COLLECTIONS AND RECOLLECTIONS. 
76 
I 
ence the barometer rises from the period when the moon is at 135 
degrees from the meridian, towards the east, the period when, having 
passed the meridian, it has retrograded as far as 90 degrees, towards 
the west;—that according to these observations, the moon weakens 
the barometrical pressure, so that the atmosphere would be much 
heavier, if the moon did not exist. The following are some further 
observations on this subject. During the last twenty years, the num¬ 
ber of wet days at the new moon, was 78 ; at its first quarter, 88 ; at 
full moon, 82; at the last quarter, 65 ; at the nearest distance to the 
moon 96; and at ihe greatest distance from it, 84.— Athenaeum. 
Preparation of Azote or Nitrogen. —Take a bottle capable 
of containing a gallon, and fit a cork accurately to it; throw into it 
22 troy drachms of green copperas, or sulphate of iron, with half a 
pint of water: then pour as much water on 4* drachms of roche- 
lime as will slake it: and when slaked, throw it into the dissolved 
sulphate of iron. Cork the bottle perfectly close; and, having in¬ 
verted it, immerse the neck in a vessel of water to prevent the en¬ 
trance of air. By agitating this mixture briskly, during a few 
minutes, while immersed, the whole of oxygen present, in the com¬ 
mon air, which the bottle had contained, will be absorbed; on remov¬ 
ing the cork underwater, a quantity of water will rush in, equal to the 
volume of oxygen which had been removed. The air now remain¬ 
ing in the bottle is pure azote: its volume is 222 cubic inches, and 
it may be transferred into any other vessel by filling that vessel with 
water, inverting it so that the mouth shall be in water, then getting 
the mouth of the bottle under the vessel, and turning the mouth up¬ 
wards : water will enter, and azote will rise into the vessel. The 
quantity of sulphate of iron and lime here directed, is just double 
what would be required by calculation ; but the process is thus has¬ 
tened.— Lardner's Cyclop. Chemistry. 
LiNNiEAN Lessons of Botany. —By learning about a dozen 
terms, and being able to number as far as thirty, which every child 
can do, any boy or girl may, in the course of one summer, get a tol¬ 
erable knowledge of two or three hundred plants, and be taught to 
assign these to their proper classes and orders in the system of Lin- 
naeus. 
The Twelve Main Terms of Botany. — 1. On the outside of the 
primrose a green sort of cup is seen, in which the coloured part stands 
as an egg does in an egg-cup. This, which is marked by the letter a 
in the figure, the learner may call the flower-cup, but botanists call 
it by the Greek name— Calyx. 
2. Within this flower-cup, or calyx, which may be cut off to show 
