special conditions, this form will be found serviceable in the writing of nearly every kind of laboratory report.

1. Object. This division should consist of a clear, full, and concise statement of the object, preferably in the form of a simple declarative sentence. Since the report is not written until after the test has been performed, the statement should be put in the past tense; e. g.,

"The object of this test was to determine the steam consumption of a Brownell 10 X 12 engine."

2. Theory. This division should contain a general statement of the data to be obtained in such a test, together with the fundamental principles on which the test depends. For example, the second paragraph of the report indicated above might begin as follows:

"In testing for steam consumption, the chief data to be obtained are (a) the horsepower of the engine, and (b) the weight of the steam passing through the cylinder in a given time."

Where formulas are to be applied in the test, they should be given in this part of the report.

Since the discussion deals with general theory, this section of the report should be expressed in the present tense.

3. Apparatus.-The apparatus used should be described, with emphasis on new apparatus and on special devices used in the particular test in question. At the beginning of the section, the various pieces of apparatus should be enumerated. New and special pieces may then be described in detail.

In so far as this part of the report deals with particular apparatus, it should be put in the past tense; e. g.,

"The apparatus used in this test consisted of the following," etc.

4. Procedure. This section contains an account of what was done in carrying out the successive parts of the test. Care should be taken to omit preliminary and non-essential operations, and to follow the actual order in which the work was done.

The narrative should be impersonal, and should be given in the past tense and the passive voice; e. g.,

"Readings were taken at intervals of five minutes,” etc.

5. Results. (a) Summary of results: Conclusions drawn from the data should be stated briefly and clearly. In some cases it may be desirable to compare them with results obtained in other tests. (b) Curves. (c) Sample calculations: These may be brief, but they should be typical of the mathematical processes involved. (d) Data: The data should be presented on special paper designed for the purpose, and should be arranged in tabular form and in parallel columns. 6. Sketches.

7. Original Data.-Rough notes taken during the test should be submitted from time to time as evidence of the accuracy with which observations were made. If a log book is kept, it will answer the purpose.

Respectfully submitted,

C. W. PARK, Chairman.

REPORT OF COMMITTEE NO. 13, MECHANICS

AND HYDRAULICS.

Topic: Main Objectives in Teaching These Subjects.

O. H. Basquin, Chairman, Northwestern University; J. E. Boyd, The Ohio State University; C. H. Burnside, Columbia University; H. F. Moore, University of Illinois; C. I. Corp, University of Wisconsin.

1. The courses to which this report particularly relates are those of mechanics, strength of materials, and hydraulics; portions of the report may be considered to be of more general application. Preceding mechanics, the student has had an introduction to this subject as a part of general physics; he has had a course in calculus, or takes that study along with mechanics.

2. In each of the three courses considered, one of the main objectives is to give the student a working knowledge of fundamental facts and principles. An engineer needs a working knowledge of essentials rather than a superficial knowledge of a wide range of information. One who is not confident of the essential accuracy of his knowledge does not readily gain the confidence of others, and rarely maintains his own self-respect.

3. The course in mechanics makes extended use of facts and principles which the student should have acquired in physics, calculus, geometry, algebra, and arithmetic. A first duty of the instructor in mechanics is to put the essential parts of these prerequisite subjects into working order; and this instructor should not look upon his task as that of doing another man's work. One can rarely secure thorough knowledge of any fact on first meeting it; the early courses cannot give the wealth of illustration and the new points of view that are available in later courses; and repetition at intervals is a particularly efficient method of learning.

4. Similar suggestions might be made with respect to strength of materials and to hydraulics; in fact, with respect

to almost any course of an engineering program. The objective is to put the essential facts and principles into such form that they can be used by the student with readiness, accuracy, and certainty.

5. The student must become proficient in the solution of problems. Under proper circumstances, it is believed that some of this problem work should be done under supervision, for the purpose of giving the student a start in logical thinking and in orderly, accurate, and economical methods. This suggestion is based upon the principle that it is easier to start a right habit at the beginning than to correct a wrong one. The chief danger in adopting this suggestion is that the instructor may not give the proper kind of supervision: he must not be dictatorial but must develop initiative; his work is to make the student do his own thinking in a proper mannernot to think for the student; when the student has acquired this ability he needs no further supervision.

6. Mechanics is an experimental science; experimental work should accompany each course under consideration. A blind person cannot understand the theory of painting because he cannot experience the sensations of color. In a similar way, a student cannot comprehend mechanics unless he can experiment, because it is only through experiment that he obtains the fundamental concepts upon which the subject is based. The student needs experiments to illustrate in a concrete way some of the important derived facts that are developed in theory, to show their degree of accuracy, and to point out their limitations. In this connection it is to be noted that such experiments, to be most useful, should be so correlated with the class instruction that these concepts and illustrations will be given to the student by the laboratory work at appropriate stages in the development of theory in the class room.

7. The successful engineer is an accurate observer and he draws conclusions from data directly obtained from observed facts. Laboratory work is particularly useful in developing habits of observation on the part of the student. A text-book

problem gives a more or less definite key to its solution through its selection of data: this is not the case with problems that arise in the laboratory; here the student has a chance to apply his knowledge to facts that he obtains through his own selection and observation. The instructor who deprives the student of this experience by giving too minute instructions, denies him an excellent opportunity to develop that resourcefulness and straight-forward thinking, which an engineer must have when facing practical problems.

8. Since an act of observation is not complete until the student has recorded and explained what he has observed, the report is an essential part of laboratory work. It serves to fix the observed facts in the student's mind in an orderly sequence and in an emphatic manner, while it enforces thought upon unselected data. While the report should be in good form, the student should be encouraged to limit its contents to essential matter.

9. Many of the principles of engineering are based upon assumptions, while approximations are often made in analyses. Since the student should be taught to think logically, it is of prime importance that the instructor make a sharp distinction between fact and assumption, between strict analysis and approximation. In reaching conclusions, analyses should be used whose refinement is appropriate to the data obtainable, and the limitations of the conclusions should be recognized. These suggestions relate to the development of intellectual integrity; it is not suggested that these matters be given such undue prominence as to confuse the student, but it is highly important that the instructor appreciate them and make them clear to the student on appropriate occasions.

10. The engineer needs a fluent command of good and forceful English. This is largely a matter of habit, and its development can be brought about most effectively by the coöperation of all instructors to this end. Every student should acquire habits of punctuality in the prompt completion of every duty, of numerical accuracy of acceptable grade, of the presentation of work in good form, and of economical methods of