748 KANSAS CITY REVIEW OF SCIENCE. 
The sun is subject to terrific hurricanes and cyclones, as well as explosions, 
casting up jets to the height of 200,000 miles. In the early days of spectroscopy 
these protuberances could only be seen at a time of a total solar eclipse, and as- 
fronomers made long journeys to distant parts of the earth to bein line of totality. 
Now allis changed. Images of the sun are thrown into the observatory by an 
ingenious instrument run by clock work, and called a Heliostat. This is set on 
the sun at such an angle as to throw the solar image into the objective of the 
telescope placed horizontally in a darkened observatory, and the pendulum bal- 
set in motion, when it will follow the sun without moving its image, all day if 
desired. At the eye end of the telescope is attached the spectroscope and the 
micrometer, and the whole set of instruments so adjusted that just the edge of the 
sun is seen, making a half spectrum. The other half of the spectroscope pro- 
jects above the solar limb, and is dark, so if an explosion throws up liquid jets, 
or flames of hydrogen, the astronomer at once sees them and with the micrometer 
measures their height before they have time tofall. And the spectrum at once tells 
what the jets are composed of, whether hydrogen, gaseous iron, calcium or any- 
thing else) Prot... Ay Young saw a jet of hydrogenascend a distance of 200,- 
coo miles, measured its height, noted its spectrum and timed its ascent by a 
chronometer all at once, and was astonished to find the velocity 160 miles per 
second ; eight times faster than the earth flies on its orbit. By these improve- 
ments solar hurricanes, whirlpools and explosions can be seen from any physical 
observatory on clear days, 
The slit of the spectroscope can be moved anywhere on the disc of the sun; 
so that if the observer sees a tornado begin, he moves the slit along with it, meas 
ures the length of its track and velocity. With the telescope, micrometer, 
heliostat and spectroscope came desire for more complex instruments, resulting 
in the invention of the Photoheliograph, invoking the aid of photography to make 
permanent the results of these exciting researches. This mechanism consists of 
an excessively sensitive plate, adjusted in the solar focus of the telespectroscope. 
In front of the plate in the camera is a screen attached to a spring, and held closed 
by acord. The eye is applied to the spectroscopic end of the complex arrange- 
ment to watch the development of solar hurricanes. 
Finally an appalling out-burst occurs; the flames leap higher and higher, 
torn into a thousand shreds, presenting a scene that language is powerless to de- 
scribe. When the display is at the height of its magnificence, the astronomer cuts 
the cord; the slide makes an exposure of 1-3000 part of asecond, and an accurate 
photograph is taken. The storm all in rapid motion is petrified on the plate; 
everything is distinct, all the surging billows of fire, boilings and turbulence are 
rendered motionless with the velocity of lightning. 
At Meudon, in France, M. Janssen takes these instantaneous photographs of 
the sun, thirty inches in diameter, and afterward enlarges them to ten feet; 
showing scenes of fiery desolation that appalls the human imagination. (See ad- 
dress of Vice-President Langley, A. A. A.S., Proceedings Saratoga Meeting, p 56.) 
