382 Royal Institution of Great Britain. 
Report alluded to above. 
At a meeting of the Committee of the Astronomical Society 
for reporting on the propriety of purchasing specimens of 
M. Guinand’s glass for further trials, held March 17, 1823, 
The telescope constructed by Mr. Tulley was produced and 
examined, and his letter, and that of Mr. Dollond read, as 
also such parts of a correspondence between the Foreign Se- 
cretary and M. Reynier, as appeared necessary. 
It was then resolved, That it appears to your Committee that 
M. Guinand has not answered in a satisfactory manner to 
the inquiry put to him through M. Reynier, whether he will 
engage to furnish the London artists at a reasonable price, with 
flint glass fit for their purposes, inasmuch as he holds out no 
assurance of a regular supply, and has actually but a very li- 
mited quantity of his am to dispose of, and that principally 
in discs not exceeding four inches in diameter ; and your Com- 
mittee conceive that no degree of excellence in individual 
specimens would authorize them to recommend their purchase 
by the Society, unless supported by such assurances of con- 
stant supply, as would render it a matter of public interest. — 
(Signed) Davies Griperr. 
J. F. W. Herscuet. 
April 11, 1823, Wo. Pearson. 
ROYAL INSTITUTION OF GREAT BRITAIN. 
April 28.—A paper on the porphyry of Christiania was read 
by Mr.S. Solly, in the Lecture-room, and illustrated by a series 
of engravings and of geological specimens from Prof. Esmark. 
‘Instruments, drawings and diagrams, were exhibited and ex- 
plained in the Library by Mr. Jopling, in illustration of his 
septenary system of lines produced by double continuous mo- 
tion. A series of types, stereotype plates, and impressions of 
type-music-printing from the office of Mr. Clowes, were laid 
upon the table. The advantages of this mode were stated to 
be accuracy in composition and clearness of the page. 
May 5.—The relations of sulphuric acid to hydro-carbon, 
as illustrated by the late researches into the nature of the sul- 
phovinic and sulpho-naphthalic acids were detailed by Mr. Fa- 
raday, in an experimental discourse from the lecture-table, and 
the striking points discovered by Mr. Hennell and himself 
explained and enforced. Mr. Perkins’s specimens of patterns 
produced by eccentric-lathe-turning, and also a pair of his 
steel plates and rollers for bank-note engraving, were laid on 
the library table. 
May 12.—Lieut. Drummond’s beautiful and intense Station 
Light 
