Page:Curious myths of the Middle Ages (1876).djvu/661



HE laws governing numbers are so perplexing to the uncultivated mind, and the results arrived at by calculation are so astonishing, that it cannot be matter of surprise if superstition has attached itself to numbers.

But, even to those who are instructed in numeration, there is much that is mysterious and unaccountable, much that only an advanced mathematician can explain to his own satisfaction. The neophyte sees the numbers obedient to certain laws, but why they obey these laws he cannot understand; and the fact of his not being able so to do, tends to give to numbers an atmosphere of mystery which impresses him with awe.

For instance, the property of the number 9, discovered, I believe, by W. Green, who died in 1794, is inexplicable to any one but a mathematician. The property to which I allude is this, that when 9 is multiplied by 2, by 3, by 4, by 5, by 6, &c., it will be found that the digits composing the product, when added together, give 9. Thus:

2 × 9 = 18, and 1 + 8 = 9 3 × 9 = 27 2 + 7 = 9 4 × 9 = 36  3 + 6 = 9