1869.] of August 18, 1868. 71 



Lockyer's new c Kne and the abnormal appearance of p. The one 

 above it shows the general appearance of his prominence spectra. 



This discovery is being actively followed up, and the Eev. 

 Father Secchi has already communicated to the French Academy 

 two papers on the subject in which Mr. Lockyer's discoveries are in 

 every respect confirmed. 



In the absence of detailed official statements from the principal 

 observers, it is difficult to sum up accurately the results of these 

 spectrum observations, although there is no doubt that the scientific 

 gains have been immense. All except Captain Haig directed their 

 spectroscopes to the long horn which forms so prominent an object 

 in all the diagrams given, and which appears to have been con- 

 nected with one of the solar spots. Major Tennant speaks of it as 

 a vast flame of incandescent hydrogen, magnesium, and sodium 

 vapour, and considering that all the lines of these elements were 

 seen by one or other of the observers during the eclipse, and that 

 Mr. Lockyer and Father Secchi have since proved the presence of 

 the hydrogen lines, there is little doubt that these three elements — 

 hydrogen, sodium, and magnesium — actually do exist in a gaseous 

 and incandescent state in the circumsolar atmosphere. 



Since the discovery that the red flames (as we are entitled to 

 call them now) can be examined at any time the sun is visible, the 

 extreme interest with which physicists have hitherto looked forward 

 to a total eclipse will be somewhat abated. It may, however, be 

 worth recording that, on the 7th August next, there will be a 

 total eclipse of the sun visible in North America. The path of 

 totality, about one hundred miles in width, will pass through 

 Alaska, lat. 60° 46-9' north, long. 68° 4-6' west of Washington, 

 on Saturday noon ; crossing British America, it will again enter 

 the United States territory near the head of Milk Eiver, long. 30° 

 W., pass through the south-west corner of Minnesota, crossing the 

 Mississippi river near Burlington, Iowa, the state of Illinois just 

 north of Springfield, and the Ohio river near Louisville. From 

 thence it will run, in a south-easterly direction, through the states 

 of Kentucky and North Carolina, and reach the Atlantic Ocean 

 near Beaufort, North Carolina, at about sunset. North and south 

 of this hne the eclipse will be partial throughout the United States. 



The American photographers are already organizing arrange- 

 ments to bring every available telescope into use on that occasion 

 for photographic purposes, and intend securing photograj)hs along 

 as many points of the path as possible. 



The writer, who has ah-eady had some experience in johoto- 

 graphing the phenomena of eclipses, the moon and sun, would 

 venture to make three suggestions in this respect. Firstly, that 

 attention should not exclusively be confined to the wet collodion 

 process, but that the daguerreotype and dry albumen process should 



