1() Alec IVilftou on 



or so by wooden distance-pieces. Shortly before the launch is 

 due, melted tallow and soft so;t,i) aie run into the space between 

 the ways, the distance-pieces are removed and the wedges driven 

 home. 



As soon as the ways have been greased, meii begin to remove 

 the forest of supporting shores, thus letting the shii) gradually down 

 upon the launch way with her whole Aveight. Something is now 

 necessary to hold the vessel from sliding down nntil the proper 

 moment, something to lock the sliding way to the standing way 

 so that no movement can begin until the locking device is 

 released. It consists essentially of a pivotted lever, the lower 

 end of which bears upon the head of the ram of an hydraulic 

 cylinder, while the upper end or projection of the heavy lever 

 stands above the level of the greased standing way and engages 

 in a steel socket fitted in the under side of the sliding way. 

 About five minutes before the time fixed for the launch, the last 

 supporting timbers are cut away and the hull is held entirely by 

 this trigger. As soon as the signal is given, the man in charge 

 opens a valve not much more imposing than a kitchen tap, releasing 

 the ram. The ship is then free to slide down, forcing the 

 trigger round upon its axis as the ram is driven back, and the 

 upper projection of the lever sinks down into a groove in the body 

 of the standing way. So the huge hull is loosed for a first 

 voyage, in which it is driven solely by the force of gravity. 

 On the first occasion on which this trigger was used, a moderate 

 sized vessel was chosen. It was estimated that, if the appliance 

 was to be powerful enough to hold the " Oceanic," it ought to be 

 capable of doing much more with a lighter boat. When all was 

 ready for launching, the pumps were turned on, and the pressure 

 in the cylinder was increased rapidly for a few seconds before 

 the order for release was given. In the interval the anticipated 

 effect took place ; the boat wiis shifted bodily uphill about 

 an inch. 



It will be readily understood that at bow and stern, more 

 especially under the bow, the tapering wedge-shape of the hull 



