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Updated: May 4, 2025
A few days later, however, Morrow received instructions from Blaine himself, which forced his hand. The time had come for him to use the skeleton-key which he had had made. He must proceed that night to investigate the little shop of the map-maker and look there for the evidence which would incriminate him the photographic and electrotyping apparatus.
To make Plates for the Daguerreotype Determining the Time of Exposure in the Camera Instantaneous Process for Producing Daguerreotype Galvanizing the Daguerreotype Plate Silvering Solution Daguerreotype without Mercury Management of Chemicals Hints and Cautions Electrotyping Crayon Daguerreotypes Illuminated Daguerreotypes Natural Colors in Heliography Multiplying Daguerreotypes on one Plate Deposit in Gilding Practical Hints on the Daguerreotype.
For some time it was a question among the operators generally, as to the beneficial result of electrotyping, the Daguerreotype plate, but for a few years past our first operators have found it a fact, that a well electro-silvered surface is the best for producing a portrait by the Daguerreotype.
Even non-metallic surfaces could be reproduced in copper by taking a cast of them in wax and lining the mould with fine plumbago, which, being a conductor, served as a cathode to receive the layer of metal. It is by the process of electrotyping or galvano- plastics that the copper faces for printing woodcuts are prepared, and copies made of seals or medals.
Thus Hadley and Godfrey almost simultaneously invented the quadrant, the one in London, the other in Philadelphia; and the process of electrotyping was invented at the same time by Mr. Spencer, a working chemist at Liverpool, and by Professor Jacobi at St. Petersburg.
The process of electrotyping is as follows: The form is locked up very tightly, and is then coated with a surface of graphite, commonly known as blacklead, but it is a misnomer. This is put on with a brush, and may be done very evenly and speedily by a machine in which the brush is reciprocated over the type by hand-wheel, crank, and pitman.
Fossils are indices of geological formations, and must be grouped by formations to subserve the purpose of geologists. Fossils also have their biologic relations, and should be studied and arranged in biologic groups. Under the plan adopted by the Survey, the illustrations can be used over and over again for such purposes when needed, as reproduction can be made at the small cost of electrotyping.
This machine differs widely from all others in that it is adapted to produce the type-faces for each line properly justified on the edge of a solid slug or linotype. These slugs, automatically produced and assembled by the machine, are used in the same manner as other type-forms, whether for direct printing or for electrotyping, and are remelted after use.
The above quantity of this solution will be found sufficient for electrotyping a dozen of the sixth-size plates. When it is required to be strengthened, it is only necessary to add a little of the sulphate of copper.
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