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ssible with the spirit lamp； small bubbles will arrise； and the appearance of the portrait or view very sensibly improved。 The process must not be carried too far； but as soon as the bubbles disappear the lamp should be removed； and the plate immersed in distilled water； and dried as before directed。
7th。 COLORING THE PICTURE。I very much doubt the propriety of coloring the daguerreotypes； as I am of opinion； that they are little； if any； improved by the operation； at least as it is now generally practised。
There are several things requisite in an artist to enable him to color a head； or even a landscape effectively； and correctly； and I must say that very few of these are possessed by our operators as a class。 These requirements are； a talent for drawingtastedue discrimination of effectstrict observance of the characteristic points in the features of the subjectquick perception of the beautiful； and a knowledge of the art of mixing colors； and blending tints。
The method now pursued； I do not hesitate to say； and have no fears of being contradicted by those capable of critisizing is on the whole ruinous to any daguerreotype； and to a perfect one absolutely disgusting。 The day may come when accurate coloring may be obtained in the camera。 Until that day； if we cannot lead taste into the right channel； we will endeavor to give such instructions that Daguerreotypists may proceed with this part of his work with a better understanding of the principles involved。 For this purpose I have prepared a short chapter on the art of coloring； which may be found in the latter part of this volume。
To Preserve Daguerreotypes they must be well sealed and secured in a case； or frame。 These； of course； are selected according to the taste of the customer； the principal requisite being good glass。 Most Daguerreotypists prefer the white French plate glassand many think； very erroneously； that none is good unless it is thick but the great desideratum is clearness and freedom from blisters； even glass a little tinged with green or yellow is to be preferred to the French plate when cloudy or blistered and there is very little of it comes to this market that is not so。 It is to be hoped that some of our glass factories will manage to manufacture an article expressly for daguerreotypes； and I would recommend them to do so； for they would find it quite an item of profit annually。
Before enclosing the picture in the case you should be careful to wipe the glass perfectly clean； and blow from the picture any particles of dust which may have fallen upon it。 Then take strips of sticking paper； about half or three quarters of an inch wide； and firmly and neatly secure it to the glass； having first placed a 〃mat〃 between them to prevent the plate being scratched by the glass。
TO MAKE SEALING PAPER。Dissolve one ounce of gum arabic； and a quarter of an ounce of gum tragicanth in a pint of water； then add a teaspoonful of benzoin。 Spread this evenly on one side of good stout tissue paper； let it dry； and then cut it up in stripes； about half or three quarters of an inch wide； for use。 If it becomes too soft for summer use； add gum arabic； if too hard and cracking； add benzoin or gum tragicanth； if it gets too thick； add water。
COLORED DAGUERREOTYPES ON COPPER。To effect this； take a polished plate of copper and expose it to the vapor of iodine； or bromine； or the two substances combined； or either of them in combination with chlorine。 This gives a sensitive coating to the surface of the plate； which may then be submitted to the action of light in the camera。 After remaining a sufficient time in the camera； the plate is taken out and exposed to the vapor of sulphuretted hydrogen。 This vapor produces various colors on the plate； according to the intensity with which the light has acted on the different parts； consequently a colored photographic picture is obtained。 No further process is necessary as exposure to light does not effect the picture。
By this process we have an advantage over the silvered plate； both in economy； and in the production of the picture in colors。
INSTANTANTANEOUS PICTURES BY MEANS OF GALVANISM。It will be seen by the following valuable communication that galvanism can be successfully applied in producing pictures instantly； a process of great importance in securing the likeness of a child； or in taking views of animated nature。 Colonel Whitney informs me that he once took a view of the steeple of the St。 Louis Court House after sundown by this means） and also secured the image of a man in the act of stepping into a store； and before he had time to place his foot； raised for that purpose； on the door step。 Mr。 Whitney is well known as the talented editor of the Sunday Morning news。
New York； January 16； 1849。 Mr。 H。 H。 SNELLING。
Dear Sir；As you are about publishing a history of the Daguerreotype； and request a description of my mode of taking pictures instantaneously by the aid of galvanism； I comply with great pleasure。
In the year 1841； while practicing the art in St。 Louis； Mo。； I was at times； during the summer； much troubled with the electric influence of the atmosphere； especially on the approach of a thunder…storm。 At such times I found the coating of my plates much more sensitive than when the atmosphere was comparatively free from the electric fluid； and the effect was so irregular that no calculation could counteract the difficulty。 This satisfied me that electricity was in some measure an important agent in the chemical process； and it occurred to me that the element might be turned to advantage。 I determined； therefore； to enter on a series of experiments to test my theory。 Finding it impossible to obtain an electric machine； and unwilling to abandon the examination； it occurred to me； that the galvanic influence might answer the same purpose。 I therefore proceeded to make a galvanic battery in the following simple manner。 I obtained a piece of zinc about two inches long； one inch wide； and an eighth of an inch thick。 On this I soldered a narrow strip of copper； about six inches long； the soldered end laid on one side of the zinc； and extending its whole length。 The battery was completed by placing the zinc in a glass tumbler； two…thirds full of dilute sulphuric acid； strong enough to produce a free action of the metals。 The upper end of the copper slip extending above the tumbler was sharpened to a point； and bent a little over the glass。
The method of using； was thus：After preparing the plate in the usual manner and placing it in the camera； in such manner as to expose the back of the plate to view； the battery was prepared by placing the zinc in the acid； and as soon as the galvanic fluid began to traverse （as could be known by the effervessence of the acid； operating on the zinc and copper） the cap of the camera was removed； and the plate exposed to the sitter； at the same instant the point of the battery was brought quickly against the back of the plate； and the cap replaced instantly。 If the plate is exposed more than an instant after the contact the picture will generally be found solarized。 By this process I have taken pictures of persons in the act of walking； and in taking the pict