III
Gilliatt’s Masterpiece Comes to the Rescue of That of Lethierry
Any fisherman who had been mad enough to loiter in that season in the neighbourhood of Gilliatt’s labours about this time would have been repaid for his hardihood, by a singular sight between the two Douvres.
Before his eyes would have appeared four stout beams, at equal distances, stretching from one Douvre to the other, and apparently forced into the rock, which is the firmest of all holds. On the Little Douvre, their extremities were laid and buttressed upon the projections of rock. On the Great Douvre, they had been driven in by blows of a hammer, by the powerful hand of a workman standing upright upon the beam itself. These supports were a little longer than the distance between the rocks. Hence the firmness of their hold; and hence, also, their slanting position. They touched the Great Douvre at an acute, and the Little Douvre at an obtuse angle. Their inclination was only slight; but it was unequal, which was a defect. But for this defect, they might have been supposed to be prepared to receive the planking of a deck. To these four beams were attached four sets of hoisting apparatus, each having its pendent and its tackle-fall, with the bold peculiarity of having the tackle-blocks with two sheaves at one extremity of the beam, and the simple pulleys at the opposite end. This distance, which was too great not to be perilous, was necessitated by the operations to be effected. The blocks were firm, and the pulleys strong. To this tackle-gear cables were attached, which from a distance looked like threads; while beneath this apparatus of tackle and carpentry, in the air, the massive hull of the Durande seemed suspended by threads.
She was not yet suspended, however. Under the cross beams, eight perpendicular holes had been made in the deck, four on the port, and four on the starboard side of the engine; eight other holes had been made beneath them through the keel. The cables, descending vertically from the four tackle-blocks, through the deck, passed out at the keel, and under the machinery, reentered the ship by the holes on the other side, and passing again upward through the deck, returned, and were wound round the beams. Here a sort of jigger-tackle held them in a bunch bound fast to a single cable, capable of being directed by one arm. The single cable passed over a hook, and through a deadeye, which completed the apparatus, and kept it in check. This combination compelled the four tacklings to work together, and acting as a complete restraint upon the suspending powers, became a sort of dynamical rudder in the hand of the pilot of the operation, maintaining the movements in equilibrium. The ingenious adjustment of this system of tackling had some of the simplifying qualities of the Weston pulley of these times, with a mixture of the antique polyspaston of Vitruvius. Gilliatt had discovered this, although he knew nothing of the dead Vitruvius or of the still unborn Weston. The length of the cables varied, according to the unequal declivity of the crossbeams. The ropes were dangerous, for the untarred hemp was liable to give way. Chains would have been better in this respect, but chains would not have passed well through the tackle-blocks.
The apparatus was full of defects; but as the work of one man, it was surprising. For the rest, it will be understood that many details are omitted which would render the construction perhaps intelligible to practical mechanics, but obscure to others.
The top of the funnel passed between the two beams in the middle.
Gilliatt, without suspecting it, had reconstructed, three centuries later, the mechanism of the Salbris carpenter—a mechanism rude and incorrect, and hazardous for him who would dare to use it.
Here let us remark, that the rudest defects do not prevent a mechanism from working well or ill. It may limp, but it moves. The obelisk in the square of St. Peter’s at Rome is erected in a way which offends against all the principles of statics. The carriage of the Czar Peter was so constructed that it appeared about to overturn at every step; but it travelled onward for all that. What deformities are there in the machinery of Marly! Everything that is heterodox in hydraulics. Yet it did not supply Louis XIV any the less with water.
Come what might, Gilliatt had faith. He had even anticipated success so confidently as to fix in the bulwarks of the sloop, on the day when he measured its proportions, two pairs of corresponding iron rings on each side, exactly at the same distances as the four rings on board the Durande, to which were attached the four chains of the funnel.
He had in his mind a very complete and settled plan. All the chances being against him, he had evidently determined that all the precautions at least should be on his side.
He did some things which seemed useless; a sign of attentive premeditation.
His manner of proceeding would, as we have said, have puzzled an observer, even though familiar with mechanical operations.
A witness of his labour who had seen him, for example, with enormous efforts, and at the risk of breaking his neck, driving with blows of his hammer eight or ten great nails which he had forged into the base of the two Douvres at the entrance of the defile between them, would have had some difficulty in understanding the object of these nails, and would probably have wondered what could be the use of all that trouble.
If he had then seen him measuring the portion of the fore bulwark which had remained, as we have described it, hanging on by the wreck, then attaching a strong cable to the upper edge of that portion, cutting away with strokes of his hatchet the dislocated fastenings which held it, then dragging it out of the defile, pushing the lower part by the aid of the receding tide, while he dragged the upper part; finally, by great labour, fastening with the cable this heavy mass of planks and piles wider than the entrance of the defile itself, with the nails driven into the base of the Little Douvre, the observer would perhaps have found it still more difficult to comprehend, and might have wondered why Gilliatt, if he wanted for the purpose of his operations to disencumber the space between the two rocks of this mass, had not allowed it to fall into the sea, where the tide would have carried it away.
Gilliatt had probably his reasons.
In fixing the nails in the basement of the rocks, he had taken advantage of all the cracks in the granite, enlarged them where needful, and driven in first of all wedges of wood, in which he fixed the nails. He made a rough commencement of similar preparations in the two rocks which rose at the other extremity of the narrow passage on the eastern side. He furnished with plugs of wood all the crevices, as if he desired to keep these also ready to hold nails or clamps; but this appeared to be a simple precaution, for he did not use them further. He was compelled to economise, and only to use his materials as he had need, and at the moment when the necessity for them came. This was another addition to his numerous difficulties.
As fast as one labour was accomplished another became necessary. Gilliatt passed without hesitation from task to task, and resolutely accomplished his giant strides.