Equilibrium between Living and Dead Forces. 241 



latitude, they were much colder than those of Europe. This fact 

 which could not be satisfactorily explained by the astronomic the- 

 ory of climates, engaged the attention of many naturalists, and 

 among others, of Halley. According to that celebrated philoso- 

 pher, a comet had formerly struck the earth obliquely, and chang- 

 ed the position of itsfcxis of rotation. In consequence of that 

 event, the north pole, which had originally been very near to 

 Hudson's Bay, was changed to a more easterly position ; but the 

 countries which it abandoned had been so long a time, and so 

 deeply frozen, that evident vestiges still remain of its ancient po- 

 lar rigor. A long series of years would be required for the solar 

 action to impart to the northern parts of the new continent, the 

 climate of their present geographical position." 



Fortunately our knowledge of meteorology is now sufficiently 

 advanced to enable us to laugh at this crude explanation of a 

 change in the position of the terrestrial axis, resulting from the 

 concussion of a comet. 



RT> H- — On the Condition of Equilibrium between Living 

 a nd Dead Forces; by Robert Henry Fauntleroy, Civil 

 Engineer, New Harmony, Ind. 



ls of essential importance to practical mechanics to establish 



ftematically the relations between a moving or living force 



] a pressure or weight at rest, sometimes called a dead force. 



s °r example, it is frequently important to know the greatest 



. ei § ht vv hich may be placed on the head of a pile without caus- 



s u to sink deeper, the circumstances attending the driving 



ln g known. It is chiefly to facilitate the solution of problems 



ls nature that the following remarks are submitted. 



m °ng the mathematical works consulted on the subject, there 



several that allude to it under the title of vis viva, stating its 



e to be proportional to matter multiplied by the square of its 



Clt y; but there was found no expression for the exact meas- 



Ure of effect. 



A f p 



iew quotations showing how the subject is sometimes treat- 

 >**y not be out of place here. 



Jathematically speaking, there is no comparison between 

 Ve force and a dead one j however, repeated experience 



