TABLE111-DETERIIKATIOS
Number
OF
ALCOHOL IX DISTILLATES FROJI BEER
Alcohol bq. PYCnometer Per cent
Alcohol by refrac-
tometer Per cent
2 . . . . . . . . . . . . 1.22 3... . . . . . . . . . .1. o i 4. . . . . . . . . .. 3 sz 5,..
. . . . . . . . . . 4 , 14
6. . . . . . . . . . . . .3.32 i . . . . . . . . . . 1 31 8
Difference in 1/100 per cent
. . . . . . . . . . . .3 . 6 0 . . . . . . . . . ..1.15
9..
10... . . . . . . . . . . 3 . 6 8 1 1 . . . . . . . . . . . .3 45 1 2 . . . . . . . . . . . . 3 33 1 3 . . . . . . . . . . . ..3.21 14... . . . . . . . . . . 3 . 2 0
3.87 3 99 3 81 3.67 4 .oo 3.20 4.25 3.64 4,lO 3,67 3,41 3.30 3.15 3.15
c_-
-!-
-
13 23
..
..
19 15 14
..
12
..
..
6 , .
4
5
.. ..
1 4
3 6 5
..
.. .. ..
mann and Steinmann checks the pycnometer quite well. The use of the immersion refractometer for the direct analysis of beer according to the method of Ackermann or Danzer is the last question to be discussed. Do the results pu3lished herewith, as well a s those made public by the authors cited, justify the adoption of the rapid, short refractometer method in place of the decidedly longer and more cumbersome pycnometer analysis? We believe that it has been shown that the agreement between the results of the two analyses is practically as good for American beers made from malt and adjuncts as it is for European all-malt beers. I n Europe, i t is to-day the opinion of most brewing chemists that the results obtained with the refractometer are perfectly reliable for factory control. Where questions of law, or exact food chemistry are involved. opinions differ considerably. Even in such cases, hon-ever, the variations between results obtained by the two methods rarely exceed the limits which must be permitted even in a judicial controversy. It seems, therefore, that the brewing chemist here in America is amply justified in adopting the refractometer method of beer analysis, and only reverting to the old method in legal cases or controversies between analysts. In conclusion, the author wishes to acknowledge his thanks to Mr. Theodor Ihnen, chemist for the First Scientific Station for the Art of Brewing, for numerous beers analyzed in gathering material for this paper. CHEMICAL LABOR~TORY THE ART OF SREWIKG
FIRSTSCIESTIFIC STATION FOR
A-EW T O R H
CALCIUM THIOARSENATE AS A SPRAY S . H. KATZAND P. D . BUCKMIISSTER
Received June 23, 1913
Since the inception of this work, Ellis has patented (U. S. Pat., No. 1,002,247) “ a composition for agricultural spraying purposes, comprising a soluble form of alkali or alakaline earth polysulfids preferably in conjunction with a thioarsenate or other thioarsenical compound as a strengthening material and preferably with a binding or adhesive material.” Parsons] 1
THISJOURNAL, 4, 183.
has said of arsenic. “ I t is used in large quantities in combination with lead as an insecticide and it would seem worth while to have experiments inaugurated to determine if arsenic sulfid or calcium sulfarsenite, both of which are probably quite harmless to plants, may not be substituted as an insecticide. giving a much cheaper material, using more arsenic and conserving lead. I t should be noted particularly that any proposed insecticide must be effective as a poison but must not injure the foliage of the plant upon which it is placed.” The above expresses in part the original purpose of this work, but it was also hoped to produce a substance which would be effective as a fungicide as well as an insecticide and scalecide, for calcium thioarsenate resembles, a t least in chemical composition. the polysulfids of calcium, which, as the lime-sulfur solutions, are nom- used as fungicides. Calcium thioarsenate is a soluble substance, and it is well known that soluble arsenic in the arsenicals now used as sprays is injurious to foliage. But the thioarsenates are quite different in their chemical nature from the arsenites or arsenates and it was expected that there might be a corresponding difference in their physiological action on foliage. Also the thioarsenic compounds readily decompose on exposure. yielding in part insoluble arsenic trisulfid. From these considerations it was hoped that the material could be safely used as a spray. In his patent, Ellis1 stated that his invention is particularly for the treatment of citrus trees but has to say in this regard, “Ordinarily the soluble compounds of arsenic, especially if used in effective strength for insects, have a defoliating action, but in the present case, by exposure of a solution of, for example. potassium thioarsenate, oxidation and carbonation take place more or less in the case of the polysulfid, thereby throwing out of the solution to a very considerable degree the previously dissolved sulfid of arsenic, and rendering the arsenic comparatively harmless to vegetation. This action is especially marked in the case of the polysulfid of calcium.” 4 , solution was prepared by dissolving precipitated arsenic trisulfid in a lime-sulfur solution of I . 310 specific gravity, together with a little gelatin which seemed to aid in the solution and would serve as an adhesive when the material mas sprayed. The proportion of 2 j grams of arsenic trisulfid to I O O cc. of the lime-sulfur solution to 0 .j gram of gelatin agitated on a shaking machine till reaction m-as complete, gave on filtering a clear, deep yellow solution of I . 3 7 specific gravity. Exposed t o air, this solution decomposed and formed a yellow gel, which, on drying, adhered tenaciously to the surface supporting it. On analysis this solution yielded the results given in the table following. The figures for theoretical solutions of calcium thioarsenite and calcium thioarsenate having 7 . 5 I per cent or‘calcium are given for comparison. From the analyses the solute is seen to approach . the composition of calcium thioarsenate JT-hich salt must be present in large quantity. 1 LOC.
cit.
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
664
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.”
