SEP.IRATIOS O F OIL FROM THE SURFACE O F WATER
173
ON THE S E P A R A T I O S OF OIL FROM THE SURFACE OF K A T E R GEORGE ASTOSOF'F Department of Chemistry, F o r d h a m Universitv, S e w I'ork, N e w Y O T ~ Received M a r c h 1.9, IO@
When two immiscible liquids are placed in contact with one another, the lighter liquid will not spread and float in the form of a lens on the heavier liquid if its surface tension is substantially higher than that of the lower liquid, for example, in the case of a drop of n-ater on carbon tetrachloride. If, hon-eJ-er, a drop of oil is placed on the surfacc of water, the oil in most cases will spread on t,he surface of the rater and form such a thin layer that its removal \vi11 be difficult. This takes place because the oil has a lon-er surface tension than water. This problem gains in importance a t the present time in view of the fact, that enormous amounts of oil ~11.e k i n g spilled on the surface of the seas. Pollution of water in harbors is quite :I problem in itself. Considerations such nu the a1x)T.e slioii. that oil could be easily collected if it were possible to incre its surface tension sulistantially. Such a possibility suggests itself as a result of ohwvations on tlic behavior of pon-ders in a medium brought into a state ot rotation. Thus, if one rotates a saturated solution of Rmmonium chloride in u.hich ronie finely divided ammonium chloride is distributed, the latter concentixteu itself into a planetary body'. This can be done in a cylindrical glass ve.wel, in ishich the liquid is stirred hy cireular movements of a glass rod. I t is thus olxiuiis that, as a result of rotation, an attractive force has been generated which caused the collection of suspended matter into a planetary system. Similar effects hai-e been olwervecl with finely divided carbons suspended in liquids. -4similar esperinient has been performed with 11-ater and oil spread over its surface in the form of a thin layer (see figure l j . In this Case, the esperinient was done in a large basin. The stirrer, driven electrically, n-as inserted into i t ; the speed was controlled by means of a slide rhwstnt. The blades of the stirrer were bent so as to give a gentle pull inn-ard. A4tInoclerate stirring speed the oil collected around the axis in the form of a planetary body. Increase in speed a t first fai-oied the formation of the planetary body, but aftern-ards the sphere began to flatten out and showed a tendency to form a Saturnian ring. Hon-ever, the condition not being ideal, further increase in the speed of rotation resulted in the formation of moons, and finally the system disintegrated. Thus it is Seen that rotation causes such a n increa.w of tlie inn-3rd pressure and surface teiision that tlie oil ivhich iiormally spreads on the surface of the water \vi11 organize itself into n plnnetnry liocly. In s1ii.h Cases. the oil can he sucked off by means of a pipet, 9.5 i- shon-n in figure 1. 1
The botly will become spherical it' t h e specific gravity of rhe solution is not r i u c h differe n t from that of the salic!. This can be attained 113- adding, say, zinc clilori to the
solution.
This experinien: ha‘ been carried out & J x i t h :i variety of light oils and particularly n-ith gawline used for driving motor+.
FIG.1 The author had difficulty in explaining t h e ulwr\-ed phenomenon. He therefore approached Profesqor -\. Eingtein. n.li(i wa. kind enough to explain that no special hypothesis is needed, Iwcatiqe the hole phenomenon can be attributed t o currents created within tlic liquid.
H. FURUIiATT.41
ASD
G . BROOKS KING
Department of C h e m i s t r y , State College o j l V n s h i i ~ y t o n ,Pullman, Washingion Received March 18, 1944
teiiix of the type selenate-selenic acidContinuing the study of ternary water (31, the authors ha\-e tleterm t h e d u h i l i t y relations in the system magnesium selenate-selenic acid-n-ntw a t 3O’C’. Yeveral hydrates of magne.siuni selennte h a r e been reported (61. 1)lit :i> fnr 3s tke authors are an-are, no solubility determiiialioiis of iiingncsiuiii -c.kmnt t in selenic acid solutions h a w been made and no acid selenates of m:ignt-.siiun hive lieen reported. 1 Thi. paper is nn 21 ., the reci ,irenients f o r the degree oi >laster u
an-n in partial fulfillment of te College of TTashington.
