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Handbook for translators of Spanish historical ... - University Library

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PALEOGRAPHY<br />

violet from the visible rays. In the center <strong>of</strong><br />

the housing, rxinning from the front to the hack is<br />

a tvinnel, cylindrical in shape, with a diameter <strong>of</strong><br />

2 1/2 inches. The lens <strong>of</strong> the camera, to be used<br />

<strong>for</strong> the ultra-violet photography, protrudes into<br />

this tunnel, which acts consequently as a lens hood. 23<br />

Q-reat advantages are attributed to this type <strong>of</strong> lamp, such<br />

as lower cost, generation <strong>of</strong> less heat, greater actinic<br />

value <strong>of</strong> the ultra-violet radiation, which permits shorter<br />

exposure, and evenly distributed illumination.<br />

The same investigator later developed a "Palimscope,"<br />

based on the lamp Just described, as a source <strong>of</strong> ultraviolet<br />

illumination <strong>for</strong> the study <strong>of</strong> palimpsests. It consists<br />

chiefly <strong>of</strong> a quartz tubing concentrated in a spiral.<br />

Provided with a handle, this source <strong>of</strong> ultra-violet light<br />

can be used as a flashlight. Its uses need not be confined<br />

to the reading <strong>of</strong> palimpsests. 24<br />

Light filters are essential when photographing manuscripts<br />

under ultra-violet radiation. They are also used<br />

in photographing stains and in reading faded writing with<br />

the mercury vapor lamps used <strong>for</strong> illumination when making<br />

photostatic reproductions. The following filters are to<br />

be used with ultra-violet lamp:<br />

1. Eed XM9U. Purple rUJ-iiJ-V Ultra, WXb^a, No. mu • 597^ %j.n i . Transmits, xxcbuomx wo , 3,650 u , wi/w i, A, ul- ixJ."<br />

tra-violet free freely, 4,050 A violet, and extreme red<br />

at about 7,200<br />

Heat Hesisting Red Purple Ultra. No. 587. Transmits<br />

the same as the preceding filter, but appears somewhat<br />

darker.<br />

Violet Ultra, No. 586. Transmits 3,650 A ultra-violet:<br />

and in a thickness <strong>of</strong> seven mm. or greater<br />

transmits no visible red.<br />

Red Purple Corex A, No. 986. Transmits ultra-violet<br />

at wave-lengths 3,100 a and shorter, and absorbs<br />

most <strong>of</strong> the visible light <strong>of</strong> wave-length longer than<br />

4,250 A.<br />

^^<strong>Library</strong> Journal, September 15, 1934, Vol. 59, p. 691.<br />

^^L. Bendikson, "A Cycle <strong>of</strong> Ultra-violet Light Source <strong>for</strong><br />

Various Uses", <strong>Library</strong> Journal Jan., 1936, Vol. 61,<br />

pp. 16-17. _19_

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