696 MR. WILLIAM PARKES ON THE TIDES OF BOMBAY AND KURRACHEE. 
doubtful in some respects ; it will therefore be desirable not to place too much confi- 
dence on its records in some particulars. 
They may be depended on for, — 
1st. The forms of the mean semimonthly curves of height and time (very nearly). 
2nd. The range of tide without reference to a fixed level. 
3rd. Diurnal inequality in height or time. 
But in the following the results should be taken with some reserve : — 
1st. The actual time of any particular tide or short series of consecutive tides. 
2nd. The height of any particular tide or short series of tides above a fixed level. 
(N.B. The papers were generally renewed about once a week, and any error in placing 
a paper would be likely to be continued till it was removed.) 
3rd. The comparative duration of the times of rising and falling water. The machine 
gives the average duration of flood tide a few minutes longer than that of ebb, a result 
which is not confirmed by direct observation. 
