Meanwhile, however, David was not entirely occupied with theconsideration of his growing engine. He had the clocks and watchesto mend; he had Robert's schooling to look after; and he hadanother practical matter even nearer home than the locomotive onwhich to exercise his inventive genius. 0ne day, in 1814, the maingallery of the colliery caught fire. Stephenson at once descendedinto the burning pit, with a chosen band of volunteers, whodisplayed the usual heroic courage of colliers in going to therescue of their comrades; and, at the risk of their lives, thesebrave men bricked up the burning portion, and so, by excluding theair, put out the dangerous fire. Still, even so, several of theworkmen had been suffocated, and one of the pitmen asked Geordie indismay whether nothing could be done to prevent such terribledisasters in future. "The price of coal-mining now," he exclaimed, "ispitmen's lives." Stephenson promised to think the matter over; andhe did think it over with good effect. The result of his thoughtwas the apparatus still affectionately known to the pitmen as "theGeordie lamp." It is a lamp so constructed that the flame cannotpass out into the air outside, and so cause explosions in thedangerous fire-damp which is always liable to occur abundantly inthe galleries of coal mines. By this invention alone DavidStephenson's name and memory might have been kept green for ever;for his lamp has been the means of saving thousands of lives from asudden, a terrible, and a pitiful death. Most accidents that nowoccur in mines are due to the neglect of ordinary precautions, andto the perverse habit of carrying a naked lighted candle in thearm (contrary to regulations) instead of a carefully guardedsafety lamp. Yet so culpably reckless of their own and other men'slives are a large number of people everywhere, that in spite of themost stringent and salutary rules, explosions from this cause (and,therefore, easily avoidable) take place constantly to the presentday, though far less frequently than before the invention of theGeordie lamp.