UNIVERSITY OF CALIFORNIA PUBLICATIONS IN AGRICULTURAL SCIENCES Vol. 4, No. 10, pp. 245-337, 35 text figures March 22, 1922 EQUILIBRIUM STUDIES WITH CERTAIN ACIDS AND MINERALS AND THEIR PROBABLE RELATION TO THE DECOMPOSITION OF MINERALS BY BACTERIA BY DOUGLAS WRIGHT, Jr. CONTENTS PAGE Introduction 245 Object of investigation 249 Method of attack and theory 250 Experimental methods 255 Data 257 Summary 263 INTRODUCTION The importance of the bacterial population to the soil is well recog- nized. The role of micro-organisms in the processes of ammonification, of nitrification, and of nitrogen fixation has been the subject of so much investigation, and has been reviewed so often in the literature that it is generally accepted as fact. The influence of bacterial life, or of the end- products resulting therefrom, causing as it does the solution of necessary plant nutrients from the mineral particles within the soil, has been the object of much speculation, some of which has been substantiated by experiment. Aside from this effect of bacteria upon the mineral particles within the soil, there is some reason for believing that rocks may undergo disintegration and degradation into soil through the action of bacteria. This subject has been discussed and investigated at some length by various writers, whose work will be mentioned later. The formation of the mineral portion of the soil is due to the opera- tion upon the rock mass of three general factors, namely, changes in 246 University of California Publications in Agricultural Sciences [Vol.4 physical environment, chemical action, and biological activity. The first of these exerts so apparent an influence upon rocks that it has long been recognized and subjected to careful investigation by geologists. As applied to soils, these effects belong in the realm of the soil physicist and therefore will not be considered in this paper. The chemical agencies chiefly instrumental in breaking down and dissolving mineral material are water, solutions of varying amounts of NH3 and C02, various salts, organic acids, and organic compounds. The effect of solutions, especially of neutral salts, has been the subject of extensive investigation. This work will be reviewed later in the section of this paper dealing with method of attack and theory. Certain biological activities are generally acknowledged to be op- erative in breaking down the rock mass and preparing it for use as a suitable medium for the growth of plants. Some of these are mechanical, such as the manifest action of roots in prying apart portions of rock. Other effects on rocks are far less easily discernible, due to the slight action of a vast population of microscopic flora found upon rock in all stages of its decomposition. The growth of algae, both alone and in their symbiotic relationships with the lichens, may aid, through the effect of respiration products, in the solution of minerals. It is likely, however, that the more important office of these simple green plants is to serve directly or indirectly as a source of energy for the growth of the still smaller organisms — the bacteria — in situations where the supply of organic materials is limited. A statement concerning the effect of bacteria in rock decomposition was made by Muntz1 as early as the year 1890. He found bacteria "in the denuded rocks of the Alps, the Pyrenees, the Auvergne, and the Vosges comprising the most varied mineralogical types: granites, por- phyries, gneiss, mica schist, volcanic rocks, limestones, and sandstones, . . . Often the action is not confined to the surface, but extends into the depth of the rock mass. This is the case with the so-called rotten rocks of which the particles become disengaged and separate as is often seen in limestones, schists, and granites. ... In decomposed rocks I have always verified the presence of nitrifying organisms." Branner2 takes issue with Muntz's assumptions, citing the" need of bacteria for a large supply of oxygen and nitrogen, and their sapro- phytic habit as prohibitive of their growth to any extent upon or in rocks. J bid Branner's statements been made some years later, they undoubtedly would have been modified by recent information con- cerning the nitrogen compounds of the fundamental rocks. The in- vest igations of IIa.ll and Miller3 show that part of the nitrogen in certain 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 247 clay soils may have been derived from the nitrogen compounds in the rocks from which those soils were formed. Merrill4 mentions bacteria as possible agencies in the decomposition of rocks. Renault5 found bacteria present in coal, and postulates their action in coal beds as that of the transformation of carbonaceous material into methane and hydrogen. Holland6 suggests that the phenomenon of laterization may be due to the action of bacteria, possibly to some specific organism allied to the sulfur and iron bacteria, and gives certain observations which lead to this belief. Lacroix7 makes the following statement: "The bare rocky islet of Cabras, near San Thome in the Gulf of Guinea, is covered with a mantle of slightly ferruginous aluminum phosphate which is sometimes several centimeters thick. This has originated from the interaction of some of the products of bird guano and the underlying rock, aided, doubtless, by microbes." All the conclusions in the literature mentioned thus far are of a conjectural character and are the result of observation only, no con- trolled or investigational work having been presented in support of the opinions offered. The most important systematic investigation of the action of bacteria on rocks was undertaken by K. Bassalik8, and is reported by him in two papers, The Decomposition of Silicates by Soil Bacteria, and The Decomposition of Silicates by Soil Bacteria and Yeasts. The first of these papers is more or less preliminary, the author drawing the conclusion that bacteria are able to derive their necessary mineral nutrients from the feldspars, and that appreciable quantities of unweathered orthoclase are dissolved by bacteria, probably by means of C02 produced by the latter. The second paper reports an elaborate study of the effect of the growth of several organisms upon various minerals. B. extorquens, several of the nitrifying organisms, butyric acid bacteria, and yeasts were tried upon twelve widely varying silicates and upon apatite. A partial summary of Bassalik's results is given here: 1. Bacteria are able by means of their products of respiration to cause a significant solubility of pulverized silicates. 2. Those which produce organic acids, as Clostridium Pasteurianum, influence more strongly the solubility of the silicates. 3. In the action of micro-organisms upon rocks, the intensity of contact of the organism and the mineral to be dissolved is of greater importance than the various agents of solubility. 4. Thus, B. extorquens, which produces only C02, has the strongest solvent effect through its close and firm envelope of the mineral particles. 248 University of California Publications in Agricultural Sciences [Vol. 4 5. Yeasts, which produce much more C02 in cultures than B. extorquens , cause a smaller solubility because of the absence of the close contact with the mineral particles. 6. The nitrite bacteria are also able to effect a significant solubility of silicates as the result of their physiological property of oxidizing NH3, but they affect those minerals rich in alkaline earths much more than those rich in silicates. 7. The significant solubility of apatite seems to be a property only of those bacteria which produce organic acids, for this mineral is dissolved only in moderate degree by those organisms which produce C02. 