422 Mr. W. Huggins and Dr. W. A. Miller on the 



five lines, and in lead two bright lines were compared, but no 

 coincidence was found. 



Gold.— The strongest of the gold lines approximates closely 

 in position to one in the spectrum of the star, but it is probably 

 not coincident. 



Three of the strong lines of cadmium, two of silver, four of 

 mercury, two of barium, and one (the orange line) of lithium were 

 observed to be not coincident with any of the lines visible in the 

 star. In these comparisons, when barium was used, it was em- 

 ployed in the form of a nearly solid amalgam. 



The opening of the slit was maintained at the same width (not 

 more than the ^o tn °^ an i ncn ) f° r a ^ tne observations, both 

 with Aldebaran and a Orionis. In the case of the fainter star 

 which follows, it was very slightly widened. 



13. /3Pegasi. — The colour of this star is a fine yellow. In 

 the general arrangement of the groups, in the gradation of the 

 strength of the lines composing the groups, and in the absence 

 of the hydrogen lines, this spectrum, though much fainter, is 

 closely analogous with the spectrum of a Orionis, as figured in 

 the Plate. 



This star was carefully observed on many different occasions; 

 but the faintness of the star, and the unfavourable state of the 

 atmosphere on many of the nights of observation, did not per- 

 mit the same number of lines to be measured, or allow a com- 

 parison with an equal number of terrestrial elements. From 

 November 10, 1862, when twelve lines were observed, to the 

 present year, we have scrutinized the star carefully. 



Nine of the elements were compared with the spectrum of 

 /SPegasi. Two of these, viz. sodium and magnesium, and perhaps 

 a third, viz. barium, furnish spectra in which there are lines 

 which coincide with lines in the spectrum of the star. 



The spectra of iron and manganese were also compared with 

 that of the star, but the state of the atmosphere prevented any 

 certain conclusion. 



The lines in the spectra of nitrogen, tin, and mercury were not 

 coincident with any definite lines in the star-spectrum. Neither 

 of the hydrogen lines corresponding to C and F was present. 



At the end of the paper we have given a Table of such mea- 

 sures of the lines in the spectrum of this star as we can depend 

 upon. Although it appears to be as full of lines as either of the 

 preceding stars, the observations are attended with great diffi- 

 culty, owing to the insufficient amount of light. 



The absence in the spectrum of a Orionis, and also in the 

 spectrum of /8 Pegasi (which so closely resembles it in character), 

 of lines corresponding to those of hydrogen, is an observation of 

 considerable interest. It is of the more importance since the 



