CF: G L'E TURNER THE GREAT AGE OF THE MICROSCOPE, LONDON 1989. TURNER ILLUSTRATES PP 249-256 SCREW-BARREL MICROSCOPES BY MAKERS INCLUDING JAMES WILSON, EDMUND CULPEPER, GEORGE STERROP AND ANOTHER UNSIGNED. ALL ARE SIMILAR IN CONSTRUCTION, BUT THE UNSIGNED EXAMPLE ILLUSTRATED P 256 SHOWS REMARKABLE SIMILARITY TO THE EXAMPLE ABOVE, BUT THE CASE AND ACCESSORIES ARE DIFFERENT.