328 



Machine for Dredging the Paumhmi Passage. 



described dimensions would support the crew of a thousand ton ship. 

 Each raft when packed woukl occupy a space 21 feet long by 2 high and 

 2 broad, which being so inconsiderable might be taken from the tparter 

 deck, and immediately under the bulvv^arks, where the whole of the 

 equipment might lie entirely out of the way, and in nowise interfering 

 with the working of the ship. Three ropes having their ends fastened in 

 th{? loops of the lowest plank may be carried over the raft and fastened 

 to the opposite side, to add to the security to those on board in giving 

 them something to cling to, they would also serve to tie up the planks 

 with, when they are shut up. There is no chance of the hinges giving 

 under the pressia-e of the superincumbent v/eight as those parts of the 

 planks to vvhich thej^ are fastened rest upon the sleepers. I add a 

 plan of the platform under different views, and half a sheet of foolscap 

 doubled up in reverse folds in illustration of the principle of the con- 

 trivance, which may be also applied to military purposes. 



IV. — Plan of a Machine for dredging the Paumban Passage.— By 

 Lieut. Congrcve. 



To the Editor of the Madras Journal of Literature and Science. 



Sir, — If you view the accompanying plan of a machine for dfedging 

 the passage through the horse shoe sand bank at Paumban, not entirely 

 undeserving of a place in the Madras Journal of Literature and Science, 

 I vvould feel obliged by your finding room for it therein. 



The machine, to the best of my judgment, possesses some claim to 

 originality, for although the common dredging apparatus employed by 

 civil engineers at home, and worked by steam, consists in a succession 

 of buckets attached to a revolving chain, the position of these vessels 

 has, I suspect, never hitherto been so arranged, that, their contents, on 

 being discharged, shall aid the movement of the engine. 



It is incumbent on me to mention, that the plan was originally sub- 

 mitted to the Board of Revenue, but objected to by that body, owing to a 

 still simpler contrivance having been already adopted for clearing out 

 the canal through the brink. 



The subjoined extracts from my letter, I apprehend, will be sufficient 

 ^o convey a just conception of the merits of my contrivance, though I am 

 concerned that the little leisure I at present enjoy precludes me from 

 enterin:;- more fuUy into ity details. 



