Iwas just closing a letter to my family where rending and crashing sound or roar of immense ceeded by a metallic sound-probably of falling then an impression of subsidence, attended by within the cabin. I knew immediately that the hurried to the starboard cabin ports, thinking way. Upon looking out I decided that I could go fore took the latter route, feeling my way along ture was filled with smoke, and it was dark. ATt'< orderly at the cabin door at the time. He ran > and reported to me that the ship had been blown the Naval Court Of Inquiry into the Maine disast( written above these photographs showing the ill· waters of Havana Harbor.-Eo.] THE work of raising the wreck of the “Maine” from ILS thIrteen years bed I Havana harbor has now progressed to such an extent that an intelligent idea may be ,had of the undertaking, the force of the explosion and permit of a consideration of the caisson or cofferdam being used in this work. The wreck originally lay in about 35 feet of water, hut the actions of the tides have raised the mud level over 5 feet, while the remains of the hull have settIed into the mud about 35 feet. As the bottom of the wreck is not less than 60 feet below sea level, lhe caisson must finally' sustain a pressure of 30 feet of water and 30 to 35 feet of mud before the hull of the vessel will be exposed either for examination or removal. The original idea of the engineers in chai'ge of the work was to pump out the water and mud to this level, to uncover the entire wreck and determine, if possible, the cause of the explosion. The recent developments of the works have made it necessary to modify these plans, because the caisson has not developed the estimated strength. The desfg'n of this caisson is somewhat of an innovation and must be considered more or less as an experiment, this being the first practical test on any large undertaking. It has not proved an entire succss, and whether the defects that have developed can be remedied and this system perfected for future use is a matter for the engineers and the owners of the patents to determine, but from the results obtained in Havana the system does not seem quite feasible, The caisson consists of twenty steel cylinders about 50 feet in diameter, constructed around the wreck in an eliptical form. Each cylinder must be considered more or less as an independent unit, rs there is a foot of space between each of the cylinders, which space has been closed in on the outside line by a 15-foot segment of a cylinder, and on the inside with a wooden pile. The cylinders are built of 150 straight, steel, interlocking staves, about 75 feet long. The staves were driven one at a time around circular forms with insufficient false work, and care was not used in the driving to keep them plumb, the result being that the top of the circle was completed sooner than the bottom, which spread in many cases as much as 24 inches, and in a few others even more. The last stave driven, which completed the cylinder had to stand the strain of .closing in the open space and drawing the bottom circle into line with the top. The interlocking jaws of the staves in some cases could not stand the strain and have splintered and cracked. As soon as all the cylinders were in place they were flled with earth dredged from the harbor. The filling of the cylinders became necessary to make the joints between the staves watertight and to prevent the steel shell from crushing under the water pressure. The strength of the caisson is derived from the earth confined within the cylinders. What this strength will be is an open question. Where the caisson would fail I fe l t the crash ot the explosion. It was a bursting, tlumc, largely metallic in its character. It was sue-ibris-a trembling and lurching motion of the vessel, \ eclipse of the electric lights and intense darkness r aine had been blown up and that she was sinking. I might be necessary for me to make my exit in that ,y the passage leading to the sllperstructure. I there-id ste a dying myself by the bulkheads. The superstrue-ring the outer entrance I met Private Anthony, the ito me, and, as I remember, apologized in SOme fashion, p and was sinking."-So testified Capt. Sigsbee before It is fitting that his dramatic story should be Telted ship as, thirteen years later, she emerges from the if tested to the breaking point is hard to say. There must be at least 10 or 15 feet of slime and soft mud in the cylinders at the level of harbor bottom. The caisson is, therefore, weakest at this point where the water pressure is greatest, so failure might be expected at about 30 or 35 feet below sea level, or at the bottom of the harbor, provided a cylinder did not become detached and forced out of place. When the caisson was completed and filled, the water was removed by degrees until a 15-foot level was reached before any signs of stress developed. At this point a thorough examination was made which showed that the various cylinders were moving, those of the side faster than those on the end; that the caisson, owing to the space between the cylinders, was not a complete unit, but composed of twenty separate parts each one acting independently. Besides this an examination below water by the divers showed that the staves of the cylinders were strained as mentioned above, and that they required immediate reinforcing. The water level was at once raised about 5 feet and maintained at the 10-foot level, while the caisson was being strengthened. Seventy-five thousand tons of stone and rock have been dumped within the caisson and banked against the cylinders. This