A. MATHEMATICS AND ASTEONOMY. 1 1 



masses are by his telescope resolved into filaments analogous 

 to the penumbral ones, being disposed in curves, and having 

 brighter extremities, as if their ends curled upward. Lang- 

 ley sees no evidence of crystalline forms, but judges rather 

 that we seem to look down through increasing depths of 

 transparent whirling vapor, visible objects growing fainter 

 till lost to sight at an unknown depth below the surface. 

 The striking forms seen in the solar atmosphere are, he thinks, 

 most nearly typified by certain rare types of cirrus clouds in 

 our own atmosphere. In very many spots Mr. Langley rec- 

 ognizes the movement of one stratum of solar atmosphere 

 over another. 4 D, IX., 192. 



AGREEMENT OF SECCHl's VIEWS WITH PEOFESSOR LANGLEY's. 



The very beautiful solar drawings published in the Amer- 

 ican and Italian journals by Professor Langley, of Allegheny 

 City, together with the announcement of the conclusions 

 reached by him from his study of the solar spots, has called 

 forth some remarks by Secchi, of Rome, in which the latter 

 seems to claim a certain amount of priority in respect to 

 the ideas of Langley, and to maintain that they agree 

 with each other to a very considerable extent. This, how- 

 ever, can only be true in case Secchi relinquishes certain of 

 his long-held theories, and it is, therefore, important to put 

 on record his conversion to the views of Professor Lamrlev. 



WHITE LINES IN THE SOLAR SPECTRUM. 



Mr. Hennessy writes, from Massorie, to Professor Stokes, 

 that he has observed in the solar spectrum certain white 

 lines for whose existence he is unable to account. He can 

 not think that these are due either to the instrument or to 

 the latitude of the station. The white lines in question can 

 not be described as absolutely white, yet they closely re- 

 semble threads of white frosted silk held in the sunlight. 

 They are best seen about noon. 7 -4, XLVIIL, 305. 



PHOTOGRAPHS OF STELLAR SPECTRA. 



Mr. Lockyer, in a recent lecture on spectrum photography, 

 gives great prominence to the admirable labors of Messrs. 

 Rutherford and Draper in New York City, stating that the 

 latter gentleman has not only taken the most perfect photo- 



