I wish to preface this statement of my views with an acknowledgment of my indebtedness to the works of Major Gold, Mr W. H. Dines, Sir Napier Shaw, Captain Cave, and Mr Lempfert, and more especially to the suggestions of Captain G. W. Jones, R.A.F. Captain Jones was the first person to draw my attention to the fact that changes in the upper wind frequently precede changes in the lower wind. In addition, he has often expressed to me his conviction that the entire theory of the winds requires to be rewritten; that convection and surface friction are of much less importance than is generally supposed, and that we have no reason to regard the variations of the upper winds as less, either in magnitude or abruptness, than those of the lower winds.