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SCIENCE. 



[N. S. Vol. XII. No. 292. 



ccelostat. Time called by Professor A. S. 

 Flint ; exposure of 2 and 3 operated by Dr. 

 G. S. Isham of Chicago ; signal for ex- 

 posure given by visual observation of flash 

 with 1 by E. B. F., who operated 4. 



Results: 1. The flash spectrum was visu- 

 ally observed in the yellow near D^ at second 

 and third contacts. The number of lines 

 seen, however, was not as large as might 

 have been expected ; some 12 or 15 were 

 seen in the small field employed. These 

 were broken by the prominences, and were 

 doubtless chiefly lines of the usual chromo- 

 spheric spectrum. No attempts at measure- 

 ments were made, as the object of the visual 

 observations was to flnd the instant for 

 making the exposures for flash spectra. 

 The dark lines of the cusp spectrum were 

 sharp and distinct 45 seconds before the 

 computed time of totality. A glance into 

 the eyepiece at the middle of totality showed 

 no coronal rings in the field, which did not 

 include the region of 1474 K. 



2. Objective train of three large prisms 

 (mean path of the rays in the glass was S 

 inches) . Five exposures were made, on two 

 plates, all of which were successful. 



(a) The two spectra of the cusps, taken 

 before and after totality, show many bright 

 (chromospheric) lines in addition to the 

 dark lines. The region covered by the plate 

 was necessarily limited, by the construction 

 of the plate holder, and includes only from 

 /. 4380 to ). 4025. Fifty bright lines were 

 measured on the second cusp spectrum. 



(6) The first flash spectrum shows no 

 continuous spectrum, but will furnish the 

 wave-length of many bright lines. Some- 

 thing over 100 lines appear to be measur- 

 able within the above limits. 



The second flash spectrum was overlaid 

 by a band of solar spectrum, the third con- 

 tact occurring some seven seconds earlier 

 than was expected and indicated by the 

 count. This plate, however, shows a large 

 number of bright lines, 275 having been 



measured on it by the writer between 

 )■ 4380 and I 4027. Young's list of chromo- 

 spheric lines contains 27 in that region. 



(c) The coronal exposure was of 30 sec- 

 onds, but could have been longer to ad- 

 vantage. The rings of Hy and Hd (chromo- 

 spheric) are strongly impressed, showing 

 the prominences, and next in intensity is the 

 strong chromospheric rings of wave-length 

 X 4078. Four other rings are seen in whole 

 or in part, the coronal ring at / 4231 being 

 next in intensity, although faint. It shows 

 none of the broken appearance which char- 

 acterizes the chromospheric rings. Another 

 ring of longer wave-length than the Hy 

 may also prove to be coronal. The continu- 

 ous spectrum of the corona is quite strong. 

 This plate has not yet been accurately 

 measured. 



3. The small concave grating, without 

 slit, was used for first and second flash. 



On the first some 70 lines (bright) are 

 shown between lZ/3 and HS ; on the second 

 about 110 in that region, with about 50 

 others less sharply in focus, chiefly on the 

 violet side of H5. 



4. With the limited time for exposure, 

 the sensitiveness of the plates, of the ' Ery- 

 thro ' brand was insufiicient to record the 

 flash spectra. The plate exposed for 60' to 

 the corona shows no impression, as was in- 

 deed expected. The spectrum of the cusp 

 ten seconds after totality shows some dark 

 lines and a few bright lines, and the second 

 flash spectrum is seen in traces. 



E. E. Barnard. The following prelim- 

 inary statement concerns the photographs 

 of the corona obtained by the Yerkes Ob- 

 servatory expedition to observe the total 

 eclipse of the sun at Wadesboro', North 

 Carolina, May 28, 1900. 



The weather conditions were as near per- 

 fect as possible. 



The most important instrument was a 

 61i-foot horizontal coelostat with au excel- 

 lent 6-inch photographic objective made 



