501 



mechanism for printing, or rather for furnishing stereotype plates of 

 the calculated results. 



As M. Scheutz has taken out a patent for his engine, it will be 

 unnecessary to give a detailed description of the machinery, which 

 may be obtained in the specification, a copy of which has been 

 presented to the Royal Society. It will be sufficient to give an 

 idea of its general construction and extent with a view of estimating 

 its powers. 



The machine takes in the function to be tabulated and the first 

 four orders of differences, each to fifteen digits. Of these only the 

 first eight (in the case of the function itself) are printed, the others 

 being reserved to guard against errors arising from decimal places 

 left out. 



The places of the digits are represented by fifteen vertical spindles, 

 around which, but not usually connected with which, are placed 

 horizontal wheels in five separate tiers. Each wheel has its circum- 

 ference divided into ten equal parts, and is marked with the digits 

 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. In the normal state of the machine the 

 numbers on the wheels of the highest tier represent the function 

 (u x ) to be tabulated, and those on the tiers below represent respect- 

 ively Aw,-!, ^u x _ l , AV^sj, and AVj._ 2 . In each case the digits 

 by which these numbers are represented run from left to right, as in 

 print. The mechanism is such, that by turning a handle continuously 

 in one direction an indefinite succession of movements is produced 

 which are alternately backwards and forwards. The effect of the 

 forward motion is, that the numbers on the third and the fifth tiers 

 (or as they may conveniently be called the A 2 and A 4 tiers) add them- 

 selves respectively to those on the tiers above, altering thereby the 

 positions of the wheels of the A 1 and A 3 tiers, while the wheels of 

 the A 2 and A 4 tiers remain at rest ; and the backward motion does 

 for the A 1 and A 3 tiers what the forward motion does for the A 2 and 

 A 4 tiers. Thus the numbers on the several tiers will be as follows : 



At first MJ, AM,,,_I A 2 w. r _ 1 A 3 M,y_ a A 4 ,_ a ; 



After the forward motion .... u x Aw,,. &" u x -i A^.j AV,._ 3 ; 

 After the complete motion . . u jc+l Aw^, A^ A 3 .,._i A 4 jr _ 1 

 A 4 "*-! in the last term being written instead of A 4 4 ._ 2 , which is 



