JtrLY i, 1904.] 



SCIENCE. 



19 



ment with radium bromide which has been 

 recently in solution, and, therefore, sends off 

 few of the /J particles. 



Bending Moments in Rails^ for the Same 



Superstructure, under Different Types of 



Locomotives: P. H. Dudley. 



In previous communications to the academy, 

 the author presented from stremmatograph 

 tests, tabulations of the recorded unit fiber 

 stresses in the base of rails, and their dis- 

 tribution under moving locomotives and cars. 



The determination f:^om the unit fiber 

 strains, of the negative and positive bending 

 moments of the rails, due to the passing wheel 

 effects, indicates that for a definite construc- 

 tion of the superstructure of the permanent 

 way, they are independent, partially, of the 

 total load of the locomotive or car, but de- 

 pendent upon the type of each, in construction 

 of wheel base and wheel spacing, in loading 

 the foundation. 



In a series of stremmatograph tests, on the 

 New York Central and Hudson River Rail- 

 road, near mile post No. 10, December 23 and 

 30, 1899, locomotive No. 870, an eight-wheel 

 type of engine, weight 220,000 pounds, draw- 

 ing the ' Empire State Express ' of four cars, 

 weight 430,000 pounds, at speeds of 42 and 

 44 miles per hour, the average positive bend- 

 ing moments for the engine were 12.40 inch- 

 pounds, per pound of static load, for one rail, 

 constrained by a negative bending moment of 

 1.88 inch-pounds. 



The average positive bending moments for 

 the entire locomotive were 11.48 inch-pounds, 

 per pound of static load, constrained by a 

 negative bending moment of 1.71 inch-pounds. 



On December 30 locomotive No. 2032, a 

 ten-wheel type of engine, with closer wheel 

 spacing, weighing 283,900 pounds, drawing 

 the ' Southwestern Limited ' of ten cars weigh- 

 ing 910,000 pounds, at a speed of 40 miles per 

 hour, at the same place as the preceding tests, 

 the positive bending moment for the engine 

 was 10.80 inch-pounds per pound of static 

 load, for one rail, constrained by a negative 

 bending moment of 2.18 inch-pounds — a more 

 favorable result than for the eight-wheel type. 



For the entire locomotive, the positive bend- 

 ing moment — for normal tender wheels — was 



9.82 inch-pounds, for one rail, constrained by 

 a negative bending moment of 1.90 inch- 

 pounds, indicating a more favorable loading 

 of the foundation. The bending moments of 

 different types of locomotives on the same 

 superstructure are a measure of the relative 

 efficiency of the distribution of their loads to 

 the foundation; while with the same type of 

 engine the relative efficiency of the construc- 

 tion of the superstructure of the permanent 

 way can be measured. These are first bending 

 moments measured in rails under moving loco- 

 motives and cars. 



Dr. H. G. Pifford exhibited an electrometer 

 specially designed for use in measuring radio- 

 activity and showed the action of the instru- 

 ment by lantern projection. 



C. 0. Trowbridge, 



Secretary. 



DISCV8SWW AND CORRESPONDENCE. 



APPENDICITIS AND THE RACE. 



In the possible effects upon the race of sur- 

 gical intervention as a cure for disease we 

 have a curious anomaly; nothing less in fact 

 than the direct contradiction of the general 

 proposition which is at the basis of the law 

 of the survival of the fittest, viz., that what is 

 good for the individual is good for the race. 

 Some have questioned the validity of this 

 so far as its application to certain phases 

 of our social and institutional life is con- 

 cerned, but I have yet to learn of any serious 

 doubt having been cast upon it in its bearing 

 upon the organic evolution of animal forms 

 under natural conditions. Yet under the arti- 

 ficial condition of the removal of diseased 

 parts in order that the life of the individual 

 may be prolonged we have precisely this. In 

 order to give the discussion concreteness let us 

 consider the possible racial effects of the now 

 common operation for appendicitis. Since the 

 old theory of foreign lodgments — grape stones 

 and the like — in the appendix as the cause of 

 the trouble has been proven false, at least in a 

 vast majority of cases, we are forced to con- 

 sider appendicitis a disease; an inflammation 

 of a particularly serious nature, yet no more 

 accidental in its origin than are similar con- 

 gestions in other parts of the body. But 



