Page "John Arnold" Paragraph 27

Even though he produced a number of pocket timekeepers, from around 1772-1778, Arnold was still experimenting with different types of compensation balance and methods of balance spring adjustment.

The most difficult problem to surmount was the problem of making an effective and continuously adjustable temperature compensation device.

For technical reasons, the temperature compensation for the balance spring had somehow to be incorporated into the balance itself and not act on the balance spring directly as had been done previously by Arnold and others.