22 Estimations occurring in Agricultural Analysis [26 



platinum dish 2 inches in diameter by 1 inch in depth. Heat 

 it to redness over an Argand. Allow it to cool in a desiccator 

 and weigh it. Enter the result as shown below. Place the 

 dish on a clean white glazed tile, and transfer into it as much 

 as possible of the dried precipitate. Burn the filter paper in 

 a spiral of platinum wire exactly as directed in paragraph 20. 

 Shake the ash into the dish. With a small camel's-hair brush 

 sweep into the dish every particle which has drifted over on to 

 the tile. Place the dish with its contents over an Argand, and 

 ignite at a red heat for two or three minutes, or until any scrap 

 of charred filter which has escaped burning in the wire is com- 

 pletely reduced to ash. Allow to cool in a desiccator, and weigh. 

 26. Entry and Calculation. — The following example 

 shows the method of entry in the laboratory note book. The 

 weights are entered on the right-hand page, and the calcula- 

 tions made on the left : 



