18 THE SEVEN FOLLIES OF SCIENCE 



mind, but when we come to use six and seven hundred 

 places the results are simply astounding. Professor 

 De Morgan, in his " Budget of Paradoxes," gives the fol- 

 lowing illustration of the extreme accuracy which might be 

 attained by the use of 607 fractional places, the highest 

 number which had been reached when he wrote : 



" Say that the blood-globule of one of our animalcules 

 is a millionth of an inch in diameter. 1 Fashion in thought 

 a globe like our own, but so much larger that our globe is 

 but a blood-globule in one of its animalcules ; never mind the 

 microscope which shows the creature being rather a bulky 

 instrument. Call this the first globule above us. Let the 

 first globe above us be but a blood-globule, as to size, in the 

 animalcule of a still larger globe, which call the second 

 globe above us. Go on in this way to the twentieth globe 

 above us. Now, go down just as far on the other side. 

 Let the blood-globule with which we started be a globe 

 peopled with animals like ours, but rather smaller, and 

 call this the first globe below us. This is a fine stretch of 

 progression both ways. Now, give the giant of the twen- 

 tieth globe above us the 607 decimal places, and, when he 

 has measured the diameter of his globe with accuracy 

 worthy of his size, let him calculate the circumference of 

 his equator from the 607 places. Bring the little phil- 

 osopher from the twentieth globe below us with his very 

 best microscope, and set him to see the small error which 



1 What follows is an exceedingly forcible illustration of an important 

 mathematical truth, but at the same time it may be worth noting that 

 the size of the blood-globules or corpuscles has no relation to the 

 size of the animal from which they are taken. The blood corpuscle 

 of the tiny mouse is larger than that of the huge ox. The smallest 

 blood corpuscle known is that of a species of small deer, and the 

 largest is that of a lizard-like reptile found in our southern waters 

 the am phi um a. 



These facts do not at all affect the force or value of De Morgan's 

 mathematical illustration, but I have thought it well to call the atten- 

 tion of the reader to this point, lest he should receive an erroneous 

 physiological idea, 



