Chapter 4 



The Importance of "Impurities" and Trace Substances 



The first question generally asked of a practicing professional 

 chemist is "What will it cost to analyze this sample?" The sample 

 may be anything from a patent medicine to a bit of composition 

 or plastic. The first question the chemist should ask is, "To 

 what use do you expect to put this analysis?" As a rule, the 

 answer will be, "I want to make the same thing." The chemist 

 must then explain that while a routine analysis may be one step 

 toward this objective, it seldom gives the answer; for a final 

 product rarely reveals directly the original raw materials which 

 were used to make it, or the details of the process. Thus, an 

 analysis of a loaf of bread, showing fat, carbohydrate, protein and 

 salt, would hardly tell anyone how to produce a loaf just like it. 

 Part of the original carbohydrate has been fermented away by the 

 yeast, which, in turn, has added somewhat to the protein; and in 

 baking, much of the water used to make the dough and practically 

 all the alcohol formed by the yeast have been driven off. A large 

 Swedish bakery runs most of its delivery automobiles with alcohol 

 condensed from its ovens; and I have heard of a small baker who 

 used to go on an occasional spree with the alcoholic liquid he 

 condensed from oven vapors, on the underside of a large metal 

 sheet cooled by spring water. 



Consider an actual case. A client, with an air of great mystery, 

 presented a chemist with a sample of a red paste and asked the 

 cost of an analysis — "that's all." The client admitted that he 

 expected the analysis would show him how to make the product, 

 and on being told that this was most improbable, expressed sur- 

 prise. At first he refused to say what the material was, where it 

 came from, or for what purpose it was intended; and he was told 

 to find a chemist he could trust. Thereupon, he decided to take 

 the chemist into his confidence, and revealed that he was using 

 the red paste in a special cosmetic, and that it cost him five dollars 

 a pound. This high price made it impossible for him to operate 



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