180 PROCEEDINGS OF SOCIETIES. 
of destroying them, their number is increased. We must not 
omit to mention a very fine variety of injected preparations, by 
A. B. Stirling, Esq., of Edinburgh, and exhibited by Mr. Craggs. 
One remark more, and that is with respect to the instrument ex- 
hibited by Mr. J. Martin, a working mechanician, of South 
Shields, who, having turned his attention to microscopes, stands 
perhaps alone in the district as an amateur manufacturer of 
microscopes, which approach, either in point of finish or useful- 
ness, those produced by many of the most practical manufac- 
turers. The exhibition was, altogether, of the most interesting 
description, the “ wonders of the microscope ”’ being largely added 
to by the specimens presented for inspection. Between the parts 
of the concert, 
Mr. T. P. Barkas proceeded to give some “ Observations on 
the Microscope as an Educational Agent and Instrument of 
Scientific Research,” of which the following is an abstract :— 
“The eye saw that which it brought with it, the power of seeing,” 
was true, not only in relation to the esthetical aspect, but also to 
the optical. sthetically and optically, no two persons saw ex- 
ternal objects alike. The optical, however, more closely approxi- 
mated than the psychological; yet in relation to the merely 
optical, “the eye only saw that which it brought with it, the 
power of seeing,” and without the aid of our telescopes and micro- 
scopes, worlds, systems, and existences with which we were now 
generally familiar, and which were far more varied and numerous 
than those within reach of our unaided vision, would be entirely 
unknown to us. Mr. Barkas then proceeded to explain the 
leading properties of light, and showed that the difficulties in 
relation to the manufacture of optical instruments which Sir 
Isaac Newton, Wollaston, and others thought insuperable, 
namely, those of achromatic and spherical aberration, had been 
almost if not entirely overcome; and we had now microscopes 
nearly as free from imperfection as was the human eye itself. 
The eye, however, displayed that peculiar characteristic of all the 
Almighty’s works—it exhibited the largest results with the 
smallest means, and did, by a modification of one lens, what eight 
lenses were required to accomplish in our favourite optical instru- 
ment. He then proceeded to trace the history of the microscope, 
commencing with the Assyrian lens, discovered by Layard, three 
thousand years old, from the date of which till 1590 little progress 
was made in microscopical manufacture. No microscope really 
worthy of the name was made until 1660, and even in 1821 no 
microscope was achromatic. Since that period, Brewster, Airy, 
Coddington, and others, aided by the practical experience of 
Rosse, Powell, and Leland, Smith and Beck, and others, had 
brought the microscope to perfection. Mr. Barkas then drew 
the attention of the audience to several of the specimens which 
had been exhibited on the tables that evening, more especially 
the objects selected from the vegetable world, the first in order 
