192 Report of the Meteorological Committee. [Jan. 20, 



O. 20. Charts of Meteorological Data for Square 3, lat. 0°-10° N., 

 long. 20°-30° W., and Beniarks to accompany the Monthly- 

 Charts, 319 pp. 



The charts show the means for all the elements for 2° squares, 

 and consequently the best routes across the equator in each 

 month ; and the remarks contain extracts relating to currents, 

 clouds, sea temperature, specific gravity, wind, weather, natural 

 history, &c. 



In an Appendix is given a Discussion of Four-hourly means 

 of the Barometer, and Air and Sea Temperature for each 

 Month and for the Tear in the Northern and Southern Halves 

 of the Square, from which have been calculated the diurnal- 

 range corrections for the district. 



This is the most elaborate paper ever published for any 

 portion of the* ocean ; and the large relative proportion of labour 

 bestowed on the district is justified by the considerations that 

 the amount of material existing for it is quite exceptional, and 

 that it lies on the highroad between the North and South 

 Atlantic, and is the meeting-place of the two trade-winds. 



The meteorologist thus finds the materials for a study of the 

 conditions of wind, ocean-currents, weather, &c. in a region 

 where two great currents of air are always meeting, with in- 

 formation as to the diurnal march of pressure and temperature 

 in the region of the equator and at sea ; while the sailor finds, 

 in the monthly charts, diagrams of what he may expect to 

 encounter on his passage through the Square at any season ; and 

 in the text containing the explanations he finds a discussion of 

 the entire mass of information, and, as a final conclusion, advice 

 as to the best route for crossing the Line in each month. 



The public will, however, be in a much better position to 

 judge of the work of the Office when the Charts, &c. now 

 in the press, for the nine squares (lat. 10° S.-20 N., long. 

 10°-40° W.), of which Square 3 forms the centre, are published. 

 In these charts, as dealing with a larger area and stretching 

 from shore to shore of the Atlantic, are given not only charts 

 of the same character as those above described (though for 

 larger areas, owing to comparative deficiency of material), but 

 also diagrams showing the direction of wind in connexion with 

 atmospherical pressure and temperature, and of ocean-currents 

 with sea-temperature. 



There is also given a tabular statement contrasting the 

 specific gravity of the sea in the easterly [going] or " Guinea " 

 current and in the westerly currents due to each trade-wind. 



In the Eemarks copious quotations are made from the Logs 

 in relation to the various phenomena which come under the 



