The New York herald., 1851-08-26

| described was repeated with an improved arrange
ment.
| Inside of the inverted bell, so as to cover tho
bore OF the neck Immediately over which il rested
e uss y, WIRE gauze was placed, supporting few
shun INN , oi eaded cotton About half inch
ABOVE the mouth of the bell, another disk or trav
| OF wire gauze was upheld by appropriate means
on winch there was put stratum of carded cotton
n s9ncientty copious, These preparations being COM
withstanding the enormous rise of Temperatures Thus
produced in the upper part Of the column of air Of
which lower portion occupied the bell glass so en-
tirey was this lower portion uninHusnced tina.
there not the least perceptible agitation pro-
duced among the most delicate hbres of the cot
ton.
II is admitted that, on reaching the rari6ed re-
gion where the atmosphere clouds appear, The
seauent condens iton of aqueous vapor will make
any body of air containing it warmer than il would
otherwise be, and from the lowest level above which
the heat is applied, there would be more or less
distur barce in conse9 of the greater buoyaney
Of the column warmed by the CONDENSATION OF va
por But this disturbance would, as conceive, be
much less abrupt and toIoibe than the Espan hypo-
thesis of storms requires
Even after the condensation OF aqueous yapor IS
effected the water which formed it viii remain
within the column, and still add TO It's weight, so
that the total weight will not be mlnished:
Moreover, by swelling upwards, as it naturally Will
DO, towards the regicn where there Is Ieass resist
ancc, it will become much taller as rarer, and
thus compensate by its greater height for the loss
Of specific gravity. la a none,astc mud, any supe-
riority of elevation in any portion expanded more
overflow of the excess; but in electric fuid, where
the summit must be rare as TO have scarcely any
susceptible weight 10 such active overilo can take
place as would be requisite to produce any V!oleas
exchange of position between the column thus
affected and the cylindera mass of the atmosphere
by which IL is surrounded.
LARGE REFLEcTIN6 TELESCOPE, BY j. SEYMOUR,
LATE PRINCIPAL OF THE ACADEMY, LENox, Mass.
There was large telescope presented for the ex-
animation of the American Association, which at
tracted the attention of the members Ii is OF the
reHactjpp kind The 4Ocal length Is sixteen fSet,
aperture nine and ha!f inches in the clear. The
tube is composed of thick Russia iron. painted ana
yarnished;, the parts being fastened together oy
brass bands The arrangement for observation is
that Of Hersehel and Lord Rosse the huder being
placed the left of that end of the instrument d
rected to the object viewed end the eyetuoe On the
right. The lower end Of the instrument, mas at
tached to it framework resting upon two piVotss
at the ends of horizontal axis In the centre or
this axis is socket upon vertical axis rising from
the centre of duodruped, which rests upon the
ground or the floor of the observatory, as the case
may be. The end Of the telescope directed TO the
object observed, is supported by two legs engtoen-
cd shortened at pleasure, by combination ot
cranks, cords and pulleys; the whole so contrived
as to allow of every necessary motion without any
crampng Of the parts.
This description refers to the instrument when
used in a portable form. By using, however dit-
ferent foot piece the vertical axis named above be-
comes polar axis. There can be attached 20 tne
lower end Of the instrument, dechnation and nour
circles and thus it possesses most OF the practicaI
advanta ges of an equatorial instrument. stars can
then be examined in sunlight or by night, and re-
tain the same relative position in the field OF the
telescope. . 49,
Ore of the essential peculiarties OF this instru-
ment is that the large specuium Is held In It's posi-
tion by an arrangement giving perfectly uniform
pressure to its whole surface that slight pressure
itsef being almost wholly counteracted by antago-
mist pressure After all, the main excellence or
the instrument hes in the great accuracy OF the
figure of the speculun, which, to say the least has
an extremely close approximation to the curve OF
the parabola The instrument has as yet been but
partially tested.