This microscope, which is not in my collection, and dates to the 1790's, was a folding alternative to the cylindrical versions Withering had devised earlier. There are at least four forms known. I am grateful to Dr Joe Zeligs for supplying me this image and also much information on the Withering folding microscopes. It features a clever arrangement which automatically erects it for use when the case is opened. The flat box is more convenient to store in the pocket than the cylindrical ones he had devised earlier.