END-ON VIEWS OF GAS SPECTRA UNDER HIGH DISPERSION. 157 
Brought forward (numbers and) sums of intervals, (10)532 (10)1054 (10)1646 
e u = : ey i ) o (aa) Appearances; and standard- 
Eee Batt ! : 
Wave- | Wave- Wave- |  Wave- line adopted places, in 
length; | number ; length; j number in metrical wave-lengths, and 
tenth- ina British a British in British wave-numbers. 
metres. | mil-met. inch. inch. 
ee eee — — ar 
0-000, 
6066°3 | 164848 | 023,883 | 41,871 aie 42,030 Tube-C. 
18 {| 6066°3 | 1648°48} 23,883 | 41,871 aa 41,976 42,026 (str. orange) | > =41,789 
871 on 105 028 | 157 | 42,255 | 384 6078 
6011°8 | 1663°40| 23,669 | 42,250 42,301 42,419 
9{) 6010°3 | 1663°79 | 23,663 | 42,260 42,309 a 42,420 
255 305 | 50 419 164 | 42,638 | 383 
5957°3 | 1678°64| 23,454 | 42,637 42,685 42,809 
20 5956°9 | 1678°76| 23,452 | 42,640 42,694 42,741 42,801 
; 638 689 | 51 103 805 | 167 | 43,018 | 380 
5904°6 | 1693°59 | 23,247 | 43,017 43,069 43,179 an 
5904'2 | 1693-71| 23,245 | 43,020 | 43,073 43,099-133 43,184 Be oe ares 
018 071 | 53 116 98 181 | 163 | 43,400 | 382 Aaa, Sad 
5853°0 |1708°53| 23,043 | 43,397 43,448 43,564 } 
5852°2 | 1708°77 | 28,040 | 43,403 43,440 43,494-527 43,570 
400 444 | 44 510 110 567 167 | 43,780 | 380 i 
5801°8 | 1723°60| 22,842 | 43,779 43,829 43,940 = Hydrogen } 
| 5801°5 | 1723°68 | 22,841 | 43,781 43,840 43,871-905 43,946 (faint) | > =43,698 
780 834 | 54 888 108 943 | 163 | 44,158 | 378 | 3 5812°5 \ 
= 
5752°0 | 1738°53 | 22,645 | 44,159 44,208 44,323 < 
5752°1 | 1738°49 | 22,646 | 44,158 44,209 44,244-283 44,325 
158 208 | 50 263 105 324 166 | 44,531 373 |) 
5703°8 | 1753°22! 22,456 | 44,532 44,699 
5704-1 |1753°14 | 22,457 | 44,530 44,577 44,610-643 44,678 
531 46 626 95 688 | 157 | 44,888 | 357 
5657°9 | 1767°44 | 22,275 | 44,893 45,058 Gas-fi, Citr, } 
5659°0 | 1767°89 | 22,280 } 44,884 44,950 44,986 45,030 line 1, ( = 45,086 
888 62 98 044 156 | 45,250 362 { 5633°5 
5612°6 | 1781°71| 22,097 | 45,255 ' 45,404 45,619 Tube-C. 
5613°7 | 1781°36 | 22,109-| 45,231-61 a iss Citr. edge, = 45,289 
—22,094 250 154 369 5608 
___ Total (numbers and) averages of intervals, (18)52°33 (18)104°22 (19)163°47 
> 
| _ @) Double-notched band of a Nitrogen Serration.—The dotted lines a ae (H x) _ 
show how Ha and Naa, fall among the linelets of the ridged band in which OW! : H 
each of them occurs separately, inthe red and yellow portions respectively 
f the channelled field. Only measurements of the linelets a, b, 0’, ¢ of 
the flutings included in its range, are recorded in this Table. 
(>) An extreme red ray, possibly a new oxygen line (?), seen with prisms of moderate dispersion in an air-vacuum tube; as observed and 
measured in a paper on ‘‘ End-on Vision in Private Spectroscopy ” by Professor Prazzi SmyTu. 
(*) A fine close-membered cluster, disclosed by end-on vision at the extreme-red end of the spectrum in both of the Cyanogen and Nitrogen- 
dentoxide tubes. It consisted, when best exhibited and observed in them, of four not far from equidistant, about equally bright and exceedingly 
sharp lines, In one of the two measurements obtained of its positions before it lost its brightness in the tubes, it only showed three lines, by 
the loss apparently (as comparison with the four-line measurement seems to indicate) of its leading line. It forms at the red end of the spectrum a 
| gtandly protruding and'detached, somewhat distinctly formed, first linelet-group of the uninterrupted train of them there springing up. Its followers, 
or after-groups, though weak at first, soon brighten up into the long row of close flutings of the red-to-green Nitrogen serration. The observed 
| Wwave-numbers of its third and fourth lines, 34,134 and 34,237 to a British inch (or wave-lengths 7441°2 and 7423°1 tenth-metres) appear to agree 
yd a not quite precisely) with the average positions in the other groups, of the linelets marked in the above figure by the ridge-tops 
‘and d (?) 
_ (*) This is the first spectral line noted in Ancstrém and Tuauin’s Table. Although recorded there as a ‘‘ first line,” (a), its measure in 
| English wave-number is here ranged under the same group’s second line 2, with whose remeasured place it more nearly corresponds, The 
secondary pair 6b’, in fact, of this first-noted fluting (the next before that which comprises Lia, and the next but two before that in which Ha is 
included), a little outshines the leading line a, by blending together into a stronger blurred maximum of brightness at the beginning of the group. 
2 The varying intensities of the flutings are noted in the column of ‘‘ Appearances” as ‘‘maximum” and “minimum,” as they are given by 
| ANestrom and THAutn, and as they present themselves in the spectrum. Of the standard-lines noted in the same column, only Ha (faintly), 
| and edge-places of the three Tube-carbon orange and citron bands (strongly visible) were measured in the Nitrogen tubes themselves, comparison- 
spectra being used to show the places and to furnish micrometer-readings of the other standard lines entered in that column. 
i Ge te 
