Special
Exhibits

MINERALS AND GEMS *

HERBERT P. WHITLOCK, Curator

To answer the question “What is a Mineral?" one side of a large A-case in the Morgan Hall of Minerals has been utilized for the display of a series of twelve group labels. Taken in order, these illustrate, by diagrams and annotated specimens, the extent of the portion of the earth's crust from which we derive our knowledge of its constituents; the proportion of the elements distributed throughout this zone of rocks in the form of minerals; the minerals exhibited in a piece of common granite; the elements which combine to form these, and their relations as constituting mineral groups; how a mineral specimen differs from a rock; what constitutes a mineral vein and how it is formed, and what part water plays in the formation of minerals.

A similar series, in course of preparation, has for its purpose the demonstration of the grouping of particles of matter to form crystals. Both of these exhibits are treated in a popular way, calculated to appeal to the average visitor.

During the year, the Department has contributed two illustrated lectures to the course prepared under the auspices of the Yonkers Board of Education. These were delivered by the Curator, the subjects being "The Water in the Atmosphere" and "Terrestrial Water and Its Work in Forming and Transforming Earth Matter."

Extension
Work

The Department has recently been able to add to its negatives available for lantern slides a series showing the methods of polishing diamonds.

* Under the Department of Mineralogy (see also pages 212 to 214).

The research laboratory is now equipped with a Goldschmidt Two-circle Goniometer for measuring crystal angles, and the initial work with this instrument has Research and already demonstrated that there is a considerable amount of material in the Bement Collection which, subjected to crystallographic study, will yield new forms.

Publication

Work on the list of new crystal forms of minerals has been completed. In addition, the Curator has published during the year "A Model for Demonstrating Crystal Structure,” American Journal of Science, XLIX, pages 259-264, and "The Percentage of Accuracy in Cutting Semi-Precious Stones," The Jewelers' Circular, February 4, 1920.

The year has been a notable one with regard to the number and value of the specimens which have been added to the collections through gifts. From a point of view of Accessions scientific interest, by far the most important of these gifts consists of a suite of 68 mounts, received through Dr. George F. Kunz from Professor Alfred Lacroix, of the Muséum d'Histoire Naturelle, Paris. These are practically all type specimens of the material described by Professor Lacroix in his monumental work on the Mineralogy of France and Her Colonies, and they include 18 species and varieties hitherto unrepresented in our collections. The Department has also acquired, through the gifts of Mr. Harry F. Guggenheim and Mr. H. C. Bellinger, excellent series of Chilean and Bolivian minerals, including tin and tungsten ore minerals from Caracoles, Bolivia, and Rancagua, Chile; also a beautiful and highly interesting series of 25 specimens of the sulphate minerals of Chuquicamata, Chile. Many of these latter are beautifully crystallized. Dr. Henry Buttgenbach, of Brussels, has presented a specimen of the new lead-manganese oxide Cesárolite from Tunis, which was discovered by him and named after Professor G. Cesáro, of Liège, Belgium. Mr. C. J. Osman has donated a finely crystallized specimen of the rare mineral Inoyite from Hillsborough, New Brunswick, a new locality for this species, which was hitherto unrepresented in the collections. The New York Mineralogical Club has presented a

large and handsome crystal of Hornblende from Hardystonville, N. J.

Among the notable additions to the Gem Collection should be mentioned a ball, ten centimeters in diameter, carved from a flawless rock crystal, and mounted on a bronze elephant of Hindoo workmanship, the gift of Messrs. Sydney and Victor D. Bevin. Through the gift of Mr. M. L. Morgenthau, this collection has also acquired a magnificent light blue Japanese Topaz, cut egg-shaped and covered with facets, weighing 1,463 carats. This is the largest cut topaz in our collection. A fine specimen of fire opal replacing wood, from Humboldt County, Nevada, was given by Mrs. W. H. Bliss; and a large and handsome example of Mediterranean coral surmounted by a figure carved from calcareous lava was presented by Commendatore Bartolomeo Mazza, through Dr. George F. Kunz.

EXISTING INVERTEBRATES *

HENRY EDWARD CRAMPTON, Curator

In the latter part of May, Curator Crampton left for a trip of several months through the South Seas and the Far East.

Field
Work

Letters and reports recently received indicate that by November he had successfully completed the first stages of his journey. Two months were spent in Guam and Saipan, of the Mariana Island Group, where Professor Crampton made general collections of invertebrates and continued his studies on the land mollusks of the genus Partula, which he has pursued in the Society Islands for several years past. He next stopped at Manila, and after two weeks in Luzon, proceeded to Hongkong and Canton, China. Here he delivered a series of lectures at the Canton Christian College. Early in October he arrived at Bangkok, Siam, whence he journeyed five hundred miles northward to Chieng-mai, the principal city of northern Siam. Here he was entertained by the Viceroy of that region, Prince Bovaradej, and had excellent opportunities to study the highly developed Lao people. Several days were spent in collecting in the elevated forests of the neighboring mountains, and early in November he was about to start for the Malay Peninsula and Java. Thence he planned to return home by way of Australia and the Samoan Islands, reaching New York about the middle of February. Professor Crampton writes:

"The contacts that have been established with many men, and several institutions, out here, will prove valuable for the enrichment of our departmental series. The authorities have been most helpful in all places. Various lots of material have been shipped back from time to time, including the Mariana Islands collections, which were the most complete."

One shipment of these collections has been received.

Under the Department of Invertebrate Zoology (see also pages 215 to 218).

During the summer, Dr. Lutz continued his important entomological survey of the region west of the one hundredth meridian, chiefly in the Red Desert and Jackson Hole regions of Wyoming. Collections were also made in Colorado, Idaho, Utah and Indiana, practically completing the survey as planned for Colorado and its immediate borders. The many specimens resulting from the trip have been mounted and for the most part identified, while reports on the insects of the Southern Rockies are in course of preparation. Mr. Watson's field work in Jamaica, mentioned in last year's report, was completed as planned, and the liberality of Mr. B. Preston Clark will make it possible to continue this phase of the West Indian work in Haiti, possibly during the winter of 1921-1922. Mr. Miner's field work during the year has been confined to local collecting, especially in Southern New Jersey, where, with the coöperation of Mr. Frank J. Myers, studies are being made of rotifers for the proposed Rotifer Group.

Darwin
Hall

The new Bryozoa Group, which was practically completed during 1919, was installed early in the year and placed on exhibition the latter part of February. This exhibit, prepared by Messrs. Herman O. Mueller, Show Shimotori and Chris E. Olsen, under Mr. Miner's direction, represents two square inches of sea bottom, magnified twenty-five diameters, or more than 15,000 times. It depicts the rich abundance and diversity of the minute animals and plants of the sea bottom.

An exhibit was also installed illustrating the distribution and variation of the land mollusk Partula, as exemplified in the Pacific island, Tahiti, of the Society Group. The mollusks of this genus are abundant in the numerous valleys of the Island, where, through isolation, varieties peculiar to certain areas have been evolved. The exhibit consists of a large relief map of Tahiti, with mollusk specimens representing the range of variation, displayed in their appropriate valleys. Two stages in the subsidence of volcanic islands and the evolution of the coral atoll, according to Darwin, are also illustrated by this relief map, in connection with a second, modeled to show the islands of Raiatea and Tahaa, also of the Society Group. The