166 G. W. Hough on Cataloguing and Charting Stars. 
with strong currents of water, the See agency of these 
currents would bear them rapidly a 
As it is, minute quantities come ts be surface with the ee . 
showing a very slow process of drainage. As an index of the 
location of oil-cavities this sign is not “yeliable ; for that whi 
issues may have been carried by the streamlets many miles 
along by descending currents, is not likely to wander so far 
before it issues, But the ‘show of oil” increases in value as a 
sign with the depth at which it is found, Especially is the find- 
ing of large quantities of imprisoned gas, though no oil may 
present, regarded as a good indication that there is oil near. 
Marietta, May 4th, 1864. 
Art. XIV.—Description of a new met vee fae oe and 
Charting Stars; by G. W. H 
THE progress of instrumental astronomy has been so rapid 
during the last half century, not only in the —_— of the 
th 
older instruments, but also in the invention of new methods of 
observation, ees at the present time, in certain pinaien of work, 
more observatio 8 can be made in one year than could formes 
have been sonas in five 
= = year — the application of electricity to, the record- 
in tronomical Observations was first suggested. This 
ane ciagene idea soon resulted in the construction of Chro- 
nographs by various persons, by which the instant of transit of 
a star was accurately recorded in a legible and permanen nt man- 
ner. Success in the recording of one ordinate of a star’s position 
would naturally suggest the possibility of fixing the other by 
the same agency. But with the exception of some experiments 
made by the late Prof. O. M. Mitchel for the recording of deeli- 
nations by electricity, this subject, so far as I know, has not been 
undertaken by any other astronomer. 
In the formation of catalogues of zone stars, astronomers have 
almost invariably used the gener yet in a fixed position, and, 
by means of a diaphragm or scale placed in the focus, deter 
mined the time of transit so difference of declination. In our 
method, the Telescope is moved in zenith ciasens, the amount 
of motion giving us the difference of declinatio: 
ecb aeeig of observing the —- of ane between 
two ects, magnifying by m nical means the angular 
ae acer say the "reese, ies to the late Prof, 0. M. Mitchel, 
? put it 
alia cnense tose ur bei 
fn account of which willbe dels 
