ON TBE COASTS OF IREI^NO. 37 



solar and in the lanar tides, by the narrow channel which, beginning with Islay (op- 

 posite Port Rush), continues to the Mnll of Galloway (opposite Donagfaadee). Bnt I 

 profess myself totally unable to explain with greater accuracy why, in passing from 

 Muliaghmore to Ballycastle, the principal redaction of lunar tide takes place between 

 MuUaghmore and Port Rush, while the principal reduction of solar tide takes place 



between Port Rush and Ballycastle. 



* S 



The successive diminution in the values of jr from Kilbaha to Kilrush, Foynes 



Island, and Limerick, as well as the reduction from Dunmore East to New Ross, and 

 that from Port Rush to fiuncrana and Carrowkeel, are to be explained firom the other 

 consideration which I have described as applicable to rivers. In feet, in these cases, 

 from the very greatly contracted current- way at low water, the effect of variation in 

 the depression of the ocean low water is very small, and therefore the effect of semi- 

 mensti-ual inequality is sensible almost only in the high water, and its whole effect 

 on the range is therefore less than it ought to be. 



Before dismissing this table, I shall remark, that the very great diminution in the 

 range of tide in the North Channel, makes it impossible for us to believe that the 

 tide in the Irish Channel is supplied from the North Channel, however much the 

 consideration of the times in the next section may lead us, in the first instance, to 

 imagine so. 



I will now proceed with the age of the tide as shown by the heights. The method 

 employed was the following : — 



The mean heights having been found from the preceding tables, the heights for 

 every day (corrected for diurnal tide) were examined, and the time was ascertained 

 as nearly as practicable at which the height coincided with the mean heighL These 

 times were then compared with the times at which the moon*s hour-angle from the 

 sun was S*", 9^ \o\ and 21*'; namely, June, 26'* e*"; July, 4** 16^ ll'*3S 18^9^, 

 26«* 9*»; August, 3^ 0^, 9^* le**, IG** Ib^. High waters and low waters were treated 

 separately. At each place eight comparisons were obtained for high water and eight 

 for low water : excepting that in the high waters, no comparison was made at Old 

 Head with July 11^3'', and 18^ 9** (the times of mean height being very uncertain) ; 

 nor at Ballycastle, with July 1 8** 9* and 26* 9* (for the same reason), nor with June 

 26** e*" (the observations having commenced too late) ; nor at Glenarm, Donagbadee, 

 or Kingstown, with July 18** 9** and 26** 9* (the times being uncertain). The results for 

 each place being collected, and the means being taken, the following Table was 

 formed : — 



