RECENT SOLAR RESEARCHES. 97 



nay, lie is enabled to measure (very roughly, of course) 

 the velocity with which these solar winds urge their 

 way through the chromosphere itself, in the neighbor- 

 hood of these spots. The progress of these hurricanes 

 is often indicated by the appearance of bright lines in 

 those parts of the spectrum where usually dark lines 

 are seen. 



Truly KirchhofPs discovery of the significance of the 

 spectral lines is bearing wonderful fruit ! Who would 

 have thought that researches carried on with a few 

 triangular prisms of glass on the light from such a 

 substance as sodium, the basis of our commonplace 

 soda, would lead to the result that solar tornadoes 

 could be watched as readily with the spectroscope as 

 in Galileo's time the sun-spots themselves could be 

 traced across the sun's disk with the telescope ? * 



(From the Spectator for July 2, 1870.) 



* I give this paper as it appeared in the Spectator. But there are 

 some points requiring correction. In the first place, the objectionable 

 word chromosphere (for chromatosphere) should be replaced by sierra. 

 Secondly, there is an error as to the absolute priority of Secchi in recog- 

 nizing the sierra. He went considerably beyond all others in the matter, 

 having not only reasoned upon, but seen and photographed the sierra, 

 and having furthermore found evidence as to its nature when studying 

 sun-spots. But Professors Grant and Swan, as well as Von Littrow, the 

 Imperial Astronomer of Austria, had recognized the existence of the 

 sierra before Secchi, and Leverrier had also independently arrived at the 

 same conclusion as Secchi, and at about the same time. I had not known 

 of some of these claims and had forgotten others when I wrote the above 

 paper. This will scarcely seem surprising when it is remembered that 

 the views of Grant, Swan, Yon Littrow, and Leverrier, had not been made 

 widely public as Secchi's had by being published in popular treatises 



