INVENTIOXS AT PANAMA. 



153 



trated by cuts, describes this conp-ivunce, and also another of the 

 improvements of Couvreux, These applied, by-the-way, to the buck- 

 ets and chains of dredges as well as to those of excavators. 



Professor J. E. Nourse, U. S. Navy, in his report on the Suez 

 Canal, published in 1884, says (p. 69) with reference to the French 

 excavator : 



In 1865 Couvreux invented a di-y dredger which he called the excavateur 

 c7iar(jeur. This was a dredger inonnted on a car which ran on a tramway par- 

 allel with the canal. Its chains and iron buckets descended to scoop up the 

 sand, emptving it into cars, which were themselves drawn up to the summit of 

 the embankment along a succession of tramways. 



In the above extract the method is designated by which the earth 

 scooped up by the excavator is got rid of — that is, by means of dirt- 

 cars on common traclis. The methods by which the earth brought up 

 by dredges was disposed of were three in number : By the first the 

 sand was emptied into a hopper and thence conveyed through a duct, 

 two hundred and twenty feet long, to and beyond the banks. Steam- 

 pumps injected water into the hopper, thus facilitating the discharge. 

 Such a dredge was called a dragve d long couloir. At times the 

 banks were too high to admit of this process, and recourse was had to 

 the second method, a mechanism called the elevateur. It consisted of 

 an elevated railroad, supported by iron posts, partly upon the bank 

 and partly ixpon a barge between the bank and dredge. Sometimes 

 the dirt-cars carried the earth to a height of fifty-six feet. The cars 

 were attached to an endless chain, and passing upward along the road 

 were emptied, and returned underneath the track. Cuts of these parts 

 of the machinery may be found in Professor Nourse's report already 

 referred to. The third method was the common one of barges or 

 lighters. These were furnished with engines, and carried their con- 

 tents either to lakes along the line of the canal, or near either termi- 

 nus, to the sea, and were emptied by means of undei*- or side-doors. 



While, in executing an undertaking like that at Suez, the work con- 

 sists chiefly in digging, certain parts require to be built up in the 

 proper sense of the term. It was necessary to establish upon the 

 Mediterranean an artificial harbor, and two jetties were constructed. 

 Here was founded the city of Port Said. In the construction of these 

 piers we have an example of the way in which the adversaries of the 

 undertaking asserted, without any sufficient basis, the impracticabil- 

 ity of the work. The " Edinburgh Review," referring to the con- 

 struction of the jetties, said : "Any constructions attempted so as to 

 form an entrance for the canal will be swallowed up. Every block, 

 every stone, will be swallowed up, and we shall not see a single one 

 above water." Mr. Fitzgerald quotes this passage. Referring in par- 

 ticular to the w'estern pier, supposed to be specially difficult of con- 

 struction, because it was to arrest large bodies of sand moving at this 



