ANALYTICAL EDITION
54 VALUE TABLE v. DIASTASE OF
HONBY ACIDITY
OF
Clover
DIAETAEB VALUB AB SHOWN BY REIODINB TEST ACTIOS SOLUTIONADDED T U B E @ METHOD STARCH"1 drop 2 drops pH range
Buckwheat
0 , 2 1 2 Lothrop-Paine Pauly Gothe
Tulip-poplar
0 , 1 8 3 Pauly
Gothe Alfalfa
HONEYAS AFFECTEDBY KIND values, as well as the interpretation of the end point of the
SOLUBLESTARCH USED
(Calcd; as formic) % 0.'185 Lothrop-Paine Pauly Gothe
FLORAL EOERCE
0 . 1 2 2 Pauly
4 2 1 Range 1 1 1 Range 2 8 1 Range 2 8
i 5 1
Clover
Gothe 5
39 29 23.8 23-39 23 23 14 14-23 29 14 18 14-29 39 23
39
.. ..
5.32-5.81 5.28-5.29 5.89-4.71
23 29
5.29-5.31 5.25-5.27 5.38-4.76
23-29 29 18
18-29 50 23
39 39
29 28
23 a w e 23-39 50 2 29 S 39 1 Range 29-50
0 . 1 8 8 Pauly
Vol. 5, No. 1
23-50 50+ 29 29-50+
5.32-5.32 5.26-5.25 6.61-4.75 5.31-5.33 5.26-5.29 5.24-5.26 5.24-5.26 5.42-4.58 5.28-5.30 5.33-5.25 5.76-4.49
Numbers in this column refer t o starch solutions recorded in Table I.
The data obtained in the application of the above-described mode of procedure for the determination of the diastase values of honey are shown in Table V. The influence exerted by the quality of the soluble starch, upon the observed diastase
reaction when expressed in terms of quantity of iodine test solution used, are so obvious as hardly to require comment. However, in analyzing the data statistically, it appears that a minimum variation of 64 per cent and a maximum of 100 were found in the diastase value of the honeys under examination. Quantitatively these figures have littIe significance because the survey is probably insufficient with respect to number of honeys to which the modiiied technic has been applied. Qualitatively, however, they show that the character of the soluble starch which serves as substrate is a factor which may easily nullify the results of a determination of the diastatic activity of a honey which has otherwise been carried out with meticulous attention to detail. A standard starch is obviously necessary for this work.
LITERATURE CITED (1) Fiehe, J., and Kordatzki, W., 2. Untersuch. Lebensm., 55, 163-9 (1928). (2) Gothe, F., 2.Nahr. Genussm., 28,286-321 (1914). (3) Lintner, C.J., J. prakt. Chem., 142,378-94 (1886). (4)Lothrop, R. E., and Paine, H. S., IND.ENQ.CHZM.,23, 71-4 (1931). ( 5 ) Small, J. C., J . Am. Chem. Soc., 41,114-20 (1919). RBCBIVBDAugust 20, 1932. Presented before the joint session of the Divisions of Agrioultural and Food Chemistry and Biological Chemistry at the 84th Meeting of the American Chemical Society, Denver, Colo., August 22 to 26, 1932.
A Device for the Calibration of the Variable-Deviation Spectroscope CLARENCE F. GRAHAM, 493 Western Ave., Albany, N. Y.
1
THE calibration of the variable-deviation spectroscope can be simplified by the device shown in the accompanying illustrations, which applies to the spectroscope the registration system of the mirror galvanometer and allows the
j'* FIGURE 1
telescope deviations to be read off on a long illuminated scale in place of the arc of a graduated circle. Figure 1shows a bar clamped to the telescope of a spectroscope, with its end brought forward over the prism. A mirror about 2 ern. square is mounted perpendicular to the bar in such a position that the axis of rotation of the telescope lies in the plane of the mirror. A projector casts upon the mirror the vertical image of a hair, which is reflected to a scale a t a convenient distance from the spectroscope. The
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II
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\
\ \
\ \ \ /
/
FIGURE2
projector, spectroscope, and scale are fastened rigidly in relation to one another, as shown in Figure 2, and calibration is carried out on the scale in the usual way. The deviation readings of the telescope can be spread out on the scale to any desired extent by increasing the distance between mirror and scale, and a t the same time the compression of the red end of the spectrum can be counteracted by arranging the parts of the system so that the beam from the mirror strikes the scale at right angles when the telescope is a t the extreme violet end of the spectrum. With a flat scale, the readings will vary as the tangent of twice the angle of telescope deviation, and will widen out rapidly as the beam strikes the scale more obliquely. The projector can easily be made from a 6-volt tail-light FIGURE3 bulb, the condensing lens of a flashlight, and a small reading lens. A 6- to &volt bell-ringing transformer will supply sufficient current to operate the bulb at full capacity. The image of the hair on a bright circle of light is produced by a hair stretched across an 8-mm. round hole in a small piece of sheet brass, and cemented a t its ends to the brass. The lighted circle surrounding the image of the hair allows the adjacent numbers on the scale to be read, as shown in Figure 3. The expense of the whole device is nominal, and it has proved a great convenience in quickly picking up desired lines in the spectroscope. REOBXVBDSeptember 29, 1932.
