Twenty years ago, said Dr. Hollingsworth, it was a common practice to over expose, whereas, nowadays, with beginners, at least, it seems to be nothing but hand cameras and under exposure, and it seems unfortunate that the most difficult process of exposure should come first.

With a negative that is technically good we can do almost anything, but if we get a defective one it is only by dodging, and experience at that, we can overcome its defects. Under and over exposure teaches us that there are limitations within which exposure lies, and that it takes time for the light to impress the image upon the plate.

In taking photographs we have to deal with or consider, a number of factors. Some of these take the form of atmosphere, wind, fogs, varying conditions of lighting, the summer or winter, and the difference in the actinic value of the light brought about by the changes of the seasons, and, finally, with the important matter of the subject itself.

Then, again, many beginners do not find out for a long time the value of the stops, though this has a great deal to do with the length of the exposure and the results obtained. It should be understood that each one, as we work down, practically doubles the exposure. In focussing at open aperture (which is the correct method) it is best to aim at sharpening up any object about a third of the distance away, and then to stop only sufficient to bring the whole field of view into equal focus.

There is also the question of fast plates and slow one. The tyro generally uses the former, although the latter are the most easy to control. The fast makes are more easily damaged by fog in the dark room, owing to the unnecessary and continuous practice of frequently looking through the plate to see how development is going on.

There is a golden rule - expose for shadows, and the rest will take care of themselves, which each must always bear in mind if he wants to make the negative a successful one.

The use of an actinometer was strongly recommended, so that some guide may be followed. It will save its cost over and over during a busy season.

Metol seemed to have the faculty of bringing out detail before it piles up density. With it one has to take the plate further than seems to be necessary, as it looses a good deal of density during fixation.

It is most important, if one wants to do good work to stick to one developer and master it before one makes any change. The same rule applies equally to the plate. We should thoroughly understand one particular kind, exhaust its possibilities, instead of flirting about from one to another. If this is followed out, the more experience one gets the more will he find that one make is perhaps as good as another and capable of producing good negatives if the exposure and development are correct.

A French photographer, M. G. A. Liebert, has recently devised an apparatus which will enable him to take instantaneous photographs in his studio. This device is described in Le Revue Patrique de l'Electricite for December 5. The object of using electric lights is to give the photographer entire control of the quality and amount of illumination and to render him independent of daylight. Moreover, to obtain the best portraits it is very desirable that they should be taken instantaneously and at the moment when the subject is in the best pose.

The device consists of a large parabolic reflector of aluminum, having placed on its inner edge a series of incandescent lamps shaded with ground glass screens. The object of these is merely to light up the subject, permitting the photographer to secure the best pose and to determine when the real exposure should be made. At the center of this reflector is an arc lamp with three carbons. One of these is fixed and the other two are moveable. When a photograph is to be taken, the subject is arranged and the sensitive plate is •exposed. The photographer then waits until a desirable pose has been secured, when he presses a rubber bulb, which draws the two movable arc light carbons across the fixed one, thus forming a brilliant arc; but the moment the current passes through the lamp the movable carbons are drawn away from the fixed one by means of an electromagnet, and the arc is thus extinguished. It lasts about one-fiftieth of a second, but this gives sufficient time for an exposure.