8. In the filtrates of the bacterial cultures, especially with B. extorquens, can be recovered all the chemical constituents present in the minerals experimented with. Those most easily going into solution are the alkalis, then the alkaline earths and iron, silicic acid much less, and clay the least. This summary presents some interesting conclusions; and a close review of the paper shows that they are the result of careful work. Bassalik, however, does not get at the fundamental causes of the differences in the effects of organisms. This investigator refers, in conclusions 3, 4, and 5, to the closeness of contact of organisms to the mineral as an important factor in determining the magnitude of the action of B. extorquens; but he does not offer plausible proof of this assumption, and it would seem that his conclusion concerning this point may be erroneous. If we have in solution H2C03 from the pro- duction of CO2 by B. extorquens, the concentration of the acid should depend upon the partial pressure of the C02 above the liquid and the rate of C02 production by the organism. The same should be true with the yeast, and as the yeast, according to Bassalik's own state- ment, produces C02 more rapidly than does B. extorquens, and if, as he also states, the solubility is effected by the concentration of C02, the yeast should effect the greater solution of the mineral. This should be true, both in the solution culture and in the solution film surrounding the mineral particles, where the organisms are grown upon the moist mineral. Thus it would seem that any greater effect of B. extorquens should be attributed to some specific action on the mineral, such as oxidation, hydration, etc., rather than to C02. Furthermore, the bac- terial envelope, which is referred to as enclosing the mineral particles, may consist of a gelatinous coating produced from the mineral particle itself, rather than of an aggregate of bacteria (this coating being greater where the action upon the mineral is greater). In 1915 T. Kawamura9 described an organism found in some volcanic material upon one of the mountains of Japan, at an altitude of 6,600 feet. This organism is of special interest as one which has a specific ad ion upon a silicate material. It forms a zoogloeic mass, the ash of which contains an unusually large amount of silica, 8.873 per cent. Kawamura proposed the name Volcanothrix silicophila for the organism. 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 249 A comprehensive discussion of the action of bacteria upon minerals would not be complete without some reference to the action of certain organisms upon the iron, sulfur, and phosphorus compounds found in rocks and soils. However, since it is the purpose of this paper to deal with an entirely different phase of the subject, a brief reference to the bacterial processes affecting these compounds will suffice. Lipman and McLean10 studied the effect of the oxidation of sulfur upon rock phosphate and found appreciable amounts of the phosphate dissolved through the action of the resulting acid. Stoklasa11 found marked solubility of bone meal through the action of soil bacteria and attributed it to the action of enzymes upon the bone meal. Koch and Kroeber12 and later Kroeber13 determined the solubility of different forms of phosphate in the acids produced by the growth of soil and sewage organisms upon dextrose. Kroeber concluded that the acids produced by bacteria and yeasts in the soil may be of great im- portance in rendering phosphate soluble. In cultures where CaC03 was present little or no phosphate was made soluble. Sackett, Patten, and Brown14 in a somewhat similar work found that there was a decided solution of the insoluble phosphate when bacterial growth was accompanied by acid formation. They believed that acid is not the sole solvent. Hopkins and Whiting15 discuss the effect upon rock phosphate of the nitrous acid produced through the oxidation of NH3 by Nitrosomonas. OBJECT OF INVESTIGATION Bacteria may effect the solution and disintegration of minerals in at least two ways: 1. Through the oxidation or reduction of one or more of the con- stituents of the mineral by specific organisms. 2. By the action of some end-product of bacterial activity: i. e., H ion resulting from acid produced, or OH ion from the production of NH3. In the present investigation some of the fundamental considerations in connection with the second phase of the subject were studied, the work being limited to the effect of acid end-products. In none of the work reviewed in the foregoing section have attempts been made to obtain results which may be used to determine whether the action of bacteria upon minerals may follow the usual chemical laws, or at least 250 University of California Publications in Agricultural Sciences [Vol. 4 present some constant relationship which may be expressed in an empirical formula. The work in hand has had for its object the pro- curement and interpretation of data suitable for the confirmation of some such relationship. METHOD OF ATTACK AND THEORY In order to obtain such data it was found necessary to use a different method of attack from that usually pursued in a bacteriological problem. The most common approach to such a problem is by the determination, either in solution culture, in sand culture, or in culture upon the moist pulverized mineral itself, of the amount of material made soluble by the growth of certain organisms. This method gives a series of isolated results, which, though no doubt interesting in themselves, are entirely unrelated either among themselves or to any factor which may control the magnitude of the bacterial effect. In dealing with the phase of the problem studied in this paper, a different method is employed, a method by which it is hoped to show a certain relationship between H ion produced by bacteria and the amounts of bases brought into solution. The magnitude of the effect of bacterial end-products upon a mineral will depend upon the equilibrium involving that end-product and mineral. As stated before, in this study it is elected to deal with cases in which acids are the end-products in question. Therefore, it was deemed necessary first to study the equilibria of certain acids, used over a wide range of concentrations, with certain minerals. The object of these equilibrium studies was to compare the H ion concentrations of the acids, at the various molar concentrations, with the amounts of material which are brought into solution, so to speak, by these H ion concentrations. Later, studies were made of the H ion production by certain organisms, and of the equilibria involving these acids and the minerals, the H ion and the amounts of material in solution being determined. There is an extensive literature dealing with the equilibria of various soils and minerals in contact with solutions of acids, of bases, and of salts. This literature deals largely with the absorption of bases by soils and minerals, and with the exchange of bases between solution and soil or solution and mineral. In nearly every instance, however, the data are insufficient to warrant their use for substitution in formulae. 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 251 The earlier work is so ably and completely reviewed by Sullivan,16 in his consideration of The Interaction between Minerals and Water Solutions, that it seems advisable to refer the reader to that excellent resume rather than to attempt a repetition here. This review covers the work of Thompson,17 Way,18 Eichhorn,19 Henneberg and Stohmann,20 Lemberg,21 Peters,22 Liebig,23 Rautenberg,24 Van Bemmelen,25 Armsby,26 and Boedeker,27 and deals largely with the controversy of the physical process of adsorption versus chemical reaction as the cause of the absorption and exchange of bases in soils. The work of Dittrick28 is not included above. His work is reported in two papers, and covers experiments with a granite and an amphibole paridotite, and solutions of KC1, NaCl, NH4C1, CaCl2, MgCl2, KN03, K2S04, and K2C03, in the concentrations N/1, N/10, and N/100. He found Ca and Mg dissolved by the solutions, the least by N/1 solution, more by the N/10 solution, and most by the N/100 solution. The amount of exchange was greater with the more decomposed rock. Repeated extraction with solutions removed roughly twice as much material as a single extraction. The action of an acid upon a silicate is really an exchange of H ion for any of the bases which come into solution through its action. This exchange is a