744 



THE POPULAR SCIENCE MONTHLY. 



EDITOR'S TABLE. 



THE COMING ECLIPSE. 



THEEE is little rest for the astrono- 

 mers. Although their science is 

 the oldest and exactest, and has long 

 since taken its place as one of the most 

 perfected divisions of knowledge, yet 

 there never was a time of greater soli- 

 citude in regard to undetermined celes- 

 tial questions than the present. New 

 problems are presented of transcendent 

 interest, and the progress in the con- 

 struction of instruments and increasing 

 experience in observation are certain 

 to be rewarded with important exten- 

 sions of astronomical knowledge. 



And there is little rest for the astron- 

 omers, not only because of the urgent 

 questions that have recently arisen in 

 their science, but because many of the 

 great phenomena in which they are 

 interested are observable only at criti- 

 cal moments and at rare intervals, and 

 only at a few points upon our planet. 

 The present year will ever be memo- 

 rable in astronomic annals because of 

 the extensive preparations made to 

 study the transit of Venus; but, while 

 the various parties of observers are re- 

 turning from the distant stations upon 

 the globe where their observations were 

 made, other expeditions have been fitted 

 out which are traveling again to distant 

 places to observe an eclipse of the sun. 

 This is to take place on the 5th of April ; 

 is visible only in the Eastern Hem-' 

 isphere, and will be mainly observed 

 from stations in the kingdom of Siam. 

 The shadow of total darkness will sweep 

 rapidly along a line of about one hundred 

 miles in breadth, and the time of total 

 obscuration, when all the grand phe- 

 nomena are displayed, will be but a few 

 seconds more than four minutes. Yet 

 within these fleeting moments many im- 

 posing effects are to be accurately noted 

 which will serve as data for resolving 



the most important questions relating 

 to the constitution of the sun. It was 

 a splendid victory of scientific enter- 

 prise when Lockyer and Janssen showed 

 that eclipses could be dispensed with 

 in studying the solar prominences with 

 the spectroscope, and that with their 

 instruments they can at any time sweep 

 round the solar outline, and watch and 

 define those mighty eruptions of gase- 

 ous matter which rise to a height of 

 tens and even hundreds of thousands 

 of miles above the photosphere, or light- 

 giving portion of the solar atmosphere ; 

 but these observations only heighten 

 the interest of the grand effects which 

 appear when the sun's disk is complete- 

 ly darkened. It is then impressively 

 recognized that this great luminary is 

 very far from being the clear-cut, sharp- 

 ly-defined, luminous globe that it seems 

 to ordinary observation. Its ragged 

 edge is stupendously mountainous, and 

 there moreover stretches away a mighty 

 upper atmosphere, or luminous append- 

 age, called the corona, which can only 

 be examined during the few precious 

 moments of solar darkening. 



The corona is therefore now the 

 grand point of attack in a solar eclipse, 

 by telescopic observation, photographic 

 representation, and spectrum analysis; 

 and, with each step of improvement in 

 the construction of instruments, and 

 the facility of their use, we are justified 

 in expecting important accessions to 

 our knowledge of that remarkable phe- 

 nomenon. 



The preparations for observing the 

 April eclipse are suggestive of other 

 considerations which should not be lost 

 sight of. The interests of science are 

 beginning to be recognized throughout 

 the world, and to bring the most di- 

 verse nationalities into close relation 

 upon a common platform of sympa- 



