THE PI7BITY OF GLYCERIN. 31 



J. C. LARKIN Co. 



In looking back over our tests we find one made on the batch of glycerin from which 

 the sample forwarded you was taken. We find that this test indicates the glycerin 

 to be very much better quality than your tests show. Of course, the matter of odor, 

 darkness of color when mixed with sulphuric acid, etc., is largely a matter of judg- 

 ment, and the tests are not specific enough to enable two independent operators to 

 check exactly their results. For instance, what you might consider a strong odor, or 

 a dark color, might not be so considered by our chemist, etc. 



We note, however, that you state that this glycerin reduces ammoniacal silver 

 nitrate when tested by the U. S. P. method. We never turned out a glycerin, as far 

 as we are aware, that responded to this test. We are making tests of our glycerin 

 continually as we produce it, and looking back over our files we can not find a single 

 test which shows a quality as poor as your tests would indicate. We would call your 

 attention to the fact that, as far as we can learn, the sample of the glycerin which you 

 have tested is almost two years old. We can not tell what happened to it during the 

 interval after it left our hands and was tested by you. 



PEET BROS. MANUFACTURING Co. 



It is barely possible that our C. P. glycerin contains a trace of sodium chlorid, but 

 it is almost inconceivable that it should contain a trace of sulphate, as we uae muriatic 

 acid exclusively in its preparation, with the resultant conversion of any sulphate 

 which might be present into chlorids. 



Also notice you mention a slight trace of arsenic. We would like to ask what test 

 was used in aniving at this conclusion? 



POWERS, WEIGHTMAN, ROSENGARTEN Co. 



Referring to your favor of the 10th instant, regarding the report of examination by 

 the Department of Agriculture on our sample of glycerin, we would advise that some 

 of our tests agree with those made by the department, but vary in others as follows: 



Test 3: D. A. Strong aromatic odor on heating at temperature of water bath. 

 P. W. R. Slight odor of volatile fat acids on heating at water bath temperature. 



Teat 4: D. A. Unpleasant ethereal odor on warming with alcohol and sulphuric 

 acid. P. W. R. Pleasant ethereal odor on wanning with alcohol and sulphuric acid. 



Test 5: D. A. Dark yellow color with strong odor when mixed with equal volume 

 of sulphuric acid in the cold. P. W. R. Dark yellow color and mild odor when 

 mixed with equal volume of sulphuric acid without heating (the mixture becomes 

 hot when mixed). Pale yellow and faint odor when mixture is kept cold with water. 



Test 6: D. A. Reduces ammoniacal silver nitrate U. S. P. test. P. W. R. This 

 test is doubtful. No reaction reported in two tests out of three. 



Test 7: D. A. Slight color with ammoniacal silver nitrate, Hager's directions. 

 P. W. R. No reaction. Hager's directions rather vague; there may be a reaction 

 under some conditions of applying the test. 



Test 10: D. A. Reduces Fehling's solution in the cold on standing, no reduction 

 on heating. P. W. R. No reduction, either hot or cold. 



Test 11: D. A. Reduces Fehling's solution made according to Haine; sugar none. 

 P. W. R. Does not reduce Fehling's solution made according to Haine. 



Of course the same sample was not used in both instances, which doubtless accounts 

 for some of the differences shown above. However, both tests seem to agree that the 

 glycerin contains the merest trace of a fat acid, which most likely is butyric. 



PRICE'S PATENT CANDLE Co. (LTD.). 



We may say at once that the results differ so widely from those obtained from the 

 examination of our current make, all of which is carefully tested before issue, that 

 we are quite at a loss to understand the divergence. 



