Dollond first disputed this possibility (Phil. Trans., 1753), but subsequently, after the Swedish physicist, Samuel Klingenstierna (1698–1765), had pointed out that Newton's law of dispersion did not harmonize with certain observed facts, Dollond began experiments to settle the question.

Hi Jonas
I thought that you would be interested to know that it was one of your fellow countrymen physists that set Dolland on the right track towards his project's success.

Rob.