Note 20 — Chapter XXXII · Spring;—spinning;—salt mine.

I now formed a particular conjecture as to the nature of the crystallizations shooting out on all sides, and especially from the arch roof; they could scarcely be of that species of rock crystals produced by the slow filtering of water falling in drops and coagulating in succession, and seldom found in excavations exhibiting so dry a nature, nor ever with so many of the crystals perpendicular and perfectly smooth. I was impatient to evince the truth or falsehood of my opinion by an experiment, and discovered with great joy, on breaking a portion of one of them, that I was in a grotto of sal gem, that is, fossil or rock salt20, found in the earth in solid crystallized masses, generally above a bed of spar or gypsum, and surrounded by layers of fossils or rock. The discovery of this fact, which no longer admitted a doubt, pleased us all exceedingly. The shape of the crystals, their little solidity, and finally their saline taste, were decisive evidences.