T H E J O C’ R AT8L 0 F I S D L7ST RI .LI A
June, 1914
Ne E S G I &VE E RI
T A\
G C H E X I S T R I.’
517
NOTES AND CORRESPONDENCE FORMULA FOR CONTENTS OF CYLINDRICAL TANKS W I T H SPHERICAL ENDS Editor of the Journal of Industrial and Engineering Chemistry: I n most all chemical plants of any size many cylindrical tanks with spherical ends are used for liquids. T o ascertain contents of these tanks by measuring the depth of the liquid inside, it is necessary to consult a curve representing the gallons per inch of depth. It is a comparatively simple matter to calculate the volume per inch of the main portion of the tank, but calculating t h a t of the spherical ends is a more complicated problem.
2
NOTE ON INFLUENCE OF RATE OF STIRRING ON TITRE DETERMINATIONS IN FATS Editor of the Journal of Industrial and Engineering Chemistry: At the time that the official method now in use in determining the Titre of Fats was adopted, i t was noted t h a t the stirring method, i. e . , continuous stirring of the fatty acids until the temperature was stationary for 30 seconds, gave tests higher than if the fatty acid was cooled t o the stopping point without stirring; this higher test ranged from over I ’ C. in case of oils such as Cottonseed t o only 0 .I ’ or less in the case of Stearine. Since this stirring method was adopted, the custom in this laboratory has been t o stir the fatty acids by means of a stirrer run by a water-motor and i t was soon noticed that the number of revolutions per minute of the fatty acids (the acids being revolved and the thermometer kept stationary) had a decided influence on the test. I give below a number of figures made in two different fats, the first being a Garbage Grease (Naphtha extracted) and the second a tallow: Garbage Grease
Tallow
0
TANK END The DuPont Fabrikoid Co., manufacturers of artificial leathers, use about ten of these cylindrical tanks with spherical ends. They are mostly of different sizes and I was given the task of plotting the necessary curves. I have worked out the following formula : 8-h’ v’~ m 2 -z? %, m z - x? --z? ~~~~~
‘
dz dx d y ’\-h
\a
\b
The limits are obtained from the equation of the sphere, c2 b2. x2 y2 z? = m2,where m = -
+
+ +
2b
By integration and expansion, V where, A =
x
a3 mz-am------ac
B
c = - -a- - -
3 a6 4om3
6m
2
a r r = - ___ 6m 6
a3
-~
-
36m3 a3
1
=
3 as
80m5 9
f15
+
-h1
--h
’
5
6c
+-
a
40m3 80mj 32om’ 40c3 Substituting the value of m 2 for z in the formula, we obtain t h e volume in both ends of half the tank, VI,, By substituting h, the depth as measured for z in the formula and subtracting this volume, Vz, from VI/,, we get the volume in the ends for the desired depth of liquid, V = - Vz, or the formula becomes.
V
=
[AT
+ B T + C S ] - [Ah + Bh3 + C h j ]
L. E. CARPENTER 110 GRANDSTREET, hTEWBL‘RGH, hTEwYORK February 17, 1914
Revolutions per min 60 80 1 80 220
Stopping point 36.35 36.50
60 60 180 220
43.60 4 2 , 70 44.60 44.60
3i.20
37.40
Final highcst point 37.05 37.20 37.55 3 7 65
45.00
It will be noticed that when the speed is only 60 revolutions the first stopping point is much lower than when it is 180 or 2 2 0 , in fact, the less the speed the lower the first stopping point and as the speed is increased, the stopping point rises with each increase. I n the case of the tallow, the rate above 180 makes no difference with either temperature but with the grease a difference of 0.1’ is noted. A quite remarkable difference in the first stopping point is noted in the tallow a t 60 revolutions, although the final temperature is practically the same In my opinion, a large number of the differences between chemists on this test is due to this point. At the present time the directions state only that the acids “shall be stirred slowly,” which might mean anything. I believe that a definite rate of stirring should be specified and my judgment is that 180 revolutions should be taken as the standard, as a higher rate is rather impracticable and a lower certainly does not give correct figures. As the titre point is the highest temperature recorded by the heat of crystallization of the fatty acids, any method that will give this highest heat should be the correct one, as it is obvious that the only source of heat is from the crystallizing. In fact, a higher rate of stirring would, if anything, tend to cool the acids and so give a low test. A . G. STILLWELL i 6 1 2 PIXESr.. ~ - E WYORK M a r c h 30. 1911
A SHAKER FOR T H E MECHANICAL ANALYSIS OF SOILS Editor of the Journal of Industrial and Engiizeering Chemistry: In an article in February, 1914, THIS JOURNAL,entitled “ A Shaker for the Mechanical Analysis of Soil,” by Freeman Ward, the author makes a comparison between the shaking machine devised by him and the one used by the Bureau of Soils. He states: “The writer believes t h a t ’ h i s method is better than the one used by the Bureau of Soils in two respects. I n the first place, the machine is simple and inexpensive. A greater advantage is the saving of time. Clean separations can be effected in three hours, and in some cases two hours; this is a saving of a t least four hours over the Bureau method. If the quantity of the water used in the bottles is reduced one-half, a clean separation results in much less than three hours, but there is a tendency for the grains t o suffer some abrasion.”
