86. TO PREPARE A PHIAL THAT WILL GIVE LIGHT IN THE DARK.--Fill a small phial about one third full of olive oil; add to this a piece of phosphorus equal to one tenth of the weight of the oil. Cork the phial and wrap it in paper to exclude the light, and set it, or suspend it in a warm place, but where the heat may not be equal to that of boiling water, till the phosphorus appears to be dissolved. This phial may be carried in the pocket, and whenever the cork is started in the night, the phial will evolve light enough to show the hour on a watch. 87. TO MAKE A PERSON'S FACE APPEAR LUMINOUS IN THE DARK.--Prepare some phosphorized oil, (as directed 27,) and rub it over the face. This oil, though it appears luminous in the dark has not power to burn any thing, so that it may be rubbed on the face or hands without danger; and the appearance thereby produced, is most hideously frightful. All the parts of the face that have been rubbed, appear to be covered with a luminous bluish flame, and the mouth and eyes appear as black spots.--The luminous appearance may also be repeatedly heightened, by the friction of a handkerchief, being rubbed over the luminous part. 88. TO FREEZE WATER IN WARM WEATHER.--Draw a thread through a small glass tube; close one end and then fill the tube with water. Mix together equal parts of nitrate of ammonia and water, and immerse the tube in this mixture. The water in the tube will be frozen immediately, and may be drawn out by the thread. The same effect may be produced by a mixture of one part muriate of ammonia, one part nitrate of potass, and three parts of water. For these experiments, the above mentioned salts should be fresh, dry and finely pulverized previous to mixing; the mixture should be made in a tin vessel that is coated inside with bees-wax, and has a flannel wrapper round the outside, and the tube should be immersed quickly, as soon as the ingredients are mixed. To produce a greater, or intense degree of cold, a small vessel of water is first set in one of those freezing mixtures till it becomes very cold, and then the due proportion of the salts are added to that, and the tube, &c. immersed in it. The water in the tube may also be frozen, by continually bathing the outside of it with sulphuric ether: the evaporation of the ether, carries off the caloric of fluidity, and the water congeals.