May 19, 1923 
Spores in the Upper Air 
603 
Tabi^S III .—Results of exposing slides, coated with vaseline or glycerine jelly, simul¬ 
taneously by hand for j minutes on June 14, and vaseline-coated slides by hand for 10 
minutes on July 5, from airpla^ies in the vicinity of a 40-acre tract containing large 
numbers of escaped common barberry bushes, near Waukegan, III. 
Slide 
No. 
Date- 
Altitude 
above 
around. 
I<ocation. 
Number of spores c 
on si 
Aeciospores. 
>f Puccinia graminis 
ides. 
Urediniospores. 
Vaseline. 
Glycer¬ 
ine jelly. 
Vaseline. 
Glycer¬ 
ine jelly. 
1922. 
Feet. 
X 
June 14 
100 
Over bushes... 
4 
6 
0 
0 
% 
...do. 
Jf 000 
.do. 
5 
IK 
3 
T 
•3 
4 
.. .do. 
000 
6 
6 
X 
A 
3 
5 
...do. 
5,000 
X 
7 
0 
0 
6 
.. .do. 
7 »ooo 
3 
0 
0 
3 
7 
.. .do. 
10, 000 
.do. 
0 
4 
0 
0 
8 
...do. 
xa.ooo 
0 
X 
0 
0 
xo 
.. .do. 
3,000 
10 miles away... 
4 
5 
I 
3 
XX 
. do. . T 
3,000 
T5 miles away.. 
3 
3 
0 
X 
13 
.. .do. 
3,000 
35 miles away . 
X 
0 
0 
0 
X 3 
July 5 
100 
Over bushes . 
X 4 
e 
XA 
.. do . 
100 
.do . 
8 
3 
2 
xe 
.. .do _.. 
1,000 
.,_do ... 
7 
A 
x6 
.. .do. .... 
1,000 
.do . 
xo 
0 
X 7 
.. .do . 
3,000 
II 
4 
x8 
.. .do . 
3,000 
.do . 
9 
3 
19 
.. .do . 
6,000 
.do . 
4 
3 
30 
...do . 
6i 000 
._do . 
7 
3 
31 
.. .do . 
3,000 
Over Fort Sheridan. .. 
0 
3 
33 
.. .do . 
3,000 
X 
I 
On a single one of the slides, exposed for five minutes at an altitude 
of 10,500 feet (about 2 miles), near Fort Crook, Nebr., 224 spores were 
caught. On a similar slide exposed for the same leng^ of time at an 
altitude of 8,000 feet, 827 spores of known identity were caught, and in 
addition there were about 200 spores of unidentified forms, making the 
total about 1,000. 
The highest altitude at which slides were exposed was 16,500 feet, or 
more than 3 miles above the siuf ace of the earth. This slide was exposed 
between Waco and San Antonio, Tex., on April 28, 1921, and two ure- 
diniospores of what appeared to be Puccinia triticina were caught. It 
would not be safe, however, to conclude that spores normally occur at this 
height, as only a few flights were made at such extreme elevations. 
Spores are very numerous up to about 11,000 feet, but at higher altitudes 
they apparently are relatively scarce. 
The number of spores caught per slide varied according to the method 
and place of exposure. Fewer spores were caught in the mechanical spore 
trap than on the slides which were exposed by hand. This probably 
was due to the fact that the spore trap was attached to the struts just 
above the upper surface of the lower wing, and it is quite probable that 
the air currents were deflected in such a manner as to miss the slides to 
some extent. By'referring to Table II it wdll be seen that more spores 
were caught on slides which were exposed by hand from the cockpit than 
on those in the spore trap on the lower wing. In future work it probably 
would be well, therefore, to expose the slides on the fuselage or under 
the lower wing. 
