REPORT ON TIDE CALCULATIONS. 



17 



These grants are donations only : but it has been intimated to 

 me that they may be repeated. 



A few days ago I laid down the Bassadore intervals, which 

 you have copied into your paper, for the sake of looking at the 

 enormous diurnal inequality which appears in them. I have not 

 the diagram at hand, but I remember being struck with the great 

 disparity between the acceleration of the time of H. W. after a 

 given transit — say the superior, — when the moon was on 07ie 

 side of the equator, and the retardation when she was on the 

 other ; thus : — 



These observations having been made in the month of No- 

 vember, a part of this disparity may perhaps be due to the sun, 

 which has then considerable south declination ; but if the same 

 thmg be observed in the summer months, shall we not have 

 here another case similar to that of Bristol, where the H. W. 

 next after a south transit is, about three times out of four all 

 through the year, earlier than that after a north transit, as I 

 have already remarked ? 



I am. Dear Sir, &c. 



T. G. BUNT. 



In the Philosophical Transactions for 1839, Parti, page 151, 

 will be found a further discussion of observations of high and 

 low water at Plymouth, showing that the height of mean water 

 at that place is nearly permanent; also a comparison of the 

 high and low water at Leith, showing that at that place the 

 height of mean water is still more nearly permanent, the varia- 

 tion being only a very few inches. 



The accompanying curves (Plates III. and IV.) exhibit the 

 results of the equal altitude observations referred to in Mr. 

 Bunt's letter. The times of H. W. here employed are not the 

 moments when the water is observed to be highest, but the mo- 



