376 ANNUAL OF SCIENTIFIC DISCOVERY. 



The region of emanation has not great length in the great circle 

 through it and the sun. Hence the tangents to the individual orbits 



O B 



make nearly the same angles with the sun's radius vector. 



It follows that the elements of the individual orbits are nearly the 

 same, and hence the probable conclusion that the meteors form a ring 

 and not a disc of great breadth in its own plane. If the breadth is 

 very large, we must conclude that the great part of these orbits 

 which cut the earth's orbit belong to a limited zone, or ring, in the 

 disc. The mean velocity and direction of motion of the August me- 

 teors would give an elliptic orbit about the sun which would repre- 

 sent the ring. The velocity of a single member of the group, and the 

 mean place of the radiant, give approximate data for determining 

 this orbit. 



Calculations based on these data give for the ring's semi-major 

 axis, 0.84; for its ellipticity, 0.28; its perihelion distance, 0.60; its 

 inclination, 96, and the periodic time, 281 days. The thickness of 

 the ring is five to ten millions of miles ; for the earth, moving nearly 

 two millions of miles a day, is immersed in it during several days. 



A rude estimate of the number of individuals in the ring may be 

 formed. Several observers in one place in the morning hours of Aug. 

 10-11 see at least one hundred and fifty meteors, of which over three- 

 fourths are conformable. Assume the average perpendicular distance 

 of the paths of visible meteors from the observers to be not greater 

 than seventy-one miles. This implies that not less than one hundred 

 and twelve meteors pass through a circle of one hundred miles' radius, 

 the circle being at right angles to the relative motion. The velocity 

 is so great that the earth's attraction is not of much account in making 

 the number seen greater than the average throughout the ring. Re- 

 ducing 112 by the ratio v f : v", and calling the cross section of the 

 stream not less than the area of a circle whose radius is 2,500,000 

 miles, we have at least (2,500,000) 2 XH2y / -i- (100) V meteors 

 passing the node per hour. In 281 days, the periodic time, we have 

 more than 300,000,000,000,000 bodies for the whole August ring. 



* ' ^3 ^j 



New Views on the Nature and Origin of Meteorites. Prof. J. 

 Lawrence Smith, in an article contributed to Silliman's Journal 

 (Jan., 1861) on the Guernsey County (Ohio) meteorite, states that 

 he has, from the physical and chemical data collected by him respect- 

 ing meteorites, arrived at the following conclusions : 



1st. The light emitted from meteoric stones does not arise from 

 incandescence, but from electricity, or some other cause. 



2d. That the noise attending their fall is not that arising from the 

 explosion of a solid, but that it is by concussion of the atmosphere, 

 arising from the rapid motion of the body through it, or in part due 

 to electric discharge. 



3d. That meteoric showers are not the results of fragments from 

 the rupture of one solid body, but the separation of small and distinct 

 aerolites that have entered our atmosphere in groups. 



4th. That the black coating is not of atmospheric origin, but is 

 already formed when these bodies enter our atmosphere. 



I would call the attention of those engaged in the examination of 

 this class of bodies to the study of the true nature of their black coat- 

 ing ; also to the fact that observers at a distance often see these bodies 



