ISOTHERMAL LINfiS. 127 



The growing zone in the United States for the remontant 

 type of carnations lies between 37 degrees and 43 degrees north 

 latitude. The isotherm indicated on the map has a mean an- 

 nual temperature of 50 degrees. It is the equator of the empire 

 of Dianthus Semperflorens, the meridian of its home and health, 

 its profits and prophecies. It is the only belt of land on earth in 

 which Alegatiere's cross-fertilized product has developed into a 

 carnation that will unfold its petals to an Arctic sun and fling its 

 perfume on the winds of winter. Latitudes and longitudes are 

 imaginary lines on the earth's surface for geographical convenience. 

 Isotherms are lines drawn around the world by the finger of the 

 Almighty along which plants and animals hug congenial condi- 

 tions. These lines are as stable as the earth's axis and enduring as 

 their Fauna and Flora. It must not be understood that carna- 

 tions will not grow north or south of the 5o-degree isotherm, but 

 if they do, they must modify that specific type of character which 

 gives them esteemed value in that isotherm. Some forms of veg- 

 etation reach their greatest perfection when far removed from the 

 latitude of their nativity. The potato has an insignificant bulblet 

 in its native home, but feeds millions on its monstrous tubers in a 

 different latitude. There is a typical isotherm on which every 

 species of vegetation will reach its highest evolvement for the 

 gratification of man. 



The 50- degree isotherm has been established by the Agricul- 

 tural Department of the United States government as far west as 

 the loo-degree of west longitude, by twenty years of accurate ex- 

 periments; west of that the department informs us the line is not 

 so well established, but is thought to bend rapidly to the north. 

 The line strikes the continent on the Atlantic seaboard near Bos- 

 ton, runs irregularly on the north of the 40 degrees north latitude 

 as far west as Denver and then from mountain ranges and gulf 

 stream inclines suddenly toward the north, striking the Pacific 

 Ocean near Vancouver Islands. 



The average altitude of the land on this isotherm above sea 

 level is 1000 feet. It has an annual average rainfall of 40 inches, 



