This is a process, invented by Dr. Taupenot, for obtaining negatives on glass, which bids fair to outrival all others, being easy of manipulation, and giving results of the most exquisite minutiæ and beauty. Glass plates, when prepared and excited by this process, may be kept at least a fortnight before being developed, and these plates when exposed in the frame may be developed immediately, or kept for days before commencing this operation. Indeed it is quite possible to prepare and excite a number of plates before leaving home to go on a tour of twelve or fourteen days; to expose the plates at any time or place during the journey, and bring them home to be developed. The manipulation may be said to consist of nine distinct operations. 1. Cleaning the plate. 2. Coating with iodized collodion. 3. Exciting the collodion film. 4. Coating with albumen. 5. Exciting the albumen coating. 6. Exposure in the camera. 7. Developing the image. 8. Fixing the image. 9. Varnishing the plate. Before describing these operations, I propose to give clear directions for preparing the necessary solutions, merely promising that, where I have deviated from the inventor's plan, it has been after performing careful experiments, to test the merits of the two modes of proceeding. The necessary solutions for this process are: Collodion bath solution. Iodized collodion. Iodized albumen. Albumen bath solution. Pyrogallic solution. Silver developing solution. Fixing solution. _Collodion Bath Solution._ Nitrate of silver in crystals 1 ounce. Iodide of potassium 2 grains. Distilled water 16 ounces. Alcohol 2 drachms. Dissolve the ounce of nitrate of silver in two ounces of the distilled water, and the two grains of iodide of potassium in one drachm of distilled water; mix the two solutions and shake well together until the precipitate which is first thrown down is re-dissolved; when this takes place, add the remaining fourteen ounces of distilled water, and the two drachms of alcohol. On the addition of the water a turbidness ensues, which must be removed by the solution being very carefully filtered through filtering paper; and the filtered liquid should be clear and transparent, free from any deposit or floating particles, and must possess a slightly acid reaction of test-paper. In order to ascertain if the solution thus prepared possesses the necessary amount of free acid without superabundance, proceed to test and to correct it, if necessary. _Iodized Collodion,_