Action of the Atmosphere upon newly-deepened Soil. 435 



ledge on the subject, yet, as some important investigations in 

 this country have since then been published by Mr. Lawes, it 

 may not be out of place here to give some of the results that 

 have been arrived at. 



Ammonia found iu 1,000,000 parts of air, by — 



Kemp \ 3-680 . 



Graeger 0-323 



Fresenius (by niglit) 0-1(39 



(by day) 0-098 



-rr-ii r TO ■ i f interior of Paris .. .. 0-024 



V ille, irom 16 expermients { ■ ^ u • r, aot 



' ^ \ environs of Fans . . 0-021 



Ammonia found in 1,000,000 parts of rain-water, by — 



Barral, mean of 5 montbs' observations at Paris (con-l 0.400 



firmed by Boussingault) ) 



Boussingault, mean of 6 months' observations in open 1 o-744 



country in Alsace J 



Lawes and Gilbert, mean of 14 months' observations ini q.oqa 



open country at Pothamsted J 



2s itric acid found in 1,000,000 parts of rain-water by — 



Barral, mean of 5 months' observations at Paris .. 16-250 



Mr. Lawes has also investigated the proportions of nitric acid in 

 rain-water, and, although he did not consider his experiments 

 satisfactory enough to be published, yet he has stated that their 

 tendency is to confirm the fact of the larger proportion of 

 nitrogen occurring under this form than in that of ammonia, 



Boussingault has also found the water of dew and fogs to be 

 much richer in ammonia than rain-water. 



As the air generally sweeps over the ground at a considerable 

 velocity, each particle of the surface is continually brought into 

 contact with a fresh supply, and the well-known powers of the 

 earth to aljsorb the ammonia so presented to it shew that a 

 considerable quantity must thus enter into its pores. 



Ammonia has a powerful affinity for water; according to 

 Thos. Thompson, water, at the common temperature and pres- 

 sure, takes up 7bU times its bulk of this gas, and under strong 

 pressure it is absorbed in still greater quantity. Under a pres- 

 sure of 6<j atmospheres ammonia becomes a fluid ; it is also 

 liquefied at a temperature of — 40^. Ammonia has the properties 

 of an alkali or base, uniting witli acids to form salts, which are 

 generally soluble in water ; some of them are, like itself, volatile 

 at the ordinary temperature, while others require a strong heat 

 to decompose them. The ammonia of the air probably exists in 

 tiie form of a carbonate, and ^ir. Way found that, if air charged 

 with ( arlxmate of ammonia, so as to be highly pungent, is j)asscd 

 throutjh a tube hlicd with small fragments of (by ilay, evei-y 

 particle of this gas is arrested; and, in the same manner, if into 

 a bottle filled with air similarly imj)regnated a little ordinary 



