274 Vroceedmgs of th Albany Institute. 



may remark, is totally different from the one contemplated 

 by Mr. Babbage. 



The Scheiitz engine was put in operation at the Dudley 

 Observatory for a shorl time, id the year 1858, but Bince 

 thai time it has not been in working order. When we 

 undertook the study of it, a Bhorl time Bince, it was found 

 to be so much out of repair and in such a state of contu- 

 sion, that it seemed almost impossible to discover the 

 mechanical principles on which it was based; but from the 

 study of its details, in a few days the theory of the me- 

 chanism was revealed, after which it was an easy matter 

 to restore the whole theory of the machine for making any 

 class of computations comprised within its limits. 



Prof. Hough then proceeded to explain the principle 

 upon which the mechanism is arranged. Its fundamental 

 principle is based on the mathematical truth, that in any 

 series of numbers the ninth order of difference will be zero, 

 when n may be any number whatever. This machine is 

 constructed for four orders of differences, and will conse- 

 quently compute any series in which the fourth orders of 

 differences are equal. 



The manner in which the differences were marked by 

 the various wheels, was illustrated by a specimen brought 

 from the machine and by diagrams on the board, after 

 which some particulars were given of the action of the 

 machine. It may be used to fifteen places of figures, of 

 w hi eh eight places are printed at the time of making the 

 calculation. Thirty seconds is the time necessary for a 

 complete result. 



Before starting the machine for any computation, it is 

 necessary to set the appropriate wheels, after which it needs 

 no further attention; for so long as the last order of dif- 

 ferences is constant, it will continue to produce the re- 

 quired numbers. Thus, for producing a table of squares it 

 is only necessary to give the machine three numbers 1, 3, 



