664
T H E J O U R S A L OF IlVDI;STRI.4L A.VD EA\;GIA-EERISG C H E M I S T R Y Found Percent Calcium. . . . . . . . . . . . . . . . . . 7.51 Arsenic.. . . . . . . . . . . . . . . . . 9.43 Sulfur.. . . . . . . . . . . . . . . . . . 14.24
Theoretical Theoretical Found Caa(AsS& CadAsSdz Percent Percent Percent 7.61 9.43 14.29
7.51 9.37 12.01
7.51 9.37 16.01
For the figures showing the comparative fungicidal values of lime-sulfur solution and the solution of calcium thioarsenate the authors are indebted t o Dr. Chas. Brooks of the United States Bureau of Plant Industry. The spore of Penicillium glaucum placed in a I per cent sugar solution t o assist germination was used in the tests. The following figures are averages of duplicates and express the per cent of germinating spores after seventy-two hours. Blanks were run and in all cases gave 50 per cent germination. PENICILLIUM PLACEDDIRECTLY IX
Specific gravity of solutions 1.00125 1 ,000625 1.0003125
THE
SOLUTIONS ON GLASS
Per cent germination Per cent germination in lime-sulfur in calcium thiosolution arsenate solution 1 None None 20 12
1
SOLUTION SPRAYED ON GLASSAND DRIEDBEFORE ADDING PENICILLIUM Specific gravity of solutions 1.01 1.005 1 ,0025 1.00125
Per cent germination Per cent germination on dried lime-sulfur on dried calcium solution thioarsenate solution 35 5 50 Sone 70 7 65
25
The figures show that calcium thioarsenate solutions are many times more powerful as a fungicide than lime-sulfur solutions of the same density. For the latter figures for lime-sulfur solution it may be noted that the very dilute spray acts as a stimulant t o germination. But since in practice the solution having a specific gravity of I . 0 2 to I. 04 is sprayed it has little practical bearing. The preceding work was done in the winter when the toxic effect of the solutions on foliage under growing conditions could not be determined. I n the spring, solutions of calcium thioarsenate of various densities were sprayed on new foliage of the apple tree. Solutions ,of I .02 and I . O I specific gravity killed new growth and the leaves completely. Solutions of 1.005 and 1.0025 specific gravity did not kill new growth but damaged all the leaves, killing many. Solutions of I . O O I 25 and I . 0 0 0 6 2 j specific gravity did not kill the leaves but damaged many of them. The solution of I . 0 0 0 3 1 2 5 specific gravity did only slight damage, causing small spots on some of the leaves here and there, but enough to forbid the use of even this density on apple trees. Weaker solutions were held t o offer no advantages for use. CONCLUSIONS
Calcium thioarsenate is a soluble arsenical compound that is comparatively inexpensive and that has strong fungicidal properties. It cannot be used in effective densities for spraying apple trees because
Vol. 5 , No. 8
of the injury it causes t o the foliage. For the spraying of plants less sensitive t o arsenic than the apple tree it may be found advantageous. CHEMICAL LABORATORY h-EW HAMPSHIRE COLLEGE DURHAM
THE
OF PHoSPHoR*C IN HYDROCHLORIC ACID
INSOLUBLE
B y WILLIAMH . FRY^ Received June 27, 1913
The official method2 for the analysis of soils is accomplished by digesting a known quantity ( I O grams) of the soil in hydrochloric acid, specific gravity I . I I 5 , for ten hours on a steam or water bath and then analyzing the solution thus obtained for the constituents m-hich it is desired to determine. I t is almost a matter of common knowledge that this method does not invariably give the total amount of phosphoric acid present in the soil analyzed. A few figures will illustrate this. I n a study of the chemical composition of Maryland soils, Veitch3 found the values given in Table I. An examination of the foregoing table shows t h a t in these soils from 4 per cent t o I O O per cent of the total amount of phosphoric acid present went into solution in the acid used. I n only two soils was the total amount extracted. The average percentage extracted is about 5 7 . 