November 3, 1893.] 



SCIENCE. 



241 



SCIENCE: 



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ENGINEERING LABORATORIES. 



BY B. C. CAHPENTEU, ITHACA, K. Y. 



It is the object of the present article to point out how 

 an-Engineering Laboratory can be equipped for a com- 

 paratively small expenditure. 



In discussing the subject I shall confine myself jiurely 

 to the educational features and will not consider the lab- 

 oratory as a place for investigation or solution of ad- 

 vanced engineering problems. I may also be permitted 

 to say that there are few colleges in America, perhaps in 

 the whole world, in which students, as a rule, gain suffi- 

 cient culture, or indeed have sufficient time to undertake 

 the work of investigation of engineering problems, in an 

 undergraduate course. It is only in those courses where 

 a great number of graduates are to be found that prob- 

 lems of research have any legitimate home. 



The undergraduate laboratory should be equipped so 

 as to demonstrate in a practical and convincing way the 

 principal laws or facts that the student must master in 

 order to finish his course. Its course of instruction should 

 be such as to require systematic work of the student, 

 teach him how to observe, how to use apparatus, how to 

 deduce conclusions from his mass of data and finally how 

 to make a neat and systematic report of his work. 



Having that object in view, the best methods or means 

 of execution remain to be sought. In this respect two 

 courses will be open, one, which at first may seem simpler 

 and better, consists in laying out on a single schedule all 

 the experiments that can possibly be performed by the 

 students, with the apparatus at command. Students are 

 assigned to these various experiments as they report for 

 duty. 



The other consists of a course in which are put the 

 more important experiments; every student to take in 

 turn each experiment. In laying out a system of such 

 work it will be necessary to have a series of independent 

 experiments for each term, so that the order in which they 

 are taken is immaterial. 



From personal experience I am i^ositive that the latter 

 is the only way to successfully conduct an engineering 

 laboratory, unless you are possessed of an almost infinite 

 equipment, an unlimited patience, and an entire disregard 

 of order, and even then a great number of students, work- 

 ing in as many lines, would be certain to cause vexation, 

 delay or trouble in some directiou. Besides all this the 

 amount accomplished by an individual student is general- 

 ly small, since a large part of his time has to be devoted 



to preparation, looking up apparatus, and in finding peo- 

 ple willing to lend. 



By arranging for a certain definite number of experi- 

 ments each day, which are sufficient for all the students 

 reporting that day, and repeating these day by day until 

 each student has jjerformed each experiment, the condi- 

 tions are not only more favorable for sj'stematic orderly 

 work, but a minimum amount of apparatus will be re- 

 qiiired and more efficient and better directed instruction 

 can be given. In such a case the apparatus is easily kept 

 where needed and in good order, and the student can de- 

 vote the required time purely to the experimental work. 

 I will not deny that the work of preparation and of look- 

 ing up apparatus is of benefit to the student, l)ut it is 

 not exjDerimental work and should have a place in some 

 other part of the curriculum. 



I hope 1 may be excused for devoting so much time to 

 this discussion, but I feel that it is an important matter, 

 and vital to the subject of the article. In the physical or 

 chemical laboratory I believe that the best results are ob- 

 tained by the first system, since working apparatus is 

 portable, experiments quickly arranged and the results 

 more definite and constant in character, and the same sys- 

 tem is likely to be applied to engineering, thought not 

 being given to the facts, that engineering constants are 

 seldom more than coefficients, and the value is affected by 

 the method used in testing. In many engineering exj^eri- 

 ments the method is of equal or greater importance than 

 the results. 



For the reasons just stated I would advise a limited 

 number of experiments each term and require each stu- 

 dent to take the course as laid out. I am positive tliat 

 the better instruction obtained will more than offset any 

 loss due to the want of selection. 



The nature of these experiments must depend upon the 

 apparatus, but I will, however, refer to a course which 

 might be pursued in case the equipment was extremelj' 

 small. Suppose, first, the course to be in civil engineer- 

 ing, in which case the laboratory work will relate prin- 

 cipally to strength of materials and hydraulics, field 

 work and astronomy, the two latter will not, however, be 

 included in this laboralory course. The apparatus needed 

 might be certainly as much as could be purchased, but 

 one testing machine of 50,000 pounds capacitj', arranged 

 for testing in tension, compression and transverse, a cement 

 testing machine, a small drop of 100 pounds falling ten 

 feet, and a wooden beam twenty feet long and four by 

 eight inches in dimensions, will be found to be sufficient 

 apparatus to keep four experiments, two men at each, in 

 operation the entire time. The cost of such apparatus 

 will probably not exceed $1,000 and possibly might be 

 less. 



The experiments that might be performed are almost 

 infinite in variety in the line of strength of materials, 

 and the students could not only obtain skill but also 

 valuable knowledge respecting the properties of mate- 

 rials. 



Some of the most interesting experiments are performed 

 with little or no apparatus, as, for instance, by loading a 

 beam in different ways and studj'ing the effect on the 

 elastic cam produced by the load in various positions. 



For hydraulics, little is needed but what can easily be 

 made by resident mechanics, excepting tanks and weigh- 

 ing scales. Weir notches and hook gauges are readily 

 made and ensure materials for an almost endless variety 

 of experiments. 



Small water motors and pumps are quite inexpensive, 

 so that probably for $500 an equipment that will give six 

 experiments and keep twelve men at work constantly can 

 be had. If a student could spend six hours a week, which 

 is about the amount required to complete a single experi- 



