SOME WORLD'S WEATHER PROBLEMS 219 



seems to be of about thirty-five years in length. By a con- 

 tinuous and steady accumulation of more data, the time will 

 eventually arrive when a more accurate knowledge of the 

 lengths of these various changes will be acquired ; but at present 

 we are, so to speak, practically groping our way in the dark. 

 There is no question, however, about the importance of gaining 

 as much knowledge as possible about the lengths, phases, and 

 relative intensities of these changes of long duration. Even 

 with regard to these, compensating effects must be taking place 

 in different parts of the world, a deficiency in one region cor- 

 responding to a surplus somewhere else. The behaviour of such 

 pressure changes in a very remote region from us may there- 

 fore be of very great concern to us in trying to look into the 

 past and future of these sequences of changes. In fact, it seems 

 impossible for the investigator to take too broad a view of the 

 domain of meteorology. 



In this article an attempt has been made, and I hope with 

 some success, to acquaint the reader with some of the surges 

 which are taking place in this atmosphere of ours, and which 

 are initially responsible for the variations of weather from year 

 to year and from decade to decade. We have, however, left 

 out of consideration altogether the prime mover and originator 

 of all these varied pressure permutations. In fact, we might 

 be describing the play of Hamlet, omitting the role of the Prince 

 of Denmark ! The sun — 



Great source of day ! best image here below 

 Of thy Creator, ever pouring wide, 

 From world to world, the vital ocean round, 

 On Nature write with every beam His praise. 



Thomson's Hymn — 



as Professor Young writes in his excellent manual of Astronomy, 

 " is the nearest of the stars — a hot, self-luminous globe, enormous 

 as compared with the earth and moon, though probably only 

 of medium size compared with other stars; but, to the earth 

 and the other planets which circle around it, it is the most 

 magnificent and important of all the heavenly bodies. Its 

 attraction controls their motions, and its rays supply the energy 

 which maintains every form of activity upon their surfaces." 

 As a child of the sun, therefore, and bathed continually in his 

 rays, the earth should respond to all his varied moods if they 

 are emitted into space and represented by either an increase 



