314 EXPERIMENT STATION EECORD. [Vol.43 



Tlie experimental data obtained on the different flours showed a wide rnng:e 

 in offal content, not only in the different grades but also among flours of the 

 same commercial grade. The examination of mill stocks showed the offal 

 content of the break-roll products to be high and that of middlings to be 

 lower and to decrease the more thorough the purification process. Tho com- 

 mercial grades of patent flours examined, ranging from 35 to 90 per cent ex- 

 traction, gave an average total offal count of 57, straight flours of from 90 to 

 100 per cent an average offal count of 111, clear flours of from 5.5 to 52 per 

 cent extraction an oftal count of 273, and low-grade flours of from 2 to 10 per 

 cent an offal count of 433. 



The best grades of flour of the experimental series gave a slightly lower 

 offal count than the corresponding grade of the commercial series, the two 

 intermediate grades a lower offal count, and the lower grade flours about the 

 same oft'al count as the corresponding connuercial floui's. 



The inferences drawn from this study are that there is little uniformity in 

 the matter of grading finished flours in different mills and that all mills do 

 not composite finished flours in the same manner. 



A bibliography of 22 titles is appended. 



Invertin in pure honey, A. Caillas {Compt. Rend. Acad. Sci. [Pmis], 170 

 (10:20), No. 10, pp. 589-592). — Invertin to the extent of 0.049 per cent was iso- 

 lated from a sample of pure honey. Its presence is thought to explain why 

 two analyses of honey made at widely separated intervals of time do not give, 

 the same results as to their content in sugar, the amount of sucrose sometimes 

 decreasing from 8 per cent in fresh honey to from 2 to 3 per cent after some 

 years. It is thought that the invertin enclosed in the honey continues its 

 action until equilibrium is established and the products of the reaction arrest 

 the action of the diastase. 



Determination of invert sugar with the help of potassium thiocyanate 

 and potassium lodid, G. Bruhns (Centhl. ZucJcerindus., 27 {1919), Nos. 37, pp. 

 621, 622; 38, pp. 6Jf2, 643; 39, pp. 664-666; 44, pp. 767-771).— The author de- 

 scribes and discusses the details of a method for determining invert sugar which 

 is said to be rapid, economical, and productive of as accurate results as the 

 well-known metliods heretofore used. Tlie technique is as follows: 



Ten CO. of a copper solution containing 69.28 gui. of finely crystallized CuSO* 

 per liter and 10 cc. of alkaline tartrate solution containing 346 gm. of Rochelle 

 salts and 100 gm. of NaOH per liter are mixed in an Erlenmeyer flask with 

 20 cc. of the sugar solution, which should contain not more than 4 gm. of 

 sucrose. The mixture is kept at boiling temperature for two minutes by care- 

 ful heating on a wire gauze, after which 50 cc. of wat^r at room temperature 

 is added, the mouth of the flask is covered with a small beaker, and the flask 

 cooled in a stream of water. 



To the cooled solution is then added 5 cc. of a solution containing 0.67 gm. 

 of KCNS- and 0.1 gm. of KI, the mixture is shaken, 10 cc. of 6 n/HC1 or 6.5/n 

 H2SO4 is added, and thiosulphate solution (34.4 gm. thiosulphate and 0.1 NaOH 

 per liter) is run in rapidly from a burette until the original brown color on 

 shaking temporarily turns gray. A little starch solution is then added, and 

 the titration continued until tlie precipitate becomes light yellow and does not 

 turn blue or gray on standing for five minutes. The amount ?)f thiosulphate 

 solution used is subtracted from the iodin titer of an equal amount of the 

 same sugar solution determined without heating, and from this result the 

 amount of invert sugar is calculated from a table of standard values. 



Some vanillin oxidation products: Methods of analysis which exclude 

 tliom, W. G. BowEKS and J. Moyek {North Dakota Sta. Spec. Bui.. 5 {1920), No. 

 16, pp. 518-520). — The authors discuss the behavior of vanillin with some of the 



