100 Captain Newbold on the Temperature of 



of these remarks, much has been done by Prinsep and others in 

 these branches of Indian hydrography, but more remains to be ef- 

 fected before this reproach can be wiped out. The heat of springs 

 having a temperature little above the mean of the surrounding coun- 

 try has been rarely noticed, though I feel convinced many such exist 

 in India, That of springs of high temperature, more attractive to 

 the casual observer, has been more remarked. 



My own observations, and the few inferences I have ventured to draw 

 from some of them, are not offered as sufficient data for the establish- 

 ment of laws, but merely as u contributory mite to knowledge, in 

 the view of courting inquiry and observation by others more com- 

 petent and better situated for continued research than myself. The 

 thermometric observations have been snatched generally on the line 

 of march, or during hasty travel. Since my return to England, 

 through the Ikindness of Mr Roberton, they have been adjusted to 

 the indications given by the standard thermometer of the Royal 

 Society. 



The observations extend, at irregular intervals, from Alexandria 

 to Malacca, or from 31° 13' of north latitude to within 2° 14' north 

 from the equator; and between the meridians of 27° and 103° of 

 east longitude. I had continued those on the temperature of the 

 sea as far as the Bosphorus and Black Sea, but have judged them 

 superfluous in a paper limited almost to the subject of intertropical 

 temperature. 



In the columns of the registers, the latitude and longitude, the 

 approximate height above the sea, the nature of the surrounding 

 formation, the depth to the surface of the water, and depth of water, 

 the temperature of the air, the month during which each observation 

 was taken, and the approximate annual mean of the climate in which 

 the wells, &c. occur, are specified as far as practicable. In the column 

 of remarks will be found a few observations on the chemical nature 

 of the water, and on the size of the wells and springs.* Those were 

 selected which contained water all the year round, though all were 

 more or less subject to fluctuation during the wet and dry seasons. 

 The wells in Egypt differ from the ** bouries " of India in being less 

 open and exposed to atmospheric influence. Those in the valley of the 

 Nile are mere shafts sunk through the black alluvium to an imper- 

 vious marly and sandy bed, to depths varying, according to the dis- 

 tance from the river, from ten to forty feet. Their circumferences, 

 like those of the Indian '* pot wells," are from nine to twelve yards. 

 They mainly depend on the river for water, which is supplied by 

 infiltration through the soil — a circumstance to be taken into con- 

 sideration in all indications afforded of their temperature. The 



* The observations of others will be denoted in the column of remarks 

 by the names of the observers. The scale throughout is that of Fah- 

 enheit 



