Chapter XV

.--WIND INSTRUMENTS.

Longitudinal vibration--Columns of air--Resonance of columns of air--Length and tone--The open pipe--The overtones of an open pipe--Where overtones are used--The arrangement of the pipes and pedals--Separate sound-boards--Varieties of stops--Tuning pipes and reeds--The bellows--Electric and pneumatic

## actions--The largest organ in the world--Human reeds 287

## Chapter XVI .--TALKING-MACHINES.

The phonograph--The recorder--The reproducer--The gramophone--The making of records--Cylinder records--Gramophone records 310

##