248 



METEOROLOGY. 



tad 



results merely been deduced from tlie two daily extremes of heat and cold^ or tlie dew-points 

 calculated from those observations only. 



In addition to all these observations, the 21st day of eacb montli, as the regular meteorological 

 term-day, was carefully noted by the record of observations for each hour of the twenty-four. 



The remainder of the meteorological data serves in a great measure merely for the calculation 

 of the elevation of points on the line of survey or travel. These results will be found 

 in the different profiles of the country over which the line passed. 



embodied 



same 



me 



must be more 



adopted. 



This elevation varies slightly from that of El Paso. 



In the computation for elevation I have used the French formula of Delcros, and have 

 employed some other corrections consequent upon the value of horary variation, founded on 

 the observations for that quantity taten at San Elceario. In most instances, ho'wever, the 

 points of observation were too remote from the fixed observatory for the horary correction to be 

 of any great value. In these the usual corrections for temperature, &c., only were used. 



The effect of the direction and force of the wind on the mercury of the barometer has been 

 referred to above, and I mention it here only to state that my observations on this subject were 

 sufficient to assure me of the great necessity of noticing these values in connexion with the 

 barometer more particularly when observations are being made for altitude. The exact value 

 of the quantity I have not ascertained, but that it exists I am confident ; and I trust that future 

 and more prolonged observations will fix the value in a manner sufficiently accurate for its use 

 as a correction in barometrical computations. 



All of which is respectfully submitted by your obedient servant, 



MARINE T. W. CHANDLER, 



{ in charge of Meteorological Depa 



William 



Commissioner United States and Mexican Boundary Survey. 



XoTE. — Of tlio immense miiss of materials coHected, showing the meteorological character of the country adjacent to the 



boundary line, I have deemed it proper to produce here only a short abstract from the tables. Those who may desire 



further informatiou can obUiin it by reference to the records filed in the Department of the Interior. 



W. H. E. 



