312. _To make Gutta Percha Soles._--The gutta percha possesses properties which render it invaluable for winter shoes. _It is, compared with leather, a slow conductor of heat_; the effect of this is, that the warmth of the feet is retained, however cold the surface may be on which the person stands, and that clammy dampness, so objectionable in the wear of India rubber shoes, is entirely prevented. On first using gutta percha shoes, the wearer is forcibly struck with the superior warmth and comfort which is produced by this non-conducting property; and I confidently predict, that all those who try gutta percha, will be steady consumers. We shall now give the method of fixing the gutta percha soles. Make the sole of the boot perfectly clean and dry, scratch it with an awl or a fork until it becomes rough, warm it before the fire, and spread over it with a hot iron or poker some of the "solution" sold for this purpose, or in the absence of this, place some of the thin parings of the gutta percha on the sole, holding it to the fire, and spreading it as before. When this has been repeated two or three times, and all is well covered, warm the gutta percha sole, and the sole of the boot at the same time, until both become soft and sticky, place the sole on the boot, and press it down carefully, beginning at the toe, so as to press out the air and make it adhere closely; nothing more remains to be done, than as soon as it becomes hard to pare the edges with a sharp knife, and trim off as may be necessary. All the parings and old pieces should be saved, as gutta percha is not injured by use, and may be sold to the manufacturer in order to be restored and made up again. 313. _Fly Water._--Most of the fly-waters, and other preparations commonly sold for the destruction of flies, are variously disguised poisons, dangerous and even fatal to the human species: such as solutions of mercury, arsenic, &c., mixed with honey or syrup. The following preparation, however, without endangering the lives of children, or other incautious persons, is not less fatal to flies than even a solution of arsenic. Dissolve two drachms of the extract of quassia in half a pint of boiling water; and adding a little sugar or syrup, pour the mixture on plates. To this enticing food the flies are extremely partial, and it never fails to destroy them. A strong infusion of green tea, sweetened, is as effectual in poisoning flies, as the solution of arsenic generally sold for that purpose. 314. _To destroy Flies._--Ground black pepper and moist sugar, intimately mixed in equal quantities, and diluted with milk, placed in saucers, adding fresh milk, and stirring the mixture as often as necessary, succeeds admirably in occasioning their death.