34 •. "--::>--. . KANSAS CITY REVIEW OF SCIENCE. 



inverse ratio of the square of the distance. The eajth is 92,000,000 miles from 

 the sun, but to arrive at results, a ratio must first be deduced. Suppose that above- 

 where the comet strikes we place a flat surface at. a distance of 100,000 miles, and 

 admit that the radiation of heat hereon from the disintegrated comet' would , be" 

 80,000,000 degrees. Of course it would not be that intense, for of such intensity 

 is the heat 100,000 miles below; but allow that it would be, then how intense will 

 be the heat reaching the earth ? The quotient of 92,000,000 divided by 100,000 

 is 920, and the square of this number is 846,400. Then, the heat falling on the 

 earth is 846,400 times less than that radiating on a surface 100,000 miles from the 

 scene of collision. Dividing 80,000,000 degrees by 846,400 we find the inten- 

 sity of a heat-wave that can reach the earth from the disruption of any comet 

 large or small on the sun to be 94 degrees. Take a hot day with the thermometer 

 at 94 degrees, double the heat for the 1-2,008,908 part of a second, or indeed for 

 half a minute, and observe the eflect on the human species. Really the only way 

 to detect the arrival of the wave would be to turn a large telescope on the sun just 

 before the comet fell, and place in the focus one of Prof. Langley's balometers 

 capable of measuring the 1-50,000 degree of heat, and look intently on the index 

 with a microscope. Even then it is doubtful if movement of the delicate balance 

 could be seen. We should be pleased to have our telescope set upon the precise 

 point of impact at the time the comet falls, to see what would take place. It is 

 scarcely possible that a movement so rapid would make impression on the retina. 

 And high magnifying powers would have to be used, since one second of arc on 

 the solar disc is, in linear dimensions 450 miles, and is as small an object as can 

 be seen in a telescope on the sun. But the comet of 181 1 had for what was sup- 

 posed to be a solid nucleus a diameter of 428 miles — less than one second of angu- 

 lar measurement when at the sun's distance ; hence the final plunge of a comet into 

 the solar flames could only be seen in good telescopes under favorable circum- 

 stances. But a tele-spectroscope of powerful dispersive powers set on the spot 

 after impact might in the spectrum produced exhibit slight disturbance, such as 

 displacement of the Unes caused by outbursts of hydrogen and other gases. 

 Hence : 



7. The effect of cometary precipitation on the sun can not be detected on 

 earth save by the most powerful instruments. What is the sun ? It is a colossal 

 ball 860,000 miles in diameter, whose mighty mass is 331,654 times greater than 

 that of the ea|^;^^:,What is a comet falling into this awful furnace ? Nothing but 

 as one firebrand in the conflagration of Chicago. Explosions are always taking 

 place on the sun, causing greater upheaval than the downrush of a dozen comets. 

 Can cometary collision on the sun injure man? Indeed, such impact serves to 

 keep him alive. The sun does not radiate too much heat now, and astronomers 

 are agreed that part of the present supply is kept up by cosmical bombardment. 

 We are flung away in some nook of the universe chained to an expiring world — 

 a home that is already suffering encroachment of polar ice. We exist only by the 

 heat of the sun. The real danger Hes not in cometary downrush, but in the fear 

 that not enough meteors and comets will gravitate into solar fires. The longer 



