166 Analysis of Scientific Books. 
From the general results of these experiments, it is inferred 
that the light (and probably the heat,) generated in electrical discharges, 
depends principally upon some properties or substances belonging to the 
ponderable matter through which it passes; but they prove likewise that 
space, where there is no appreciable quantity of this matter, is capable 
of exhibiting electrical phenomena; and, under this point of view, they 
are favourable to the idea of the phenomena of electricity being produced 
by highly subtile fluid or flaids, of which the particles are repulsive, with 
respect to each other, and attractive of the particles of other matter. On 
such an abstruse question, however, there can be no demonstrative evi- 
dence. 
This paper contains many valuable hints respecting the ex- 
istence of air in mercury, and the best means of obtaining a 
vacuum free from it, which seem of considerable importance in 
their relation to the construction of barometers. 
9. Croonian Lecture. On the Anatomical Structure of the Eye, 
illustrated by Microscopical Drawings, executed by F. Bauer, 
Esq. By Sir E. Home, Bart., V.P.R.S. 
The author first states, that he got Mr. Bauer to ascertain 
the structure of the marsupium by examination in the micro- 
scope, to determine how far it was muscular, and it proved to 
be, as Dr. Young long ago considered it, wholly membranous. 
He then had the different parts of the eye examined in the 
same way, and gives a description of their structure in the hu- 
man eye, and in that of the quadruped, and of the bird. The ci- 
liary processes are in the human eye about eighty in number, 
lying directly behind the iris ; these are membranous, and very 
vascular. In the interstices between these processes are bundles 
of muscular fibres, -%; of an inch in length, which have never 
before been described ; they pass from the capsule of the vitreous 
humour to the capsule of the lens ; anteriorly, they are uncon- 
nected with the ciliary processes, or iris. In the choroid coat 
lymphatic vessels are shewn in the drawings, never before met 
with. The disease of a living worm met with in India in the 
aqueous humour of the horse’s eye, is explained by these worms 
being found in the blood of the horse, and the vessels in the 
ciliary processes being large enough to drop them into the ante- 
rior chamber of the eye. The fibres of the lens have the ap- 
pearance of hairs, like those formed in spun glass. 
The situation of the marsupium in the bird’s eye, is shewn in 
the drawings, both in the eagle and the goose, and the difference 
of curvature at the bottom of the eye on its two sides is endea- 
voured to be represented as accurately as such subjects admit 
of; by the nicest measurement, that side next the beak was 
38; of aninch, the other side 5th. 
Six plates accompany this paper, admirably executed by 
Mr. Basire, from the accurate drawings of that unrivalled 
draughtsman, Mr. Bauer. 
