INDEX. 
M page 
Madras, observations for ascertaining the length of the 
pendulum at that place, - - 127 
Magnesia , carbonate of, its presence in sea-water not de- 
tected by the most delicate tests, - - 454 
Magnetical properties of steel and iron by percussion , - 24 1 
Marcet, Alexander, M. D. Some experiments and re- • 
searches on the saline contents of sea-water, undertaken 
with a view to correct and improve its chemical ana- 
lysis, - •■ - - 448 
Mendip Hills , account of some teeth and bones of elephants 
and other animals discovered there, in cavities of moun- 
tain lime-stone, - - - 2QQ 
Mercury , which some chemists have detected in sea-salt 
or its products, concluded to have been introduced there 
from some local or accidental circumstances, - 451 
Meyer, Professor J. Tobias, the superiority of his mag- 
netic needles shown, - - 4 
Moon, communication of a curious appearance lately ob- 
served upon it, - - 237 
Mural circle, Letter from the Astronomer Royal to Sir 
Humphry Davy, Bart. P. R. S. relative to a derange- 
ment in the mural circle at the Royal Observatory, - 86 
Muriate oj lime , not contained in sea- water, - 453 
Muscles of the trunk, of those which are brought in aid of 
the common respiratory muscles, - - 288 
N 
Nairne, Edward, Esq. his observations for determining 
the amount of the dip of the magnetic needle in London, 
in 1772, referred to, - - - - 18 
Needle, compass, a Table showing the effect which iron at 
different degrees of heat, has upon it, - - 124 
Needle, magnetic, an account of one made upon the con- 
struction of that recommended by Professor J. Tobias 
Meyer, with some variations, 4 
— - — an account of experiments to determine 
the amount of its dip in London, in August 1821, - 1 
Nerves , of those which associate the muscles of the chest, 
in the actions of breathing, speaking, and expression, 284 
eighth pair of, the influence of the voltaic battery 
in obviating the effects of their division, - 22 
