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tion reddened litmus paper; and probably the free acid 

 exerted a prejudicial effect, and interfered with the re- 

 sult. 



Soot doubtless owes a part of its efficacy to the 

 ammoniacal salts it contains The liquor produced by 

 the distillation of coal contains carbonate and acetate 

 of ammonia, and is said to be a very good manure. 



In 1 808, I found the growth of wheat in a field at 

 Roehampton assisted by a very weak solution of ace- 

 tate of ammonia. 



Soapers' waste has been recommended as a man- 

 ure, and it has been supposed that its efficacy depend- 

 ed upon the different saline matters it contains; but 

 their quantity is very minute indeed, and its principal 

 ingredients are mild lime and quicklime. In the soap- 

 ers* waste from the best manufactories, there is scarce- 

 ly a trace of alkali. Lime moistened with sea water 

 affords more of this substance, and is said to have 

 been used in some cases with more benefit than com- 

 mon lime. 



It is unnecessay to discuss to any greater extent 

 the effects of saline substances on vegetation; except 

 the ammoniacal compounds, or the compounds con- 

 taining nitric, acetic, and carbonic acid; none of them 

 can afford by their decomposition any of the common 

 principles of vegetation, carbon, hydrogene, and oxy* 

 gene. 



The alkaline sulphates and the earthy muriates 

 are so seldom found in plants, or are found in such 

 minute quantities, that it can never be an object 

 to apply them to the soil. It was stated in the begin* 



R 2 



