Young, Charles A. (Charles Augustus), 1834-1908, Young, Anne Sewell, b. 1871., ed · Boston, New York [etc.] Ginn and Company · leaf 445
fter reflection first atM (the index-mirror) and then at H (the horizon-glass) ismade to coincide with the ray OH, coming from the horizon..- From the law of reflection, we have the two angles SMPand PMH equal to each other, each being x. In the same way,the two angles marked y are equal. From the… … 426 APPENDIX. [§556 THE PYRHELIOMETER. 556. The pyrheliometer is an instrument devised by Pouilletfor measuring the amount of heat received from the sun, and hemade with it, in 1838, some of the earliest determinations ofthe solar constant. In Fig. 158 aa is a little snuff-box-likecapsule, made of…
Astronomy · Constellations
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