In side-winds the machine makes leeway in addition to its forward movement, and it is the ratio of one to the other which the successful pilot must work out correctly, especially when flying above clouds or when land features are unobserved.  In this particular instance our boys were supplied with charts indicating the trend of all normal winds in each locality and their approximate force at various altitudes. Thus, by consulting his speedometer, John was able to figure out with a fair degree of certainty what allowances he should make from dead reckoning in order to strike their destination--or rather, we should say that Tom, as John's aid, did most of this figuring, for a pilot generally has his hands full in guiding his steed.