Soap Bubbles
and the Forces which Mould Them

'The forces which mould them. 137 flat above, until the sides are evenly turned down all round. This is quite easy, because the wires can allow of the kind of distortion necessary. Then wind round the turned-up edge a few turns of thick wire to make the sides stiff. This ought to be soldered in position, but pro- bably careful wiring will be good enough. Melt some paraffin wax or one or two paraffin candles of the best quality in a clean flat dish, not over the fire, which would be dangerous, but on a hot plate. When melted and clear like water, dip the sieve in, and when all is hot quickly take it out and knock it once or twice on the table to shake the paraffin out of the holes. Leave upside down until cold, and then be careful not to scratch or rub off the paraffin. This had best be done in a place where a mess is of no consequence. There is no difficulty in filling it or in setting it to float upon water. Narrow Tubes and Capillarity. Get some quill-glass tube from a chemist, that is, tube about the size of a pen. If it is more than, say, a foot long, cut off a piece by