TERMS. 37 



S = of specific gravity 10*5, 



T = melting above ioooC, 



V = good conductor of heat and electricity, 

 then we can form a combined term PQRSTV, which will 

 denote 'a white monovalent metal, of specific gravity 

 10*5, melting above ioooC, and a good conductor of heat 

 and electricity/ 



There are many grammatical rules or usages concerning 

 the junction of words and phrases to which we need pay 

 no attention in logic. We can never say in ordinary 

 language * of wood table/ meaning ' a table of wood/ 

 but we may consider 'of wood' as logically an exact 

 equivalent of * wooden ' ; so that if 



X = of wood, 

 Y = table, 



there is no reason why, in our symbols, XY should not be 

 the correct term for ' table of wood/ In this case indeed 

 we might substitute the corresponding adjective 'wooden/ 

 but we should often fail to find any adjective answering 

 exactly to a phrase. There is no single word which could 

 express the notion * of specific gravity 10*5 ' : but logically 

 we may consider these words as forming an adjective ; and 

 denoting this by S and metal by P, we may say that SP 

 means 'metal of specific gravity 10*5.' It is one of many 

 advantages in these blank letter-symbols that they enable 

 us completely to abstract all grammatical peculiarities and 

 fix our attention solely on the purely logical relations 

 involved. Investigation will probably show that the rules 

 of grammar are mainly founded upon traditional usage 

 and have little logical signification. This indeed is suffi- 

 ciently proved by the wide grammatical differences which 

 exist between languages where the logical foundation must 

 be the same. 



