• AMERICAN INSTITUTE. 4*19 



is capable of conveying sound, and by suitable devices the defects of the 

 ear may be overcome, and a language may be devised for those afflicted 

 with the worst forms of deafness. The undulations convoyed by the pho- 

 nophorus might thus be made perceptible to the totally deaf of our 

 Asylums, 



Mr. Garvey called attention to a fan-blower, or rather screw-blower, for 

 creating an artificial blast. The peculiarity of the screw is that the blades 

 are so carved as to prevent the development of centrifugal force in the cur- 

 rent of air, consequently the whole force is expended in driving a column 

 of air along the sieve, pipes, &c., to the place where the blast is required. 

 It works well, and occupies but little space. 



Mr. Johnson had also examined the blower alluded to, and admired it as 

 a very efficient apparatus though by no means the best he was acquainted 

 with. There is one in use at the Northern Foundery, in Jersey City, which 

 he considered the best he had ever seen, for all the force impressed on the 

 fans is communicated to the air, which cannot escape in any direction but 

 that of the blast pipe. 



Professor Hedriek stated that he had examined an axle-box for rail-cars, 

 which was fitted with friction rollers in an ingenious manner. In theory, 

 at least, the friction of the axle must be reduced to almost nothing by this 

 apparatus. Instead of slipping along the sides of a hole, the axle rolled 

 upon hardened steel rollers, which were loose in the .box, but were pre- 

 vented rubbing one against another by small rollers pivoted between them. 

 Such an arrangement can be applied either to rolling axles or to the shaft- 

 ing of machinery; and it is indifi"crent which shall revolve — the shaft 

 or the box. 



Mr. Garvey considered that, if the box rotated, the whole weight of the 

 shaft would have to be lifted through some small distance as each roller 

 passed under it, and that there would, consequently, be a destructive 

 vibration caused by the alternate rising and falling of the shaft, in addition 

 to a very considerable waste of power or enhancement of friction. On the 

 other hand, if the shaft rotated, it would be either directly on the top of 

 one roller or between two. In the first case it would wedge that one roller 

 between the two smaller rollers adjoining it, and so increase the friction 

 enormously ; or, in the other case, would wedge two of the rollers apart, 

 and so increase the friction far beyond wliat theoretical reasoning would in- 

 dicate. In any case, the rollers however hard they may be, would depart 

 from the true cylindrical shape while under pressure and there would be a 

 loss of power, which the inventor has not taken into account, in constantly 

 altering the shape of the rollers, however slight the alteration may be. In 

 fact there is no such thing as absolute rigidity in nature. When a force is 

 impressed upon any material body, it will produce an effect in the direction 

 of its action, and which will be determined in amount by the relation be- 

 tween the impressed force and the resistance which it meets. Unless, 

 therefore, the resistance be infinite, there must be some resultant. 



Professor Hedriek. — In my remarks I have taken into account the 



