COMMON SODA. 89^ 



that work the reader is referred for farther in- 

 formation as to the success that has attended 

 its use, — the quantity applied, — its mode of 

 application, &lc. Here it is only our province 

 to explain the chemical effects produced by 

 this substance on vegetation. 



Common Soda is an impure sub-carbonate of 

 soda, that is, soda united with carbonic acid 

 gas. In this state it is sometimes found in na- 

 ture, but the principal source of supply arises 

 from lixiviating the ashes of burnt sea- weed, 

 such as kelp and barilla, &c. Extensive ma- 

 nufactories exist for the production of this ne- 

 cessary article in Scotland and various other 

 parts of the kingdom, and it is also produced 

 as a refuse matter from other salts of soda, in 

 the alkaline manufactories throughout the 

 country. 



It is to the presence of this salt that the fer- 

 tilizing properties of the ashes of sea- weed may 

 be attributed, and its addition to the compost 

 heaps spoken of in page 82, would furnish the 

 alkali necessary for fixing the nitrogen, and 

 thus afford a more certain result than can be 

 obtained from the use of wood ashes. The 

 combination however in this ca§e would be a 

 nitrate of soda instead of nitrate of potash. 



The use of this salt as a manure would be 

 valuable to any soil deficient in alkaline matters, 

 to w^hich by its solution in the first rain it 

 would afford an ample supply, whilst the car- 

 bonic acid gas, that would at the same time be 

 9 



