July 7, 1911] 



SCIENCE 



23 



of friction, especially as it is met with in 

 actual practise, is a most complex and elusive 

 factor and in attempting to evaluate its effect 

 or satisfactorily account for its mutations it 

 is not safe to overlook any of the possible 

 influences affecting the final results. 



Since 1878 it has been known that Morin's 

 laws regarding friction are absolutely unre- 

 liable except within a limited range of condi- 

 tions. With heavy unit pressures between 

 contact surfaces, such as exist over the small 

 area of contact between driving wheel and 

 rail or between a brake shoe and the wheel 

 to which it is applied with the forces re- 

 quired to stop a modern passenger car under 

 present-day service conditions within a rea- 

 sonable distance, the coefficient of friction 

 may fluctuate through wide ranges, due to the 

 combined influence of pressure, relative speed 

 of contact surfaces, temperature, continued 

 rubbing and so on. For example, with cast- 

 iron brake shoes on steel-tired wheels the ef- 

 fect of speed has been found to reduce the 

 coefficient of friction from 33 per cent, when 

 just moving, to less than 10 per cent, when at 

 a speed of 60 miles per hour. 



This subject is far too broad to warrant 

 further discussion in such a communication 

 as this, but any who may be interested in 

 the experimental results obtained, and the 

 conclusions drawn therefrom, are respectfully 

 referred to papers presented before the Brit- 

 ish Institute of Mechanical Engineers, June 

 and October, 1878, and April, 1879, by Cap- 

 tain Douglas Galton, describing the classic 

 Westinghouse-Galton experiments on the 

 effect of brakes on railway trains and a paper 

 by Mr. E. A. Parke, in the Railway Gazette 

 for June 14-21, 1901, entitled "Friction of 

 Brake Shoes." Copies of the above will be 

 gladly furnished gratis on application to the 

 Westinghouse Air Brake Company, Wilmer- 

 ding, Pa. 



S. W. Dudley 



QVOTATIO^S 



ADMISSION TO HARVARD COLLEGE 



The new alternative plan of admission to 

 Harvard College, announced to the schools 



only a few months ago, was given its initial 

 test at the entrance examinations of last week. 

 The results, so far as one may judge at this 

 early date, were in every way distinctly prom- 

 ising. Over one hundred candidates for ad- 

 mission took advantage of the new provisions, 

 which seems to warrant a belief that the 

 schools already realize the possibilities of the 

 scheme as a method of getting their best 

 pupils into Harvard, and that if this year's 

 results prove satisfactory the number of appli- 

 cations for entrance under the alternative 

 arrangements will show a large increase next 

 year. 



Even more significant, moreover, is the fact 

 that of these hundred candidates more than 

 half are from schools outside New England. 

 It was precisely to this constituency — the 

 public high schools outside New England — 

 that the new plan was meant to be of service. 

 It was devised primarily as a means of ad- 

 mitting to Harvard bright boys from distant 

 schools who had pursued good four-year 

 preparatory courses, but who had not been 

 hammered into the particular grooves marked 

 out by the old entrance requirements. The 

 schools of New England, whether public or 

 private, find no very great difficulty in meet- 

 ing these requirements, and many of them, 

 doubtless, will continue to send their boya 

 along the old route. But the public high 

 schools of the middle states, the west and the 

 south have hitherto found the task of fitting 

 boys for Harvard to be much more difficult, 

 and it was to them that the framers of the 

 new admission plan hoped to afford relief. 

 These schools have responded in the most 

 encouraging fashion at the very outset. 



It will not, of course, be possible to draw 

 any definite conclusions concerning the qual- 

 ity of the students admitted under the new 

 requirements until they have passed a year or 

 two in the college, side by side with students 

 who have come to us under the old provisions ; 

 but the testimony of those who have been 

 reading the examination books indicates that 

 there is every ground for optimism in this 



