T H E J O 1 7 R S a 1 L O F IA\-D17STRI.4L A S D E - V G I S E E R I S G C H E M I S T R Y
Map, 191j
sures higher t h a n ordinary on t h e explosibility of methane-air mixtures. T h e first experiments were made with pressures u p t o five atmospheres, b y raising t h e level bottle of t h e a p p a r a t u s high enough t o p u t the gas under this pressure. It was found t h a t increased pressure u p t o five atmospheres h a d no effect in changing t h e low limit of complete propagation. I n other words, t h e value, a b o u t j . j o per cent methane. is t r u e a t five atmospheres pressure. S U 11 MIA RY
When t h e initial temperature of methane air mixtures is j o o " C., t h e low limit of complete propagation of flame of t h e mixtures is between 3 ;j a n d 4 . 0 0 per cent methane. As t h e initial temperature is lowered from j o o o C., t h e low limit is raised until a t ordinary temperatures i t is about j . j per cent methane. Differences in t h e initial temperature of as much as 200' C . higher, shift t h e low limit only from 5 . j o per cent t o between 4.98 a n d j . I j per cent methane. T h e results are i m p o r t a n t in t h a t t h e y show t h a t pressure a n d temperature conditions m a y vary over rather a wide range without affecting t h e explosibility of methane-air mixturef . Inconsistent results t h a t have been obtained i n t h e laboratory b y different investigators on t h e limits of inflammation of methaneair mixtures cannot be explained on t h e basis of slight variations in temperatures a n d pressures. T h e y are better charged t o t h e nature of t h e source of ignition, method of ignition, size a n d shape of t h e containing vessel, a n d in some cases, inaccuracies in mixing a n d analyzing the gases. Since t h e low limit of complete inflammation for methane-air mixtures is not changed at pressures as great as five atmospheres, i t can be s t a t e d t h a t even i n t h e deepest coal mines t h e low limit is not altered from t h e limit a t ordinary temperatures. CHEMICAL LABORATORY, BUREAUO F hlINES
PITTSBWRGH
THE VARIATION IN COMPOSITION OF NATURAL GAS FROM DIFFERENT SANDS IN THE SAME FIELD' , B y G A. BWRRELLAND G. G. OBERFELL Received December 15, 1914
I n working on t h e composition of n a t u r a l gases from different p a r t s of t h e country, t h e authors have found t h a t n a t u r a l gases from different sands in t h e same field m a y differ appreciably in composition. Invariably t h e gas f r o m t h e shallower sand has contained less of t h e heavier paraffin hydrocarbons t h a n t h a t from t h e deeper sands. T h e most striking variation yet encountered has h a d t o d o with n a t u r a l gases from t w o different sands in a gas field near Trafford C i t y , Westmoreland C o u n t y , P a . a n d not far from Pittsburgh. T h e compositions of these gases follow: GAS F R O M Murraysville sand Elizabeth sand Depth of s a n d . . . 1700 f t . 2295 f t . Rock pressure. .. . . 190 lbs. per sq. in. 1000 lbs. per sq. in. CONSTITUENTS C o t CHI h-2 COX CHI CzHe Percentages .... . . Trace 9 8 . 8 1 . 2 Trace 94.0 5.2 '
.
.
Nt 0.8
It will be noted t h a t f r o m t h e shallow s a n d there was collected a sample of almost pure methane, while in t h e deeper sand there is contained in addition t o 1
Published by permission of the Director of the Bureau of Mines.
