REPORT ON THE TIDES. 105 
In the above columns headed “ Observation” the irregulari- 
ties have been destroyed in the manner explained by me in the 
Bakerian Lecture, Phil. Trans., 1836, p.225. The quantities 
headed “London” have been reduced to transit A by means 
of certain tables also given in that paper, to which I shall again 
have occasion to allude. The London height inequality has 
been multiplied by 1°758. The quantities headed “‘Theory’’ were 
calculated by the Liverpool constants, 
log (4) = 9°56965, log (#) = 0°87130. 
The height is represented by the expression 
D + (E) {(A) cos (2 ~ — 24) + cos 24}, 
in which ¢ denotes the moon’s R.A. —sun’s R.A. wW de- 
notes the sidereal time — the moon’s R. A. 
I conceive that the best if not the only method of investi- 
gating alterations in the height of the land above the water 
in any given locality where the water is influenced by the tides, 
will be to examine carefully whether any alteration has taken 
place in the values of the constants D and (£) for that place, 
the height of high water being of course always reckoned from 
some fixed mark in the land. 
The nature of the discrepancies between the London and Li- 
verpool results is better exhibited in the following diagrams, 
where the quantities in the preceding tables have been laid down. 
The London interval curve, although agreeing in form with the 
Liverpool interval curve, differs from it throughout by several 
minutes. This difference seems to be very remarkable. The 
height curves agree closely, showing that the height inequality 
_ varies as the quantity EH, as I have supposed. Laplace says 
_ * Hiles (les marées] augmentent et diminuent avec le diamétre 
_ et le parallaxe lunaire, mais dans un plus grand rapport ;”’ but 
_ the diagram in the preceding page appears to confirm the truth 
_ of this passage only at neap tides. 
