TWENTY-SIXTH CONGRESS, 1839-1841. 197 



dred 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 hei 

 annual period was composed of 365 of her daily revolutions, or, in 

 other words, that the year was composed of 365 days; but the shep- 

 herds 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 worshiped that star as a god; and 

 losing sight of him for about forty days every year, during his con- 

 junction with the sun, they watched with intense anxiety for his 

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

 this practice, it failed not soon to be found that, although the reap- 

 pearance of the star, for three successive years, was at the end of 365 

 days, it would on the fourth year be delayed one day longer; and after 

 repeated observation of this phenomenon, they added six hours to the 

 computed duration of the year, and 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 revo- 

 lution of the earth, in her orbit round the sun, is not precisely of 365 

 days and one-quarter, but of between 11 and 12 minutes less; and thus 

 the duration of the year was ascertained, 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 20,000 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 be through the means of 

 astronomical observation. The influence of all these discoveries upon 

 the condition of man is, no doubt, infinitely diversified in relative 

 importance; but all, even the minutest, contribute to the increase and 

 diffusion of knowledge. There is no richer field of science opened to 

 the exploration of man in search of knowledge than astronomical 

 observation; nor is there, in the opinion of this committee, any duty 

 more impressively incumbent upon all human governments than that 

 of furnishing means and facilities and rewards to those who devote 

 the labors of their lives to the indefatigable industry, the unceasing 

 vigilance, and the bright intelligence indispensable to success in these 

 pursuits. 



