274 Descriptiofi of a New Compensatijig Pendulum. 



17th, and Cornns florida on the 24th. An unusual depression of 

 temperature on the 4th of March, sinking the mercury to four 

 degrees below zero, destroyed nearly all the blossom buds of the 

 pear and the peach. Apples, and all the smaller fruits, were 

 abundant. The severe storms in December, which visited the 

 coast in the eastern states, were but slightly felt here. On the 

 15th, 22d, and 28th of December, we had falls of snow, accom- 

 panied with but litde wind, amounting in all to about a foot. 

 Thirty miles west of this place the ground has barely been cov- 

 ered with snow, to this time, the twentieth of January, while 

 E. and S. E. as we approach the mountain ranges, it has fallen 

 to a depth unprecedented for many years. The same great 

 abundance of snow seems also to have attended the storms in the 

 middle and eastern states. 



January 20, 1840. 



Art. IX. — Descriptio7i of a New Compensating Pendulum ; by 

 William Gwynn JoiNes, A. M. 



During the latter part of the past year, while engaged in some 

 interesting astronomical observations which required considerable 

 accuracy, it was indispensable to procure a time-keeper whose rate 

 would not be affected by the variations in the temperature of the 

 weather, to which all such machines, of ordinary construction, are 

 liable. The expensiveness of a chronometer which could be 

 relied upon for such a purpose, rendered a resort to some more 

 economical instrument desirable, if it could be depended upon. 

 The gridiron pendulum as well as the mercurial one, both of 

 which have been designed to effect this object, were found unsat- 

 isfactory ; the former from the difficulty of procuring an exact 

 adjustment of the different rods of which it is composed, so as to 

 produce the desired counterbalancing expansion and contraction, 

 and the mercurial pendulum proving upon experiment too sensi- 

 tive to be relied upon. Under these circumstances, I contrived a 

 simple arrangement for a pendulum, acting upon the principle of 

 the lever, which performed with so much accuracy that I have 

 been induced to present it to the notice of the readers of the 

 American Journal, believing it will not prove uninteresting to 

 those engaged in scientific investigations requiring great uni- 



