292 GREAT MEN OF SCIENCE 



impression, as a result of his occasional remarks, that he 

 read little of importance from recent times, and perhaps only 

 kept himself informed by reports from technical journals. 

 He also laid no claim to be regarded as an example of a 

 learned man, but was, like Robert Mayer, the rare man of 

 practical occupation, who sacrificed leisure and the richer 

 enjoyment of life, or perhaps found the latter, in striving to 

 come closer to the secrets of nature. 



Hermann Helmholtz was the eldest son of a school teacher 

 in Potsdam; he attended the school and gymnasium there, 

 and then studied medicine in the Friedrich Wilhelm Institute 

 in Berlin.^ The means of his parents did not seem to allow of 

 his studying pure science, whereas in the institute in question 

 future military doctors were trained for low fees after passing 

 as entrance examination. From 1843 to 1848 he was an army 

 doctor in Potsdam, in which time he also passed his state 

 examination in medicine. At the same time, he joined 

 the new Berlin Physical Society, and soon became an ab- 

 stractor to it. The manifold studies in literature, which he 

 carried on at that time, also included fundamental mathe- 

 matical work. He was also occupied with independent 

 physiological investigations. At that time the physiologists 

 and chemists were particularly interested in the question of 

 the existence or non-existence of 'life force' and this formed 

 the subject of Helmholtz's studies. 



It was this that led to his publication in the year 1847 of a 

 paper on the conservation of force, in which he carried the 

 energy principle already founded by Robert Mayer and 

 Joule, through all domains of physics, in parts going further 

 than Mayer, and also stating it in mathematical form. In 

 particular, we there have as a new discovery the fact that 

 Faraday's law of induction likewise agrees with the 



1 For biographical details of Helmholtz see Tyndall's introduction to 

 Helmholtz's Popular Lectures on Scientific Subjects, London, 1893. 



