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16 MARINE REVIEW. [July 4, BUSINESS OF MARINE SURVEYING. Rear Admiral Sir Wm. J. L. Wharton, hydrographer to the British admiralty, has remarked that there is nothing mysteriously difficult in the art of hydrographical or marine surveying. He claims for it that it 1s an eminently practical branch of the naval profession. This it may be, but if the results obtained are to be reliable the surveyor must have special knowledge, in addition to common sense and the faculty for taking pains. Considering the subject as a phase of naval work, there is hardly any other which is more useful or interesting, as it is quite as necessary to protect the costly merchantman from hidden shoals and sunken dangers as it is to guarantee immunity from the attack of a visible enemy in the shape of an hostile warship. It might be thought, from the vigilance with which the bed of the ocean has been explored, that in these days there was very little work for survey vessels, but the duties of this kind resemble those of the proverbial housewife--they are never done. The configura- tion of the sea bed, especially within the 100 fathoms mark, is undergoing repeated change, and unless these alterations are known and notified to mariners much mischief may be done. Often, too, the government offi- cials are advised that such and such a vessel has discovered a new shoal or other uncharted danger. Very frequently, however, these "Vigias," as they are styled, are mere will-o'-the-wisps, which completely elude the - search of the survey vessels. At the same time, the fact that they cannot be located does not prove their non-existence. Rear Admiral Wharton states that experience shows that 90 per cent. of these "bugbears and most carefully transferred to the reel, and is well greased in the process. If the depth is not more than 1,000 fathoms or a little over a mile, the weight can be recovered, for 40 or 50 Ibs. is quite sufficient. For greater depths the sounding rod is used, and cylindrical iron weights of 20 or 25 lbs. with cylindrical holes cast in them through which the rod is passed. When the sea bed is reached the rod is forced into the bottom, and being hollow brings up a sample of the deposit on the ocean floor, while a slipping arrangement releases the weights which slide off the rod. A nec- essary part of the apparatus is 10 fathoms of hempen line between the wire and the rod, to act as a sort of buffer and prevent the kinking or looping of the wire. The sounding line must stop paying out as soon as the weights reach the bottom, if not, the wire kinks and breakage follows. - oes Very important, too, is the handling of the ship while soundings are taken. She must be kept head to current and if by any chance she is allowed to change her position and get broad-side-on, fouling and con- sequent breakage are almost certain. A 500 fathom length of the wire weighs 714 lbs., so that 5,000 fathoms or about 5% miles, will weigh 75 lbs. The wire pays out at the rate of 100 fathoms per minute. Thus, to take a sounding of 2,000 or 3,000 fathoms is a very expeditious matter compared with what it was in the "hempen"' days. But besides ascertain- ing depths, deep sea sounding also reveals the temperature and the nature of the deposits on the ocean floor. Surveys have demonstrated that there is a slow creep of cold water, almost icy cold in fact, along the sea bed blots" on the oceanic charts have been mistakenly placed there. Dead whales, schools of fish, wreckage, floating debris, may all and each give rise to the suggestion of a shoal or rock. Still it is unsafe to altogether discount the report of the merchant ship master. Coral reefs grow rap- idly and rise from very deep water, and hence the reported danger may be really existent. The difficulty of search is generally increased by the reporting ship being out in her longitude. This the hydrographer rec- ognizes, and he points out that within 14% miles of many coral banks it is possible to get soundings of 2,000 fathoms, so that the search for these isolated and sunken dangers is akin to looking for the needle in the hay- stack. When groping for "Vigias," fish by night or birds by day may indicate the presence of the sought for reef, but, all the same, it is un- pleasant work drifting about at night in the vicinity of even an alleged reef. The head of the British survey department suggests, therefore, that under such circumstances it is advisable to ease a kedge anchor down to a depth of about 100 fathoms, which will indicate that bottom is reached before the ship strikes on the reef. The submarine sentry, too, should be constantly towing, set to about 30 fathoms. Searching for pinnacle rocks is another protracted and oftentimes un- _ satisfactory labor. There is no royal road to discover these menaces to the navigator. Their alleged position is usually erroneous, and from their limited size, a line, or in fact, lines of soundings might fail to locate them. The plan usually followed, therefore, is to connect weights sunk from the sterns of two or more boats by a line, and then the boats steam, or are pulled slowly along parallel lines. This method of examining the sea bed is a very tedious operation, and even men as well as officers have quite an understandable aversion to "sweeping." The easiest, but perhaps the least valuable, phase of ocean survey work is deep sea sounding. For this interesting operation wire has alto- gether superseded hemp. Formerly, it was found that where a sounding was taken through a surface current, the hempen line was deflected from its downward path, and consequently, when the weight reached the bot- tom of the sea, the amount of line out was no trte index of the vertical line from the sea surface to sea bed. With the fine wire now used this disability is removed. It is usually galvanized steel wire of 20 gauge, sup- plied on drums in 5,000 fathoms length, which are sometimes in one piece but sometimes have an undesirable splice. The breaking strain of the wire is 240, lbs. and the greatest care is taken to keep the wire in good condi- tion. For this purpose the drums are hermetically sealed. and the wire A TOW OF WHALEBACK VESSELS ON THE GREAT LAKES-- STEAMER BARTLETT AND CONSORTS. from the poles towards the equator, where it is warmed; rises to the surface; is super-heated; and flows off as surface currents, of which the gulf stream is the most marked specimen, towards the poles. With re- gard to the deposits on the sea bed, these vary in proportion to distance from the shore. Fine particles of earthy matter are carried seawards by. each river, and the less weighty portions of this land waste may be carried hundreds of miles before coming to rest on the sea bed. But before this land silt ceases, it is found mixed with the various organic oozes, the minute skeletons of the microscopic organisms which inhabit the surface waters of the ocean, and whose remains form not the least appreciable portion of the deposits on the floor of the deep sea. In the most de- pressed parts of the sea bed, however, these organic remains are missing, the probability being that their descent from the surface waters, in which the live organisms make their habitat, is so slow and protracted that the - limy or flinty skeletons are dissolved before the bottom is reached. These. remotest recesses of old ocean show a floor covering constituted for thé main part of minute mineral particles--occurring as mud--which are. undoubtedly of volcanic origin--Syren & Shipping, London. While the new electric development works of the St. Lawrence Power Co. at Sheik's island, Ont., were primatily intended for the sole purpose of lighting the Cornwall canal the cOmpany will probably trans- mit power also to Montreal. Power for working the plant will be supplied by water from the Cornwall canal through a very short head race and will discharge directly into an old channel of the river St. Lawrence. The locks are provided with from six to thirteen lights and motors are provided for handling the sluice gate and for opening and closing the lock gates. The entire electrical equipment is furnished by the Bullock Electric Mnfg. Co. of Cinna a os Another steel company will soon be in position to seek a share of the business of making shapes for the construction of ships. The Dia- mond State Steel Co. of Wilmington, Del., is not now engaged in rolling a full line of shapes but they are working on a mill which will enable them to roll all the rounds, squares and flats (other than plates), to- gether with the angles, tees, channels and beams used in vessel 'con- struction, and hope to have the same ready for business within about six.months. All the shapes will be rolled' of open hearth steal aie acid and basic. >. aoe