^80 Mr Rumker’s determination of the Longitude of 
examine either the reactions of these different systems of volca- 
noes on one another, or the distance to which, by subterranean 
communications, they at the same moment shake the Earth^*.” 
Art. IX. — 'Observations of several Occidtations of Fixed Stars 
hy the Moon in 1818 and 1819, and (f the Solar Eclipse of 
the Bth May ISIS, made at La Valette in Malta. By Mr 
Charles Rumker. Contained in a Letter to Prof Jameson, 
IP HEN , on my return from the Mediterranean, I mention- 
ed to Captain Hey wood that it would give me great satisfaction 
if any benefit to astronomy could be derived from the observa^ 
tions which I had there an opportunity of making, he pointed 
out the Edinburgh Philosophical Journal, as the best medium 
by which any useful information might be introduced to general 
notice, and encouraged me to address to you the present paper. 
The principal object of this Journal being the promotion of 
science, I hope that the annexed astronomical observations will 
find a place in it. Occultations are a kind of observations, that 
receive their final value only by comparison with corresponding 
observations of the same stars. The present observations were 
made on the same spot where, in the year 1 780, the Grandmaster 
Rohan fitted out, in the palace of La Valette, an observatory for 
the Chevalier d’Angos, which was afterwards partly destroyed 
by a fire that consumed all the papers containing the observa- 
tions made by this astronomer, who, discouraged by his bad 
success, returned to France his native country. 
* The following is the series of phenomena which M. Humboldt supposes to 
have had the same origin : 
27th September 179(5. Eruption in the West India Islands. Volcano of Gua- 
daloupe. — November 1796. The volcano of Pasto begins to emit smoke. — 14th of 
December 1796. Destruction of Curaana. — 4th of February 1797. Destruction 
of Riobamba. — 30th of January 1811. Appearance of Sabrina Island, in the 
Azores. It increases particularly on the 15th of June 1811, — May 1811. Begin- 
ning of the earthquakes in the Island St Vincent, which lasted till May 1812 — 
16th of December 1811. Beginning of the commotions in the Valley of the Mis- 
sis! ppi and the Ohio, which lasted till 1813. — December 1811. Earthquake at 
Caraccas — 26th of March 1812. Destruction of Caraccas. Earthquakes which 
continued till 1813.— 30th April 1812. Eruption of the volcano at St Vincent’s; 
and the same day subterranean noises at Caraccas, and on the banks of the Apura. 
