A way to break easily and speedily the hardest rocks, communicated by the same person, as he received it from Monsieur Du Son, the inventor

Through the invention of breaking with ease, and dispatch, hard rocks, may be useful on several occasions, the benefit is incomparably great, that may thereby accrue to those, who have adits of passages to cut through hard rocks, for making passage for water to run out by, in mines of lead.