74 THE POPULAR SCIENCE MONTHLY. 



two more, while at Hanover he could only perceive the three brightest 

 of them. The power of the telescope was correspondingly increased, 

 so that an instrument of 9 T 4 g- inches of aperture was as effective as one 

 with 12 inches at the sea-level. Some views of Saturn were exquis- 

 itely beautiful. The inner satellites, the details and markings of the 

 rings, especially a dark stripe upon the outer ring, were clearly seen 

 under powers ranging from 500 to 1,200. Besides the increase of 

 the range of the instrument, the air was vastly more steady, and faint 

 objects much more clearly defined. 



The advantage was still greater in the careful spectroscopic obser- 

 vations that were made. Prof. Young had drawn up at Hanover a cat- 

 alogue of 103 bright lines in the spectrum of the chromosphere; at 

 Sherman the number was extended to 273, while, at moments of un- 

 usual solar disturbance, there were glimpses of at least as many more. 

 Sulphur, strontium, and cerium, are almost certainly proved to be con- 

 stituents of the solar atmosphere, and zinc, erbium, and didymium are 

 strongly indicated. It was hoped that at the base of the chromo- 

 sphere there might be seen the reversal of the dark lines of the spec- 

 trum, which is so wondrously beautiful at the commencement and close 

 of a total solar eclipse. But in this hope the observers were disap- 

 pointed ; the appearance, at the distance of 1" or 15* from the edge 

 of the photosphere, giving a spectrum principally continuous, most of 

 the. dark lines vanishing or being much weakened. This result con- 

 firms the observations of Secchi, who reports at the edge of the sun a 

 layer giving a continuous spectrum. 



Curious observations were made upon the spectra of sun-spots, and 

 a catalogue was made of 155 lines more or less affected, either greatly 

 widened or weakened, or reversed. A number of bright lines were 

 found in the spectrum of the nucleus, and some peculiarly shaded, as 

 if they were the product of a combination of elements which, from the 

 reduced temperature over the spots, had been "able to exercise their 

 chemical affinities. 



Many solar eruptions were watched moving with velocities vary- 

 ing from 150 to 250 miles per second, and pouring forth their whirl- 

 winds and torrents of ejected gas through the molten atmosphere. 

 The most interesting eruption was visible on the surface of the sun 

 itself in the vicinity of a large spot. 



The magnetic observations were as satisfactory as any that were 

 made, and yet prove that, although our greatest magnetic storms are 

 only remotely connected with solar influence, every solar paroxysm 

 has a direct and immediate effect upon terrestrial magnetism. On 

 the 3d and 5th of August there were violent paroxysms of solar erup- 

 tion. At just the minute these eruptions took place, the record of the 

 vertical Magnetic Force shows marked and sudden magnetic impulses, 

 a peculiar shuddering of the magnetic needle for that very time. The 

 photographic copies of the vertical Force Curve at Greenwich and 



