[DAWson] PROGRESS OF THE TIDE IN DEEP INLETS 125 
58 minutes, as the above values are averages for a quarter of the 
month, and not the maximum and minimum at springs and neaps. 
In the estuary of the Fraser river in British Columbia, where the 
variation in the range of the tide is more pronounced, the endeavour 
to reduce the time-interval to a function of the height of the tide was 
successful. Throughout the Strait of Georgia the high waters and 
half tides are not far from the same level; but once in the day the tide 
falls very low, at the lower low water. The whole range is 15 feet at its 
greatest. 
The following tidal differences give the time of the tide at New 
Westminster, 22 miles up the Fraser river, with relation to Sand Heads 
at its mouth. These differences are derived from simultaneous observa- 
tions, day and night, during two complete years. 
For higher high water, add 1h.00m. For either of the half tides, 
add 1 h. 00m. also; but during the freshet months, which are usually 
May, June and July, add 1 h. 14m. 
The lower low water arrives later as the height becomes less, as it 
is then more retarded. The difference of time to be added, according 
to the height in the tide tables for Sand Heads, is indicated below in 
hours and minutes :— 
Height in Sand Heads 
Mideables 4.5 .- Hate Gb trig] =) De IMC MIN OMAN: 
Add, for lower Low 
Water eee nr Das 2:28 2:47 3:04 3:16 3:25 Sroo 
It is here evident that the time-interval is an inverse function of 
the height to which low water falls; but not a linear function, as shown 
when plotted out graphically, as a curve. 
Deep Estuaries and Inlets.—These afford a complete contrast to 
ordinary estuaries; for when the depth is great, there is no progress 
of the tidal undulation in the ordinary sense. Even on the Lower St. 
Lawrence, towards the mouth of the estuary, this is exemplified. From 
Cape Chat to Father Point, where the depth is 124 to 189 fathoms in 
the offing, the time-interval on a distance of 90 miles is only 8m. at 
high water and 10m. at low water. Also, in the Strait of Georgia the 
tide is very nearly simultaneous from the tidal station at Sand Heads 
to Comox, a distance of 88 miles. From Sand Heads to Lund at the 
northern end of the strait, a distance of 108 miles, the time-interval 
is only 14m. at high water and 18m. at low water. The depth varies 
from 90 to 180 fathoms throughout, and in places exceeds 200 fathoms. 
The long inlets or Fjords on the coast of British Columbia afford 
a still more noticeable example. These are often 50 or 60 miles long 
