CROOKES’ SPECTROSCOPE IN MINIATURE, English, c. 1875, signed “John Browning, London.” This fine little spectroscope has a central trapezoidal box containing the glass prism, and two 4″ (10 cm) long tubes, one with extending tube containing the two-element eyepiece, the other with extending tube containing the simple adjustable slit. Each tube can be adjusted slightly for tilt with respect to the prism. Spectra are clearly visible. The instrument is in very fine condition, with its beautiful clear lacquered finish to the brass. It possibly had been stand-mounted at one time.
This is a diminutive version of the spectroscope patented by Sir William Crookes in 1861. The large version was manufactured by Spencer Browning and Co., and was stand-mounted with horizontal collimator tube; it was exhibited at the 1862 International Exhibition. One example is in the Whipple Museum in Cambridge, a second one in the Power House Museum in Sydney. But the makers also advertised “a most efficient, portable and convenient instrument…Crookes’ Pocket Spectroscope for tourists….” Spencer Browning and Co. are listed in the London directories until c. 1870, and John Browning on his own, at the same address, from c. 1872. We are aware of one other miniature example of this form.
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David and Yola Coffeen both have enjoyed academic careers, as planetary astronomer and as linguist/educator. But since 1982 (yes, 1982!) they have been full-time dealers in early scientific and medical instruments, under the name Tesseract. Selling primarily by catalogue (over 100 issued so far) they also have a web presence at www.etesseract.com, and can be contacted at [email protected]
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