208 On Docks — Dnj, Wet, and Floating. 



The saving, however, in the first cost of construction would 

 amply repay any outlay of the kind ; and the objection does 

 not apply with so much force to the lifting dock, which can 

 at all times he repaired with ease and expedition, 



I will now proceed to describe, shortly, the sketches and 

 drawings wdiich I lay before the Society. 



The first is a floating dock, invented by Mr. Gilbert : — it 

 is constructed entirely of timber, appears very simple, and 

 is capable, as far as its principle is concerned, of being 

 extended to take in vessels of any size. The side chambers, 

 or camels if they may be so called, serve to support the 

 dock when the gate is opened, and the dock filled for the 

 admission of the vessel : a steam engine and pumps will be 

 necessary in order to pump the water from these chambers, 

 and from the dock itself. Mr. Gilbert's own description 

 will give all the necessary details of the construction and 

 mode of operation of this dock. 



The second set of drawings consist of five, which are 

 explanatory of all the details of Messrs. Skull and Martin's 

 floating dry dock, which is, in fact, a lifting dock, in which 

 the vessel, after being floated on to a cradle, supported partly 

 by air-tight chests or tanks, and partly by framing attached 

 to the floor on which the cradle rests, is lifted by means of 

 pinions working into racks upon this framing, — the moving 

 power being a steam engine, which turns a set of working 

 shafts connected with the pinions. 



In the drawings a large turn-table is shown, the object of 

 which is to enable the cradle, with the vessel upon it, to be 

 removed from the dock and transferred upon a railway to 

 any part of the yard connected with the dock, which might 

 thus be used for the repair of several vessels. 



The third set of drawings comprises three, which give the 

 details of another lifting dock. In this, which is of a less 

 elaborate construction than that of Messrs. Skull and 



