15i Scientific Intelligence. 



sion or permanent atttraction sufficient to change the orbit alto- 

 gether, not in kind, but in a steady change, throwing them into a 

 new orbit with a new period, and thus scattering them. 



What that added force must be, we cannot very well tell, be- 

 cause it differs according to the place in the orbit where the dis- 

 integration takes place. If that disintegration takes place near 

 the sun, it is one thing ; if it takes place near Jupiter, it is an- 

 other. It looks more to me as though there was a disintegration 

 all along the line of the comet's orbit, giving us small particles 

 with all sorts of loads of electricity and all sorts of differences of 

 central attraction and differences of orbits, and thus they get 

 widely scattered so as to give us the showers a long distance 

 from the comet itself. The maximum amount of this change 

 would have to be something like the tenth part, possibly, or some- 

 thing less than that. I should think that all the phenomena of 

 the meteoroids could be explained by a change amounting to 

 one-tenth ol the attraction ; that is, if the small particle carries a 

 load of electricity such as to diminish the attraction to say nine- 

 tenths of the original attractive force of the sun, or increase it to 

 eleven-tenths, it will explain the phenomena. 



If that is the explanation, we come to this further conclusion 

 of interest, that the space through which these comets move is 

 not such that the electricity which the particle carries can be 

 lost. Another practical point would be that, in the discussion of 

 the separation of these comet masses that through the telescope 

 we see going on as the comets pass the sun, there might fairly 

 be introduced an unknown correction of the force of central 

 attraction. 



2. Photographs of August and December Meteors. — At the 

 Yale Observatory I)r. Elkin made trial in August last to deter- 

 mine whether, with a reasonable amount of labor, tracks of meteor 

 flights could be secured upon photographic plates. On the even- 

 ing of Aug. 9th, he exposed three plates. The camera had a six 

 inch lens of thirty-two inches focus. This instrument had been 

 purchased and presented to the Observatory by Mr. Cyprian S. 

 Brainerd of Brooklyn who was interested in the experiments. It 

 was attached to the mounting of the eight-inch equatorial and 

 directed as nearly as convenient to the radiant in Perseus. The 

 total time ol exposure was four hours, and during the period 

 careful watch was kept to note the time, etc. of any meteors cross- 

 ing that part of the heavens which would appear on the plate. 

 Three meteor tracks were secured, one of which was very bright 

 and left on the plate a line nearly six degrees long. This is a 

 true Perseid, as was one of the other two tracks. 



On the same evening Mr. John E. Lewis of Ansonia exposed 

 plates in a stationary camera, and the brightest of the three 

 tracks was secured on one of his plates. A provisional computa- 

 tion shows that this meteor first begun to print its path on the 

 Observatory plate at a height from the sea-level of 68*0 miles. 

 It ceased to print when it was 51*65 miles high. The length of 



