AMMONIA AND NITRIC ACID IN RAIN-WATER. 
173 
the weather, are perfectly consistent in kind with the results obtained by M. 
Boussingault in his special examinations of rain falling unclei c 1 ere 11 c 
Constances, of the water of dews, of fogs, &c. Thus, M. Boussmgaul 
always found a very obvious connexion between the amount of rain wmen 
fell in individual showers, and the prnjtortion of ammonia in the water co - 
lected; there being more ammonia per million of the water the less the 
amount of the fall. There was also much more ammonia at the commence¬ 
ment of a shower than at the end of it, and after a drought than in continu¬ 
ously rainy weather; though a comparatively short cessation of the rain was 
sufficient again notably to increase the proportion in the water collected. In 
<he water of dews and fogs, again, he found the proportion of ammonia was 
very high. 
from the above facts it would seem, that the proportion of ammonia 
found in the aqueous deposits from the atmosphere was greatly dependent 
on thi> amount of those deposits ; or, in other words, on the degree in which 
they diluted the soluble matters brought down by them from the atmosphere, 
turning now more directly to the evidence of our own figures in reference 
to these points, it is at once obvious, that the period ot the year has of itsell 
40 direct influence on the proportion of ammonia in the. rain; for we find 
tow this is three times as great in the water of May 1853 as in that of May 
•> 1 ; the proportion found in the latter being the lowest, and that in the 
fonner nearly the highest, in our entire series of experiments. And that this 
directly due in great part merely to dilution, is obvious from the fact, 
whilst there was comparatively little difference in the actual amount of 
ttnmonia brought down over a given area in the two eases, yet with the 
“to proportion of ammonia in the rain of May 1851, the fall was nearly' 
JWw times as great as in May 1858. The largest proportion of ammonia 
'ottghout the entire series was, however, in December 1853; and here it 
m , seei1 m the second division of the J able, very neany me smallest 
6( , ri un ' 0l 'nt of ammonia washed from the atmosphere of any ease in our 
thatw b arin 8 >n mind these facts, it will be only what would be expected, 
Slid e , highest proportion of ammonia with prevailing northerly 
ttn Irrf rl y winds, and the lowest with prevailing southerly ami westerly 
latter 81nce die former arc generally coincident with a low, and the 
Vain!! hi s u . of rain, any supposed material influence ol the 
aa, 0Uh . ®yhe wind might probably much more properly be referred to the 
In th° . "dl* or in other words, to the degree of dilution, 
total fnfl ma V ,)er ’ **»ice with storms we have frequently a considerable 
toimionia 0rina *’ Q "» or emanation, or the slow or rapid condensation of 
“*''1, is n M P° n dm lessening of its amount by its conversion into nitric 
careful c ° n otlc . <! obvious on the face of the figures of the Table. Still, a 
the diff erUl ' OU owr notes as to the general character of the w eather 
AOWBonju in^M 1 taken in connexion both with the proportion of 
“own a t (jar. ' va te»* collected, and with the total amount of it brought 
prevalei, GrGU p Stason8 over a given area of land, seems to indicate that 
"to amou^ C r • bunder-storms has not of itself the tendency to increase 
0 mtr ogen brought down in the form of ammonia. And, even 
