+-----------------------------------------------------------+ | | | TABLE 2 | | | | TYPES OF CLIMATIC SEQUENCE | | | | 1. Cosmic uniformity. 7. Brueckner periods. | | 2. Secular progression. 8. Sunspot cycles. | | 3. Geologic oscillations. 9. Seasonal alternations. | | 4. Glacial fluctuations. 10. Pleionian migrations. | | 5. Orbital precessions. 11. Cyclonic vacillations. | | 6. Historical pulsations. 12. Daily vibrations. | | | +-----------------------------------------------------------+ In assigning names to the various types an attempt has been made to indicate something of the nature of the sequence so far as duration, periodicity, and general tendencies are concerned. Not even the rich English language of the twentieth century, however, furnishes words with enough shades of meaning to express all that is desired. Moreover, except in degree, there is no sharp distinction between some of the related types, such as glacial fluctuations and historic pulsations. Yet, taken as a whole, the table brings out the great contrast between two absolutely diverse extremes. At the one end lies well-nigh eternal uniformity, or an extremely slow progress in one direction throughout countless ages; at the other, rapid and regular vibrations from day to day, or else irregular and seemingly unsystematic vacillations due to cyclonic storms, both of which types are repeated millions of times during even a single glacial fluctuation.