Davy — Neio Method for the Determination of Nitrites. 567 



Dr. Tichborne, "who procured it direct from Berlin. On tlie other 

 hand, the reagent used in my test may be got for a few pence at 

 any druggist's shop : again, Griess's test solution will not keep, as 

 it quickly acquires the same colouration that is produced by the reac- 

 tion of nitrous acid or a nitrite on it, even when it is kept in closely- 

 stoppered bottles; and therefore requires to be freshly made and 

 titrated almost every time it is employed ; whereas the gallic acid solu- 

 tion which I have recommended will, I find, keep for a very consi- 

 derable time without apparently undergoing any alteration requiring 

 its fresh titration, Avhich is an important advantage. In conclusion, I 

 may add, that whatever may be the comparative merits of the two 

 tests contrasted, I have but little doubt that the one I have proposed 

 will be found to be a useful and expeditious method for both the qua- 

 litative and quantitative determination of the nitrites under different 

 circumstances. 



