662 THE POPULAR SCIENCE MONTHLY. 



as and often better than they can in consciousness, ■when they largely 

 rely upon an artificial time-computer. In doing this they may per- 

 form an intellectual process similar in all respects to the conscious act 

 of calculating a distance between known i:)oints. 



Third. This division covers a wide field of intellectual activity, and 

 the inquiry is here directed to the result of systematically connected 

 thought, omitting only original research which is considered later. 

 Is there unconscious reasoning of a complex kind employed when old 

 work begun in consciousness is carried on or brought to a logical con- 

 clusion unknown to the thinker, as in the cases of solving mathematical 

 problems and the like ? Let the facts speak for themselves : 



1. Mr. T , of Metuchen, New Jersey, writes : "I liad earnestly 



been trying to make a trial-balance, and had at last left off working — 

 the summary of the Dr. and Cr, sides of the account showing a differ- 

 ence of £2 10s. Od.y the Dr. side being so much smaller. The error I 

 had not found on Saturday night when I left the counting-house. On 

 this same Saturday night I retired, feeling nervous and angry with 

 myself. Some time in the night I dreamed thus : I was seated at my 

 desk in the counting-house and in a good light ; everything was orderly 

 and natural, the ledger lying open before me. I was looking over 

 the balances of the accounts and comparing them with the sums in 

 the trial balance-sheet. Soon I came to a small account having a 

 debit balance of £3 10s. Qd. I looked at it, called myself sundry 

 uncomplimentary names, spoke to myself in a deprecating manner of 

 my own eyes, and at last put the £2 10s. Od. to its proper side of 

 the trial balance-sheet, shut up and went home. Here the dream ab- 

 ruptly ended. I arose at the usual Sunday time, dressed carefully, 

 breakfasted, wont to call upon some young lady friends, and to go to 

 church, especially with one of them. Suddenly, the dream flashed 

 on my memory. I went for the keys, opened the ofiice, also the 

 safe : got the ledger, turned to the folio my dream indicated. There 

 was the account whose balance was the sum wanted, and which I 

 had omitted to put in the balance-sheet where it was now put, and my 

 year's posting proved correct." 



2. Mrs. R , of Wakefield, Rhode Island, writes : " When per- 

 plexed by work, often leave it and find the thing easy after a little while. 

 Once, while working at a chess-puzzle for several evenings, I went to 

 bed, fell asleep, and worked it correctly ; sprang out of bed, found it 

 correct, and wrote it down for fear of forgetting it ; found it right in 

 the morning. I had worked at the puzzle so long that it was perfectly 

 familiar, and, before going to sleep, lay thinking of new moves ; the 

 right one was merely a continuation of my waking thoughts." 



3. Mr, S , of New York city, writes : " I remember but one 



instance, in which case, when about nineteen years of age, I correctly 

 solved a mathematical problem, during a sound sleep, so far as I could 

 judge, which had puzzled mc before going to bed." 



