7 John Wesley Hyatt 7

years a number of competing plastics were introduced

under such fanciful names as Coralline, Ivoride, and

Pyralin, and celluloid became a generic term. In 1882 John

H. Stevens, a chemist at the Hyatts’ company, discovered

that amyl acetate was a suitable solvent for diluting cellu-

loid. This allowed the material to be made into clear,

flexible film, which other researchers such as Henry

Reichenbach of the Eastman Kodak Company further

processed into film for still photography and, later, motion

pictures. Despite its flammability and tendency to dis-

colour with age, celluloid was virtually unchallenged as the

medium for motion pictures until the 1930s, when it began

to be replaced by cellulose acetate “safety film.” Other

disadvantages of celluloid were its tendency to soften

under heat and its unsuitability for new, efficient fabrica-

tion processes such as injection molding. In the 1920s

and ’30s celluloid began to be replaced in most of its

applications by more versatile materials such as cellulose

acetate, Bakelite, and the new vinyl polymers.

In the 1880s the Hyatts set up a company that employed

a patented process for purifying water through the use of

coagulants and filters. John Hyatt went on to invent a

number of new or improved industrial devices, including

roller bearings, sugarcane mills, and sewing machines.

Ferdinand von Zeppelin

(b. July 8, 1838, Konstanz, Baden [now in Ger.]—d. March 8, 1917,

Charlottenburg, near Berlin)

F

erdinand Adolf August Heinrich, Graf (count) von

Zeppelin, was the first notable builder of rigid diri-

gible airships, for which his surname is still a popular

generic term.

Zeppelin received a military commission in 1858. He

made the first of several balloon ascensions at St. Paul,