342 The Exhalation of Ozone by Flowering Plants. [April, 
The average temperature of these apartments was as follows: 
Economic house 80°, temperate house 55°, fern house 65°, fore 
ing house 75° Fahr. 
The first experiments were commenced Oct. 14, 1882, and con- | 
tinued till the end of November. The atmosphere of the main 
hall was tested on twenty-five days during this period, the Schoen- 
bein giving negative results except on Nov. 29th and 3oth, when 
this paper showed a slight blue tint. The papers were placed ot 
the branches of the highest plants, moistened both when they : 
were suspended and after being taken down, and the duration of d 
the experiments varied from four to twenty-four hours, 
The guaiacum test paper showed a very slight reaction for ; 
about one-half of these observations, but unfortunately this p 
could not be relied upon, while the results with the Schoenbeit 
were too meager on which to base conclusions. A few see ; 
made during this series simultaneously in the forcing and ci l 
houses with negative results. It should be stated that "p | 
periments were being conducted at a time when penn f 
tors were daily attracted to the hall by the indescnit * l 
of the plants, and hence it was thought not unreaso e 
pose that any ozone which might have been generated 5 | 
plants was consumed in oxydizing the organic matter pe d 
the air by the visitors, for it should be remembers gree 
tenkofer has pointed out, ozone is never detectable "a 
phere of occupied dwellings. Though these experiment jot 
barren of results, when the above circumstances arè Mi — 
account they were not much to be wondered at. d 
. : i latter part 0° 
The next series of observations began in the i March 
ruary, and were continued through the months i 
April of the past year. During the month of ro 
only an occasional visitor admitted, in March a abf 
very few, while in April the number was Comm 
though not by any means numerous. These exp sphere 
results somewhat more encouraging. The ae 
exterior was simultaneously tested for the sake of ¢ a 
the two situations. The observations wer ee í 
days in the main hall, Schoenbein papers ee sie ae 
these gave “very slight” reactions, while by e „adone“ 
during the same time six “ very slight” r e house 
Twenty-four tests of the air in the tempera 
