28 DISCOURSE ON THE STUDY 



physical astronomy an approach to the miraculous. 

 Yet, the alternatives of life and death, wealth and 

 ruin, are daily and hourly staked with perfect con- 

 fidence on these marvellous computations, which 

 might almost seem to have been devised on purpose 

 to show how closely the extremes of speculative 

 refinement and practical utility can be brought to 

 approximate. We have before us an anecdote com- 

 municated to us by a naval officer*, distinguished for 

 the extent and variety of his attainments, which 

 shows how impressive such results may become in 

 practice. He sailed from San Bias on the west 

 coast of Mexico, and after a voyage of 8000 miles, 

 occupying 89 days, arrived off Rio de Janeiro, hav- 

 ing, in this interval, passed through the Pacific 

 Ocean, rounded Cape Horn, and crossed the South 

 Atlantic, without making any land, or even seeing a 

 single sail, with the exception of an American whaler 

 off Cape Horn. Arrived within a week's sail of Rio, 

 he set seriously about determining, by lunar observ- 

 ations, the precise line of the ship's course and its 

 situation in it at a determinate moment, and having 

 ascertained this within from five to ten miles, ran the 

 rest of the way by those more ready and compen- 

 dious methods, known to navigators, which can be 

 safely employed for short trips between one known 

 point and another, but which cannot be trusted in 

 long voyages, where the moon is the only sure guide. 

 The rest of the tale we are enabled by his kindness 

 to state in his own words : " We steered towards 

 Rio de Janeiro for some days after taking the lunars 



* Captain Basil Hall, R. N. 



