The Tides. 225 



there is a tide on the west shore of the Netherlands in the same 

 latitude. The course of the Severn, before noticed, is eastward 

 from the sea, so also the direction of the Bay of Fandy, with 70 

 feet tide. These facts are suffioient to show that the tide does not 

 follow the moon in her apparent course from east to west, while 

 the earth is revolving on its axis from west to east. 



For the purpose of attracting attention to coincidences, a few 

 ■of the principal mountain chains are given on the chart of which 

 the tides and the conformation of the coasts are, however, the 

 principal features. It will be observed that after forming in the 

 deepest part of the oceans, the first point of impact of the tides 

 is against the foot of a chain of mountains. The indentations of 

 the coasts are not wholly the effect of tidal abrasion, as is indi- 

 cate \ by the parallel position of the mountains, but indicate that 

 the tide producing force now operative was active in contributing 

 towards the formation of continents in a fluid much denser than 

 that which it now propels. 



By observing the beginning and progress of a storm at sea, we 

 may form some idea of how nature has grown into equilibrium, 

 "When the storm begins the waves are varied in form and size and 

 their motions are tumultuous, but when at length sufficient matter 

 is s^t in motion to satisfy the conditions between the force acting 

 and the surface under action, then the waves become perfect in 

 form and their regularity will bear comparison with the tides. 



The tide producing force necessarily acts upon all bodies of 

 water, either great or small, but its effect is very different in lakes 

 and inland seas from what it is in the oceans. In the former there 

 is a constant and ineffectual effort to produce regularity, in the 

 latter the o-cillation is established. 



The mass and extent of surface must be proportioned to the 

 force. In inland lakes and seas there are continued fluctuations, 

 but small, and the intervals are short, the duration being from a 

 few minutes to several hours. 



These oscillations are the result of the tide producing force and 

 the irregulaiity is the effect of interference and reaction, the sur- 

 face, mass and force not being in correct proportion. 



The lake and also ocean tides may be illustrated by a simple 

 15 



