474 The Exhalation of Ozone by Flowering Plants.  |May, 
change the color of these test papers very much as ozone does, 
To exclude the possibility of the change in color being due to 
the nitrous oxides, we tested the air during the latter set of ex 
periments on the outside of the case simultaneously, and found 
that the papers in this situation gave only one “slight” reaction, — 
and even though this occasional reaction on the exterior had 
been due to the presence of the nitrous oxides, they could not | 
have caused the much more striking and constant tests obtained 
on the inside. Again, it is not at all likely that the plants gem 
erated nitrous oxides, which in turn might have changed the test 
papers, for there is nothing in all vegetable physiology to support 
such an hypothesis. Moreover, it is all the more improbable that 
nitrous oxides caused the blue colorations, since they did not do 
so when foliage plants were employed. l 
We do not wish to say dogmatically that all the changes inthe 
test papers were due to ozone, but from the many beautiful reac- 
tions obtained, and the systematic precautions taken to preclud 
the action of other substances known to answer to like tests, 
will not be denied. that the chief agent in changing the papers ] 
was ozone. I was unable to detect the odor of ozone upon WAM | 
Professor Leeds lays so much stress, but Mr. Miller thought he 
could detect its presence. It must be borne in mind that W 
amount of plant life within the case was probably too small t 
generate sufficient ozone to make it perceptible to the sensè 
smell. 
It would appear certain from these experiments, that the gs 
which are so actively engaged in carrying on the ipon t r 
tions, as, for example, transpiration, have nothing whatever a 
with the production of ozone. But, on the other hand, it is t0 i 
flower that is delegated this highly important, though | 
hitherto unthought of, function in plant life. _ e : 
Can we, from the facts derived from these observations, por i 
any definite conclusions respecting the nature of this i 
Is the cause to be sought in the functions of the petals oF at 
formation of the seed? Let us here recall how o 
produced artificially, and it will be remembered that ca 
by suspending phosphorus in moist air. Now it !S pe hates. * 
the ashes of seeds contains large quantities of the phosp rapid 4 
follows that during the formation of the seeds the 
metastasis of phosphorites in the form of ph 
