74 Progress of Invention. 



that may be considered absolutely uniform. In this apparatus, 

 the rods and balls of the centrifugal governor are replaced by 

 oblong triangular thin plates of metal, constituting vanes, which are 

 hinged by their vertices to the revolving upright spindle, and* move 

 in the same vertical plane. They are prevented from flying out to 

 their full extent by slight increments in the velocity of rotation, by 

 spiral springs which, being fixed to their centres of gravity, are the 

 causes of no disturbing influence. When the velocity is that which 

 is required, the resistance offered by these vanes, as they hang down 

 along the revolving spindle suffices to absorb the excess of motion, 

 so as to prevent the velocity from becoming accelerated ; but the 

 slightest increase of velocity causes them to fly asunder by means 

 of centrifugal force, and to an extent which depends on the increase 

 of velocity. As the distance of the vanes, and especially of their 

 broader portions, from the axis of motion is increased, the resistance 

 they experience from air, which has also been augmented by the 

 increased velocity, is increased ; and hence eqtiilibrium is soon 

 established between the disturbing and controlling agents. The 

 velocity which this apparatus will permit is entirely under control ; 

 since it depends on the size of the vanes, the quantity of matter 

 they contain, and the relative power of the springs. When one 

 velocity is to be changed into a very different one from that pre- 

 viously required, it is necessary to change the springs ; but when 

 the desired alteration is inconsiderable, movable metallic masses, 

 are merely slipped up and down along the vanes by means of screws, 

 so as to alter their distance from the axis of motion, when the 

 vanes fly apart. This affords an easy mode of regulation to any 

 velocity desired. So accurate is the adjustment of velocity 

 obtained by this contrivance that power may be taken for any 

 required purpose from a clock regulated by it, without^ disturbing 

 the accuracy of the rate of going* 



A New and extremely Powerful Electrical Apparatus. — The 

 production of electrical currents by means of magnetism, or electro- 

 magnetism, is used by Mr. Wild of Manchester for the obtaining 

 of enormous quantities of electricity, by means of a contrivance 

 which, considering its vast power, is neither complicated nor 

 expensive. He was led to the invention of this apparatus, 

 by discovering a mode of utilizing the important fact ascer- 

 tained a considerable time since by M. Seguin, that a very large 

 quantity of electricity may be developed in an electro-magnet by 

 a permanent magnet of very small power. As an electro-magnet 

 possesses all the properties of a permanent magnet, the effect thus 

 obtained can, of course, be multiplied to any extent, by successive 

 elements added to the apparatus ; but it was found that the 

 principle repeated three times, that is by the use of three elements ; 

 ■afforded quantities of electricity quite as large as could be desired. 

 Each element of this apparatus consists of one or more, either 

 permanent or electro-horse-shoe magnets, and a kind of cylinder 

 within which revolves an armature. The cylinder, or rather the 

 cylindroid, which has four flattened sides, constituting a kind of 

 quadrangular prism, having rounded corners parallel to its length, 



