R. L. Maddox, M.D.”
After perusing the above, it will be evident to any one that Dr. Maddox very nearly arrived at perfection in his early experiments. The slowness that he complains of was caused entirely by not washing the emulsion to discharge the excess of bromide, and the want of density was due to the absence of a restrainer and ammonia in the developer. He only made positive prints from negatives; but the same emulsion, had it been washed, would have made negatives in the camera in much less time. Thus, it will be seen, that Dr. Maddox, like the Rev. J. B. Reade, threw the ball, and others caught it; for the gelatine process, as given by Dr. Maddox, is only modified, not altered, by the numerous dry plate and gelatino-bromide paper manufacturers of to-day.
Meanwhile collodion held the field, and many practical men thought it would never be superseded.
In this year Sir John Herschel died at a ripe old age, seventy-nine. Photographers should revere his memory, for it was he who made photography practical by publishing his observation that hyposulphite of soda possessed the power of dissolving chloride and other salts of silver.
FOURTH PERIOD.
Dr. R. L. MADDOX.
From Photograph by J. Thomson.
GELATINO-BROMIDE EMULSION 1871.
