If such steam engine or boiler or an appurtenance thereof is found to be in charge of, or operated by, a person not duly licensed as an engineer or fireman, and, after a lapse of one week from such time, it is again found to be so operated by an unlicensed person, it shall be deemed prima facie evidence of a violation of the preceding section.
Mass. Gen. Laws ch. 146, § 47
Prima facie evidence of violation of statute
Official source: Massachusetts Legislature. Reproduced from public-domain Massachusetts statutes; confirm against the official source for the current text. Not legal advice.