342 Dr Knox on the Comparative Andtomy of the Eye, 
In describing the mode in which the optic nerve enters the 
eye, that of birds has been more particularly attended to, with- 
out, however, neglecting the mammalia and fishes. During this 
part of the investigation, a very singular fact was discovered, 
viz. that the eye of the deer approaches in many respects to that 
of the bird, and forms the connecting link in these very diffe- 
rent classes of animals. 
The last section treats of the ciliary nerves and their distribu- 
tion; it was necessary, first, to refute the opinion recently 
adopted by some Continental anatomists, that the body which 
Dr Knox has called the Ciliary Muscle, is a nervous ganglion 
or plexus. Now, in order to refute this very erroneous notion, 
it was only required to examine the eyes of birds, of the deer, of 
any of the quadrumana, or of man himself, with due attention. 
It was evident that there exists a true nervous plexus only in 
birds, and that this plexus is situated anteriorly to the ciliary 
muscle, to which it sends numerous nerves. 
Dr Knox has entered into a few speculations relative to the 
movements of the iris, and of the nature of the ciliary nerves, and 
of the lenticular ganglion, of which we cannot pretend to give 
any account in this brief notice. It has, besides, necessarily 
happened, that, in drawing up this short abstract, numerous 
facts, tending to throw light on the physiology of the eye, have 
been omitted ; these will be found detailed in the original me- 
moir, which is published in the Transactions of the Society. 
Art. XXV. — Appendix to the Essay on the Influence of Mag- 
netism on the Rates of Chronometers,^ published in No. XIX. 
By George Harvey, Esq. F. R. S. Edin, &c. Commimi- 
cated by the Author. 
Owing to an accidental circumstance, the details of the fol- 
I'lowing experiments were omitted in the Essay on the Influence 
of Magnetism on the Rates of Chronometers, published in the 
last NumRer of the Edinburgh Philosophical Journal; and I 
should therefore feel obliged by their being added to it, as sup- 
plementary observations. 
The time-keeper F, having a detached rate of -f 2".0, was 
placed on the centre of the circular magnetic plate alluded to in 
