508 



SCIENCE 



[N. S. Vol. XXXIX. No. 1005 



energy as principles and state that mechanics 

 can not be based upon the principles of the 

 conservation of energy and of momentum 

 alone ? 



What about the law itself? The first part of 

 the law is clear. ' ' To every aetion there is an 

 equal and opposite reaction ' ' is nothing but New- 

 ton 's third law of motion. The word "or" leads 

 us to think that the second part means the same 

 thing as the first part. 



Had Profesor Rettger examined my book 

 with greater care he would have noticed that 

 I have used the term " reaction " in a slightly 

 different sense and that with this difference 

 the "first part" is not at all Newton's third 

 law but has the same meaning as the " second 

 part," and that the two " parts " are only two 

 different forms of the statics principle. Further 

 he would have seen that the first form is not 

 made use of, the entire work being based upon 

 the second form alone, and would not have 

 charged me of having assumed Newton's third 

 law in addition to the one I have introduced. 

 The first form is left out entirely in the 

 papers which I published on the subject.^ In 

 one of these papers I have even shown that 

 Newton's third law is a direct consequence 

 of the second form. 



I have postulated the following principle, 

 which I have called the action-principle: 



The sum of all the actions to which a iody 

 or a part of a hody is subject at any instant 

 vanishes : 



2^ = 0. 



Then I have classified and defined the 

 different forms of action. On this principle I 

 have based my treatment of mechanics, and 

 claim that I have given it a degree of unity 

 and logical continuity which is not common 

 to treatirients of elementary mechanics. This 

 is made possible by the simplicity and flexi- 

 bility of the action-principle, which is easily 

 grasped by the beginner, yet conveys a depth 



1 ' ' On a Progressive Development of the Prin- 

 ciples of Mechanics, ' ' Physical Review, May, 1913 ; 

 ' ' On a Progressive Development of Mechanics 

 Based Upon a New Form of the Fundamental 

 Principle of the Science," American Journal of 

 Science, February, 1914. 



of meaning and breadth of application com- 

 mensurate with the knowledge and ability of 

 the student. 



Besides this pedagogical advantage my 

 treatment involves a point of view which is in 

 harmony with our present ideas of dynamical 

 phenomena, as it is shown in my recent paper 

 on the subject.^ H. M. Dadourian 



Yale TjNrvEBsiTY 



A KEW METHOD OF COOPERATION AMONG 

 UNIVERSITIES 



In April, 1910, was formed at Kansas City, 

 Missouri, the Missouri Valley Conference of 

 Heads and Governing Boards of Universities. 

 The Conference embraced, however, only the 

 institutions up to that time belonging to the 

 Missouri Valley Conference for athletic pur- 

 poses. There have been many conferences 

 and associations of professors of universities 

 and presidents of universities, or both, and 

 there have been conferences of school boards 

 representing the public schools in various- 

 cities, but this is probably the first attempt 

 on the part of university governing boards to 

 accomplish a general understanding and co- 

 operation in regard to matters affecting insti- 

 tutions similarly situated. The conference 

 arose over the matter of intercollegiate foot- 

 ball, the question so fruitful of controversy 

 and discussion. The reason for the conference 

 was as follows: There had been introduced 

 into the board of regents of the University o£ 

 Kansas a resolution abolishing intercollegiate 

 football. The vote was a tie and the motion 

 was lost. The question was brought up again 

 and after thorough discussion it was agreed 

 by the board of regents of the University of 

 Kansas that it was unwise to attempt to settle 

 that question in one university alone and that 

 all of the universities of the then existing 

 Missouri Valley Conference, through their 

 heads and governing boards, should be asked 

 to meet in a general conference at Kansas 

 City in April, 1910. It was at the time of 

 large and pointed discussion and criticism of 

 intercollegiate football and after the matter 

 had been clearly laid before the institutions 

 most interested all of them accepted the invi- 



2 Loc. cit. 



