518. _To avoid Grey Hairs._--Those who would avoid that prominent mark of approaching old age, called grey hair, must be careful in the treatment of the hair in their youth. They must avoid constricting the skin, and strangling the hair at its roots, and everything that may throw into the blood an undue portion of lime. We say an _undue_ portion, because a certain quantity of lime is indispensable in our system for repairing the wear and tear of the bones, teeth, &c. The lime necessary for the repair of bone is manufactured by the stomach and liver, along with the blood, from various articles of our diet which contain it. The greatest supply is usually from the water which we drink, or which is employed in the various processes of cooking and preparing liquors. All animal food also contains some portion of lime, as well as some of the sorts of vegetable food. Ascertain, then, by chemical trial, whether the water used for your tea, coffee, soups, &c., contains a large proportion of lime; and, if it do, you must either have it chemically purified, or remove to some other place where the water is more free from lime. If water be hard, you may be certain that it contains too much lime to be safely used. Rain-water is the safest for tea and other liquids. Bread will always contain a portion of lime; you must, therefore, be careful in dealing with respectable bakers, who will not increase that unavoidable quantity by means of adulterating matter (such as whiting) which contains lime. 519. _To soften and cleanse the Hair._--Beat up an egg, rub it well into the hair, and then wash the head well. If the hair is very oily, add the juice of half a lemon. This receipt also answers much better for washing pet dogs than soap. 520. _To make a Curling Fluid for the Hair._--Melt a piece of white bees'-wax, about the size of a filbert kernel or large pea, in one ounce of olive oil; to this add one or two drops of attar of roses or any other perfume. 521. _Gen. Twiggs' Hair Dye._--Dissolve in a pint of rose-water, one ounce of lac sulphur, and half an ounce of sugar of lead. Wet the hair with this mixture thoroughly every night, shaking the bottle occasionally. Some persons prefer whisky to rose-water, in mixing the articles. 522. _To change Hair to a deep Brown._--A solution of silver caustic in water is the foundation of all the nostrums for this purpose. It must be well diluted before used. 523. _To dye the Hair Black._--Procure from the dyer's a quantity of walnut-water; and with this wash the hair, as the first part of the process. Then make an aromatic tincture of galls, by scenting the common tincture with any agreeable perfume; and with this wet the hair, which must next be moistened with a strong solution of sulphate of iron. 524. _A simple Hair-dye._--Boil in a pint of water a handful of rosemary; when cold, strain and bottle, but do not cork it. Renew it every few weeks. Wet the hair with it every night.