5 18
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
Vol. 6 . No. 6
I
The machine is undoubtedly simple and inexpensive. Attention must be called t o the fact, however, t h a t the Ward apparatus carries only 16 bottles while the Bureau of Soils apparatus carries 48, giving the latter three times the capacity. The Ward shaker must be run a t a certain definite speed t o be efficient. If the speed is too high, there is a centrifugal effect resulting, and if too slow, the action is merely pouring. The Bureau of Soils machine is even more efficient a t high speeds than at moderate speeds. As to the second conclusion, t h a t a saving of time results, the author has taken the statement in Bureau of Soils Bulletin No. 84 t h a t the samples of soil are “shaken by the mechanical shaking machine for a t least seven hours,” t o mean that seven hours are essential. As a matter of fact, this time is taken because in some rare instances as long a time as this has been found necessary. A majority of soils, especially sandy soils, do not need seven hours. The length of time of shaking does not result in any loss of time t o the operator, as the analyst merely keeps 48 soils shaking on the machine all therime and cannot complete the analyses rapidly enough with a force of three men t o keep the machine cleared of samples ready for analysis. If more samples should be required, all that is necessary is to run the machine during the night, and thus the capacity of the machine would be doubled. In the light of these facts, i t seems to the writer that Mr. TVard’s statement t h a t his “method is better than the one used by the Bureau of Soils” is miqleading. A more accurate claim would be t h a t his machine is satisfactory where such a small amount of work is done as to preclude buying an expensive piece of apparatus. His machine can be cheaply constructed and 15 greatly superior t o pestling. C. C. FLETCHER BUREAUOF SOILS
U.
s. DEPARTMENT O F A G R I C U L T U R E , \$7ASHINGTON February 24, 1914
A NOTE ON THE QUANTITY OF BENZOIC ACID CONTAINED IN PRUNES AND CRANBERRIES Editor of the Journal of Industrial and Engineering Chemistry: Blthough it is well recognized that certain fruits contain relatively large amounts bf benzoic acid or its salts, data specifically stating the exact quantities are not numerous. I n connection with work in progress in this laboratory, it became desirable t o determine the quantity of benzoic acid in prunes and in cranberries. For the estimation of benzoic acid the method of Kriiger (Zeitschr. f. Untersuch. d. iVahr. u. Genusmittel, 1913, July) was employed, 50 grams of fruit being taken for a determination. From several duplicate analyses in each instance it was found that prunes as obtained in the market contained approximately 0 . 0 5 per cent benzoic acid Cranberries have a somewhat higher~benzoatecontent, benzoic acid t o the extent of 0.06 per cent being found. These results were furnished from the weight of sublimed
benzoic acid and by titration-the ing closely. SHEFFIELD
’
data in each instance agreeMORRISJ. RADIX
LABORATORY O F PHYSIOLOGICAL
Y A L E UNIVERSITY, N E W H A V E N ,
CHEMISTRY
CONN.
