AN ESSAY 



ON 



PROBABILITIES. 



CHAPTER I. 



ON THE NOTION OP PROBABILITY AND ITS MEASURE- 

 MENT ; ON THE PROVINCE OP MATHEMATICS WITH 

 REGARD TO IT, AND REPLY TO OBJECTIONS. 



WHEN the speculators of a former day were busily 

 employed in constructing celestial tables for the use of 

 prophets, or investigating the qualities of bodies for 

 the manufacture of gold, no one could guess that they 

 were accelerating the formation of sciences which should 

 themselves be among the most essential foundations of 

 navigation and commerce, and, through them, of civilis- 

 ation and government, peace and security, arts and liter- 

 ature. That good plants of such a species require the 

 warmth of mysticism and superstition in their early 

 growth is not a rule of absolute generality, for there are 

 cases in which cupidity and vacancy of mind will do 

 as well. Cards and dice were the early aliment of 

 the branch of knowledge before us ; but its utility is 

 now generally recognised in all the more delicate branches 

 of experimental science, in which it is consulted as the 

 guide of our erroneous senses, and the corrector of our 

 fallacious impressions. And more than this, it is the 

 source from whence we draw the means of equalising the 



