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THE FARMER'S MAGAZINE. 



still, instead of the largest percentapfe of nitrogen, 

 it has the smallest, and the largest of oxygen ; but 

 the proportions in which they unite produce one of 

 the strongest acids in nature. I bring this before 

 you because it is almost the only other form in 

 which nitrogen becomes the food of plants. Ni- 

 trate of soda employed as a top dressing, is com- 

 posed of nitric acid and an alkali, the base being 

 soda; and its great effect on vegetation is due to 

 the nitric acid and not to the soda. The experi- 

 ment has been tried again and again, and if soda 

 were the element that yielded the benefit, we 

 should not give £20 a ton, more or less, for nitrate 

 of soda, whilst we could buy salt which contains 

 as much soda for as many shillings. Mr. Pusey 

 used nitric acid in a diluted form in one of his 

 experiments, and the same effects were produced 

 as if he had applied nitrate of soda. Ammonia 

 and nitric acid both exist in the air. With regard 

 to the nitric acid, a Frenchman greatly startled 

 chemists by the announcement of the fact of a 

 great amount of both ammonia and nitric acid 

 existing in the atmosphere. But this only served 

 to show that no single experiment ought to be 

 relied upon, but ought to be tried by other chem- 

 ists before being received as an established fact. 

 Boussingault and Professor Way both found that 

 they could obtain from rain-water nothing like the 

 same quantity as the French chemist had succeeded 

 in obtaining. The experiment of the one had been 

 performed in the city of Paris, that of the two 

 others with rain collected in the country ; and the 

 larger quantity of ammonia, which in cities arises 

 from smoke, from the large consumption of fuel, 

 from dunghills, and decaying bodies, than in the 

 country, might create, in the atmosphere in the 

 neighbourhood of towns, more than double the 

 quantity in that of the country. This fact, in 

 itself interesting, also accounts for the great 

 amount of vegetation that succeeds frequent thun- 

 der showers in some root crops — not that lightning 

 has any direct influence; but a thunder shower 

 generally descends suddenly, and after a drought 

 of some little extent, and consequently brings 

 down with it whatever ammonia and nitric acid 

 exist in the atmosphere. Way found that there 

 was in a year's fall of rain per acre : — 



Nitric Acid. Ammonia. Total Nitrogen. 



(1855) (1855) (1356) (1855) (1856) 



lbs. 2.98 to 2.80 7.11 9-53 6.63 8.731 



There being from 44 to 46 lbs. of nitrogen in an 

 acre of wheat or barley, that quantity it will there- 

 fore be seen is considerably more than the rain 

 can bring down, and the French chemist had 

 possibly overrated the effect. It is thought by 



some that dew and fog are richer in ammonia than 

 rain, but although they are somewhat richer, yet 

 upon careful experiments it has been found that 

 the quantity of dew per acre deposited in the 

 ground is not more than 10 tons, whereas, the 

 quantity of rain is 2,500 tons per acre. Professor 

 Way, in his excellent paper on soils, has noticed 

 that strong soils or clay have a great power of 

 fixing ammonia; so, if we dilute a strong solution 

 of ammonia and throw it over a quantity of soil, 

 very soon all smell of ammonia will disappear. 

 This seems to be a very wise provision of nature 

 that a substance which costs so much money, and 

 is of so much value, should not, like other alkalies, 

 become rapidly soluble and soon washed out, but 

 should thus be retained in the soil for the uses of 

 vegetation. Not so nitric acid, although it also is 

 of so much value applied in a particular manner to 

 paiticular uses ; it is soluble, and, unlike ammonia, 

 soon washes out of the soil ; so much so, that I 

 would impress this observation on your minds that 

 you may not be led to throw it away, or to find 

 what you had done rendered useless. You may 

 apply ammonia as sulphate of ammonia, carbonate 

 of ammonin, or ammonia in the form of guano, 

 and it will be fixed by the soil without being 

 washed away; but if you apply nitric acid in the 

 fall of the year or in the winter, you run great risk 

 of a considerable portion being washed out of the 

 soil again. Tims it is that different results 

 and effects occur. Some may say, " It agrees with 

 my land excellently and answers my purpose, and 

 I can produce six bushels more per acre when 

 nitrate of soda is apphed." Others may say, "I 

 get nothing but straw — it has no good effect what- 

 ever." Now this greatly depends upon the mode 

 of application. Nitrate of soda should be used 

 only as a top dressing, and never applied to an 

 exhausted soil, nor unless there be vegetation then 

 and there to take up that which is so valuable, and 

 thus you run no risk of losing money in so valu- 

 able an ingredient. It will not do at all times to 

 estimate the value of manure by the quantity of 

 nitrogen ; for it was found by a late experiment of 

 Mr. Lawes, that a greater effect was produced by 

 nitrate of soda on barley, than by an equal quan- 

 tity of nitrogen in the form of sulphate of ammo- 

 nia. I have myself seen, continually, similar 

 effects produced upon grass and wheat, more 

 particularly on strong land. This also shows 

 that nitrate of soda should be applied late in the 

 season, and never upon poor and exhausted soil, 

 because it would act as a stimulant, supplying one 

 particular element of vegetation only, and stimu- 

 lating plants to put out their roots and extract from 



