26 JOURNAL OF THE 



usin^ ten tons of coal for heating purposes during the 

 winter could get along very nicely with one ton if the 

 heating arrangements were perfected. Any one who 

 has watched, on a still day, the long lines of smoke left 

 by passing trains or the black trails stretching for 

 miles behind ocean steamers can realize our prodigal 

 waste of nature's generous gift. Still I do not think 

 there is much reason for the dread that we are hastening 

 to a time when the coal question will lead to a new 

 struggle for existence, a painful illustration of the 

 principle styled "the survival of the fittest." Many 

 estimates of the coal supply and its probable rate of 

 exhaustion have been given. These are based on very 

 imperfect data and vary greatly but they all agree in 

 giving us a respite of from one to two centuries. Tak- 

 ing these estimates as approximately correct and agree- 

 ing to the assumption that the use will increase at the 

 rapid rate of the past quarter of a century, does not a 

 greater danger threaten than the comparatively slight 

 one of being forced to eat our food raw and winter in 

 the tropics? 



Geologists tell us that these coal deposits were laid 

 away at a time when the proportion of carbon dioxide 

 in the air was much greater than it is now. These 

 masses of coal represent carbon dioxide decomposed and 

 so made available by plant life and then stored away. 

 We dig it up and burn it back to the original form, re- 

 storing the carbon dioxide to the air. These processes 

 of decomposition and reoxidation go on side by side at 

 present and Saussure has supposed a sort of equilib- 

 rium between the forces removing the carbon dioxide 

 from the atmosphere, such as the growth of plants, the 

 washing of rain etc., and those restoring it, as the 

 breathing- of animals, combustion of organic matter 



