CONTRIVANCE. 15 



thought, to which we give the name of " inven- 

 tion" or "contrivance," is very valuable. It is 

 done in very little time, and with no labour, for 

 there is no weight to be moved, and no resistance 

 to be overcome. A skilful architect will, in his 

 own mind, rear a palace, before a brickmaker can 

 mould and burn a single brick, a mason fetch a 

 stone from the quarry, or a woodman fell a tree ; and 

 he will feel none of the fatigue and exhaustion which 

 they feel. We are, indeed, accustomed to say that 

 the mind is fatigued ; and when we long continue 

 thinking on the same subjects, especially if there 

 is any thing dispiriting in them, we do feel a sort 

 of languor, and pass into a reverie or dreamy 

 state, in which we not only lose the command of 

 our bodies, as we do during slumber, but in the 

 end lose the memory of our thoughts, just as we 

 do in profound sleep, during which we have no 

 dreams. Every body must recollect instances of 

 having thought upon subjects till the memory of 

 all the particulars was gone ; and, when an author 

 writes an original book upon any subject that re- 

 quires close and profound thinking, the chance is 

 that he shall know less of what is in the book after he 

 has just finished the writing of it, than an intelligent 

 reader after he has glanced it over. " Don't ask 

 me about that, for I have written upon it," was a 

 habitual saying with a veteran both in science and 

 literature ; and Abernethy's constant referring of 

 his patients to " My Book," had philosophy in it, 

 whether he understood that philosophy or not. 



This fact, that we not only can, but actually 

 and often do, think ourselves out of thought and 

 the power of thinking, is a very important mat- 

 ter, and one which shows, perhaps more strikingly 

 c 2 



