40 HOPKINS: BIOCLIMATIC LAW 



maximum of 5000 feet. In these departures the earUer dates 

 and higher altitudes are the result of accelerating influences, and 

 later dates and lower altitudes are due to retarding influences. 

 In order to gather further facts and evidence on the variations 

 from the constant and also the rate of advance of the spring 

 season, as revealed by periodical phenomena, observations were 

 begun at Brownsville in southeastern Texas and at Palm Beach 

 and Miami, Florida, in February of the present year (19 19). 

 These were continued along routes from Brownsville in a general 

 northeastward direction to the northern borders of the States of 

 New York, Vermont, and Maine and to above the timberline on 

 Mount Washington, from Miami north along the Atlantic Coast 

 to Washington and from Palm Beach across the Florida Penin- 

 sula to Ft. Wayne, then north to Lake City and west to Pensacola, 

 and return to Washington by the way of Birmingham, Alabama, 

 Atlanta, Georgia, and Charlotte, North Carolina. These routes 

 involved a travel, principally by rail, by Messrs. Griffith, Craig- 

 head, Snyder, and the writer, of over 20,000 miles and the record- 

 ing of over 20,000 obserA^ations. The data accumulated by these 

 investigations has ser\^ed not only to verify the facts and evidence 

 furnished by the wheat harvest and altitude limit data but has 

 contributed information towards the solving of many other prob- 

 lems of scientific and economic interest, relating to the applica- 

 tion of the law in research and practice, which I hope to discuss 

 in future papers before this and other societies of Washington. 



