New Orleans daily crescent. [volume] ([New Orleans, La.]) 1851-1866, 1856-03-07
~ LyccIEI,l Lectures.

The lecture of Professor Gould last evening upon
the subjectof astronomical instruments was highly
interesting to persons Of mechanical turn of mind,
wellas to those who curious in regard tOthe
wonderful machinery by means Of which the great
problems of astronomy are solved. The inclemency
Of the weather, combined with other causes, pre-
vented the Hall from being uncomtortably crowded.
In regard to astronomical Instruments the lecturer
stated that it was not possible they should be perfect
either in construction operation, and he specified
various causes which must always exist to render the
attainment of this object impossible. He then pro-
coed to explain, in lucid and satisfactory manner,
the use and application of the Meridian Circle-the
most important instrument, practically, to the abors
of the modern astronomer
We are chiefly indebted, the Professor stated to
Besse and Shruber for our greatest astronomical
instruments, and twas the former who first demon
stratcd the physiological difference between observers
Of equal powers of perception-onc to instance
invariably noting the transit of star across the tele
scopic line fractional part of second sooner
than another.
4 Among the systems that had fallen into disuse was
that of building high towers for astronomical obserya
ton. An elevated position had disadvantages, among
them a clear and rarifed atmospheric medium, but
these oerbalanced by the necessity of that stab
lily of foundation whelcan only be obtained byprox
unity to the earths surface Therefore, observatores
are now generally constructed upon rising ground but
with view rather to irmness of foundation than to
elevation.
The Professor then proceeded to consider the new
method of observation by magnetic telegraph--an
American discovery mainly attributable to Professor
Bache, of the Coast Survey. The old method of de-
tern1ining the differences Of longtude-by transport
ing thermometers from one place to another-could
not be depended upon for accuracy, chronometers
are liable to variation, particularly under such crcum
stances But this difficulty obviated by the dis
covery of the Magnetic Clock, by whose ticngs the
notation of the transit Of star can be simultaneously
recorded at the place Of observation and thousand
miles away 1t also has the advantage of accuracy
a1mostsabsoute PROFESSIONALISM of requiring a much
less degree of labor the part of the observer With
it the pupil may perform a,task which, under the old
method, would require all the and skill Of the
master. In Europe this is known as the American
method and has been used for determining the exact
longitude of the principal cities of European countries
not however, with satisfactory results as in this
country The principle and operation of this instru
mcnt were explained by diagrams.
The lecturer briefly alluded to the Heliometrc-the
most difficult Of construction and delicate in opera
ton among all astronomical instruments. Mr.. Spen-
GER of Canestota N.Y. the excellence of whose tee-
scopes had driven competition from the field, had
been commissioned to produce hcliometre Of extra
ordinary capacity for the New Boston Observatory
and would shortly proceed to Europe on tour Of in
vestigation.
| The Professor closed with few eloquent and ap
propriate remarks upon the general nature Of his
subject and announced that his next lecture woult
take place on Wednesday evening next.