Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/111

Rh Four cubic inches of brine were evaporated to dryness very slowly, in a heat which was not suffered to rise above 212°, and towards the close of the evaporation it was kept between 170° and 180°. The residuum was reduced to powder, and again kept for an hour in a heat of about 180°. The different brines yielded the following quantities of entire salt.

This variation in the strength of the different brines is probably owing to the mixture of the fresh-water springs in different proportions. Farley's pit, which is the weakest, is perhaps so on account of the brine not being agitated by pumping, whereby the lighter fresh water will only mix with the brine in the upper part of the pit: the bottle of it which I obtained was from near the surface.