From the book Maxims and Instructions for the Boiler Room [etc.], N. Hawkins, Theo. Audel and Co., New York, 1902:
“THE INSPECTION OF STEAM BOILERS.
Let it be clearly understood that if there were no steam generators using steam under pressure there would be no boiler inspection, and no licensing of engineers.”
[from “Snippets of Instruction,” in AIR 15:4.]