Untitledfrom any substance which has been made incandescent may be observed withthe spectroscope in the same way, and each element can be thusseparated. It is found that each substance (in the same conditions ofpressure, etc.) gives a constant spectrum of its own. _Each metaldisplays its own distinctive colour. It is obvious, therefore, that thespectrum provides the means for identifying a particular substance._ Itwas by this method that we discovered in the sun the presence of suchwell-known elements as sodium, iron, copper, zinc, and magnesium.[Illustration: _Yerkes Observatory._FIG. 9.--THE GREAT SUN-SPOT OF JULY 17, 1905][Illustration: _From photographs taken at the Yerkes Observatory._FIG. 10.--SOLAR PROMINENCESThese are about 60,000 miles in height. The two photographs show thevast changes occurring in ten minutes. October 10, 1910.][Illustration: _Photo: Mount Wilson Observatory._FIG. 11.--MARS, October 5, 1909Showing the dark markings and the Polar Cap.][Illustration: FIG. 12.--JUPITERShowing the belts which are probably cloud formations.]
This is the end of the preview.
access the rest of the document.
dark lines, Yerkes Observatory, Bright Lines