88 
FIRST REPORT- 1831. 
one eighth of the diameter of the planet, when it may be again 
detected as a bright disc, and remains so till it passes entirely 
off the face of the planet. 
“ This anomaly I have witnessed three or, I believe, four times, 
and the last on Saturday fortnight, when the satellite itself in¬ 
stead of being invisible, except near the limbs, was perfectly 
visible as a black disc, and with its attendant shadow, was 
distinctly seen with the five-feet equatorial. The point to be 
settled is,—why should this fact be presented sometimes and 
not always ? 
“ The approaching disappearance of Saturn’s Ring, and even 
its present situation, will be very advantageous for obtaining 
a knowledge of the various phaenomena of the Satellites, and of 
the actual figure of the planet. Of the former we know next 
to nothing ; of the latter, but little that is satisfactory. Sir 
William Herschel’s observations of the planet’s figure are en¬ 
tirely at variance with mine. 
“ If Lord Oxmantown, or any person possessing a large 
Reflector, would turn it every fine night on the Georgium 
Sidus, it would be well; for although Sir William Herschel 
expressed to me orally his doubts as to the accuracy of his 
observations, which assigned to that planet two rings perpen¬ 
dicular to each other, still I know not if this suspicion of his has 
ever been promulgated. One Satellite has certainly been seen 
with my Achromatic, and one also by Mr. Herschel, myself, and 
Struve with the twenty-feet Reflector. Laplace doubted the 
existence of more than two. If the others are not greatly more 
faint than the one I have seen, Lord Oxmantown will certainly 
detect them instantly with the immense quantity of light afforded 
by his Reflector.” 
SATURDAY EVENING. 
Dr. Daubeny read an account of Experiments on the com¬ 
bustion of Coal Gas performed at York, by the Rev.W. Taylor, 
from which it appeared that by regulating the quantity and mode 
of admission of the atmospheric air to the flame of a common 
Argand gas burner, the quantity of light might be much in¬ 
creased without increased expenditure of gas, while the colour 
of the light so produced varied according to circumstances. 
He referred the effects to the principle laid down by Sir H. 
Davy as to the luminosity of flame depending on the amount of 
solid matter maintained in a state of ignition at any given time. 
The Rev. Wm. Vernon Harcouiit showed a Lamp con¬ 
structed upon a new principle , and explained the principle and 
