112 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



1870. 



Of those observers who used integrating spectroscopes, Hammonb (p. 424) saw a spectrum in 

 whicli blue and violet were wauting, otherwise characterized by a red line — doubtless C. His in- 

 fitrunieut was a Browning's direct-vision spectroscope, and therefore presumably without a tel 

 escope. In all probability the observer's eye was not in the proper place ; at least such a supposi- 

 tion is the only plausible one which explains the anomalous observations. Of course, such an 

 explanation is only tenable if the spectroscope was used without a telescope. Abbay (p. 425) used a 

 spectroscope with two 45° prisms and an effective aperture of not far from i inch, supposing the 

 corona to have been i° in breadth. He saw 1474 K and F during the whole of totality. Pye (p. 

 427) used a spectroscope of about .§ inch effective aperture (according to the assumption just made) 

 with a 60° j)rism of dense glass. He observed, as did Abbay, the lines C, D3, 1474 K and F, but 

 unlike that observer, he saw them during the whole duration of totality. 



The remainder of the observers used integrating spectroscopes. Brown (p. 419), Burton (p. 

 437), Denza (p. 438), Lorenzoni (p. 444), and Nobile (p. 445) give no data as to their instru- 

 ments. The first named saw nothing; all of the others saw 1474 K. 



CARP3IEA.L (p. 415). Spectroscope 00° prism with /„ inch effective aperture ; power 5. At first 

 nothing was seen, but as the slit was widened three bright lines appeared. Clouds interfered 

 with accurate determination of places. 



Maclear (p. 420) does not describe his instrument. He saw five bright lines which he called- 

 C, D, E, b and F ; these were also seen, less intense, on the body of the moon. 



Perry (p. 423) leaves undescribed the essential constants of bis instrument, but as the Casse 

 grainian telescope which he used for an image lens had an angular aperture of only IgO it is highly 

 probable that the eilective aperture was too small for the moderately wide slit. He saw nothing. 



WiNLOCK (p. 430) employed a spectroscope with two prisms, otlierwise not described. The 

 observer recorded the positions of bright lines C, near D, 1474 K and F. He traced 1474 K to a 

 distance of 25' from the moon, ai.d the others nearly as far. No dark lines were seen though the 

 whole region, above F was most critically examined. 



Young (p. 432). Instrument, a spectroscope with 13 prisms of 55°, with effective aperture a 

 little less than i inch. The line 1474 K was traced from 10' to 13' from the sun ; C and D to 4' or 

 5', and even on the disc of the moon. No dai'k lines were seen, though carefully looked for. 



Harkness (p. 441) used the same apparatus which he had employed in 1S69 with much the same 

 result. 1474 K was estimated as extending 10' to 15' from the moon. Two less refrangible lines 

 were suspected. 



1871. 



At this eclipse the " prismatic telescope" was first used. The two observers who made use of 

 them employed widely different forms. 



LocKYER (p. 447) looked through five prisms of 45° each with the unassisted eye. He saw 

 three hydrogeu rings, together with a ring corresponding to 1474 K. The last-named was esti- 

 mated as the least bright. All were regarded as of equal width, not more than 2'. 



Eesmghi's (p. 462) instrument had an aperture of 4J inches, a single prism of about 13°, and 

 a power of 40. He saw three rings corresi)onding to C, 1474 K, and F. Of these the second was 

 the brightest and the last the faintest. The width of the green zone was estimated at C or 7'. 



Of those who used integrating spectroscopes Saxton (p. 500) and Tupman (p. 469) both saw 

 1474 K and both fail to describe their apjiaratus. 



