286 POPULAR LECTURES AND ADDRESSES. 



advance to logic, and consider logic as the 

 science of using words, to lead him to know ex- 

 actly what he means by them when he uses them. 

 More ships have been wrecked through bad logic 

 than by bad seamanship. When the captain writes 

 down in his log I don't mean a pun here, log 

 has nothing to do with logic the ship's place 

 is so-and-so, he means that it is the most probable 

 position the position which, according to previous 

 observations, he thinks is the most probable. 

 After that, supposing no sights of sun or stars 

 or land to be had, careful observation of speed 

 and direction shows, by a simple reckoning (called 

 technically the dead-reckoning], where the ship 

 is next day. But sailors too often forget that 

 what they put down in the log was not the ship's 

 place, but what to their then knowledge was the 

 most probable position of the ship, and they keep 

 running on as if it was the true position. They 

 forget the meaning of the very words in which 

 they have made their entry in the log, and through 

 that bad logic more ships have been run on the 

 rocks than by any other carelessness or bad sea- 





