Langley's Instrument for Measuring Radiant Energy

This page is the CodyCross answer for the clue below from African grasslands, Group 1541, Puzzle 3 (African Elephants).

Question is: Langley's Instrument for Measuring Radiant Energy

and the answer is: BOLOMETER

Word Meaning:

BOLOMETER — (physics) A sensitive device for detecting and measuring the energy of electromagnetic radiation.

Definitions from Wiktionary.