Jacob Metius else from claiming them. In October 1608, the States General discussed Jacob Metius's patent application for a device for "seeing faraway things as though nearby," consisting of a convex and concave lens in a tube, and the combination magnified three or four times. His use of a convex objective lens and concave eyepiece may have been a superior design to Hans Lippershey telescope design which was submitted for patent only a few weeks before Metius'. Metius informed the States General that he was familiar with the secrets of glassmaking, and that he could make an even better telescope with the
Compound refractive lens the order of meters, by using many lenses in series. To minimize the absorption the lens must be made from a material such as aluminium, beryllium, or lithium. CRLs were first demonstrated in the mid-1990s by a group of scientists at the ESRF. They drilled holes in an aluminium block, and achieved focusing in two dimensions. For X-rays a concave lens focuses the X-rays because the index of refraction is slightly below unity. In a CRL of this type the walls between the cylindrical holes act as concave lenses for X-rays traveling perpendicular to the axis of the drilled cylinders.