SPIRIT OF NITROUS i;THER. ' I5I 



ethyl nitrite in the Hqnid. The temperature correction is one- 

 third of one per cent of the total percentage just found for 

 each degree, additive if temperature is beloAv, subtractive if 

 above. 25° C. {"j'j° F.). The barometric correction is four- 

 thirtieths of one per cent for each millimeter, additive if above, 

 subtractive if below, 760. 



When assayed according to the above method, Spirit of 

 Nitrous Ether should yield not less than 4 per cent of ethyl 

 nitrite." 



Schiiup Method. This determination, which is to be con- 

 ducted with a nitrometer, is outlined thus : "Open the stop- 

 cock of the measuring tube, raise the control-tube, and pour 

 into the latter a saturated solution of NaCl until the measuring 

 tube, including the bore of the stop-cock, is completely filled. 

 Then close the stop-cock and fix the control-tube at a lower 

 level. Now introduce into the funnel at the top of the measur- 

 ing tube a weighed cjuantity (about 4 gms.)* of spirit of nitrous 

 ether ; open the stop-cock, and allow the spirit to run into the 

 nitrometer, being careful that no air enters at the same time. 

 10 Cc. of potassium iodid T. S. are now added in the same 

 manner, and followed by 10 Cc. of normal sulphuric acid V. S. 

 Efifervescence takes place immediately, and after 30 to 60 min- 

 utes, when the volume of gas becomes constant, the control- 

 tube is lowered so as to make the level of the liquid in both 

 tubes the same, and the volume of the gas in the graduated' 

 tube read ofif. 



This volume, multiplied by 0.0030673 gm. gives the weight 

 of ethyl nitrite in the spirit taken for analysis. The product 

 multiplied by 100, and then divided by the weight of the spirit 

 taken, gives the per cent of pure ethyl nitrite present." 



Barometric and temperature corrections are to be made as 

 usual. 



A method similar to the latter was tried several years ago 

 by one of the authors upon the theory that it was more accurate 

 than the old and certainly easier of manipulation than the new 

 U. S. P. method. 



* It is convenient to take 5 Cc. accurately measured, and calculate its 

 weight by multiplying by the specific gravity. 



