284 J. H. Long—Indices of Refraction of Compound Ethers. 
n—1 n—L n—1 
SEB ne ali [ 
ria S eCay eps | +. |e Ge 
PROPYL ISOBUTYRATE. PROPYL VALERATE. 
130 d) = °89299 M= 144 d, =°8809 
iY = 2 
19 | ‘8748 | 1°3964 | *4531 | 58°90 18 | "8652 | 1°4046 | °4676 | 67°34 
20 | *8738 | 1°3959 | *4531 | 58°90 19 | -8643 | 1°4041 | °4676 | 67°33 
21 | -8728 | 1°3955 | -4531 | 58°90 20 | *8634 | 1°4036 | °4675 | 67°32 
22 | *8719 | 1°3950 | °4530 | 58°89 21 | -8626 | 1:4032 | 4674 | 67°31 
23 | °8709 | 1°3946 | °4531 | 58°90 22 | :8617 | 1°4028 | -4674 | 67°31 
24 | °8699 | 1°3941 | °4530 | 58°89 23 | -8608 | 1°4023 | 4674 | 67°30 
25 | °8690 | 1°3937 | -4531 | 58°90 24 | -8599 | 1°4018 | °4673 | 67°29 
ISOBUTYL ISOBUTYRATE. - ISOBUTYRATE. : 
M=144 d,)=°87496 =158° de. ee 
19 | *8584 | 1°40 4663 | 67°15 18 sca 408 4 75°05. 
20 | *8575 | 13999 | -4664 | 67-16 19 | -8589 | 1:4080 bb 75°05 
21 | -8566 | 1°3995 | -4664 | 67°16 20 | -8580 | 1:4076 | -4751 | 75°06 
22 | 8557 | 1°3991 | -4664 | 67°16 21 | -8571 | 1:4072 | -4751 | 75°07 
23 | 8548 | 1°3986 | -4663 | 67°15 22 | -8562 | 1:4068 | 4751 | 75°07 
24 | -8539 | 13982 | -4663 | 67°15 23 | -8553 | 1:4063 | -4750 | 75°06 
25 | 8530 | 1:3978 | -4663 | 67°15 24 | -8544 | 1:4059 | -4751 | 75°06 
25 | -8535 | 1-4055 | 4751 ! 75°07 
ISOBUTYL VALERATE. 
‘ Ad 
"8513 14039 ‘4745 | 74:98 
-1. : Shia ee 
that the constancy of on is attained in eight cases, while in 
an equally great denber itis not. An attempt to connect this 
Lede with others of the same bodies has not been suc- 
essful. 
An opportunity is afforded by the above experiments of com- 
in which A is the coefficient of an and B that of dis- 
persion. For the wave length of the line D, I have used the 
mean value given by Wiillnes,t expressed in ten- thousandths 
of a millimeter, 4p) =5-893 
From Landolt I take 
Methyl beh A = 1°37879 B= 0°35077 
Kthyl but A = 138580 B=0 
sete d. rhage eemten saves, vol. ii, p. 150. 
where i values for A and B are given. 
+ Sakebich, chee hy ii, p. 136, 
ee Si on ig aE ea a 
