The Origin of Petroleum.--By O.C.D. Ross.--A further and more
lengthy discussion in regard to petroleum and theory of its
production by volcanic action.

VII. GUNNERY.--Weldon's Range Finder.--An instrument for determining
distances, with description of its use.--3 illustrations.

VIII. MECHANICAL ENGINEERING.--Mercury Weighing Machine.--A
type of weighing machine depending on the displacement
of mercury.--1 illustration.

Wheels Linked with a Bell Crank.--Curious examples of
mechanical constructions in the communication of motion
between wheels.--3 illustrations.

IX. MEDICINE AND HYGIENE.--Cold and Mortality.--By Dr. B.W.
RICHARDSON.--The effect of cold upon the operation of the
animal system, with practical rules.

On the Occurrence of Tin in Canned Food.--By H.A. WEBER.--A
very valuable and important series of analyses of American and
other food products for tin and copper.

The Treatment of Glaucoma.--Note on the treatment of this
disease fatal to vision.

X. METALLURGY.--On the Elimination of Sulphur from Pig Iron.
By J. MASSENEZ.--The desulphurization of pig iron by treatment
with manganese, with apparatus employed.--5 illustrations.