CAN SODA REPLACE POTASH AS A MANURE. 51 
theoretical in their character, of MM. Bineau, Bonssingault, and G. 
Ville. Amongst the publications which have largely contributed also 
to our knowledge of the practical utility of nitrate of soda, we must 
not forget the numerous and very remarkable papers of Dr. Pusey.* 
Chemists and agriculturists, men of science, and practical farmers, 
all seem to be at present unanimous in ranking nitrate of soda as one 
of the most efficaceous agents of vegetable production. 
Before the unfortunate Leblanc had discovered the admirable process 
by which soda is readily obtained from sea-salt, advantage was taken, 
in the manufacture of this useful alkali, of the property possessed by 
marine plants of extracting and secreting in their tissues the soda 
contained in sea-water. The combustion of these plants furnishes 
an ash, of which carbonate of soda is one of the principal components. 
Amongst the vegetable matters fitted for the extraction of this alkali, 
the ash of the Barille, a plant cultivated on the coasts of Spain, yields. 
from 20 to 50 per cent. of carbonate of soda. Although less rich in 
alkalies, the ash of the varech affords also considerable quantities. 
The abundance of soda in the ashes of these vegetables, joined to the 
disappearance of plants containing soda in the interior of continents 
(at least when the soil is destitute of salt,) indicates clearly the fact 
that soda is essential to their existence. Now, considering the close 
relationship between soda and potash, it is not without interest to 
inquire how far these alkalies are capable of replacing one another ; 
and, in addition, whether a substitution of this kind affects im any 
way the development of vegetable life. 
M. Payen relates that the leaves and branches of Mesambrianthe- 
mum cristallinum, collected at the Island of Teneriffe for the extrac- 
tion of soda, are dotted with glands containing a solution of the 
oxalate of that alkali; whilst, in passing inland from the coast, these 
glands are found to contain oxalate of potash. 
The venerable M. de Gasparin cites also, another vegetable species, 
in which potash appears to replace soda in a still more complete 
manner, without detriment to the vigour of the plant. This is the 
Salsola tragus, collected as a “soda plant,” in the district between 
Frontignan and Aigues-Mortes. This species extends far up the 
valley of the Rhone, and, according to M. de Gasparin,t is of equally 
vigorous growth in its most inland station, as in the neighbourhood of 
* Journal of the Royal Agricultural Society of England, vols. xiii, xiv, and xv. 
+ Cours d’Agriculture ; 3e. édition, T, 1, p. 106. 
