dynactiˈnometer ? Obs.
[f. Gr. δύν(αµις power + ἀκτίς (ἀκτῑν-) ray + µέτρον measure: see -meter, and cf. actinometer.]
An instrument designed to measure the intensity of the photogenic rays, and to compute the power of object-glasses.
| 1851 M. Claudet in Philos. Mag. |