428 BOTANY. 
day’s journey north of Pike’s Peak. South of Pike’s Peak were 
some nearly fifteen feet high. None had the bark of Q. alba, but 
in other respects favored Q. robur rather than Q. alba. 
I know how easy it is to be mistaken. Though I do not think 
Mr. Watson is right, I am by no means certain of my own view. 
I write merely to suggest that full reliance be not placed on this 
supposed relationship without a fuller examination. A few years 
ago it would be deemed a matter of very little consequence ; but 
as the question of evolution has risen to such magnitude, such 
facts as these are worthy of the most careful scrutiny. As @ 
general rule it struck me that, accepting the theory of evolution 
as true, the plants of the Rocky Mountain region of Colorado 
favored a derivation from European rather than Eastern Americal 
forms, and that this oak was one of the instances. —THomss 
MEEHAN. 
Tue Formation or Ozone sy FLowers.—It has been found 
by Mantegazza (Rendiconti del Reale Istituto Lombardo, vol. ii. 
fase. vi., abstracted in Der Naturforscher, 27th April) that many 
essential oils, like that of peppermint, turpentine, oil of cloves, | 
lavender, bergamot, aniseseed, nutmeg, thyme, and others, v 
contact with the oxygen of the atmosphere in presence of sunlight, 
develop very large quantities of ozone. The oxidation of these 
oils is, in fact, a very convenient source of ozone, as they, waT 
small quantities, ozonize much oxygen. The action is strong" 
in direct sunlight, far less so in suffused daylight, and very we : 
-= at an end in the dark. The development of ozone which be f a 
begun in the light continues for a lòng time in darkness. © In! A 
same manner act eau-de-cologne, hydromel, and other | es 
tinctures on exposure to the solar rays. Experiments which Mai- 
tegazza has made on flowers with powerful perfume, canara 
narcissus, hyacinth, heliotrope, mignonette, and others, In * E 
vessels, proved that they also form ozone. Those aoe all. : 
perfume produced less ozone, those without scent none a 
Mantegazza believes that this important source foe eee 
hygienic value for the purification of the air of marshy 
— Academy. 
species has not yet been found in Colorado. ah 
hills to the eastward of Pike’s Peak; not abundantly, 
