and allowances to be made for knots, seasoning checks, and decay. Now taking up the different materials as cast iron, wrought iron, steel, in turn, it will be found the text-book can be used much. more effectively. Every student now has some experience to be appealed to, and he is gradually beginning to think and express himself in the technical terms of strength and elasticity. Tests are now made only to illustrate some new method of testing or some peculiar property. Thus, a complete tensile test. is made on a finished specimen of steel using an electric contact micrometer (Fig. 17). The broken ends of the steel or wrought iron specimens tested early in the course (Fig. 1), are retested to show the increase in strength due to rest after cold-working. A torsion test on steel is made with the Thurston Autographic machine (Fig. 18a), another test on a specimen from the same bar to show the exaltation of the FIG. 18. elastic limit (Fig. 18b), and a third (Fig. 18c), to show that the elastic field is fairly constant, and that raising the elastic limit in one direction reduces it in the other. DISCUSSION.* Mr. Hibbard. Mr. Goss. MR. H. WADE HIBBARD.-There is one criticism that it seems to me might be made, which criticism is directed at the methods which have been necessitated, perhaps, by the increase in the numbers of students taking laboratory courses of this sort. I know we shall all remember the Presidential Address this evening, and I hope that we shall give particular remembrance to the thoughts that Dr. Dudley brought out with regard to real education. It seems to me that in the multiplicity of experiments, in the desire on the part of the experimental laboratories to get a large number of experiments, somewhat varied, in the blank forms and careful directions, that the principle of education—real education may be somewhat obscured. This, according to our President, is not the pumping into the student's mind of a large, amount of information, but the leading out from that student's mind, cultivating in that student's mind, the ability to reason for himself, to be ingenious and to plan for himself, and scheme out his methods for making experiments himself. That, of course, means that not so many experiments can be performed by students, but what they do perform they get in a fashion that gives them education in experimental methods, and in the ways of thinking as testing engineers. MR. W. F. M. Goss.-The modern engineering laboratory contains apparatus of many different kinds. It has its steam engines, internal combustion engine, hydraulic apparatus and its machinery for testing materials. As I have followed the work of students along these different lines in a fairly busy laboratory, I have often been impressed with the fac that among them all none so well satisfy the requirements for the development of young men, as the material testing. Work along this line lends itself most readily to the instruction of students. In the department of *Joint discussion of the two preceding papers, namely, "A Laboratory Course in Testing Materials of Construction," by W. K. Hatt, and "An Elementary Course in Properties of Materials," by G. L. Christensen. |