280 HUBERT ANSON NEWTON. 



and 1885, as well as a trifling display in 1867, are related to the 

 orbit of 1852.* 



Assuming, then, that the meteoroids which we met on the 27th of 

 November, 1872, did not leave the immediate neighborhood of the 

 Biela comet before 1841-2, we seem to have the data for a very 

 precise determination of their orbit between those dates. The same 

 is true of those which we met in 1885. The computation of these 

 orbits, the author remarks, may possibly give evidence for or against 

 the existence of a resisting medium in the solar system. 



In his last public utterance on the subject of meteors, which was 

 on the occasion of the recent sesquicentennial celebration of the 

 American Philosophical Society, Professor Newton returns to the Biela 

 meteoroids, and finds in the scattering which they show in the plane 

 of their orbit the proof of a disturbing force in that plane, and there- 

 fore not due to the planets. The force exerted by the sun appears to 

 be modified somewhat as we see it in the comet's tails, where indeed 

 the attraction is changed into a repulsion. Something of the same 

 sort on a smaller scale relatively to the mass of the bodies appears to 

 modify the sun's action on the meteoroids. 



In 1888 Professor Newton read a paper before the National 

 Academy "Upon the relation which the former Orbits of those 

 Meteorites that are in our collections, and that were seen to fall, 

 had to the Earth's Orbit." This was based upon a very careful study 

 of more than 116 cases for which we have statements indicating more 

 or less definitely the direction of the path through the air, as well as 

 94 cases in which we only know the time of the fall. The results are 

 expressed in the following three propositions : 



1. The meteorites which we have in our cabinets and which were 

 seen to fall were originally (as a class, and with a very small 

 number of exceptions) moving about the sun in orbits that had 

 inclinations less than 90 ; that is, their motions were direct, not 

 retrograde. 



2. The reason why we have only this class of stones in our collec- 

 tions is not one wholly or even mainly dependent on the habits of 

 men ; nor on the times when men are out of doors ; nor on the places 

 where men live ; nor on any other principle of selection acting at or 

 after the arrival of the stones at the ground. Either the stones 

 which are moving in the solar system across the earth's orbit move 

 in general in direct orbits ; or else for some reason the stones which 



* It is a curious coincidence that the original discoverer of the December shower as 

 a periodic phenomenon, Mr. Edward C. Herrick, should have been (with a companion, 

 Mr. Francis Bradley,) the first to observe that breaking up of the parent body which 

 was destined to reinforce the meteoric stream in so remarkable a manner. See Amer. 

 Jour. Sci. , ser. 3, vol. xxxi, pp. 85 and 88. 



