EXPOSITION
Necessity is the mother of invention. Finding the Nile water continue utterly undrinkable, the Egyptians bethought themselves of a means of obtaining water to which they never had recourse in ordinary times. This was to dig pits or wells at some distance from the river, and so obtain the moisture that lay in the ground, no doubt derived from the river originally, but already there before the change of the water into blood took place. This, it appears, remained water, and was drinkable, though probably not very agreeable, since, owing to the nitrous quality of the soil in Egypt, well-water has always a bitter and brackish taste. It sufficed, however, for drinking and culinary purposes during the "seven days" that the plague continued (Exodus 7:25).