The importance of the science of aerology is increasing steadily with the advance of aviation, of agriculture, and so on. The interest is widespread, if one can judge by (until recently) the universality of weather reports. (Perhaps in the curtailment today lies another reason for publication of this book at this time). There is a small part of the book given to a record of personal experience in high altitude flying, but primarily the book is a study of the tremendous advance made in instruments, in theory of meteorology, in application of advance data. A chapter on amateurs, on weather in the air and on the water -- and some venture in prophecy.