Nitrate of Soda as a suhstitide for Guano. 391 



Peru. But Mr. Bollaert, our main authority, informs us that 

 nitrate is also found higher up the river Loa in the desert of 

 Atacama, which belongs, I believe, to the rival government of 

 Bolivia. It is further stated, though in a less authentic manner, 

 that saltpetre plains exist to the west of St. Luis de Potosi, in 

 Southern Mexico, with water communication to the Atlantic. In 

 all those remote regions inquiry has been set on foot through the 

 resident consuls by Lord Clarendon, and their answers will be 

 communicated to our Society; but in the mean while the Liver- 

 pool merchants, who have been naturally eager to share in the 

 guano trade, should not neglect to make exertions of their own 

 in these more promising fields. Whether they fetch us guano 

 or nitrate, we are now assured that they supply our land with the 

 same manure, differing indeed in name and in form, but identical 

 in substance and virtue. Such is the solid result established by 

 chemistry, and thus I hope to have made good what I ventured 

 to assert in the outset, that abstract investigation may sometimes 

 serve to guide us safely amid practical difficulties. 

 Pusey, Dec. 1853. 



N.B. — The amount of Nitric Acid and Ammonia contained in rain must be regarded as open to future 

 observation and correction. 



APPENDIX. 

 To Mr. Pasey. 



Dear Sir, — At your request I subjoin a few observations on the conditions 

 required for the formation of nitrates ; much regretting that, in consequence of 

 the approaching publication of the Journal, I have not time to present the 

 subject before you in a more perfect manner. 



For some years, in my lectures, I have endeavoured to direct the attention 

 of the farmer to the artificial formation of nitre, having felt somewhat sur- 

 prised that its importance has hitherto been so generally overlooked. 



I shall at present content myself with a brief explanation of the conditions 

 under which nitrates are formed. Whenever animal or vegetable matter, 

 gaseous, liquid, or solid, containing nitrogen, comes into contact with mild 

 calcareous or alkaline earths, the mixture being moist, and so porous that the 

 air^ can easily penetrate, after some time the nitrogen, under certain con- 

 ditions of temperature, is acted upon by the atmosphere, is oxidized, and is 

 converted into nitric acid, which at once unites with the calcareous or alkaline 

 bases present in the mixture. 



The temperature most suitable is from 58° to 68° Fahr., and the action 

 ceases at 32" Fahr., the freezing point. 



The instances of the oxidation of gaseous nitrogenous bodies are very com- 

 mon. The mortar of almost all old buildings, in any situation, contains a 

 greater or less amount o{ nitrate of lime, the nitric acid of which is produced 

 by the oxidation of ammonia, absorbed by the mortar from the atmosphere. 

 Another example is that furnished by an experiment of a French philosopher, 

 who suspended a piece of moistened and well-washed chalk over a basin of 

 putrifying blood, and who, after the lapse of some time, detected easily the 

 presence of nitric acid in the chalk. 



The oxidation of liquid nitrogenous compounds is also of ordinary occurrence. 

 The urine of any animal mixed with calcareous or earthy matter readily fur- 

 nishes nitrates by oxidation ; and even the urinary deposits of animals on 



