Mr. ANDREW CARNEGIE.--First use of the gas.--Wells near
Pittsburg.--Extent of territory underlain with gas.--Cost of
piping.--Analyses ofnatural gas.

A Gas Engine Water Supply Alarm.--1 figure.

The Water Supply of Ancient Roman Cities.--An address by
Prof. W.H. CORFIELD.--Aqueducts for the supply of
Borne.--The aqueduct bridge Pont du Gard.--The supply of
Lyons.--Construction of underground aqueducts.

Steam Engine Economy.--By Chief Engineer J. LOWE,
U.S.N.--With diagram.

The "Elastic Limit" in Metals.--Selection of wire for
suspension bridges, etc.

Prices of Metals in 1874 and 1884.--With table.


II. TECHNOLOGY.--A Method of Measuring the Absolute Sensitiveness
of Photographic Dry Plates.--By Wm. H. PICKERING.--From the
proceedings of the Academy of Arts and Sciences.

Soldering and Repairing Platinum Vessels in the
Laboratory.--By J.W. PRATT.

The Helicoidal or Wire Stone Saw invented by M.P. GAY.--With
engraving of quarry showing application of saw, and 5 figures.