MANUFACTURE OF GLASS FOR OPTICAL PURPOSES. 
3 
gathered^ that though all were to do what they could in every way for the general 
good of the cause in which they were jointly engaged, yet a distinction in the 
duties of each existed. It was my business to investigate particularly the 
chemical part of the inquiry ; Mr. Dollond was to work and try the glass, and 
ascertain practically its good or bad qualities ; whilst Mr. Herschel was to 
examine its physical properties, reason respecting their influence and utility, 
and make his competent mind bear upon every part of the inquiry. 
The experimental glass-house was erected on a part of the premises of Messrs. 
Green and Pellatt, at the Falcon Glass-works ; whilst my duties as Director 
of the Laboratory of the Royal Institution, required my presence almost con- 
stantly at the latter place, nearly three miles from the former. As I found it 
impossible under these circumstances to make the numerous experiments and 
pay that close attention which appeared essentially necessary to produce any 
degree of success, the President and Council of the Royal Society applied to 
the President and Managers of the Royal Institution, for leave to erect on their 
premises an experimental room, with a furnace, for the purpose of continuing 
the investigation. They were guided in this by the desire which the Royal 
Institution has always evinced to assist in the advancement of science ; and the 
readiness with which the application was granted, showed that no mistaken 
notion had been formed in this respect. As a member of both bodies, I felt 
much anxiety that the investigation should be successful. A room and furnaces 
were built at the Royal Institution in September 1827, and an assistant was 
engaged, Sergeant Anderson of the Royal Artillery, whose steady and intelli- 
gent care has been of the greatest service to me in the experiments that have 
been proceeding constantly from that time to the present. At first, the inquiry 
was pursued principally as related to flint and crown glass ; but in September 
1828 it was directed exclusively to the preparation and perfection of peculiar 
heavy and fusible glasses, from which time to the present continual progress 
has been made. 
I have thought it right to give this brief explanatory statement of the manner 
in which it has happened to become my duty, on the present occasion, to give an 
account of what has been done in the improvement of glass for optical purposes 
by the Committee of the Royal Society, working at the Royal Institution. I 
would willingly have deferred this account until the inquiry were more com- 
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