From Charmbers' journal.(Concluded from page 273.) When the Great Eastern left Portland for Brest, after tak ing in her stipply of coal, she had on board about four hun dred and fifty persons, including the members of the electri cal and engineering staffs, the cable hands, and the crew ; and one would think, looking at the list of stores that the whole of London had been ransacked for the sustentation and inner j edification of this miniature army during the voyage to New foundland and baJik. Leaving out a thousand items of but little consequence, we need only refer to the 100,000 pounds of meat and poultry, 30 tuns of vegetables, 35 tuns of bread and flour, 15,000 eggs, and over 3,000 dozen of liquors of vari ous kinds, to give our readers some idea of the provision necessary to be made for a six weeks' trip. We have made a rough cJculation of the cargo of the ship, including her engines and boilers, when she left Portland, and believe the following to be a very near approximation— it is certainly not oii r the mark : Cable, 5,530 tuns ; cable-tanks and water, 400 tuns ; timber sliorings for tanks, 500 tuns ; paying-out and pieking-iip machinery, 120 tuns ; ship's stores, 250 tuns ; (joals, 6,400 tuns ; engines and boilers, 3,500 tuns ; total, 16,690 tuns. Her draft at starting was about 84 feet aft, and 38 feet forward. This, of course, decreased as the cable was paid oat, luitil, at the end of the voyage, it was oiily about 35 feet affc, and 33 forward. H-efore proceeding with a narrative of the laying of the cable, we wish to describe the arrangements made for the elec-1 trical testing of it during submersion. These were, with one | or two slight exceptions, identically the same as in 1866. | ? hoir most interesting feature is the keeping up of a constant te.t on ship and siioro for insulation, by a plan devised by Mr Vf iliougbby Smiih in 1865, at the same time allowing of tests for the continuity of the conductor, and free communication between ship and shore to be kept up without in any way in-terlbring with the insulation test. By this means, should a " fault" pass overboard inta the sea, it is detected at once, and the paying-out may be stopped before any considerable length i of the cable has bein allowed to run out. The advantage of this system over the old is apparent from the fact, that for merly it was possible for three or four miles of cable to run out between the occurrence of tlie fault and its detection ; whereas now, except under very peculiar circumstances, with in two or three minutes after a " fault" passes overboard, it can bo detected, and the signal given to stop the ship. In conclusion, nothing that could in the least possible way facilitate the execution of the great work was left undone. All the arrangements were of the most complete character, : and were placed in charge of men who are unrivaled for their practical knowledge of submarine telegraphy. The expedition started from Brest on Monday, the 31st of June, and tliu American end of the cable was safely landed! at DuSbary, near Boston, on Friday, the 33d July. The five ! weeks which elapsed betwei ? those two dates were enlivened with incidents of llio nii)st interesting nature, and it is to tliese wo shall now refer. For the first three days all went well. The weather was very fine ; the paying out of the cable proceeded without a hitch, and all were beginning to indulge hopes that, as in 1866, the voyage would be made without the occurrence of those unfortunate " faults" which cause such delay and trou ble. But our hopes were soon upset, for on the fourth day, the 34th June, shortly after daybreak, we were struck with consternation by the intelligence that there existed an elec trical fault in the cable. The intelligence was conveyed all over the ship by means of a powerful gong, which was planted outside the electrical r-ooiii,roatly to be hammered upon as soon as anything of a suspicious nature was indicated on the testing iiiBtniuietits, In obedience to the gong, the ship was speedily stopped, and the engines reversed. The tests i showed the fault to exist very near the ship ; so, without anf more ado, the pictiiiH'-np engines were set to work, and haul ing back commenced. At every three hundred or four hun dred yards of cable hauled back, a fresh test was made, until, in about a eoaple of hours, it was found that the faulty place had come on board. Other two hours were sufficient to make a fresh splice between the cable paid out and that re maining on the ship, and then operations were resumed as if nothing had happened. Fortunately, the weather was very fine and the sea calm, and the hauling back was in conse quence attended with but little danger. The occurrence of the fault was perhaps advantageous, inasmuch as it served more fully to impress the staff with the importance of having everything in c mplete readiness for an accident. The fault was afterwards found to consist of a minute hole penetrating the coatings of gutta-percha ; whether caused ac cidentally or purposrtly it is impossible to say. It may be asked why it could not have been discovered before it left the tank. The answer probably is, that it was of too minute a nature to indicate its existence on the testing instruments, until, by passing through the paying-out machines, and then undergoing the pressure of the sea, it became more fully de veloped. To give our readers some idea as to how a fault is detected, we may (for this purpose only) compare the cable to a long