2 H. A. Newton — Relation of the Orbits of 



The first and third propositions are limited strictly by their 

 terms to the meteorites from stone-falls actually witnessed, and 

 also represented by specimens in some one or more of existing 

 collections. The investigations that have led to them have 

 been limited to the same stone-falls This is not because any 

 line of separation is suspected to exist astronomically between 

 the stone-furnishing and the detonating meteors, or even be- 

 tween them and the shooting stars, but because, for manifest 

 reasons, any facts established about these stones have a greater 

 value than similar facts about meteors from which no stones 

 have been secured. 



About 265 observed falls are represented by specimens in 

 existing collections. The history of these falls I have searched 

 out with no little pains, so far as the material for such history 

 could be found in books accessible to me. Every direct state- 

 ment and every indirect indication which I have obtained 

 about the paths of these meteors through the air have been 

 carefully considered, and their meaning and value duly esti- 

 mated. The determination of the path of a stone-furnishing 

 meteor through the air is greatly aided by the fact that we 

 know at once one point of the trajectory, viz : the point where 

 the stone strikes the ground. To this fact may usually be 

 added another, viz : that some of the observations are by per- 

 sons near the place of fall, and hence their statements of direc- 

 tion, so far as we may trust them, have peculiar significance. 

 In individual cases it will be found that not much reliance can 

 be placed upon the asserted direction of the meteor's motion. 

 Eut when the results are all collated there is such a general 

 agreement in support of the first and third propositions set 

 forth above that I am very confident that they are true. 



The orbit of a meteoroid about the sun is wholly given when 

 we know these three things, the time when it enters the air, 

 the direction of its motion, and the velocity. The velocity 

 cannot be easily measured directly. But the connection be- 

 tween meteors and comets will be assumed as fully proven. 

 The velocity of the meteoroids (neglecting the increase due to 

 the earth's attraction), ought then to be that of the comets, at 

 the same distance from the sun. The greatest cometary ve- 

 locity at the distance unity is \/2, the earth's velocity being 

 unity. The smallest velocity for any known comet is that of 

 Encke's comet, which at the earth's mean distance from the 

 sun is V244. It seems safe, therefore, to assume that the 

 meteorites we are considering had velocities relative to the sun 

 not greater than 1414, nor less than 1-244. 



The direction of a meteor's motion through the air is to be 

 determined solely by the evidence of observers of the stone- 

 fall. This evidence needs to be carefully collated, especially 



