The organ, as we have seen, is a collection of an indefinite number of instruments.

It places before the organist extraordinary means of expressing himself.

No two of these instruments are precisely alike.

The organ is only a theme with innumerable variations, determined by the place in which it is to be installed, by the amount of money at the builder's disposal, by his inventiveness, and, often, by his personal whims.

As a result time is required for the organist to learn his instrument thoroughly.