Show changes of climate A scientist who recently investigated the causes of secular variations in temperature pera ture at the earths surface thinks that they are more probably due to hanges changes in the amount of carbonic acid in the atmosphere than to variations in the heat of the sun it if the L amount of carbonic acid that the air ahr tiow now contains contain was diminished a little nore than half balf the mean temperature til over tho the earth would it Is stated drop about eight degrees which would bo be sufficient to bring on another glacial period on the other hand an increase of carbonic add acid to between two and three times Us present amount would raise the mean temperature 15 degrees and renew the hot times of the eocene epoch |