SiGERSON — On the Atmosjjhere. 
17 
Country Air (Plate V.). — In this Plate are represented specimens 
of the objects captured during an examination of the air of the country. 
With the exception of the acarus shown in fig. 22, they are magnified 
with ith object-glass. 
Fig. 1. The row of objects here depicted are droplets of dew, some of 
them being reduced in size for convenience' sake, whilst their contents 
remain magnified. It is seen that, although the dew has often been 
made the type of purity, it is, in reality, much adulterated with inchoate 
greenish matter (probably vegetable), with inchoate brown and dark 
matter (probably dust and soot), whilst there are some granules and 
minute batons whose origin it was impossible to tell. The dew, like 
the rain, washes the air. In one drop of dew collected off a leaf, where 
it could not have lain more than a couple of hours, a very lively 
monad was found disporting itself. 
Fig. 2 represents a group of globules or germs, whose origin I can- 
not tell. 
Figs. 3 and 8 are portraits of pollen-grains, four grains being occa- 
sionally grouped together. Fig. 5 is a grain of daisy-pollen. In 4, 
two germinating grains, with poUinic tubes prolonged, form a curious 
group. The pollinic tubes must have grown without penetrating the 
stigma; for, after having been once anchored, they would not be found 
uninjured in the air. They resemble germinating spores of Blasia 
pusilla. Fig. 7 is an undetermined object. 
In fig. 6, the egg of an animalcule of some kind is shown. 
Fungi found in the air form the assemblage of objects, ranging 
from figures 9 to 13, inclusive. Fig. 9 is seemingly a kind of mucor 
or mould, under which head we may class fig. 11. 
Fig. 10 gives the filamentous fragment with spores, detached from 
the interior of a Lycoperdon, or puff"- ball, knocked about and broken by 
the feet of cattle in the meadows. 
Fig. 12 represents some objects which were •captured whilst cross- 
ing a rural road. Evidently they were fungi ; but to what to attri- 
bute them, or how to call them, embarrassed me at first. However, 
some time after sketching them, I made an examination of the atmo- 
sphere over a potato field, in which the potato disease had declared 
itself in the blackened leaves and halms, with a view to ascertain whe- 
ther any specimens of the Botrytis infestans would be found in it. 
A breeze was blowing over the field, and shaking the tops. The 
result of my research was, that I not only discovered them (they are 
represented under Fig. 13), but was enabled immediately to identify 
the objects represented by Fig. 12, as being the same. They, indeed, 
appear to have been stragglers from this very field, and were wafted 
away to spread the disease to other fields, if we are to agree with the 
view that the potato murrain is due to this fungus. As it has been 
advanced by that distinguished cryptogamic botanist, the Eev. Mr. 
Berkeley, there is every probability of its accuracy. Taking this 
theory in connexion with the fact of the stragglers above-mentioned, 
which I found making their way from a centre of infection, the only 
K. I. A. PROC. — VOL. I., SKR. II., SCIKNCK. 
D 
