Chapter III: PHYSICS AND PHYSICAL APPARATUS.--Seyfferth's Pyrometer

7 figures.--Pyrometer with electric indicator.--Method of
mounting by means of a cone on vacuum apparatus.--Mounting by
means of a sleeve.--Mounting by means of a thread on a tube.--
Mounting by means of a clasp in reservoirs.--The pyrometer
mounted on a bone-black furnace.--Mounted on a brick furnace

Delicate Scientific Instruments. By EDGAR L. LARKIN. An
interesting description of the more powerful and delicate
instruments of research used by modern scientists and their
marvelous results

The Future Development of Electrical Appliances. Lecture by
Prof. J. W. PERRY before the London Society of Arts.--Methods
and units of electrical measurements

Researches on the Radiant Matter of Crookes and the Mechanical
Theory of Electricity. By Dr. W. F. GINTL

Economy of the Electric Light. W. H. PREECE'S Experiments
Investigations

On the Space Protected by a Lightning Conductor. By WM. H.
PREECE.--5 figures

Photo-Electricity of Fluor Spar Crystals

The Aurora Borealis and Telegraph Cables

The Photographic Image: What It Is. By T. H. MORTON.
1 figure.--Section of sensitive plate after exposure and during
development

Gelatine Transparencies for the Lantern

An Integrating Machine. By C. V. BOYS.--1 figure

Upon a Modification of Wheatstone's Microphone and its
Applicability to Radiophonic Researches.
By ALEX. GRAHAM BELL,--2 figures