and Astronomical Notices. 179 



tained somewhere or other ; though even if the day should 

 prove cloudy everywhere, a something will have been gained, 

 by habituating, so many persons to the strange and un- 

 earthly effects which come on so instantaneously, at the 

 moment when the last part of the sun vanishes, and a 

 merely large eclipse becomes a total one. 



The ominous sign of the sun becoming a dark patch in the 

 sky will certainly not be seen, but the general gloom comes 

 on over the face of the earth as suddenly and as super- 

 naturally, the clouds appear to blacken and descend, and 

 there is a darkness which may be " felt,'' as of a night which 

 will know no end. This may appear rather trifling when 



»read of, but the effect on those who have witnessed it, whether 

 scientific men duly prepared for it, or the vulgar wholly igno- 

 rant of the cause, or even brute beasts, is so excessive, that 

 they have one and all, more or less forgotten or neglected 

 their particular duties, in their admiration of, or their curi- 

 osity in, or their alarm at, the general effects. 



The principal observations to be made may be divided 

 under three heads, — astronomical, optical, and physical. 



The first, which would consist in determinations of the 

 exact instants of time of the beginning and end of the eclipse, 

 combined with measurements of the true latitude and longi- 

 tude of the place of observation, was most important in 

 ancient days for the improvement of the tables of the sun 

 and moon ; but now when we have their right ascensions and 

 declinations daily observed with powerful instruments in so 

 many observatories, we are no longer dependent on these 

 occasional opportunities. Differences of time during the 

 eclipse are more important than the absolute times, though 

 the closer these are known, the more convenient it may be 

 found afterwards in stringing together and comparing all the 

 isolated and perhaps unexpected little facts which may be 

 observed. 



I The second, or the optical, are not very easily separated from 

 the third or the physical, and are chiefly worthy of being ob- 

 served for the purpose of ascertaining what may be the pre- 

 cise limit between them, though doubtless many natural 

 philosophers may think them worthy of being pursued for 

 m2 

 i 



