346 FHILOSOPHICAL TRANSACTIONS. [aNNO 1794. 



ments as were best adapted for that purpose. Knowing that in all violent deaths 

 the muscles contract, I supposed the crystalline humour, if muscular, would 

 show signs of this effect; for which purpose I got the eyes of bullocks when 

 removed from the sockets, the moment the animal was knocked down, and while 

 the eyes were warm the humours were removed." 



Mr. Hunter had proceeded thus far in the account of his experiments, when 

 he was suddenly, and very unexpectedly, carried off; and as he has left no notes 

 on this subject, I am unable to make any addition to the account I have already 

 given. Mr. H.'s laying claim to the discovery of a fibrous structure in the crys- 

 talline humour, which had been observed long before, and described by the ac- 

 curate Leuwenhoek, may appear to require some explanation. The discovery of 

 a fibrous appearance in that humour, appertains to Leuwenhoek; but the dis- 

 covery of an eye in which this structure of the crystalline humour was perfectly 

 distinct, and in which all the circumstances, of course and situation, could be 

 determined, is due to Mr. Hunter: and if it should be found by future observa- 

 tion and experiments, that this structure, which is different from any that has 

 hitherto been described, is capable of producing consequent actions and effects, 

 sufficient to explain the adjustment of the eye to different distances, it will not 

 be considered as a small, or unimportant discovery. 



Fig. 2, pi. 4, is a transverse section of the crystalline humour of the eye of 

 a cuttle-fish, to show its structure; the central part is transparent, but the 

 others are opaque, having been coagulated by proof spirits; and give the ap- 

 pearance of distinct fibres surrounding the central part. These fibres are not 

 uniform circles or ovals, since the layers are of different thicknesses in particular 

 parts; aa the fibres where they are most numerous; bb where they are least so. 



Fig. 3, a section of the crystalline humour, the central part being removed, 

 to show the fibrous structure of the surrounding laminae. 



Jf^. Observations of a Quintuple Belt on the Planet Saturn. By JVm. Herschel, 



LL.D., F.R.S. p. 28. 



Every analogy that can be traced in the appearance of the planets, seems to 

 throw some additional light on what we know of them already. In some of my 

 former papers I have established the spheroidical form of the planet Saturn, and 

 pointed out the motion of a spot on its disc. From the first of these may be in- 

 ferred a considerable rotation on its axis; while the latter goes a step farther, and 

 shows that it has such a motion. My late observations seem to hint to us, that 

 the period in which it revolves is probably not of a long duration. They are as 

 follows: Nov. 11, 1793, S*' 35'".7-feet reflector, power 287: Close to the ring 

 of Saturn, where it passes across the body of the planet, is the shadow of the 

 ring; very narrow, and black. See fig. 4, pi. 4. Immediately south of the 



