SOMETHING WRONG WITH THE SUN. 119 



other like circumstances. It was while engaged in 

 some of the more difficult and delicate of these tasks 

 that Tacchini noticed the strange occurrence now to 

 be described. 



' I have observed a phenomenon,' he says, ' which is 

 altogether new in the whole series of my observations. 

 Since May 6, I had found certain regions in the sun 

 remarkable for the presence of magnesium.' Some of 

 these extended half-way round the sun. This state of 

 things continued, the extension of these magnesium 

 regions gradually growing greater, until at length, on 

 June 18,' says Tacchini, 'I was able to recognise the 

 presence of magnesium quite round the sun that is 

 to say, the chromatosphere was completely invaded 

 by the vapour of this metal. This ebullition was ac- 

 companied by an absence of the coloured prominences, 

 while, on the contrary, the flames of the chromato- 

 sphere were very marked and brilliant. It seemed to 

 me as though I could see the surface of our great 

 source of light renewing itself.' While this was going 

 on Tacchini noticed (as had frequently happened before 

 in his experience) that the bright streaks on the sun 

 which are called faculge were particularly brilliant 

 close to those parts of the edge of the disc where the 

 flames of the chromatosphere were most splendid and 

 characteristic. The granulations also, which the as- 

 tronomer can recognise all over the sun, when a large 

 telescope is employed, were unusually distinct. 



Tacchini concludes (and the inference seems just) 

 that there had not been a number of local eruptions of 



