394 PHILOSOPHICAL TRANSACTIONS. [aNNO 1778. 



Grande ; but they do not possess the same virtues, at least not in so great a 

 degree. 



The east and west parts of the island rise into high mountains ; but the middle 

 is low, interspersed with round conic hills, all of which have very recent marks 

 of fire ; all the parts below the surface consisting of melted lava lying very 

 hollow. Most of the mountains to the westward have their tops hollowed out 

 like a punch-bowl, and contain water. Near the west end is an immense deep 

 valley, like the Furnas, called the Sete Cidades, or Seven Cities, This valley is 

 surrounded with very abrupt mountains, about 7 or 8 leagues round ; in the 

 bottom is a deep lake of water, about 3 leagues in circuit, frequented by great 

 numbers of water fowls. This water has no mineral quality ; neither are there 

 any hot springs in the valley. All these mountains are composed of a white 

 crumbly pumice stone, which is so loose, that if a person thrust a stick into the 

 banks, whole waggon loads of it will tumble down. Should any person venture 

 so far as this island for his health, a small stock of the superfluities of life only 

 need be laid in, as the island yields every necessary. The climate is very tem- 

 perate: the thermometer commonly from 70° to 75°. 



XXPIl. An Account of a Remarkable Imperfection of Sight. In a Letter from 

 J. Scott to the Rev. Mr. fVhisson, of Trin. Coll. Camb. p. 6l 1. 



I am very willing to inform you of my inability concerning colours, as far as I 

 am able from my own common observation. It is a family failing : my father 

 has exactly the same impediment : my mother and one of my sisters were perfect 

 in all colours: my other sister and myself alike imperfect: my last-mentioned 

 sister has 2 sons, both imperfect ; but she has a daughter who is very perfect : I 

 have a son and daughter, who both know all colours without exception ; and so 

 did their mother : my mother's own brother had the like impediment with me, 

 though my mother, as mentioned above, knew all colours very well. 



I will now inform you what colours I have the least knowledge of. I do not 

 know any green in the world ; a pink colour and a pale blue are alike, I do not 

 know one from the other. A full red and a full green the same, I have often 

 thought them a good match ; but yellows, light, dark, and middle, and all de- 

 grees of blue, except those very pale, commonly called sky, I know perfectly 

 well, and can discern a deficiency, in any of those colours, to a particular 

 nicety : a full purple and deep blue sometimes baffle me. I married my daughter 

 to a genteel, worthy man, a few years ago ; the day before the marriage he came 

 to my house, dressed in a new suit of fine cloth clothes. I was much displeased 

 that he should come (as I supposed) in black : said, he should go back to change 

 his colour. But my daughter said, no, no ; the colour is very genteel ; that it 

 was my eyes that deceived me. He was a gentleman of the law, in a fine rich 



