No.1. Pyrogallic Acid,....................

1 ounce.

Glycerin,....................

1 ounce

Methylated Alcohol,....................

6 ounces

Mix the glycerin and spirit and add to the pyro.....................

No. 2. - Bromide of Potassium (or Ammonium),. . .

60 grains.

Liquor Ammonia,880,....................

1 ounce

Glycerin,....................

1 "

Water,....................

5 ounces

The above stock solutions will keep any length of time. To make the developer, add one part of No. 1 to fifteen parts of water, and label this bottle D (developer). In another bottle mix one ounce of No. 2 with fifteen ounces of water, and label it A (accelerator). It will be found convenient, to avoid mistakes in the imperfect light of the dark-room, to have these two bottles of different shapes. Either of the above solutions will keep two or three days. When required for use, pour into a clean glass measure equal parts of D and A, adding the A last, just before using. Place the dry, exposed plate face up in a shallow dish or tray, and pour the mixture steadily over the plate, avoiding air-bubbles; should any adhere to the surface of the plate, at once remove them with the finger or a camel's-hair brush kept for the purpose. Rock the dish gently, taking care to keep the plate well covered with the solution. In a few seconds the image will appear, and, if the exposure has been well timed, all the details will be out and the development complete in about one minute, when the negative should be well washed under the tap and placed at once in the fixing - bath. Do not hurry the development, but allow the plate to remain in the solution, after all the details are visible, until the required density is obtained. "With this developer used in the above proportions there is no danger of fog, except from the action of light. If on the application of the mixed developer the image flashes out and the details in the shadows appear too quickly, it will indicate that the plate has been over - exposed; therefore at once throw off the mixed developer, and, without stopping to wash the plate, flood it with D alone, when the development will be checked, and will proceed more slowly, while the image gains in density. If too slowly, or tbq negative appears to be getting too intense, add a very little of A. There will, however, usually be sufficient of the latter left on the plate to complete the development with the simple addition of a sufficient quantity of solution D. A very little experience will enable they available. It will require the nicest and most tboughtful application and handling, bul it will reward you for you care. Mr. Carbutt has reduced its manipulation to a very fine end system by his method, given in the notes below, of mixing the ingredients as they are about to be used.

operator to produce a good printing negative from a plate which, if developed with the full proportion of A, would have been utterly useless from over - exposure. (In very warm, bright weather it will, perhaps, be found an advantage to use rather more D than A in the mixed developer, giving just sufficient exposure to avoid hardness in the negative.) Under-exposure can be corrected to a great extent by increasing the proportions of A in the mixed developer, but the addition should be made at once before the development has proceeded too far, or the effect will be to increase the density and cause too much contrast in the negative. The proportions of the mixed developer can be varied at will by the operator, according to the character of the results he wishes to produce. - B. J. Edwards.

Pyrogallic acid during the past year has obtained an evil report; and, as it is no longer looked upon as indispensable, there seems some chance of its reputation drifting from bad to worse. Now, it is conceded by nearly all experienced dry-plate workers that alkaline pyrogallic is the most elastic of our developers, and had it not lately acquired a character for producing yellow-brown negatives and stained films, would still be generally preferred. The cause of these troubles is mainly due to a forced and rapid development, produced by a strong alkaline solution, subject to rapid oxidation, and insufficiently restrained. It is a far better plan to build the image gradually, when both color and gradation will be improved to a wonderful extent. In carrying out this method, a four-grained solution of the crystallized neutral sulphite of soda will be found very useful. This is to be used for all operations up to the immersion of the plate in the alum bath before fixing. In hot weather it is valuable also as a reducer of the temperature of water. As an absorber of oxygen it prevents the oxidation of the pyre, and with the sulphate formed it is also a restrainer. The developer thus made is only slightly tinted after the development of a plate, and at the end of many minutes. The sulphite does not seem, however, to have much power in preventing "red and green fog." This effect, when it occurs, is to be found at the margins, and generally in the less exposed parts. No doubt in rocking the dish these portions of the film are more affected by the oxygen of the air, although it would seem that different samples of plates vary much in their liability to this most annoying kind of stain, which may be contracted even when this developer is only tinted by the oxidized pyrogallic. Dilute hydrochloric acid does not seem to have a very energetic action upon the stains. Perchloride of iron acts readily, but there are some objections to its use. It has also a tendency to deposit an insoluble body, in appearance like the hydrate. A very good mixture for removing the color from uniformly stained films - especially when the negative is too dense - will be found in a saturated solution of alum, to every four ounces of which one drachm of hydrochloric acid has been added. This removes the stain, changing the color of the image to a blacker tint, and, when allowed to act for several minutes, reduces the density considerably. Indeed, it might seem to be a better plan to run the risk of getting too much density during the development, than, fearing this, have to resort to intensifying after fixing. This mixture is not a new one, as at first I supposed it might be, for it had been employed to remove pyro stain by others prior to its use occurring to me. As a reducer of the intensity of pyro-de-veloped negatives, it may be new to many - Herbert B. Berkeley.