munication be made between the chim- 
ney and the opening C, by means ofa ~ 
erruginous concretions are not uncommon, as in the columnar and 
pea-shaped argillaceous iron ores, in the bog ore, the ctite or eagle 
stone, and the hollow balls resembling bomb-shells; but for the form 
of the latter, and for the tubular structure now under consideration, it 
is not, perhaps, easy to offer a reasonable solution. 
There cannot, however, be a doubt that the iron has been brought in 
by water, and that the form which the concretion assumed has been 
determined by extraneous causes.—Sentor Enrror. 
15. Spark capcentsiih 
e, N. H., July 19, 1841.. 
To the Editors of the American Journal ~ panei and Arts 
-Mimilonsu-=- Avpoged is a drawing of an apparatus, which I “ain tried 
on a small scale, for destroying the smoke and sparks of locomotive en- 
gines, and it operates effectually. It 
consists of a revolving fan, operating in 
a cylinder on the top of the chimney, or 
it may be placed in any other situation 
fit Sieh Be 
B, hus i: L Fig E> ee 1 
A, the. wits oo the engine. When 
the fan is in motion, there is a rush of 
air through the apertures, C, into the 
cylinder, from whence it is driven 
through the funnel E. Now if a com- 
funnel F, the operation will be mani- 
fest ; all the smoke and sparks will be 
drawn out of the chimney at D, through 
the funnel F, into the fan cylinder, from 
whence the pipe E may conduct them on the ground or to the fire; the 
wings of my fan are semi- cylindrical, with the concave side to the air. 
This form will throw off more air, and cause a stronger draught through 
C, which may be regulated by the velocity of the fan. The fan may 
be driven by the steam after it passes the piston, by placing a small 
float wheel at the top of the eduction pipe ; this pipe may be enlarged 
at the top so that the passage may not be diminished when the wheel 
is | placed there ; the dotted lines inthe drawing show the position of this 
pipe in the famndy’: : the wheel is placed in the large part g, and pro- 
pels the fan by means of a gear at the top of its shaft, shown at / in 
the figure ; the doors at the top of the funnel F may be raised whi while 
: ‘the steam. 
Vol. xn, No. 1.—Oct.-Dee. 1841. 27 