419
methane a n appreciable proportion of t h e higher members of t h e paraffin series of hydrocarbons. If one were t o assume a common source of origin for t h e natural gases in t h e t w o sands, t h e n b y some process of separation t h e gas in t h e upper sand has been freed of i t s ethane a n d higher paraffins. I t should be added t h a t t h e paraffins were analyzed by burning t h e m in oxygen. not b y fractional distillation; hence in t h e case of t h e gas from t h e deep sand, only t h e t w o predominating paraffins are shown. Undoubtedly small proportions of propane, t h e butanes, etc., were also present, as in t h e case of other natural gases containing methane a n d ethane. CHEMICAL LABORATORY, BCREACO F MIXES PITTSBURGH
A SIMPLIFIED FERROUS SULFATE METHOD FOR THE
DETERMINATION OF VANADIUM IN STEEL By GEORGET. DOUGHERTY Received October 17, 1914
I n t h e application of Johnson's' or similar methods for t h e determination of vanadium in steel, considerable difficulty is often experienced in producing a colorless or "old rose" shade with ferrous sulfate in t h e solution containing a n excess of permanganate after t h e ppeliminary oxidation of t h e 1-anadium. T o obviate this difficulty t h e following method has been developed. i n which this oxidation of t h e vanadium is effected by a sufficient q u a n t i t y of nitric acid alone or with a m monium persulfate. METHOD-Treat 2 t o 1 g. of t h e drillings in a j o o cc. Erlenmeyer flask, with 6 0 cc. of water a n d I O cc. concentrated sulfuric acid. After heating t h e solution nearly t o boiling. until t h e reaction is complete, a d d 40 cc. of nitric acid (sp. gr. 1.20) a n d boil thoroughly for I O minutes t o oxidize t h e iron a n d vanadium a n d t o expel t h e last traces of nitrous fumes. Cool t h e solution. a d d 6 0 cc. of cold sulfuric acid (I : z ) a n d dilute in a 600 cc. beaker t o 4 j o cc. Add 3 cc. of a freshly prepared I per cent solution of potassium ferricyanide, a n d t i t r a t e rather rapidly, with constant stirring, with 0.05 N ferrous ammonium sulfate, t o t h e appearance of t h e first d a r k blue color. T h e e n d point can best be observed b y looking through t h e side of t h e beaker t o w a r d t h e b o t t o m of t h e beaker placed directly before a window. Deduction of a blank of 0.4 cc. of t h e ferrous solution has been found necessary, a n d is independent of t h e weight of t h e sample, t h e presence of chromium, a n d of t h e carbon content u p t o 0.j per cent C . F o r steels with over 0.50 per cent C, t h e blanks are higher; a n d , moreover! with 4 g. samples of such steels, t h e e n d point is rendered indistinct b y a turbidity which appears toward t h e end of t h e titration. This difficulty m a y be avoided b y adding t o t h e solution immediately after t h e boiling with nitric acid as above, 60 CC. of I : P sulfuric acid a n d j t o 8 g. of ammonium persulfate (which i n t h e absence of silver nitrate will not oxidize t h e C r a n d M n ) , a n d continuing t o boil for I j minutes, so t h a t all nitrous oxides a n d hydrogen peroxide are expelled. (Before this second boiling, wash down with h o t water loose specks of t h e per1
C. M. Johnson, "Analysis of Special Steels."
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 C I A T E E R I N G CHEMISZ'RY
420
sulfatc which stick t o t h e glass.) Cool, dilute a n d t i t r a t e a s above. After such t r e a t m e n t t h e blank is 0.35 (instead of 0.4 cc.) for steels with under 0.5 per ccnt C, a n d 0.5 cc. for 0.60 t o 0 . 7 0 C, a n d 0.6 cc. for 0.90 t o 1.25 C steels. Thc blanks are t h e same with or without t h e persulfate treatment for steels of over 0 . j o per cent carbon. T h e ferrous ammonium sulfate solution m a y be standardized against 0.1 N perrnanganatc, t h e strength of which has been determined with sodium oxalate. T h e iron value of the permanganate multiplied b y 0.917gives t h e vanadium value. By this method t h e following results were obtained, t h e chromium in expts. 9, I O , 13 a n d 14 being added a s KzCrlOl before the solution of t h e steel. T h e following steels were employed: A-U. S . Bureau of Standorde Sample h70.24, containing 0.15 per cent V. 11.35 per cent C.and a trace of Ci. B-U. S. Bureau of Standards Sample No. 30, containing 0.21 per cent V. 0.37 per cent C.and 1.35 per cent Cr. C-A steel casting confaning 0.2 I S per cent V. 0.30 per cent C.and no Cr. D--A plain steel containing 0.85 per cent C. Ti-'1 plain steel cootnining 1.25 per cent C.