6 per cent, a little over half. Ellett and Hill4 give the comparative values in Table I1 for various Virginia soils. I n every case except one, i. e . , the Coastal Plain Sandy Loam surface soil from Caroline County, the acid extraction method gave lesser amounts of phosphoric acid than the total amount obtained by the fusion method. The case in which this is not so can probably be explained by unavoidable errors of sampling. I t is obvious, granting that equal amounts of phosphoric acid were present in the quantities of soil used in the two separate determinations, that the total amount cannot be less than the amount extracted by the acid digestion. This exceptional case must be discarded as proving nothing a t all. These two tables simply illustrate the fact that the official method does not always give the total amount of phosphoric acid present in the soil. There are two explanations for this. Either the phosphoric acid not extracted by the official method is present in the soil in compounds insoluble in the acid used; or else i t is present in a soluble form which is protected from the action of the acid. We have no means of directly testing the first of these possibilities. However, a comparison of Dana5 and Brush and Penfield6 resulted in the finding of 1 Scientist in Soil Laboratory Investigations, Bureau of Soils. 1J. S Department of Agriculture. 2 Bureau of Chem.. Bull. 107 (revised), pp. 14, 15 (1912). 3 Maryland Agr. Expt. Sta.. Bull. 70 (1901). 4 Va. Polytech. Inst., 4gr. Expt. Sta., Bull. 200 (1912). 5 “System of Mineralogy.” 6 “Determinative Mineralogy and Blompipe .4naiysis.”
Aug., 1913
T H E JOL7RAYALOF 1.VDUSTRIAL A N D ENGIATEERI.\-G
several mineral phosphates which these authorities state are insoluble in hydrochloric acid. Among these minerals mere xenotine, a n yttrium phosphate ; variscite, a hydrated aluminium phosphate; lazulite, a hydrated iron-magnesium-aluminium phosphate ; and others. Although none of these insoluble phosphates have been found in any of the large number of soils analyzed mineralogically by this bureau, i t is still possible that some of them do occur in soils. If they do occur in soils, the quantity present must be extremely small. It is also possible that some of the insoluble phosphoric acid IS present in minerals which do not carry phosphoric acid as an essential ingredient, or i t may be present in other forms which the interaction in the soil solution might give rise to. ,4s can be seen by referring t o the two tables below, the quantity of this insoluble material must be very small indeed, even granting that all of the phosphoric acid not extracted by the oficial method is in insoluble forms. TABLE I-PERCESTAGE O F TOTAL P H O S P H O R I C ACID SOLUBLE SP. GR. HSDROCHLORIC h C I D . MARYLASD SOILS Potomac clays, barrens.. . . . . . . . . . . . . . . . . . . Serpentine, barrens.. . . . . . . . . . . . . . . . . . . . . . Columbian sandstone, . . . . . . . . . . . . . . . . . . Trenton limestone.. . . . . . . . . . . . . . . . . . . . . . Triassic sandstone.. . . . . . . . . . . . . . . . . . . . . . Catskill sandstone.. . . . . . . . . . . . . . . . . . . . . . . . . . . . Helderberg limestone.. . . Gabbro. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gneiss.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hudson River shale.. . . . . . . . . . . . . . . . . . . . . . . Corn and wheat soil, eastern shore.. . . . . . . . . . . . Columbia, corn and wheat.. . . . . . . . . . . . . . . . . . . . Chesapeake, corn and w h e a t . , . . . . . . . . . . . . . . . . . Chesapeake, tobacco., . . . . . . . . . . . . . . . . . . . . . . Truck soils eastern shore.. . . . . . . . . . . . . . . . . Columbia, truck, southern I i a r y l a n d . . . . . . . . . . .
