A LARGE METEOR TRAIL IN THE FIELD WITH FINE NEBULÆ. (Photo, Yerkes Observatory.)
During the last half century meteors have been pretty systematically observed, especially by the astronomers of Italy and Denning of England, so that several hundred distinct showers are now known, their radiant points fall in every part of the heavens, and there is scarcely a clear moonless night when careful watching for meteors will be unrewarded. Besides November, the months of August (Perseids), April (Lyrids), and December (Geminids) are favorable. Following in tabular form is a fairly comprehensive list of the meteoric showers of the year, with the positions of the radiant points and the epochs of the showers according to Denning:
RADIANT POINT
| Name of Shower | R. A. | Decl. | Date of Shower |
| Quadrantids | 230° | +53° | Jan. 2-4 |
| Zeta Cepheids | 331° | +56° | Jan. 25 |
| Alpha Leonids | 155° | +14° | Feb. 19-March 1 |
| Tau Leonids | 166° | +4° | March 1-4 |
| Beta Ursids | 161° | +58° | March 13-24 |
| Lyrids | 271° | +33° | April 20-22 |
| Gamma Aquarids | 338° | -2° | May 1-6 |
| Zeta Herculids | 246° | +29° | May 18-26 |
| Eta Pegasids | 330° | +28° | May 30-June 4 |
| Theta Boötids | 213° | +53° | June 27-28 |
| Alpha Capricornids | 304° | -12° | July 15-28 |
| Delta Aquarids | 339° | -11° | July 25-30 |
| Perseids | 45° | +57° | Aug. 10-12 |
| Omicron Draconids | 291° | +60° | Aug. 15-25 |
| Zeta Draconids | 262° | +63° | Aug. 21-Sept. 2 |
| Piscids | 348° | +2° | Sept. 4-14 |
| Alpha Andromedids | 4° | +28° | Sept. 27 |
| Epsilon Arietids | 40° | +20° | Oct. 11-24 |
| Orionids | 92° | +15° | Oct. 17-24 |
| Epsilon Perseids | 61° | +35° | Nov. 5 |
| Leonids | 150° | +23° | Nov. 13-15 |
| Epsilon Taurids | 64° | +22° | Nov. 14-25 |
| Andromedids | 25° | +43° | Nov. 17-23 |
| Beta Geminids | 119° | +31° | Dec. 1-12 |
| Geminids | 108° | +33° | Dec. 1-14 |
| Alpha Ursæ Majorids | 161° | +58° | Dec. 18-21 |
| Kappa Draconids | 194° | +68° | Dec. 18-28 |
The year 1916 was exceptional in providing an abundant and previously unknown shower on June 28, and its stream has nearly the same orbit as that of the Pons-Winnecke periodic comet. Useful observations of meteors are not difficult to make, and they are of service to professional astronomers investigating the orbits of these bodies, among whom are Mitchell and Olivier of the University of Virginia.
CHAPTER XLIII
METEORITES
Meteorites, the name for meteors which have actually gone all the way through our atmosphere, are never regular in form or spherical. As a rule the iron meteorites are covered with pittings or thumb marks, due probably to the resistance and impact of the little columns of air which impede its progress, together with the unequal condition and fusibility of their surface material. The work done by the atmosphere in suddenly checking the meteor's velocity appears in considerable part as heat, fusing the exterior to incandescence. This thin liquid shell is quickly brushed off, making oftentimes a luminous train.