554 
Proceedings of the Koval Society of Edinburgh. [Sess. 
MF 2 3 H 2 0. 
NiCI 2 6 H 2 0. 
NiBr 2 3 H 2 0. 
NiI 2 6 H 2 0. 
c . 
A. 
A . 
c . 
A. 
A . 
c . 
A. 
A . 
c . 
A. 
A . 
•10 
?-226 
7-16 
•40 
? *226 
1*79 
•040 
?233 
9-10 
•00004 
? -227 
27000 
•14 
? "228 
5-12 
•233 
1-20 
•10 
•235 
7*16 
? ’233 
18000 
? -230 
3-42 
•244 
•61 
•237 
5-96 
•0001 
•239 
10000 
•244 
1-74 
•284 
•07 
•20 
•240 
3-58 
•0002 
•242 
5413 
•284 
•20 
•325 
•07 
•40 
•248 
283 
•0001 
•243 
4790 
•363 
•20 
•344 
•69 
•257 
2-40 
•001 
•250 
1100 
•367 
1-07 
•353 
1*27 
•267 
2-40 
•252 
959 
•369 
1-94 
•357 
1-86 
•271 
2-83 
•253 
716 
•377 
3*62 
•362 
2-47 
•287 
2-90 
•002 
•254 
566 
•383 
5-32 
•366 
2*90 
•289 
2-47 
•001 
•256 
364 
•393 
7-05 
•20 
•370 
3-72 
•292 
1-86 
•002 
•259 
239 
•10 
•403 
7-44 
•378 
4-94 
•296 
1-27 
•265 
239 
•14 
•410 
7-05 
•380 
5-80 
•304 
•67 
•001 
•268 
364 
•420 
5*63 
•10 
•382 
6-24 
•314 
•07 
•002 
•271 
566 
•423 
3-94 
•399 
7-44 
•343 
•07 
•001 
•278 
744 
•433 
2-26 
•407 
7*44 
•352 
•69 
?-290 
987 
•436 
1*38 
•418 
6-69 
•364 
1-27 
•298 
744 
•20 
•421 
5*16 
•366 
1-86 
•305 
| 392 
•429 
3-94 
■368 
2-47 
•312 
272 
•432 
2-76 
•369 
2-90 
?-315 
149 
•40 
•437 
1-38 
•20 
•370 
3 72 
? *335 
149 
•448 
•79 
•378 
4*94 
•336 
392 
?-470 
•18 
•379 
5-80 
•002 
•337 
580 
•10 
•387 
6-24 
•001 
•349 
744 
•393 
7-44 
•002 
•370 
580 
•04 
? ‘407 
9-80 
•001 
•374 
592 
•10 
•416 
7-89 
•002 
•395 
253 
•418 
6-69 
•005 
•410 
197 
•421 
3-16 
•420 
158 
•40 
•425 
2-58 
•01 
•429 
120 
•434 
1-38 
•445 
103 
•443. 
•79 
•454 
79 
•472 
55 
•503 
32 
The values of A in the above tables have already been plotted as 
functions of A in the third paper of this series. In these curves the results 
obtained by the thermopile, spectrophotometer, and photographic photo- 
meter all join on quite well. It is, of course, to be remembered that where 
the values obtained by the different instruments overlap, each of these 
instruments is getting out of its proper region and is hence working with 
less than its usual accuracy. The sets of the cobalt and nickel curves are 
drawn to the same scale. 
It is seen by examining these curves that the molecular extinction 
coefficient is, to a first approximation, apparently an additive property, at 
least for the salts examined. In each of the cobalt salts the same bands 
occur at A^' 510 /x and at the infra-red end of the spectrum. These bands 
