390 



Nitrate of Soda as a substitute for Guano. 



Swedes per Acre. 



Tons. cwts. 



No manure 16 8 



Nitrate, 160 lbs 20 8 



Ammonia sulph., do. ... 20 1 



The result of the whole comparison appears to be this. Foar- 

 grass-land, saltpetre is equal to guano if a small quantity of 

 phosphates and perhaps of potash be added. For wheat it is 

 probably inferior to guano if applied in autumn, because more- 

 liable to be washed down by rain, but preferable if used in spring,, 

 because less liable to evaporation in drought, and spring is appa- 

 rently the best season for giving purchased manures to wheat. 

 For turnips superphosphate is superior generally to either guano 

 or nitrate, and has the great advantage over both that it can be 

 used with the water-drill, and that, being so used, it gives us in 

 the south a rapid growth which makes up for our late seed-time; 

 but if nitrogenous matter be also required, we now know that 

 nitrate can be spread broadcast over turnip-land as successfully 

 as guano itself. We have therefore found a substitute for guano 

 in the three great departments of husbandry, the culture of Grass 

 of Roots, and of Corn. 



The comparison of nitrate with guano is even more important 

 this year than it was a twelvemonth ago. Then our object was. 

 to lower the price of guano by bringing into competition with 

 it another article not sold under monopoly. Now, the recent 

 survey of the Chincha islands shows that we have to fear a rise 

 in the price of guano preceding a total cessation of the supply,. 

 The possession, therefore, of an equivalent is more desirable^ 

 and now that we have found that equivalent, the increased supply 

 of cubic saltpetre is more urgent, and to that point the enterprise 

 of our merchants must next be directed. This salt we know 

 occupies the surface of a plain 150 miles long, the Pampa of 

 Tamarugal, separated by only 10 miles from the Pacific. Un- 

 fortunately, however, those ten miles wear so rugged a surface^ 

 that, although a railway is being constructed from the port of 

 Iquique, to a height of 3000 feet inland, it cannot be continued 

 to the refinery ; so that the coals for refining the salt, and the 

 salt when refined, must still be carried on the backs of mules 

 to and from these southern Salitres. But to the north of Iquique 

 is the mouth of the river Pisagua, which skirts the Pampa 

 not very far from the northern Salitres, affording of course a level 

 line for a railway in the direction required. On the south, again, 

 the river Loa offers the same facilities, passing near some 

 newly-discovered nitrate beds. All these sources, however, have 

 unfortunately one common defect — they are subject to the same 

 government which owns the guano islands, the government of 



