I'uu. 10, 1882.] 



KNOWLEDGE * 



315 



THE GREAT PYRAMID. 



By the Editor. 



BEFORE considering the characteristics of the Great 

 (Jallcry in detail, L must note one peculiarity which 

 seems to me verj' significant. 



Regarded as a sort of architectural transit instrument, 

 the (Ireat Gallery would, of course, have to ho carried up 

 to a certain height, and there open out on the level to 

 which the Pyramid had then attained, the sides and top 

 lieing carried up until the southernmost end of the Gallery 

 was completed with a vertical section like that shown in 

 Fig.52 (further on). This would be the " object end " of the 



tion of the object in right ascension, he learns the time. 

 But wliether the observer is doing one or the other of 

 these things, he must have a time-indicator of some sort. 

 Our modern astronomer has his clock, beating seconds with 

 emphatic thuds, and lie notes the particular thuds at or 

 near whicli the star crosses the so-called wires in the field 

 of view (really magnilied spider lines). We may be 

 tolerably certain that the observer in the Grand Galleiy 

 had no such liorological instrument. But he must have 

 had a time indicator of some sort (and a good one, we may 

 notice in passing), or the care shown in the construction of 

 the Gallery would have been in great part wasted. 



Now, whence could his time-sounds have been conveyed 



Syv^aakfif 



S^ockftEyr. 



Fir,. 1. — SnowiNO the Fl.\t Square Summit of tiik Pvr.vmuial Obskrvatorv 



great oliscr\ing tube. The oViserver might be anywhere 

 along the tube, according to the position of the object 

 whose transit was to be observed. 



Now notice that the most important o}>ject of transit 

 obser^•ations is to determine the time at which the objects 

 observed cross the meridian. Either the observer has to 

 determine at what time this happens, or, by noting when 

 it happens, to ascertain the time ; in one case, knowing 

 the time, he karns the position of the celestial object in 

 what is c.illed right ascension (which may bo called its 

 position measxired arownd the celestial sphere in the 

 direction of its rotation) in the other, knowing the posi- 



to him but from the upper end of the Gallery \ A time- 

 measure of .some sort — probably a clepsydra, or water- 

 clock — must have been set there, and persons appointed to 

 mark the passage of time in some way, and to note also 

 the instants when the observer or observers in the Great 

 Gallery signalled the beginning or end of transit acres.? 

 the Gallery's field of view. These time-indicating persons, 

 with their instruments, would have occupied the space 

 where now are the floors of the so-called Antechainlier and 

 King's Chamber — then, of cour.se, not walled in (or the 

 walls would have obstructed the view along the Gallery). 

 These persons themselves would i.ot obstruct the view, 



