For the second bath of cyanide of silver you may often use with ad-

Dissolve as much neutral oxalate of potassium in hot water as the water will take up (the proportion is about one to four parts), and allow it to cool. Test with blue litmus - paper; if the color of the paper remains blue, add a little of a concentrated solution of oxalic acid in water until the paper turns slightly red. Iron: Make a saturated solution of protosulphate of iron in hot water. Let it cool, and stand until settled. Decant the clear solution, and to each ounce add one drop of sulphuric acid. For the developer, mix of the two solutions enough for one day's use, in the proportion of one part iron solution to four or five parts oxalate. Add the iron to the oxalate, but never the reverse. The fresh developer is very powerful, and apt to produce flat pictures, but after being used a few times, or by getting old, will soon lose in strength, and develop slowly, with too much intensity. Therefore, the best way to proceed is as follows: Have two bottles of different shapes, but of same size, one for the new and one for the old developer, which bottles should be cleaned once every day. After developing a plate, pour the solution from the developing - dish into the bottle for old developer. Commence to develop the next plate with the old developer which you had saved, moving the dish gently, and if the picture comes out too easily, it is a sign of overexposure. In this case add a little water to it; but if after a minute the picture does not begin to appear, pour away a little of the solution, and add some from the fresh, which will bring out the picture clear and brilliant; for very short exposure, throw out the old solution entirely and finish with fresh. Wash, fix, and intensify, or reduce the same as described before. - Cramer & Norden.

Many photographers have complained, and still do so, of the fogged and flat appearance of a negative developed with ferrous oxalate, and certainly not without cause; but the vantage (though with the utmost caution, for it is just here that many a previously good result totally spoiled) a solution of ammonia:

There is still another very convenient strongthener, that of bichloride of mercury. This being composed but of a single solution, it is easier to follow its action than it is with the preceding one; but it is open to the objection of slightly fogging the plate, whilst the other makes it clearer. This strengthener is composed, as you know, of the following three solution.

If, instead of being strengthened, some of the plates should be weak ened, place them either in a weak hath of perchloride of iron, or in a highly diluted solution of cyanide of potassium; for example, one part for two hundred and titty parts of water, and stop the action of the bath at the proper time. The plate finished, strengthened, or weakened, should again be washed and allowed to remain five minutes in the following bath

This last bath possesses several advantages; in the first place, it purges the print of the injurious salts that it might contain, gives it more limremedy is in their own hands. This effect I have invariably found to be produced when the oxalate of potash has proved to be alkaline instead of neutral. To remedy this there should always be at hand a small bottle containing a saturated solution of oxalic acid, and when the required quantity of potash oxalate has been dissolved in hot water, a drop of it should be placed on a piece of red litmus - paper. If it turn the paper slightly blue, then a few drops of oxalic acid should be added, and the liquid stirred well. Test again with red litmus-paper, and if it still turn the paper slightly blue, then add a few drops more of the oxalic add solution. If found on trial again that it is neutral by its neither affecting the red nor blue litmus - paper, then the desired quantity of ferrous oxalate may be added, and the solution made up complete by the addition of a few grains of bromide of ammonium. If ferrous - oxalate developer be made from an alkaline sample of potass oxalate, the resulting negative is always foggy and weak in appearance, no matter how good the gelatin plates pidity, renders it much more solid, and makes its preservation certain. Now wash for the last time, and until the disappearance of any greasy trace, and dry without the use of heat. This drying generally requires a long time, but you can make it much shorter by dipping the plate in an alcohol bath, and allowing it to dry spontaneously, which requires about a quarter of an hour.