Microscopes for Sale
Occasionally, surplus or duplicate items from my collection are offered for sale to finance new purchases. Please note that the collection shown here is not currently for sale. Unlike other online sales platforms, there are no unnecessary fees or overheads charged here, and the price is determined in advance or through fair negotiations. Any items that are offered for sale on this platform will also be posted on Instagram.
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Case-Mounted Pocket Microscope, Early 19th century
This is an early 19th-century pocket microscope of a relatively rare design. It is reminiscent of the so-called Cary-Gould pocket microscope, which was said to be designed by Charles Gould under the directorship of William Cary in his workshop. In reality, versions of the theme of the pocket microscope, including duplicates signed by different makers who were probably only retailers, were on the English and Continental market during the first four or five decades of the 19th century.
Tourmaline Tongs, ca. 1860
These Tourmaline tongs are coming with a set of specimens of mineral crystal specimens mounted in square paper-covered cork plates (provably by Steeg & Reuter), as seen here.
Tourmaline is classified as a semi-precious stone, and the gemstone can be found in various colors. Tourmaline crystals are highly birefringent, a crystallographic feature resulting in the split of a ray of light crossing the crystal outside its optical axis into an ordinary and an extraordinary beam, being polarized at right angles to each other. Tourmaline tongs are a primitive polariscope device having a transparent tourmaline crystal thin section in each half, mounted in cork in independently rotatable oxidized brass disks at the ends of a pair of spring tongs mounted with the transmission axes at right angles to each other. Specimens are slipped between the two tongs and observed by holding the system up to the eye. These specimens contain each a crystal slice set in a specific vibration axis of its optical indicatrix to yield an interference figure (seen in the photos taken with a cellphone camera through the instrument seen here). The device was invented by Jean-Baptiste Biot (1774-1862) as an inexpensive, effective, and easy-to-use polariscope. This early experimental work in physical optics, primarily concerned with studying the polarization of light and the birefringence of crystals, was the first step in creating the field of optical mineralogy.