136 Electricity in Machinery. 



horizontal band at the moment the narrow one was slipped from 

 the motor wheel upon the free pulley, the part of it connecting 

 the upper part of the drums was observed to relax, while that 

 connecting their lower surfaces, from being curved downwards 

 by its weights became proportionally tense. In the first case, the 

 upper part of the band was made tense by the great amount of 

 friction in the machinery which it had to overcome, and of course, 

 the friction of the band upon the drums was increased in the 

 same ratio. But when the free pulley only was turned, the fric- 

 tion to be overcome, and consequently that of the bands, was 

 much diminished ; and this increased amount of friction of the 

 bands upon the drums in the first case, is to be referred to as the 

 exciting cause of the electricity. 



From this statement you will observe that there was no friction 

 of the bands upon each other as is mentioned in the article referred 

 to above, since the horizontal bands were parallel and the vertical 

 ones eight inches apart at their nearest approximation. In another 

 part of the manufactory, however, two portions of a band were 

 observed which were crossing and rubbing upon each other, but 

 their friction was attended with no observable electrical eifects. 

 At this time however the band was passing around a free pulley j 

 I was therefore led to inquire as to its electrical state during the 

 motion of its machinery, and ascertained that its attractive power 

 for cotton, &c. at such times was as great as in that of the bands 

 already spoken of. 



Although these facts do not authorize us to dispute those in 



Mr. article, yet they naturally suggest the question whether 



the electricity in that case was not excited by the friction of the 

 band upon the wheels rather than upon each other, and if so, 

 whether the apparent difference between the bands below their 

 junction and above was not in reality caused by the application 

 of the jar in the one case to a tense, and in the other to a relaxed 

 portion of the band. 



Not being intimately acquainted with the action of electrical 

 apparatus in different circumstances, I am unable to say whether 

 increased pressure of the whole flap of the common machine upon 

 the cylinder would materially increase the amount of electricity 

 developed, but from the above facts, as well as the nature of the 

 case, I should suppose it would, and if so, the circumstance prop- 

 erly attended to in the construction of electrical machines, would 

 render them, cccteris paribus, much more powerful. 



