INDEX. 
Circle, Dublin , reasons for supposing its figure unaltered and 
readings exact, 496, 497- 
■ table of the reading of its microscopes, 492. 
— — ' Greenwich ; vide mural circle. 
Cirrhipcda , only found in tertiary formations, 415. 
Clock , with conical pendulum ; vide conical pendulum. 
used by Mr. Fallows in observations at the Cape- 
account of, 461. 
Cohesion, absolute, of steel, 358. 
Committee of R. S. appointed to consider the prevention of the 
corrosion of the copper sheathing of ships, 151. 
Conical pendulums, clocks for measuring velocity of sound with, 
427 — their rates, 441 — invented by Huygens — first made by 
Benzenberg, 427. 
Copper sheathing of ships, Sir H, Davy on preservation of, 151. 
■ pure, acted on by sea water more rapidly than if alloyed, 
151. 
» ■ ■ ■ action of sea water on, forms insoluble submuriate, 152. 
— exposed to sea water absorbs oxygen from the atmo- 
sphere, 153. 
a weakly positive metal, 154 — preserved from action of 
sea water by being weakly electrified negatively, 155 — this 
accomplished by the contact of tin, zinc, or iron, 155, 156. — 
Further experiments on, 243. 
possesses no electro-mechanical power in alloy with 
mercury, 183. 
— general use of, near the binnacles of ships recommended, 
328. 
Coulomb, his apparatus for measuring the intensity of mag- 
netism, 313. 
Croonian Lecture, on the internal structure of the human brain, 1. 
Cuckoo , migration of, 29- 
Currents, produced in electrified mercury under liquids, 162, 
et seq. 
counter, arise under various saline solutions, 172. 
Cyanogen , mixed with oxygen, not altered by platina sponge at 
ordinary temperatures, 267— mixed with oxygen and hydro- 
gen, action of the sponge on, 272.- — Apparent exception 
offered by it to the order of its influence in diminishing the 
action of the sponge, 283. 
I 
