THAT DRAGGING CHAIN

Evening Star, Issue 19615, 22 July 1927, Page 6

THAT DRAGGING CHAIN

WHY PETROL LORRIES GARRY IT SAUCERS OF STATIC ELECTRICITY "Hey, mister, pull up a minute. Your chain’s draggmg!” A pavement walker, laboring under the impression that he, a public benefactor, Inis just averted a tragedy, hails tho driver of a petrol tank lorry as he thunders past, “What's uj) now?” answers the driver, as he pulls up suddenly. Owing to the noise of tho engine, he has not grasped the significance of tho warning. “ Sec, you’ve a loose chain dangling on the ground. Will X hitch it up for you?” “ You can go to ,” cries the outraged driver, who has been stopped in this way many times. “ It’s tho chain’s business to be right where it is.” _ \ The pedestrian is so taken aback that the driver’s demeanor softens. “ That’s a sort of safety valve,” he adds. “Well, so long, and thanks all the same.” ,

Tho explanation is that the chain is used for grounding static electricity, a mysterious force which has never been harnessed. To the lay mind static electricity can be most simply defined us tho miniature fireworks display produced when one reverts to the old schoolday pastime of rubbing a cat’s fur the wrong way. If this experiment is carried out on a black cat in a dark room tho result can be definitely seen. Another way of producing tho phenomenon is by rubbing a lady’s hair briskly with a vulcanite comb, also in a dark room (which is so much more satisfactory in more ways than one). With regard to tho chaiu on petrol lorries, it should be explained more fully that it is used for grounding or earthing the static electricity produced by the frictional surging about of tho petrol within tho tank. The rubber tyres act as insulators, and unless this electricity gets away an explosion is often the ultimate result. In the early days of petrol tankers in America many “ mysterious ” accidents of this kind occurred. Whenever a tank lorry pulls into headquarters for a refill it is “ earthed ” by connecting the chain to a special earthing post. When interviewed this morning by a ‘ Star ’ reporter in search of information on tne subject a representative of the British Imperial Oil Company recalled the case of a Canadian medico, who, as a result of static electricity, was tho victim of a very nasty accident, the cause of which at tho time was most puzzling. One night the doctor received a sudden call to visit a patient. Ho was wearing rubber boots and a rubber coat lined with fur. No sooner had ho entered his garage than ho noticed a smell of petrol, and, gathering that the petrol tank of his oar was leaking, he began to make investigations. Suddenly there was a violent explosion, and tho doctor was so badly injured as a result of it that he was laid up for several weeks. The only possible reason for the mishap was that a spark of electricity had bean caused by the friction of the fur-lined coat against the gum boots. That spark was sufficient to set in action lira fumes of leaking petrol. I’coplo should bo warned against the practice of washing garments in petrol. Jf this process is carried out at all it should bo seen to that tho basin is cither in contact with a water tap or is standing, on mother earth. The friction produced by rubbing clothes together in petrol may otherwise produce a fatal spark. More sponging of clothes is quite safe.