THE ECLIPSE OF 1870. 55 



dispute to the last the significance of observed facts. 

 Unfortunately, in this instance, as in others, the 

 suggested doubts exercised a mischievous effect. It 

 was urged loudly by a few astronomers as Faye, 

 Feilitzsch, and others that the so-called prominences 

 were mere optical illusions, or else were but a species 

 of lunar mirage. Airy, Baily, the younger Struve, 

 and others, had recorded their experience in vain ; 

 fresh observations were called for ; and accordingly in 

 185T, and again in 1860, a host of skilful observers 

 devoted their energies to demonstrate what was in 

 truth a demonstrated fact the reality of the red pro- 

 tuberances. 



Yet the important eclipse of 1860 did not pass 

 altogether without profit. Too many, indeed, of the 

 observers who formed the celebrated ' Himalaya expe- 

 dition,' as well as of those Continental astronomers who 

 visited the path of the moon's shadow across Spain, 

 were led by the unfortunate doubts of Faye and others 

 to make useless observations. But the successful 

 photographing of the coloured prominences by De La 

 Kue and Secchi sufficed to convert what would other- 

 wise have been a gigantic failure into a success well 

 worthy of record. For the first time astronomers 

 possessed pictures of the prominences which were 

 beyond cavil or question. And further, since De La 

 Rue had been stationed in the west of Spain, while 

 Secchi had placed himself close by the eastern shore, 

 it had become possible to form an opinion of the 

 permanence or mobility of these strange objects. So 



