SPIRIT OF NITROUS ETHER. 



^55 



bonate does not make aii}^ appreciable difference is shown in 

 Table 27 which gives the results on the same samples, using 

 the modified method, both with and without the reagent in 

 question. It will be noted that in two cases slightly higher 

 results were obtained when using the bicarbonate while in two 

 other cases the reverse was true. These differences, however, 

 are so small that they might occur when the determinations 

 were made as nearly alike as it is possible to duplicate, and 

 indicate no advantage obtained by the use of potassium bicar- 

 bonate. In these cases the shaking out was done directly in 

 the sample bottle after the first determination had been made. 



Table 27. 



Analysis of Szveet Spirit of Nitre With and Without the Use of 



Potassium Bicarbonate. 



Number. 



Ethtl Nitrite Found. Per Cent. 



Modified Method. 



Modified Method 

 Using KHC03 



10 ,495 



3.48 



3.40 



10,510 



2.6S 



2.70 



10 ,563 



2.96 



3.03 



10 ,579 



4.46 



4.44 



The sentence quoted below from the Pharmacopoeia of 1900, 

 and which appears also in the Schimpf Method, "wlien the vol- 

 ume of gas has become constant (within thirty to sixty minutes) 

 note the volume of gas collected" would lead one unfamiliar 

 with this reaction to suppose that the volume of gas did become 

 constant within an hour. As a matter of fact it very seldom 

 or never does. Experiments were made to determine, if possi- 

 ble, when the volume of gas did finally become con- 

 stant and also to determine, if possible, a factor 

 which might be applied to correct for the volume of gas 

 generated after the one hour period. Determinations were 

 allowed to run for various periods up to three days and 

 at the end of this 72 hours the volume of gas was still increas- 

 ing very slowly. In Table 28 the results of these observations 

 are given. In the second column is given the corrected reading 

 taken after the hour period had elapsed and upon which was 



