Simple Developer. Take 1 ounce of crystalline carbonate of soda, and 2 ounces of sulphite of soda, and dissolve in 64 ounces of water; this stock solution keeps well.

To develop, take enough of the above to cover the plates, and add about two grains of pyro to the ounce; lay the plate, film side up, in the tray, holding the same in your hand, pour on the developer, and gently rock it until the details are well out in the shadows, and the high - lights strong enough. Wash the negative well under the faucet, and lay it in the fixing solution of hyposulphite of soda, and alum enough to prevent frilling. I dissolve the hyposulphite in a bottle by itself, and then add a sufficient quantity of the alum solution. In this way we have the negative developed and fixed almost as quick as by the wet process. - Thomas Pray, Jr.

If you will once try the following formulae for a concentrated developer by Mr. G. Cramer, you will like it:

Sulphite of Soda......

90 grammes.

Bromide of Ammonium ..................

15 "

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

45 "

Pyrogallic Acid......

60 "

Distilled Water......

960 "

When the solution is completed, add:

Sulphuric Acid,..................

120 drops.

Liquor Ammonia (strong).......

90 c.c.

Water in sufficient quantity to bring up the whole to the volume of..........

1200 c.c.

For use, take one part of this solution diluted with eleven parts of water. Usual Pyro Developer:

No.1- Strong Liquor Ammonia..................

1 3/4 ounces.

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

240 grains.

Water.......

80 ounces

No. 2. - Pyrogallic Acid.....

30 grains

Water,

10 ounces.

In case of an ordinary exposure, mix equal volumes.

Pyro Developer. - Pyro Solution.

Warm Distilled Water.....

2 ounces

Sulphite of Soda (C. P.)...................

2 "

Dissolve; and when cold, add -

Sulphurous Acid,....................

2 ounces

Pyrogallic Acid,....................

1/2 ounce.

Potash Solution.

A. Water,....................

4 ounces

Carbonate of Potash(C.P)....................

3 "

B.Water....................

3 "

Sulphite of Soda (C. P.)....................

2 "

of their various advocates, and to suit the different brands of plates. Each box of plates is accompanied by the formula of the manufacturer, and it is the fairest way to follow the same. Some modifications have

A and B are now combined into one solution, which will measure between eight and nine fluidounces. To develop an 81/2 x 61/2 plate which has had a drop-shutter exposure, take water 3 ounces, and add thereto half an ounce of No. 1 and 3 drachms of No. 2 of the potash solution, increasing the latter to 5 drachms in case the image hangs back. For a plate which has had the proper exposure, or which has been somewhat overexposed, add to the 3 ounces of water 3 drachms of No. 1 and 1 drachm of No. 2. After a minute's time, if the image fails to appear, add a second drachm of the potash, repeating the additions at intervals of a minute until developing commences. - F. C. Beach.

Oxalate Developer. No. 1. - Saturated solution of neutral oxalate of potash. To 1000 parts of this add 3 parts saturated solution of bromide of ammonium.

No. 2. - Saturated solution of sulphate of iron. To 1000 parts of this add 2 parts saturated solution of tartaric acid.

For use, take 4 parts of No. 1 to 1 part of No. 2. If the picture is underexposed, add a little more of No. 2.

The Old Sulphite Developer. -

No.1. - Sulphite of Soda,..................

4 ounces.

Waer,.................

40 "

Dissolve; then add sufficient of a saturated solution of citric acid to produce a slight acid reaction upon litmus - paper; now add one ounce of pyrogallic, and make up bulk to 54 ounces with water. This gives a solution, each ounce of which will contain about eight grains of pyrogallic.

No.2. - Ammonia,.............

1 ounce.

Potassium Bromide.............

180 grains

Watrer,.............

40 ounces.

Equal parts of this will give a four-grain pyrogallic solution, a strength which is a good average.

The Sulphite Developer.

No.1 - Potassium carbonate.............

45 parts.

Sodium Sulphite.............

12 "

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

1000 "

No.2 Pyrogallic Acid,.............

12 "

Sodium Sulphite.............

24 "

Cotric Acid,.............

2 "

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

1000 Parts.

For a normal development, equal proportions of No. 1 and No. 2 are used. - L. Warnerke. Soda Developer, with addition of Ammonia. - Prepared as follows:

A. - Distlled Water,.............

1500 cub. cents.

Neutral Sulphite of Soda,.............

100 grammes.

Pyrogallic Acid,.............

15 grammes.

B. - Distilled Water.............

500 grammes

Pare Crystallised Carbonate of Soda ......

50 grammes

Strong Ammonia Solution.............

2 1/2 cub.cents.

Appendix.

Ml been made since Lesson U was printed and selections from Germany,

France, England, and America follow, in order that there may be a variety to choose from.