8 HERMANN VON HELMHOLTZ 



passage of ra}^s of light through the telescope, or in learning 

 some of the optical theorems that served him in good stead 

 later on in the construction of the ophthalmoscope. 



He was more fascinated by the elements of physics as 

 taught in the Gymnasium, than by his purely geometrical and 

 algebraic studies. And when he began to follow the physical 

 and chemical experiments which Professor Meyer demonstrated 

 in the laboratory to his students, and listened to the scientific 

 discussions between his father and his mathematical colleague 

 (in which, among other matters, the question of a perpetuum 

 mobile, and the futile attempts to realize it, was continually 

 cropping up), the boy's desire to immerse himself in these 

 problems waxed stronger and stronger, and he burned to 

 enlarge his mental horizon by independent and original ex- 

 periments. It was at this time indeed (as Helmholtz often 

 attested in later days) that he conceived the idea which in- 

 creasingly dominated him, that the knowledge of natural laws 

 should give us not only a spiritual mastery over Nature, but 

 an actual material control of her processes. The vigorous 

 young scholar was consciously outgrowing the narrow circle 

 of his home and school relations. 



With no other appliances than some spectacle glasses and 

 a little botanical lens belonging to his father, young Helmholtz 

 and a friend contrived to make up optical instruments, modi- 

 fying the construction again and again until he hit off some 

 practicable arrangement. The necessary knowledge had to 

 be acquired from a few antiquated textbooks on physics and 

 chemistry possessed by his father, ' to which the discoveries 

 of Lavoisier and Humphry Davy had not yet penetrated, while 

 phlogiston still played its part and galvanism ended with the 

 voltaic pile/ 



At fifteen, Helmholtz was described by his fellow-students 

 as reserved and self-contained, showing invariable kindness 

 to those weaker than himself. As regards his studies, he was by 

 no means devoted exclusively to the exact sciences, for his first 

 school-report in the first class testifies to a fairly level interest 

 in all branches of his studies, his progress in Latin, Greek, 

 Hebrew, religious instruction, mathematics, and physics being 

 characterized as good, and history and geography as excellent : 

 while the same appears from the decision of the masters' 



