. The silver sunbeam : a practical and theoretical text-book on sun drawing and photographic printing. he absence of hypo-sulphite of soda, has been proposed and is practiced by J. Newton, of New York. After entirely changing thewater a number of times, he soaks the prints for a short timein a very weak solution (a half grain to an ounce of water)of acetate or nitrate of lead. The affinity of sulphur for lead forms sulphite oflead, which is insolu-ble, and the acetic ornitric acid combineswith the soda, form-ing a soluble salt,which can easily beremoved by a littlesubsequent
. The silver sunbeam : a practical and theoretical text-book on sun drawing and photographic printing. he absence of hypo-sulphite of soda, has been proposed and is practiced by J. Newton, of New York. After entirely changing thewater a number of times, he soaks the prints for a short timein a very weak solution (a half grain to an ounce of water)of acetate or nitrate of lead. The affinity of sulphur for lead forms sulphite oflead, which is insolu-ble, and the acetic ornitric acid combineswith the soda, form-ing a soluble salt,which can easily beremoved by a littlesubsequent should be takento get clear, trans-parent acetate of lead. Dr. Vogel recommends the use of asolution of iodine to remove the last traces of hyposulphitefrom the washing water. It is to be added and diffusedthrough the water so long as by combining with the hypo-sulphite its color is destroyed. As soon as the water ceasesto discharge the color of the iodine, the hyposulphite is elim-inated. We are not aware that Dr. VogeFs plan is practiced,but that of Mr. Newton is in actual and satisfactory
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