TWENTY-SIXTH CONGRESS, 1839-41. 217 



-every point of the compass, at the fiat of his will, without 

 feeling a thrill of amazement approaching to superstition? 

 The discovery of the attractive power of the magnet was 

 made before the invention of the alphabet or the age of 

 hieroglyphics. No record of the event is found upon the 

 annals of human history; but seven hundred years have 

 scarcely passed away since its polarity was first known to 

 the civilized European man. It was by observation of the 

 periodical revolution of the earth in her orbit round the 

 sun, compared with her daily revolution round her axis, 

 that was disclosed the fact that her annual period was com- 

 posed of 365 of her daily revolutions, or, in other words, 

 that the year was composed of 365 days ; but the shepherds 

 of Egypt, watching their flocks by night, could not but 

 observe the movements of the Dog-star next to the sun, 

 the most brilliant of the luminaries of heaven. They wor- 

 shipped that star as a god ; and losing sight of him for 

 about forty days every year, during his conjunction with 

 the sun, they watched with intense anxiety for his reappear- 

 ance in the sky, and with that day commenced their year. 

 By this practice, it failed not soon to be found that, although 

 the reappearance of the star, for three successive years, was 

 at the end of 365 days, it would on the fourth year be de- 

 layed one day longer ; and after repeated observation of 

 this phenomenon, they added six hours to the computed 

 duration of the year, arid established the canicular period 

 of four years, consisting of 1,461 days. It was not until 

 the days of Julius Caesar that this computation of time was 

 adopted in the Roman calendar ; and fifteen centuries from 

 that time had elapsed before the yearly celebration of the 

 Christian paschal festivals, founded upon the Passover of 

 the Levitical law, revealed the fact that the annual revolu- 

 tion of the earth, in her orbit round the sun, is not precisely 

 of 365 days and one quarter, but of between 11 arid 12 

 minutes less ; and thus the duration of the year was ascer- 

 tained, as a measure of time, to an accuracy of three or 

 four seconds, more or less a mistake which would scarcely 

 -amount to one day in twenty thousand years. 



It is, then, to the successive discoveries of persevering 

 astronomical observation through a period of fifty centuries 

 that we are indebted for a fixed and permanent standard 

 for the measurement of time. And by the same science 

 has man acquired, so far as he possesses it, a standard for 

 the measurement of space. A standard for the measure- 

 ment of the dimensions and distances of the fixed stars 

 from ourselves is yet to be found ; and, if ever found, will 



