There were certain dangers that the builders of the Exposition had to
face. One of the most serious was that buildings erected for temporary
use only might look tawdry. It was, of course, impracticable to use
stone. The cost would have been prohibitive, and plaster might have made
the gorgeous palaces hardly more than cheap mockeries.
Under the circumstances it was felt that some new material must be
devised to meet the requirements. Already Paul E. Denneville had been
successful in working with material made in imitation of Travertine
marble, used in many of the ancient buildings of Rome, very beautiful
in texture and peculiarly suited to the kind of building that needed
color. He it was who had used the material in the Pennsylvania Station,
New York, in the upper part of the walls. After a good deal of
experimenting Denneville had found that for his purpose gypsum rock was
most serviceable. On being ground and colored it could be used as a
plaster and made to seem in texture so close to Travertine marble as to
be almost indistinguishable. The results perfectly justified his faith.
As the palaces rose from the ground, making a magnificent walled city,
they looked solid and they looked old and they had distinct character.
Moreover, through having the color in the texture, they would not show
broken and ragged surfaces.