Arizona republican., 1898-01-22

representing the incandesc scent ele- ments in the original. Photographs of that ring spectrum were obtained in 1893 and 1896, and special efforts will be made today to get better ones than ever before. Sir Norman Lock yer f5 ii charge of most of this work.
 It will be remembered that close 10, or a little above, the photosphere of the sun (the starting point or base line in observations of this sorD, there lies a layer of incandescent gas from five thousand to ten thousand miles thick. It has beautiful pink hue, and is thought to be composed mainly of hydrogen, although evidence of calcium, helium and at least dozen other elements have been found there. In photogra ph of the ring spectrum, taken at the instant of totality, all the irregularities of this layer (the chro- mosphere) due to upheaval into pro- tuberances will be in miniature in those lines which correspond to ele- ments peculiar to the chromosphere. The outer envelope of the sun, that vast, irregular, white mass of haze which is called the corona, has diff ferent composition; and the lines which are produced in the ring spec trum by its ingredients faintly repro duce the outlines of the corona. Hence, by their form, as well as by their position in the scale, they can be distinguished from the chromosphe- ic lines. More and better photogr aphs are needed, however, to make clear these distinctions and to reveal the truth on some other points.
 A question which many students of solar physics hope to see settled by their observations relates to the ex- istence and position of what is some times called the reversing layer" In the ordinary spectrum of the sun the lines are black instead of bright. Lab oratory experiments have shown that if behind mass of the incandescent vapor of substance some other source of light be placed, precisely this effect will be obtained, whereas if only the light of the vapOr itself enters the spectroscope the lines will be bright. It has been thought prob able, therefore, that the dark lines of the solar spectrum are due to the fact that the masses of vapor which produce them have behind or under them the intensely brilliant light-giv- ing photosphere. There is some dis agreement, however, as to the posi- tion of the vapors which reverse the lines. Professor Charles A. Young of Princeton, for many years the most eminent solar spectroscopist of Amer ica, holds that there is a special stra-- um of gas or mixed gases, which he calls the reversing layer" Ard he places it down next the photosphere
 under both the chromosphere and corona.
 He says that during the total eclipse of 1870, while he was examin- ing the sun, there was just an instant when the moon shut off the photo- spheric radiance, but Jeff this SUD- posed layer exposed edgewise Up to that moment in his spectroscope the lines were dark. Then for an ex- ceedingly brief period they all fash
 ed up as bright ones. The onward
 movement of the moon quickly cover ed the layer, and thereafter he could see only the chromospher.c or cor on5i lines. In 1896 MT. Shackleton obtained photograph at the very in- stant corresponding to Professor Young's flash" and it showed bright line spectrum Some foreign spec troscopists, notably Sir Norman Lock yer, are, not yet willing to accept Pro- lessor Young's theory Sir Norman imagines that the reversal. or "ab- sorption," is produced irr regions of the solar atmosphere much highe T than this; either the upper part of the chromosphere or the lower part of the corona, perhaps both. A good many observers will keep watch Sat urday noon for Professor Young's flash" and fresh attempts to photo graph it will be made. On the other hand, Sir Norman Lockyer hopes to obtain a. substantial coGroboration of his views on this point about the strat- ification of gases, and of his belief that many of the substances which we consider elementary are complex and are dissociated by the suns in- tense heat into more simple ones.