Vol. 7 , No. 5
investigators a n d their co-workers, we have come t o regard t h e soil organic matter not a s consisting of three of four compounds of rather indefinite properties, b u t a s being made up of a largc number of different organic compounds which result from plant and animal residues through t h e agency of t h e various chemical processes which are taking place in t h e soil. From various soils there have bcen isolated a n d identified up t o t h e present time, more t h a n half 3 hundred definite organic compounds. Among t h c various classes of organic compounds represented are acids, aldehydes, alcohols, amino acids, resins, cster6, glycerides, hydrocarbons, sugars, amines a n d other nitrogenous compounds. T h e methods by which these compounds have been isolated and identified are somewhat involved a n d ncetl not be considered here. The toxic effect on wheat plants of t h e various organic compounds which have bccn isolated f r o m various soils has been extensively srudied by Sclircincr' t h e work a n d his co-workers. With t w o
T A B LI-~IINIDIVM ~ DBTERMZNAT~ONS BY S I M P L ~ MBTXOD ED !%,eight of Persulfate Vanadium ~rmple added lnund EWt. Sample Grams Grains Gram h A
2
2
4
n
d
C
4
1
3
5 6 7
13 14
4
R
2
i
c
IF,
11:
0.148
0.146 0.206 0.208 0.21'5 0.286 0.222
C
?3%
I.Jv"Cr 1
From these results i t is apparent t h a t in general for such materials, t h e method is accurate t o 0.01 per cent vanadium. If chromium also is t o he determined, i t is determined in a separate portion of t h e sample, using a n y of t h e usual volumetric methods. AYERICAN STBBL~ O U N D R I K S . CIIICAGO
-____
THE EFFECT OF CERTAIN ORGANIC COMPOUNDS ON WHEAT PLANTS IN THE SOIL-PRELIMINARY PAPER BY Faso W. UPSONA N D A. R. POWBLL Received March 20. 1915
In recent years our knowledge of t h e chemical nature of soil organic matter has been greatly extended through t h e work of a number of investigators, chief among whom are Jodidi a n d t h e several workers in soil fertility investigations of t h e United States Bureau of Soils. A very complete historical account of t h e work on soil organic, m a t t e r a n d of t h e older views regarding i t has been presented by Schreiner a n d Shorey' a n d b y Jodidi.z Through t h e work of these 1
Bull. 63,Bur. oi Soils, U.S . Dept. Agr.. p. 21. Biockrm. Bull. 3, 17.
2
3 PL*TC
4
I
by thesc investigators on the toxic effect of organic compounds has bcen determined by growing plants for short periods i n distilled water culturcs containing t h e various compounds, The organic ,compounds studied are either those which have been isalat.ed f r o m t h e soil or those which may result through t h e breaking down of plant a n d animal residues. Many of t h e compounds studied have been shown t o be more or less toxic t o wheat plants in comparatively low concentrations, 1 0 - 2 0 0 parts per million of solution. Some few have heen found beneficial t o t h e growth of wheat plants in water solution. In many cases t h e addition of fertilizer salts t o t h e culture solution has partially or completely overcome t h e toxic effects of t h e organic compounds. While a knowledge of t h e effect of these compounds on t h e growth of wheat seedlings in water solution is of t h e greatcst importance, nevertheless we should I A Summary of the effect of varioun organic compounds en growth 1% given in Bull. 81, Bur. of Soils. U. S. Dept. A=.. p. 7 0 . 2 Sehieiner and Skinner have studied the effect of cumarin (Bull. 17, Bur. Soils, p. 16) and of ralieylic aldehyde, U. S. Depf. Agr. (Bull. 108, 5. IZ), an =heat Plants in the mil.
