SCIENTIFIC NEWS. 379 



■ The bottom of the box is a wooden grating, the bars of Apparatus de- 

 which are Tery open ; and about three feet beneath it is a**^'^^'^*^ 

 vessel to receive the concentrated fluid. There it will 

 receive the first impression, of the open air, and be still 

 more concentrated. 



In the case we have noticed, when the air is not suffl, 

 ciently drying, it maybe heated bypassing it through a 

 furnace, the chimney of which widens to at least 1000 square 

 inches; and takes in fresh air by sufficient openings for the 

 purpose. This pipe should be divided into four others of 

 250 square inches each, communicating with the openings 

 at the bottom of the four sides of the box. 



After the description here given, it is obvious, that the 

 ventilator, turned by tlie raau, throws the air from be- 

 tween its wings to the circumference, and draws in fresh aic 

 at its centre, which air traverses the whole heap of twigs, 

 and consequently the fluid. If this be not sufficiently con- 

 centrated in one descent, it may be pumped up again, and 

 fiuft'ered to fall as often as is necessary. ..^ 



• Montgolfier attempted to do without the twigs, by form- 

 ing small jets of fluid in the box, the height of which he in- 

 creased : but this mode is not. economical with regard to ex- 

 pense of power. They n>igU,t be dispensed with, however, 

 by adopting the following contrivance. In the lower vessel, 

 that receives the fluid, place a wooden roller, turning on 

 its axis. At the top of the box, which in this case should 

 be long and narrow instead of square, place a similar roller, 

 with a winch affixed to it without. Over these two rollers 

 pass an endless band of cloth, and this, on turning the 

 winch, will raise the fluid, and expose it to the air on an 

 extensive surface. 



SCIEJ^TIFIC NEW^. 

 Wernerian Naturflf History Society* 



PiJT the meeting of this society, on the 16th of February, Valley of Pent- 

 Professor Jameson read a minerealoerical description of the ^^nd, near 

 ' '.' U, - ^^ % , r^ ,. Edinburgh. 



romantic and interesting valley of rentland, near bdm- 



bivgh. 



