f
T H E JOURNAL O F INDUSTRIAL A N D ENGINEERING C H E M I S T R Y .
74
Mar.,
1911
stirrer B was constantly raised ahid lowered through I n every case where the depression of the freezing the solution. The freezing point was indicated b y a point remained within the limits cited in the tables, sudden rise in the mercury when the substance solidified, the vinegar was found t o analyze up t o the required owing t o heat liberated when the substance was con- standard. As the result of these experiments the writer recomverted from the liquid to the solid state. The entire determination required a n average of twenty minutes. mends t h a t chemists associated with vinegar or pickFor analyses the vinegar was measured rather than ling and preserving factories establish a depression weighed so as t o avoid the loss usually incurred b y of the freezing-point range for each vinegar manuevaporation when weighing liquids. The volume in factured or used b y them. cubic centimeters was then multiplied b y the specific One inducement for giving the method a trial is gravity t o obtain the weight in grams. . t h a t i t requires but twenty minutes for each deterFollowing are the tables which show the data ob- mination. Every vinegar chemist knows t h a t a comtained: plete analysis requires a much greater period of time. PREPARED MALT VINEGAR.
Number Depression of of freezing sample. point. 19 1.13"C. 20 1.13OC. 21 1.13'C. 22 1.13"C. 23 1.14°C. 24 1.14OC. 25 1.14"C. 26 1.14OC. 27 1.14"C. 28 1.14OC. 29 1'.13'C. 30 1.13'C. Average,
1,135' C.
Number Depression of of freezing sample. point. 31 2.14"C. 32 2.14OC. 33 2.14'C. 34 2.14'C. 35 2.10oc. 36 2.10°C. 37 2.10oc. 38 2.16'C. 39 2.20oc. 40 2.2OoC. 41 2.2OoC. 42 2.20'C. Average,
2.15
O
C.
Acidity. HCzH302. Per cent. 5 .O 5 .O 5.0 5.1 5.1 5.1 5.1 5.1 5.1 5.1 5 .O 5 .O
--
Solids. Per cent. 1.6 1.6 1.6 1.6 1.8 1.8 1.8 1.8 1.7 1.7 1.7 1.7
Ash. Moisture. Per Per cent. cent. 0.2 93.4 0.2 93.4 0.2 93.4 0.2 93.3 0.2 93.1 0.2 93.1 0.2 93.1 0.2 93.1 0.2 93.2 0.2 93.2 0.2 93.3 0.2 93.3
- - _ _
5.06 1.7 0.2 DISTILLEDVINEGAR.
93.24
Specific gravity. 1.13 1.13 1.13 1.13 1.14 1 .14 1.14 1.14 1 .13 1.13 1.13 1.I3
1.133
Acidity. HCzHaOz. Per cent.
Solids. Per cent.
5.3 5.3 5.3 5.3 5.2 5.2 5.2 5.3 5.5 5.5 5.5 5.5
0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.2 0.2 0.2 0.2
0.02 0.02 0.02 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02
94.5 94.5 94.5 94.5 94.6 94.6 94.7 94.6 94.3 94.3 94.3 94.3
1.006 1.006 1.006 1.006 1.006 1.006 1.006 1.006 1.007 1.007 1.007 1.007
0.18
0.02
94.48
1.0063
5.35
Ash. Moisture. Per Per cent. cent.
UNIVERSITY OF PITTSBURGH. DEPARTMENT OF CHEMlSTRY.
_ _ - - _ _
Specific gravity.
-
CIDER VINEGAR.
Number Depression of of freezing sample. point. 1 2.65OC. 2 2.65'C. 3 2.65'C. 4 2.65'C. 5 2.7OoC. 6 2.7OoC. 7 2.67'C. 8 2.68'C.
--
Average.
2.67' C.
