SEPARATION OF MAGNETIC PARTICLES UNDER THE MICROSCOPE EUGENE W. BLANK Research andDevelopmentDe artment, Colgate-Palmolive-Peet Co., Jersey s t y , New Jersey
THE separation of magnetic particles from a mixture is an operation frequently attempted under the microscope. Chamot and Mason1 list several pertinent references dealing with the subject. In all cases the use of a small, permanent magnet, or an electromagnet is advocated. Their use presents the serious difficulty that though the magnetic particles are separated from the mass of material they cannot be readily isolated and recovered, due to the fact that the particles themselves become magnetized and tenaciously adhere to the magnet. The difficulty is readily eliminated by covering the magnet with glass. The protected, magnetic pole of the magnet can then be inserted directly into a drop of add and the metallic particles dissolved or the particles can be brushed loose by means of a platinum wire or washed free of attachment with a fine stream of water. The figure shows a suggested type of apparatus which can be modified to suit the experimental conditions.
The thick portion of the tube is wound with several layers of Number 30 wire and connected to a dry cell. Two fiber guards are cemented to the tube to hold the layers of wire in place. The thick portion of the tubing covered by the wire contains several iron wires to reinforce the magnetic field of the single iron wire extending to the tip of the thin section of the tube.
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CWOT,E. M. AND MASON,C. W., "Handbook of chemical miaoscapy," Vol. 1, John Wiley &Sans, Inc., New Yark City. 1930, p. 200.
