1832.] Meteorological Observations. 23 



the mountains. Mittun is half-way to Lahore, and about 500 miles 

 from the sea, and nearly 220 feet above it. The remaining 680 feet 

 we may fairly apportion to the Punjab rivers, from their greater ra- 

 pidity of course, which would give them a fall of 12 inches per mile. 



" It is an additional proof of the greater magnitude of the Indus, that 

 at its lowest it retains a velocity of two and a half miles with a medial 

 depth of 15 feet, moving throughout the year in one majestic body to 

 the ocean ; while the Ganges partakes more of the nature of a hill stream, 

 insignificant at one season, and overflowing its banks at another. 



" Before bringing these remarks on the Indus to a close, I wish to 

 add a few words regarding the effect of the tide on the two rivers. In 

 the Ganges, itruns considerably above Calcutta, whereas no impression 

 of it is perceptible in the Indus 25 miles below Tatta, or about 75 

 miles from the sea. We are either to attribute this occurrence to the 

 greater column of water resisting the approach of the sea, 

 ' Whose vanquished tide, receding fro:n the shock, 

 ' Yields to the liquid weight,' 

 or to the descent of the water of the one river being greater than that 

 of the other : the tide in the Indus certainly runs off with incredible 

 velocity, which increases as we near the sea. It would appear, that the 

 greatest mean rise of tide in the Ganges is 12 feet. I found that of the 

 Indus to be only 9 feet at full moon, but I had of course no opportuni- 

 ty of determining the mean rise of the tide as in the Ganges. The 

 tides of Western India are known to exceed those in the Bay of Bengal, 

 as the construction of docks in Bombay testifies ; and I should be dis- 

 posed to consider the rise at the mouths of the Indus and Ganges to be 

 much the same. Both rivers, from the direction of their fall into the 

 ocean, must be alike subject to an extraordinary rise of tide, from gales 

 and winds ; and with respect to the whole coast of Sinde, the south- 

 west monsoon blows so violently, even in March, as to break the water 

 at a depth of 3 and 4 fathoms, and long before its depressed shore is 

 visible to the navigator." 



Ludiana, Nov. 14, 1831. 



VIII. — Summary of Meteorological Observations made at the Surveyor 

 GeneraVs Office, in Calcutta, during the years 1829-30-31. 



The monthly tables kept by the Surveyor General, and uniformly 

 published in the Gleanings, since its commencement, are now capable 

 of furnishing three years data for the illustration of the climate of 

 Calcutta, as regards the pressure, temperature, moisture, rain, state of 



