210 [Mr. G. F. Rodwell on the Effects 



ing furnaces with air by this means had been inventf .'. and was 

 -ively used. Although a nevr invention, it was at this time 

 (1655 used in Germany and Italy, and in more than a hundred 

 places in Dauphiny. 



T/.: machine described t is consisted : hannel or 



trough in water was caused to rlow in a horizontal direc- 



tion : from the ttom of the trough two vertical tul oded, 



remity of each passed into a wooden tab fur- 

 nished with an outlet foi water, and a tube near its upper part 

 for the exir of air : within each tub. m '. immediately beneath 

 the loi . : "::. smity of the rube which entered it. a large c: 

 stone was placed in ::..e: tc break the fall of the water; the 

 upper extremity :: each tube near its juncture with :_e trough 

 was enlarged and :f a conical form, but in some forms if the 

 machine the tubes had holes pierced in their circumference : : i 

 the purpose of giving frea access to the air. Francois mentions 

 that Kircher assured him that he had sri-n more than for* :: 

 these machines with tubes in an inclined position. 



Irr the first volume of the Philosophical Transactions 1665) 

 there is :. short lescription* accompanied jy a figure :: ■ 

 water-blowing machine used in Italy. A stream .: watei is 

 re resented flowing through a large, vertical^ i octangular tube, 

 midway between th - and bottom :: which there is a pipe 

 for conveying the ilast :: a furnace: but the machine is evi- 

 dently wrongly figured and lescribedj for it is impossible that a 

 current of air could be produced by such an arrangement. 



In the 43rd volume of the Philosophical Transactions there is 

 a paper (read March 1711 15 by a Mr. James Stirling, 

 entitled u A Description of a Machine to blow fire by the fall of 

 Water/' This machine was a modified form :: that described 

 by Franc is; :: consisted .: a large funnel a feet high, from 

 the apex of which proceeded a tube from 14 to 16 feet long; 

 the . ret extremity of the tube passed intc :. vessel 5| feet dia- 

 meter, provided with a tube foi :Le exit of the air- carried down, 

 and also with an mtlet foi watei ; four orifices were made in the 

 circumference of the tube just bene?.:r. its juncture with the 

 neL 



From the met rfthis paper having been read before the Royal 

 S aety, it would appear that the trompe was but little known 

 in England even a hundred years after its invention; but that 

 this was the case is scarcely to be wondered at when we remem- 

 ber that such a machine can only be used with advantage in 



* Extra.:- letter raitten from Venice hy the learned D 



rPo| " Hie Reverend I'.-r.r. :: R.rpon. Doctor ■- o.:"- ' v : ..or: ?, con- 

 cerning the Mines of Mercury in Friuli; and a way of producing wind by 

 a fall of water. 



