APPENDIX B de 
value, which is used as a constant difference. With a view to allow in 
the computation for the variation in the difference, and thus to reduce 
the error, much labour has been expended; the object being to arrive at 
such relations between these three St. Lawrence stations as would enable 
the variation in the difference to be reduced to law. The investigations 
made need not be given here. For the present, it will be sufficient to 
say that no one law could be discovered under which a series of variable 
differences could be constructed, to allow for the greater part of the error 
resulting from this variation. 
The outcome of the investigation was to show that improvement in 
the present method of the use of constant differences will only be secured 
when the means are available to make an analysis of the Father Point 
record itself, and to base tide tables directly upon this. It will probably 
be found that an improvement will then be obtained by making Father 
Point, instead of Quebec, the port of reference for other points in the 
open estuary for some distance above it. Also in the other direction, an 
improvement in accuracy as far as Anticosti Island and its vicinity will 
be obtained ; as it now appears that the outstanding error in the time 
of the tide at South-west Point would thus be reduced by 20 per cent. 
The analysis of the tidal record for Father Point itself, would be in 
accord with the modern view taken by the most eminent authorities on 
tidal questions. When the means available for this Survey are so limited, 
however, that the analysis of tidal record for the principal harbours of 
_ the country has to be deferred from year to year, the hope of doing simi- 
Jar work for Father Point would seem a long way off. It is because of 
this that the exhaustive examination into the tidal relations on the Lower 
St. Lawrence, above referred to, was undertaken, in the Hope of securing 
improvement in the meantime. 
The method above referred to, will not secure any direct advantage 
for the Quebec tide tables themselves, however. The variation between 
the tides as calculated and observed at Quebec, is chiefly due to wind 
disturbance ; which is much felt in so long an estuary. Another diffi- 
culty is that technically speaking, Quebec is not well situated for a prin- 
cipal tidal station ; because it is in reality in the river, and above the 
true head of the estuary. This must be considered to be at the lower end 
of Orleans Island; as it is there that the tide has its maximum range. 
In connection with tidal work on the Lower St. Lawrence, proposed 
for the coming season, a station will be established near the lower end 
of Orleans Island; and it is hoped that simultaneous observations there 
and at Quebec, will explain some of the irregularities still unaccounted 
for ; and also enable these to be eliminated in the comparison of places 
on the Lower St. Lawrence with the tide at Quebec. 