stone, of course, has sunk into the mud and raised it from about 30 feet to 22 feet below the sea level. so the wreck to-day is buried in about 40 feet of mud. The stone fill has strengthened the caisson, but has not stopped the movement of the cylinders. Many of them are 3 to 4 feet out of plumb, inclining toward the center. The original movement, of the cy1inders, before the stone fill, under the pressure of the 10-foot water level, was 1% inches in 24 hours, while now with the rock reinforcement and with the water removed to the mud level. or about 22 feet below the sea level, the movement has been reduced to about % inch in 24 hours. The stone reinforcement encroaches upon and banks against the bow and stern of the wreck, while in the wider parts of the caisson the wreck is still entirely free. As the 40 feet of mud is being removed from the line of the wreck, the weight of the stone will force the mud from beneath the stone, thereby causing it to settle deeper and deeper into the caisson. ThIS will require additional stone reinforcing, as the reinforcing must be maintained around the top of the cylinders, to prevent them from toppling over. As the volume of the reinforcement is increased the embankment will encroach more and more upon the wreck. To correct this evil at the bow and stern it has been found necessary to place a single line of steel sheet piling as close to the wreck as practical, to retain the mud and stone against the cylinders, and prevent any further encroachment upon the wreck. This sheet piling will have to be braced to the wreck itself to withstand the pressure from the caisson, while the mud is being removed. 212 SCIENTIFIC AMERICAN September 2, 1911 A summary of the work, as it stands to-day, seems to show that the caisson is constructed of twenty separate units, which lack sufficient strength to withstand the pressure until flled; that the fll is of a nature not to withstand much pressure; that the cyllnders were strained in placing, and that all additional row of sheet piling is required to keep the reinforcement free of the wreck. The caisson has proved not only inefcient, but very expensive. The frst appropriation of half a million dollars was expended some time ago when the work was only half fnished, and another half million will be required before the work is completed. While the caisson cannot be considered an engineering success, it has permited of the removal of the remains of our “hero dead.” There are still many bodies unaccounted for and always will be, because the force of the explosion blew them free of the wreckage and into the harbor, but all the bodies confned within the wreck can and will be recovered. On August 12th the cruiser North Carolina arrived in New York harbor with the remains of Lieut. Merritt, one of the two ofcers who lost their lives. After all the remains have been recovered they will receive : ftting burial, with all the honors due brave and true men. The cause of the explosion will never be learned. If it was primarily of an external origin there wiII be no traces of it found to-day. The forward magazines have exploded and the hull is practically' cut in two. The bridge and the conning tower with part of the decks and hull have been turned completely upside down and folded back upon the main deck amid-ship, while the bow is turned completely inside out and is a mass of unrecognizable junk. For a space of about 100 feet between the wreck of. the bridge and the bow, soundings in the mud fail to show any trace of the hull. From midship to the stern the wreck Is practically intact and can be raised without difculty by building a bulkhead back of what was the bridge. The bow will have to be removed piece by piece by cutting the wreckage apart with acetyline torches. A plant for this work ha been installed, with torches that cut through the steel wreckage like a knife through cheese. This work is already under way and part of the wreckage has been removed. A wooden model of the “Maine” is in the engineer's ofce and piece by piece the model is being dismantled as the wreck itself is being cut apart. Several months must still pass before the wreck will be ready for its fnal burial in the deep waters of the sea, and the last visible sign of the wreck of the “Maine” will have been destroyed forever, excepting ollly such parts as the government may preserve for ftting memorial monuments to those who, without a moment's warning, were sent into eternity by the explosion of the ship's magazine, the cause of which will forever remain unknown. The Technical Museum of Vienna THE Technical Museum in Vienna publishes a circular stating that, in commemoration of the sixtieth anniversary of Emperor Francis Joseph's reign, A usfrian manufacturers with the assistance of the State and the City of Vienna initiated this new museum. The foundation stone was laid on June 20th, 1900, and the building, which covers an area over 20,000 square yards, and which is situated opposite the palace of Schoenbrunn, is now nearing completion and will be a lasting monument of the monarch. This Technical Museum is to demonstrate the development of industries and crafts in historical succession, also to do justice to the technical achievements of the present day, and to promote progresH In this line by periodical exhibitions. It is to be a pub\ic educational center spreading the knowledge of the scientific foundations and the national economic aim! of technical pursuits_ A considerable stock of objects has already been secured, as several large and valuable state collections, till now dispersed, are