Investigation of Flow in Liquids by Use of Birefringent Colloidal Solutions of Vanadium Pentoxide

Abstract

Abstract The author, engaged on hydrological research on the Bosphorus (1) and interested in diffusion and turbulence as biological environmental factors, was first induced to try a flow-birefringence method on a macroscopic scale, as a result of reading a paper on the shape of protein molecules (2). The use of vanadium-pentoxide sols as a birefringent medium for the demonstration of fluid flow was so successful that Prof. J. C. Bliss, Dean of the Engineering School at Robert College, encouraged the author to write a preliminary publication emphasizing the possibility of engineering application. On account of the pressure of other work, the manuscript was not ready until the beginning of September, 1945. It appears that, unknown to the author, the method of flow birefringence has been in use for some time. In a recent article by Walter Leaf (3) the following statement is made: “This process was developed in the chemical-engineering department of the Massachusetts Institute of Technology by D. R. Dewey, 2nd, under the direction of Dr. E. A. Hauser about 4 years ago.” The process involves the use of the birefringent properties of bentonite clays (named from Fort Benton, Wyoming). Jerome Alexander (4), writing in 1925, quotes a report of Edgar T. Wherry to the effect that “under the microscope, between crossed nicols, the grains (of bentonite) show distinct double refraction.…. the grains being of visible dimensions in two dimensions,…. yet of colloidal dimensions in the third.” The isolation of Istanbul during the war period perhaps accounts for the fact that the M.I.T. work was overlooked. On account of this, the title and a number of sections in the original manuscript of this paper have been modified or omitted, because their inclusion after the appearance of Leaf’s publication would have been redundant. More particularly, sections on the use of polarized light, see Taylor (5), and on the construction of experimental apparatus have either been omitted entirely or reduced to a minimum. However, it seemed in place to leave a little of the theory upon which the method is based, and to emphasize the suitability of vanadium-pentoxide sols as a birefringent medium, particularly where photographic recording is desirable.