260 



TIDES IN THE 



The map No, 1, is made for the year 1 806-7, and I have upon the same 

 map, traced the tides for the year 1825-26, The phases of the moon in 

 the latter year falling nearly on the same days, and thus enabling me to 

 give two years together, and to shew the variation between them, at a dis- 

 tance of nineteen years. 



Map No. 2, is similar to the first in principle, but has been chosen 

 to shew three distinct inundations, that took place in the yenr 1823. 

 The first of which was occasioned by the sea, and the second and third by 

 the Ganges and Damoda rivers. The first was a very rare occurrence, 

 happening not oftener, perhaps, than once in a century ; the last nearly 

 as rare, but the second occurs every sixth or seventh year. 



Map No, 3, consisting of twelve parts, one for each month, is a daily 

 and nightly record of the river, for the said remarkable year 1822-23. 



Map No. 4, gives a comparison of the range of high, and low water 

 for successive years, from 1806 to 1827. 



These tide-tables, formed from a register kept for twenty-two years, 

 establish, beyond dispute, the lowest fall and the highest rise of the 

 Hoogly, and thus form natural points for the construction of a River Gage, 

 for the purpose of obtaining, at all times, the levels that may be required 

 for the formation of canals, docks, wharfs, and drains. They also shew 

 the height of the river at all times of the year, a matter of considerable 

 importance in the formation of public works, especially as the variation 

 is so great, at its different periods. 



I shall now advert to the local causes which affect the tides in the 

 Hoogly, The maps commence with March, in the beginning of which 



the 



