This type of pen has a ball-bearing for a point which rolls the ink on to the paper and, with its special ink, is so constructed that it needs refilling only at long intervals. Although the idea that the writing point of a pen should consist of a revolving ball goes back much earlier, the modern form of this pen was the invention of two Hungarians, Ladislao J. Biro, who at various times had been a sculptor, painter and journalist, and his brother Georg, a chemist. The brothers conducted their original experiments in Hungary and patents were applied for in 1938. At the outbreak of war they moved to the Argentine and there, with the help of financial backers, especially H. G. Martin, a company was formed to perfect and produce the pen. In 1943 a defect in connection with the piston reservoir became apparent: ink was forced out by the piston whether the pen was being used or not. Biro and his colleagues found the solution in the provision of a ball-point in which the ball rested on a base seat intersected by feed channels and the employment of a reservoir consisting of a tube in which the ink was maintained as an uninterrupted column by capillary forces.