14 THE SEVEN FOLLIES OF SCIENCE 



by the Babylonians, the Chinese, and probably also by the 

 Greeks, in the earliest times. At the same time we must 

 not forget that these statements in regard to the ratio 

 come to us through historians and prophets, and may not 

 have been the figures used by trained mechanics. An 

 error of one foot in a hoop made to go round a tub or cis- 

 tern of seven feet in diameter, would hardly be tolerated 

 even in an apprentice. 



The Egyptians seem to have reached a closer approxima- 

 tion, for from a calculation in the Rhind papyrus, the ratio of 

 3. 1 6 to I seems to have been at one time in use. It is prob- 

 able, however, that in these early times the ratio accepted 

 by mechanics in general was determined by actual meas- 

 urement, and this, as we shall see hereafter, is quite 

 capable of giving results accurate to the second fractional 

 place, even with very common apparatus. 



To Archimedes, however, is generally accorded the 

 credit of the first attempt to solve the problem in a 

 scientific manner ; he took the circumference of the circle 

 as intermediate between the perimeters of the inscribed 

 and the circumscribed polygons, and reached the conclusion 

 that the ratio lay between 3^ and 3^, or between 3.1428 

 and 3.1408. 



This ratio, in its more accurate form of 3.141592 . . is 

 now known by the Greek letter TT (pronounced like the 

 common word pie), a symbol which was introduced by 

 Euler, between 1737 and 1748, and which is now adopted 

 all over the world. I have, however, used the term ratio, 

 or value of the ratio instead, throughout this chapter, as 

 probably being more familiar to my readers. 



Professor Muir justly says of this achievement of 

 Archimedes, that it is " a most notable piece of work ; the 



