TEMPERATURE. 



375 



was first observed by Lamarck, in 1777, but without 

 any precise determination of the heat experienced. 

 In 1800, Sennebrier measured with a thermometer 

 the heat evolved in the 

 common arum, and 

 found it 8 - 6' cent. In 

 the early part of the 

 same century Hubert 

 states that a thermo- 

 meter placed in the 

 centre of five spadices of 

 A rum cordifolium, in the 

 Isle of France, stood at 

 1 3 1° Fahr., and in twelve 

 at 1424° Fahr., while the 

 temperature of the air 

 was only 74-75 . This 

 showed an elevation of 

 56° and 68 . 1 Schultz 

 observed the flowers of 

 Caladium pinnatifolium, 

 at Berlin, in 1828, and 

 M. Treviranus published 

 the results of investigations on several species of 

 Arum, in 1829. Gcepperd, in 1832, found the tem- 

 perature of the spadix of Arum dracunculus rose to 



Fig. 83. 



—Wake-robin {Arum 

 maculatum). 



Hubert; in " Bory de St. Vincent Voyage," ii., p. 68. 



