Schumann's statement that a gelatino bromide plate is less sensitive when developed at 30 deg. C. than when developed at 5 deg., is contested; the more recent investigations of Dr. Eder serving to demonstrate that a developer at a moderate high temperature acts very much more rapidly than when the temperature is low; but when a sufficient time is allowed for each developer to thoroughly penetrate the film, the difference becomes less apparent. Here are examples: _A.--Oxalate Developer._ Temperature of developer 4-8 deg. C. 16-17 deg. C. 26-28 deg. C. Time of development 1 min. 3 deg. W. 8 deg. W. 13 deg. W. " " 2 min. 91/2 deg. W. 10 deg. W. 15 deg. W. _B.--Pyrogallic Developer._ Temperature of developer 1-2 deg. C. 26-28 deg. C. Time of development 1/4 min. 6 deg. W. 10 deg. W. " " 3 min. 14 deg. W. 15 deg. W. * * * * * INTENSIFIER FOR WET PLATES. By MAJOR WATERHOUSE. The collodion process is still preferred for reproducing black and white designs, drawings, engravings, etc., where very dense negatives are desirable. The fixed and washed plate is put in a bath of bromide of copper (ten per cent. solution); the film whitens immediately, and when the color is even all over, the plate is taken out and plunged into a bath of the ordinary ferrous oxalate developer. It takes a dark olive tint, which is very non-actinic, the shadows meanwhile remaining very clear.--_Photo. News._ * * * * * GELATINO BROMIDE EMULSION WITH BROMIDE OF ZINC. By this time of the year I have no doubt many, both amateur and professional photographers, are either contemplating or are actually at work making their stock of plates for the coming season, and it is to be hoped that we shall have more favorable weather than we had last year. Some four or five years since I tried using bromide of zinc instead of the ordinary salts, namely, bromide of ammonium or potassium. I only made one batch of plates at the time, which possessed several important features I considered an advantage, and I think well worth while following out. I do not think it can be denied that ordinary gelatine plates, if exposed in a weak light, fall very short of the results obtained with wet collodion when compared side by side, gelatine being almost useless under these conditions, and there is a decided gain in the result in this respect if the emulsion be made with zinc bromide.