pipe, sealed up at one end into which water is being forced. As long as the pipe remains perfect, only a certain amount of water can be put into it, according to its capacity, and once filled, there is no flow of water ; but if, when the pipe is full a small hole be made in it, the water will of course rush out at once, indicating the existence of the hole by causing a j fresh flow of water into the pipe. Now, the cable is always kept charged with electricity up to its full capacity—or, in other words, till it can take no more—and as long as it re mains perfect, there is practically no current flowing from the battery into it ; but immediately on the development of a ' fmiV., or eomtumilcatioii between the conductor of the cable and the earth, a portion of the charge escaping through the fault causi=s a fresh supply of electricity to flow from the bat tery. By having a delicate instrument fixed between the battery and the cable, this increased flow is at once made apparent. Another similar fault occurred on the 36th, fortunately un attended with any more serious consequences than in the first case. On the 39th June, the weather, which had up to that time been so fine, suddenly changed. A strong breeze sprung up j towards overling, which, by the morning of the 30th, had in- \ creased to a heavy gale. The sea was very rough indeed ; i and the frequent violent lurches ot the ship began to cause some apprehensions as to the safety of the cable. Everybody devoutly hoped that we might get through the gale without having to stop and haul back on account of a fault ; but our 1 hopes were frusirated, for just in the very hight of the gale, ' the dismal notes ot the gong announced that another fault had indicated its existence on the testing instruments. The engines were reversed, and hauling back commenced, amid the greatest excitement. At every lurch of the ship, the strain indicated on the dynamometer rose to an alarming ex tent, and as the hauling in proceeded, it seemed con tin uall.y as if nothing could prevent the breakage of the cable. Still the testing showed the fault to be outside the ship, and still the strain on the cable kept increasing, until at last, in one tremendous lurch of the ship, a whiz was heard, sending a thrill of horror into the bosom of every one on deck. The ! cable had parted ; but by the greatest good fortune the rup-1 tare occurred inside the ship, and by a most admirable prompt- I ness, the breaks were successfully put on before the broken end could run oat over the stern. The gale was still far too heavy to risk hauling in any longer, so, with not a moment's delay, the end of the cable was secured to a huge buoy, and sent adrift, to be picked up again as soon as the weather became more moderate. The remainder of that day and the whole of the next were spent in steaming about in the vicinity of the buoy, keeping as near to it as possible—the great ship continually rolling in a most ungainly fashion. On Friday, the 3d of July, the weather was suflciently ; Sue to enable us to pick up the buoy to which the cable was attached, and a very few hours suiHced to get the end of the cable on board. After hauling in about a quarter of a mile of cable, the faulty place, which had been the original cause of the stoppage, was brought on board, and very speedily the ship resumed her course. These three faults well illustrated the advantages of the system of testing employed ; for in each case, the existence 01 the fault muel have manifested itself vvithjn three minutes after it left the ship—in fact, as soon as the pressure oi the sea could force the water into the flaw. After stopping the engines, of course the "way" of the ship would carry her seven or eight hundred yards before the paying out could come to a dead stop, and this, added to perhaps a quarter of a mile run out previous to the detection of the fault, would account for the three fourths of a mile, more or less, which in each case had to be hauled in before the fault was secured. Practically, however, we may say that each of the faults was discovered immediately on its leaving the ship—and this is the great advantage of Smith's system. Neither of the faults was bad enough to prevent the most perfect communication taking place between ship and shore while the tests for local izing the fault were being made, so that the ship could give any instructions whatsoever to the shore which were con sidered necessary. On the Sth July, we experienced another heavy gale ; but as tlie testing of the cable remained perfect, the paying out was not interrupted at all. In fact, after the 3d July, nothing occurred to interfere with the progress of the work. The St. , Pierre shore end had been laid in readiness for our arrival by the William Cory, and the work of the Qreat Eastern was completed on the 13th July. The rate of paying out the cable was from five and a half to six knots per hour, the ship running five to five and a half knots. Very likely this speed might have been increased without incurring danger ; but, considering the immense size and weight of the ship, and the difficulty of , her m case of accident, it was no donbi best to k' cp .li ' i dii-in narrow limits. As to the track of the cable, it socms f om thr h a ? 