Besides the routine of an extensive publishing business, the history of the house during this time includes a number of large undertakings involving the expenditure of vast sums of money, and years of labor by many workers, and attended with risks that only the most far-seeing business sagacity could justify. We may presume that the several members of the firm shared a common faith in the success of these great enterprises, but it is fair to infer that as the head of the house William H. Appleton took a leading part in their origin and execution. One of these ventures was the publication of the American Cyclopædia, which in its present revised form represents an outlay of over a million dollars and some ten years of time. Another undertaking, and the one that we wish more particularly to speak of here, was the extension of the business in the line of popular scientific publications. Scientific circles in this country have never realized the debt they owe to D. Appleton and Company, and especially to William H. Appleton, in this regard. It is no exaggeration to say that the advance of science in the United States was hastened by more than a quarter of a century by the enlightened and courageous policy which led the firm to add this class of books to their lists at the time they did. Everything apparently was against it--nothing in its favor. Our scientific literature consisted mainly of a few text-books having only a limited sale. Science itself was an affair of laboratories and bug collectors, the one to be shunned and the other commiserated. The few utterances of scientific men having a bearing on the great questions of the right interpretation of Nature, man's relations to his fellows and to the world at large, social betterment, etc., that here and there arrested public attention were received with contemptuous sneers or scouted as the rankest infidelity. Few who are not past middle life will find it possible now to realize that this was the general attitude toward science forty years ago, but we have only to refer the reader to the writings of the time for abundant confirmation of our statements.