8o THE BOOK OF NATURE STUDY 



We have already attempted to show that sunset is merely 

 an appearance, and that the farther we go west the later it is 

 before that appearance develops. Further, by means of our 

 shadow observations, compared with the clock, we have tried 

 to show that, supposing our school to be, say, 3 degrees west 

 of Greenwich, then noon is twelve minutes later. We have 

 compared this result with the result obtained by studying the 

 tables showing " ligh ting-up time/' and in this way we have seen 

 that to persons west of Greenwich the sun rises later, comes 

 to its highest point later, and sets later than to persons at Green- 

 wich, this being true for all seasons of the year. For all persons, 

 then, in Great Britain who live to the west of Greenwich the clock 

 is fast, just as it is slow to the comparatively few persons who, 

 in Great Britain, live to the east of Greenwich. Over most of 

 Great Britain the difference is comparatively small, but we note 

 that a little boy who lives, say, at Fishguard in Pembrokeshire, 

 and who goes to bed at eight o'clock, is really going to bed at 

 twenty minutes to eight by the sun. But then he has the con- 

 solation of knowing that when he gets up at half -past seven by 

 the clock, it is really only ten minutes past ! 



We may notice, also, that so long as there were no railways 

 it did not matter very much whether people took sun time or 

 Greenwich time. The extreme difference produced by difference 

 in longitude in Great Britain is only about twenty-four minutes, 

 and so long as one has not a train to catch twenty-four minutes 

 more or less does not make much difference. It was only when 

 railways became common that Greenwich time came to be 

 universally adopted in Great Britain. Without the electric 

 telegraph, also, it would be impossible to have all the clocks in 

 Great Britain keeping Greenwich time, so that the occurrence 

 of one time over a country is necessarily a modern development. 



One should also notice that while in Great Britain the maxi- 

 mum difference between sun time and clock time produced by 

 a difference in longitude scarcely exceeds twenty-four minutes, in 

 Galway in Ireland, which is 9 degrees west of Greenwich, sun time 

 is thirty-six minutes slow by Greenwich. Further, there is no 

 point in Ireland where the difference between sun time 

 and Greenwich time is less than about twenty-two minutes. 



