THE spinning and twisting of real silk threads for the hosiery and silk weaving trade involves the processing of threads as small as two-thousandths of an inch in diameter. The throwsters, that is, the operators who twist silk fibres into raw silk or raw silk into thread, find that they can work much better and much more quickly when the threads are brilliantly illuminated by the light from electric discharge lamps. To avoid eye strain, the Factories Act which came into force in July 1938 has emphasized the necessity for adequate lighting in such cases. We learn from an article on factory lighting which appeared in the Electrician of March 24, that G. H. Heath and Co. of Macclesfield and an associated company, British Crepe, Ltd., said to be the largest firm of silk throwsters in Great Britain, after experimenting with many kinds of lighting, have recently adopted as standard throughout their factories the electric discharge lamps made by Siemens Electric Lamps and Supplies, Ltd., with very successful results. In one case a room at the factory was lighted by discharge lamps consuming a total of 4-7 kw. and giving approximately 13-15 foot candles, whereas with gas-filled electric lamps the same room would have required 14-5 kw., that is, more than three times as much, and would only have given a lighting intensity of 7-8 foot candles. The sizes of the Siemens “QH” lamps installed are 80 w. and 125 w., according to the size and height of the rooms. The economy effected in running costs is very noticeable.