Miscellaneous Intelligence. A437 
VIII. The head of this department could present, through the Libra- 
ry Committee, an annual report, on the geographical explorations by 
our own and foreign Governments, or ay oo o far as their 
D ee 
teresting and important geographical ‘iste or publications for the year. 
Among the duties which would belong to this department would 
be that of calling attention to i lon demanding examination, or locali- 
lies needing exploration. Also, it would be able to furnish the prelimi 
nary information for such explorations, or to indicate the sources whence 
it could be derived. 
e Composition and Figuring oY - Specula for Reflecting 
n 
ie a ih (Proc. Brit. Assoc., 1853 ; ee 8.)-—-Mr. Souuir 
ommenced by stating that he had given ‘is pe to this subject for 
years, and that he was more than ever convinced of its importance by 
once well and carefully made, were far less apt to deteriorate than re- 
one In order to be intelligible to the section, it was necessary for 
him to go over some ground familiar to the public, since the researches 
of Lod Rosse, Mr. Lassell, and Mr. Nasmyth. He stated that he con- 
sidered it to be a matter of prime eR as a the copper and tin 
should be used in exact atomic proportio , following the num- 
_ given by Berzelius, used the following ectenita :——copper 32 ; 
n 17:4. Lord Rosse’s are, co pper oes tin 14:9. s the metal when 
proportions e found on trial best :—copper 32; tin 15°5; nickel 2. 
e also found she introduction of a very small quantity of arsenic useful 
in preventing the oxydation of the tin when melti ¥ 
M ssell he also found excellent; but he was against the use of 
fluxes, as most injurious. The author passed over the casting and 
grinding with very slight notice ; but dwelt on the composition and 
figuring of the polisher as of great importanc ‘he composition as 
cular grooves,——and not sie parallel and cross grooves, as use 
Rosse and Mr. Lassell. These concentric grooves he crossed by radial 
grooves, widening as they receded from the centre, so as to be bounde 
by curved outlines. By giving proper form and dimensions to these 
curves the nene form could be most accurately given to the spec- 
trum in the process of polishing. The form of the curved outlines of 
these radial Aissaient he found should be parabolic. He concluded by 
stating the importance of st having the speculum too thin, and of using 
proper dale in mounting and supporting it, to avoid any chance 
aL 
CORESBY aiid that having been in another section he had not 
ee" the early part of the communication of Mr. Sollitt; but he rather 
