Silencers for Pneumatic Drills The Metropolitan . Paving Committee is
no doubt right in pointing out in its annual report that the use Of rock drills in breaking up concrete roads is necessary. At present the only alternative, it appears, to the intoler- able nuisance of having roads in London perpetually " up " is the intolerable nuisance of the ear-splitting pneumatic drill. But the committee points out that a number of silencers for attachment to drills have been produced with fairly satisfactory results, though apprer ciable noise reduction involves much loss in efficiency: Once more we are faced with the choice of evils. The committee expresses a pious hope that makers will persevere with their experiments and succeed in pro- ducing effective silencers. The best way to accelerate this process would be to make the use of silencers compulsory. It is no mere question of measuring utility against annoyance. Noise in excess creates not merely irritation but very definite injury to health.