Announcement is made with deep regret of the death of Dr. Rollin A. Harris, computer/mathematician, section of tides and currents. He died suddenly of heart disease on January 20, 1918, in the 55th year of his age. He was born in Randolph, New York, on April 18, 1863.

He graduated from Cornell University in 1885, with the degree of Ph.B., and obtained the degree of Ph. D from the same institution in 1888. He was a fellow in mathematics in Cornell University, 1886-1887, and the same in Clark University, 1889-1890.

Dr. Harris entered the service of the Coast and Geodetic Survey as a computer/mathematician on July 5, 1890, through the United States Civil Service. For about 3 years thereafter his attention was given to the ordinary work of the Bureau relative to tides and currents, in which he soon became very proficient.

The need having become urgent for an officer of the Bureau to take up the matter of tidal research, in order to coordinate and improve the various methods of work which had been in use, the ability and training of Dr. Harris were turned into that channel.

He was well suited to the task, and entered into the work with such enthusiasm that between the years 1894 and 1907, he produced the Manual of Tides, containing a large amount of original contributions to our knowledge of the tides, and which when printed required about 1,200 quarto pages.

When the Tide Tables were extended to include foreign as well as domestic ports it was found that the Ferrel tide-predicting machine was not well fitted for producing many types of tides, and the matter of constructing another and improved tide machine was taken up. On account of his intimate acquaintance with tidal theory, Dr. Harris was given charge of mathematical principles of the construction of the new tide-predicting machine, which upon its completion was proved to be probably the most satisfactory machine of its kind ever constructed anywhere.

His broad knowledge upon all matters relating to tides and currents and related subjects rendered Dr. Harris of great service to this Survey and also to engineers and others who sought his advice. His removal by death has caused a loss which will long be felt.

In 1890 he married Miss Emily J. Doty, of Falconer, New York, who survives him. He is also survived by his mother, of Jamestown, New York, a brother, Dr. G. D. Harris, professor at Cornell University, and two sisters, of Jamestown, New York. He was a member f the Washington Academy of Sciences, the Washington Philosophical Society, fellow of the American Association of the Advancement of Science, and was for many years a contributor to the Annals of Mathematics and other magazines.