reversible chemical reaction, and as such should conform with the chemical laws applicable to such reactions. Let us consider a simple case of reversible reaction, or balanced action, that of the union of hydrogen and iodine to form hydriodic acid: H2+I2-2HL In this reaction there is a point of equilibrium which is represented by the equation : Ch2 X C12 _ ki _ „ Chi K This is an example of homogeneous equilibrium, involving the gaseous phase only. A somewhat different case is encountered with the decomposition of calcium carbonate into carbon dioxide and calcium oxide: CaC03 =0= CaO + C02. Here we have both gaseous and solid phases. The amount of gas taking part in the reaction may be measured by its pressure, but the solid must be considered in a different light. This reaction may be considered as taking place in the gaseous phase, the solids present fur- nishing a constant supply of CaC03 and CaO vapor. Then if C is the 252 University of California Publications in Agricultural Sciences [Vol. 4 pressure of CaC03, Ci the pressure of CaO, and c the pressure of C02 at equilibrium, the equation at equilibrium is: kC = kiCiC, or c = r-~r = K Going farther we have the following as a reaction in which we have a solid and a gas on both sides of the equation : H20 + Fe - FeO + H2 Let c be the concentration of H20, C that of Fe, Ci of FeO, and Ci of H2. At equilibrium we then have the equation: kcC = ki Ci Ci. , c ki Ci T^ and — = -j— ft = & Ci kC or — = K Ci Now applying this last equation to a case where we have a solution of a salt acting upon a solid to form another salt in solution and a solid we will take the following reaction: BaS04 + Na2C03 =c= Na2S04 + BaC03. Let C, c, Ci and Ci be the respective concentrations of the reacting substances. Then from the above equation -=K, Cl CNa2CQ3 _ T7- Cn,i2&04 This last equation shows that the equilibrium point is measured by the ratio of concentrations of the soluble reacting materials. As stated by Walker:29 "The active masses of the barium salts may be accounted constant in the reaction, for although they are generally spoken of as ' insoluble ', they are in reality measurably soluble in water. The aqueous liquid in contact with them will be and remain saturated with respect to them, i.e., their concentration and active mass in the solution will be constant. The equilibrium will thus be determined by a certain ratio of the concentrations of the soluble sodium salts, independent of what the actual values of the concentrations may be." A mineral in contact with an acid solution is very similar to the last case cited above, and at any concentration of the acid the equilibrium should be measured by the ratio concentration of the acid concentration of the material in solution when these are measured at equilibrium. = K 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 253 The H ion is usually assumed to be the measure of the active acid. In acid solution the H ion concentration is some function of the molar concentration of the acid. Since gas chain measurements yield values which approach the theoretical H ion concentration, determinations of the H ion concentrations, Ch, by this method may be substituted for " concentration of acid" in the above formula and the ratio ^material in solution will be constant. When dealing with materials as complex in their chemical structure as are minerals, it is recognized that a rigid adherence to the theoretical laws can not be expected, and it becomes necessary, therefore, for a comprehensive knowledge of such reactions as are considered in this paper, to resort to certain empirical formulae. It is obviously imprac- ticable to attempt to consider in the term " concentration of material in solution," as used in the formula above, all the bases which may be present in the solution in contact with the mineral at equilibrium. These considerations lead to the assumption that any one of the bases may be taken as measuring the magnitude of the action of the acid on the mineral. Consequently, it is suggested that the formula thus far developed theoretically, be changed to the empirical formula — h = K Ca ^ where Ch is the concentration of hydrogen ion, and Ca represents the molar concentration of Ca, Mg, Fe, or K in solution at equilibrium with the acid. Since it is desired to study the initial H ion concentration with respect to Ca, Mg, Fe, or K in solution, it becomes necessary to add a still further modification to the empirical formula — namely, the expres- sion of the initial H ion concentration in terms of, or as some function of, the H ion concentration at equilibrium. It is found that this is an exponential function of the H ion concentration at equilibrium. (See fig. 0.) ' In this figure, log. Ch of the acid alone is plotted against log. Ch of acid in contact with the mineral. The resulting graph is a straight line, indicating that the ratio is constant, at least over a certain range of concentrations. Thus Ch of the acid alone is a logarithmic or ex- ponential function of Ch of the acid in contact with the mineral, or C Cx Ch = Ch • Then the equation — = K becomes — = K, where Ch is the 254 University of California Publications in Agricultural Sciences [Vol.4 initial H ion concentration of the acid, Ca the concentration of Ca, Mg, Fe, or K in solution at equilibrium, and K is a constant. This equation is the one used in the consideration of the data contained in this paper. The formation of acid as the end-product of bacterial activity is a property common to many organisms including many which are com- monly found in soils. Acid production by bacteria has been the subject of many investigations. It is used as a means for identifying the various members of the Colon group of bacteria, and consequently the fermentation of sugars by this group has been widely studied. A review of the entire field will not be attempted, but it is well to mention work having a more or less direct bearing upon the subject in hand. Harden30 studied the Chemical Action of B. coli communis and Similar Organisms on Carbohydrates and Allied Compounds. He found that the lactic acid produced never exceeds one-half of the sugar fermented. The amount of acid formed varies with the different sugars. In a later study with Penfold 31 he used B. coli on a medium com- posed of 2 per cent glucose and 1 per cent peptone. He gets of alcohol, acetic acid, formic acid, C02, lactic acid, and succinic acid, respectively 17.22 per cent, 20.60 per cent, 2.55 per cent, 17.30 per cent, 40.60 per cent, and 4.80 per cent of the sugar used. With a selected strain of B. coli, the lactic acid reaches 70 per cent of the amount of sugar used. Michaelis and Marcora32 find that the highest degree of acidity produced by B. coli at 37° C. is 1 x 105. In the lactic acid fermentation of sugars, Claflin33 notes the formation also of formic, propionic, and acetic acids, the acetic acid formation depending upon the degree of aeration. Ninety-five to 97 per cent of the sugar may be converted into lactic acid, with a very low production of volatile acids, not over one-half per cent. He claims that the nature of the acid produced depends upon the organism and not upon the nature of the medium. In the present work it must be shown what is the amount of acid, or rather the H ion concentration, produced by the organisms upon the carbohydrate media used, and what is the effect of this concentration upon the minerals. Is this effect similar to that of the acids alone? 