B. TERRESTRIAL PHYSICS AND METEOROLOGY. 117 



vides the heavens into ten equal portions, zero representing 

 an entire absence of clouds, and ten a completely cloudy sky. 

 By a system of tints he represents the various classes of 

 clouds, a white tint representing cirrus, a gray tint the cumu- 

 lus, and a neutral tint the nimbus. It follows from this com- 

 bination that, by a simple inspection of the tables, one can 

 see how the cloudy periods succeed each other. By compar- 

 ing these various changes in the appearance of the heavens 

 with the oscillations of the barometer, thermometer, anemom- 

 eter, etc., one easily comj^rehends the relations and connec- 

 tions which exist between these various elements. The 

 volume of observations tliat M. Balard has represented in 

 this descriptive manner embraces the past twelve years, al- 

 though he states that it is now thirty years since he resolved 

 to accumulate with order and method all the data that could 

 serve as the base of a very extended w^ork Avhich he has un- 

 dertaken on the movements of the atmosphere. 6 i?, 1873, 

 585. 



THE METEOROLOGY OF THE DOLDRUMS. 



The Meteorological Office at London has just published a 

 long-expected contribution to the meteorology of the Atlantic 

 Ocean. For nearly twenty 3'ears the captains of a number 

 of the principal lines that navigate these waters have kept 

 for the office quite accurate and minute notices of the w^eather, 

 temperature of the sea, currents, etc. These have been plot- 

 ted by Captain Toynbee upon large charts ; and the recent 

 publication to which we allude consists in the reproduction, 

 on a sufficiently large scale, of these charts (one for each 

 month of the year), for that section of the Atlantic Ocean 

 that is bounded by the equator and 10 north latitude, and 

 by the meridians 20 and 30 west. This square has been 

 selected as one through Avhich most vessels pass in crossing 

 the equator, and one which is of great importance in a mete- 

 orological point of view.. 



These charts will be followed by others, giving a complete 

 study of the region of equatorial calms, or "the doldrums." 

 This region consists of a narrow belt, from one to three 

 hundred miles wide, crossing the Atlantic Ocean parallel to 

 the equator, which slowly moves northward in our summer, 

 and southward in our winter, following the changing decli- 



