was devisedby Drs. Lummer and Brodhun of the Reichsanstalt, and used in the photo-metric researches of that institution. In this instrument but one eye isused, thus eliminating any error due to the varying sensibility of the twoeyes, and each of the sources of light… … Fig. 90. Fig. 90 shows tlie arrangement in diagram. C and X are, respectivelythe standard and the lamp being measured. S is an opaque white screenof plaster of Paris receiving liglits on its two sides from C and X, fromwhich it is diffused to the two mirrors M and N. P is composed of tworight…
Electric apparatus and appliances · Equipment and supplies
Internet Archive · Medical Heritage Library · Public Domain Mark 1.0. Free to use for anything.
