Wollaston hydrates

William Hyde Wollaston presented an early compilation of "equivalent weights" or combining masses (closely related to molar masses) in 1813. He drew upon some experimental data of his own and a large body of chemical analyses published by other scientists. This exercise deals with the water content of some hydrates. In what follows, Wollaston was talking about parts by mass, so read "grams" where he says "parts".

a) He reported that 56 parts water could be driven off from 100 parts of the hydrate called "Glauber salt." The anhydrous salt in this case is sodium sulfate, Na₂SO₄. Using a modern periodic table, find the molar ratio of water to anhydrous salt and determine the formula of the hydrate.
b) He reported that 14.8 parts water could be driven off from 100 parts of another hydrate. The anhydrous salt in this case is "muriate of barytes," known to us as barium chloride, BaCl₂. Using a modern periodic table, find the molar ratio of water to anhydrous salt and determine the formula of the hydrate.

Reference

William Hyde Wollaston, "A Synoptic Scale of Chemical Equivalents," Philosophical Transactions of the Royal Society 104, 1-22 (1814)

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