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 255 EXPERIMENTAL METHODS As suggested in the foregoing section, the experimental work is divided into two parts, the first consisting of the equilibrium studies with the minerals and acid solutions, the second of bacteriological studies. Equilibrium studies. — The acids used were hydrochloric, sulfuric, oxalic, phosphoric, lactic, formic, and acetic. It will be observed that these acids vary in the degree of dissociation for any given concentra- tion, hydrochloric acid being the most highly dissociated, and acetic acid being the least ionized. The minerals were calcium silicate, ortho- clase feldspar, biotite, and granite. They were ground in a ball mill to pass a 200-mesh sieve. The acids were used in the concentrations : N/5, N/25, N/50, N/100, N/250, N/500, N/1,000, N/2,000, N/5,000, and N/10,000. The work was carried on at room temperature. The equilibrium studies were arranged in four series, one for each mineral, and each series contained a sub-series for each acid. 200 cubic centimeters of solution were thoroughly shaken with 5 grams of mineral, Jena glass- ware being used. The solutions were allowed to remain in contact with the mineral for three days, which time is shown in the following table to be sufficient for equilibrium. Table Showing the Effect of the Time of Contact upon the H ion Concentration. Orthoclase + N 5 HC1 Days H ion concentration 1 709 xlO-1 2 636X10-1 3 615X10-1 4 656 x 10-1 5 615 x 10-1 As much as possible of the supernatant solution was then pipetted off and filtered through a Whatman No. 42 filter paper, an unfiltered portion being taken, however, for the H ion determination. In an aliquot of the filtered solution, calcium, iron, magnesium, and potassium were determined, the calcium and iron by titration with potassium permanganate, the magnesium and potassium gravimetrically as the pyrophosphate and chloroplatinate respectively. 256 University of California Publications in Agricultural Sciences [Vol. 4 The H ion determinations were made by the use of the hydrogen electrode, with the same modifications as were used by Sharp and Hoagland34 for soils. These determinations are made both on the acid solutions, and on the acids in contact with the minerals. A question arose as to the possibility of the formation of a gelatinous coating upon the surface of the mineral, which would hinder the further action of the acid, and prevent attainment of equilibrium. In order to ascertain whether the amount of shaking had been sufficient to remove this film and allow the reaction to come to equilibrium, the fol- lowing experiment was proposed. A 5-gram portion of mineral was shaken with 200 cc. of N/5 HC1, as in the experimental procedure. The mineral and solution were then poured upon a filter paper, and the mineral was dried and then ground in a mortar. H ion determinations were made upon the filtrate. The filtrate was poured upon the dried mineral and allowed to remain for three days with frequent shaking. H ion determinations were again made. The following data show that there is no significant change in H ion concentration in the second contact of the solution with the mineral : H ion Cone. Calcium silicate +N 5 HCl....lst contact 0.607 x 10"1 Calcium silicate +N 5 HC1....2d contact.. . . 0.607 x 10"1 Labradorite +N 5 HCl....lst contact 0.797 x 10"1 Labradorite +N 5 HC1....2d contact 0.828 x 10"1 Bacteriological work. — Three organisms were used, Azotobacter, Bacillus coli, and B. lactis acidi. The first of these was chosen because of the very high H ion concentration which it produced upon dextrose solution, nearly 1. x 10_1 as determined by Dr. Waynick in this labora- tory. B. coli is referred to in the literature previously cited as producing large amounts of acid, and B. lactis acidi was taken as a typical acid producer. Azotobacter were grown upon 2 per cent dextrose solution, B. coli in a solution of 2 per cent dextrose and 1 per cent peptone as used by Penfold, and B. lactis acidi in 1 per cent dextrose. The work was arranged in three series, one for each organism. Each series con- tained five cultures, each culture containing 1,000 cc. of solution in 1,200 cc. Florence flasks. One culture contained no mineral. The other cultures contained 25 grams of mineral each, one with calcium silicate, one with orthoclase feldspar, another with biotite, and one with granite. These cultures were run for a total time of sixteen days, H ion determina- tions being made at 1, 2, 3, 5, 7, 9, 11, and 16 days, and on each of these days 100 cc. of solution was removed for the determination of calcium, iron, magnesium, and potassium. The cultures were grown at a tem- perature of 28° C. and the customary bacteriological precautions were observed throughout the work. 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 257 DATA The data obtained by the methods given above are reported in tables 1 to 38 inclusive. The amounts of calcium, magnesium, iron, and potassium are calculated and expressed as moles per liter. Both the initial and final H ion concentrations are also reported as gram mole- cules per liter. For the convenience of the reader, the logarithms of these numerical values are given in adjacent columns. Accompanying each table is a graphical representation of the rela- tion between certain series of values given in that table. (Owing to a loss of material during the analysis, tables 3, 9, and 22 are incomplete; there are, therefore, no graphs for these tables.) The logarithms of the H ion concentrations, log. Ch, are plotted along the ordinates, and the logarithms of the concentrations of Ca, Mg, Fe, or k, log. Ca, along the abscissas, and the average curve is drawn through the points thus obtained. In the section of this paper dealing with " Method of Attack and Theory," certain assumptions are made and ultimately expressed in the Cx empirical formula, — = K. By substitution of the experimental data Ca in this formula, the values of the constants x and K may be calculated. If these values of x and K are constant for a given series, then the ratio, — , is constant for that series, and the plotted graph representing that Ca ratio will be a straight line, or conversely, a straight line curve indicates that x and K are constant. The straight line graph expresses a direct ratio between series of values, these values being, in this case, the logarithms of Ch and of Ca. The exponential constant x and the reasons for its use have been discussed previously. It expresses the relation of H ion at equilibrium to the initial H ion concentration of the acid. That this relationship is of an exponential character may be due to chemical reaction, to ad- sorption, or to a combination of these phenomena. It is not proposed, however, to differentiate here between adsorption and chemical re- action, the purpose of this work being to provide a means, empirical if necessary, of accounting for the magnitude of the action of acids upon minerals. The constant K is the numerical expression of the ratio of the logarithm of the initial H ion concentration to the logarithm of Ca, Mg, 258 University of California Publications in Agricultural Sciences [Vol. 4 Fe, of K brought into solution, so to speak, by that H ion concentration. The numerical magnitude of K for any table represents the slope or inclination of the graph plotted from that table. The range of values for K may be very large, varying from infinity, for a horizontal line, to zero, for a vertical line. Since it is possible to draw a straight line averaging the points plotted from the experimental data, the graphical method is employed for obtaining values of log. Ch and log. Ca for substitution in the equation for the calculation of x and K. By this means average values of x and K may be computed without resorting to a calculation of all the possible combinations of equations for which data are available. The use of this procedure eliminates a large part of the tedious mathematical routine, and it is recognized as yielding averages sufficiently close to the statis- tical average to serve the purpose contemplated in this paper. If the above preliminary remarks are borne carefully in mind, the following consideration of the groups of tables and graphs will be clear. Tables 1 to 7 contain the data for the equilibria between calcium silicate and the acids. The figures accompanying these tables are sufficient to show that the graph for any given series is a straight line. As stated before, this signifies that x and K are constant for each series, and that the reaction of the acid with the mineral takes place in accord- ance with the formula — = K. The slope of the graphs, however, seems Ca to become less for the equilibria involving the less dissociated