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174 
REPORT—1854. 
supposing that the frequent occurrence of storms during the w armer months 
were found to be coincident with a large actual deposition of ammonia, it 
might still be a question whether such a result were not dependent on other 
characters of the season, or the conditions of the lower strata of the atmo¬ 
sphere, and their connexion with the surface, rather than upon those of the 
higher strata, or the circumstances more directly leading to the development 
of the storms. At any rate it is worthy of remark, that in the month of 
May 1854, which was characterized by the occurrence of many, and sotno 
very heavy thunder-storms, and by three times the fall of rain of the cor¬ 
responding month of 1853, we have still a less total deposition of ammonia 
over a given area, than in either May 1853, or in the average of the other 
mouths, the rain of which was experimented upon: and, with regard to the 
influence, on the other hand, of the minor aqueous depositions upon the 
amount of ammonia deposited, our notes and figures do not show any increase 
in the actual amount of ammonia so deposited, which could be attributed to 
them irrespectively or other circumstances, but rather that their more direct 
effect is upon the proportion of the ammonia to the generally less actual 
amount of water, as already pointed out. But, whilst the proportion of 
ammonia per million of the water collected is thus seen to depend more on 
the mere amount of the fall than ou the period of the year, it must obviously 
at the same time be mainly influenced by the total uinouut of ammonia 
actually brought down over a given area; and this again would seem to 
have tittle direct or uniform connexion, either with the amount of the fall, or 
with the period of thu year merely. Thus, as already stated, with three times 
as much ram in May ia.54 as in May 1853, wc have nearly the same, or even 
™ ' if 98 tota . »"‘n° n, a deposited, with the larger fall: nnd again, com- 
nf March and April 1853 with those of the same months 
amnnnf < ,• l0ug « true that in these cases we have the larger total 
th.r i a T°r, brought (l(nv " with the larger fall of rain, it is seen that 
n* nwJ? »® Man* 1854 only one-seventh, and in April 1851- only one-fifth, 
month * «* C | deposited over a given area as in the corresponding 
.i .*.° ' • It*then, as above alluded to, upon other circumstances 
tnan either the amount of the fall or the period of the year, that the amount 
oi ammoma brought down by the aqueous deposits from the atmosphere 
mainly depends. 1 
r..lT,?«i ,ng l °- t the , . nore .' ,ire < ; t application of the figures to an important agn- 
nur^n ^ 0,,Sld .‘’ ra | 10 "’'! ,na y be stated that the amount of nitrbgen which 
Bnl.r-r^n /i“ e r " ho ?* d WM brou § ht down in actual solution from the atmo- 
XhnM 6 ° rUJ °[ amwon ^ was adequate to supply but a small proportion 
1 ag ? ann «alamount of it contained in the produce of a continuously 
of til p n - ° ground * We ,uust seek therefore for some other source 
rain sni in 8 ,? ° UI U, "" a,luretl cro P s - than that which is brought down in 
ammonal . jjf h*. 1 " 0 ' aqueous deposits from the atmosphere, in the form of 
soil or of'tl p ’i"\ tl0 | Ut hc f enteriu 8 into the question of the power ot the 
comnliniU f ? themselves, to take up the ammonia or other nitrogenous 
beZou^h? d r ° m ' e 1 a,ni08|jher ' s independently of the amounts which would 
for sunnolfrVl 1 ? d,r *? * olution water, there seems to be good ground 
more liber-d^nn*! 1 - ano J, ,er com P°und of nitrogen, namely nitric acid, is a 
ev^amrniaTelr ° f mtr ° ge0 t0 *'*'"» atmospheric -urce, than 
detected 1 nil’ri^■!£! becn . alreari y mentioned, various experimenters have 
we to*bt«l fnr^d » ^ in rain * water « yet it is to M. Barral that we 
which couhl ll , quantitative estimations of nitric acid in rain-water 
which could lead to the supposition, that this is probably an important 