41 taken that the bottom is composed, the i,i i+n "i t distance, of the fine mud usually called of very minute shells—so minute that withon' a ? n lO]" the shape is not discernible. This " oozt " t\ very best bed for a submarine cable. In fa.,i, ]i fii 1 the experience of 1866, the cable lies in it s i as free from harm as when coiled in the tan! s at *' m iiv 1 factory; and if picking up should become necessary, tlie softness of the " ooze" renders the grappling of the cable comparatively easy. The position of the present cable has one advantage over that of the English cables—namely, that it has been kept carefully off the Nevfoundland Banks, ami will therefore not be liable to the breakage by icebergs whicli Iiave already caused such expense and trouble to the English company. The cable is conducted several miles to the south of the " Great Newfoundland Bank," and then proceeds in a north westerly direction to the western side of St. Pierre Island, passing along a deep gully between th- " Green Bank " and the " St. Pierre Bank." The length of the course selected is about 3,330 knots, and the amount of cable paid (itit 3,580 knots—making about ten per cent allowance for " slack," or spare cable paid out to cover the inequalities of the bottom, and to allow of picking up, should such become necessary Without taking notice of the 800 knots from the Br gt sliore, and the 500 knots from Newfoundland, where the water is shallow, the depth varies from 1,700 to 3,700 lutlionis. the deepest part being situated in about 45 north, and iongitiuli; 43 west. Two days after the completion of the Brest and St. Pierre section, the laying of the section from St. Pierre to Boston was commenced. The cable was divided into tlu-i-e pieces, coiled respectively in tlie William Cory, k9ikm-Jm", and the Ghiltern. The course of this cable runs through BIUIIIOW vifitcT nea,r-ly the whole distance, and therefore the paying- (uit of it was not attended with that excitement which existed during the voyage from Brest to Newfoundland. It was felt tliat if even the cable should break, and be for a time lost, it would be a perfectly easy matter to grapph; for it and pick it up ; so that when, on the 30th July—through a " foii'-fhike " or tangle in the tank of the Bcanderia—the cable did adnally i;ni.p, a very few hours sufficed to drop the grappling'r'-n, haul up ihe cable, make a fresh splice, and resume operations in th.! usual way. The foul-flake was about the only thing tliat caused any considerable delay in the paying out of the cable, which was completed on Friday, the S3d July, iu the pr.-s-ence of a large number ?? spectators, incJading about a liuii-dred representatives of the American press, win) cainc down en masse, each of them siruggPng to obtain the earliest in formation. The landing place of the cable was at Duxbury, a few miles from Plymouth, celebrated as the spot whereon the pjlgrii:! Fathers first landed—a coincidence which the Am 'ricans did not fail to make the most of in the speechifying wiiich iul-lowed the completion of the work'. The length of this shorter section of trio cable was 750 knots ; adding which to the 3,580 knots from llr.'st to Bt Pierre, we have continuous submarine communication for 3,330 knots. The signals through the whole of this inimeiifie length are as distinct and readable as between any two poinls on an English land line, and can lie sent at a much greatiu-speed than the business of the line is likely to require. The signals at present consist of the oscillations of a spot of light on a screen, reflected from the mirror of a " Thomson's Eeflecting Galvanometer," as in the English cables ; but we believe this is likely to be superseded by a very delicate printing instrument, also, if we arc rightly iiifbi'aieJ, the in vention of Sir W. Thomson. Thus is completed the first direct line of submarine com munication between Europe and the United States. No doubt there will be found plenty of room for it, without injuring, in any material degree, the interests of the English com panies. We notice that tiie latter have already rediice-A their tariff, in order to keep up with the French company. This, of course, will be a great boon to a large section of the com mercial fraternity, to whom the high tariff hitherto existing has been an iasitperablo barrier to frequent communication wdth America. But, setting aside the interests of private coraTianies, which are of comparatively little consequence, we believe that the present cable will serve still more strongly to unite in sym pathy the Old World to the New, and to make it more appar ent that the interests of the two worlds are bound up together. We would fain hope that by the increase of traffic, induced by a decreased tariff', there will be found room for stiW an other cable across the Atlantic. We confess to a slight feeling of pride that this great worlc has been accomplished by Englishmen ; but waiving thiii, we rejoice that the three greatest nations of the world— England, France, and the United States—have joined in the execution of a work which cannot fail to help I'-irward in a high degree the progress of civilization. THE material growth of the South d-r'no; the last four years is strikingly shown by the cdJi-)r-.i!l= iu some of the Southern papers. The official figiiresat the Dop; rtsisciit esti mate that the cotton crop of the Southern Stales liiis year will be worth $340,000,000 ; while the total value of the exports of the South is set down at $338,500,000. At this rate, the value of Southern products is about |31'83 per head for the entire Southern population.
This article was originally published with the title "The French Atlantic Telegraph" in Scientific American 21, 19, 290 (November 1869)