The salts should be in a crystallized state, with as much water in them as possible without being damp. They should be coarsely pulverized at the time of using, and put into the water contained in a basin or other suitable vessel. The water to be frozen should be enclosed in a thin metallic vessel, and immersed in the freezing mixture. To obtain extreme degrees of cold, the ingredient* and vessels employed, should be previously cooled by one of the freezing mixtures.

1. Sal ammoniac 5 oz., nitre 5 oz., water 16 oz.

2. Mix 4 oz. of nitrate of ammonia, 4 of crystallized carbonate of soda, and 4 of water. In 3 hours 10 oz. of water may be frozen.

3. Nitrate of ammonia and chloride of ammonium in equal proportions, water q. s.

4. Nitrate of ammonia 5 parts, nitrate of potash 5, sulphate of soda 8, water 16 parts.

5. Phosphate of soda 9 parts, dilute nitric acid 4 parts.

6. Sulphate of soda 8 parts, hydrochloric acid 5 parts.

7. Sulphate of soda 6 parts, nitrate of ammonia 5 parts, diluted nitric acid 4 parts.

8. Mix 1 part by weight of powdered sal ammoniac with 2 of powdered nitre. Reduce common washing soda to powder. Keep these powders in well-closed bottles, and when required for use take equal measures of each, and add an equal bulk of water, or sufficient to dissolve the salts.

9. Chloride of ammonium 11 drs., nitre 10 drs., sulphate of soda 2 oz. Powder separately, and mix in a tin vessel with 5 oz. of water, With Ice.

1. Snow or pounded ice 2 parts, chloride of sodium 1 part.

2. Snow 2 parts, crystallized chloride of calcium 3 parts.

3. Snow 8 parts, hydrochloric acid 5 parts.

4. Snow or pounded ice 12 parts, chloride of sodium 5 parts, nitrate of ammonia 5.

5. Snow 7 parts, diluted nitric acid 4 parts.

6. Snow 3 parts, diluted sulphuric acid 2 parts. French Polish. This is an alcoholic solution of shell-lac; some of the softer resinous gums are usually added, but too much of them renders the polish less durable. Highly rectified spirit, not less than 60 over proof, should be used. Rectified wood naptha is sometimes substituted, to which the unpleasant smell is the only objection. Methylated spirit is now almost invariably employed for the manufacture of French polish, and it is advised to substitute it for the rectified spirit in the following formulae.

1. Orange shell-lac 22 oz., rectified spirits 4 pints; dissolve.

2. Shell-lac 3 oz., gum sandarac 1/2 oz., rectified spirit a pint.

3. Shell-lac 4 oz., gum thus 1/2 oz., rectified spirit a pint; dissolve, and add almond or poppy oil 2 oz.

4. Shell-lac 5 oz., seed-lac 1 oz., gum juniper 1/2 oz., mastic 1 oz., rectified spirit a pint.

5. Shell-lac 3 oz., seed-lac 3 oz., gum juniper 1 1/2 oz., mastic 1 oz., rectified spirit a quart.

6. Shell-lac 5 oz., oxalic acid 1/2 oz., rectified spirit a pint; dissolve, and add linseed oil 4 oz.

7. Shell-lac 5 oz., gum benzoin 5 oz., oxalic acid 10 drs., rectified spirit a quart; dissolve, and add 1/2 pint of linseed oil.

8. Shell-lac 8 oz., gum elemi 1 1/2 oz., rectified spirit 4 pints.

9. Shell-lac 10 oz., seed-lac 6 oz., gum thus 3 oz., sandarac 6 oz., copal varnish 6 oz., rectified naphtha 8 pints. Or dissolve 8 oz. each of seed-lac, gum thus, and sandarac, separately in a pint of naphtha; and 1 lb. of shell-lac in 8 pints of naphtha. Then mix 6 oz. of copal vaimish, 12 oz. of the solution of seed-lac, 6 oz. of the solution of frankincense, 12 of the solution of sandarac, and 5| lbs. of the solution of shell-lac. Let the copal varnish be put into the tincture of shell-lac, and well-shaken, and the other ingredients added. A correspondent informs me that this polish cannot be excelled.

10. Copal 1/4 oz., gum arabic 1/4 oz., shell-lac 1 oz. Pulverize, mix, and sift the powders, and dissolve in a pint of spirit.

11. Shell-lac 5 oz., rectified naptha a pint.

French polish is sometimes coloured with dragon's blood, turmeric root, etc. The general directions for preparing the polish are to put the gums with the spirit in a tin bottle, and set it on the hob, or in water, so as to keep it at a gentle beat, shaking it frequently. The cork should be loosened a little before shaking it, taking care that there is no flame near to kindle the vapour. When the gums are dissolved, let it settle for a few hours, and pour off the solution from the dregs. The method of using it is to have a roll of list, over the end of which five or six folds of linen rag are placed. The polish is applied to the linen with a sponge, and a little linseed oil is dropped on the centre of it.