acids, the slope for acetic acid being much less than that for hydrochloric acid. As explained before, this difference in slope is indicated by the following numerical values for the constant K calculated from the graphs, the slope becoming less as K increases : HC1 K = 0.01391 Sulfuric acid K = 0.2642 Phosphoric acid K = 0.4448 Lactic acid K = 14.86 Formic acid K = 335.5 Acetic acid K = 941.2 Since, as stated before, the graphs represent ratios of log. Ch to log. Ca, and since this ratio varies with the slope of the graph, it would seem, from a comparison of the curves for HC1 and acetic acid, that an acid such as HC1, which is highly ionized, brings smaller amounts of materia] into solution per unit increase of H ion than do those acids, acetic for instance, which have a lower ionization constant. This apparent difference in the action of various acids is due undoubtedly to 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 259 the fact that the commercial calcium silicate was used for this work, and that it contained considerable quantities of CaC03, as shown by the marked effervescence which occurred when the acid was added to this material. The loss of C02 from the system undoubtedly affected the true equilibrium, and this apparently greater action of the less dissociated acids is the result. As will be seen in the considerations which follow, this difference in effect between various acids occurs only with calcium silicate. In tables 1 to 7, as well as in those which follow, there are no data for calcium where oxalic acid is used, because of the insolubility of the resulting calcium oxalate. This fact is mentioned again, and its importance is emphasized further, in connection with a general state- ment corcerning the action of the H ion concentration of acids upon minerals. The data for the various acids and orthoclase are found in tables 8 to 12 inclusive. From a comparison of the corresponding graphs, it is seen that they are quite steep, and that all have approxi- mately the same slope. This observation is verified by a consideration of the constant, K, as calculated for the various members of this group of tables. The fact that K is very small is evidence that the graphs approach the perpendicular, and when it is remembered that the values for K range from zero to infinity for a change of 90 degrees in slope, it is obvious that the very small range of values for K given here, 0.00002661 to 0.000001427, represents a very small difference in the slopes of the various curves. The fact that K is constant for each series, and that the corresponding graph is a straight line, goes to show that the calcium coming into solution is a logarithmic function of the initial H ion concentration of the acid, and that the assumptions ex- Cx pressed in the formula — = K are verified by experimental evidence . Further proof of these assumptions is offered in the next group of tables, numbers 13 to 19 inclusive, which give the data for the acids in equilibrium with biotite. Data for calcium, magnesium, and potassium in solution are reported. As in the previous series of tables, the graphs for calcium are straight lines and have about the same slope, the extreme range of values for K being from 0.00005790 to 0.000001071. The constant K for the magnesium determinations is more variable, but still no large discrepancy is apparent, the values ranging from 0.04373 to 0.000008395. A deviation from the straight line graph is encountered in the figures and tables expressing the equilibria for granite and the acids, 260 University of California Publications in Agricultural Sciences [Vol. 4 tables 20 to 26 inclusive. When the logarithms of the data for iron are plotted against the logarithms for H ion concentrations and the lines are drawn through the points thus obtained, the resulting curves are not straight lines. (See figures 20 to 26.) The flatter portion of the curve occurs in every instance at approximately the value, 3.0, repre- sented by that logarithm of the H ion concentration, and probably is due to the formation of another compound of iron at that concentra- tion. Since these curves are not straight lines, it is obvious that no constant values for x and K may be calculated therefrom, and further- more it may be inferred that any iron compounds in the mineral do not react with the acids in accordance with the proposed formula. The curves for calcium, however, are straight lines, thus affording still further proof that the assumptions regarding the nature of such re- actions are correct as far as calcium is concerned. The graphs have nearly the same slope throughout the series of figures, the values for K ranging from 0.000001328 to 0.000007799. In a general survey of the graphs thus far discussed, instances may be observed in which certain plotted points are far from coincident with the straight line graph. In certain cases, these discrepancies represent error in the determinations. Where they appear in the lower portion of the graph, however, the last two -or three points dropping below the curve, they occur because the lower limit of the determination has been reached, and no smaller amounts can be determined with any degree of accuracy. A consideration of the meaning and the possible relationships of the results thus far reviewed is not inappropriate at this point. It is the opinion of the writer that that type of investigation is the most valuable which has for its object the procurement of data which are related, either among themselves, or to certain controllable factors, and which may be taken as the basis for, or in verification of, some general law suitable either for the explanation of certain phenomena or for direct application in the prediction of future results. Thus a general con- sideration of the tables and figures leads to the following remarks. All the straight line graphs for a given mineral, excepting calcium silicate, the deviation of which has been explained, have practically the same slope and give nearly the same values for x and K. It follows therefore, that if the curves for one mineral in contact with the various acids be superimposed one upon the other, they will all fall practically in the same straight line. This would seem to indicate, for a given mineral, and within the limits of the concentrations used, that the amount of calcium, magnesium, or potassium coming into solution is a function 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 261 of the H ion concentration of the acid, regardless of the nature of the acid used, except, and this exception is extremely important, in those cases where the acid forms compounds which are less soluble at any given H ion concentration than the compounds in the mineral itself. The importance of this exception must be emphasized, and it is illus- trated in a very striking manner by the different series with oxalic acid where only traces of calcium are found in solution. It is recognized that this illustration represents an extreme case and that other so- called insoluble compounds may approach the mineral compounds in solubility. The objection was raised to the foregoing generalization that a N/100 solution of acetic acid, for instance, contains the same total molar concentration of hydrogen as a N/100 hydrochloric acid solution, regardless of the relative H ion concentration of these acids. The hydro- chloric acid is, of course, the more highly dissociated acid, but will not the slightly dissociated acetic acid continue to give off H ion as that already in solution combines with the mineral, and should not the ulti- mate result be the same with the acetic as with the hydrochloric acid for a given molar concentration? That this objection is not sub- stantiated by fact is due doubtless to the following reason. In general the salts of acetic acid are much more highly dissociated than is the acid itself. Consequently, the acetates formed by the contact of acetic acid with the mineral will be fairly highly dissociated, thus supplying the solution at equilibrium with a certain concentration of acetic ion. The presence of this acetate ion will depress or prevent the further ionization of the acetic acid in solution, and thus practically limit the action of the acetic acid to its original H ion concentration. This same explanation will hold for other slightly dissociated acids. The general relation existing between the H ion concentration of acids and the amounts of Ca, of Mg, or of K in solution, may have the following practical application. It is desired to determine the effect of certain acids upon a mineral. This mineral may be studied in equi- librium with different concentrations of HC1, and the logarithmic graph constructed as in the foregoing mineral series. Any point on this graph represents a ratio of log. H ion to log. Ca, or whatever base it is desired to consider, in solution. Thus, by determining the H ion con- centration of the acid whose action it is desired to predict, we may, by referring to the graph, estimate the magnitude of the effect of the acid upon the mineral, at least within certain limits already discussed. The application suggested above may be made to the effect of acids produced by bacterial growth, and in the prediction of their action upon a given mineral. 