220 A HISTORY OF 



mediately snatched into a dark room, will appear still luminous: and 

 it will be some time before it is totally darkened. It is thus with the 

 eye; which, either by an instant gaze at the sun, or a steady conti- 

 nuance upon some less brilliant object, has taken in too much light ; 

 its humours are, for a while, unfit for vision, until that be discharged, 

 and room made for rays of a milder nature." How dangerous the 

 looking upon bright and luminous objects is to the sight, may be easily 

 een, from such as live in countries covered for most part of the year 

 with snow, who become generally blind before their time. Travel- 

 lers who cross these countries, are obliged to wear a crape before their 

 eyes, to save their eyes, which would otherwise be rendered totally 

 unserviceable ; and it is equally dangerous in the sandy plains of Africa. 

 The reflection of the light is there so strong, that it is impossible to 

 sustain the effect, without incurring the danger of losing one's sight 

 entirely. Such persons, therefore, as read or write for any continu- 

 ance, should choose a moderate light, in order to save their eyes; and, 

 although it may seem insufficient at first, the eye will accustom itself 

 to the shade, by degrees, and be less hurt by the want of light than 

 the excess. 



" It is, indeed, surprising how far the eye can accommodate itself 

 to darkness, and make the best of a gloomy situation. When first 

 taken from the light, and brought into a dark room, all things disap- 

 pear ; or, if any thing is seen, it is only the remaining radiations that 

 still continue in the eye. But, after a very little time, when these are 

 spent, the eye takes the advantage of the smallest ray that happens to 

 enter ; and this alone would, in time, serve for many of the purposes 

 of life. There was a gentleman of great courage and understanding, 

 who was a major under Kinp Charles I.; this unfortunate man, sha- 

 ring in his master's misfortunes, and being forced abroad, ventured at 

 Madrid to do his king a signal service; but, unluckily, failed in the 

 attempt. In consequence of this, he was instantly ordered to a dark 

 and dismal dungeon, into which the light never entered, and into 

 which there was no opening but by a hole at the top, down which the 

 keeper put his provisions, and presently closed it again on the other 

 side. In this manner the unfortunate loyalist continued for some 

 weeks, distressed and disconsolate; but at last he began to think he 

 saw some little glimmering of lip;ht. This internal dawn seemed to 

 increase from time to time, so that he could not only discover the 

 parts of his bed, and such other lar^ objects, but, at length, he even 

 began to perceive the mice that frequented his ceH; and saw them as 

 they ran about the floor, eating the crumbs of bread that happened to 

 fall. After some months' confinement be was at last et free; but 

 such was the effect of the darkness upon lira, that he cou'd not for 

 tome days venture to leave his dungeon, but was 

 himself by degrees tc tne light o' the day. 



