INDEX. 
L 
Landrail , its powers of flight, 15. 
Lambton, General, his observations used by Dr. Brinkley to try 
the reality of the southing of the stars, 73. 
Lead, its electro-mechanical effect in alloy with mercury, 183. 
Lecture, Bakerian, on certain motions of conducting fluids produced 
by electricity, 162. 
Linnets in the Atlantic, several hundred miles from land, 13. 
Lobster, brains of, 6, 10, Plate II. 
Longitude of Madeira (l h 7 m 39 s .O W.) determined by Dr. Tiarks 
by means of chronometers, 365. 
— errors in, as determined in the Trigonometrical Survey, 
360, 365. 
differences of , between Dover and Falmouth, 364 — be- 
tween Portsmouth and Falmouth, 364 — between Falmouth and 
Madeira, 365. 
M 
Madeira, longitude of, 365. 
Magnesia, hydrate of, deposited by sea water by the action of copper, 
152 — its carbonate similarly deposited, 244. 
Magnetism, its developement in iron and steel by percussion, 197 ; 
see percussion— augmentation of, by a regular system of ham » 
mering, 210 — distribution of in ships of war, 310. 
Magpie, anecdote illustrating the rapidity of its mateing, 21. 
Martins, dissection of, on their first appearance, 24 — desertion of 
their young by a pair, explained, 25— cause of their assembling 
on roofs, 29. 
Maskelyne, his observations on Schehallien used to try the reality 
of southern motion, 68. 
Mean of many indifferent observations of double stars preferable to 
the best single one, Part iii. 21 — remarkable instance of in Rigel, 
iii. 75. 
Measurement of a height in Spitsbergen, trigonometrical and baro- 
metrical, compared, 290 — great decrepancy in, as observed by 
Captain Sabine and Captain Phipps, on a hill in Amsterdam 
island, 306. 
of a base ; see base. 
Mercury. Herschel on the motions of when electrified under 
conducting liquids, 162— under sulphuric acid, 163 — attraction 
of globules of to the negative pole of a battery explained — a 
