BORAX BEADS-PREPARATION
OF AN EXHIBIT
C. JOHN H. BIRCH and ROBERT G. BAKER
Bishop Wordsworth's School, Salisbury, England
INTHE early stages of qualitative analysis most students would welcome an exhibit of the borax beads they may expect to obtain. The chief difficulty in preparing such an exhibit lies in the instability of some of the reduced colors when allowed to cool in the atmosphere. The use of the apparatus described below produces a well-shaped bead, cooled in an inert atmosphere, and sealed into a tube in the same atmosphere. A 500-ml. distilling flask is fitted with an inlet tube and funnel, and a piece of glass tubing is attached with rubber tubing to the side arm of the flask, as shown in the figure. An inert gas (the authors used carbon dioxide satisfactorily) is passed into the flask by the delivery tube, and the end of the glass tubing is sealed when the gas emerges from it. The gas then passes out at the funnel and keeps the whole of the apparatus filled. A borax bead is formed in the usual way on a platinum wire. On removal from the flame, the wire is tapped sharply on the edge of the funnel, and the molten bead, falling into the flask, is shaped by rolling round the bottom of the flask. The bead is then transferred, by tipping the apparatus, to the sealed tube, and the remaining end of the tube is sealed off.