262 University of California Publications in Agricultural Sciences [Vol. 4 The above application is suggested merely as a possibility, and it is fully recognized that there is room for much further study and research before the existence of such a general relationship can be definitely established. It must be emphasized also that the constants for one mineral and one set of conditions can not be applied directly to another mineral and a different set of conditions. The constants must be de- termined, and the resulting graph constructed for every application of the relation suggested. The data obtained from the bacterial series still await consideration. As expressed in tables 26 to 38, and in the corresponding figures, the action of the acids produced by bacteria seems to differ in magnitude from the action of the acids used in the foregoing series. In regard to this difference, it should be observed that Ch, the H ion concentration, was determined, for the bacterial series, in solution cultures with no mineral present. Had the bacterial growth been stopped immediately following the H ion determination, and had this solution then been brought into contact with the mineral, the magnitude of the effect should have been comparable with that of the acid series. Instead, the amounts of material coming into solution were determined in a series parallel with the above, wherein bacteria were grown in solution in contact with the minerals. It had been assumed that the rate of H ion production would be the same, both in solution culture and in solution in contact with the mineral. This assumption was found to be incorrect. In the mineral cultures the acid was partly neutralized as produced, and the growth of the organism was not inhibited by the increasing concentration of acid as it was in the dextrose solution with no mineral. Consequently, the total H ion as produced in the mineral cultures, and indicated by the large relative amounts of material coming into solution in these cultures, was much greater than that produced in the parallel series without mineral. Since the data for H ion, Ch, as expressed in the tables, were obtained from the latter series, it is obvious that the graphs plotted from a ratio of H ion, as determined in dextrose solution, to material in solution, as determined in the mineral cultures, are not directly comparable with the graphs for the equilibria between acids and minerals. The lack of agreement between the acid series and the bacterial series is made evident by a review of the curves and the corresponding constants for the bacterial series. The graphs are straight lines, but they have less slope than do those graphs for the corresponding mineral in equilibrium with the acids. For instance, the constant, K, for ortho- clase and Azotobacter is 19.77 against a value approaching l(h6 for 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 263 orthoclase and the acids, and the graph for the former has much less slope than the graph for the latter. The constant, K, for orthoclase and B. coli is 13,490, against 1CH5 for orthoclase and the acids. B. lactis acidi, which produced acid very slowly, is represented by graphs which more nearly resemble those of the acid-mineral series, and the value for K for calcium from orthoclase, for instance, is 0.0006652. Since dis- crepancies of the same general nature and magnitude as those just pointed out, are apparent in the other graphs and constants for the bacterial-mineral series, the reader is referred to the graphs and tables for further comparisons. The important point brought out by the bacterial series is that the graphs for calcium, for magnesium, and for potassium are straight lines, and that x and K are constant for a given series. Thus it is shown that the reactions between minerals and the acids produced by bacterial growth, conform with the given empirical formula. Since this same formula has been successfully applied to the chemical equilibria between various acid solutions and the same minerals, it may be concluded that the action of bacterial end-products upon minerals, at least when these end-products are acids, is explainable upon the basis that it is a chemical reaction. SUMMARY Equilibria of certain minerals and various concentrations of acids are studied. Equilibria of the same minerals with solutions in which bacteria are producing acid are also studied. The data obtained from the acid-mineral series are applied to the Cx formula — = K. Ca It is found that the reactions occurring in the mineral-acid equilibria conform with the given formula. It is suggested that a general -relation exists between the initial H ion concentration of the acid and the amount of material which the acid brings into solution when in contact with a mineral. A practical application of the relation just referred to, is suggested. The data obtained from the bacterial studies are applied to the formula — = K. Ca The reactions occurring in the bacterial series also conform with the above formula. 264 University of California Publications in Agricultural Sciences [Vol. 4 It is concluded that the action of acid bacterial end-products upon minerals is explainable as a chemical reaction. The author wishes to express his gratitude to Dr. C. B. Lipman for the suggestion of the problem and for his interest and help during the progress of the work, and to Professor L. T. Sharp and Dr. D. D. Way nick for many helpful suggestions. Transmitted September 2, 1919. LITERATURE CITED 1 Muntz, A. 1890. Chimie agricole. Sur la decomposition des roches et la formation de la terre arable. Compt. Rend. Acad, des Sciences, Paris, vol, 110, pp. 1370-1372. 2 Branner, J. C. 1897. Bacteria and the decomposition of rocks. Am. Jour, of Sci., vol. 153, p. 438. 3 Hall, A. D., and Miller, N. H. J. 1908. The nitrogen compounds of the fundamental rocks. Jour, of Agric Sci., vol. 2, pp. 343-345. 4 Merrill, G. P. 1895. Disintegration of the granite rocks of the District of Columbia. Bull. Geol. Soc. Am., vol. 6, pp. 321-332. 5 Renault, B. 1896. Conclusions from an article by Renault entitled, "Les bacteries et leur oeuvre geologique." Nature, vol. 55, p. 40. 6 Holland, T. H. 1903. On the constitution, origin and dehydration of laterite. Geol. Mag., vol. 40, pp. 59-69. 7 Lacroix, A. 1906. Sur la transformation de roches volcaniques en phosphate d'alumine sous 1'innuence de produits d'origine physiologique. Compt. Rend., Acad, des Sciences, Paris, vol. 143, pp. 661-664. 8 Bassalik, K. 1913a. Decomposition of silicates by soil bacteria. Zeitsch. Garungsphysiol., vol. 2, pp. 1-32. 19136. Silicate decomposition by soil bacteria and yeasts. Ibid., vol. 3, pp. 15-42. 9 Kawamura, T. Studies on "Tengunomugimethi." 10 Lipman, J. G., and McLean, H. C. 1916. The oxidation of sulphur in soils as a means of increasing the availability of mineral phosphates. Soil Science, vol. 1, pp. 533-539. 11 Stoklasa, J. 1900. Ueber den Einfluss der Baktcrien auf die Knochenzersetzung. Central- blatt fur Bakt., Abt. 2, Bd. 6, pp. 554-560. 