This innovation increased watches' accuracy enormously, reducing error from perhaps several hours per day resulting in the addition of the minute hand to the face from around 1680 in Britain and 1700 in France.
Drawing of one of his first balance springs, attached to a balance wheel, by Christiaan Huygens, published in his letter in the Journal des Sçavants of 25 February 1675.
The application of the spiral balance spring (spiral hairspring) for watches ushered in a new era of accuracy for portable timekeepers, similar to that which the pendulum had introduced for clocks.
A great leap forward in accuracy occurred in 1657 with the addition of the balance spring to the balance wheel, an invention disputed both at the time and ever since between Robert Hooke and Christiaan Huygens.
Although there was an attempt to modernise clock manufacture with mass production techniques and the application of duplicating tools and machinery by the British Watch Company in 1843, it was in the United States that this system took off.
Aaron Lufkin Dennison started a factory in 1851 in Massachusetts that used interchangeable parts, and by 1861 it was running a successful enterprise incorporated as the Waltham Watch Company.