Assertion: gallic acid | /r/HasProperty | mentioned at a reading of herschels paper
Facets:
value: at the royal society
type: LOCATION
value: on 14 march
type: TEMPORAL
Source sentences:
text: Gallic acid was mentioned at a reading of Herschels paper on photography at the Royal Society on 14 March 1839, and the somewhat problematic lightsensitive combination of gallic acid with silver nitrate published by Herschel early in 1840.