Section 3. The test-lamp is prepared for use by fitting it with a piece of flat plaited candlewick, and filling

3. The test-lamp is prepared for use by fitting it with a piece of flat plaited candlewick, and filling it with colza or rape-oil up to the lower edge of the opening of the spout or wick-tube. The lamp is trimmed so that when lighted it gives a flame of about 0·15 of an inch diameter, and this size of flame, which is represented by the projecting white bead on the cover of the oil-cup, is readily maintained by simple manipulation from time to time with a small wire trimmer. When gas is available it may be conveniently used in place of the little oil-lamp, and for this purpose a test-flame arrangement for use with gas may be substituted for the lamp.