l, which,
in the hands of modern chemists, has become the foundation of our
splendid aniline dyes. But he swerved incessantly from chemistry into
physics; and in 1826 we find him engaged in investigating the limits
of vaporization, and showing, by exceedingly strong and apparently
conclusive arguments, that even in the case of mercury such a limit
exists; much more he conceived it to be certain that our atmosphere does
not contain the vapour of the fixed constituents of the earth's crust.
This question, I may say, is likely to remain an open one. Dr. Rankine,
for example, has lately drawn attention to the odour of certain metals;
whence comes this odour, if it be not from the vapour of the metal?

In 1825 Faraday became a member of a committee, to which Sir John
Herschel and Mr. Dollond also belonged, appointed by the Royal Society
to examine, and if possible improve, the manufacture of glass for
optical purposes. Their experiments continued till 1829, when the
account of them constituted the subject of a 'Bakerian Lecture.' This
lectureship, founded in 1774 by Henry Baker, Esq., of the Strand,
London, provides that every year a lecture shall be given before the
Royal Society, the sum of four pounds being paid to the lecturer. The
Bakerian Lecture, however, has long since passed from the region of
pay to that of honour, papers of mark only being chosen for it by
the council of the Society. Faraday's first Bakerian Lecture, 'On the
Manufacture of Glass for Optical Purposes,' was delivered at the
close of 1829. It is a most elaborate and conscientious description of
processes, precautions, and results: the details were so exact and
so minute, and the paper consequently so long, that three successive
sittings of the Royal Society were taken up by the delivery of the
lecture.[3] This glass did not turn out to be of important practical
use, but it happened afterwards to be the foundation of two of Faraday's
greatest discoveries.[4]

The experiments here referred to were commenced at the Falcon Glass
Works, on the premises of Messrs. Green and Pellatt, but Faraday could
not conveniently attend to them there. In 1827, therefore, a furnace was
erected in the yard of the Royal Institution; and it was at this time,
and with a view of assisting him at the furnace, that Faraday engaged
Sergeant Anderson, of the Royal Artillery, the respectable, truthful,
and altogether trustworthy man whose appearance here is so fresh in our
memo