Wynne's Innfallible actinometer. Watch form actinometer, plain glass and mask with standard tint over paper disc. Cailbrated in German. Wynne's Infallible actinometer
Wynee's Infallible Hunter meter. Watchform actinometer. Sensitive paper visible through window in the face; two scale 1/128 - 64, F. 4-362. Wynne's Infallible Hunter meter
Wynee's Infallible Hunter meter. An actinometer - pocket watch form; opens to reveal sensitive paper holder in one half and calculator in the other, Scales: 64 seconds to 1/1000, f.3 1/2-156. Wynne's Infallible Hunter meter
Wynne's Infallible Actinometer. Watch-form actinometer, clear glass and mask with standard tint over sensitive paper disc. Yellow filter disc cemented on rotating glass. Wynne's Infallible actinometer