INDEX 



215 



Q 



Quarantine, 23. 



Rainfall, 42-43, 64, 75-76. 



Rats, 30, 83. 



Recreation, 33-34, 89. 



Reflection of light, 175-178. 



Refraction of light, 177-178. 



Rents, 87-88. 



Respiration, 14-17. 



Revolution, of bodies, 173-175, 183- 



189. 



Roots, 105-106, 111-112, 139. 

 Rotation of bodies, 180-185. 

 Rubber, 159. 



Salt, 97-100. 

 Sand, 154-156. 

 Sanitation, 24-31, 122-123. 

 Satellites, 175, 197. 

 School attendance, 120-123. 

 Secretions, 6, 18. 

 Serum, 21-22. 

 Shadows, 172-175. 

 Sickness, 19-26, 29. 



prevention of, 19, 36. 

 Silos, 146. 

 Siphon, 57-58. 

 Skin, 3, 18. 

 Soap, 96-97, 137. 

 Soil air, 157. 

 Soil, cultivation of, 104, 143. 



nature of, 154-155. 

 Soil waters, 155-157. 

 Solar system, 195-197. 

 Solution, 44-48. 

 Spectrum, 177-179. 

 Standard time, 192. 

 Stars, 193-197. 

 Sterilization, 22. 

 Stimulants, 34-36. 



Streams, study of, 48-51. 

 Stress and strain, 39-40. 



Teeth, 5-6. 



Telegraph, key and sounder, 168-169. 



Temperature, 69-76. 



of body, 17-19. 

 Theory, 160. 

 Thermometers, 69-70. 

 Time-keeping, 189-192. 

 Toxins, 21-22. 



Transportation, 117-118, 144, 147. 

 Trees, for fruit, 106-107. 



planting of, 105-107, 147-148. 



pruning of, 107. 



spraying of, 149. 



studies of, 107-111. 

 Tuberculosis, 13-14. 

 Typhoid, 23. 



U 

 Universe, 196. 



V 



Valleys, 49-51. 

 Vapor, 10, 43, 90. 

 Vaporization, 4244. 



heat of, 43-44. 

 Ventilation, 12-14. 



W 



Wage earning, 119-121. 

 Water, 11, 41-44, 96. 

 Water supply, 27-29 

 Weather, 63-68, 73-76. 

 Weather forecasts, 64, 76. 

 Weather maps, 65-68. 

 Wells, 27-28. 

 Wheat, 150-151. 

 Wheelwork, 190-191. 

 Wind, 53, 60-62, 75-76. 

 Work, 162. 



Z 

 Zenith, 60. 



Printed in the United States of America. 