IY
1.1 15
34.0 34.2 64.2 65.0 i4.5 4.0 61.7 100.0 69.4 100 0 60.7 3i 5 S5 0 62 0 32.0 34 2
TABLE 11-COnlPARISOS O F TOTAL PHOSPHORIC ACID A S D THAT EXTRACTED B Y 1 . 1 1 5 SP. GR. HYDROCHLORIC . ~ C I D . YIRGISIAS ~ L S
Total present Limestone soil, Allegheny C o . . . . . . . . . . . . . . . Great Valley limestone clay l o a m . . . . . . . . . . . . . . Piedmont bright tobacco soil, Pittsylvania Co.. . Piedmont subsoil, Fairfas C o . . . . . . . . . . Piedmont soil. Fairfax Co.. . . . . . . . . . . . Piedmont gray soil, subsoil, Appomattox. . . . . . . . Piedmont gray soil, surface soil, Appomattox. . . . Piedmont chocolate soil, subsoil. .Appomattos Co. Piedmont chocolate soil, surface soil, Appomattox
Co . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Piedmont “Red Lands” soil. surface soil, Albemarle C o . , . . . . . . . . . . . . . . ... Coastal plain sandy loam, surface soil, Caroline Co. Coastal Plain sandy soil, water rrorks soil, Norfolk Coastal Plain sandy soil, Diamond Spring soil. A-orfolk.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
0.088
Percentages phosphoric acid extracted by 1.115 sp. gr. H C1 0.06
0.133 0 029 0.1026 0.1218 0.058 0.0826 0 118
0.02 0.098 0 099 0 045 0.074 0 076
0 185
0.09
0.404s
0.113 0.03 0.04
0.0183 0.063 0.057
0.0;
0.03
In regard to the second possible explanation: mineralogical analyses have shown t h a t a very large number of soils contain apatite, a hydrochloric acid-soluble calcium phosphate, enclosed in quartz grains. Soils known to contain apatite thus enclosed in quartz were subjected t o a n acid digestion1 according t o the 1
The acid digestions were made b y MI. R . F. Gardiner, of this Bureau.
CHE-IiISTRY
665
official method : and the residues xere examined mineralogically. Apatite was found still inclosed in quartz, and was apparently unattacked. This explains the insolubility of a t least a large part of the phosphoric acid. S U 11N A R Y
There may be a very minute quantity of phosphoric acid in soils in hydrochloric acid-insoluble compounds, b u t a large part of the phosphoric acid not extracted is present in a soluble form, i. e . , as apatite, which is protected from the action of the acid. BUREAU O F SOILS
r. S. DEPARTMENTO F
.%GRICULTURE
WASHINGTON, D. C.
ANALYSES OF CONFECTIONERS’ GLUCOSEL By
EDWARD GVDEMAX
Determinations of the mineral constituents of confectioners’ glucose representing over 1000 market samples examined during the years 1 9 0 2 to 1913 were submitted in chart form, the curves showing the maxima, minima and averages for total ash, chlorides, sulphurous oxide and copper. The data submitted show that no fixed ratio exists between the amounts of any of these ingredients. The chlorides, calculated to sodium chloride, approximate two-thirds of the total ash. The sulphurous oxide (SO,) seems t o increase and decrease inversely with the other ingredients, but this variation is not definite, as the age of the glucose influences the amount of sulphurous oxide present, a gradual reduction taking place. The fluctuation in the amounts o f all ingredients is so large that none of them can be taken as indicating the quality of the product, and also show that no fixed figures can be taken as standards for commercial glucose or corn syrup. v A R I A T I O I i S I S T H E 1\fAXIMA,
3flYl3l.X A S D
AVERAGES
Total ush 84-158 parts t o 10.000 parts glucose (D. S . ) 30- 50 parts t o 10,000 parts glucose (D. S.)
Maxima: Minima:
_ _
.Averages: 52- 52 parts t o 10,000 parts glucose (D. S . )
ChloTides calculatcd t o S a C l 68-92 parts to 10.000 parts glucose ( D . S.! 18-38 parts to 10,000 parts glucose (D. S.)
Maxima: Minima:
__
Averages: 36-56 parts t o 10,000 parts glucose (D. S . )
SulBhurous oxide 160-340 parts t o 1,000,000 parts glucose (D. S.) 10-165 parts t o 1,000,000 parts glucose (D. S.)
Maxima: Minima:
-_
Averages:
60-240 parts t o 1,000.000 parts glucose (D. S.)
CopBer Maxima: Minima:
4.5-7.0 parts t o 1,000,000 parts glucose (D. S.) Trace-1 . O parts t o 1,000,000 parts glucose (D. S.)
__
Averages: 1.5-3.5 parts t o 1,000,000 parts glucose (D. S . ) 1 Paper presented a t the Milwaukee meeting of the American Chemical Society. March, 1913.
