COMMON THINGS. 



TIME. 



CHAPTEE II. 



31. How to observe the sun's transits. 32. Interval between them variable. 

 33. Mean and apparent time. 34. Relative changes of mean 

 and apparent time. 35. The days on which they coincide. 

 36. The Equation of time. 37. Further explained. 38. Its 

 extreme error. 39. Mean time adopted in France. 40. Un- 

 iitness of apparent time. 41. Local time varies with longi- 

 tude. 42. Equalisation of local time proposed. 43. How time- 

 pieces are regulated. 44. Mean solar hours, minutes, and seconds. 

 45. Length of sidereal day. 46. The week. 47. Opinions as to its 

 origin. 48. Both opinions erroneous. 49. Origin of the names of 

 the days. 50. First day of the week. 51. The month. 



31. THE sun presenting to an observer not merely a brilliant 

 point, as is the case with a fixed star, but a circular luminous 

 space called a DISC, of considerable magnitude, the various parts 

 of which pass the meridian at different moments of time, it is 

 LARDNER'S MUSEUM OF SCIENCE. K 129 



No. 58. 



