and the mixture brought again to boiling heat, and at this 

 stage 50 c. c. of a 5% KHO-solution are added. The 

 mixture should be boiled exactly for half an hour again. It 

 is again filtered through linen rag, washed, and transferred 

 to a weighed crucible. The crucible is left on the steam-bath 

 over-night and in the morning transferred to the water-oven. 

 When perfectly dry it is weighed, the increase of weight 

 being due to the insoluble fibrous matter contained in 3 grams. 

 From this is subtracted, the weight of the ash which is deter- 

 mined by igniting the fibrous matter in the crucible, cooling 

 it in the desiccator and weighing it again. 



(4) Oil. Two grams of the finely powdered cake are 

 folded up in a piece of Swedish filter-paper, and inserted in 

 a tube between plugs of carded cotton wool ; above the upper 

 cotton plug is placed a loosely coiled brass spiral. A glass 

 flask is weighed, and a quantity of Ether introduced into it, 

 and the tube with the cake inside it is fitted on to this flask 

 with the help of a perforated cork, while the upper end of 

 the tube is connected by means of a bent-tube with a flask 

 .which remains plunged in cool water throughout the opera- 

 tion ; hot water and coJd water being alternately applied 

 under the flask with the ether. When hot water is applied, 

 the ether evaporates, passes through the cake, and becomes 

 condensed in the other flask. When cold water is next ap- 

 plied, the ether returns bringing some oil in extraction. The 

 etherification process is repeated 10 times, when the ether 

 returning through the end of the tube over the ether-flask is 

 found quite free from any trace of oil. The flask is then 

 dried on the steamer, and then put inside the water- 

 oven, and weighed. The increase of weight is due to 

 oil. 



1,419. Estimation of Nitrogen. This is done exactly in 

 the same way as in the case of the sample of soil and of 

 bone-meal, the analysis of which has been already described 

 in detail. 