shortly to be brought together there. But many links in the chain of technical de- velopment are still missing. Therefore technical scientists, manufacturers and craftsmen of all countries are invited to co-operate in this great task and to assist the museum in procuring and selecting suitable objects. Everything pertaining to technical labor is acceptable, principally tools, machines, apparatus, models, materials, methods of working, fnished articles, as well as plans, designs, books, illustrations and manuscripts. The Austrian government has placed at the exhibition's disposal the halls of the Rotunde ("Prater") for the present storing and sifting of arriving donations. The names of donators wi be perpetuated by inscription on the gifts and in a memorial book. Further particulars can be obtained from the ofce of the Technical Museum, Vienna, I. Ebendorfer-strasse 6. Destruction of Banknotes IT WILL come as a surprise to those whose chief difculty in regard to banknotes is to be able to keep them to learn that there are yet others for whom the difficulty is how to get rid of them. Yet this is quite true in the case of those who have to destroy in bulk paper which has been used in representing money values. The difculties thus encountered in destroying such paper are well illustrated by the experience of the German imperial printers. In this case the difculties experienced are further increased by the necessity of coping with very large quantities of waste, for in addition to that arising from printing ihere is also that of stamp paper spoil'3d in the gumming as well as faulty water-marked paper. The methods previously available were three-burning, boiling and pulping. In the frst process it has been found even where a special furnace has been used, it has not infrequently happened that while the outer parts of the packets were destroyed some of the contents were not even singed. In the case of stamps or gummed paper the matter was still worse, for the packets baked together into solid blocks, the interiors of which were quite intact. In the second process the paper for deftruction is placed in iron boilers; lye is added and the contents then subjected to the prolonged action of steam. As a destructive process for small quantities this is most effectual, as is also that of pulping, a process in which the paper is cut up by revolving knives in water. In both of these cases there is, however, another dif-culty, that of disposing of the product. It cannot be easily sold, it will not pay to transport and on hand the sodden stodgy mass quickly “goes bad." The German imperial printers therefore decided to try a new way-grinding it up dry. To this end they installed a 40 horse-power Schlagkreuz mill, which by a process of hurling, crushing and tearing reduCds the paper to an almost powder like form in which it passes throuh a sieve into a collecting chamber beneath the mill ready for packing. This, however, was accompanied by a very objectionable feature, especially when dealing with gummed paper in the grinding-such a dust was created that though the workmen engaged wore protectors, j yet persistently flled and blocked their eyes and nostrils. As the work of packing was on this account not only unhealthy, unwillingly performed and also uneconomical, eforts were made to fnd some mechanical means of doing it. Simple as this had seemed at the outset, later it appeared a problem almost insurmountable. Difculty after difculty arose. Among such may be mentioned that a spiral feeder having been devised it was found that the paper would some times form into balls as solid as blocks of wood, which defed the eforts of a 20 torse-power motor to move them. Nevertheless this difculty was ultimately overcome. The imperial printers, therefore, are now to be congratulated upon possessing a machine perfect in its kind. I takes the paper, grinds it up to any size desired and bags it. Finally though the paper in this form fetches but little on account of its consequent shortness of fber, the mill is yet not only paying of Ithe initial outlay, but is also saving some $250 a year in workmen's wages. A National Bureau of Markets ON August 14th a bill was introduced in the House of Representatives providing for the establishment of a new branch of the Department of Agriculture, to be known as the “Bureau of Markets.” The duty of the proposed bureau, as defined by the bill, is to be “to make diligent investigation of the methods of marketing farm products, and especially with regard to fnding out and recommending the fairest and most direct method by which farm prodUcts may reach the consumer from the producer, by accumulating and dis-tibuting information on the subject in question and on the subject of the best methods and best markets for selling." While the language of the bill is somewhat confused, it is evident that a step of much economic signifcance is contemplated. It is the order of the day to throw light upon the mechanism of trade; and it is in harmony with the progressive ideas now being conspicuously fostered by the International Institute of Agriculture to bring scientific methods to bear upon the marketing of farm products. We believe that a work of far-reaching benefcence awaits the Bureau of Markets, and hope that Congress will see ft to give it being. Tramwars in Monte Video ACCORDING to a Consular Report, the United Electric Tramway Company of Monte Video, which was formed and registered as a British company in 1904, owns and works 131 kilometers-82 Dliles-of lines in Monte Video, with 195 motor passenger cars and 68 trailers.