PRACTICAL 

 AGRICULTURAL CHEMISTRY 



SECTION I 



CHEMICAL MANIPULATION AND APPARATUS 



The student whose time is very limited, on wotking through the 

 experiments described in this book, may omit those paragraphs marked 

 with an asterisk. 



I. The Bunsen Burner. — Where gas can be obtained 

 the Bunsen burner (fig. i)will be found the most convenient 

 lamp for heating purposes. Before 

 use the coal-gas is mixed with air, and 

 when ignited burns with a feebly 

 luminous flame, which deposits no soot 

 when a solid object is held in the 

 flame. For this reason the Bunsen 

 or some other atmospheric burner is 

 nearly always employed for chemical 

 work in place of the luminous flame- 

 burner. The Bunsen burner (fig. i) 

 consists essentially of a gas-jet (#), 

 which is surrounded by an outer tube 

 (c), in which the air passing through 

 two inlets (b) mixes with the gas. 

 The mixture of air and gas is burnt at the top of the 

 outer tube (c). Over the air-holes fits a ring, which by 

 turning round will cut off either wholly or partially the supply 

 of air. When the flame is turned down it is necessary to re- 



B 



Fig. i 