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 265 12 Koch, A., and Kroeber, E. 1906. Der Einfluss der Bodenbakterien auf das Loslichwerden der Phos- phorsaure aus verschiedenen Phosphaten. Fiihling's Landwirt. Zeit., vol. 55, pp. 225-235. 13 Kroeber, E. 1909. Ueber das Loslichwerden der Phosphorsaure aus wasserunloslichen Verbindungen unter der Einwerkung von Bakterien und Hefen. Jour, fur Landwirt., vol. 57, pp. 5-80. 14 Sackett, W. G., Patten, A. J., and Brown, C. W. 1908. The solvent action of soil bacteria upon the insoluble phosphates of raw bone meal and natural raw rock phosphate. Michigan Agric. Exper. Station, Special Bull., No. 43, pp. 363-390. 15 Hopkins, C. G., and Whiting, A. L. 1916. Soil bacteria and phosphates. Illinois Exper. Station Bull. No. 190, pp. 395-406. 16 Sullivan, E. C. 1907. The interaction between minerals and water solutions with special reference to geologic phenomena. U. S. Geol. Surv., Bull. 312, pp. 9-64. 17 Thompson, H. S. 1850. On the absorbent power of soils. Jour. Roy. Agric. Soc, vol. 2, pp. 68-74. 18 Way, J. T. 1850. On the power of soils to absorb manure. Jour. Roy. Agric. Soc, vol. 2, pp. 313-379. 1852. Idem, Second paper, ibid., vol. 13, pp. 123-143. 1854. On the influence of lime on the absorptive properties of soils. Jour. Roy. Agric. Soc, vol. 15, pp. 491-514. 19 Eichorn, H. 1858. Ueber die Einwirkung verdunnter Salzlosungen auf Silicate. Pogg. Ann., vol. 105, pp. 126-133. 20 Henneberg, J. W. J., and Stohmann, F. K. A. 1859. Ueber das Verhalten der Ackererde gegen Losungen von Ammoniak und Ammoniaksalzen. Jour, fur Landwirt. Gottingen, Bd. 7, (Neue Folge, Bd. 3), pp. 25-47. 1858. Ueber das Verhalten der Ackerkrume gegen Ammoniak und Ammoniak- salze. Liebig's Annalen, vol. 107, pp. 152-174. 21 Lemberg, H. J. VON. 1870. Ueber einige Umwandlungen finnlandischer Feldspathe. Zeitschr. der deutsch. geol. Gesell., vol. 22, pp. 335-372. 22 Peters, E. 1860. Studien ueber den Boden aus dem Laboratorium zu Tharand. Landw. Versstat., vol. 2, pp. 113-116. 23 LlEBIG, J. VON. 1858. Ueber einige Eigenschaften der Ackerkrume. Ann. chem., vol. 105, pp. 109-144. 24 Rautenberg, F. VON. 1862. Ueber die Absorptionsfahigkeit verschiedener Bodenarten und das geognostitischen Vorkommen derselben. Jour, fur Landwirt., vol. 10, pp. 49-66. 266 University of California Publications in Agricultural Sciences [Vol. 4 25 Van Bemmelen, J. M. 1899. Die Absorption IV. Die Isotherme des kolloidalen Eisenoxyds bei 15°. Zeitschrift flir anorg. Chemie, vol. 20, pp. 185-211. 1878. Das Absorptionsvermogen der Ackererde. Landwirt. Versstat., vol. 21, pp. 135-191. 1881. Die Verbindungen einiger fester Dioxydhydrate mit Sauren, Salzen und Alkalien. Jour, fur prakt. chemie, Ser. 5, Bd. 131-132, pp. 324- 349, 379-395. 26 Armsby, H. P. 1878. Ueber das Absorptionsvermogen des Bodens fur Basen. Landwirt. Versstat., vol. 21, pp. 397-405. 27 BOEDEKER, C. VON. 1859. Ueber das Verhaltniss zwischen Masse und Wirkung beim Contact ammoniakalischer Fliissigkeiten mit Ackererde und mit kohlen- saurem Kalk. Jour, fur Landwirt., vol. 7, pp. 48. 28 DlTTRICK, M. VON. 1901. Chemisch-geologische Untersuchungen ueber "Absorptionserscheinun- gen" bei zersetzten Gesteinen. Mitt, grossh. bad. geol. Landesan- stalt, vol. 4, pp. 341-366. 1905. Idem, Second paper, ibid., vol. 5, pp. 1-23. 29 Walker, James. 1913. Introduction to physical chemistry. Macmillan. 30 Harden, A. 1901. The chemical action of Bacillus coli communis and similar organisms on carbohydrates and allied compounds. Jour. Chem. Soc. London, vol. 79, pp. 691-698. 31 Harden, A., and Penfold, W. J. 1912. The chemical action on glucose of a variety of Bacillus coli communis (Escherich) obtained by a culture in presence of chloracetate. Proc. Roy. Soc. London, vol. 85 B, pp. 415-417. 32 Michaelis, L., and Marcora, F. 1912. Die Saureproduktivitat des bacterium coli. Zeitschrift Immunitats- forschung u. exper. Terapie, Bd. 14, pp. 170-173. 33 Claflin, A. A. 1912. Products of the lactic fermentation of sugars. Orig. Comm. 8th Intern. Congress Appl. Chem., vol. 25, Appendix, pp. 343-345. 34 Sharp, L. T., and Hoagland, D. R. 1916. Acidity and absorption in soils as measured by the hydrogen electrode. Jour. Agric. Research, vol. 7, pp. 123-143. 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 267 NOTE The following legend refers to all the figures: + = Curve for Calcium. O = Curve for Magnesium. 0 = Curve for Potassium or Iron. The numbers along the ordinates represent the logarithms of the H ion concentrations, or log. Ch. Those along the abscissas measure the logarithms of the concentrations, or log. Ca, of calcium, magnesium, iron, or potassium. 2.0 3.0 4.0 _ 5.0 7.0 6.0 5.0 4.0 3.0 2.0 Fig. 0. (See Table 8) Relation of log. H ion, HC1, to log. H ion, HC1 + Orthoelase. 268 University of California Publications in Agricultural Sciences [Vol. 4 TABLE I Hydrochloric Acid and Calcium Silicate Concentration HC1 Ch, H ion Hydrochloric Acid Log. H ion Hydrochloric Acid H ion _ Ca, Calcium Hydrochloric Acid Mols. per +Calcium Silicate Liter Log. Calcium Mols. per Liter N5 0.0882 2.94547 0.0313 0.00306 3.485721 N25 0.0218 2.33846 0.00000534 0.00218 3.338456 N50 0.0135 2.13003 0.00000175 0.00121 3.02785 N 100 0.00685 3.83569 0.000000671 0.000685 4.835691 N250 0.00321 3.50651 0.000000131 0.000376 4.575188 N500 0.00114 3.05690 0.0000000842 0.000240 4.380211 N 1,000 0.000677 4.83059 0.0000000587 0.000159 4.201397 N 2,000 0.000281 4.44871 0.0000000965 0.000122 4.086360 N 5,000 0.0000326 5.51322 0.0000000719 0.000120 4.079181 N 10,000 0.0000192 5.28330 0.000000620 0.000117 4.068168 Constants for the equation — = K : Ca x = 0.636 K = 0.01391 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 269 2.0 3.0 4.0 5.0 6.0 5.0 4.0 3.0 2.0 Fig. 1. Hydrochloric Acid and Calcium Silicate. (See Table 1) 270 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 2 Sulfuric Acid and Calcium Silicate Concentration Ch, H ion Sulfuric Acid Log. H ion Sulfuric Acid Hion Sulfuric Acid +Calcium Silicate Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter N5 0.0567 2.75358 0.0300 0.00188 3.274158 N25 0.0186 2.26951 0.00000579 0.00197 3.294466 N50 0.0130 2.11394 0.000000450 0.00115 3.060698 N100 0.00632 3.80072 0.000000203 0.000655 4.816241 N250 0.00296 3.47129 0.0000000810 0.000356 4.551450 N500 0.00162 3.20952 0.0000000719 0.000218 4.338456 N 1,000 0.000931 4.96895 0.000000180 0.000148 4.170262 N 2,000 0.000600 4.77815 0.0000000323 0.000099 5.995635 N 5,000 0.000259 4.41330 0.0000000235 0.000079 5.897627 N 10,000 0.000174 4.24055 0.0000000364 0.000089 5.949390 Constants for the equation K: By graphical average : x = 0.799 K = 0.2642 By calculation: x = 0.858 ± 0.0074 K = 0.7332 ± 0.0313 v. = 5.99% v. = 29.05% 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 271 2.0 3.0 4.0 5.0 6.0 5.0 4.0 3.0 Figure 2. Sulfuric Acid and Calcium Silicate. (See Table 2) 2.0 >72 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 3 Oxalic Acid and Calcium Silicate Concentration Ch, H ion Log. H ion Oxalic Oxalic Acid Acid H ion Ca, Calcium Oxalic Acid Mols. per +Calcium Silicate Liter Log. Calcium Mols. per Liter N5 0.0218 2.33846 0.0347 N25 0.0110 2.04139 0.0000192 N50 0.00561 3.74896 0.00000175 N 100 0.00347 3.54033 0.000000433 N250 0.00169 3.22789 0.0000000941 N500 0.00105 3.02119 0.0000000778 N 1,000 0.000554 4.74351 0.0000000719 N 2,000 0.000317 4.50106 0.0000000637 N 5,000 0.000132 4.12057 0.0000000544 N 10,000 0.0000785 5.89487 0.000000469 TABLE 4 Phosphoric Acid and Calcium Silicate Concentration Ch, H ion Phosphoric Acid Log. H ion Phosphoric Acid H ion Ca, Calcium Phosphoric Acid Mols. per +Calcium Silicate Liter Log. Calcium Mols. per Liter N5 0.0125 2.09691 0.0498 0.00307 3.487138 N25 0.00632 3.80072 0.00000707 0.000872 4.940516 N50 0.00424 3.62737 0.00000294 0.000525 4.720159 N100 0.00273 3.43616 0.00000054 0.000366 4.563418 N250 0.00144 3.15836 0.000000268 0.000208 4.318063 N500 0.000762 4.88195 0.0000000941 0.000149 4.173186 N 1,000 0.000372 4.57054 0.0000000482 0.000109 4.037426 N 2,000 0.000213 4.32838 0.0000000350 0.000089 5.949390 N 5,000 0.0000642 