OBSERVED OFF THE CAPE OF GOOD HOPE. 



431 



thence diminish until they are lost. Thus a wave, marked 

 at the ship as small, niay be seen at a distance from her to 

 have a crest equal in height to one which would be marked 

 at the ship as large ; but if the eye be suffered to range 

 away in quest of the crests of passing waves, the order of 

 their size at the ship will be lost. 



Beginning with a wave larger than those ordinarily pass- 

 ing the ship at the time, I have generally found that it is 

 followed at a short distance by another equally large. 

 Between these two often appears a smaller one, which, if 

 it be watched over the bows or stern of the ship, will be 

 seen to be the spur at tbe origin or end of a larger one, 

 whose crest may be a mile off, the system being shown in 

 the accompanying rough drawing, in which the thicker 

 parts of the figures represent the greater height of the 

 waves, it being understood that in the drawing the breadth 

 (or height) of the wave is exaggerated in proportion to its 

 length, the object being merely to show how an apparently 

 small wave is situated between two larger ones. 



f>o that the line "^ ^ ^ is either a surface of little undulation, 

 bounded by parts of four large waves, or will be crossed by 

 tlie ship on the lower spur of a wave whose apex is beyond 

 or astern of her. 



Thus it appears that measurements of large waves fi'om 

 a ship do not measure so much larger undulations than 

 usual of the whole surface of the water, as points and 

 times at which the summits or crests of waves happen to 



