- heliograph (n.)
[heliograph 词源字典]
- product of a certain type of engraving process, 1853, from helio- + -graph "something written." Earlier, "a description of the sun" (1706, implied in heliographic). Heliography (1845 in the engraving sense) also (1840) was an early term for what came to be called photography.[heliograph etymology, heliograph origin, 英语词源]