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HYDROGRAPHIC MANUAL 



Page 548 



Mj 



Figure 119.— Interesting fathograms of the 808 Fathometer. 



I shows marine growth on almost flat bottom. K shows irregularities caused by the vertical motion of the hydrographic launch 

 due to a ground swell — the average of the peaks and valleys should be scaled where this is known to be the cause. L is an example of 

 very soft surface bottom. M is an illustration of a bar check (see 557). The scale of all fathograms in this figure is the same. They 

 are referred to more fully in the text by the reference numbers. 



