The SECOND SERIES of the Journal, as already stated, began with January, 1846. Up to this time the publication had been a quarterly or two volumes annually of two numbers each. From 1846 until the completion of an additional fifty volumes in 1871, the Journal was made a bimonthly, each of the two yearly volumes having three numbers each. Furthermore, a general index was given for each period of five years, that is for every ten volumes. [Illustration: Edward S. Dana] Much more important than this change was the addition to the editorial staff of James Dwight Dana, Silliman’s son-in-law. Dana returned from the four-years cruise of the Wilkes Exploring Expedition in 1842; he settled in New Haven, was married in 1844, and in 1850 was appointed Silliman professor of Geology in Yale College. He was at this time actively engaged in writing his three quarto reports for the Expedition and hence did not begin his active professional duties in Yale College until 1856. Part of his inaugural address was quoted on an earlier page. Dana had already performed the severe labor of preparing the complete index to the First Series, a volume of about 350 pages, finally issued in 1847. From the beginning of the Second Series he was closely associated with his brother-in-law, the younger Silliman. Later the editorial labor devolved more and more upon him and the larger part of this he carried until about 1890. His work, was, however, somewhat interrupted during periods of ill health. This was conspicuously true during a year’s absence in Europe in 1859–60, made necessary in the search for health; during these periods the editorial responsibility rested entirely upon the younger Silliman. Of Dana’s contributions to science in general this is not the place to speak, nor is the present writer the one to dwell in detail upon his work for the Journal. This subject is to such an extent involved in the history of geology and zoology, the subjects of several succeeding chapters, that it is adequately presented in them. It may, however, be worth stating that in the bibliography accompanying the obituary notice of Dana (=49=, 329–356, 1895) some 250 titles of articles in the Journal are enumerated; these aggregate approximately 2800 pages. The number of critical notes, abstracts, book reviews, etc., could be also given, were it worth while, but what is much more significant in this connection, than their number or aggregate length, is the fact that these notices are in a large number of cases—like those of Gray in botany—minutely critical and original in matter. They thus give the writer’s own opinion on a multitude of different subjects. It was a great benefit to Dana, as it was to science also, that he had this prompt means at hand of putting before the public the results of his active brain, which continued to work unceasingly even in times of health prostration.