Philosophical Transactions. 165 
darst not make his approach. The animal fell upon its knees to enable 
the horn to bear upou any object. It was quick in all its motions ; ate ra- 
venously all kinds of vegetables, appearing to have no selection. They 
fed it on branches of the willow. It possessed little or no memory, dunged 
in one place, and, if not prevented, ate the dung, or spread it over the 
sides of the wall. Three years’ confinement made no alteration in its 
labifs, 
_ The account in the Bible of an unicorn not to be tamed, mentioned 
by Job, bears so great an affinity to this animal, that there is much reason 
to believe that it is the same, more especially, as no other animal has ever 
been described so devoid of intellect. In that age, the short horn might 
readily be overlooked, as it cannot be considered as an offensive weapon, 
and thesmoothness of the animal’s skin would give a greater resemblance 
to the horse than to any other animal. 
6. Extract of a Letter from Capt. Basil Hall, R.N., F.R.S., to 
W. H. Wollaston, M.D., V.P-R.S., containing Observations of 
a Comet seen at Valparaiso. 
7. Elements of'the above Comet. By J . Brinkley, D.D.,F.R.S., &c. 
This comet was in sight for thirty-three days, but Capt. Hall, 
being in the interior of the country when it first appeared, made 
no accurate observations till the 8th of April; it was then dis- 
tant nearly 1.41 from the earth, the sun’s distance from the 
earth being =1. On the 3d of May, when last seen, its dis- 
tance was =2,.64. This comet is interesting to astronomers 
from its small perihelion distance, and from the probability that 
it is the same that was observed in 1593, which agrees with 
this in its small perihelion distance, and great inclination. 
8. On the Electric Phenomena exhibited in Vacuo. By Sir 
Humphry Davy, Bart., P.R.S. 
Is electricity a subtile fluid, or are its effects merely the 
exhibition of the attractive powers of the particles of bodies ? 
Are heat and light elements of electricity, or mere effects of its 
action? Is magnetism identical with electricity, or an inde- 
pendent agent, put into motion or activity by electricity ? 
Though these abstruse and difficult questions exceed our present 
means of solution, it appeared to Sir Humphry an object of 
considerable moment, and intimately connected with them, to 
determine the relations of electricity to space as nearly void of 
matter as itcan be made upon the surface of the earth ; his 
experiments on these subjects are detailed in this paper. 
The most perfect mercurial vacuum that could be procured 
was permeable to, and rendered luminous by, electricity ; when 
the tube was very hot the light was green and dense; as the 
temperature diminished it became less vivid, and at — 20° was 
scarcely perceptible, except in avery dark place. The ingress 
of very small portions of air rendered the light blue and purple, 
and increased the conducting power of the medium. In a 
vacuum above fused tin, the phenomena were nearly the same. 
M 2 
