July, 19x6
T H E J O U R N A L OF IiVDUSTRIAL A N D ENGINEERING CHEMISTRY
63 7
of t h e barometric readings fell below 7 2 0 mm. Consequently, it became necessary t o work out a table of values for these lower pressures. The same formula, as given in the article cited previously, was used with t h e additional factor for converting t h e results directly t o milligrams of carbon, since i t was in terms of t h e element t h a t the final results were desired. T h e accompanying table is based upon t h e formula as used b y Parr with t h e addition just mentioned. Values for pressures of 708-716 mm. and temperatures 2026’ C. were worked out entirely b y t h e formula. T h e remaining values were interpolated from t h e table of values for carbon published in t h e pamphlet which WEIGHT OF CARBON I N MILLIGRAMS PER CUBIC CENTIMETER OF For Bar. 700 t o 718 mm. and 10 to 30’ C.
coz
Corrected for aqueous vapor a n d barometer readings, glass scale Calculated from 1.976 = wt. 1 liter COS a t 0’ C. and 760 m m . a t 41O L a t .
P= t o C.
10 11 12 13 14 15
700 0.4714 0.4693 0.4670 0.4648 0.4626 0.4603
702 704 0.4728 0.4707 0.4684 0.4662 0.4639 0.4616
706
708
710 712 714 0.4782 0.4796 0.4761 0.4774 0.4738 0.4752 0.4716 0.4729 10.4693 0.4706 0.4670 0.4683
716
71R
i 7 0.4557 0.4570 0.4584
T h e chart is constructed as follows: For a t a n k of a certain diameter, t h e areas of t h e cross sectional segments are calculated for each inch in depth. A curve is then plotted with t h e inches as abscissas, and t h e areas as ordinates. Next, for a t a n k of definite length, a curve is plotted with areas of cross sectional segments as ordinates and volumes in gallons as abscissas. ( I t may be noted t h a t t h e curves of “cons t a n t length ” are straight lines passing through t h e origin. Hence it is sufficient t o determine one point for each of these curves.) I t is convenient t o give t h e gallons on a line below t h a t on which t h e inches rise are given, in order t o avoid confusion. The method of using t h e chart may be best shown by a specific problem on t h e diagrammatic curves shown in the figure. Let it be required t o find t h e contents of a t a n k z j ft. long, I O f t . in diameter, a n d contents 1 2 in. deep. Referring t o t h e figure, follow the ordinate rising from 1 2 in. t o its intersection with t h e curve marked diam. I O . Then proceed horizontally t o the line L z j , and vertically below is the required number of gallons. ROAN~ C O U N T A ITENNESSEE K,
A TABLE FOR VALUES OF CARBON IN CARBON DIOXIDE By HOWARD LOOMIS Received M a ch 24, 1916
I n t h e J . A m . Chem. S o c . , 31 (IQO~),2 3 7 , in a n article entitled “ T h e Weight of Carbon Dioxide with a Table of Calculated Results,” b y S. R. Parr, there is given a table of values for carbon in carbon dioxide for barometric pressures of 720-770 mm. and temperatures of 10-30” C., calculated in accordance with t h e formula given and discussed in t h a t article. I n making determinations of total carbon in soils in this laboratory recently, it was found t h a t very many
18 19 20 21 22 23
0.4534 0.4547 0.4560 0.4510 0.4523 0.4536 0.4489 0.4502 0.4515 0.4465 0.4478 0.4491 0.4442 0.4455 0.4468 0.4418 0.4431 0.4444 0.4393 0.4406 0.4419 0.4432 0.4445 0.4458 0.4472 0.4485 0.4498 0.4434 0.4369 0.4382 0.4395 0.4409 0 4344 0.4357 0.4370 0.4383 0.4319 0.4332 0.4345 0.4357 0.4293 0.4306 0.4319 0.4268 0.4281 0.4293 0.4331 0.4242 0.4255 0.4267 0.4305
24
ij 26 27 28 29 30
n.451 I
usually accompanies the Parr Total Carbon apparatus and which is based on t h e table of values for carbon dioxide as published in the preceding Journal article. These interpolated values were in many cases checked b y t h e formula for accuracy, as were many of t h e values in t h e table in the little pamphlet from which t h e interpolations were made. These values are worked out for Lat. 41 O, t h e same as the original table of values. AGRICULTURAL EXPERIMENT STATION BROOKINGS. SOUTH DAKOTA
A RAPID METHOD FOR THE ACCURATE DETERMINATION OF TOTAL CARBON IN SOILS By ROBERTM SALTER Received March 13, 1916
Most methods in common use for the determination of total carbon in soils are not sufficiently rapid t o be well adapted t o routine laboratory practice. This fact led the writer t o attempt a n adaptation of t h e direct combustion method, as now used in t h e rapid determination of carbon in steel, t o t h e determination of total carbon in soils. The method evolved and successfully used in several hundred determinations is a n adaptation with modifications of the method described b y Fleming’ for t h e rapid determination of carbon in iron and steel. I t depend? upon the direct combustion of soil in a current of oxygen, the gases being dried by phosphoric anhydride and t h e carbon 1
The Iron A g e . 93, 64-66.
