Beside the annual tide and the limited oscillation, the lake has been found to exhibit a third change, and this third or _abnormal_ change seems to be connected with the increase of the tributary streams. In order to exhibit it, it will be necessary to discuss somewhat fully the history of the rise and fall of the lake, and I shall take occasion at the same time to call attention to the preparations that have recently been made for future observations. Previous to the year 1875 no definite record was made. In 1874 Prof. Joseph Henry, secretary of the Smithsonian Institution, began a correspondence with Dr. John R. Park, of Salt Lake City, in regard to the fluctuations and other peculiarities of the lake, and as a chief result a systematic record was begun. With the coöperation of Mr. J. L. Barfoot and other citizens of Utah, Dr. Park erected a graduated pillar at Black Rock, a point on the southern shore which was then a popular summer resort. It consisted of a granite block cut in the form of an obelisk and engraved on one side with a scale of feet and inches. It was set in gravel beneath shallow water, with the zero of its scale near the surface. The water level was read on the pillar by Mr. John T. Mitchell at frequent intervals from September 14, 1875, to October 9, 1876, when the locality ceased to be used as a watering place, and the systematic record was discontinued. Two observations were made by the writer in 1877, and it was found in making the second that the shifting gravel of the beach had buried the column so deeply as to conceal half the graduation. Dr. Park has kindly furnished me a copy of Mr. Mitchell’s record. The observer was instructed to choose such times of observation that the influence of wind storms upon the level of the lake would be eliminated, and the work appears to have been faithfully performed. _Record of the height of Great Salt Lake above the zero of the granite pillar at Black Rock._