Tide Observations of the British Association. 1 37 



clear that the effect will be more apparent on spring tides 

 than on neaps, owing to the greater velocity of the water, and 

 so it appears to be. 



On the south coast of Cornwall the rise of ordinary spring 

 tides is about 16 to 17 feet, and of ordinary neaps a little 

 more than 7 feet. At Axmouth the rise of spring tides ap- 

 pears to be about 10 or 1 1 feet, and of neaps about 7 feet. 

 Hence we see that although the rise and fall of neaps at Ax- 

 mouth nearly corresponds with that of the south coast of 

 Cornwall, yet there is a difference of six feet in the compari- 

 son of spring tides ; this appears strongly corroborative of 

 the idea of the tide currents operating in the way I men- 

 tion. 



By a reference to the table of contemporaneous observa- 

 tions of the tides (plate 2.) accompanying the paper referred to 

 in the Transactions of the British Association, it will be seen 

 that the high- and low-water marks at Plymouth are so placed 

 that the line of mean tide shall about coincide with that of 

 the tides at Axmouth. There appears to be no authority for 

 this, as it does not appear that any levels have been extended 

 to Plymouth. For the reasons as above stated, I should con- 

 clude that the high-water mark at Axmouth would probably 

 be higher than the high water at Plymouth ; but supposing 

 it the same, then in the series of tides observed, would the 

 mean level at Plymouth be at neaps nearly one foot, and at 

 springs nearly two feet lower than at Axmouth ; and be it 

 remembered that the greatest rises at Plymouth, as stated in 

 this table, are only 14- feet, which I should consider as much 

 less than the average rise of spring tides there, seeing that on 

 the neighbouring coast of Cornwall it is nearly three feet 

 more. I should also think that the high water at Axmouth 

 is more elevated than at Falmouth: but if it be only at the 

 same level, then will the mean-tide mark be three feet higher 

 at Axmouth than at Falmouth. 



In the tide-table above referred to, it appears that the 

 mean-tide line at King-Road is about one foot above that at 

 Axmouth. In this comparison the greatest tides observed 

 at King -Road rise about 36 feet, in which series the greatest 

 difference of mean-tide level does not amount to one foot. 

 Other tides appear by the table to have been observed there, 

 some of which had a rise of 41 feet, and the range of mean 

 tide differed as much as two feet and a half. In the year 1815, 

 as before stated, I observed a series of tides at King-Road, 

 which ranged from a rise of 1 9 feet to a rise of 46 feet, dif- 

 fering in their respective elevations of mean tide as much as 

 3| feet ; the greatest tide rising from on the scale to 4-6 



