Description of a new Compensation Pendulum. 27 



first, that is, those points of contact do, by the weight of 

 the ball, yield to each other in a small degree, until they get 

 a broader bearing. 



The advantages of this pendulum are, 1st, That from its 

 simplicity it will never fail to have the desired effect. 2dly, 

 That no extraordinary care is requisite in executing it. 3dly, 

 That the compensation may be increased or diminished with 

 the greatest ease, without stopping the clock more than a 

 minute, by making fast one of the screws that keep the rods 

 together whilst the adjusting screw is removing, taking care 

 to release it again afterwards. And 4thly, That it can be 

 manufactured for less expense than any other compensation, 

 pendulum hitherto published. 



N.B. The compensation of this pendulum which I now 

 send to the Society of Arts is properly adjusted, at least very 

 near the truth. The holes for the adjusting screw are made 

 at such a distance from each other, that by removing the 

 screw one hole, it will produce an alteration in the goino-of 

 the clock about a quarter of a second per day with a change, 

 of thirty degrees of Fahrenheit's thermometer. 



SIR, 



Permit me to state to you the observations I have made 

 since my compensation-pendulum was laid before the So- 

 ciety. 



The regulator, with the hammered zinc bar, and bail of 

 forty-six pounds weight, was firmly fixed to a brick wall at 

 the top of my house. The adjustment of the length of the 

 bars, by means of a lamp, was repeated as before. There 

 was, however, an alteration necessary to be noticed ; the ball 

 of the pendulum rested on its lower extremity, instead o( 

 being suspended by its centre. I prefer this method, as 

 being less liable to error if the rods should be sooner affected 

 by heat or cold than the ball. The length of the zinc bar, 

 as ascertained by the lamp, was now found to be 20 inches 

 and a quarter. 



The clock was then set to mean time, and suffered to go 

 without alteration ; the result is exhibited in the following 

 table. 



ISOrJ. 



