SO Mr Wardrop's case of a Lady Born Blinds who 



165° 5(y. With a somewhat higher degree of precision, I 

 sometimes found the inclination of two faces over the apex = 

 150° 36', as is given above. Besides the alternation of par- 

 ticles of the individuals, the stria? may likewise be owing to 

 some additional faces, which replace the acute edges of the 

 prism, and have therefore nearly the same situation as the 

 faces of the six-sided prism. 



Zinkenite bears a high degree of resemblance to the grey 

 antimony, though it is at once distinguished from it by the 

 bright cleavage of the latter, parallel to the short diagonal of 

 a rhombic prism of about 90^°, by its lower degree of hard- 

 ness, which is equal only to 2.0, or the hardness of rock-salt, 

 and by its lower specific gravity, which, according to Mohs, 

 is only = 4.620. As to colour, hardness, and fracture, it 

 greatly resembles Bournonite, but it differs in its regular form, 

 though belonging to the same system of crystallization,' be- 

 sides some slight, yet easily perceptible shades, even in the 

 colour, which is darker in Bournonite, and approaches to 

 blackish lead-grey, while the hardness is somewhat lower, 

 only 2.5 to 3.0 of the scale of Mohs, a little below calca- 

 reous spar. 



Art. V. — On the Case of a Lady Bom Blind, who received 

 Sight at an Advanced Age by the Formation of an Artifi- 

 cial Pupil.* By James Wardrop, Esq. F. R. S. Edin. 

 Surgeon Extraordinary to the King. 



The lady, whose case forms the subject of this paper, was 

 observed, during the first months of her infancy, to have 

 something peculiar in the appearance of her eyes, and an unu- 

 sual groping manner, which made her parents suspect that 

 she had defective vision. When about six months old, she 

 was placed under the care of a Parisian oculist, who performed 

 an operation on both her eyes, with a view to afford her sight. 

 The operation on the right eye was, however, followed by 



* This Article is abridged, though very slightly, from the original Me- 

 moir, which will appear in the next part of the Philosophical Transactions. 

 —En. 



