290 



SCIENCE. 



[N. S. Vol. XV. No. 373. 



•observations made by Piazzi at Palermo 

 between 1792 and 1813. Particular atten- 

 tion was directed to only one of the many 

 devices which have been applied for 

 shortening the computations whereby al- 

 ready the work is two years ahead of the 

 schedule outlined at the beginning of the 

 undertaking, that device being the use of 

 specially constructed table of limiting- 

 values instead of such logarithm or anti- 

 logarithm or other tables as appear inprint. 

 Illustrations of these special tables and 

 their application and data as to the per- 

 centage of time saved by their use were 

 also given. Another one of the devices has 

 already been published in Astronomical 

 Journalj'No. 498 (XXI. : 143-4) , and a num- 

 ber of others, of which mention was omitted 

 for lack of time and the lantern slides 

 which had been designed (but unexpect- 

 edly delayed) for their proper exposition 

 will be put into print at some future date. 



Observations of Meteors, November 13-16, 



1901: J. K. Rees. 



As in previous years, I observed with 

 Mr. Charles A. Post from his observatory 

 at Bayport, Long Island. We arranged 

 (1) to photograph meteor trails with four 

 cameras mounted on the equatorial which 

 was driven by an excellent clock, (2) to 

 count the meteors and (3) to record in- 

 dividual meteors which exhibited striking 

 peculiarities. 



1. The equatorial and cameras employed 

 are shown in Plate II., Popular Astron- 

 omy (No. 82), February, 1901. 



The apertures and focal lengths are given 

 in the following table: 



PHOTOGRAPHIC EXPOSURES. 



Nov. 13. 12:00 to 18:00 (Eastern Standard 

 time). A number of experimental plates were 

 taken but no effort was made to photograph me- 

 teors, as so few were seen. 



Nov. 14. 11:20 to 12:24. Exposed the Goerz 

 lens pointed at the belt of Orion. 13:15 to 14:05. 

 Exposed all the cameras pointed as follows: 

 Willard and Anthony lenses at Proeyon, Goerz 

 lens at belt of Orion, and Darlot lens at /z and 

 £ Leonis. At 15:00 the sky clouded but cleared 

 again at 15:30. 15:42 to 16:30 all cameras were 

 exposed. The Willard and Anthony on e Leonis, . 

 the Goerz on f^ t, (5 Hydrae, and the Darlot on 

 IJrsa Major. 



The clouds began to spread over the sky 

 again, and in a short time it was impossible 

 to see a star, later it cleared. Observers 

 then confined their attention to counting 

 and observing the 'meteors. 



Nov. 15. 11:45 to 13:00. Exposed all cam- 

 eras. Willard and Anthony lenses on Pollux, 

 Goerz lens on Proeyon, and Darlot lens on y 

 Geminorum. 14:35 to 15:45. Exposed all cam- 

 eras. Willard and Anthony on f Leonis, Goerz 

 on Regulus, and Darlot on a and /i Leonis Minoris. 

 Clock did not work as well as usual. 16:01 to 

 17:00. Willard lens was omitted. The other 

 cameras were pointed as in the preceding expo- 

 sure. 



Mr. Post developed all the plates. The 

 plates taken on November 14 show a num- 

 ber of trails. Quite a remarkable meteor 

 trail is shown on the plates taken with the 

 Willard and the Anthony lenses between 

 15 :42 and 16 :30. The notes given under 

 ' Record of Individual Meteors ' seem to 

 show that this meteor appeared at 15 :58. 



2. Count of Meteors. 



Only during the night of November 14 

 was any careful attempt made to count. 

 Miss Edith Post and Miss Greenough ob- 

 served the eastern slg^ looking toward the 

 radiant. At first both observed the same 

 part of the sky, but after 38 had been 

 counted Miss Greenough observed the 

 southeastern sky from the line from the 

 radiant to the zenith, and Miss Post ob- 



