44 REPORT—1857. 
ments, gradually assuming circular orbits, would ultimately form a ring similar 
to that around Saturn; and as this change advanced, the light should constantly de- 
cline until it ceased when the ewther partook of the motion of the fragmentary host, 
and became almost insensible to their pressure. It is to occurrences of this kind, 
which must occasionally take place in the wide domains of creation, that we may 
ascribe the appearance of temporary stars, and in doing so, we obtain a satisfactory | 
explanation of the various peculiarities which they exhibit. ‘The existence, on our 
own sphere, of the ether which acts so important a part in the scene of celestial won- 
ders is indicated by certain electrical phenomena. On its presence seems to depend 
the evolution of light attending the passage of electricity through the vacuum of an 
exhausted receiver, and the light of the aurora borealis appears to be evolved by ! 
electric action from the zthereal fluid, which arrives at the polar regions from space. 
Tt is only by this hypothesis that we can account for the effect of a shooting-star 
during an aurora, in lighting up certain parts of the vaults of heaven not previously 
illuminated (see Humboldt’s ‘Cosmos’ on Aérolites). 1t thus appears that the subtle 
medium which fills space is not to be regarded as a mere impediment to planetary 
motion, but as a useful agent in the course of Nature’s operations, and as indispensable 
to our existence as the appendages of air and water which roll around our planet. 
CHEMISTRY. 
On Ozone. By Professor T. ANDREWS. 
On the Heat of Combination of Acids and Bases. By Professor ANDREWS. 
On the Amount of Nitrogen in the Alga. By Professor James Apsoun, MD. 
On some Compounds of Cyanogen. By Professor JAMes Apsoun, M.D. 
On the Composition of the Iron Ores of the Leitrim Coal Field, with some 
Remarks on the Advantages of that District for the Manufacture of Iron. 
By P. Bucuan. 
On the Condition of Thames Water, as affected by London Sewage. 
By R. Baryes, M.D. and W. Ovxine, M.B., FCS. 
The authors had, for a period of nearly six months, made consecutive weekly 
examinations, microscopical and chemical, of ‘Thames water, taken at high and low 
tide from the middle of the stream at Greenwich. From their experiments it appeared 
that the pouring in of the contents of drains did not affect Thames water so seriously 
as was generally considered, inasmuch as the greater part of the sewage become de- 
stroyed by the innoxious processes of oxidation and vital development, while only a 
small portion underwent the process of putrefaction, properly so called. The amount 
of organic matter present did not appear to be any criterion of the offensiveness of 
the water, seeing that it existed for the most part in the state of living organisms. 
The authors found invariably a greater amount of organic matter in high, than in 
low water. 
On Urea as a Direct Source of Nitrogen to Vegetation. 
By Cuarves A. Cameron, M.D. 
The author showed that nitrogen was as available as food for plants, when a con- 
stituent for urea, as in its ammoniacal combination; or, in other words, that urea, 
without being converted into ammonia, may be taken up into the organisms of plants, 
and there supply the necessary quantity of nitrogen. He described the experiments — 
which led him to this conclusion, which were very elaborate, and were made on barley 
plants grown in non-nitrogenous soils, and in confined spaces supplied with air freed 
from ammonia. The following conclusions were deducible from the results of his 
experiments, viz—1. That the perfect development of barley can take place, under 
