88 



There is no roason to suppose that pny study of the surfoce 

 temperature of the sea, of th- evaporation, or of the variations in 

 the ocean currents, no metter how detailed, could ..ver assist the 

 gen -ral daily forecast, wheth-^r for sea or for land, because what- 

 ever chang-es take plvsce within the- s;a (=ithrr with the alternations 

 of the seasons or following cxtrs-torrestrial caus-^s) are events 

 inordinately slow as contrasted with the sudden fluctuations in the 

 atmosphere. Tho goal th^tt som? students believe attainable here is 

 quite a different one, namely, the prediction of the seasonal weath'=r 

 character over the adjacent lands to leeward. 



Ordinary weather forecasting, such as is now carried on by most 

 of the civilized governments, has become so much a matter of course, 

 is usually so well verified and is so universally used as a guide, 

 that there is a constant demand for longer range prediction of just 

 the sort that the proponents of forecasts based on sea temperatures 

 hope to see realized; namely, to tell us weeks or months in advance 

 whether high or low temperatures, much or little rainfall will pre- 

 vail. Even in regions where the weather fluctuates widely from day 

 to day it would, in many cases, be of great economic value to know 

 in advance the direction of abnormality to be anticipated in these 

 respects, even if its amount could not be foreseen. Thus a departure 

 of a d.cgree or two, plus or minus, from the normal temperature in 

 winter may govern whether most of the precipitation of a northern 

 region comes as rain, or as snow, correspondingly affecting the ease 

 of transportation, etc. In short, advance information of this sort 

 would be so helpful a guide to many industries (we need only instance 

 the clothing trades, power and transportation companies, and certain 

 branches of agriculture) that attempts in that direction are constant- 

 ly being made. And proof that industry as a whole would actually 

 welcome assistance of this sort is found in the fact that many con- 

 cerns are willing to pay high for such forecasts, even while realiz- 

 ing that their dependability is doubtful, to say the least. 



Forecasts of this sort are given out from one source or another 

 in all parts of the world, but most of them soon prove worthless. 

 In fact few of them have had any physical basis, while the sponsors 

 of those few would be the first to declare that the data for their 

 calculations have been far from adequate. Even such of the long 

 range forecasts as are based on tangible factors hav5, as a rule, 

 been purely empiric: deduced, for example from Astronomical cycles, 

 (planetary or solar), from correlations, or on the assumption that 

 a periodicity recorded in the past will recur in the future. In 

 most cases the publication of long-range forecasts has been abandoned 

 before long, discredited by too frequent a failure, on the part of 

 the weather, to substantiate the predictions. (it is necessary to 

 except India from this statement, government forecasts of the summ-^r 

 monsoon rainfall, based on oscillations in atmospheric pressure at 

 stations bordering the Indian ocean, having been reasonably success- 

 ful in the long run, and well verified in occasional years, though 

 poorly in other years. ) 



In short, no one has yet worked out a dependable sequence from 

 antecedent events, whether in sky, in sea, or on land, from which the 

 weather to come can yet be forecasted far in advance for any consider- 

 able part of the earth's surface, reliably enough to serve as a 

 trustworthy guide to man's activities, year after year. 



