ON SHIP WAVES. 493 



a ship was floated it was found to draw too much 

 water forward, in other words to be down by the 

 head. When this happened, the ship was taken 

 out of the water again, and a parallel piece, 

 I o or 20 or 30 feet long, was put into the middle : 

 a parallel middle body, curved transversely, but 

 with straight lines in the direction of its length. 

 Many a ship was also lengthened with a view to 

 add to its speed. William Froude took up the 

 question of parallel middle body, and the effect of 

 the entrance and run. The entrance is that part of 

 the ship forward, where it enters the water and 

 swells out to the full breadth of the ship ; the run 

 is the after part, extending from where the ship 

 begins to narrow to the stern. A ship may consist 

 of entrance, parallel middle body, and run. Froude 

 investigated the question, Is the parallel middle 

 body inserted in a ship an advantage or a dis- 

 advantage, in some cases or in all cases ? He 

 found it a very complex question. According to 

 the relation of the wave-length to the length of the 

 ship, it produces a good or a bad effect. A ship 

 with a considerable length of parallel middle body 



