126. Too much ears cannot be given to the selection of glass for photographic me. It should be flat, clean, and free from scratches, hubbles, and rust Fortunately, it is not difficult to find such in the market; so that about the only room there is for care, is in seeing that the plates are perfectly dean before they are coated with collodion or immersed in the bath. There are various ways of securing this - one being by the exercise of manual labor, and the other by the employment of a preliminary coating of albumen.

127. The use of the albumen substratum is now the most general. It

126. For cleaning glass and bottles, the best I have ever found is, viz.:

Saturated Solution of Bichromate of Potash, ..............................

2 ounces.

Hydrochloric Acid.......................................................................

1 ounce.

Water.....................................................................................................

5 ounces.

Let the glass or bottles remain in this twenty - four hours, or until clean; wash well, and I guarantee you will have clean glass; even old varnished negatives, or anything, it will clean them. - W.B.Critchfield.

The task of bringing glass plates to a condition of perfect cleanness is a well-recognized nuisance in photography, and anything which alleviates it will doubtless be received with satisfaction. None of the methods now in use seem to give satisfactory results without much trouble. It is otherwise with that which I am about to describe, and I think I may say that no one who tries it will ever employ any other. A convenient and large porcelain tray is to be appropriated to this purpose. In it is placed the following solution:

Sulphuric Acid............................................................................................

1 ounce.

Bichromate of Potash....................................................................................

1ounce

Water............

1 pint.

preparing a sufficient quantity to cover as many glasses as are to be cleaned. Glasses left in this solution over night (expect in very obstinate cases, which may require a little longer treatment) will generally be found to require only rinsing off, or at most a gentle rubbing, to be perfectly clean. Grease - spots, obstinate stains, remains of old collodion, and all the other troubles, lose their hold, and the task of cleaning loses, almost all its trouble. - M.Carey Lea.

127. To bring the albumen into a suitable condition,and preserve it ready for use,is the problem to be solved. This is accomplished in the simplest manner possible: Take a wide-mouth bottle of the capacity, say, of sixteen fluid ounces (provided with a well-fitting cork), is the easiest and the surest. It is less liable to cause failure, provided fresh eggs be used and the directions given are followed. Previous to any other treatment, the plates should be roughened on the edges and corners by means of a file or by emery-paper, or by drawing the edges of the plates together. This saves the fingers from injury. Now im-merse the plates in a pan of strong concentrated-lye solution, or commercial nitric arid, a couple of hours - he former if the plates are old, the latter if new - then well wash them and, while wet, flow the most concave surface with the albumen solution.

128. We are ready now to proceed with the manipulations, and, as we make the trial, let us ever remember that care, coolness, cleanliness, thought-fulness, and a sincere desire to secure good results are of absolute importance. If one does not want to do a thing well, one is apt to have sorry success. Photography needs all the desire and heart you can put into it, for chemicals are obstreperous, the elements are fickle, and constant changes need that you should always be on the alert.

and into it pour the whites of a dozen fresh eggs. Take a lump of camphor gum of the size of a hickory-nut, and inclose it in a bag of thin muslin, formed by puckering the muslin together over the camphor. Tie the bag around the neck with twine, which pass through a hole (previously perforated through the centre of the cork) from the under side; draw up closely, and fasten in place by a knot above. If the albumen is to be used for the substratum of negatives, I add one or two drachms of strong ammonia. Cork the bottle, and let stand about a week, when the albumen will be ready to be used from as required. Dilute as usual. In this way a year's supply may be put up when eggs are plenty and prime. If the albumen is to be used in a preservative or organifier for dry plates, the ammonia must be omitted. - W. H. Sherman.

In the Photographic Times, September, 1875. is a receipt as follows:

Albumen.....................................

1 ounce.

Water.......................................

8 ounces.

Ammonia..........................................

1 1/2 ,,

Iodide of Potassium..............................

30 grains.

Bromide of Potassium......................

15 ,,

Shake well, then fill up stock-bottle with water, eight ounces. This is worth gold. I forget the author's name. - E. T. Whitney.

128. For negatives, the artist needs for good work glass of ordinary strength and thickness, and free from waves and blisters. Perfection of clearness is only to be obtained in the finest plate-glass, but as it costs four or five times as much as good sheet - glass, it is hut seldom used by our photographers. We know one who used it, who afterwards substituted successfully a very superior article of clear and light-colored glass, called the "Berkshire Crystal Sheet," made from the beautiful white sand of the Berkshire Hills in Massachusetts. American glass - makers have, of late years, greatly improved their quality in regard to color, clearness, good annealing, and consequent strength and toughness. - Thomas Graffield.