GENERAL SUMMARY 



OF 



SCIENTIFIC AND INDUSTRIAL PROGRESS FOR 



THE YEAR 1871. 



The year that has closed lias not been remarkably fruit- 

 ful in the way of great discoveries in science, although much 

 progress has been made in filling out the gaps in our knowl- 

 edge of many subjects. "VVe propose here to take up the 

 several departments in succession, and to indicate as briefly 

 as possible what appears to be most worthy of note, especially 

 so far as the United States is concerned. 



The most interesting among the researches in Astronomy 

 during the year have been those devoted to comets and the 

 corona. The successful observation of four total eclipses in 

 as many consecutive years is something without precedent 

 in the history of Astronomy. The first eclipse, that of 1868, 

 showed that the protuberances were composed mainly of hy- 

 drogen gas. The eclipse observed in this country in 1869 

 showed that the corona was at least in great part gaseous, 

 but did not indicate that the gas was identical with any 

 known terrestrial substance. Owing to the unfavorable 

 weather which extended over the whole line of the eclipse of 

 1870 in the Mediterranean, little more was done on the coro- 

 na than to confirm this discovery, and to show that the now 

 celebrated " green line," by which the gas was indicated, ex- 

 tended to a distance of fifteen or twenty minutes from the 

 sun more than half the diameter of the latter. Perhaps the 

 most important discovery made during this eclipse was one 

 by Professor C. A.Young, who observed in Spain. At the in- 

 stant of commencement of totality he saw all the dark lines 

 of the fading spectrum he had been watching suddenly re- 

 versed, so as to show bright on a dark ground. This appear- 

 ance lasted only one or two seconds. The conclusion drawn 

 from this appearance is that the entire surface of the sun is 

 covered with a thin layer or glowing atmosphere composed 

 of the vapors of all the substances known to exist in the sun. 



