870. Since the publication of the preceding pages, the art of photography has made some tremendous strides. The manufacture and manipulation of bromo-gelatine-emulsion dry plates has been very much modified since the publication of Lesson U, though the results are no better. Greater speed has been attained, which is sometimes an advantage and at other times a decided disadvantage, for it has led many a novice into the blunder of " working for speed" at the sacrifice of quality in result.

While all these changes were going on, some good and faithful plodders have occupied themselves in the endeavor to supply a substitute for glass. Their efforts have been attended by great success.

Again, in printing processes many new things have been worked out which simplify the operations and increase the pleasure of the worker in photography.

870. Up to within a comparatively short period, the general belief of the photographer was that the quicker the exposure the stronger must be the developer used, and in the hands of the veteran, beautiful negatives were and are produced, because his experience taught him what to expect and how to realize his anticipations. But we fear that many a tyro amateur, with his quick shutter or detective camera, failed to have his hopes end in fruition, and saw more than the first dozen of his very rapid plates ruined - either fogged by development, or so weak and thin that all the intensifiers that he ever read about would not bring them up to the desired density or detail. It was doubtless in great measure due to these failures, and consequent heartaches, that the second part of the question, " strong or weak?" made its appearance, and many amateurs plunged boldly into a aeries of experiments to solve the vexed question (especially vexatious to many) to their own satisfaction, even if they failed to convince others. As the subject stands now, it is not settled, but each side has its own band of earnest advocates.

It is not my purpose now to treat of all of these in detail. I shall select the best - the most practical - and thus inform the reader fully how to produce all the new things in photography, by the easiest and simplest means.

Very few persons, in these days of plentiful dry-plate factories, attempt to manufacture their own plates; therefore, I shall only treat of the manipulations.

There are two grades made by each manufacturer, as a rule - those working with ordinary rapidity and those which are as " quick as lightning." For almost all kinds of subjects, in the hands of the novice, the first are preferable. For photographs of animals and moving objects, and for marine views, the " quick " plates are the best.

Mr. C. Faber says, in a communication to the Belgian Photographers' Association, that this question has often been put to him, and that for the last three years he has found nothing that can be compared to the concentrated developer of Dr. Eder:

Neutral Oxalate of Potash..............................

60 grammes.

Sulphate of Iron,..................

20 "

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

100 grammes.

Neutral oxalate of potash.is dissolved in boiling-water, and this solution is kept at a temperature between 194° F. and 203° F., while sulphate of iron is dissolved in it. It is then set aside for twenty-four hours, and the clear liquid decanted off the crystals that have formed at the bottom of the bottle, and is ready for use. He says that it is the most energetic developer for gelatino - bromide plates. In the next sentence he says: "If the action of this developer is found to be too rapid, it suffices to dilute it with more or less water. By adding an equal volume of water, we obtain a bath which acts still more rapidly than the developer made by the usual formula."

That the advocates for a weak developer are numerous, can assuredly be seen in the current photographic literature of the day, and certainly many beautiful results of their work are proudly exhibited to be admired, as they deserve to be. Quite recently, the advantage of using two solutions, instead of a combined one, has been strongly advocated by many earnest workers and experimentalists, who claim for this method a greater control of the process of development, and a certainty of results not to be obtained by any other.

A sort of cross, or half way, between the one and two solutions, has also been proposed '"hat is, by giving the plate a bath of water and then placing it in a combined solution. Mr. Eugene Albert, in a plea for over-timing, says that when he cannot over-time - or, in other words, when he makes a rapid exposure - that after letting the plate lie in plain water for ten minutes, covering it up, of course (a decidedly necessary procedure), he then washes it by pouring water over it, and then puts it into the combined developer. He further says that it is strange, but it is a fact, that the washing, after removing the plate from the plain water, facilitates the development. - Dr. John H. Janew ay.