March 7 , 1914
BUREAU OF STANDARDS’ ANALYZED SAMPLES The Bureau of Standards is prepared to issue purified dextrose as a standard reducing sugar. The substance is free from ash and contains less than 0.1 per cent of moisture. In a n atmosphere of average humidity it is slightly hygroscopic, but if dried a t 70’ C., it retains less than 0.01 per cent of moisture. A certificate of analysis showing the quantity of remaining impurity accompanies the sample The purpose of the standard is t o assist in the unification of reducing sugar analysis by supplementing or replacing the use of invert sugar. It is, also, available for general sugar work. Further information may be obtained in Circular 25 on Standard Samples or Circular 44 on Polarimetry. FEE-Payable in advance: % for 70 grams or 83 for 140 grams.
PLATINUM THEFTS Editor of the Jourpial of Industrial and Engineering Chemistry: The following pieces of platinum have been stolen from the Chemical Laboratories of the University of Kansas i
-- ----_ CRUCIBLES
CRUCIBLES
No.
Approx. w t . . . . . . . 12 grams i . . . . . . . . 12 grams 2 7 . . . . . . . . 8 grams 1 . . . . . . . . 1 1 grams 5 . . . . . . . . 12 grams
3..
DISHES
No. Approx. w-t. No. Approx. wt. 4 . , . . . . . . 12 grams 6 . . . . . . . . 20 grams 1 0 . . . . . . . . 1 1 grams 7 . . . . . . . . 20 grams 2 5 . . . . . . . . 12 grams 2 4 . . . . . . . . 24 grams 3 3 . . . . . . . . 13 grams 2 5 . . . . . . . . 25 grams
All persons are warned against purchasing any of these pieces. The ownership of scrap platinum should be fully traced before the scrap is purchased. Any information leading t o the re-. covery of this material will be appreciated. E. H. S.BAILEY,Director of Chemical Laboratories UNIVERSITY OF
KANSAS, LAWRENCE
M a y 7 . 1914
Editor of the Journal of Industrial and Engineering Chemistry: Platinum valued a t some six hundred dollars disappeared from one of the Chemistry Laboratories of the University of Minnesota sometime on Monday, April 27, 1914. This platinum consisted of eighteen crucibles-Nos. 20, 21, 2 2 , 25, 26, 27, 29, 39, 40, 41 and 45 with covers of the same numbers and crucibles Nos. 35, 36, 37, 42, 44, 47 and 5 2 without covers; also one platinum dish t h a t weighed about 43 grams. If your readers hear of any platinum being offered for sale or have had any experience in the recovery of such property that might help us, we shall appreciate their immediate cooperation. J. C. POUCHER U N I V E R S I T Y OF M I N N E S O T A , M I N N E A P O L I S
May 5, 1914
PERSONAL NOTES Dr. J. A. Watkin, of the E. S. Public Health Service, has been sent to Pittsburgh by the Secretary of the Treasury t o investigate the effect of mill environment on the health of employees. This work, which constitutes a governmental innovation, will last until the end of the year. Dr. Francis H. Eckhardt, research chemist for the Grasselli Company, died a t the age of 46 on April 3rd a t his home in Elizabeth, N.J. Thomas H. Johnson, consulting engineer t o the Pennsylvania Lines West, died in Pittsburgh on April 16th. Prof. C. F. Chandler was the guest of honor at the 7th annual Dinner of the Columbia University Alumni Club of Philadelphia, April 17th, a t the Hotel Adelphia. The speakers were
Professor Chandler, C. H. Mapes, Lemuel Whitaker, Robt. Arrowsmith, G. B. Compton and -4rthur H . Elliot. Prof. -41an W. C. Menzies, now head of the Department of Chemistry a t Oberlin College, has been elected Professor of Chemistry a t Princeton University. Data collected recently by the College of Engineering of the University of Illinois show that of the 2,165 graduates, 1,933, or 89 per cent, are engaged in engineering work and t h a t only 173 or about 8 per cent have gone into other fields. Mr. H. de B. Parsons, of the Metropolitan Sewerage Commission, gave a n illustrated talk on the plans as proposed by t h e . Commission before the American Society of Mechanical Engi- neers, New York, May 12, 1914.
