18 



THE CIVIL Ei^GINElilR AND ARCHITii:C c'S JOURNAL. 



[J 



AN. 



temple of Jupiter Parhellenius at Aizani, described by Texier. The 

 department of Rom,in arcliitcctiire, as M. Canina's more immediate 

 and autoptic province, is treated ivitll a detail descending into tlie 

 slightest miniitia; of theory and practice. The great number of 2oG 

 plates is devoted to this portion of the work. 



Narratirf 0/ the Recorery of H. M. S. Gorgon. By Astlev Cooper 

 Key, Coiuinauder, R.N. Loudon ; Smith, lilder, and Co. 1847. 8vo., 

 pp. 113. 



During tlie military operations of the Buenos Ayrean army against 

 Monte Video, in 1813, a violent gale occurred, by which H. M. steam-ship 

 Gorgon, part of the British squadron stationed in ihe Kiver I'lale, was 

 driven ashore. The present work contains a clear, interesting, and most 

 minute account of the mechanical means by wliich tlie vessel was rescued 

 from her perilous position. The didicnlties contended against were so 

 formidable, and the ingenuity and energy displayed in overcoming them so 

 great, that the account given by an officer of the vessel, who appears to 

 have had an important share in the work, possesses a general interest. To 

 the naval oflicer and engineer, however, the narrative will appear of much 

 more importance than an interesting story : the accurate and detailed ex- 

 planation of all the operations and apparratus, and the record of their com- 

 parative efiiciency, brings this work into that class of circumstantial pub- 

 lications which the two professions have learned to consider invaluable. 

 It may be added that the present moment seems happily chosen for pub. 

 lishing this book, when general attention is attracted to the fate of the 

 Great Britain. 



Before analysing the part of the work referring to the recovery of the 

 ship, we may be doing some service by calling attention to certain defects 

 of construction, which Lieut. Key assigns as contributing causes of the 

 stranding of the Gorgon; they are these — 1st, insufficiency of engine- 

 power for extraordinary emergencies ; 2nd, the want of uncdiors and cables 

 in number and size proportioned to those of sailing vessels ; 3rd, Ihe 

 absence of a niizeri-mast. Under the first head, our author well remarks 

 that a steam ship ought to have power sufficient for extraordinary as well 

 as ordinary occasions. The Gorgon had not during the gale sufiicieat 

 power to steam into deep water, and barely gained steerage way. Again, 

 the sails could not be used to bring the vessel to the wind, for from the 

 position of the mainmast, the effect of the mnin trysail was neutralised by 

 the action of the wind on the paddle-boxes, which were as much before 

 tlie centre of the ship as the trysail was abaft it: had there been a mizen- 

 mast, its sail would have had leverage to turn the vessel. 



In order to understand the subsequent operations, we must consider the 

 position of the vessel after stranding. She was found ou examination 

 afterthe storm, to have run hind foremost into a sand bank, 13 feet high. 

 A few feet of her stern were still in the water, but by far the greater part 

 <>/ the ship rested on — and, forward, was imbedded in — the sand. The 

 idea of getting the ship from such a position, without taking her engines 

 out, when first expressed by her commanding officer, Capt. Hotham, sub- 

 jected him to the pleasant suspicion of labouring under a tit of insanity. 



The means of the recovery were mainly these : the formation of a docki 

 by the excavation of the sand for a distance of twenty feet from Ihe vessel; 

 the application of large screws on the beach, partly to raise her vertically 

 and iiartly to start her forward ; the lashing of buoyant caissons to the 

 ship's bottom to lighten her ; the haulage by cables attached to the vessel 

 worked by capstans on the beach ; and by other cables attached to anchors 

 in deep water, and worked by the ship's engines. 



The first of these operations was by far the most arduous, and was con- 

 tinued almost incessantly during the whole time occupied in recovering 

 the vessel— up%vards of five months. From the loose nature of the sand 

 and effect of the tides, the banks of the dock frequently gave way, and 

 the labour of a month was undone in a few hours. A great part of the 

 excavations were effected manually, but an ingenious machine, constructed 

 upon the spot, was also used for the same purpose. To a fulcrum on 

 either side of a barge was fixed a long lever, with a capacious mud-bag at 

 the end of it; the mouth of the bag being kept open by a hoop, to which 

 chains were attached to drag it through the sand : the chains were worked 

 by wiuclifs in the extremity of the barge. By these simple means, 

 4^ tons were cleared away in an hour, and the apparatus was sometimes 

 kept in use night and day for several weeks together. The great difficulty 

 however was not to get the mud out, but to keep it out. A resident civil 

 engineer undertook the constructiwi of a dam of piles of three-inch plank, 

 dlriveQ /our or/c«y£e< into the sand;— the first high tide carried them all 



away. Another dam, however, constructed on the starboard side of the 

 vessel, where the water had little force, answered its purpose tolerably 

 well, Ihe piles forming it being driven deeply into the sand. A complete 

 bulwark against incursions of the sand was subsequently constructed by 

 mooring alongside Ihe vessel three large iron boats, which together formed 

 a breakwater 120 feet in length. 



