A surprisingly popular page on our museum website.
A surprisingly popular page on our museum website.
Newton's optical legacy was particularly profound in the field of spectroscopy. In 1666 Newton discovered that white light was made up of the basic colours of the spectrum. This disproved the earlier belief that colours were caused through white light being somehow modified. The sun, however, is not the only source of celestial light.
Thus, in the late eighteenth century, William Herschel (shown in the image to the left) experimented with the spectra produced by the light from other stars. In 1783 he placed a prism at the eyepiece end of a 20-foot reflecting telescope and in 1798 he investigated light from six bright stars including Sirius and Arcturus.
In 1802 William Hyde Wollaston (1766-1828) refined Newton's prism experiment by reducing the light source to a narrow slit 1/20th inch wide. He noted dark lines across the spectrum and at first assumed that these were the divisions between the seven colours.
Joseph Fraunhofer (1787-1826) discovered hundreds of similar lines whilst testing glass telescope lenses. Eventually he counted 576. Fraunhofer had gained experience as an optician working at the Utzschneider optical institute near Munich. He also reproduced spectra in laboratory conditions that differed from that of sunlight in not being continuous ('bright-line' spectra, with dark gaps between the lines).
Gustav Robert Kirchhoff (1824-1887) explained Fraunhofer's discoveries in 1859. He established that sunlight is just one of a number of glowing forms of matter (liquid or solid) that produce a continuous spectrum; bright-line spectra are caused by gases. Each element, whether found in gaseous, liquid or solid form could be analysed and a different tell-tale set of line positions identified. It was now possible to determine the chemical composition of celestial bodies and this gave way to a new science of astro-physics.
The image to the right is item LDBOA1999.327, a Spectrometer by Philip Harris Ltd of Birmingham made of black painted metal and brass with a tripod base. It is contained in a wooden case with a hinged door that opens at the front. With its shiny brass it is a very beautiful instrument. Despite this there is no certainty that it is any older than the 1950s when such devices were still advertised in the company's catalogue. The company that came to bear this name was originally based in the Digbeth area of the city and started by Thomas Ellis, a Surgeon, in 1817. At that time the person Philip Harris would have been only 15 or 16 years old. He joined Ellis in 1825. The company traded as a wholesale Chemical Laboratory Company occupying its Bullring site until 1889 moving to 144-146 Edmund Street at some time around the turn of the 19th and 20th centuries.
When the nights draw shorter we can always revert to that traditional parlour game of 'name the most famous optometrist'. According to his book Everything You Never Wanted to Know and Never Bothered to Ask by our College Fellow Brian Ariel FCOptom, there are several candidates from the worlds of sport and entertainment such as the cricketing optometrist Geoff Lawson, an ex Australian Test Bowler and former coach to the Pakistan National Team, or the musical optometrist Rudy von Gelder, a legendary recording engineer for Blue Note jazz records. There are infamous optometrists such as Reinhardt Schwimmer, a member of the Moran gang shot dead by Al Capone’s gang in the St Valentines Day Massacre in Chicago, 1929, or optometrists who crop up in unexpected circumstances such as Robert Graham, who founded the first 'genius' sperm bank in California.
To Brian's list we might add the first optometrist to be appointed a Peer of the Realm, Lord Charnwood, or Will Griffiths, the first optician to be elected a Member of Parliament (though not the first to stand for that office). Some would plump for John Sutcliffe, in terms of international honours the most decorated optometrist of the twentieth century. Or how about George Giles...to a whole generation of practitioners quite possibly the most memorable optometrist they ever encountered?
Historians of science would have little problem in nominating their candidate. The most famous optometrist is John Browning (c.1830-1925). He had already built a reputation for manufacturing scientific instruments of the highest quality for use across the disciplines of physics (including astronomy), chemistry and biology. Furthermore, unless you buried your head in the sand, you couldn't fail to hear about these. A prolific publicist, he and his successors placed about 1500 advertisements in the prestigious journal Nature between 1869 and 1930, which have been the subject of an important academic study in their own right. Whilst his business prospered he also became an early published authority on tricycles. Then, in or before the 1890s when he was already in his sixties, Browning was at the forefront of the new movement for 'scientific' sight-testing. In 1895 he helped form the British Optical Association, the world's first professional and examining body for optometry and had the honour not only of being elected its first President but of being entered into the Register as Member No 1. John Browning is thus the world's first professional optometrist.
This object, a Spectacle-mounted Jeweller's Spectroscope symbolises John Browning perfectly. It is a form of spectroscope, the instrument on which his reputation rested primarily. Unusually it is spectacle-mounted, which points to his work as an ophthalmic optician, and its use was probably for jewellers in the examination of gemstones, which serves as a reminder of how many opticians also worked in the jewellery business in the late 19th and early 20th centuries. It probably dates from around 1900-1910 which places it slap bang at the pinnacle of his career, the era when he lent his personal prestige to the formation of a new and forward-looking profession.
If anyone can furnish any more specific information on this particular item which the museum has just acquired, we would be very grateful if you would contact us.
Next up is item LDBOA1999.3515 Grace's Spectroscope, made by John Browning, 63 Strand, London in the late 19th century. This has a brass cylindrical body with screw lenses and milled adjusting wheel. Mr Grace has recently been tenatively identified as a near neighbour and sporting friend of John Browing, after whom it seems he may have named the instrument.
This is a diffraction spectroscope. John Browning's Prismatic Instruments Catalogue (March 1923) states:
This instrument was originally designed for meteorological use and has for many years been known as Grace's Rainband Spectroscope, but is equally suitable for all the various purposes for which Direct Vision Spectroscopes can be used. It has greater dispersion than the miniature type and the mechanical focusing adjustment will be found useful for faint lines and bands as distinct from the well-marked absorption bands, for which the simpler patterns of the Miniature type suffice.
John Browning was noted for his fine spectroscopes though he also sold a wide range of other optical equipment. He was also the first President of the British Optical Association 1895-1900.
Our next image is item LDBOA1999.3516 a Rain-band spectroscope & case, late 19th century, again made by John Browning, 63 Strand, London, with a brass cylindrical body, telescopic tube and screw lenses. It is contained in cylindrical cardboard case with slip top and no surviving end pieces. It's quite short. That's a five-centimetre scale shown next to it.
A rain band spectroscope was for viewing the broad red band that raindrops produce in a spectrum; these were popular items, not necessarily for serious scientists. Note the wording of this advertisement for a slightly earlier instrument from an 1861 issue of Chemical News:
Crookes' Spectroscope...with the kind and valuable assistance of W. Crookes, Esqu. F.C.S. so well known for his successful researches upon the spectrum, we have been enabled to produce a most efficient, portable and convenient instrument...Crookes' Pocket Spectroscope for tourists...Spencer Browning and Co., Patentees, 111 Minories, E.C. Established 100 years.
Finally comes item LDBOA1999.2761, an example of Thorp's Spectroscope & case, by R. & J. Beck Ltd, London. A brass D.V. Diffraction Rendering Spectroscope, cylindrical, with adjusting wheel and brass screw-cap on the end. It also features a tiny round lens. Contained within a black leatherette hinged case with clasp, lined with blue velvet and purple silk, this is a beautifully presented object that it almost seems a pity to remove from its case.