Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/238



Although I found it expedient, before advancing farther in the examination of the water, and in order to regulate my steps in the progress of the inquiry, thus to trace the various plans which seemed adapted to the purpose, yet I apprehend it would be superfluous to detail here in regular succession all the trials which arose from these different methods. I shall therefore confine myself to such as belong more immediately to my object; and in relating them, shall consider singly and under separate heads, the various ingredients of the water, stating, as I proceed, the proportions in which they were ultimately obtained.

§ VIII. Sulphat of Iron.

The presence of iron, in the state of sulphat, having been abundantly proved by the preliminary experiments, the next step was, to ascertain the proportion of this salt in a given quantity of the water. The first reagent which I tried for this purpose, was prussiat of potash; but after many trials which afforded uncertain and discordant results, I convinced myself that this test, however useful for detecting the presence of iron, is quite inappropriate when our object is to ascertain the quantity of that substance.