DIALS AND CLOCKS. 75 



at 5 o'clock, it will then be shown at V, by the shadow on the 

 western side of the dial, and the shadow cannot be observed on the 

 dia>to advantage much later than 5 o'clock, Suppose, then, the 

 dial located, and that when the shadow indicates XII, or apparent 

 noon, a well regulated clock is started, the hands of which also 

 indicate XII, and this on the 24th day of December, for, as we 

 shall soon see, this is one of the four days in the year when the 

 clock and dial agree, then, although for a few days, the clock and 

 dial will .appear to indicate the hour of noon together, it will soon 

 be observed, that the clock begins to gain on the dial, and after 

 an interval of one month, the clock will show 12h, 13m, when the 

 dial indicates noon, or 12 o'clock apparent time. This difference 

 will go on increasing, until February 10th, or llth, when the 

 clock will appear to lose time, and by the 25th of March will be 

 only 6m. faster than the dial, and on the 15th day of April they 

 will again correspond. The clock, after this, will continue, appa- 

 rently, to lose time until about May 15th, at which time it will 

 only indicate llh, 56m, when the dial shows noon ; after this, its 

 rate seems to increase, and on the 16th day of June they again 

 come together. The clock now continues to gain on the dial until 

 July 25th, when it is about 6m, 4s, faster, after which, its rate 

 apparently decreases, until at August 31, they again coincide. 

 On the 2d of November, the clock shows llh, 43m, 46s, when 

 the dial says it is noon ; this is the greatest difference of all, being 

 16m, 14s, after this they begin to come together, and on December 

 24th, again correspond. Now, can it be that the sun's motion in 

 the heavens, or rather the earth's motion, is thus irregular ? We 

 might, at first, suspect our clocks, and watches, but the utmost 

 pains have been bestowed on these, and when their rates of going 

 have been ascertained, by means of the stars, and a transit instru- 

 ment, as already described, they are found to go perfectly uniform, 

 or very nearly so. Hence we are forced to admit, that the dis- 

 crepancy between the dial and the clock, is to be sought for in the 

 movements of the earth, and we shall fully show, in our next 

 chapter, what these are. 



Thus far we hope we have succeeded in explaining the phe- 

 nomena of the heavens due to the movements of the earth, nnd 



