An American enterprise in the same direction was that of Captain James M. Gilliss, who, in 1849, organized an astronomical expedition to Chili. The principal motive of this enterprise was the determining of the solar parallax by observations upon Venus and Mars near the time of their nearest approach to the earth. As these observations would take but a small part of his time, Gilliss determined to take with him instruments for determining the positions of the stars. He established his observatory at a point near Santiago, where he continued his observations for nearly three years. He was a practical observer, but an untoward circumstance detracted from the value of his work. His observatory was built upon a rocky eminence, a foundation which seemed to afford the best possible guarantee of the stability of his instruments. He made no attempt to reduce his observations till after his return home. Then it was found that the foundation, through the expansion and contraction due to the heat of the sun, was subject to a diurnal change which made it extremely difficult to derive good results from his careful work. It was not until 1896, more than thirty years after his death, that the catalogue of the stars observed by him was at last completed and published. We do not derogate in any way from the merit of these efforts in saying that they could not lead to results comparable with those of the score of richly equipped northern observatories which the leading nations and universities of Europe had endowed and supported for more than a hundred years. Only within the last thirty years has it been possible to bring our knowledge of the southern heavens up to a satisfactory stage. Now, however, the progress of southern astronomy, if we may use the term, is such that in several points our knowledge of the southern heavens surpasses that of the northern ones. If we measure institutions by the importance of the work they are doing, there are several in the southern hemisphere which must to-day be placed in the first rank. The history and work of the Cordova Observatory are of special interest. In 1870 Dr. B. A. Gould, who might fairly be considered as the father of modern American astronomy, conceived the idea of establishing an observatory of the first class in South America. He found the President and Governor of the Argentine Republic ready to support his scheme with a liberality well fitted to impress us with a high sense of their standard of civilization. In a year or two the observatory at Cordova was in active operation. A statement of its work belongs to a subsequent chapter. Suffice it to remark here that Dr. Gould continued in active charge until 1885, when he returned home, and was succeeded by Thome, the present director.