44 
SIR DAVID BREWSTER ON THE ANATOMICAL AND OPTICAL 
divergence was greater on one side of the lens than on the other, in both lenses ; and 
in one it was so small as to show very nearly the structure in figg. 1 and 2. 
In the lenses of other whales, one of which was thirty-five feet long, I found the 
structure shown in figg. 1, 2, 3, and 4, in which there are four radiations of fibres, or 
vortices, as I believe Leeuwenhoek calls them, on each surface of the lens ; but I 
have found in one lens a spurious structure, in which there are Jive * radiations on 
one face and three on the other face of the lens. 
When the lens of the whale has been preserved in spirits, the coats have often a 
brilliant pearly lustre, a phenomenon which I have seen with equal beauty in the 
lenses of some quadrupeds, especially in that of the tiger. The fibres of the lens of 
the whale are extremely distinct, and the teeth upon them, which are visible with 
high powers, resemble those in the fibres of quadrupeds. 
The crystalline lens of the elephant possesses many remarkable peculiarities. The 
following are the dimensions of the eyeball of an elephant, which Mr. George 
Swinton was so kind as to send me from Bengal. 
Eyeball. 
Inches. 
Longest diameter 1*82 
Shortest diameter . . . . . . . . 1*10 
Cornea. 
Longest diameter . . 1*35 
Shortest diameter 0*92 
Crystalline Lens. 
Longest diameter 0*700 
Shortest diameter 0*62/ 
Thickness 0*400 
Ratio of the two diameters, 1 to 1*1 125. 
In another eye the dimensions of the lens were as follow : 
Crystalline Lens. 
Longest diameter 
Shortest diameter 
Thickness 
Inch. 
0*784 
0*700 
0*450 
Ratio of the two diameters, 1 to 1*1 1(5. 
L t- rwENHOKK says that there are five septa in the lens of the whale ; but I have not his paper beside me 
im nr ! r i > ascertain whether he means by this five radii inclined 72° to each other, or five radiations such as I 
I, -iV' t uiiid in the spurious structure here mentioned. 