Number Depression of of freezing sample. point. 9 3.35oc. 10 3.35oc. 11 3.35oc. 12 3.35oc. 13 3.30°C. 14 3.3OoC. 15 3.30°C. 16 3.30°C. 17 3.37'C. 18 3.37'C. Average,
3.33 O C.
Acidity. Solids. HC2H302. Per cent. Percent. 5.8 2.6 5.8 2.7 2.6 5.8 2.6 5.8 5.8 2.9 2.9 5.8 5.8 2.8 5.8 2.8
Ash. Moisture. Per Per cent. cent. 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3
91.6 91.5 91.6 91.6 91.3 91.3 91.2 91.2
0.3
91.41
-
- _ _ -
5.8
2.73
MALT VINEGAR. Acidity. Solids. Ash. Per HC2HaOl. Per Per cent. cent. cent. 0.2 6.1 1.9 1.9 0.2 6.1 0.2 6.1 1.9 0.2 6.1 1.9 1.9 0.2 6.0 1.9 0.2 6.0 1.9 0.2 6.0 1.9 0.2 6.0 1.9 0.2 6.1 1.9 0.2 6.1
-
-
-
6.06
1.9
0.2
Specific gravity. 1.15 1.15 1.15 1.15 1.16 1.16 1.16 1.16
--
1.155
Moisture. Per Specific gravity. cent. 92.0 1.20 92.0 1.20 92.0 1.20 92.0 1.20 92.1 1.I8 92.1 1.18 92.1 1.19 92.1 1.19 92.0 1.20 92.0 1.20
-
92.04
1.194
A BACTERIOLOGICAL METHOD FOR DETERMINING AVAILABLE ORGANIC NITROGEN. By J. M. MCCANDLESSAND F. C. ATKINSON.
This laboratory was called upon last summer to report upon the availability of the ammonia in two samples of material which we will call "Nitrolene and Ammolene:" the nitrogen in these materials was derived exclusively from leather, but they had been treated b y a special process for rendering the leather soluble and available. We analyzed the two materials b y the Pepsinacid method and b y the Neutral and Alkaline Permanganate methods. The results were flattering t o the materials and on the whole quite satisfactory; b u t we desired t o obtain for our clients evidence more in the nature of a crop or pot test: there was, however, no time t o make such tests, therefore, we decided t o make a soil extract, and digest our materials in this solution for the limited period of time a t our disposal. At t h a t time we had no knowledge of the fact t h a t Dr. Lipman, of New Jersey, had published a paper on " Bacteriological Methods for Determining the Available Nitrogen in Fertilizers."' If we had, we should probably have followed the method outlined b y him, b u t we used the following method: Total nitrogen was determined in samples of cottonseed meal, nitrolene and ammolene with the following results: Total nitrogen as ammonia..
Cottonseed-meal. Nitrolene. Ammolene. Per cent. Per cent. Per cent. -8.20 9.40 3.42
........
One-gram portions of each were weighed, treated on filters with boiling water, and the filtrate made up t o 5 0 0 cc.; aliquot portions were taken and the total nitrogen in the aqueous solution determined ; the nitrogen existing as free and saline ammonia was also estimated in separate portions b y distillation with magnesia ; the following results were obtained : Cottonseed-meal. Nitrolene. Ammolene. Per cent. Per cent. Per cent. Nitrogen (in terms of "a), in the 1 .Ol 5.79 2.49 aqueous solution.. Percentage of total nitrogen in the 61.94 72.8 materials, soluble in water. 12.3 Free and saline ammonia in the 0.28 0.45 0.88 aqueous solution.. Water-soluble organic nitrogen (in 0.73 5.34 1.61 terms of ammonia).
................ ......... ................
...............
1
THISJOURNAL, 2, 146.
,
LOEB ON VARIATION I N SPECIFIC HEAT OF W A T E R S . A sample of soil was procured, and a definite quantity shaken up with some of each of the aqueous solutions and filtered; definite portions of the filtrate were then incubated for a period of 2 1 0 hours a t 38-40' C. One series of flasks was incubated under aerobic conditions loosely stopped with cotton wool ; another series under anaerobic conditions in flasks with the surface of the liquid protected b y oil. I n all these latter flasks the tests for nitrates and nitrites were practically N I L . In the aerobic flasks the ammonia produced b y the action of the soil bacteria, from the water-soluble organic nitrogen was: After After After After
lapse lapse lapse lapse
of of of of
Cottonseed-meal. Nitrolene. Ammolene. Per cent. Per cent. Per cent. 40 hours 0.00 1.12 1.10 1.56 0.42 88 hours. , . , , . . . . . . . 0 .OO 0.02 0.37 0.08 160 hours.. . . . . . . . . 0.00 0.20 0.30 210 hours.. . . . . . .
. .
.. . . .. ... . ... . 0.22
_ .
