260 Scientific Proceedings, Royal Dublin Society. 



supported from the deck of the vessel, being carried beneath a diametral 

 segment of the deck upon a base-plate (lettered J, J on Plate XIX), which is 

 rigidly attached to the deck-plate by tbe double T girder p (see transverse 

 section on drawing). The removable deck-plate is lettered K, K on the 

 drawing, and the bolt-lioles for attaching it in position are indicated by the 

 lines 0, o. It is thus easy to lift out the engines after a sounding, for the 

 purpose of cleaning and drying. 



The receptacles for receiving the water from the cylinders are in the 

 form of steel bottles. For depths up to 1000 fathoms the steel bottles upon 

 the market, and used for holding gases at high pressures, would be of ample 

 strength ; for greater depths special bottles must be provided. In the present 

 machine it is purposed to use four bottles, each of about 2| litres capacity and 

 having a length of about 60 cms. (24 inches), and each weighing when empty 

 about 9 kilograms (20 lbs.). With these bottles the cylinders communicate by 

 high-pressure steel tubing, the connections with the engine-valves being made 

 through port-holes provided in the top sides of the containing vessel. The 

 bottles are located in the lower part of the sounder, as shown in Plate XX. 



The drill-tube feeds down through the collar revolved by the engine, as 

 already stated. It is intended to give the tube a length of about \\ metre 

 (or about 5 feet). The tube will occupy the position shown in the figure when 

 the sounder is being lowered. Upon reaching the bottom the engine auto- 

 matically starts into operation by the slackening of the wire suspensions 

 attaching the sounder to the sounding-wire. These wires are four in 

 number. Two of them pass through the deck, as shown, and until the 

 bottom is reached keep the stopcocks h,h, connecting the valves with the 

 bottles, open, against the pull of two strong springs c, c. The other two 

 suspensions pass outside the vessel through guides and actuate a slip-door, 

 closing the opening in the sounder for the emergence of the drill-tube. This 

 slide-door, during descent of the sounder, is held closed by the very consider- 

 able tension on the suspensions ; on reaching the bottom it opens under the 

 pull of a strong spring, allowing the drill to descend upon the mud. Similarly, 

 when the drill is withdrawn from the mud, and the sounder is being raised 

 (in the manner to be described), the slip-door closes over its lower end, 

 protecting its contents from being washed out during the ascent of the 

 sounder to the surface. The details of these doors, being readily filled in, are 

 not shown in the figure. 



The drill-tube may be weighted by a lead and iron topping, as shown. 

 The lower or cutting edge of the drill is coarsely saw-toothed. The upper 

 end is closed by a non-return valve opening outwards. This readily permits 

 of the escape of the water as the drill enters the mud. When the drill is 



