“ In addition, taking advantage of the accuracy with which the bolometer can determine the position of a source of heat by which it is affected, he mapped out in this infra-red spectrum over 700 dark lines or bands resembling the Fraunhofer lines of the visible spectrum, with a probable accuracy equal to that of refined astronomical observations. In aeronautics he succeeded in demonstrating the practicability of mechanical flight. ”

“ Later in the same year, on the 28th of November, a similar aerodrome flew about three-quarters of a mile, attaining a speed of 30 m. an hour. In 1903 he experimented with an aerodrome capable of carrying a man, but repeated accidents prevented it from being launched, and finally through lack of funds the experiments had to be abandoned without the machine ever having been free in the air (see also Flight and Flying) . ”