Miscellanies, 



209 



Ferruginous concretions are not uncommon, as in the columnar and 

 pea-shaped argillaceous iron ores, in the bog ore, the oetite 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. — Senior Editor. 



15. Spark Extinguisher. 



Keerie, N. H., July 19, 1841. 

 To the Editors of the American Journal of Science and Arts. 

 Gentlemen — Annexed is a drawing of an apparatus, which I have 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 

 if it communicates with the smoke chest. 



B, the cylinder in which the fan revolves. 

 A, the chimney of 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- 

 munication be made between the chim- 

 ney and the opening C, by means of a 

 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 in the drawing show the position of this, 

 pipe in the chimney ; 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 h in 

 the figure ; the doors at the top of the funnel F may be raised while 

 raising the steam. 



Vol. xLii, No. 1,— Oct.-Dec. 1841. 27 



