28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. ']'J 



in age, was visited and examined in detail. Flakes of obsidian such 

 as are found in abundance throughout this area v^^ere noted but no 

 ancient artifacts or other evidence of Pleistocene man were found. 



Some time was devoted to a study of ore deposits of the region 

 including those of the historic old camps of Candelaria and Aurora 

 and also those more recent. The mercury deposits of the Pilot Moun- 

 tains were studied in some detail and interesting collections made. 

 The quadrangle is' unusually rich in minerals and much material was 

 collected for study. This came largely from the mines and prospects 

 of the region, but some unusually fine material was also recovered 

 from the muds of the " playa " lakes. 



FIELD-WORK OF THE ASTROPHYSICAL OBSERVATORY IN 

 CHILE, ARIZONA, AND CALIFORNIA 



The Astrophysical Observatory continued its work on the sun's 

 heat and the variations of it. More and more interest is being 

 expressed in this work because it promises to be a basis for advances 

 in weather forecasting. At first sight, the problem is very simple. 

 As the temperature and rainfall of the earth depend on the sun's heat, 

 a change in the sun's heat must modify temperature and rainfall. 

 Actually, however, the efifects are highly involved. 



To explain the matter briefly, there are always certain regions of 

 high and others of low barometric pressure. These are centers of 

 atmospheric circulation. The word circulation is indeed more expres- 

 sive than we often think, for the wind directions bend around these 

 centers of circulation. Meteorologists speak of cyclones and anti- 

 cyclones, meaning the great rotary tendencies of the winds over areas 

 hundreds of miles in diameter, associated respectively with barometric 

 lows and highs. Such being the case it depends at least partly on the 

 observer's position, relative to one of these atmospheric centers of 

 circulation, whether his weather is warm or cold. For winds from 

 warmer latitudes tend to make warm weather, and winds from colder 

 ones cold weather. 



If, now, the efifect of increase of the solar heating acting upon the 

 highly complex surface of the earth, with its mountains, deserts, 

 oceans, etc., should tend to displace an atmospheric action center 

 (toward the pole, for instance) a station which previously received 

 prevailingly tropical winds might afterwards receive prevailingly polar 

 winds, and thereby be cooled, not zvarmed, by the supposed increase 

 of solar heat. Another station, a few hundred miles away, might 

 experience the very opposite efifect from the same cause. 



