THE FALL OF THE OLD EMPIRE. 449 
In 540 A. D. (approximately 9.18.10.0.0 according to the writer’s corre- 
lation of Maya and Christian chronology), a return of the rainier conditions 
of the preceding century was experienced and building operations were 
again checked. This did not last long, however, and in the latter half of the 
century, after Copan had been abandoned, drier conditions returned for a 
brief period, during which time the last monuments in the Old Empire were 
erected (10.1.0.0.0 to 10.2.0.0.0). 
Finally, after the first decade of the seventh century, the climate rapidly 
became much worse even than it is to-day; the dry season became so short 
that the bushes could not be burned, and thus it became impossible to prac- 
tice the only system of agriculture with which the Maya were familiar, 7. ¢., 
felling the bush at the end of the rainy season and burning it when dry. 
Disease became more prevalent, the climate more enervating, and finally, in 
despair, the Maya abandoned the country and sought new homes elsewhere. 
Huntington, as mentioned above, bases his hypothesis upon data 
derived from the Sequoia washingtoniana of California, and finds his best 
agreements with the correlation of Maya and Christian chronology proposed 
by the writer (see Appendix IT). 
The principal objection to this hypothesis is that periods of increased 
rainfall in southern California may not have been accompanied by periods 
of diminished rainfall and more favorable agricultural and general living 
conditions in the region occupied by the Maya during the Old Empire. 
Huntington’s postulate, that the climatic changes, which seem fairly 
well established for southern California, were coincident with diametrically 
opposed climatic changes in the southern Maya field, 4,000 kilometers dis- 
tant to the southeast, is a very doubtful assumption, and one by no means 
established by his California data. Indeed, precisely here lies the weakness 
of his entire hypothesis, for if it could be proved that periods of increased 
rainfall in southern California were actually accompanied by corresponding 
periods of diminished rainfall in the southern Maya field, and to the extent 
which he claims, his whole argument would be very greatly strengthened, 
since the agreements between the chronologic data established by the Sequoia 
washingtoniana and the dates of the Old Empire cities in the writer’s cor- 
relation of Maya and Christian chronology are, to say the least, striking. 
The recent meteorological investigations of Arctowski, of Brooks, of 
Helland-Hansen and Nansen, of Hilderbrandsson, and of Penck, it must be 
admitted, tend somewhat to support Huntington’s basic assumption that 
opposite climatic conditions are frequently found simultaneously in regions 
no farther apart than those here under consideration. Says Hilderbrandsson 
in this connection: 
“Tn winter the course of the meteorological elements over the part of the ocean 
lying between Iceland and Norway agrees with that which occurs over the north 
of Europe, but is in opposition to the course of the same elements over the sub- 
tropical region, the Azores to the Mediterranean.” 
1 Hilderbrandsson, 1916, p. 228. 
