184 Master Minds of Modern Science 



Let us give one example. A giant Atlantic liner col- 

 lided with a small cruiser in the Solent, near Southampton, 

 a few years ago. Happily there was no loss of life, but 

 the damage gave rise to difficult questions regarding 

 the responsibility for the collision. The case remained 

 at a deadlock until the Admiralty put forward a theory 

 which led to a solution. 



The authorities said that the collision might have been 

 caused by the wash of the giant liner sucking the small 

 cruiser toward her. 



It might be true, or it might not. How could the 

 theory be tested? Obviously they could not arrange 

 another collision. At least, not with real ships on the 

 Solent. But the scientists, with the aid of the Froude 

 Experimental Tank, could stage the collision — a hundred 

 times if necessary — under conditions exactly parallel with 

 those under which it had occurred. So to Teddington 

 went the President of the Court, counsel, and witnesses. 



First were built as neat models as ever delighted the 

 heart of a boy of any age up to sixty. Constructed of 

 yellow paraffin wax, they were perfect scale replicas of 

 the giant liner and the cruiser. The liner even had pas- 

 sengers, crew, and cargo represented by lumps of lead, and 

 little bags of ballast, while the cruiser was complete down 

 to her ram and rudder. Both models were fitted with 

 tiny electric motors and screws. 



Then before the lawyers and naval experts the Solent 

 collision was re-enacted. The depth of water in the tank 

 was proportionate to the depth of the sea beneath the 

 vessels when the accident occurred. 



To reproduce the speed of the ships the scientists 

 brought the ' bridge ' into operation. This is a steel 

 structure spanning the width of the tank, weighing four- 

 teen tons, and set on rails at either side, along which it 

 is electrically driven at a variable speed. Attaching the 

 two models to the undercarriage of the bridge, the models 



