A set of 11 wooden eyepiece mounts and adapters, some incomplete, and all without lenses.

Of these 11 pieces, one mount has a large thread, four a medium thread, and two a small thread, two are cocus wood adapters each with a large thread, one is made of light wood with a medium thread, and one is a threadless mount for a lens (probably not meant for an eyepiece) of light wood. Once included in this set though no longer was a small cocus wood eyepiece mount, with an internal thread and pitch adhering to it. All pieces have many dents and scratches.

William Herschel's eyepieces, made for him by his younger brother Alexander are outstanding because of their magnifying power which was exceptionally high for the time. In his 'Account of a Comet', read to the Royal Society in April 1781 (the comet in question was later confirmed to be Uranus) he referred to having 'ready at hand the several magnifiers of 227, 932, 1536, 2010, &c'. At the time a power of 270 was considered excellent, and his audiences disbelief at his claims of magnification was a serious hurdle in getting his discovery recognised.