Page:The chemical history of a candle.djvu/226

224 ($3$) Page 19. A little borax or phosphorus salt is sometimes added, in order to make the ash fusible.

($4$) Page 27. Capillary attraction or repulsion is the cause which determines the ascent or descent of a fluid in a capillary tube. If a piece of thermometer tubing, open at each end, be plunged into water, the latter will instantly rise in the tube considerably above its external level. If, on the other hand, the tube be plunged into mercury, a repulsion instead of attraction will be exhibited, and the level of the mercury will be lower in the tube than it is outside.

($5$) Page 29. The late Duke of Sussex was, we believe, the first to shew that a prawn might be washed upon this principle. If the tail, after pulling off the fan part, be placed in a tumbler of water, and the head be allowed to hang over the outside, the water will be sucked up the tail by capillary attraction, and will continue to run out through the head until the water in the glass has sunk so low that the tail ceases to dip into it.

($6$) Page 37. The alcohol had chloride of copper dissolved in it: this produces a beautiful green flame.

($7$) Page 54. Lycopodium is a yellowish powder found in the fruit of the club moss (Lycopodium clavatum). It is used in fireworks.

($8$) Page 58. Bunsen has calculated that the temperature of the oxyhydrogen blowpipe is 8061° Centigrade. Hydrogen burning in air has a temperature of 3259° C, and coal-gas in air, 2350° C.

($9$) Page 60. The following is the action of the sulphuric acid in inflaming the mixture of sulphuret of