Gelatin Process
the name given to the preparation of a photographic dryplate by covering with an emulsion of sensitive salts in warm gelatin, and then drying. The plates are very much more sensitive than the old-fashioned wet plates, and have therefore made possible the photographing of rapidly moving objects. The exact composition of the gelatin emulsions varies considerably, and is kept secret by the different manufacturers, but generally speaking, the chemicals used in their manufacture include silver nitrate, ammonium bromide, potassium bromide and potassium iodide.
GELNHAUSEN (geln'hou-zen), town of Prussia, on the Kinzig river, and on the slopes of a vine-clad hill, 26 miles N. E. of Frankfort-on-the- Main. Here, on an island in the Kinzig, Frederick Barbarossa built an imperial residence ("the Pfalz"); and in 1169 he conferred on the village the freedom of the empire. After being transferred to the counts of Hanau in 1435, Gelnhausen began to decay. a GELSENKIRCHEN (gel'zen-kērchen), a modern manufacturing town of Westphalia, 4 miles N. W. of Bochum.
It owes to coal and iron its rise from a mere village since 1860. Pop. about 170,000. a