THE WORLD'S ADVANCE 



151 



A Typical Iron Bridge Crossing Railroad Tracks, Which Ultimately Became Weakened by the Corrosive 



Effects of Locomotive Smoke. 



A very novel way of solving the prob- 

 lem of combatting locomotive smoke 

 ravages was recently effected by a rail- 

 road through the simple procedure of 

 coating an iron bridge with concrete. Al- 

 though the smoke darkened the white 

 concrete walls and certainly made them 

 unattractive in time, yet the iron was 

 perfectly protected and the structure in- 

 sured against deterioration. 



RADIUM AS A FERTILIZER 



Extensive tests of fertilizing fields with 

 radium by a university in this country, 

 although interesting from a scientific 

 point of view, will hardly appeal to the 

 average farmer. Experiments covering 

 a period of two years have been made 

 on patches of corn and soy beans with 

 the following results : 



Amounts of radium costing one dollar, 



ten dollars, and one hundred dollars per 

 acre have no detectable effect on the 

 crops. The amounts of radium emana- 

 tions used by Fabre, which were unsuc- 

 cessful in plots 4 inches square, would 

 cost on a commercial scale $58,800 per 

 acre. 



If radium affects plant growth at all, 

 the action must be that of a stimulant, 

 it is doubtful that radium forms a source 

 of energy, inasmuch as $1,000 worth of 

 the element acting for three and a half 

 months on one acre equals in total energy 

 the sun's rays on one square foot during 

 thirty seconds. 



A French inventor has secured very 

 promising results with .an automobile 

 driven by an aerial propeller. The propel- 

 ler is shaped like a bird's wings, which 

 is said to account for the vehicle's suc- 



cess. 



The Same Bridge as Above After it Was Covered Over with Concrete So as to Render it Impervious 



to the Action of Locomotive Smoke. 



