199 



of reagent for 25 grams of sugar or sirup, a proportion of 1 cc per gram of substance. The 

 maximum precipitate was in this case produced by 1 cc to 5 grams of substance. A 

 lead number determination was accordingly made on the 10 per cent maple sirup in 

 question with a lead subacetate solution five times weaker than that prescribed by 

 \Viutoii, and the figure 0.137 obtained. This solution is much too weak to be used 

 with pure maple sirups, as it contains only about 0.8 gram of lead (figured as metal) 

 per KM) cc, whereas 100 grams of an average maple sugar will precipitate in Winton's 

 in. -i hod over 2 grams of lead. To show that a large excess of lead reagent is necessary 

 to produce a normal precipitate, a sirup containing 30 per cent of cane sugar and 30 

 per cent of maple sugar was prepared and the lead number determined, using both the 

 \Vinton solution and the one diluted five times. With the weak subacetate a lead 

 number of 0.29 was obtained, with the strong, 0.72. In the former case there was just 

 enough basic -uku-etate in the 25 cc of solution added to have precipitated all of the 

 lead if a normal precipitation had occurred, and no lead would have appeared in the 

 filtrate. Actually the amount of lead was insufficient for maximum precipitation and 

 the l.-a.l number was accordingly too low. On comparing the amount of lead remain- 

 ing in solution with that added it was seen that the former was 62 per cent of the latter. 

 I'.y the regular meth(xl the excess of lead producing a normal lead number was found 

 to be 81.7 per cent. In the case of the 10 per cent maple sirup in which no precipita- 

 tion was produced by the regular solution and in which a lead number of 0.137 was 

 obtained with the I in ."> dilution, it was found that the excess of lead was 82.1 per cent. 

 AB a conclusion it would appear that at least 62 per cent excess of lead is necessary 

 for a complete precipitation, an excess of lead much greater than 80 per cent tends to 

 prevent precipitation, and that a zero lead number obtained by the regular method 

 doe* not indicate that so-oalled cane and maple sirups contain no maple sugar. 



It ha _:>-ste<l that the lead number of the mixture containing 10 per cent of 



maple -uu'ar mL'lit '-,'i ve normal results if the solution after addition of the lead reagent 

 allowed to stand longer than two hours, as was done in the previous determina- 

 tion- i >n standing for twenty-four hours the opalescence which formed on adding 

 the l-ad suhacetate had collected into a very slight precipitate, which was matched 

 in the blank by one of similar proportions, though boiled distilled water had been used 

 in all C*0ea, After filtering in the usual way and determining the lead number zero 

 values were obtained as before. 



THE DETERMINATION OF FUSEL OIL BY ALKALINE 

 PERMANGANATE. 



By A. S. MITCHELL and C. R. SMITH. 



I oil Ci .Heists chiefly of a mixture of normal and isopropyl, normal and isobutyl, 

 active amyl and isoamyl, and hexyl alcohols. The Allen-Marquardt method is in 

 reality an "estimation in terms of amyl alcohol of the higher alcohols which are dis- 

 >olv-<"l and retained by carbon tetrachlorid, under fixed conditions, and converted 

 into volatile acids by oxidation with a chromic acid mixture. 



This paper is the result of an effort to learn the conditions necessary to produce 

 definite oxidation of the various alcohols by alkaline potassium permanganate solu- 

 tion. 1 1 was hoped to avoid prolonged digestion with the oxidizing agent and, later, 

 t he subsequent distillation with the attendant concentration of the oxidizing mixture, 

 ordinary amyl alcohol, which consists of iso and active amyl alcohols, was first 

 experimented upon. In the first effort the manganese dioxid and unreduced per- 

 manganate was not removed after acidifying for the distillation of the free acids. 

 The mixture bumped so badly that the distillation could not be completed. It 

 became necessary to remove the manganese dioxid and permanganic acid. Oxalu 

 a.i.l vai t m,l and rejected. Hydrogen peroxid was finally selected for this purpose. 



