H. A. Newton— The Story of Bields Comet. 87 



spoken of), neither of the two Biela comets has been seen. 

 In 1859 their path was to us behind the sun. In 1866 they 

 should have been at the point P on the 26th of January. A 

 better chance of seeing them could hardly be. They were at 

 all times to be away from the sun's light, and when nearest to 

 the earth not more than one-fifth the sun's distance. The paths 

 were carefully computed, and the action of all the planets, nota- 

 bly that of Jupiter, allowed for. A dozen observers for months 

 swept the heavens with their telescopes, but not the slightest 

 trace of the comets was seen. 



Again, they should have come to perihelion a year ago last 

 Autumn (Oct. 6, 1872), but, as I suppose, neither of them was 

 seen. With the loss of its hero, our story would seem to come 

 to an end. I must ask your indulgence, however, for another 

 chapter. 



I suppose that each one of you has often seen a shooting star. 

 On a clear night you have seen a bright point of light travel 

 quickly across the sky, as though a star had been shot from its 

 place in the firmament. It may, if it was a large one, have 

 broken into sparks as it disappeared, or have left a cloudy train 

 along part of its path for an instant ; or perhaps it was so faint 

 even that you could not be quite sure that you saw anything. 

 Some of you have seen those shooting-stars by hundreds in 

 star showers. 



Until near the close of the last century, poets dreamed, and 

 other men guessed, about these objects, but knew nothing. 

 Two Grerman students, Brandes and 

 Benzenberg, found out, and told us, 8 - 



that these bright flights were in \/ 



the upper parts of the atmosphere. 

 From the two ends of the city a 

 track always appeared to be in the 

 same part of the heavens. But when 

 one went to a village many miles 

 away, a track was seen by the 

 two persons (at A and B, figure ^ , 

 8), in different parts of the sky. 

 Hence they were able to measure the 

 height of the shooting stars from the ground. 



We now know that these luminous paths are rarely less than 

 40 miles or more than 90 miles from the earth. We also know 

 that any shooting-star was a small body, of unknown size, per- 

 haps not larger than a pebble or a grain of coarse sand even, 

 undoubtedly solid, which has been traveling around the sun in 

 its own independent orbit, like any planet or comet. Its path 

 came within 4,000 miles of the earth's center, and so the small 

 body struck into the earth's atmosphere. Its velocity was so 



