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PROPERTIES OF SODA.

PROPERTIES OF SODA,

Soda differs particularly from potash by the following proper-ties. Jn the fire it is rather more fusible. When exposed to thecontact of the air it attracts water and carbonic acid, but it doesnot liquefy like potash, it merely acquires a pasty consistence,and at last crumbles iuto powder. It is not altered by light. Itattracts sulphur and sulphurated hidrogen more feebly. It ad-heres less strongly to the acids. It fuses and dissolves aluminemore easily. All its other properties, its volatilization by a veryhigh degree of heat, its acrid causticity, its solubility, its com-binations with sulphur, &cc. resemble those of potash.

METHOD OF OBTAINING SODA.

Soda like potash is procured by lixiviation from the ashes ofburnt plants, but only from those which grow upon the seashores. The variety of plants employed for this purpose is veryconsiderable. In Spain, soda is procured from the. differentspecies of the salsola salicornia and Lath maritima. The zasteramaritima is burnt in some places on the borders of the Baltic.In this country we bum the various species of fuel; and in Francethey burn the chenptmdium m anti mum.

The soda thus procured is more or less pure according to thenature of the particular plant from which it is obtained. Thegreatest part however is a true carbonate of soda.*

In order to obtain it in a state of purity the carbonate of sodamust be treated like potash of commerce with lime and ardentspirit, as described before.

Remark. ..It is curious that some plants, which in their nativeso'! yield only potash, afford also soda if they are cultivated inthe neighbourhood of the sea, or on land occasionally inundatedby it.

* The methods of preparing soda for the English market, we have stated ioNicaolson’s Journal, for Augult, iSoz.