70 KANSAS CITY REVIEW OF SCIENCE. 
the result of most intense heat. Great masses, or clouds of vapor charged with 
these gases exhibit the most fitful and ever-changing forms which it is possible for 
us to conceive. Realize if you can, the effects of one of our most violent hur- 
ricane storms in which the wind travels two or two-and-a-half miles in a minute, 
and smashes the largest buildings and trees it meets. Then picture in the 
mind a raging storm as much more violent than the hurricane as the hurricane 
exceeds a gentle breeze, and you may approach a faint idea of the wonderful 
commotion that sometimes pervades the surface of the sun. 
When a mountain mass many hundred miles in extent, or a vast whirlpool 
of equal area, is actually seen to form and then scatter and disappear in less 
than one hour, we have strong proof of the great activity just alluded to. Moun- 
tain forms of burning hydrogen make up the rose colored prominences which 
nearly always exist along the edges of the sun. Before the invention 
of the spectroscope, these ‘‘red flames” were seen only during total eclipses of 
the sun. But now, this wonderful instrument shows them any tame when they 
are large enough to be seen. 
A solar outburst of much interest was observed by Prof. C. A. Young, of 
Dartmouth College, in 1871, September 7th. On that occasion he saw what 
seemed to be tongues or filaments of burning hydrogen shoot up from a great 
prominence whose height was already 100,000 miles, to an elevation of 200,000 
miles—having made the hundred thousand miles in ten minutes—denoting a 
velocity of 167 miles per second. 
I understand the Professor, as well as R. A. Proctor, of England, to entertain 
the idea that the internal forces of the sun are sufficient to, and possibly do, eject 
solid matter from the sun’s interior never to return; and that ‘‘it is by no means im- 
possible that some of the specimens of meteoric iron in our cabinets are really 
pieces of the sun.” Whether or not this theory is tenable, there is no want of 
evidence that most astonishing forces do exist in the sun. 
The general theory of sun spots, as I understand it, is, that amid the mighty 
rush of torrent vapors great rents or openings are made in the photosphere 
(outer visible surface of the sun) extending deep in the sun’s interior ; and that 
a spot is simply a black and vacant space-—the ‘‘central darkness” of a solar 
whirlpool. In regard to the cause of solar spots, etc., I wish to introduce an- 
other paragraph from C. A. Young: ‘‘ What are the causes of such eruptions it 
is impossible to state as yet with any certainty; still, knowing what we do of 
the enormous amount of energy which the sun is continually pouring out in the 
form of heat, it is nothing strange that such things should occur, and that on a 
solar scale.” 
A feature of much interest in connection with sun spot periods is their cor- 
respondence with similar periods of Aurora Borealis, and magnetic force of the 
earth; the greatest prevalence or maximum of each one accompanying that of 
the other. A noticeable instance of this occurred in 1859, September 1st. Two 
observers in England were examining a large group of sun spots at the same 
