"Chemistry at that time was exciting great interest, and Dr. Beck's courses of chemical lectures, conducted every winter in the lecture room of the academy, were attended not only by the students, but by all that was most intelligent and fashionable in the city. Henry ... was then Dr. Beck's chemical assistant, and already an admirable experimentalist, and he availed himself to the utmost of the advantages thus afforded of prosecuting his investigations in chemistry, electricity, and galvanism." Dr. T. Romeyn Beck, the principal, had become interested in the studious young man, and, when he left the academy, recommended him to one of the trustees, General Stephen Van Rensselaer, as a private tutor to his sons. Young Henry's services were engaged, and, as his teaching required but about three hours each day, he devoted his leisure to higher mathematics, in conjunction with chemistry, physiology, and anatomy, as he had decided to become a physician. In his mathematical studies he went so far as to read the _Mécanique Analytique_ of La Grange. His delicate constitution seemed unable to bear the continued strain of study and teaching, and at twenty-six, through the friendship of an influential judge, Henry received the appointment of engineer in the survey of a road between the Hudson River and Lake Erie, a distance of about three hundred miles. This gave him out-of-door life, which he needed, and, though much of his work was done in winter, in deep snow, making his way through dense forests, he entirely regained his health, and gave such excellent satisfaction that he was asked to construct a canal in Ohio, and assist in a mining enterprise in Mexico. Both of these he refused, accepting the chair of Mathematics and Natural Philosophy in the Albany Academy, at the urgent solicitation of his friend, Dr. Beck. Elected in the spring, and not entering upon his work till autumn, he spent the intervening months in geological exploration in New York State. Every hour was occupied. He had commenced solid study in earnest, as he had told the members of the "Rostrum" he should do. Having entered upon his profession, he taught mathematics seven hours daily. But he found time to make experiments in natural philosophy. The first paper which he brought before the Albany Institute was, "On the Chemical and Mechanical Effects of Steam: with Experiments designed to illustrate the Great Reduction of Temperature in Steam of High Elasticity when suddenly expanded."