THE SOLAR SPECTRUM IN 1877-1878. 287 
But, strange to say, ANGsTRoM’s map has not got Nature’s red beginning of 
the Spectrum at all; though too that beginning contains the grandest group of 
lines throughout the solar spectrum’s whole extent, viz., the colossal band and 
series of great A. And again, all the latter end of his map, throughout its violet 
and lavender regions, is not only miserably cramped by the untoward qualities 
of the Wave-length scale adopted by him,—but is very imperfectly rendered 
therein, or thereupon, through the failure of his “ grating” to show that part of 
the spectrum well. To such an extent was this the case, that although I could 
improve little or nothing upon his grand map in the orange and citron regions, 
and in fact did not see the lines there so clear, strong and black as he has often 
engraved them,—yet in the violet regions the lines appeared to me so very much 
clearer, blacker, stronger, and both more numerous and more spread out than 
in his edition of them, that it was on that account often embarrassingly difficult 
to identify his few, thin, contracted lines and groups, amongst crowds of grander 
lines, all of them far more notable. 
Hence, if it be asked, in what may the present spectrum document hope to 
benefit existing knowledge—lI beg, with all deference to the labours of others 
with which I may be, up to the present time, unacquainted, to answer 
thus— 
(1st) In supplymg to ANnestrom’s Normal Solar Spectrum its proper and 
natural head-piece at the Red-end ; including not only “great A,” but certain 
other lines beyond it, seldom seen by any one. 
(2d) In adding to it a large number of very observable lines and groups of 
lines throughout the indigo, violet, lavender, and gray Spectral regions ; 
increasing ANe&sTRoM’s total number of lines from 1400, to 2000, nearly. 
(3d) In recording all the lines on a scale, equally absolute with Wave-lengths, 
but more naturally suited for spectral phenomena; because both increasing its 
numbers in the direction of increase of refrangibility, instead of against it; and 
giving also, on a scale of equal parts, 4 times as much standing room to 
lines at the violet end, as when cramped up by the Wave-length method. 
(4th) In furnishing an account from direct observations of the whole Solar 
Spectrum for a more recent date than any of the larger maps now before the 
public, viz., for the years 1877-8 ; it still being a question in science whether the 
Solar radiations alter in quality with time; and if so,in what manner and to 
what degree. 
ParvT IT. 
With the above remark I might close this introduction to the present 
| spectrum, but for one feature which came out so strongly day after day, as the 
observations proceeded, that it formed at last the chief and abiding impression 
