OF  TEMPEEATTJEE  ON  THE  EEFEACTION  OF  LIGHT. 
891 
A. 
B. 
c. 
D. 
E. 
F. 
G. 
H. 
1-3284 
1-3300 
1-3307 
1-3324 
1-3347 
1-3366 
1-3402 
1-3431 
These  measurements  agree  very  closely  with  those  previously  published  by  Fraunhofek 
and  by  Powell. 
Ether'. — Anhydrous  ether  boiling  at  35°  C.  gave  the  following  results  * : — 
Tempera- 
ture. 
Refractive 
index  of  A. 
Refractive 
index  of  D. 
Refractive 
index  of  H. 
Sensitiveness 
per  5°  (D). 
Length  of 
spectrum. 
Dispersive 
power. 
5°C. 
10 
15 
20 
25 
30 
34 
1-3585 
1-3555 
1-3529 
1-3508 
1-3485 
1-3460 
1-3442 
1-3622 
1-3592 
1-3566 
1-3545 
1-3519 
1-3496 
1-3477 
1-3740 
1-3707 
1-3683 
1-3658 
1-3635 
1-3611 
1-3595 
0-0030 
0-0026 
0-0021 
0-0026 
0-0023 
0-0024 
0-0155 
0-0152 
0-0154 
0-0150 
0-0150 
0-0151 
0-0153 
0-0428 
0-0423 
0-0431 
0-0423 
0-0426 
0-0432 
0-0440 
The  following  measurements  of  the  principal  fixed  lines  were  obtained  at  15°  C.  : — 
A. 
B. 
C. 
D. 
E. 
F. 
G. 
H. 
1-3529 
1-3545 
1-3554 
1-3566 
1-3590 
1-3606 
1-3646 
1-3683 
Alcohol. — The  following  Table  represents  the  mean  results  of  many  experiments 
performed  with  absolute  alcohol.  In  order  to  prevent  the  alcohol  absorbing  water  from 
the  surrounding  atmosphere  during  the  course  of  the  experiments,  they  were  performed 
on  frosty  days  when  the  air  contained  no  moisture. 
Tempera- 
ture. 
Refractive 
index  of  A. 
Refractive 
index  of  D. 
Refractive 
index  of  H. 
Sensitiveness 
per  5°  (A). 
Length  of 
spectrum. 
Dispersive 
power. 
0°C. 
5 
10 
15 
20 
25 
30 
35 
40 
45 
50 
60 
1-3658 
1-3639 
1-3617 
1-3600 
1-3578 
1-3554 
1-3537 
1-3513 
1-3495 
1-3475 
1-3451 
1-3407 
1-3658 
1-3638 
1-3615 
1-3598 
1-3578 
1-3556 
1-3536 
1-3514 
1-3491 
1-3437 
1-3811 
1-3793 
1-3769 
1-3751 
1-3730 
1-3706 
1-3687 
1-3661 
1-3643 
1-3624 
1-3599 
1-3558 
0-0019 
0-0022 
0-0017 
0-0022 
0-0024 
0-0017 
0-0024 
0-0018 
0-0020 
0-0024 
0-0022 
0-0153 
0-0154 
00152 
0-0151 
0-0152 
0-0152 
0-0150 
0-0148 
0-0148 
0-0149 
0-0148 
0-0151 
0-0415 
0-0415 
0-0419 
0-0419 
0-0418 
0-0416 
0-0417 
0-0424 
0-0423 
0-0439 
The  refractive  indices  were  thus  determined  for  all  the  principal  fixed  lines  at  15°  C. 
A. 
B. 
C. 
D. 
E. 
F. 
G. 
H. 
1-3600 
1-3612 
1-3621 
1-3638 
1-3661 
1-3683 
1-3720 
1-3751 
Wood  Spirit. — The  purest  specimen  of  methylic  alcohol  which  we  could  obtain,  but 
which,  when  rendered  anhydrous,  had  too  low  a boiling-point,  was  examined  on  a day 
when  the  dew-point  was  as  low  as  0°-6  C. 
* This  Table  was  substituted  during  the  printing  for  a less  accurate  one. 
