Chapter IX: TECHNOLOGY.--Ammonia.--The manufacture of ammoniacal

gas for technical uses.--Full details of its production.

Musical Instruments.--Their construction and capabilities.--By
A.J. HIPKINS.--Second installment of this highly interesting
series of lectures treating of different kinds of instruments.

Note on Refrigerating Apparatus.

Sheet Glass from Molten Metal.--The method of making sheets
of glass from the molten material and manufacture of metal plates
by the same method.