CALCULA TING-MA CHINES. 



451 



formance of the machine. With this instrument, which my children 

 learned to use when they were seven years old, the product of two 

 numbers of ten digits can be obtained in half a minute ; and it is 

 used in numerous offices and institutions in France, the average sale of 

 it being a hundred a year. 



About a half a century ago, Charles Babbage undertook the con- 

 struction of a universal calculating-machine, which should give the 

 successive terms of arithmetical progressions of different orders ; but, 

 having devoted the latter part of his life, and all of his fortune and 

 income to it, died without finishing it. George Scheutz, of Stockholm, 

 and his son, Edward Scheutz, exhibited a machine at the Paris Exposi- 

 tion of 1855, which was bought by a citizen of the United States and 

 presented to the Dudley Observatory in Albany. It is shaped like a 

 small piano, and by simply turning the handle gives out the successive 

 terms of arithmetical progressions, not of the first order only, but of 

 the second, third, and fourth orders. 



Fig. 13.— The Table op Ptthagoras on Slats. 



John Napier, the inventor of logarithms, suggested an ingenious 

 method of performing the operations of multiplication and division. 

 The table in Fig. 13 represents the table of Pythagoras dissected into 



