A Popular History of Astronomy During the Nineteenth Century Fourth Edition
CHAPTER I
FOUNDATION OF ASTRONOMICAL PHYSICS
Schwabe's Discovery of a Decennial Sun-spot Period--Coincidence with Period of Magnetic Disturbance--Sun-spots and Weather--Spectrum Analysis--Preliminary Inquiries--Fraunhofer Lines--Kirchhoff's Principle--Anticipations--Elementary Principles of Spectrum Analysis--Unity of Nature 125