Consequently he first photographed the model on the level. Then he photographed the photograph tipped forward at an angle equal to overcoming the distortion in reverse. Thus a distorted slide was made to meet precisely the conditions on the mountain where the design was to be placed. As a result the picture appeared at that high elevation as it would directly in front of the lens. The picture was then traced on the mountainside in white to guide the blocking-out process of the carvers.
The lamp, weighing about a ton, was bolted to a concrete foundation to avoid the slightest movement. It would be swung to any angle, up and down, right and left. A slide three inches high produced a picture 200 feet high. The enlargement was so great that a pin scratch on the slide measured nine inches in width on the mountain. The head of Lee’s horse was thirty feet from tip of ear to end of lip; the stirrup was nine feet long. A man standing on Lee’s shoulder needed a nine-foot stepladder to carve the ear.
In these dimensions absolute precision was of the utmost importance. A telephone for communication between the operator and workers on the mountain was installed so that with micrometer adjustments, the same picture could be superimposed night after night on the incomplete tracings. In addition to locating the design on the mountain the lamp made possible infinite changes in the original plan. Even a complete change in the composition of a dozen horses or a hundred soldiers could be projected on the mountain and the effect of the change shown at once.
The picture as it appeared on the mountain shown at night was as clear as the scene in a movie. In fact, one night when the photograph was being shown a passer-by stopped in great excitement, thinking that the figures had already been carved, so lifelike was the illusion. The projection machine, Gutzon estimated, saved him at least two or three years’ labor in placing his sketch upon the mountain.
A third problem, equally important and seemingly insolvable, was what could be done to remove the stone with the rapidity and facility that a sculptor enjoys when he works on a marble bust in his studio? This thought occurred to Gutzon before he even measured the acreage he intended to use for his carving. How could he whip these enormous dimensions and reduce a mountain to a handful? He related this experience in an article later produced in the Dupont trade magazine. He said:
When I first put drill to that eight-hundred-foot-high block, directing the hands of men I could hardly see at a distance of fifteen hundred feet, I was still impressed by the thought that without some effective substitute for the thousands of enslaved craftsmen of the Egyptian days, our undertaking would never come to an end. I spent weeks experimenting with the ways and means of blocking out masses of unnecessary stone and trying by plug and feather and wedge drills to split them off. All these efforts proved childish and inadequate. After months of failures and careful calculation of costs I began to see that the work would be next to interminable with the labor we could afford and by the known means at our disposal.
I had thought of explosives but, knowing little about them, had vetoed their use. The general idea is that high explosives can be used only to destroy. As I thought this subject over, much as I am writing it, another thought came to me: Why not control explosive force? Firearms control it. Why not develop some means by which we could blow off just what material we wanted to be rid of, in precisely the quantities we wished to remove, and at the same time preserve the stone left in place, intact and without injury? That problem I pondered over for months without discussing it with anybody.
Just at that time a Belgian engineer, who was passing through Georgia, visited me at Stone Mountain. I told him what our difficulties were, quite apart from the safety problem of carrying men to such a height apparently unprotected, to work on the side of the mountain. The removal of stone was costing too much and was too slow. The old methods were detaining the development of the design.
“Why don’t you use dynamite?” he calmly asked.
“I’ve been thinking of it,” I said, “and I am on the point of making experiments. But it’s close work.”