§ C23-G25. SEA ROUTES, CALM BELTS, ETC. 835 



tions, and thej are so arranged that lie 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 plant- 

 ed, and time-tables furnished for the trackless waste, by which the 

 ship-master, on his first voyage to any port, may know as well 

 as the most experienced trader whether he be in the right road 

 or no. 



623. From New York to the usual crossing of the equator on 

 Close running, the routc to Eio the distance, by an air line, is about 



8400 miles ; but the winds and currents are such as to force the 

 Eio bound vessel out of its direct line. Nevertheless, they have 

 been mapped down, studied, and discussed so thoroughly that we 

 may, using as arguments the data obtained, compute with remark- 

 able precision the detour that vessels sailing from New York or 

 any other port, and attempting this route to the equator at the 

 various seasons of the year, would have to make. This computa- 

 tion showed that, instead of 8400 miles, the actual distance to be 

 accomplished through the water by vessels under canvas on this 

 part of the voyage would be 4093 miles. More than a hundred 

 sailing vessels have tried it by measuring and recording the dis- 

 tance 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. The best-navigated steam-ships do not sail closer than this, 

 Adesideratumonship. and a bcttcr proof of the accuracy of our knowl- 

 ^^'^^^' edge concerning the prevailing direction of the 

 winds at sea could not be afforded. Unfortunately, anemometers 

 are not used on shipboard. Had they been in common use there, 

 and had we been furnished with 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 be computed within an 

 hour, for it has "been computed within an hour's sail — six miles 

 (§ 623). 



625. By the knowledge thus elaborated from old and new log- 

 books and placed before the nautical world, the average passage 



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



