372 
Proceedings of the Royal Society 
the difference between pure mathematics and applied ? or, Is he 
unjustly and knowingly stating against the Pyramid’s deduced 
standards, as an acknowledged metrological fact, that of which he 
knows the very contrary has been found to prevail by all those 
men who have devoted themselves specially to the most accurate 
possible mensurations. 
Into this nice question I shall not attempt to penetrate, — but will 
pass on to a statement at the foot of the same Proceedings’ page, 
asserting that u our real practical standard measures are infinitely 
“ more refined and many thousand-fold more delicate than any in- 
“ definite and equivocal measures alleged to be found in the Py- 
“ ramid by even those who are most enthusiastic in the pyramidal 
“ metrological theory.” 
This is clearly stated there, and then its writer brings forward 
as proofs of that infinitely superior accuracy, refinement, and 
delicacy, the thickness-gauges of Mr Whitworth. 
Now these gauges are no doubt very admirable things in their 
way and in their own place ; and as they range generally from 0‘2 to 
6'0 inches in diameter, they are exceedingly useful for testing the 
thickness of iron rods and plates in engineers’ workshops. But 
they are not yet employed by the Government as the standard 
length of the country ; they would form also a most awkward shape 
for a standard to refer to, in measuring any long length on the 
surface of the earth ; and from their shortness, would require 
to be multiplied so often as to lead to serious chances of error ; 
while finally comes the question, are they adapted to last ? 
A national or scientific standard ought to hand down the national 
measure unchanged for thousands of years. But will so oxidizable a 
substance as iron, and this is what Mr Whitworth employs, be safe 
through such long ages ? When so little of the iron of the Greeks 
and Romans, and less of the Egyptians, has come down to our 
time — grave fears may be entertained for the Manchester iron 
plugs and sockets. 
Now the standard of the Great Pyramid, on the contrary, comes 
before us with the proof on its brow of having stood that test, 
which Mr Whitworth’s thickness gauges have not yet gone through ; 
— viz., of having lasted before the world, and in spite of conquer- 
ing and insulting nations, for 4000 years. In spite too of conquerors 
