Sand Blast
2 of the 6 encyclopedias on this shelf carry an entry for Sand Blast. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
one of the most wonderful uses of sand, by means of which glass, stone, metals, or any other hard substance may be cut or engraved. If a stream of sharp sand be let fall from a high box (as high as the ceiling of a room) through a tube on to a plate of glass held under it, the sand will cut away little grains of the glass till at length the whole surface will be cut or scratched and it will look like ground glass. If, instead of cutting the glass all over, it is wanted to engrave a pattern or figure on it, the workman has only to cover the parts of the glass which he does not want cut with a stencil plate made of leather, rubber, paper, wax, etc., for the sand will not cut any soft substance. By this means only the uncovered parts are cut, and when the stencil is taken off the pat- General Tilghman of tern will be seen. Philadelphia, who first found out how which the to do this, made a machine in sand is blown on to the things to be cut by a blast of air or steam. Glass signs, glass globes for lamps and gas burners, tumblers, goblets, and other glassware may be engraved in this way very fast, and with the most beautiful designs. Metals and stones also may be cut by means of the sand blast, which will not cut it only scratch the surface, but will away to any depth. The marble tombstones put up in the National cemeteries to the memory of soldiers killed in the war were made in this way. American
The Encyclopedia of Founding (1892)
The process of engraving, cleaning, boring, and cutting glass, metals, and other substances by forcing or blowing sand, emery, powdered quartz, granules of iron, etc., upon the surface by means of steam-pressure or air-blast. Corundum 1 1/2 inches thick has been pierced by a jet issuing at 300 pounds pressure. It is also used for cleaning castings, graining of zinc-plate, cutting letters on stone and glass, frosting silverware, and many other similar purposes.
What Has Changed in the Last Century
Both accounts treat the sand blast purely as a marvel of cheap cutting power, and Collier's rightly credits Benjamin Chew Tilghman of Philadelphia, who patented the process in 1870. What neither mentions is the cost to the men holding the nozzle: blasting silica sand releases respirable quartz dust, and by the mid-20th century silicosis had made the practice notorious. Britain prohibited sand as a blasting abrasive in most factory work under regulations of 1949, the US NIOSH recommended a ban on silica sand as an abrasive in 1974, and industry has largely shifted to garnet, steel grit, coal slag, aluminium oxide or glass beads, with operators in air-fed hoods. For the fine cutting and boring the 1892 entry admired, high-pressure abrasive waterjets and lasers now do much of the work, while blasting survives mainly for cleaning, surface preparation and decorative frosting.
Written for this edition, 2026.