Casts of models have been made in iron; but this, while suitable perhaps for models of mounds and subjects of like character, would hardly be applicable to small scale models with fine detail; such casts require too much surface finishing. The material known as Lincrusta-Walton seems to me to be the ideal material for this purpose. It is tougher than rubber, will take the finest detail, and its surface can be treated in any way desired. Unfortunately the manufacture of models in this material would require expensive machinery, and is outside the scope of a modeling room. Should it ever become commercially advantageous, however, casts of a model of ordinary size, in every way equal to the original, can be turned out in this material at a very small cost. It remains to speak of the reproduction of models by process-engravings--a method that will probably receive much more attention in the future than it has in the past. It is perhaps along this line that the cheap reproduction of models will develop; but the subject is too large a one to be adequately treated here, and must be postponed until some future occasion. [Illustration: HACHURED AND CONTOURED MAPS. REPRESENTATION OF A HILL ACCORDING TO THE TWO SYSTEMS AND ON DIFFERENT SCALES. From Supplement to Enthoffer's Topographical Atlas by permission of Mr. Enthoffer.] [Illustration: FROM BUTLER'S COMPLETE GEOGRAPHY. COPYRIGHT, 1888, BY E. H. BUTLER & CO. Printed by permission.] NATIONAL GEOGRAPHIC SOCIETY. ABSTRACT OF MINUTES. _October 5, 1888, Ninth Meeting_. A paper was read entitled, "Topographic Models," by Mr. Cosmos Mindeleff. Published in the "National Geographic Magazine," Vol. I, No. 3. _October 19, 1888, Tenth Meeting_. The attendance being very small, no paper was read. _November 2, 1888, Eleventh Meeting_. The paper of the evening was entitled, "Surveys, their Kinds and Purposes," by Mr. Marcus Baker. The paper was discussed by Messrs. Ogden, Goodfellow, Gannett and Baker. Published in "Science," Vol. XII, No. 304. _November 16, 1888, Twelfth Meeting_. A paper was read by Mr. Henry Gannett, giving certain "Physical Statistics Relating to Massachusetts," derived from the map of that State recently prepared by the United States Geological Survey. A discussion followed which was participated in by Messrs. Baker, Kenaston, Fernow, Weed, and the author. A second paper entitled, "Something about Tornadoes," was read by Lieut. J. P. Finley, U. S. Signal Corps. _November 30, 1888, Thirteenth Meeting_. The annual reports of vice-Presidents Herbert G. Ogden and Gen. A. W. Greely were delivered. Published in the "National Geographic Magazine," Vol. I, No. 2. _December 20, 1888, Fourteenth Meeting_. Held in the Law Lecture Room of the Columbian University. The President delivered his Annual Address, entitled, "Africa." Published in the "National Geographic Magazine," Vol. I, No. 2. _December 28, 1888, Fifteenth Meeting_.