157 



cycle of seasonal fluctuations more or less approximates year 

 after year, and not a few of the important environing factors 

 are operative in much the same way upon by far the larger 

 part of the biological area. There is thus a common basis 

 upon which the other less constant factors produce their effect. 

 The best justification, however, for the use of the term lies in 

 the results of our work, which show a biological assemblage 

 adapted to this complex environment, and exhibiting in some 

 of its phases at least as much uniformity as the more stable 

 factors of its surroundings. 



During 1894 and the early part of 1895 readings were re- 

 corded only at occasional intervals owing to the fact that the 

 Station was occupied but part of the time, its work being as yet 

 in the preliminary stage. From August to October, 1895, bi- 

 daily readings were made by Mr. Newberry at a gage located 

 by us at our field headquarters and based upon the government 

 gage on the protection at the wagon-bridge at Havana. From 

 October, 1895, to January, 1896, the readings were taken by 

 Mr. Hempel at the government gage, and since that time bi- 

 daily or daily readings have been taken under the direction of 

 the city authorities of Havana. These readings are given in 

 the tables which follow. 



