THE SOLAR SPECTRUM AT THE DATE 1877-1878. 323 
Appee- PLACE- Differences. 
Colour of the ; ance by . f DATA, Chemical-origin-|} Concluded || ———————— 
Continuous Object Observed, generally a black, fixed ibe or| StaPhical ne from data trom WAVE. 3 | 2 
Spectrum at Fraunhofer Line. thickness | COMpara- -DERETONs Angstrom, NUMBER- || 22 S 
the Place. Gtiiries tive Rev Grating Nor-| Thalen, &c. PLACE, per || 32 § 
symbol. : mal Solar British Inch.]/ 52] 3 
Spectrum. ; 6A) 6 
Hazy line, 1 11:264 57 048 20 
Dok. ‘ : : : a ¢ 1 . 11°354 Manganese. 57 068 1 
Strong hazy line, . ; : ; 2 11420 Titanium. 57 081 
Hazy line, c : : : 1 11°507 57 100 oe 
Strong line, 3 11°583 Tron. 57 116 a8 
Faint hazy line, : ; 5 1 sk 11°635 Titanium. 57 127 tl 
Exquisite bands of beautifully graduated lines follow, thus :— 21 
Very fine line, . ; ; : : 0°5 oD) 11°730 (|| 57 148 
Tice Tino.) i ei ne oa | 11°750 7 111 ||? 
haze intervenes. | 3 
Fine line, ‘ 1:2 | 11°770 57 154 
haze intervenes. i 
Clear line, ch a at 2 11°798 ~ Titanium. | 57 161 
stronger haze intervenes. 4 11 
Strong line, . F ‘ 3 =| 11°849 Tron. 57 172 
stronger haze intervenes. | = | 8 
Strongest line, . 5 | =| 11886 Tron, | 57 180 
strong haze intervenes. 8 
Strong line, ihe eat | 11'915 Iron ? | 57 188 
weak haze intervenes. 4 
Fine line, 1 ie) 11:940 Wily bm, 192 
Very faint haze, 0°5 Ht 12°020 57 210 18 
Very fine line, . (Ra N59) 12°147 f 57 236 ze 
Fine line, 08 |. 12186 57 245 : 
Do. ea 12-207 57 249 
Clear line, 15 12°238 Manganese. 57 256 7 
Strong line, 2° | \ il 12°258 Manganese, | 57 260 4 
INDIGO. | Stronger line, a5 || al 12°286 pate | 57 266 6 
Do. 3 | 12°300 56 269 : 
i 6 
Strongest and darkest of all.| 5 J 12:332/57 274] Calcium. (57 275 
16 
Double line : 1st component, 2 I } 12°405 57 291 7 
2nd do. 2 iS Q)  12-435 57 298 a 
Meicentss .  . kel l 12°528 57 318 ae 
12 
Faint flat band : 1st side, 2 : 12°588 Ir 57 330 10 
2nd do. y) — 12°635 eae 57 340 18 
Fine line, 15 | 12°718 57 358 20 
Strong double line: 1st component, . 3 | 1 (} 12°804 Titanium. 57 378 20 
2nd do. é 3 | {| 12-905 Calcium. 57 898 
Fine line, i | 12:986 57 414 16 
Haze band : begins sharp, 1 ed, 13°045 57 429 15 
ends weak, 0°3 == 13-128 57 446 || 1° 
Fine line, j 13°340 57 492 = 
Do. : : : ; 1 | 13°385 Titanium. 57 501 hl 
Do. oS Oe eee ee ee | 13°433 57 512 
Very strong, black and 17 
hazy: Ist side, - . . 6 } 13°515 } 57 530), Irom and 57 529] 5 
2nd do. 13548 Manganese. § || 5'7 532 
1h. 10m. p.m. 
The field is now rather too dark, and is violet-coloured, approaching to lilac. On trying in place of present prisms 
8 and 6, Disp. =21°, the whiter pair 8 and 4, Disp. =14°, the field is instantly lighter and wer. 
And on trying the still more transparent pair 8 and 3, Disp. =10°, the field is still lighter, and a lighter and more 
cobalt blue, or verging back even to glaucous blue ; the actual spectrum-place, nevertheless, as tested by the last line, 
being absolutely the same all through. 
Similar, but mutatis mutandis, features having been noticed at the red end of the spectrum, it is plain that the 
colour has certain limits of change of place in the spectrum, according to illumination ; though spectral Jines have not. 
The limits, however, being very small, and not sensibly marring the general law for beginners with small dispersive 
powers, that colour and refrangibility march together. i 
Saturday, June 29, 9h. 30m. A.M. 
| Trou and ! | | 
Centre of thick hazy line, | 6 | | 6955 | 57 530 |Manganese. ||| 5'7 530} 12 
All the lines hereabouts are hazy, more or less. 
