Assistant and successor to E-J. Marey, Bull was destined to have a profound influence on many branches of scientific research, and in particular on applications of spark illumination in photography and high-speed cinematography. Born on 5 January 1876 in Dublin, to a British merchant/carpenter father and French mother, a large part of his life was spent in France. His brother was the cartoonist and photographer René Bull. In 1895, through his skills as an amateur photographer, he became an assistant to, and student of, the scientist whom he described affectionately sixty years later as 'Mon Maitre Marey'. His duties included developing and printing the chronophotographic negatives. Bull, attired completely in white, was himself the subject of least one of Marey's physiological studies, jumping a hurdle. He later recalled being '... sent out into the streets of Paris, to photograph ... scenes ... with the early Chronophotographe. Marey was content to study the negatives. Selected frames were printed. Marey understood the importance of it, and we very often took negatives that had no real scientific interest at all, just to show what could be done with non-perforated film'. Marey had failed successfully to project the non-perforated filmstrips, but Bull claimed in one version of his reminiscences to have later achieved a few shaky projections when his master was not present.
When Marey died in 1904, Bull was able to concentrate on his own work, including high-speed studies of insect flight (some stereoscopic), producing a stream of research papers. He later became sub-Director of the Institut Marey, (the Director being an absent political nominee). A craftsman in wood and metal, he constructed much of his own apparatus. During the First World War he developed sound-ranging equipment - adopted by the British army - for the location of enemy gun batteries, and produced high-speed photographic analyses of ballistics. By 1924, he was able to report to the Royal Institution in London filming speeds of 100,000 images per second. His activities in acoustics, physiology and optics continued unabated, and in the 1950s he was still publishing papers on high-speed cinematography. Bull, described by his friend Stanley Bowler (one-time editor of the British Journal of Photography) as a 'tiny, bird-like, lovable figure, with an irrepressible sense of humour, and an ability to bring pleasure to those around him', received numerous honours from the French and British, and was still receiving visitors to tea in his Paris flat in 1971, aged 95. He died on 25 August 1972.