322 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS IIETEOROLOGY. 



with the lights of experience to guide him. The wmds and the 

 weather daily encountered by hundreds who have sailed on the same 

 voyage before liim, 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 arranged 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 tln'ough 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, may know as 

 well as the most experienced trader whether he be' m the right road 

 or no. 



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

 Close running, the route to Eio, the distance, by an au^ line, is about 



3400 miles ; but the winds and cui'rents are such as to force the 

 Eio bound vessel out of this direct liue. 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. The best navigated steam-ships do not sail closer than this, 

 A desideratum on and a better proof of the accuracy of our knoAvledge 

 ship-board. 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 fui'nished with data for determining the force of the wind 

 as well as its dhection, 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- 

 How passages have books and placed before the nautical world, the 

 been shortened. average passago from Europe or the United States to 



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



