OCEAN METEOROLOGY. 



191 



of the data is complete for the part of the ocean under consideration. 

 The final step is to arrange the matter in shape for the engraver and 

 printer. This is done on sheets of Form C — a blank eight inches by 

 ten — which is a fac-simile of one of the squares of the monthly charts 

 enlarged to a size suitable for writing all the data in the proper spaces. 

 The data for all the squares for one month are transcribed from Form 

 D to Form C ; these are sent to the engraver ; a proof-sheet comes 

 back in due time ; this is read and corrected ; and eventually the 

 charts themselves issue complete from the press. Until the year 1876 

 no systematic use was made of the log-books of our vessels of war. 

 Every six months they were sent from each squadron to the ISTavy De- 

 partment, where they have been accumulating since the days when 

 Maury had the supply then on hand compiled for his charts. 



Now, a large number await examination — a rich mine of valuable ma- 

 terial. A set of charts for the Pacific Ocean between the equator and 

 latitude 45° north, and from the American coast to the 180th meridian, 

 are the first fruits of labor in this mine. The complete set consists of 

 fifteen different sheets : 1. Twelve on which the information peculiar 

 to each mouth is given on a separate sheet ; 2. One that summarizes 

 all the observations of the direction and force of the wind of every 

 month and year ; 3. One that similarly gives all the observations of 

 the barometer, thermometer, and weather ; and, 4. One in colors show- 

 ing the wind systems, stormy regions, and areas of equal heat and 

 equal pressure — a graphical exhibit of what the other charts contain. 



Preceding the set are, a table giving for every month the latitude 

 and longitude in which each ship entered or lost the trade-winds ; a 

 list of the log-books whose data enter into the charts ; and a preface 

 chiefly descriptive of the method of compilation. All are printed on 

 thick paper and bound together in a folio volume convenient for use. 



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