The application of pressure by means of large screws to force the vessel 

 forward seems lo have been a novel one. The employment of vertical 

 screws in transporting and launching vessels had been already practised, 

 but here for the first time screws were used to propel the ship as well as 

 raise it. Only a limited number of cables could be obtained for hauling, 

 and the aggregate strain which these would bear without breaking was 

 totally inadequate to move the ponderous mass to which they were attached. 

 The application of the screws therefore effected that which without them 

 would have been impracticable. The great difficulty was to obtain a firm 

 purchase for them, as the abutments on the loose foundation, against which 

 they acted, were liable to give way. This difficulty was overcome by im- 

 bedding enormous blocks of wood deep in the sand, so as to distribute the 

 back-pressure of the screws over a large surface. 



Our author calculates that a force of about 550 tons was applied to 

 start the ship forward — 300 tons from the pressure of screws, and the re- 

 mainder from the tension of cables. The screws were all inclined to the 

 horizontal, so that their force was partly vertical, partly horizontal. The 

 pressure resolved in the former direction was about 130 tons ; in addition to 

 tills upward force there were 470 tons arising from the buoyancy of large 

 camels, caissons, boilers, tanks, and barrels attached to the ship's bottom ; 

 so that the total force tending to raise Ihe ship was about COO tons. We 

 cannot pursue Ihe narrative further than to state that by these means, after 

 nearly half a year of forethought and invention on the part of the officers, 

 and unceasing industry on the part of the men (nearly 300 in all), the vessel 

 was restored to her native element, without any injury, unless we ex- 

 cept the following very trivial one, which we allude to merely because it 

 arose from a cause worthy of the attention of the practical engineer : — 



*■ At one of our previous attempts to move the ship, when no impressioa 

 could be made on lier, beyond giving her a lift lo port of about 10°, the 

 sudden heel had fractured the waste water and injection pipes, thereby 

 showing that the ship must be slightly strained somewhere ; but, as these 

 pipes are of cast iron and are rigidly bolted lo the ship's side, a very slight 

 jerk would be sufficient to break them ; soon afterwards, however, when 

 the ship was brought upright by the camels, Ihe broken parts resumed their 

 original position, and so exactly, that Ihe fracture could not be discovered 

 without very minute inspection, and in that slate were easily and eliicienlly 

 repaired ; this showed what a trifling strain was sufficient lo break these 

 pipes, and it would appear that in the event of a steamer taking the ground 

 under any circumslances, should she not be so strongly built as the Gorgon, 

 these vital parts of Ihe engine woukl be liable to serious injury — surely a 

 remedy for this might readily be found, by fitting these pipes with a slid- 

 ing joint, and also, instead of bolting the extremities to the ship's side, less 

 liability to fracture would be incurred, by fitting it with a slide and flange, 

 giving the extremity of the pipe free motion in every direction, and making 

 Ihe diameter of the hole in the ship's side, something less than that of the 

 pipe." 



The principal practical value of this book arises from the minuteness 

 with which the information is given. There are eighteen lithographic 

 plates, and every piece of apparatus of any importance is carefully de 

 lineated and described in a detailed manner. The information respecting 

 admeasurements also is generally complete, and the author seems to pos- 

 sess considerable knowledge of theoretical mechanics. 



TIte Colosseum, St. Peter's, The Pantheon, The Forum ; drawn and en- 

 grared 63/ DoMENiCHo Amici, iMembro d'Onore della Congregazione de 

 Virtuosi al Pantheon. Size 23 inches by 19 inches. 



These splendid engravings, illustrative of Rome, have just been imported 

 into this country from Rome, by Messrs. Groombridg^ and Sons ; they are 

 admirably drawn aud engraved in Ihe line manner, by Domenicho Amici, 

 an Italian engraver of considerable merit ; they are the commencement of 

 a series. The above four prints are well suited to the studio of the archi- 

 tect. 



A Praetical Treatise on Peripective Simplified. By Georoe Pt»S. 

 Weale, 1840. 12mo. pp. 103. Lithographic plates. 



This treatise is addressed to those who wish to acquire only a limited 

 knowledge of perspective, but to acquire that little correctly. The object 

 of the author has been to reader the work as concise as possible, and to 



