Engraving Machine

Author:  B. C. Tilghman
Source:  US Patent 108,408
Doc ID:  1870000
Year of Publication:  1870
Abstract:  
My invention consists in cutting, boring, grinding, dressing, pulverizing, and engraving stone, metal, glass, wood, and other hard or solid substances, by means of a stream of sand or grains of quartz, or of other suitable material, artificially driven as projectiles rapidly against them by any suitable method of propulsion.