126 



THE PRINCIPLES OF SCIENCE. 



If there be a second premise, for instance 



B=BC, 

 we press in like manner the keys 



B (subj.), copula, B (pred.), C (pred.), full stop. 

 The process is exactly the same however numerous the 

 premises may be. When they are completed the operator 

 will see indicated on the face of the machine the exact 

 combinations of letters which are consistent with the 

 premises according to the principles of thought. 



As shown in the figure opposite the title-page, the 

 machine exhibits in front an abecedarium of sixteen com- 

 binations, exactly like that of the abacus, except that the 

 letters of each combination are separated by a certain 

 interval. After the above problem has been worked upon 

 the machine the abecedarium will present the following 

 appearance 



A A 



a a a a 



B B 



B B 



b b b b 



D d 



D I d 



d D d 



The operator will collect the various conclusions, as for 

 instance that A is always C, that not-C is not-B and 

 not- A ; that not-B is not- A but either C or not-C, as 

 in the use of the Logical Slate or Abacus. 



