186 05. cea: Ltowland—felatgve Wave-lengths 
angular measurement that the latter has little or no weight in 
comparison. 
This table is to be used in connection with my photographic 
map of the normal spectrum to determine the error of the latter 
at ary point. The map was made by placing the photograph 
in contact with the scale, which was the same for each order of 
spectrum, and enlarging the two together. In this way the map 
has no local irregularities, although the scale may be displaced 
slightly from its true position, and may be a little too long or 
short, although as far as I have tested it, it seems to have very 
little error of the latter sort., The scale was meant in all cases, 
except the ultra violet, to apply to Peirce’s absolute value and 
so the correction is generally negative, as follows: 
Approximate correction to the photographic map of the normal 
spectrum to reduce to latest absolute value. 
Strip 3200 to 33380___.___- Correction ---.----—.05 
SZ TORLON S23 Ome sees Laas Pe ey —'05 
SAT OutOnsMoOe sane eee Dem a es s 2 —-02 
G2 SEXO) 1K) EO aos S65 Oe A Ne aa — 10 
STS Oil CORI 3 Opener amen 6 iat Dis seer en —a6 
SV A0Vo to4330 ee ae Rene eee — "04 
a2 DO 4090. S255. 8 SE al ees Aas eae —'08 
fo 44 80)500 473022 eee SE ig coe ta eee ae —10 
4685 C0404 0s ee eae a pec ienaen, So 91 is} 
CASO COLO LS Om eae ase SORE ate ype —'14 
SS OOMO, bOO33 0a ease SS Soe eee ee —*15 
Cs PANES (H0), NG os bos s about... -—*05 
Soe DECOR DO Deere oy about.-.—‘04 
Coote OMCOn SO Omeeee ae Oe Tae ake yee —°20 
Peo LONto 400022 sae ene SEL Aad 94> yas eee — ‘14 
It is to be noted that the third spectrum of the map runs 
into the second, so that it must not be used beyond wave 
length 3200, as it is mixed with the second in that region. 
TABLE I, 
Coincidences. 
(2) (8) 6439°222 (4) 
7039°969 4691°516 4293-181 - 7240-868 
1027°658 4690:260 (9) 4824-243 
7023-676 5624°696 6439-922 4823°636 
5270-448 (6) o 7233-063 
6 4508402 (6) 
BON Ls 4501387 eee 4501:377 
4999-336 5624-696 Teeny 6750°332 
7027-627 5624°181 (4) 
5270°429 4496:990 (4)- 4691°517 
4215°627 (18) 4824°249 6027°665 
7023°632 6430°993 4823°630 7015°641 
