OCEAN METEOROLOGY. 195 



2. Supposing the data obtainable, the organization essential to deal- 

 ing with it in such detail would be immense : a lifetime would hardly 

 suffice to reach a practical result. 



3. Its publication would require five times as many volumes as the 

 present system — a series already bulky enough to deter any one from 

 increasing it. 



4. Throughout by far the greater part of the ocean, the several 

 quantities do not vary rapidly enough to warrant compiling them for 

 such small areas. 



The prevailing direction and force of the wind are substantially the 

 same in many adjoining 1° squares ; and so also are the pressure and 

 temperature of the air, the weather, etc. : therefore, to classify them 

 for 1° squares Avould only be multiplying what, for the most part, was 

 equally applicable to the whole extent of a .5° square. 



Besides, the object sought by the 1° system, the determination of 

 the well-defined limits of the different phenomena, is more accurately 

 attained by a method pursued in connection with the 5° system : on a 

 Mercator's projection of very large scale, all the observations relating 

 to one subject of inquiry are plotted in the position where they were 

 observed. For example, the winds : at each noon position of the ship, 

 an arrow is drawn to indicate its direction, and a small figure placed 

 beside it to denote the force ; a circle represents calms, and several 

 short lines radiating from a point, light variable airs. 



This continued until the whole sheet is studded with symbols, it is 

 evident that we can determine, not to the closeness of one degree 

 only, but to within a few miles, the precise area covered by the trades, 

 or calms, or monsoons, or irregular breezes. The observations of the 

 temperature of the air, of the sea-water, and of the barometer, are all 

 similarly plotted, each on a sheet by itself. In every instance the sym- 

 bols are in different colors, to distinguish the data peculiar to each 

 month. 



In order to determine with the greatest possible precision the limits 

 of the Gulf Stream, as well as the veins of varied temperature that per- 

 meate it, a separate sheet for each month on an unusually large scale is 

 provided for the observations relating to it. 



It might seem that, instead of publishing such elaborate charts as 

 the series described, a single sheet containing merely the conclusions 

 arrived at would suffice — a chart showing those courses fi-om port to 

 port on which the most favorable winds and weather would be found. 

 As well lay railway-tracks over the ocean and expect ships to glide 

 upon them ! In matters pertaining to their profession, none are more 

 tenacious of their opinions than sailors — and justly so : they form 

 them after hard experience. To dislodge those opinions it must be 

 proved wherein they are faulty and others correct ; and this can not be 

 done by mere results. To lay down a rigid rule for a man to follow 

 is to deprive him of the exercise of discretion and judgment — quali- 



