894 



SCIENCE 



[N. S. Vol. XXXIII. No. 



To the boy who enters the engineering col- 

 lege fresh from high school, the reading of 

 Arnold's " Sweetness and Light," " Hebraism 

 and Hellenism," etc., is both stimulating and 

 broadening. It forces the freshman to think, 

 to sum up his own ideas concerning his rela- 

 tion to life and the world about him; and 

 perhaps, before he realizes it, his outlook on 

 life has widened. Arnold teaches him to 

 value himself for what he is, to understand 

 what ideal perfection is, to attempt, specialist 

 though he be, to prepare himself for a well- 

 balanced life. The results of Arnold's teach- 

 ing I have found in impromptu paragraphs 

 on " My Aim in Life," written in the composi- 

 tion class. Here, back of an occasional ob- 

 vious effort to write what might please the 

 instructor, I have seen evidence of a sincere 

 desire on the student's part to be not only a 

 perfect engineer, but a well-rounded man as 

 well. 



The transition to Huxley is made through 

 his controversy with Arnold over the means 

 of getting a cultural education. In Percival 

 and Jelliffe's " Specimens of Exposition and 

 Argument " which the men use in their com- 

 position course, is Huxley's address at the 

 opening of Sir Josiah Mason's Scientific Col- 

 lege in Birmingham. Arnold's reply is in 

 Gates's " Selections." This controversy gives 

 the freshman a good idea of difFerent views 

 of education, especially of scientific education, 

 and paves the way for Huxley's talks on " A 

 Liberal Education," "Principal Subjects of 

 Education " and " On Improving Natural 

 Knowledge." 



The subject-matter and structure of Hiix- 

 ley's addresses appeal to the freshman engi- 

 neer. This part of the course fits in particu- 

 larly well with the exposition work in compo- 

 sition. The student learns "how to fit his 

 material to his audience, how to outline 

 clearly, how to say things most concisely and 

 in the strongest way; and the fact which the 

 autobiography gives us, that Huxley at first 

 detested writing and speaking, encourages the 

 freshman to emulate Huxley's example and 

 master his mother tongue, that he, too, may 

 best put his ideas before others. As to the 



subject-matter, what is better fitted to interest 

 the scientific student than "On a Piece of 

 Chalk," " Coral and Coral Reefs " or " The 

 Physical Basis of Life"? Such essays open 

 up for him the great facts of nature which 

 have come in with the " new knowledge." 



The fact that this course, joined to the 

 course in practical composition (which is 

 another story), is required of all engineering 

 freshmen and that it is the only course of its 

 kind which they will ever get in college, makes 

 the question of proper subject-matter of vital 

 importance. I should welcome criticism and 

 suggestions. 



Charles Washburn Nichols 



The University of Minnesota, 

 December 27, 1910 



J A KINETIC THEORY OF GRAVITATION 



To THE Editor of Science: In reading the 

 article entitled " A Kinetic Theory of Gravi- 

 tation," which was published by Dr. Brush in 

 Science for March 10, I was at once struck 

 with what seemed to me a fallacy in an illus- 

 tration given early in the discussion. Per- 

 haps the point at issue has been sufficiently 

 discussed by Dr. Kent in Science for April 

 21; but since it presented itself to me some- 

 what differently it may not be out of place to 

 give my line of reasoning. 



I refer to the consideration by Dr. Brush of 

 the case of the transportation of a one-pound 

 mass from the surface of the earth to a point 

 of equilibrium between the earth and the 

 moon, at which point there would be no tend- 

 ency for the body to move either toward the 

 earth or toward the moon. As I understand 

 the argument of Dr. Brush he assumes that in 

 this case there is an apparent disappearance 

 of energy; that there is no gain in the poten- 

 tial energy of the system caused by raising 

 this body from the surface of the earth to the 

 position of equilibrium and that there is, so 

 to speak, nothing to show for the work done 

 in so raising it. 



The point that Dr. Brush seems to have 

 overlooked is that attraction between two 

 bodies is mutual. If the pound mass in the 

 position of equilibrium is attracted by earth 



