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quantity discharged into the tank in any experiment, it is then necessary only to read a glass gauge attached to the tank and provided with sliding sight and vernier. For more indirect determinations of quantities of water, the laboratory contains a number of weirs of different lengths, up to four feet, a calibrated orifice tank, venturi and other water-meters, nozzles and standard orifices.
The pieces of apparatus which have been mentioned will suggest to the mind a great variety of experimental work to which they are suited, and to much of which they have actually been applied. The laboratory further contains a Pelton water-moter, a small Swain turbine, a Douglas hy Iraulic ram and a variety of dynamometers, mercury gauges, piezometer fittings, etc. There have also been placed in the laboratory a large number of finely constructed orifices and metal pieces of sundry descriptions, which were used many years ago by Uriah Boyden and James B. Francis in their famous experimental work at Lowell.
The plant which it has been sought to describe has been designed with a view to extensive further developments, important advances in which are likely to be made every year. It has been steadily taxed to its utmost capacity, both for regular class exercises and for thesis work, and fully commends itself as a substantial aid in engineering education.
PROFESSOR MERRITT asked how many hours are
Does he perspent by each student in the laboratory.
form a wide range of experiments, or only a few carefully selected ones!
PROFESSOR PORTER replied that the laboratory work is taken in connection with other work, and the exact time in the laboratory cannot be stated, but is probably about thirty hours. Each student performs a few selected experiments.
PROFESSOR GOODMAN called attention to a proposition made by Professor Lanza that the work at the engineering laboratories throughout the world should be arranged similar to that of the different astronomical observatories. Each observatory takes up and studies a certain part of the heavens, and in that way they all cover a very large field with great thoroughness. He recommends that one college take up some special class of work and do it as thoroughly as possible and communicate the results to the rest of the associated engineering laboratories. Of course, every one associated would have the benefit, not only of their own observations and results, but of others. “Some very valuable work might be done, and the trouble often lies in not knowing what has been done. It is really annoying for an observer to undertake original research work, and then find out that somebody else has done it better than himself, and that the whole of his work might have been saved, or spent in some other direction to greater profit.” He thought the subject worthy of consideration and hoped some such arrangement could be made.
PROFESSOR ROBINSON called attention to the Pitot tube as a means of measuring the flow of water, air, oil,
and natural gas.
“The only precaution to be observed in its use is to see that the joints are thoroughly tight, and that the Pitot mouth be a fairly long one, and that the side outlet be not a single one." As far as the speaker knew, the first use of the Pitol tube for measuring the velocity of air was in 1873. He had since used it extensively in measuring the velocity of the flow of natural gas in pipes.
PROFESSOR TALBOT asked the author of the paper if they made any experiments in more advanced work.
PROFESSOR PORTER explained that they did, and cited, as examples, the determination of the velocity at different points in the cross section of smooth and rough pipes, and the measuring the size of the jet issuing from a free orifice.
THE TEACHING OF GRAPHICAL METHODS IN
ENGINEERING COLLEGES AND SCHOOLS.
By H. S. HELE-SHAW, M. Inst. C. E. Harrison Professor of Engineering, University College,
When the author was invited to prepare a paper to be read before this important congress of those interested in engineering education, the subject of "The Teaching of Graphical Methods in Engineering Colleges and Schools” seemed to him to be a very desirable one for consideration.
It is necessary to commence by pointing out that the subject has apparently never yet been treated from an educational point of view, so as to comprehend its whole range in a general manner.
Graphic methods may be classified in two divisions. First, the plotting of results; second, the solution of problems.
The former of these is rarely considered worthy of any special training, as a knowledge of it is apparently regarded as capable of being acquired without any instruction.
The solution of problems, on the other hand, has of recent years received a good deal of attention, under the title of “Graphic Statics,” which is the most important, although at present only a special branch of the application of graphical operations. This branch is in many engineering schools dignified by a special course of lectures and classes, and even a special professor in the subject, while in many other schools the subject is not taught at all; and again, the opinions held by practical men, and apparently also by professors in the engineering sciences, would seem to differ in a most remarkable manner as to the value of graphical methods. The author believes that this difference of opinion is apparent and not real, and the very fact that so much attention has been devoted to the subject, in which at present there is no uniformity in the teaching nor general agreement as to methods, amply justifies the treatment of this subject before a congress such as the present, and it is with the hope that some authoritative expression of opinion may be obtained that he ventures to bring it forward, notwithstanding that there may be many present better able to deal with the matter than himself.
It will be better to deal with the two divisions in order, taking first the
PLOTTING OF RESULTS.
This method is now universal, not only in the mechanical sciences, but in almost any case where statistics of any kind are employed, as it enables results which would otherwise be difficult to grasp to be at once made clear by a simple inspection. The various methods of plotting, and the various instruments which have come into use for automatically recording such results are too familiar to need discus