AMMONIA AND NITRIC ACID IN RAIN-WATER. 
175 
natural or climatic source of supply of nitrogen available for the growth ol 
plants: and scanty as it yet is, still our daily increasing knowledge as to 
the occurrence and properties of ozone tends to enhance the probability of 
well a view. It was hence a chief object of this investigation to determine 
'Ur quantities of the nitric acid as well as of the ammonia, in the rains col¬ 
lated at Rothamsted. and to estimate from these the sum of the nitrogen 
•applied by both, in relation to the average amount of it yielded in our 
^manured crops. Unfortunately, however, in consequence of the ditficulties 
winnected with the quantitative estimation of very small amounts of nitric 
arid, and especially owing to the existence of nitrogenous impurity in some 
of the re-agents employed, though in proportions which for many purposes of 
dialysis would be immaterial, tin* results arrived at on this head ure by no 
nituns satisfactory or conclusive, or such as to justify a record of the nume¬ 
ntal results obtained. 
lire process adopted was as follows. Large quantities of the rain-water 
"’tre ev ap° ra ted with an alkaline carbonate several times to dryness, and the 
^‘d res 'due was carefully collected and weighed after drying at 212". The 
jj er '^ a g e of nitrogen in this solid matter was then sought to be deter¬ 
ged by Dumas’ direct-volume method of combustion with oxide of copper. 
• ot only, however, were the results of duplicate analyses much more clis- 
^Tant than fheyshould have been, but the actual amounts of nitrogen indi- 
!o | "ere in some cases so exceedingly high, that suspicion was raised as 
Hie .T" 1 ? die re-agents employed; and it afterwards appeared, that 
f r ° xltJe °' C0 PP er » which bad been prepared from the nitrate, was not free 
ini Hei°r' )0 i S 0 n * tro 8 en which yielded it up in the combustion. Hut 
°** l * IR errwr which may have arisen from this cause, it must 
racy J' • • die P rtic css itself is not well calculated to attain the accu- 
V 1 Sl )ch an investigation ; and in fuel, that an accurate method 
is uill tetei 'miuation of small quantities of nitrogen, or rather of nitric acid, 
^ great desideratum. 
[lu Heric'^ eat ’ t ' Hln ‘ for the reasons stated, we refrain from recording the 
a . Ves . u h 8 yet obtained in regard to the amount of nitric acid in the 
general inj^ In ^ • *}or can we with full confidence vely even upon their 
to ti, e el Ufl ' l ? Ut . l0ns ’ j n tlie discussion of the important questions, with a view 
which we' ni'T 0t wl,lc h dm investigation was chiefly undertaken, and to 
cautionary 8 1 ! I0 P R to recur on Honi, ‘ future occasion. After these pre- 
U ur nitric 0 ^ Sei ’vationft, however, we may mention, that if the. indications of 
whilst the i) CU l ' ete tnuuations maybe trusted at ull.it would appear that 
«f thuiul " Ce,lta ^ e am * actun ' amount of ammonia might be less in the 
^tric acid t!r '| ,or,ns > and when there is a large fall of rain, the amount of 
•torms. The^* 10 ° lher lian,1 > is probably increased under the influence of 
°/ 'utrogen j.« CSU , *°° would further lead to the conclusion, that the amount 
“Sbly great 0 ' 1 ® u ^ own hy the rain in the form of nitric acid, was con- 
P°hit again b • f n so deposited in the form of ammonia. On this 
Resting L U i Wlt hoat relying confidently on the indication, it may still be 
°' Tn in th e ran >Sei (- Vl 'i’ ^ ,a . t with the very small amount of ammonia brought 
e *ainir lc d ft ° l *ie winter and spring months of 1 853-54-, so far as they 
J" 10 acid result' ^, 'T. °h were succeeded by such an abundant harvest, the 
^ n Usual ’ , u 8 them as they stand, show a much higher amount 
i u ^ Tabl es i« «!'« • in f l uest iou. It is true, that a study of uur Meteor- 
Iclimatic to show that other and more obvious and mea- 
firesn^^^ion sin lll , ans ,,la terially conduced to such a favourable result, 
aiu? ^ eQ hance tl> p Ce tlier ® can he no doubt, that nitrates, applied as manures, 
D itrio m °- Unt °f nitm^ r ° 1 1 °* P^ ants hy virtue of the nitrogen they contain, 
ac *d, must be c** rT ou 8ht down from the atmosphere, in the form of 
onsidered to have an important influence on vegetation. 
