Читать книгу A Practical Manual of the Collodion Process. Giving in Detail a Method For Producing Positive and Negative Pictures on Glass and Paper онлайн

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Articles necessary.—One quart Wedgewood mortar and pestle, or evaporating dish; one glass rod; one pane of glass, large enough to cover the mortar or dish; one ordinary-sized pail two-thirds full of pure rain or distilled water, and at least ten times that quantity of water at hand; twelve ounces (by weight, avoirdupois) of nitrate of potash (Dupont's refined, pulverized); twelve ounces (by measure) of commercial sulphuric acid; and three hundred and forty grains of clean, pure cotton wool.

Remarks.—It is advisable that the mortar or dish be deep and narrow, as the mixture can be better formed in a vessel of this shape. If not convenient to procure a mortar, a common earthen bowl will answer; glass is objectionable, as the heat generated in the combination of the acid and nitre is liable to crack it. A new pail should not be used, especially if it is painted, as the acids attack the paint, and injure the cotton. I prefer one that has been used for some time, and has been frequently cleaned. A common earthen wash-bowl, or any large glass dish, will answer in place of the pail. Metal pails or vessels should not be used.