98 TEE CRUISE OF THE " CACHALOT." 



upon, and every landfall made becomes a new departure 

 from whence to base one's calculations, which, rough as 

 they are, rarely err more than a few days. 



Say, for instance, you are bound for Calcutta. The 

 first of the north-east trades will give a fair idea of your 

 latitude being about the edge of the tropics somewhere, 

 or say from 20° to 25° N., whether you have sighted 

 any of the islands or not. Then away you go before 

 the wind down towards the Equator, the approach to 

 which is notified by the loss of the trade and the dirty, 

 changeable weather of the " doldrums." That weary bit 

 of work over, along come the south-east trades, making 

 you brace " sharp up," and sometimes driving you un- 

 comfortably near the Brazilian coast. Presently more 

 " doldrums," with a good deal more wind in them than 

 in the " wariables " of the line latitude. The brave 

 " westerly " will come along by-and-by and release you, 

 and, with a staggering press of sail carried to the reliable 

 gale, away you go for the long stretch of a hundred 

 degrees or so eastward. You will very likely sight 

 Tristan d'Acuuha or Gough Island ; but, if not, the course 

 will keep you fairly well informed of your longitude, 

 since most ships make more or less of a great circle 

 track. Instead of steering due East for the whole distance, 

 they make for some southerly latitude by running along 

 the arc of a great circle, then run due east for a thousand 

 miles or so before gradually working north again. These 

 alterations in the courses tell the foremast hand nearly 

 all he wants to know, slight as they are. You will most 

 probably sight Amsterdam Island or St. Paul's in about 

 77° E. ; but whether you do or not, the big change made 

 in the course, to say nothing of the difference in the 

 weather and temperature, say loudly that your long 



