September-October, 19^5 



CHICAGO NATURAL HISTORY MUSEUM BULLETIN 



Page S 



PHOTO EXHIBIT SCHEDULED 

 AT MUSEUM IN FEBRUARY 



Chicago Natural History Museum has 

 made its facilities available for the exhibi- 

 tion of photographs selected for display in 

 the First Chicago International Salon of 

 Nature Photography, under the auspices of 

 the Chicago Nature Camera Club, with the 

 participation of the Chicago Horticultural 

 Society and Garden Center. 



The exhibit will be held in Stanley Field 

 Hall, January 28 to February 28 inclusive. 



Entries may be submitted at once, and 

 all must be received by January 10 to be 

 eligible for consideration. They may be 

 addressed to the Salon in care of the 

 Museum, Roosevelt Road and Field Drive, 

 Chicago 5. The entry fee is $1, for which a 

 maximum of 4 prints and 6 color slides may 

 be submitted; checks and money orders 

 should he made payable to the Chicago Nature 

 Camera Club. The club has arranged for 

 participation by associated clubs throughout 

 this country and other nations, but member- 

 ship in one of these clubs is not a require- 

 ment of eligibility for entrants. 



Photographs and color slides in six clas- 

 sifications are desired: 



Plant life — flowers, trees, shrubs, fungi, 

 etc. (but not gardens in this division). 



Animal life — mammals, birds, insects, 

 reptiles, tracks, etc. 



Scenery — with particular emphasis on 

 geological aspects and natural phenomena. 



Gardens — especially Victory Gardens 

 and their products. 



Anthropology — ethnological and archae- 

 ological subjects; primitive man, native 

 habitations, sites of ancient cultures and 

 civilizations, etc. 



Color slides — any subjects in the fore- 

 going classifications. 



A number of accepted pictures will be 

 reproduced in the Journal of the Photographic 

 Society of America, and elsewhere. A com- 

 mittee of five judges will be named, and 

 prizes will be awarded by the Chicago 

 Nature Camera Club and the Chicago 

 Horticultural Society. 



SHANGRI-LA IN NEW GUINEA 

 FOUND YEARS AGO 



New evidence has shown that Hidden 

 Valley, supposedly discovered by the United 

 States Army Air Forces last year in the 

 mountains of central Dutch New Guinea, 

 was actually first entered by white men 

 25 years ago, and the "Shangri-la" area was 

 discovered and thoroughly explored by 

 Americans in 1938. Considerable space has 

 been devoted in the press to the marooning 

 there of a WAC and two other Army per- 

 sonnel as the result of a plane crash. 



When the first reports on this "Shangri- 

 la" were published, it was evident that it lay 

 in the region explored by the Richard 

 Archbold Expedition in 1938. This expedi- 

 tion, which was affiliated with the American 



Museum of Natural History, flew men and 

 supplies by amphibious plane to lofty Lake 

 Habbema, and from that base explored the 

 surrounding country, including a densely 

 populated valley on the Baliem or Balim 

 River. This valley was named Grand 

 Valley by the American explorers. 



The conflicting early reports on Hidden 

 Valley suggested it was distinct from Grand 

 Valley. A recent communication from Dr. 

 L. J. Brass, a member of the Archbold 

 Expedition, however, stated that compari- 

 son of the Archbold aerial photographs 

 with official Air Force photographs proves 

 conclusively that the two are the same. 



ADVENTURE SOUTH 



Special Lectures^September 



Three successive lectures on Latin 

 America are to be given in the James 

 Simpson Theatre of Chicago Natural 

 History Museum on September 13, 

 14, and 15, by the well-known lec- 

 turer, Mr. Sullivan C. Richardson. 



The lectures will be illustrated with 

 kodachrome motion pictures made by Mr. 

