728 METEORIC STONES AND SHOOTING STARS. 



OTHER PERIODS. 



Schiapparelli cites a shower whose point of radiance is in the Northern 

 Crown, and time April 30th to May Ist. Prof. Daniel Kirkwood has deter-, 

 mined the period of this display to be about seven years, and thinks that it 

 corresponds with the following list of displays : 



April 9 A. D. 401 



" 17 " 538 



" 17 " 839 



April 17 A. D. 927 



" 18 " 934 



" 16 " 1009* 



August Meteors. — Francis Bradley in going from Davenport, Iowa, to 

 Chicago, 111., August 9 and 10, 1858, observed 128 shooting start, whose 

 radiant point was at or near Perseus, f 



Prof. Twining observed at New Haven, Conn., August 10, 1861, at 11^ 

 p. m., a meteor beginning near (Epsilon) Cygni, which appeared very bril- 

 liant for 12 seconds. Mr. Herrick says, we were startled by a brilliant 

 flash, immediately followed by a bright phosphoric bar, the meteor having 

 suddenly vanished, which was visible for 20 seconds, thus indicating a visible 

 track of 33 miles and altitude of 70 and 54 miles, with a velocity of 26.6 miles' 

 per second.f 



On 10th December, 1862, at lOJ to 11 p. m., a half dozen meteors were 

 seen at Philadelphia, apparently radiating from Castor and Pollux. The 

 next morning, from 4 to 4| a. m., a few more were seen also, all radiating 

 from the same point. 



METEORIC STONES. 



We have thus far been speaking of Meteorites as bodies having some 

 definite motion. Bolides or Aerolites are reckoned by some persons to be 

 governed by the same laws and to have periodic revolutions, but others, 

 and even our best scientific men, choose to think difi'erently. Investigations 

 prove that the laws of crystalization aff'ecting them are the same as those 

 affecting terrestial matter. || Thus we find pyroxene, olivine, chrome iron, 

 angite, &c., as constituents of meteoric bodies. Their form is very irregu- 

 lar and of various shapes, going to prove that the individual meteorites 

 have not always been cosmical bodies, for otherwise their form would have 

 been spherical or spheroidal. They must, therefore, at one time, have 

 formed part of a larger mass. 



Sulphurets and phosphurets of metals are also found in the interior of 

 the mass, arranged in nodales completely separated from the mass. || 



Meteoric stones ma}^ be (1) metallic, (2) stony, (3) mixed. The rocks or 

 minerals of meteorites are not of a sedimentary character, nor such as are 

 produced by the action or agency of water. The stony meteorites all have 

 a dark colored coating, which has been formed uj)on them after they en- 

 tered our atmosphere. Metallic iron alloyed with more or less nickel and 

 cobalt is of almost constant occurrence in meteorites. The existence of this 

 highly oxydizable mineral in its metallic condition is a positive indication 



* American Journal, July, 1872. f American Journal, November, 1853. 



t American Journal, November, 1861. 



II Dr. J. L. Smith, Scientific Researches, p. 285 



