INDEX. 
Nerve, on the function of the trigeminus, or fifth nerve, 417 
Nerve . of the Face , Respiratory, is that which is called 
portio dura of the seventh, - - 410 
— its structure, - 412 
Nerves, an account of some experiments on their structure 
and functions, which lead to a new arrangement of the 
system, - - - -398 
those of the animal frame are complex in propor- 
tion to the variety of functions which the parts have to 
maintain, - 402 
may be divided into two parts or systems ; the one 
simple and uniform, the other irregular and complex, in 
proportion to the complexity of organization, - 403 
— — - — on those of the face, - - - 40s 
— respiratory , - - - - 405 
Nervous system, intricacy of it, - - - 399 
Nigrutn pigmentum, is not necessary for vision, but only 
provided as a defence against strong light, - 5 
O 
Oil, experiments on the gas produced from it, - 149 
P 
Papyri, some observations and experiments on those found 
in the ruins of Herculaneum, - 191 
an account of some experiments made in England 
on some fragments of papyri, in 1818, - - 1 92 
on the state of those found at Herculaneum, - 194 
an account of some experiments on papyri, made in 
the Museum at Naples, - - 199 
some general observations on papyri, - 204 
Parallax, an account of observations made with the eight 
feet astronomical circle, at the Observatory of Trinity 
College, Dublin, since the beginning of the year 1818, 
for investigating the effects of parallax and aberration 
on the planes of certain fixed stars ; also the comparison 
of these with former observations for determining the 
effects of lunar nutation, - - 327 
Pendulum, an account of experiments to determine the 
times of its vibration in different latitudes, - - 163 
Perchloride of Carbon, experiments on its nature, - 49 
