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or under theoretical weight more than 21% per cent. "Ee Rivets to be of the en open-hearth steel. 'Tensile strength to be not less than 52,000 or more than 62,000 pounds per sq. in. Limit of phosphorus not to exceed 0.04 and limit of sulphur not to exceed 0.04 All materials to "stand work' in the ship yard without injury. The scantlings shown and described with the midship section, Fig. 1, prac- tically covers the material composing the structural strength of the ship and is governed by rules drawn up by var- ious classification societies Of such institutions Lloyds Register of British and foreign shipping may be regarded as the parent; it is by far, the most influential, for the total tonnage of all existing vessels in the world (steamers and sailing ships of 100 tons and above) almost two-thirds has been built in conformity with Lloyds rules and more than one-half continues to bear Lloyds class. On the great lakes the vessel con- struction is, greatly different to the ocean and a system is adopted to suit the traffic and facilitate in dispatch of loading and unloading the ships. New systems require the same ex- perience as older methods and it is necessary to follow up in the old way to find out any defects which may show up in the new constructon. On the lakes the Great Lakes Régis- ter was incorporated eleven years ago and has been steadily gaining until to- day it stands as the recognized author- ity as to all lake vessels and is in the hands of, and subscribed to by all the leading underwriters of the world. The prime object of classification is to establish a standard for the build- ing of vessels, and the rules laid down by the register are such as to insure a strong, well-built and seaworthy vessel, and if built under the supervision of the Register surveyors, is entered in the Register with a special mark *. The ratings of the register, are as follows, according to their structural worth and condition: *100;" --First class in every "respects and built under supervision. 100. First class in every respect and not built under supervision. 95, 90, 85, 80, according to structural worth afid condition as the examina- tion may prove. The value of classification is shown' by the fact that vessels not built under supervision are in a great many cases, built of lighter material and are of less value, than where she is built to class- ification in which case standard re- quirements are insisted upon, whereby _ velop, with very considerable -cumspection; "'TAE Marine REVIEW the owner obtains a scone and better . vess€l.and the-nnderwritér & safer risk? ; A classification society such as_ the Great' Lakés* Register is in a position to acquire experience of a most practi- cal and valuable sort; for it not only supervises the construction of many vessels in each year but has them un- der constant survey. Should any weakness or defects de- whether due to _ insufficient scantlings, bad workmanship, material or design, the circumstances is care- fully considered, and recorded. Having in this way constantly under observation many vessels the practical knowledge acquired empowers the so- ciety to start with assurance what is required and what should be avoided in a sound structural design. It is sometimes urged that the ship builder should be the best judge of what are the best methods of construction, and how much strength a ship should' have; but to build and launch a ship'does not prove hen success; it is only some years of active service in all kids of weather, that the. efficiency "Oo! the structure may be said to be proved. It is sometimes asserted that by for- mulating fixed rules, classification soci- eties tend to restrict design and hin- der progress. : Departures from the rules in the building of classed vessels are only de- barred when they tend to reduce the strength and encroach on the margin of safety found by experience to be the minimum compatible with a sound and efficient ship. ' Many high class vessels are built modifications from the methods of construction set forth in the rules, but these are usually in the direction of increased strength and efficiency. It is evident that where there is any doubt as to the efficiency of departures from usual: practice, a classification so- ciety must exercise caution and cir- representing, as it does, the general public, it is not for it to foster or originate new and untried schemes. On the ship owners contracting with the ship builder for the building of his vessel to class say, *100, the first work of the builder is to have drawn 4 set of plans upon which is shown the structural arrangement of the vessel in accordance with the instructions con-_ tained in the classification society's book of rules and the scantlings of each structural part are figured upon these plans. They are next sent to the classifica- tion society's registery where the scantlings are checked and_ special 'highest class. 4I structural requirements of the parti- cular vessel aré considered. The plans are then returned to the ship builder with the necessary cor- rections or additions required clearly marked upon them. This is the first introduction the ship has to classification society but from that day to the time of her com- pletion she is the object of their con- stant attention. Indeed throughout: her existence so long as she is classed she is periodi- cally subject to inspection. by their surveyors. Vessels are built independently of all society rules and still obtain a class, the ship owners in this case employing thoroughly capable naval architects to design their own vessels and determine the scantlings themselves. Such vessels are distinguished by the term "unclassséd" though it should | be clearly understood that an un- classed vessel is by no means necessar- ily inferior in any way to the classed one. oe Vessels built without any supervision would require to be thoroughly sur- veyed by the surveyors, and after an accurate estimate had been made of the structural worth in comparison with their own particular standard a class corresponding to one ,.of the grades of the classification society in question would be assigned to her. While it is customary for ship own- ers to have new vessels built to the highest class, it does not follow that such vessels will always maintain the Evey year surveys are held and as long as the vessel main- tains her structural strength, she main- tains her class; but as soon as she be- gins to deteriorate, and suffer reduc- tion in structural strength, her class may be reduced to 95, 90, 85 or 80 which simply means that she is now less able to carry the same deadweight as originally, her free board is in- creased until her carrying power is in accordance with her strength. To. maintain her class this can be done by carrying out certain repairs and restoring the vessel to her original class. Great Lakes Register measurements are measurements. (1) Length. L. From the forward side of the stem to the after side of the stern post measured on a water line calculated at 214 inches of free board for every foot molded depth of hold. (2) Breadth. B. Maximum molded beam. (3) . Depth." Vv, irom the upper side of the garboard strake to the top