For a century after Dalton made his proposal, it remained entirely hypothetical, and a few eminent scientists—notably the Viennese physicist Ernst Mach, for whom is named the speed of sound—doubted the existence of atoms at all. "Atoms cannot be perceived by the senses... they are things of thought," he wrote. The existence of atoms was so doubtfully held in the German-speaking world in particular that it was said to have played a part in the suicide of the great theoretical physicist, and atomic enthusiast, Ludwig Boltzmann in 1906.
It was Einstein who provided the first incontrovertible evidence of atoms’ existence with his paper on Brownian motion in 1905, but this attracted little attention and in any case Einstein was soon to become consumed with his work on general relativity. So the first real hero of the atomic age, if not the first personage on the scene, was Ernest Rutherford.
Rutherford was born in 1871 in the "back blocks" of New Zealand to parents who had emigrated from Scotland to raise a little flax and a lot of children (to paraphrase Steven Weinberg). Growing up in a remote part of a remote country, he was about as far from the mainstream of science as it was possible to be, but in 1895 he won a scholarship that took him to the Cavendish Laboratory at Cambridge University, which was about to become the hottest place in the world to do physics.