Pioneers in Diffusion

Our modern ideas on diffusion are largely due to two men, Thomas Graham and Adolf Pick. Graham was the elder. Born on December 20, 1805, Graham was the 

Graham also performed important experiments on liquid diffusion using the equipment shown in Fig. 2.1-2 (Graham, 1850) in these experiments, he worked with dilute solutions. In one series of experiments, he connected two bottles that contained solutions at different concentrations he waited several days and then separated the bottles and analyzed their contents. In another series of experiments, he plaeed a small bottle containing a solution of known concentration in a larger jar eontaining only water. After waiting several days, he removed the bottle and analyzed its contents. 

Graham s results were simple and definitive. He showed that diffusion in liquids was at least several thousand times slower than diffusion in gases. He recognized that the diffusion process got still slower as the experiment progressed, that diffusion must 

Weight percent of sodium chloride Relative flux 

In the spring of 1847, Pick went to Marburg, where he was occasionally tutored by Carl Ludwig. Ludwig strongly believed that medicine, and indeed life itself, must have a basis in mathematics, physics, and chemistry. This attitude must have been especially appealing to Pick, who saw the chance to combine his real love, mathematics, with his chosen profession, medicine. 

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