352 



Accouni of an Arithmetical Machine 

 4 5 6 7 



[Mat, 



Product 1 -'A •■ 8 ' 8 • 8 •' k ' 2 



The great mathematician, Napier, afterwards employed this 

 method in tlie construction of his virgulaj lamellae, both of which 

 are descrihe 1 in the Rabdologia published by him in I6I7. 



I lately met with a small arithmetical machine consisting of a 

 di-- position of Napier's rods, which is not described in his Rabdo- 

 logia. Tl>is system is contained in a small box of oak. It was 

 found amongst some old books in the library of the University of 

 Edinburgh, and was probably made after the time of Napier. 



The annexed diagram, winch is about two-thirds the size 

 of the original, represents the box when open ; the hinge 

 is on the line C D, and A, B, C, D, is the lid ; the table inscribed 



R 



S 



E 



H 



K 



u 



B 



D 