 Richardson on trips to Central and South 

 America. Some of his pictures were made 

 in 1940 on the occasion of a spectacular 

 trip by automobile from the Great Lakes 

 to the Straits of Magellan over the route of 

 the Pan American Highway; others during 

 Mr. Richardson's recent service with the 

 Office of Inter-American Affairs. 



His current lecture tour is made possible 

 as a public service through the courtesy of 

 the Plymouth and Dodge Divisions of the 

 Chrysler Corporation, and the Association 

 of American Colleges. 



At the conclusion of each lecture, Mr. 

 Richardson will conduct an open forum type 

 of discussion for those interested in the 

 language, history, education, and social and 

 economic problems of Latin America. 



Museum members and the general public 

 are cordially invited to attend these free 

 lectures. School teachers and students of 

 Latin American affairs will find them 

 particularly entertaining and informative. 

 Interested persons are urged to attend all 

 three lectures. Reservations must be made 

 in advance, either by postcard or by tele- 

 phone (WABash 9410). Tickets will be 

 mailed if time permits, or held in reserve at 

 the door until the time of the first lecture. 

 The series is scheduled as follows: 



September 13, 14, and 15 



Thursday evening at 8 — ADVENTURE 

 South to Cape Horn. 



Friday evening at 8— Rubber River 



Saturday afternoon at 2— Good Neigh- 

 bors AND Strategic Materials 



For the evening lectures only, entrance 

 to Simpson Theatre must be made through 

 the West Door of the Museum. 



MUSEUM DISPLAYS MINERALS 

 BASIC FOR ATOM-BOMB 



Bv PAUL O. McGREW 



ACTINO ClllEI' CURATOR, DEPARTMENT OF' GEOLOGY 



Radioactive minerals have, for many 

 years, been of great interest to physicists, 

 chemists and geologists. The announce- 

 ment of the new atomic bomb that played 

 such an important, if not decisive, role in 

 terminating World War II has brought 

 these minerals and some of their elements 

 to public attention. Although many details 

 are still unannounced, it is clear that a 

 radioactive element is the major factor in 

 the great power of the bomb. 



Among the best known radioactive 

 elements are uranium, thorium, radium 

 and actinium. All possess the rare property 

 of emitting rays that penetrate matter 

 opaque to ordinary light rays. This emis- 

 sion of rays is a result of atomic disintegra- 

 tion — a change from one element into 

 another. It is accompanied by the release 

 of tremendous amounts of energy — pre- 

 sumably the source of energy for the bomb. 

 As the parent element disintegrates, a series 

 of new elements is produced; they are 

 unstable. These in their turn break 

 down into other elements until, as one 

 end-product, lead is formed. The lead 

 thus produced from the disintegration of 

 radioactive elements has its own charac- 

 teristic atomic weights. 



For the geologist this phenomenon is 

 important because it supplies a means of 

 "dating" many rocks containing radio- 

 active minerals. Experimentation has 

 proved that the disintegration goes on at 

 a constant known rate — a rate unaffected 

 by temperature, pressure or other natural 

 forces. All of the lead formed as an end- 

 product accumulates in the parent matrix 

 or rock. Thus by measuring the amount of 

 lead and the amount of the radioactive 

 element that produced it, the time since 

 the origin of the original mineral can be 

 determined. 



This method has led to the most accurate 

 estimates of the age in years of many of the 

 earth's rocks and of the earth itself. Certain 

 rocks in Russia have been found to be 

 1,800,000,000 years old. We know that 

 the earth is at least older than this — exactly 

 how much cannot be determined. 



Because of the great interest In 

 radioactive minerals as a result of the 

 "atom bomb," a special temporary 

 case has been installed in Stanley Field 

 Hall. The exhibit shows many of the 

 minerals from which radioactive ele- 

 ments are obtained and other pertinent 

 information. 



Placed in conspicuous places on the walls 

 in Hall 8 are beautiful photographs of 

 Mayan ruins. From them may be observed 

 the conditions under which archaeologists 

 have to work. 



