918 
FACTS AND OBSEKVATIONS. 
eludes, from numerous investigations, that all these substances 
constitute the nitrogenous food of plants which grow in 
aqueous solutions. As to the changes which they may un¬ 
dergo in the soil, he thinks that a new series of researches 
must be made to determine this.— Ibid. 
How Light affects the Decomposition of Carbonic 
Acid by Plants. —In the Comptes-Rendus of August 9, a 
paper is published by M. Prillieux detailing the results of 
experiments made on plants with gaslight, electric light, and 
magnesium light. The experiments were conducted on 
aquatic plants; the stem of the plant being cut across, and 
thus allowing the escape of bubbles of oxygen to the surface ; 
these could then be readily counted. He found that whilst 
in a given time sunlight caused the disengagement of twenty- 
two bubbles, in the same time under the influence of electric 
light only eleven bubbles w^ere disengaged. Other lights 
furnished less. But still, as all the lights caused the disen¬ 
gagement of oxygen, it shows—the author thought—that 
these sources of light contain the same elements as sunlight. 
— Ibid. 
The Chemistry of the Air. —In the report just issued 
by the Inspector under the Alkali Act, the inspector gives 
the following as a summary of conclusions in reference to the 
state of the air: ‘^The rain from the sea (Western Islands) 
contains chiefly common salt, which crystallises clearly. The 
sulphates increase inland before large towns are reached. 
The sulphates rise very high in large towns, because of the 
amount of sulphur in the coal used, as well as decomposition. 
When the air has so much acid that two or three grains are 
found in a gallon of the rain-water, or forty parts in a million, 
there is no hope for vegetation in a climate such as we have 
in the northern parts of the country. Free acids are not 
found with certainty where combustion or manufactures are 
not the cause. Experiments in the direction indicated above 
may enable us to study and express in distinct language the 
character of a climate, and certainly of the influences of 
cities on the atmosphere .*”—Fifth Report published by Spot- 
tiswoode, and presented to both Houses of Parliament.— 
Ibid, 
Wax of the Ear. —M. Petrequin shows that the wax 
of the ear is variously compounded in different animals; 
thus, in man, its base is potash; in the dog, lime; and in 
the horse, magnesia. 
