; Om theDmMe Refraction ef Insulatino Fluid*. 
?-:■::'--::: .\v. 1 : 11 : :•;.; -.--- - : '. si: ~ _r -. .: variations :: 
rlerrri: i;-":l- :-.::■ ::::..-.: r 11" ^ :: :le sen of oil examined. 
In a certain description of petroleum, d y a: first increased with 
the increase of P, and then remained constant while P was 
------ 
In rape-seed oil the difference of phases of the light pola- 
rlr-rl -..:.. \\ 1 :,:. i :-r; •.- ::.!:. ::1.\: :: :l:e lir.-.-s :: elr::ri: ::r:-e 
was greater at the first moment alter the sudden entrance of 
tiie electric forces than subsequently. At :1 me the 
field appeared darkened for about half a minute. The phase- 
difference therefore con ariable and, on the a : 
the electric forces continuing, a constant portion. The former 
appears to arise from an electrical unequal expansion 
:il. in like zi:r_i:ir: - i:~V.e reir:. ::::- results from unequal 
It:'::::. 
7. : ; lien: —en: :: 1:~1 ".- iv:::.;-:::: :.:-:- very striking when 
from any cause the electric forces in the in - the insu- 
lating fluid undergo periodical variations and etime 
-.1 _:•:-": •: :: 1 i:;e:'s ::vc ens :-:r is Lisplaced a little 
- "__ . . _ : 
::" lie eleirr: =s ■'_■. n;r- ::• v. : .- ~ ; these startings :r 
pulsations. With cylindrical electrodes the dark streak in the 
fiabinet compensator then appeared displa same 
■-:.- :_■ ::. -_-.- : ".:. : :.:_ 1 ::;:e: : . - : -"_- ?ylinder. Ihe 
. :r_s:.. : - Z_ : :. .. Z : ::. re:se: ".= "1 Irerence : : : ::-:: vials 
: : St : n 1 :. — i:i Li_\L i : :v: 1- iri renees iid they reach 
the value ordinarily found for them without pulsations. At 
the same time numerous air-bu 1 from the 
fluid, and a clicking sound is heard proceeding from the ap- 
::.::.---. :1t :!::!_ :: ~l_i 1_ ::Z_s ..- :_r : ■: :ei:rial-_ifi^rence 
"iivvlv/is-es. 
In order to examine whether the mean index of refraction 
.:::>::-"::_ rl~: - :s :.!:-;: 1 ~:v electric f: a es. the fluid c :n- 
densers were inserted in an is*, in which 
two pencils of rays reflected fr ..ne-paralle. 
plates of equal thickr e and form a pure spectrum 
with Fraunhofer's lines, which 
ferenor- One of the pen : vlxTough the fluid 
::.-:! .-_t :vie: :::.:-: ie :'_e -rl-ivr: les. 
On the electrification of the fluid a displacement of the 
interference-streaks was ohe :. of an 
increase, and now in the direction of a diminution of the re- 
fraetion-inc _ vaves, 
-streaks. These wave- 
like displacements appear : periodic discha: _ 
Tffcp, Pogg. Asm, cxssii .. 
