MOODS of VERBS. 24:5 



ftances, or a mafs (not a train) of thoughts, whic' are conceived 

 at once, and cannot be feparated and confidered in lucceffion, 

 but by a very laborious effort. Many fingle words, for exam^ 

 pie prepofitions, and moft fentences, denote fome kind of rela- 

 tion ; but we cannot, I think, conceive a relation, without 

 thinking at once of the things (two or more) that are related, 

 as well as of the relation (both in its generic and in its fpeclfic 

 nature) that fubfifts between theni. 



Mathematical propofitions are expreffions of co-exiftent 

 thoughts, the objedls of which (at lead in pure geometry) bear 

 no relation at all to time ; and thefe, to be conceived righdy or 

 at all, muft be conceived at once. Any ordinary perfon can do 

 this with refpedt to an axiom, or even a very fimple propofi- 

 tion ; and good mathematicians can do it with refpedt to very 

 long and complex theorems, fome of which ordinary people 

 find almoft infuperable diiEculty in apprehending. Part of 

 this diiEculty (as I feel very plainly in myfelf ) arifes from the 

 number of things and relations that are to be thought of at 

 once, and accordingly is not immediately removed, nor is it 

 obviated, by even the moft diftindl and juft conception of every 

 one of thofe things and relations taken fingly. Correfponding 

 to this difficulty in a learner, and juft the oppofite of it, is that 

 of a teacher of almoft any fcience, and often of a fpeaker, ei- 

 ther in a public aflembly or in common converfation, who may 

 have a clear and juft conception of a great mafs of thought, 

 which he wifhes to communicate to others, but can fcarce con- 

 trive to do fo, nor knows he well where or how to begin ; and 

 perhaps when he has begun right, or at leaft diftindlly, foon 

 falls into fuch confufion and perplexity, as makes him almoft 

 or quite unintelligible to his hearers, even when he under- 

 ftands himfelf perfedly, and may know that another, more 

 fortunate in the talent of communicating thought, has helped 

 him out, or exprefled diftindly and properly that very meaning 

 which he "was endeavouring in vain to convey to his hearers, 



H h 2 though 



