SODA. 
197 
in solution in mineral springs, and is often one of the ingredients of sea water. In some 
cases it accompanies the carbonate of soda, when its occurrence may be referred to the mu¬ 
tual decomposition of common salt and sulphate of magnesia. This action is especially 
observed at low temperatures : it is in winter that Glauber’s salt is found in the greatest quan¬ 
tity in certain lakes.* 
This salt, mixed however with various other saline matters, is found in the form of an efflo¬ 
rescence on the limestone below the Genesee falls at Rochester, in Monroe county. It is also 
held in solution by the water of the Longmuir spring, in the city of Rochester. 
NATRON. 
[From the desert of Natron, where it was formerly obtained.] 
Soda Carbonatee. Hauy. — Carbonate of Soda. Clcavdand and Phillips. — Hemiprismatic Natron. Jameson. — 
Hemipnsmatisches Natron-Salz. Mohs. — Natron. Beudant, Shepard and Dana. 
Fi e- 19 - Fi s- 20 - Description. A saline substance, 
usually occurrring effloresced and in 
powder ; but it is easily crystallized 
artificially, when it assumes the 
form of the octahedron with a rhom¬ 
bic base, truncated at the summit 
(Fig. 19). The primary form, according to Hauy, is that represented in Fig. 20. P on P 
143° 8'; P onP' 113° 54b 
Natron has an alkaline reaction, effervesces with acids, and is soluble in about two parts of 
cold water. It gives the flame of alcohol a yellow tint, by which it can be distinguished from 
carbonate of potash. The crystals of natron effloresce in the air ; those of trona do not. 
Composition. When entirely pure, it contains carbonic acid 32.30, soda 46.70, water 
14.00, but it is almost always mixed with portions of sulphate of soda and common salt. Its 
formula is NaC0 3 +Aq. 
Uses. This salt is largely employed in the manufacture of soap and glass. It is now 
prepared artificially by the decomposition of Glauber’s salt. 
LOCALITIES. 
This salt occurs in needleform efflorescing crystals on walls in the cities of New-York and 
Albany, where it is probably produced by the reciprocal action of carbonate of lime and com¬ 
mon salt. The fact that such a mutual decomposition does take place, was first proved by 
Berthollet, who carefully examined the subject, and communicated the results of his observa- 
* Beudant. Traite Elementaire de Mineralogic, I. 647, 
