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PART III 



THE ESTIMATION OF NITROGEN 



The percentage of nitrogen affects the value of both feeding 

 materials and manures to a greater extent than that of any 

 other element The determination of nitrogen is conse- 

 quently an operation of the greatest importance in agricultural 

 work. It has therefore been thought well to devote a chapter 

 entirely to describing the best methods at present in use for 

 making this estimation. 



85. Permanent Apparatus. — In all agricultural labora- 

 tories apparatus is kept permanently set up for the determina- 

 tion of nitrogen. It should be remembered, therefore, that 

 although some processes — Kjeldahl's, for instance — may seem 

 very long and tedious when only one estimation is required, 

 they become comparatively simple when the apparatus is once 

 set up and used frequently. 



Fig. 25 is taken from a photograph of the bench used for 

 nitrogen determination in the laboratory of the Notts County 

 Council. The two bottles a and b contain respectively standard 

 acid and alkali which may be run into the burettes beneath. 

 The bottle c contains strong caustic soda, and is in connection 

 with an arrangement for measuring out 100 c.c. at a time. On 

 the lower shelf are bottles containing the various substances 

 used in the different processes, and on the bench are different 

 pieces of apparatus which are dealt with in detail in the 

 descriptions of those processes for which they are used. 



