Evening Republican, Volume 23, Number 177, Rensselaer, Jasper County, 24 July 1920 — SPIDER’S THREAD HAS VALUE [ARTICLE]

SPIDER’S THREAD HAS VALUE

Practically Indispensable in the Construction of Telescopes for ths Astronomer. The threads of the garden spider are fixed by astronomers in their telescopes for the purpose of giving fine lines to the field of view, by which the relative positions of stars may be accurately measured. For a century astronomers desired to make use of such lines of the greatest possible fineness, and procured at first silver wire drawn out to the extreme limit of tenuity attainable with that metal. They also tried hairs (l-500th of an inch thick), and threads of the silkworm’s cocoon, which are split into two component threads, each only l-200th of an inch thick. But in 1820 an English Instrument-maker named Throughton Introduced the spider’s line. This can be readily obtained three or four times smaller than the silkworm’s thread, and has also advantages in its strength and freedom from twist. In order to obtain the thread the spider is carefully fixed on a miniature “rack,” and the thread, which at the moment of issue from the body is a viscid liquid. Is made to adhere to a winder, by turning which the desired length of firm but elastic thread can be procured.