To determine the nitrogen content in a solid sample (1-5 g), the material is finely ground in a hot mortar with soda lime (CaO/NaOH 3:1) and used to fill  a 50 cm long, 2 cm wide crystal, quartz, porcelain or iron tube B almost to the brim. The tube is held by a metal shell A, and when slowly heated with an alcohol burner C, the nitrogen is converted to gaseous ammonia, which can be collected and absorbed for further analysis. The whole process lasts about 40'.
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Alessandri, P. E. Analisi Volumetrica Applicata Ai Prodotti Commerciali e Industriali; Ulrico Hoepli: Milano, 1895.