SEA ROUTES, CALM BELTS, AND VARIABLE WINDS. 335 



chances are capable ; and farther, these results are so certain 

 that there is no longer any room for the mariner to be in doubt 

 as to the best route. When a navigator undertakes a voyage 

 now, he does it with the lights of experience to guide him. 

 The winds and the weather daily encountered by hundreds who 

 have sailed on the same voyage before him, with '* the distance 

 made good " by each one from day to day, have been tabulated 

 in a work called Sailing Directions, and they are so an^anged 

 that he may daily see how much he is ahead of time, or how far 

 he is behind time; nay, his path has been literally blazed 

 through the winds for him on the sea ; mile-posts have been set 

 up on the waves, and finger-boards planted, and time-tables 

 furnished for the trackless waste, by which the ship-master, even 

 on his first voyage to any port, ma}^ know as well as the most 

 experienced trader whether he be in the right road or no. 



623. Close running.- — From New York to the usual crossing of 

 the equator on the route to Eio, the distance, by an air line, 

 is about 3400 miles ; but the wdnds and currents are such as to 

 force the Eio bound vessel out of this direct line. Nevertheless, 

 they have been mapped down, studied, and discussed so 

 thoroughly that we may compute with remarkable precision the 

 detour that vessels attempting this route from New York, or any 

 other port, would have to make. This computation shows that, 

 instead of 3400 miles, the actual distance to be accomplished 

 through the water by vessels under canvas on this part of the 

 voyage is 4093 miles. More than a hundred sailing vessels have 

 tried it by measuring and recording the distance actually sailed 

 from day to day; their mean distance is 4099 miles, consequently 

 their actual average differs only six miles from the computed 

 average.* 



624. A desideratum on ship-hoard. — The best navigated steam- 

 ships do not sail closer than this, and a better proof of the 

 accuracy of our knowledge concerning the prevailing direction 

 of the winds at sea could not be afforded. Unfortunately, ane- 

 mometers are not used on shipboard. Had they been in common 

 use there, and had we been furnished wdth data for determining 

 the force of the wind as well as its direction, we could compute 

 the time as well as the distance required for the accomplishment 

 of any given voyage under canvas. Thus the average time 

 required to sail from New York to the equator might bo 

 * P. 146, vol. ii., Maury's Sailing Directions. 



