THK SUNniAI. AND THE CLOCK. Ill 



Time, so that on this clay again standard watch and sundial 

 noon fall together nearly enough ; not exactly. 



After June 14th the sun is behind, and more and more 

 behind until July 26th when he begins to move faster and 

 to overtake mean sun. He does so in fact on Sep. ist which 

 is again Zero Day ; and completes the circuit of the year. 



Now the sundial, owing to penumbra and other causes, 

 roughness of manufacture and almost inevitable lack of accu- 

 rate adjustment always allows a possible error of from ten to 

 twenty seconds. It is not a scientific instrument at all. 



Moreover, the equation of time is not the same by several 

 seconds on the same da}' of every year. This is one of the 

 apparent but self-compensating irregularities by which the 

 Creator has provided for the stability of the system. 



And, finally, though it is usually so taken for granted 

 even in the text books the moment of exact accord between 

 sundial and local mean solar is not noon precisely on Zero 

 Day. As will be seen by a look into that final arbiter, the 

 Nautical Almanac. 



I shall now quit didactics altogether and offer you a kind 

 of dream of astronomical architecture. 



It would be entirely within the resources of science to 

 study all this dream out and explain it ; but I have not done 

 so, and do not mean to. Ver\' vague, therefore, is my notion 

 of the specific use to which the structures you are to hear of 

 are put. What I wish to set before you is an idea of the 

 mighty works that may shew themselves forth on the lines 

 shadowed out hereinbefore, and the exemplary regardlessness 

 of cost evinced by some Oriental rulers when they put their 

 trust in men of science. 



I read the chapter in the June number ( 1840) of the old 

 Penny Magazine while I was a boy and came across it by 

 chance only the other day. 



The (Uiutur Muntur (or Roval Observatorv ) of Delhi was 



