PAPIER-MACHE.
Papier-Mache.—Pulped paper moulded into forms. It possesses great strength and is a valuable article in the manufacturing of cases for Daguerreotypes. It may be rendered partially water-proof by the addition of sulphate of iron, quicklime, and glue, or white of eggs, to the pulp; and incumbustible by the addition of borax and phosphate of soda. The papier-mache Daguerreotype cases, tea-trays, waiters, snuff-boxes, &c., are prepared by pasting or glueing sheets of paper together, and submitting them to powerful pressure, by which the composition acquires the hardness of a board when dry. Such articles are often inlaid with mother of pearl, and japanned, and are then perfectly water-proof.
CHLORIDE OF CALCIUM.
Chloride of Calcium.—This is so easily manufactured that any Daguerreotypist can make it with but little difficulty. Saturate dilated muriatic acid, say three pints of water to one of acid; this should be filtered through a sponge and then allowed to stand until all the aquus solution has evaporated and the calcium crystallized. This may be improved by it being placed in a crucible; and fused with a quick fire, then poured out on a flat stone. When cold, it should be broken and put in close bottles. This is much used by Daguerreotypists as it possesses a strong affinity for water; consequently, it is a valuable auxiliary in keeping the iodine dry. It is also much used for drying gases and absorbing water from ethereal and oily liquids, in organic analyses.
MURIATE OF AMMONIA.
Muriate of Ammonia—sal-ammoniac.—This is used by few to bleach Daguerreotype impressions, and relieve them of the "blues;" should, however, the plates be well cleaned and the mercury at a proper temperature, there will be no need of this preparation: yet, as a number have requested, we give the following combination, knowing that all Daguerreotypists are troubled more or less with solarized impressions, they may be more particularly with the blues. Make a saturated solution of muriate of ammonia, in pure water, and filter through paper. This reduced with an equal quantity of water before used; when the linen or any portion of the impression is badly solarized, after removing the coating with the hyposulphite solution, thoroughly rinse the plate with water, then pour the bleaching solution over the surface of the impression in the same manner as in gilding.
If the solarization be very deep, apply the lamp beneath and slightly warm the plate, pour suddenly off, and without rinsing, quickly apply the gilding and gild in the usual way. The whole operation must be quickly performed, or the chlorine soon attracts the shade of the picture. There may be instances when this solution may prove of advantage, as, for instance, when black velvet and milk white are wanted in the same impression. We have seen it operate with pleasing success; but repeat that few only use it, yet as in a single instance it might be of value, we have given it. As much of the muriate of ammonia, in common, is adulterated, we will give a few tests which all can try.