Sayfadaki görseller
PDF
ePub

memoirs or from abstracts, more especially with the work of the Froudes. Some attention should also be given to propulsion by sails.

In connection with the study of propulsion, the students should work out a general problem, determining the size and form of a ship for a specific purpose ; for example, to carry a given cargo a certain distance at a given speed. There is a distinct educational value in making a preliminary solution of the problem by a logical method like that proposed by Naval Constructor Woodward, U. S. N. The main dimensions thus obtained are then to be modified by advice of the instructor and will take the place of the data usually assumed by the designer, without such a preliminary solution, as the basis of the design. The student will then both understand and appreciate the tentative methods commonly employed.

Together with the calculation of displacement and resistance, the student should select the scantling for the ship and get the work ready for calculating weight and strength. In some schools of naval architecture the calculations for weight and strength are made in connection with such a problem and the work is considered to form the design of a ship. But a design cannot be intelligently made before the calculations of weight and strength are understood; consequently such an arrangement makes it necessary to give a preliminary problem in that line, thus duplicating work that must always be abridged when given for sake of instruction, and which must in any case appear tedious as compared with other work in the course. The reason for giving a design appears to be largely that

a

the business of a naval architect is to design ships and that the graduate of a school of naval architecture should show that he is fit for the business of his profession. In other branches of engineering such an idea has fortunately disappeared and we have instead the correct idea, that the graduate of a technical school is a young man who has had certain advantages fitting him to begin and to learn his profession. This is the more important in the case of naval architecture, as the design of a ship is a work requiring the matured skill and experience of one who has mastered his profession and who has at his command a staff of draughtsmen and computers. It is believed that the order recommended will most quickly and efficiently give the training which can and should be given in a school, and that it will give the graduate of the school a more modest and just appreciation of his status, at the time when his profession is all before him.

At some time during the course, probably toward the end, instruction should be given touching drainage and ventilation, and concerning armor and armament. The general principles, so far as they have been developed, should be clearly stated and details should be given to illustrate and enforce them. Adjustments of the compass should be taught, though such matter belongs rather to the navigation than the construction of a ship; but the constructor may greatly aid or hinder the proper placing or adjusting of the compasses, and not infrequently he may be called on to take the entire responsibility, especially in merchant work. In connection with the study of the compass, arrangements may be made to give practice in adjustment either on board some ship, or more conveniently, on a compass so mounted that it can be influenced by permanent and temporary magnetism, and may beswung to determine and compensate the effect of such magnetism. Other such work, of the nature of laboratory practice, may be devised in connection with some of the subjects taught, and will add to the interest of the instruction; but the students, in common with all students of a technical school, will have a thorough training in laboratory methods, which is the more fortunaté as much of the work in naval architecture is not susceptible of treatment in a laboratory. Again, it is more important that students should learn the methods of the laboratory and that they should do something thoroughly, than that they should do some specific thing. As far as possible, however, all laboratory work should be bent to the general trend of the work in a given course, even in a subject like applied mechanics, which is common to all engineering courses. A student of naval architecture will take a more lively interest in experiments on riveting which relate to shipbuilding or boiler-making than in those which relate to bridge work, and yet the latter cannot properly be treated with neglect.

The one prominent application of the laboratory method in naval architecture, is the investigation of resistance by towing a model of a proposed ship in a tank. Such work to be of value must be done in connection with construction of ships, and the ships, when completed, should be given adequate progression speed trials. The tests of the models and the ships form together a work of the greatest importance in the advance of the theory and art of ship building. Tests on models only are useless or misleading. Consequently it cannot be expected that a tank for towing models can be advantageously maintained as part of a school when instruction is the main object. And yet there is no doubt that students of naval architecture would find much advantage in taking part in the work of such a tank.

If a mould loft is accessible, or if a floor that can be used for such a purpose is at hand, practice can be given in mould loft work, and will be found to be both interesting and instructive to the students. It has been found that students who are familiar at once with descriptive geometry and with ship lines can get a practical mastery of mould loft work in a week or ten days of vacation work.

The naval constructor should know enough of the use of the level and transit, to use them freely in laying out a yard, in making changes in a yard, and in laying out and checking the building of the ship, the launching ways or the hull itself. As an example it has been found in a certain yard, that successful launches can be made under conditions usually considered hazardous, by the simple device of making sure that the launching ways are true and properly supported.

A COURSE IN MUNICIPAL AND SANITARY

ENGINEERING.

BY ARTHUR N. TALBOT, Professor of Municipal and Sanitary Engineering, University of Illinois,

Champaign, Ill.

The growth of population in the cities of the United States in the last twenty years has been very large. The necessity for the construction of municipal public works, especially in the smaller cities, has increased even more rapidly than has the urban population, and the municipalities have not been able to keep up with the demands incident to this growth. Present conditions indicate that the development of cities is to be greater in the future than in the past. Especially in

. the West is such future development probable, and in this region the present condition of public works is not only behind the material development, but there is a greater necessity for increased and improved construction.

In the same period of time there has been a marked advance in the knowledge of those matters pertaining to the health and comfort of urban communities which are now included in sanitary engineering.

These conditions explain the necessity for a course of study which shall prepare the student for the duties of engineer of public works of cities.

The writer is not an extremist on the question of the specialization of engineering courses. He believes that the primary object of engineering education is the development and discipline of the student along engineering lines, and that professional specialization

( 292 )

« ÖncekiDevam »