Browse Items (2 total)

Metal, glass

Eyepiece with crosshairs, 12-inch tall, 11-inch long, tube 1-inch outer diameter, missing an objective lens.

Used with galvanometer to read the reflection off the mirror.

Model no. 89, no. 18. Box is 8 ¼ x 8 ½ x 12 inches and screwed closed. Unknown date but estimated around 1908. Used with the selenium cell photometer to measure current and with the photoelectric cell photometer. Visible in pictures of transit room. …