SCIENCE AND ART.

Press, Volume LXIX, Issue 20907, 14 July 1933, Page 12

SCIENCE AND ART.

DETECTION OF FRAUDS | MADE POSSIBLE. I LECTURE BY PROFESSOR SHELLEY. "Art is an expression of feeling, while science is largely a representation of facts,'' said Professor Shelley during his address to members of the Scientific Society at ! Canterbury College last evening. | "Modern science has effected notI able improvements in the colours j used by painters, and exhaustive I tests of all types of colouring matj ters enable the present-day artist to choose those pigments which will be least affected by continued exposure to the atmosphere." Nevertheless, there were still some provinces in the field of colours which the scientist had so far failed to explore, said Professor Shelley. The most perfect blue pigment obtainable was one used originally by the Eabylonians. This true ultra-marine was prepared by powdering up the semi-precious stone, lapis lazuli, and mixing it with some suitable medium. The pigment was literally worth its weight in gold, but despite this added incentive to research, no suitable substitute had been found. The gold leaf used in illustrated manuscripts was still beaten out by hand just as it had been a thousand years ago, and the raising material used as the basis of the letters was still made from the homely recipe of .sugar, treacle, and white lead, plus a little colouring matter. The laws of perspective, established by the Italians in the fifteenth century, were the first contribution of physics to art; and modern studies on the refraction and reflection of light were also of great value.

Value of Science. "Science, however, is of most help when art becomes a matter of commerce," said Professor Shelley. "When the authenticity of a picture is questioned the details of the brush work can be examined by a microscope, colouring matters analysed by ultra-violet light, and retouching or overpainting detected by X-ray. In many cases, lost colour can be regained by chemical treatment. The white pigment used by Turner, for instance, gradually darkened, and expert treatment with hydrogen peroxide has brought back the original white."

These various methods of treatment were so important to the present-day art world that all large libraries and museums possessed a staff of experts trained for this particular work. The whole collection of pictures in the Louvre was at present being subjected to scientific tests to ensure that no copies escaped notice. A particular example of interest in that direction was the world-famous "Mona Lisa," stolen from the Louvre and later returned anonymously. Many critics declared that the picture returned was only a copy; but modern methods had proved that the "Mona Lisa" at present in the Louvre is the original picture.

Aerial Survey Work

The application of aerial surveys to archaeological studies was a comparatively unknown development of modern science. Air photographs of vast but seemingly irregular mounds revealed the remains of buried forts and cities. It was also known that crops, such as corn, growing on top of buried masonry ripened to a lighter colour than crops growing on ordinary soil, and this effect was readily observed from the air. In one part of England a buried Roman city was discovered and planned out from aerial photographs before any excavations had taken place. Professor Shelley showed several lantern slides to illustrate various phases of science that had achieved importance in the world of art.