397 
of Edinburgh, Session 1881-82. 
imagine the average lunar tide for the whole earth to consist of a 
displacement of the water, presenting protuberances, not exactly 
towards moon and anti-moon, but in a line inclined at an angle to 
the line joining moon and anti-moon, in the direction indicated by 
S 
I 
l 
big. 1 . Fig. 2. 
the drawing (fig. 1), in which M, A represent the directions of 
moon and anti -moon, and H, H' the crowns of the ideal spheroid, 
representing the average water-level for the whole earth. The 
angle HCM is made 87° 30', which would he actually the case if 
lunar tide alone as if there were no solar tide, 6 o’clock will mean 6 lunar 
hours before or after a lunar transit. 
