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POPULAR SCIENCE REVIEW. 
gave an average angle with the meridian of more than 34°. Their mean was 
18° west. The remaining 29 specimens bore ninety-one leaves, which made 
with the meridian the following angles, viz., seven made angles greater than 
35° ; fifteen, angles between 35° and 20° ; sixteen, angles between 20° and 8° ; 
twenty-eight, angles between 8° and 1° ; and twenty-five, angles less than 1°. 
Of the sixty-nine angles less than twenty degrees, the mean is about half a degree 
east of the meridian. The error of azimuth, from my want of means to deter- 
mine the time accurately, may have been as much as three times this quantity. 
One half the leaves bear within about haK a point of north ; two-thirds within 
a point. The magnetic decimation was about 6° east. The observations were 
made when the sun was about on the magnetic meridian. 
Respiration of Floivers. — The conclusions which M. Cahours forms as the 
results of his late inquiries upon this subject may be thus stated : — 
1st. AU flowers confined within a limited atmosphere of ordinary air con- 
sume oxygen and develope carbonic acid, the proportions varying according 
as the plant has a perfume or has not. 
2nd. Cceteris paribus, the greater the temperature the greater the amount 
of carbonic acid developed. 
3rd. Generally, when the flowers have been collected from the same plant, 
and equal weights of them are exposed to light and darkness, the carbonic 
acid formed by those in the dark will be in larger quantities than that 
evolved by them in the light. 
4th. When the ordinary air is replaced by oxygen the difference is more 
prominently marked. 
' 5th. Flowers which are in process of development, give off more carbonic 
acid than those which are fully formed — a fact which is explained by reference 
to the greater amount of vital action going on in the one than in the other. 
6th. Flowers exposed to the influence of an inert gas disengage small 
quantities of carbonic acid. 
7th. Of the various parts which compose the flower, the pistil and stamens 
(being the structures which expend the greatest amomit of force,) consume 
the greatest amount of oxygen and set free the largest quantity of carbonic 
acid. 
Presence of Vegetable Spores in the Atmosphere. — In the course of the impor- 
tant discussion upon the subject of spontaneous generation, some very impor- 
tant facts have been elicited by the experiments of Dr. J. Lemaire, who has 
communicated the results of his investigations to the French Academy. The 
atmospheric vapour of several localities was collected, condensed, enclosed 
with a portion of ordinary air in sealed tubes, and then microscopically exa- 
mined, and in every instance large quantities of vegetable and animal forms 
were observed. In one case the air and vapour were collected at Fomainville, 
at a height of nearly 300 feet above the level of the Seine, in a locality of a 
most salubrious character. At the moment of condensation, the water con- 
tained, independently of small particles of dust and filaments of various sorts, 
a few ovoid spores and a great many small semi-transparent bodies, which 
were seen in making other experiments also. Twenty-four hours after this, 
bi-jugated cells, bacteria, vibrions, and monads were observed. At the expira- 
tion of forty-eight hours the spores and cells had disappeared, the bacteria 
and vibrions became motionless, but the monads, which were then very 
