H. G. Wells 
When the Sleeper Wakes [EPUB ebook] 

One afternoon, at low water, Mr. Isbister, a young artist lodging at Boscastle, walked from that place to the picturesque cove of Pentargen, desiring to examine the caves there. Halfway down the precipitous path to the Pentargen beach he came suddenly upon a man sitting in an attitude of profound distress beneath a projecting mass of rock. The hands of this man hung limply over his knees, his eyes were red and staring before him, and his face was wet with tears.
He glanced round at Isbister’s footfall. Both men were disconcerted, Isbister the more so, and, to override the awkwardness of his involuntary pause, he remarked, with an air of mature conviction, that the weather was hot for the time of year.
‘Very, ‘ answered the stranger shortly, hesitated a second, and added in a colourless tone, ‘I can’t sleep.’
Isbister stopped abruptly. ‘No?’ was all he said, but his bearing conveyed his helpful impulse.
‘It may sound incredible, ‘ said the stranger, turning weary eyes to Isbister’s face and emphasizing his words with a languid hand, ‘but I have had no sleep-no sleep at all for six nights.’