The Birmingham age-herald., 1918-07-07

g1on Of the sky, noting every shooting 1 star which appears within it.
 | His watch may last for hours, or even
 all night, and when he has become ex- Ipert in noting even the faintest shooting
 stars, he will probably see from 10 to | ~ traverse the region which he has | chosen to watch during each hour. In | the morning for few hours before sun rise the number seen is at least twice :ls | great as the number seen in the evening hours, because at the former time we are on the side of the earth which is in the front as it passes around the sun | With velocity of more than IS miles a second. Accordingly, we see all of the | meteors which the earth runs into while l Tn the latter case we are on the rear of the advancing earth so that we see only | those which collide with the earth by overtakiuy it. For this reason also the meteors seen in the morning move much ] more swiftly than those seen in the even- Ing. Their high velocity through our air consumes them much more quickly and raises them to a higher temperature. They thus usually appear of a bluisn color, while the slow-moving evening shooting stars are reddish yellow, and these latter usually trace much longer path among the stars before they are consumed
 w HeH d sHOOtlng star appears in the part of the sky which the observer is watching, it will move swiftly in any di- rection anc suddenly disappear. The student should note as carefully as pos sible the two points among the stars at which 1t appeared and disappeared and then, turning to the star atlas, he should find the positions (Right Ascension and Declination, of these points. He should also note the time by his watch. Any 1Ot fD %l,1 star it's magnitude and any peculiarity about it should be carefully added at the time the observation is made. Espc- cially should the observer note if trail is left, and if this persists, he should note by his watch how long this remains visible and also it's apparent motion, 9r drift among the stars. Such trails are sometimes visible for many minutes. and sometimes even for so long as halI an hour They are finally dispersed by air currents, which, at a height of 42 miles, have velocity of about 60 to 70 miles an hour. But puzzling feature of them is that they may remain Iuc,i- nous for 50 long a time, surrounded as they must be by so intense a cold. Doubtless, their light is of phospt or- escent nature, but it's source has not been as yet clearly explained.
 When the observer has determined
 
 manner described, he may find that some of them upon being extended backward, come together in one point or area of the sky. Thus in Figure 3, which shows many paths observed in the Leonid shower it will be seen that nearly all of the shoot ing stars have apparently shot out ward from the region marked A, though there are several observed on ic nio yyho cho they do not belong to the Leonid shower. The point A is called the Radiant Point and it is merely vanishing point of perspective. All of the shootingstar particles were moving around the sun in a great stream in paths which were nearly parallel to one another. We only see a small part of each path. be- cause it is only when the particle is moving through our air and is rem dered luminous by the great friction that it is visible to us This great stream of particles is in this case a long ellipse, passing about the sun and extending out into, space 1900 millions of miles, and because this
 stream intersects the path pursued by the earth we blow through it whenever the earth reaches the mart of the orbit where the stream is. This occurs about November 15.
 Though there are thus a few great streams which give rise to the we'll
 known shooting-star showers, there have been nearly 400 others which were discovered hy locating their ra- diant points as here described. Oh servations on the radiants of these are much to be desired When we consider that we have no way of on- serving any meteor stream unless It happens to intersect the path of the earth, the number of streams of p.r ticles continually passing around the sun. but which we have no means of discovering must be enormous. These almost innumerab1e meteor streams are an important part of the solar system. O,,~ lxnowledee of those in- tersecting the earth's path must