6. A quantity of ordinary starch is dissolved in hot water, and while still hot oil or wax is added, the mixture is stirred and allowed to cool. When cold a small quantity of iodine is added to give a bluish-black colour. To a gallon of this are added 8 oz. of a solution of perchloride or other per aalt of iron, and a amall quantity of gallic or tannic acid (or both), and sometimes about 2 drachms of oil of cloves with 8 oz. glycerine. The whole is thoroughly stirred.
Paste bla,eldngs are also made in a variety of ways, of which the following are the chief Bryant and James's indiarubbor blacking may be made in a solid form hy reducing the pro portion of vinegar from 20 gallons to 12. The compound then only requires stirring for about six or seven days in order t,o prepare it for use, and it may be liquefied by subsequent addition of vinegar.
2. Dr. Artna manufacturea blacking from the following materials :—Lamp-black, 3 or 4 lb.; animal charcoal, lb. ; are well mixed with glycerine and treacle, 5 lb. Meanwhile guttapercha, 2i oz., is cautiously fused in an iron or e,opper saucepan, and to it is added olive oil, 10 oz., with continual stirring, and afterwards stearine, 1 oz. The warm maas is added to the former mixture, and then a solution of gum senegal, 5 oz., in water, lb., and 1 drachm each of oil of rosemary and lavender may be added. For use it ia diluted with three or four parts of water, and tends to keep the leather soft, and render it more durable.
3. All ordinary paste blackinga require to be mixed with some liquid before application, causing considerable waste. It is claimed for the subjoined method of preparation, that by its means the blacking is rendered of such a condition that when merely dipped in water or other solvents the required quantity can be rubbed on to the article to be blacked without the cake crumbling or breaking up. The ingredients of the blacking are those in ordinary use, but it is brought to the required consistence by combinatb on with Russian tallow, in the proportion of 3 per cent., and casting the mass into the desired forma. These may be cylindrical, &c., and may be enclosed in covers of cardboard, tinfoil, &c., in which the blacking can slide, so that when one end is pushed out for use, the remainder acts aa a handle. The exposed end, when damped by immersion or otherwise, can be rubbed on the article without crumbling.
The ivory-black (animal charcoal) which has been used in the preparation of white paraffin, according to Letchford and Nation's patent, may be conveniently used for making blacking.
4. The addition of sulphuric acid to animal charcoal and sugar produces sulphate of lime and a soluble acid phosphate of lime, which make a tenacious paste. Thua : Animal charcoal, 8 parts; molasses, 4 parts ; hydrochloric acid, 1 part; sulphuric acid, 2 parts. These are well mixed. A liquid blacking may be produced from this by the addition of the necessary proportion of water.
5. Fuller's earth, 8 oz. ; treacle, 3 lb.; animal charcoal, 2 lb. ; butter scrapings, 4 oz. ; rape seed oil, 4 oz.; atrong gum water, pint ; powdered Prussian blue, oz.; commercial sulphuric acid, 8 oz. If the blacking is required in a liquid form, add gallon of vinegar.
6. To animal charcoal, 1 lb., add commercial sulphuric acid, 4 oz.; work them well together, and when the acid has done its duty upon the charcoal add fish or colza oil, 4 oz.'; stir the mixture till the oil is thoroughly incorporated, then pour in gradually a atrong solution of washing soda or other suitable antacid, and continue the stirring till ebullition ceaaes, or the acid is neutralized. Next add about 8 oz. treacle, and then pour in a solution of gelatine and glycerine, in quantity about 2 quarts if liquid blacking -is required, but less will suffice to produe,e paste. The solution of glycerine and gelatine ia made by dissolving the beat siz.e in hot water, in the proportion of 4 parts of water to 1 of size, and then adding to every quart of the liquid oz. of glycerine. The addition of the glycerine and gelatine preparation gives great brilliancy, depth of colour, and permanency to the blacking when applied to leather, and at the same time makes it damp-proof ; besides which the antacid has the effect of neutralizing the sulphuric acid employed, and thus prevents the injurious a,ction of that acid on the leather, as in the case of most ordinary blackings.
For application to dress boots the following composition is prepared :—Gum arable, 8 DZ. ; molasses, 2 oz.; ink, pint ; vinegar, 2 oz.; spirit of wine, 2 oz. Dissolve the gum and molasses in the ink and vinegar, strain, and then add the spirit of wine.