Intelligence and Miscellaneous Articles, 



479 



(say) 15° wide, extending from the N.W. to the E. No pulsations of 

 any magnitude were evident ; but a radiated structure was manifest. 

 The spectroscope (pocket, by Hawkins and Wales) was first turned 

 on the full moon, and an idea of the length of the spectrum obtained : 

 then with a wide slit it was turned on the aurora, and the following 

 sketch made, which was carefully verified, so that it represents 

 exactly what I saw. ^ 



M ? Blue. N 



The length M N is what I conceived to be the length of the spec- 

 trum given by my instrument under usual conditions. The violet 

 (extreme) rays seemed cut off ; and I saw, 1 st, a broad and bright red 

 band (R), 2nd, a black space equal in width to it (B), 3rd, a green 

 and bright band (G) nearly as wide, then a faint spectrum of diffused 

 light, and a bright line in the blue (1), then a bright line more re- 

 frangible but whose colour could not be definitely seen (2). The re- 

 lative distances for my instrument are kept in the drawing. I then 



o 



opened Angstrom's ' Spectre Normal,' and saw that he gave the auroral 

 line as in the yellow. I observed this green line again, and cannot 

 persuade myself that it was yellow. The black space I am sure of ; and 

 it was also seen plainly by an inexperienced person into whose hands 

 I put the instrument. The slit was then narrowed and turned on 

 the moon, and adjusted to give the Praunhofer lines most clearly. 

 The aurora by this time was fainter, and I can only be sure of a 

 bright line (green) with a suspicion of my former blue line. Opening 

 the slit again, the red band of the diffused-light spectrum was close 

 against the green bright line. The aurora then faded. I mention 

 this black space, as it is not what I expected to see from my reading 



o 



of Angstrom and Winlock. — Silliman's American Journal, Nov. 1872. 



CONTINUATION OF THE OBSERVATIONS RELATIVE TO THE PRE- 

 SENCE OF MAGNESIUM IN THE CHROMOSPHERE OF THE SUN. 

 BY M. TACCHINI. Palermo, July 30, 18/2. 



As a sequel to my previous note on this subject*, I take leave to 

 give some details on the subsequent observations. The frequency 

 of magnesium has been considerable till this morning, but with very 

 pronounced maxima and minima. It would be impossible for me at 

 present to make a complete report, which would require much time; 

 I shall confine myself to the truly extraordinary last period, that from 

 the 25th to the 30th of July. The following are the numbers of 

 degrees which express the distances, referred to the margin, of the 

 points where the magnesium was visible : — 



o ^ . o 



July 25 176 



„ 26 348 



„ 27 348 



July 28 348 



„ 29 348 



„ 30 258 



Phil. Mag. August 1872, p. 159. 



