Feed water heaters; open and closed types: All sizes, for plants up to 6000 kw.; Hoppes, Conveyers: Cranes: Switchboard apparatus: Weston, General Electric, Westinghouse, Whitney, Bristol. Ground detectors. A. C. & D. C. voltmeters, ammeters, wattmeters, both indicating and integrating. Power factor indicators. Knife-switches up to 2000 amperes, both singleand double-throw and pole: Oil-switches for voltages up to 60,000, of all sizes. Overload time limit relays. Lightning arresters. Transformers: Air-blast and oil-cooled, up to 1100 kw., Current transformers, Potential transformers, Induction regulators, Arc light transformers and regulators. The templates for the switchboard construction are made to the scale of 11′′-1 ft., which is the standard adopted by most drafting rooms. The wiring diagram is not a scale drawing. An effort is made, however, to have all apparatus in the same relative position as in the plant. In addition, the department has on file a number of standard drawings of switchboard construction showing frames, bases, bus-brackets, fuse panels, etc. Also wiring diagrams for railway plants, singlephase, direct current, and also for power and lighting plants, substation wiring and construction. A complete file of catalogues and bulletins is kept to which the student has access. With these sources at his disposal and the templates in blue print form ready to be used, the student quickly learns how to combine machines and apparatus into a practical layout or design. The merit of the system is that it relieves the student of the drudgery of reducing all apparatus to scale, which would be an impossibility in the time allowed, and still retains all the valuable points to be gained from such design and the concrete expression of his ideas. By increasing the number of templates each year and showing the students the work of the previous class, the designs increase in completeness and merit. The student is interested when he sees he is producing something making him of immediate value to an employer and strives to out-do previous work. It also familiarizes the student with a standard drafting-room method and one he will undoubtedly have to learn soon after leaving college, if he does not while there. It also enables him to produce results quickly, an additional virtue which central station managers and manufacturers will place to his credit. The success of the work is mainly due to the fact that the student feels that in solving a problem based on actual conditions he is producing more than a mere design, something of tangible value. In many cases the student spends more than the required time upon this work and makes, of his own accord, additional views, such as a transverse section through the plant, a view showing coal conveyors and bunkers in detail, etc. The writer plans that the future may allow him to expand this method to the extent of having the student estimate the cost of the installation and, perhaps, to calculate the return on the investment, assuming fixed charges and a proper operating cost. To the extent that it has thus far been carried, there is no question as to its value. JOINT DISCUSSION. PROFESSOR RADTKE: I would like to say a word in regard to Professor Schuster's claim that ten is the number of students that can be taught to advantage at one time in a laboratory. I think ten should be the maximum, but as a student becomes familiar with the instruments and machines, the number can be increased. As the number increases toward the end of the college course, an instructor may have as many students inside the laboratory as it will hold. It is only essential for the beginner to have such exact provision as Professor Schuster has designated by his paper. PROFESSOR BRACKETT: We have always had a great deal of doubt about those students who naturally depend upon others to do the work for them in the laboratory. Even if only two are working in a group, there is often a tendency for one to depend upon the other for the observation. For quite a number of years I have questioned whether there ought not to be regular examinations or tests on laboratory work in addition to the reports. If reports are written outside the school it is possible for a report to be more or less excellent in form, and yet the student may have no clear understanding of what that experiment means. In my own experience I think something more is needed in the laboratory than carefully watching what is done. I think in the actual process of the work, quite an amount of questioning and crossquestioning is beneficial. Questioning may be used to develop a full comprehension of the work without telling the student what he should do. With some this is quite necessary; with others it is not even desirable. In this way laboratory work broadens to individual instruction, and that instruction is not directed to calling the student's attention to the things he should have observed, but to requiring him to make the observation himself, in order to answer the questions asked. Moreover the answers to questions asked in the laboratory may take the place of the examinations in the case of students whose experimental ability is in doubt. PROFESSOR CALDWELL: We have developed at the Ohio State University in the last few years the practice of requiring final examinations in laboratory work from all students, examinations of the same character as are required in the classroom courses, and have come to feel that this is an essential part of laboratory work. We find it best not to give the students printed forms for their tests. It is very important that they should learn to tabulate matter without having it all laid out for them in advance. Giving lectures is an excellent solution of this problem. We give no practice in central station design to our electrical engineering students, giving only design work in wiring, transformers and dynamos. We simply use the design method as an additional means of enforcing the theory of the dynamo, etc. I am, therefore, interested in this proposition of giving so much time to central station design. PROFESSOR WOOD: The question has been raised in our laboratory work at the Pennsylvania State College, and after some careful consideration we have found the best solution lies in following the student direct from classroom into the laboratory, where his special difficulties may be cleared up. It gives the instructor a chance to make sure that the students see the application of the theory. Last year I had a class of over thirty in thermodynamics. They were divided into three sections for laboratory work, and, by following up the individual men, I brought the entire class up to a more uniform standard than might have been possible had another instructor taken them in the laboratory, simply because it was individual instruction combined with classwork. When it came to examination, it was not surprising to find that the grades approximated those for laboratory and the only failures were with those who had also slighted their practicum. Does not this simple method answer many of the points raised in our discussions here? |