[ 8,5 ] 



done a third time before the filtrate comes out clear. This 

 is transferred and carefully washed out into a small weighed 

 beaker, left on the steamer to dry, the beaker being gradually 

 filled up while on the steamer, and when apparently dry, it is 

 left inside the water-oven, to get completely dry. Next 

 day, it is cooled in the desiccator, and weighed. The increase 

 in weight is due to the soluble matter in 10 grams of the 

 soil. 



(4) Nitrogen. 5 grams of the soil should be weighed 

 out in a watch-glass and subjected to combustion for over 

 2 hours mixed up with dry soda-lime in the following 

 manner: A tube about 14" long, drawn out to a fine point 

 at one end and closed, and open at the other end should be 

 taken. This is filled with hot soda lime. It is emptied on a 

 clean porcelain bason, all but i". A funnel with a short stem 

 is held, with the lower end stopped by means of the index 

 finger of the left hand, while a portion of the soda-lime is 

 poured on to it. Then the 5 grams of soil should be put on 

 it. A little more of the soda-lime should be used to clean 

 the watch-glass of any adhering particles, and this also trans- 

 ferred on to the funnel. The soil and the top part of the 

 soda-lime are then mixed up with a spatula, the finger is slipt 

 out, and the stem inserted into the combustion tube, and the 

 mixture transferred into the tube. The remaining third of the 

 soda-lime still on the bason, is poured down through the 

 funnel to effect complete transference of all adhering particles 

 of soil into the tube. About J" f asbestos plug should be 

 then inserted, then the H 2 SO 4 -bulb containing 20 c. c. (i 

 pipette-ful) of H 2 SO 4 is fitted on with a cork. The whole 

 apparatus is then placed on a furnace, with the cork and the 

 H 2 SO 4 -bulb fairly out of contact with the furnace. With the 

 help of a spirit-lamp it is ascertained whether the apparatus is 

 air-tight. The combustion is commenced from the near end 

 of the tube, the last burner near the narrow end of the tube 

 being lighted after 2 hours. With cold water the narrow end is 



