INDEX. 
Electricity, its distribution in its passage through conducting 
liquids,, 168 — its course along solids assimilated to that of a gas 
through a pipe more or less obstructed, 168, note, — Delicate 
test of its developement in small quantities, 169. 
Electro -mechanical properties of metals., bear a relation to their 
electro-positive energies, 184. 
— forces : their intensity, how measured — exceed 
gravity in an enormous ratio, 184, 185. 
Ellipsoid, the figure necessary for the equilibrium of a revolving 
fluid, 131. 
attraction of, a general expression for, 138. 
two such figures satisfy the condition of equilibrium of a 
fluid revolving in a given time, 142. 
Ellipticity of the earth, formula for its determination from a sphe- 
roidical triangle of which four parts are given, 369. 
Equatorial instrument, description of a 5-feet one belonging to 
Mr. South, Part iii. 4 — ditto of a 7-feet ditto, iii. 12. 
Equilibrium of a revolving fluid mass , Ivory on the, 85— condi- 
tions necessary to insure, 98, 99 — general equations of, 101— • 
equation expressing an essential condition of, (A), 123— incom- 
patible with a rotatory velocity exceeding a certain limit, 142— 
the usual condition insufficient for its determination, 144— ano- 
ther added, 118. 
Explosive mixtures of oxygen and hydrogen, action of finely divided 
platina on, 267 -effects of other gases in mixture with, 273. 
Eyes, single vision with two, explained, 229— on the apparent 
direction of, in a portrait, 247. 
F 
Fairhaven , in Spitzbergen, chart of the harbour of, 291 — Phipps’s 
chart of by d’ Auvergne inaccurate, 290. 
Fallows, The Rev. Fearon, M. A. F. R. S., his catalogue of 
nearly all the principal stars between the Zenith of Cape Town 
and the South Pole, reduced to January 1st, 1824, 457. 
Fieldfare, a migrating bird, 35 — never breeds here, 32 — its food 
insects, 33. 
Figure of the earth ; vide earth. Of fluid masses in equilibrio ; vide 
fluid and equilibrium. 
Fishes, their optic nerves observed to cross at their points of union, 
224. 
Flexure of steel bars, how measured, 355 — phenomena of, 357, 358, 
mdcccxxiv. C 
