All during his life he retained an unusual faculty for concentrating his attention, which at times amounted to complete abstraction from his surroundings. It is related that, one cold morning his students at the University of Pavia found him in his shirt sleeves, so intent on arranging the experiments that were to illustrate his morning lecture that he was unconscious of the time, and even did not notice their coming into the room until they had been for some time in their seats and he had finally completed the arrangement for the demonstrations. He was constantly occupied with problems in natural science, looking for the explanation of phenomena that he did not understand as well as gathering new data by observation and experiment. He was gifted with the supremely inquisitive spirit, in the scientific sense of the epithet, and could not be satisfied with accepting things as he found them without knowing the reasons for them. Volta furnishes another excellent illustration of how soon genius gets at its life-work. We have his own authority for the fact that he had come to certain conclusions with regard to the explanation of electrical phenomena, which, when he was only nineteen years of age, he set forth in a letter to the Abbé Nollet, who was then one of the best known experimenters and writers on electrical phenomena in Europe. Though so young, Volta had tried to simplify Franklin's theory of electricity by assuming that there was an action only between a (supposed) electrical substance and matter. It is curious to see how much he anticipated what was to be the thinking for more than a century after his time and practically down to the present day. He considers that all bodies, in their normal state, contain electricity in such proportion that electrical equilibrium is established within them. Electrical phenomena, then, are due to disturbances of this equilibrium. Such disturbances may be produced by physical means, as by friction or by chemical means, and even atmospheric electricity may be explained in the former way.