3.35
1.60
The experiment was stopped at this point b y exhaustion of the flasks prepared. As will be seen, the action on the cottonseed-meal solution was slow as compared with the others. I n the case of the ammolene, practically all of the water-soluble organic nitrogen had been converted into ammonia after 88 hours. In the case of the nitrolene, which was much richer in organic nitrogen, about 63 per cent. of the soluble organic nitrogen had been converted into ammonia in 2 1 0 hours, b u t the action then became very slow, presumably due t o the toxic action of a n excess of ammonia on the organisms producing it. A solution was now prepared containing in I liter, potassium phosphate I gram, sodium chloride 2 grams, magnesium sulphate 0 . 5 gram, and calcium chloride 0.050 gram; this solution was shaken up with a definite quantity of the soil and filtered, 50 cc. of the filtrate was placed in small flasks along with the filter papers containing the residues from the treatment of one gram of each material with hot water. After incubating these residues for 2 6 days there remained in the Cottonseed-meal, Nitrolene. Ammolene. Per cent. Per cent. Per cent. Insoluble ammonia 2.09 2.74 0.60 Ammonia rendered 5.10 0.87 0.33 Total solubility in terms of ammonia. 6.11 6.66 2.82 Percentage of solubility on total introgen 74.5 70.9 82.5
...
An interesting observation was made in connection with the incubation of the insoluble residues of the nitrolene and cottonseed-meal. After 5 days' incubation, the contents of a set of these flasks were filtered, and in the filtrates we found: Cottonseed-meal. Per cent. Free ammonia.. . . .
1.25
0.13
-Also, organic nitro of ammonia). . . .
Lost
0.13
1 .OO
0.20
0.40
0.25
After 8 days, similar analyses showed free ammonia Also, organicnitrogen rendered soluble (in terms of ammonia). . . . . . . . . . . , , . , . .. .
.
'
Nitrolene. Per cent.
.. . . . . . . . . . . . .
I n other words, the bacteria had produced from the insoluble proteid matter of the cottonseed-meal, 2.25 per cent. of ammonia, and had rendered 0.4
I75
+
per cent. per cent. in the lost determination of the insoluble organic nitrogen soluble; in the case of the nitrolene, in 8 days they had produced in like manner from the insoluble proteid matter 0.33 per cent. of ammonia, and had converted o 38 per cent. of the insoluble organic nitrogen into a soluble form. Evidently there are two distinct processes, first, the bacteria convert the insoluble proteids into a soluble form, and it must be in this soluble form before they can decompose it into ammonia. I t would doubtless be a matter of interest t o the professional bacteriologist t o ascertain whether the ammonifying organisms also possess the power of rendering proteid matter soluble, or whether this function is performed by some other organism. The method seems worthy of further application as a test of the availability of doubtful nitrogenous materials, as the conditions are completely under the control of the operator, and in this respect, and in the shortness of the time required, have a great advantage over crop, or pot tests, while the results are equally as convincing, since there is little or no doubt t h a t the ammonification of organic nitrogenous substances b y the intervention of the soil bacteria precedes their nitrification and absorption as plant food.
------
INFLUENCE OF VARIATION I N SPECIFIC HEAT OF WATER ON CALORIMETRY OF FUELS. By LEOLOEB.
Along with the values of the heats of combustion of the various substances used in calorimeter standardization which accompany samples of cane sugar sent out b y the Bureau of Standards is a short account of the experiments of Fischer and Wrede.' Mention is made of the fact that their values are given in terms of electro-mechanical units, since the specific heat of water was not determined more closely than one part in two thousand. Yet as early as 1 9 0 2 , W. E. Barnes published in the Physical Rewew. 15, 7 1 , the results of his experiments a t McGill University on the specific heat of water. An electrical method devised b y Professor Callendar and Dr. Barnes was employed t o get the data from which the values were computed. The heat unit used was the amount of heat required t o raise the temperature of I kg. of water from 15-16' C. Other values have been determined by Dietericil but his method does not appear t o have the certainty of Barnes; nor are his results as consistent. I n general Dieterici's results are higher than those of Barnes, but this is in part due t o the fact t h a t his heat unit was the Bunsen Calorie. Indeed, the failure t o agree on a universal heat unit is the cause of frequent inconsistencies in calorimetry. At least three standards are recognized : I . The Calorie as defined above. 2 . The B. t. u.: the amount of heat required to raise 1 Sztzunpsberzchte der Preusswchen A kademze Berlzn, 6 , 129 (1908) 2 Annalen der Physzk, (4)18, 573 (1905).
der
Wzssenschaften,
j
