684 PKOF. C. P. SMYTH ON THE REPUTED METROLOGICAL SYSTEM 



The three chief authorities who, for accuracy, distance all the rest, are 



Professor Greaves in 1638, 



M. JoMARD in 1800, 



And Howard Vyse in 1839. 



Yet even on their measures it would be dangerous to speculate on what the out- 

 side dimensions of the coflPer may be, to within an inch or two. 



Fortunately, for a capacity measure, we have not to pay much attention to 

 the exterior ; and the inside dimensions are given with less uncertainty. Never- 

 theless, Howard Vyse's are rude beyond toleration in such a case (only to the 

 nearest half inch) ; and the French measures are vitiated in the depth element, 

 by a blunder of nearly three inches ; i. e., it seems so to my best judgment. 



Hence, the ancient Oxford Professor is the only authority left outstanding ; 

 and happy it is that he so far transcended his age's ideas of accuracy in such 

 admeasurements; and thought, too, so much more of the interior, than the exterior. 



There is, indeed, some doubt as to the real value of the length of a foot on the 

 scale employed by Greaves, and that known as the English foot in the present 

 day ; and there, the French academicians have done good service ; for Greaves, 

 immediately after his measure of the coffer in 1638, marked off the length of one 

 foot of his scale on the unchanging granite of the walls of the chamber; and 

 these marks being visible in 1799, M. Jomard measured them and found them 

 = 0"3046 of a French metre; whence, on the understanding that one French 

 metre is equal to 39-37079 modern English inches, we have the following corrected 

 statement of Greaves' measure, viz. — 



Interior length =77-806 

 breadth = 26-599 

 depth =34-298 



and these being multiplied together, yield 



70,982-4 



English cubic inches, as the observed contents of the Pyramid coffer. 



If we then turn to the British Act of Parliament defining from the bushel the' 

 number of cubic inches in a " Quarter," and multiply that by 4, we have, 



70,982-l ; 



a closeness of approach which is something more than startling. 



As to the material of this remarkable vessel, it would be hazardous to venture 

 much upon what it is exactly, seeing that it has been described as everything, 

 from black marble to red granite ; but we rather incline, from private informa- 

 tion, to " porphyry;" and, in the event of the metrological character being fully 

 established, it would be important to ascertain both precisely what sort of 

 porphyry it is, and where it came from. At present, we must rest satisfied, with 



