418 
POPULAR SCIENCE REVIEW. 
The Formation of Ozone by Floivers, — It is stated by the Academy 
that Mantegazza has found (“ Rendiconti del Reale Institute Lombardo,” 
vol. iii. fasc. vi., abstracted in u Der N aturforscher,” April 27) that many 
essential oils, like that of peppermint, turpentine, oil of cloves, lavender, 
bergamot, aniseed, nutmeg, thyme, and others, when in 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 con- 
venient source of ozone, as they, even in small quantities, ozonise much 
oxygen. The action is strongest in direct sunlight, far less so in suf- 
fused daylight, and very weak or at an end in the dark. The development 
of ozone which has been begun in the light continues for a long time in 
darkness. In the same manner act eau-de-cologne, hydromel, and other 
.aromatic tinctures on exposure to the solar rays. Experiments which 
Mantegazza has made on flowers with powerful perfume, such as the 
narcissus, hyacinth, heliotrope, mignonette, and others, in closed vessels, 
proved that they also form ozone. Those with fainter perfume pro- 
duced less ozone, those without scent none at all. Mantegazza believes 
that this important source of ozone is of hygienic value for the purifica- 
tion of the air of marshy districts. 
Absorption of Water by Leaves under certain circumstances. — The state- 
ments of Duchartre and others, that leaves absorb neither water with 
which they are wetted nor vapour from surrounding air, have been fully 
confirmed by M. Cailletet so far as respects the foliage of plants es- 
tablished in the soil and supplied with moisture by the roots. But the 
revival of wilting leaves when sprinkled or enclosed in a moist atmosphere, 
however ingeniously explained away, always seemed to bear testimony to 
absorption. And M. Cailletet’s experiments go to show, incontestably, 
that foliage does absorb liquid water (but not watery vapour) when supply 
by the root fails or is arrested. His experiments were made by introduc- 
ing a leafy branch into a glass vessel with a double tubulure, filled with 
water, the increase or diminution of which was accurately and delicately 
measured by a manometer. A Bromeliaceous epiphyte, which grew under 
his care for six years, suspended by a fine wire without root, he found, 
was able to absorb and fix more than a hundredth part of its weight of 
water upon a short immersion. His note upon the subject was presented 
to the French Academy, and is printed in 11 Ann. Sci. Nat.,” vol. xiv. p. 243. 
Change of Habit.- —It is stated in “ The Garden,” that the Loranihus 
macranthus of New Zealand, parasitic there upon trees of Rutacece and 
Violacece , is deserting these in favour of trees introduced by the European 
settlers, such as hawthorn, plum, peach, and especially laburnum, which 
was introduced as lately as 1859. Its flowers are abundantly visited by 
the European honey-bee. 
Double Flowers of Ranunculus Rhomboideus. — A correspondent of the 
u American Naturalist” has found several perfect double flowers of this 
plant in Floyd County, Iowa. One of them was transferred to a bed in 
the flower-garden, where it throve well, and increased to a clump six 
inches in diameter, which, the next spring, was perfectly enveloped with 
the little bright yellow flowers. No seeds were produced; and during 
the two or three seasons in which the plant was cared for there was no sign 
