Appendix.

76 i

muriatic acid, anil the mixture boiled for half an hour, which precipitates carbonateof lime and alumina. This precipitate being dried, the lime is to be separated byacetic acid, and the alumina that remains dried and weighed ; so that by subtract-ing its weight from the original weight the proportion of sulphate of lime isascertained.

To estimate the contents of the muriatic solution, add to it ammonia as long asit throws down a reddish precipitate, which is" the iron united with a portion ofmagnesia. The magnesia is to be separated by acetic acid, the precipitate beingpreviously dried by exposure to the air, in a heat of 200°, and the solution addedto the muriatic solution j and to determine the weight of the iron, it is to be re-dissolved in muriatic acid, then precipitated by an alkaline carbonate, and dried andweighed.

Sulphuric acid is now to be added to the muriatic solution; and the sulphateof lime, thus obtained, is to be heated to redness, and weighed ; setting down forevery 100 grains of it 74 of carbonate of lime. From the solution the magnesia islastly to be separated by subcarbonate of soda, dried and weighed ; then evaporatethe remaining solution to dryness, and wash the residue with distilled water so as todissolve the muriate of soda. This residue is subcarbonate of magnesia, the weightof which, when dried, must be added to the former ; which gives the entire weightof the subcarbonate of magnesia.. Mineral acids exist in mineral water sometimes uncombmed, but more generally

combined with alkalies and earths, forming sulphates.

a. Sulphuric acid is readily detected by muriate of barytes, when it does notexceed the millionth part of the water. To render this test certain, however, themuriate must be diluted ; the alkaline carbonates, if the water coniain any, mustbe previously saturated with muriatic acid ; and the precipitate must be insolublein muriatic acid. The hydro-sulphureis are precipitated by muriate of barytes, buttheir presence is easily detected by their odour.

The proportion of sulphuric acid is easily estimated by saturating it with baryteswater, and heating the precipitate to ignition ; every 100 grains of this sulphate ofbarytes indicate 34 of real sulphuric acid.

J. The Sulphates contained in mineral waters are six in number, and are incompatiblewith the following salts placed in the opposite column.

, J Nitrates of lime and of magnesia.

Fixed alkaline sulphates J Muria(es of lim<J aud of magnes ; a>

C Alkalies.

■^ Carbonate of magnesia.

(_ Muriate of barytes.

( Alkalies.

1 Muriate of baryte3.\ Nitrate, muriate, carbonate of lime.

(^Carbonate of magnesia.

f Alkalies.Sulphate of magnesia - < Muriate of barytes.

(.Nitrate, muriate of lime.

{Alkalies.Muriate of barytes.Earthy carbonates.1. Sulphate of soda. —To detect this salt, first evaporate the water to one haV, andadd lime-water as long as any precipitate falls. This precipitates all the earthsexcept sulphate of lime, whicli may be separated by evaporating the fluid till itbecomes concentrated, then adding a little alcohol, and after filtration a littleoxalic acid. If lime-water produces a precipitate in the water thus treated, imme-diately, or after a little alcohol be added, either sulphate of potash or of soda is pre-sent. To determine which, add acetate of barytes, which will precipitate sulphateof barytes : then filter and evaporate the filtered fluid to dryness, and dissolve theresidue by digesting it in alcohol, and evaporate to dryness. If the sulphate besulphate of potash, the dry salt thus obtained being acetate of potash, will deli-quesce ; but if it be sulphate of soda, the acetate will effloresce.

The proportion of the alkaline sulphates is found by precipitating their acid, bynitrate of barytes, from the water purified as above. If soda be the base of thesalt contained in the water, for every 100 grains of this precipitate ignited, set

Sulphate of lime

Alum