OF THE VELOCITY OF MOTION OF THE WAVE-PARTICLE. 77 



But -this tomb can be made to yield more valuable data for the deter- 

 mination of the velocity of wave-particle. The top slab, described as hav- 

 ing- been shot clear off the tomb to a distance of 8 feet to the north, was 

 evidently projected in the same manner as the cap of the gate pillar, but 

 the case is not quite so simple. The twisting- of the stone on its axis 

 through an angle of 5° need not be noticed, as many causes might have led 

 to this, and it will not affect the accuracy of the results to be obtained in 

 any appreciable degree. A much more serious complication is introduced 

 by the iron railings, which, as is shown in PI. X, fig. 2, are all torn up 

 and bent over ; the question to be decided is how much of this must be 

 attributed to the capping slab and how much to the weight of the upper 

 portion of the tomb which was precipitated on to them and is shown in 

 the figure lying on the bent-down rails. These railings were made of 

 iron rods f inch square, flattened out into a spear-head at the top, near to 

 which they were leaded into a horizontal bar of iron 2 inches broad by 

 \ an inch thick. The tops of those bars which lay in the path of the 

 heavy marble slab were bent over at a right angle, evidently by its drive, 

 thus showing that the slab was shot clear off the top of the tomb and 

 that it must have hit the rails close to their upper ends; indeed, it 

 is very probable that the bending was produced by the bottom of the 

 slab knocking against the tips of the spear-heads, and as at the same 

 or almost the same moment the whole of the overturned upper portion 

 of the tomb was precipitated on to the rails, it is probable that the 

 motion of the slab was arrested to but a small degree ; in any case, this 

 slab will give a useful minimum measure of the velocity of wave-particle. 



The formulas will, of course, be the same as in the case of the cap of 

 the gate pillar ; here a = 8 feet 1^ inch and b = 5 feet 4 inches. 



v = 14' 06 feet per second. 

 This is a little more than 4 feet per second less than the value given by 

 the cap of the gate pillar, the difference being due to the velocity 

 absorbed in bending the rails. If, as before, we take the superficial angle 

 of emergence at 30°. 



V = 14*06 sec, 30°. 



= 16 s 22 feet per second. 



( 77 ) 



