1869.] of Aur/ust 18, iSGS. 65 



see at first, and couseqiiently the lines would be diffused some- 

 what ; still I think I should have seen them. The prominence I 

 examined was a very high narrow one, almost, to my eye, like a bit 

 of the sun through a chink in brightness and colour (I could see 

 no tinge of colour), and somewhat 2dgzagged, like a flash of light- 

 ning. It must have been three minutes high, for it was on the 

 preceding side of the sun near the vertex, and was a marked object, 

 both in the last photo-plate just before the sun reappeared, and to 

 the eye." 



The French observers seem to have been very successful. M. 

 Janssen, who was furnished with spectrum apparatus of a perfect 

 descrijDtion, describes the phenomena in the following manner: — 

 "Soon the disc of the sun appeared reduced to a thin luminous 

 crescent. Our attention was redoubled. The jaws of the spectrum 

 apparatus attached to the six-inch telescope were rigorously kept 

 in contact with that portion of the lunar limb which was about to 

 extinguish the last rays of the sun, so that the slit would be led by 

 the moon herself into the lowest regions of the solar atmosphere 

 when the two discs were tangent. The light disappeared aU at 

 once, and the spectral phenomena changed at the same time in a 

 very remarkable manner. Two spectra, formed of five or six very 

 brilliant lines, red, yellow, green, blue, violet, occupied the field of 

 view, replacing the solar spectrum which had just disappeared. 

 These spectra, about a minute in height, corresponded ray for ray, 

 and were separated by a black interval, in which I could distinguish 

 no appearance of a brilliant line. The finder showed that these 

 two spectra were due to two magnificent jDrotuberances which 

 shone out to the right and to the left of the line of contact where 

 extinction had just taken place. The preceding observation shows 

 directly : — 



" 1. The gaseous nature of the protuberances (briUiaut spectral 

 rays). 



" 2. The general simihtude of their chemical composition (the 

 spectra corresponding ray for ray). 



" 3. Then- chemical nature (the red and blue rays of their 

 spectra were decidedly c and f of the solar spectrum, characteristic 

 as is known of hydrogen gas)." 



The observing party at Wah-Tonne appeared to have been even 

 more successful than M. Janssen, if we may judge from the number 

 of fines seen and identified. M. Eayet had charge of the spectrum 

 apparatus, which consisted of a telescope with a silvered glass mii-ror 

 20 centimetres in diameter, mounted equatorially for the latitude 

 of the station, and of a direct vision spectroscope. The latter instru- 



VOL. VI. F 



