The cost of a good heliostat mounting is about the same as that of a good telescope, and with one heliostat we can do the work of at least half a dozen of the usual instruments.
A. A. COMMON, F.R.S., and A. TAYLOR, A.R.S.M.
THE Supreme Court at St. Paul, Minnesota, handed down a decision on July 1st in the case of Ida Moore, of Minneapolis, against Photographer Rugg. Rugg sold a copy of Mrs. Moore’s picture, which was put on exhibition in improper places, much to the discredit of the lady, and she brought suit for damages. The Supreme Court holds that it is a case in which there is ground for the recovery of damages; that the photographer has no right to dispose of pictures which are the sole property of the sitter. The decision is an important one. Similar cases have arisen once or twice previously in other parts of the country.
A NOVEL CARBON PROCESS.--Mr. O. Volkner publishes the following dust carbon printing process, which appears to be easy to carry out, requires no reversed negatives, and yields permanent prints. We also think it can be used in making phototypic printing blocks. Make a solution of gelatine in water 1–60, and draw sheets of good strong paper through it, and hang it up to dry. Wet it again and squeeze it down on a piece of glass. Now brush over it a solution of ten parts gelatine, ten parts gum arabic, twenty parts white sugar, eighty parts distilled water. While still quite moist put it in a dusting box (such as used for photogravure) which contains a mixture of 100 parts of white dry sugar and five parts of French lamp black. After a lapse of eight to ten minutes, withdraw it and you will find it covered with innumerable particles of dust. Paper thus prepared will keep, and has to be sensitized in a bath of fifty parts bichromate of potassium, fifty parts bichromate of ammonia, six thousand parts water and aqua ammonia, until it assumes a light yellow color, and at last, to avoid the too quick dissolution of the gum arabic, immerse in twenty parts chromic acid in 1,500 alcohol. Print by Vogel’s photometer 16° to 18°. To develop, use warm water first, and afterwards cold, leaving the print for several hours in water, to which may be added a little aqua ammonia, in case the printing was carried too far. The prints show a singular and very pleasing grain and need no transferring.--_Dr. Eder’s Jahrbuch._