302 Astronom. Society.— Royal: Geolog. Society of Cornwall. 
the products proved equal, if not superior, to the smaller products 
of the laboratory. , f 
The most valuable alloys formed with steel, were those formed 
with silver, platinum, rhodium, iridium, osmium and palladium, 
in the proportion of one hundredth of these metals, except silver, 
with which steel will combine only one five hundredth part ; 
when more is fused, the metals form only a mechanical mixture. 
The alloys are applicable to every purpose for which good steet 
is employed, but the cost must ever prevent their general appli- 
cation. . a 
Platinum and rhodium combine with steel in every proportion, 
forming with some of the higher proportions beautiful compounds, 
the colour favourable for metallic mirrors, and not subject to 
tarnish in the air, 
ASTRONOMICAL SOCIETY OF LONDON. 
April 12,—Various papers were read at this meeting. The 
first was a communication from Mr. Lambert, giving au account 
of the result of his calculations relative to the longitude and 
latitude of the Capitol, in the City of Washington. The second 
was a list of observations of the planets, during the period of 
their respective oppositions, in the preceding year: with com- 
putations of their longitudes and latitudes, with a view to cor- 
rect the errors of the tables, from Mr. Groombridge. The third 
consisted of a variety of communications from Major-General 
Sir Thomas Brisbane: some relating to the determination of the 
position of several places, others detailing some observations on 
the magnetic needle; and all of them of considerable interest : 
but the most remarkable (because the most singular) was his ae- 
count of an occultation of the planet Mercury by the Moon, 
which was observed aé sea; and he adds that, at the emersion, 
the planet appeared to have retrograded 2’ on the disc of the 
Moon. The fourth was a communication from M. Littrow re- 
specting the practicability of making use of the pole star, at any 
time that it is visible, for the purpose of determining the latitude 
of the place of observation: with a collection of useful tables. 
The next meeting of the Society will be on Friday, May 10th. 
ROYAL GEOLOGICAL SOCIETY OF CORNWALL. 
Since the last Report the following papers have been read : 
On the Mineral Productions and Geology of the Parish of St. 
Just. By Joseph Care, Esq. F.R.S. M.R.I.A. Member of the 
Society. 
On some Adyantages which Cornwall possesses for the Sin 
o 