5.80754 0.0000000235 0.000074 5.869232 N 10,000 0.0000431 5.63448 0.0000000395 0.000074 5.869232 Constants for the equation — — = K: Ca x = 0.835 K = 0.4448 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 273 2.0 3.0 4.0 5.0 6.0 5.0 4.0 3.0 2.0 Figure 4. Phosphoric Acid and Calcium Silicate. (See Table 4) 274 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 5 Lactic Acid and Calcium Silicate Concentration N5 N25 N50 N 100 N250 N500 N 1,000 N 2,000 N 5,000 N 10,000 Ch, H ion Lactic Acid 0.00561 0.00252 0.00169 0.00114 0.000677 0.000472 0.000270 0.000189 0.000112 0.0000547 Log. H ion Lactic Acid 3.74896 3.40140 3.22789 3.05690 4.83059 4.67394 4.43136 4.27646 4.04922 5.73799 H ion Lactic Acid +Calcium Silicate 0.00577 0.000130 0.00000108 0.000000572 0.000000141 0.0000000877 0.0000000719 0.0000000364 0.0000000395 0.000000126 H Constants for the equation — - By graphical average: x = 1.144 K = 14.86 Constants by calculation x = 1.118 ± 0.0368 K = 12.09 ± 0.326 K: Ca, Calcium Mols. per Liter 0.00308 0.00201 0.00123 0.000812 0.000445 0.000208 0.000148 0.000099 0.000079 0.000074 Log. Calcium Mols. per Liter 3.488551 3.303196 3.089905 4.909556 4.648360 4.318063 4.170262 5.995635 5.897627 5.869232 C. v. = 25.9% C. v. = 12.01% 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 275 2.0 3.0 4.0 5.0 5.0 4.0 3.0 • Figure 5. Lactic Acid and Calcium Silicate. (See Table 5) 2.0 276 University of California Publications in Agricultural Sciences [Vol. TABLE 6 Formic Acid and Calcium Silicate Concentration Ch, H ion Formic Acid Log. H ion Formic Acid H ion Formic Acid +Calcium Silicate Ca. Calcium Mols. per Liter Log. Calcium Mols. per Liter N5 0.00518 3.71433 0.00577 N25 0.00233 3.36736 0.0000635 N50 0.00156 3.19312 0.000000620 0.00119 3.075547 N 100 0.0010 3.00000 0.000000327 0.000694 4.841359 N250 0.000762 4.88195 0.0000000719 0.000365 4.563481 N500 0.000472 4.67394 0.0000000522 0.000208 4.318063 N 1,000 0.000343 4.53529 0.0000000350 0.000138 4.139879 N 2,000 0.000181 4.25768 0.0000000276 0.000119 4.075547 N 5,000 0.0000753 5.87679 0.0000000245 0.000099 5.995635 N 10,000 0.0000398 5.59988 0.0000000719 0.0000248 5.394452 Constants for the equation C K: x = 1.324 K = 335.5 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 277 2.0 3.0 4.0 5.0 5.0 4.0 3.0 Figure 6. Formic Acid and Calcium Silicate. (See Table 6) 2.0 278 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 7 Acetic Acid and Calcium Silicate Concentration Ch, H ion Acetic Acid Log. H ion Acetic Acid H ion Acetic Acid +Calcium Silicate Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter N5 0.00224 3.35025 0.000547 0.00285 3.454845 N25 0.000860 4.93450 0.00000797 0.00250 3.397940 N50 0.000677 4.83059 0.00000100 0.00126 3.100371 N 100 0.000454 4.65706 0.000000279 0.000742 4.870404 N250 0.000387 4.58771 0.000000116 0.000347 4.540329 N500 0.000213 4.32838 0.0000000350 0.000178 4.250420 N 1,000 0.000189 4.27646 0.0000000395 0.0000892 5.950365 N 2,000 0.000104 4.01703 0.0000000350 0.0000694 5.841359 N 5,000 0.0000884 5.94645 0.000000116 0.0000694 5.841359 N 10,000 0.0000414 5.61700 0.000000238 0.0000495 5.694605 Constants for the equation Ca x = 1.465 K = 941.2 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 279 2.0 3.0 4.0 5.0 5.0 4.0 3.0 Figure 7. Acetic Acid and Calcium Silicate. (See Table 7) 2.0 280 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 8 Hydrochloric Acid and Orthoclase Concentration Ch, H ion Hydrochloric Acid Log. H ion Hydrochloric Acid H ion Hydrochloric Acid +Orthoclase Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter N5 0.0882 2.94547 0.0615 0.00159 3.201397 N25 0.0218 2.33846 0.0218 0.001449 3.159567 N50 0 0135 2.13003 0.00836 0.001045 3.019116 N100 0.00685 3.83569 0.00296 0.00094 4.973128 N250 0.00321 3.50651 0.000554 0.000685 4.835691 N500 0.00114 3.05690 0.0000784 0.000565 4.752048 N 1,000 0.000677 4.83059 0.000000935 0.00056 4.748188 N 2,000 . 0.000281 4.44871 0.00000110 0.00040 4.602060 N 5,000 0.0000326 5.51322 0.000000261 0.00038 4.579784 N 10,000 0.00000192 6.28330 Constants for Calcium: 0.00000010 0.000336 4.526339 x = 0.225 K = 0.000006310 1922] Wright: Equilibrium Studies With Certain Acids -and Minerals 281 2.0 3.0 4.0 5.0 6.0 5.0 4.0 3.0 2.0 Figure 8. Hydrochloric Acid and Orthoclase. (See Table 8) 282 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 9 Oxalic Acid AND ORTHOCLASE Concentration Ch, H ion Oxalic Acid Log. H ion Oxalic Acid H ion Oxalic Acid +Orthoclase Ca, Calcium Mols. per Liter. Log. Calcium Mols. per Liter N5 0.0218 2.33846 0.0245 N25 0.0110 2.04139 0.00905 N50 0.00561 3.74896 0.00376 N100 0.00347 3.54033 0.000650 N250 0.00169 3.22789 0.00000564 N500 0.00105 3.02119 0.000000735 N 1,000 0.000554 4.74351 0.000000438 N 2,000 0.000317 4.56937 0.000000294 N 5,000 0.000132 4.12057 0.00000294 N 10,000 0.0000785 5.89487 0.00000294 TABLE 10 Lactic Acid AND ORTHOCLASE Concentration Ch, H ion Lactic Acid Log. H ion Lactic Acid H ion Lactic Acid +Orthoclase Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter N5 0.00561 3.74896 0.00441 0.001190 3.075547 N25 0.00252 3.40140 0.00123 0.00094 4.973128 N50 0.00169 3.22789 0.000650 0.00077 4.886491 N100 0.00114 3.05690 0.000372 0.000495 4.694605 N250 0.000677 4.83059 0.000181 0.00073 4.863323 N500 0.000472 4.67394 0.0000414 0.000495 4.694605 N 1,000 0.000270 4.43136 0.00000322 0.000465 4.667453 N 2,000 0.000189 4.27646 0.00000217 0.000475 4.676694 N 5,000 0.000110 4.04139 0.000000282 0.000366 4.563481 N 10,000 0.0000547 5.73799 0.000000261 0.000238 4.376577 Constants for Calcium : x = 0.324 K = 0.00002661 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 283 2.0 3.0 4.0 5.0 5.0 4.0 3.0 Figure 10. Lactic Acid and Orthoclase. (See Table 10) 2.0 284 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 11 Formic Acid AND ORTHOCLASE Concentrator Ch, H ion Formic l Acid Log. H ion Formic Acid Hion Formic Acid +Orthoclase Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter N5 0.00518 3.71433 0.00296 0.000862 4.935507 N25 0.00233 3.36736 0.000677 0.000812 4.909556 N50 0.00156 3.19312 0.000270 0.000723 4.859138 N100 0.0010 3.00000 0.0000957 0.000713 4.853090 N250 0.000762 4.88195 0.0000153 0.000605 4.781755 N500 0.000472 4.67394 0.00000579 0.000535 4.728354 N 1,000 0.000343 4.53529 0.000000197 0.000535 4.728354 N 2,000 0.000181 4.25768 0.000000197 0.000495 4.694605 N 5,000 0 0000753 5.87679 0.000000205 0.000475 4.676694 N 10,000 0.0000398 5.59988 0.0000000923 0.000426 4.629410 Constants for Calcium: x = 0.142 K = 0.000001427 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 28i. 2.0 3.0 4.0 5.0 5.0 4.0 3.0 Figure 11. Formic Acid and Orthoclase. (See Table 11) 2.0 286 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 12 Acetic Acid AND ORTHOCLASE. Concentration Ch, H ion Acetic Acid Log. H ion Acetic Acid H ion Acetic Acid +Orthoclase Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter N5 0.00224 3.35025 0.000472 0.000074 4.869232 N25 0.000860 4.93450 0.000132 0.000058 4.763428 N50 0.000677 4.83059 0.0000696 0.00062 4.792392 N100 0.000454 4.65706 0.0000431 0.00065 4.812913 N250 0.000387 4.58771 0.0000179 0.00051 4.707570 N500 0.000213 4.32838 0.00000745 0.00048 4.681241 N 1,000 0.000189 4.27646 0.00000225 0.00043 4.633468 N 2,000 0.000104 4 01703 0.000000627 0.00039 4.591065 N 5,000 0.0000884 5.94645 0.000000438 0.00033 4.518514 N 10,000 0.0000414 5.61700 0.000000261 0.00029 4.462398 Constants for Calcium : x = 0.235 K = 0.000006966 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 287 2.0 3.0 4.0 5.0 5.0 4.0 3.0 Figure 12. Acetic Acid and Orthoclase. (See Table 12) 2.0 288 University of California Publications in Agricultural Sciences [Vol. 4 * 53 NM^NCD^^OJHOO Oft lOCOb-i-HCNt^iaOOOCO Pi . coo^ojc^ocoH^g .,2 fc OONMCOCCiOOOCOM^ Mo^S OlHcOOHNiMOOtD'* °^j_3 HOttOOOONNiO'O'O ICO ICO W |Tf |tJh |t}^ 1^ |Tf 1^ W a> «3 COi-HOOb-lOCOCO^ +? " lOOoONOioiocowo: P^-2 &0000000000 5^.tJ O O O O O p p O O O O^i-5 o o o o o o o o o o .3 -.£ OKNHOC^iO^COOJH riS^ OlOCOtDOOOiCOH^N . 3h-! iO"OON05h^03Ht(( ^ a p, Ico Ico Ico Ico |«tf W |tjh 1^ I** W »H CO M^ 55 b-tNr-HOOcO^i-HCOOO • 5 =5 13 ^(Moqi-noooooo w ^.S1-1 oooooooooo Eh eSSRSrt OOOOOOOOOO m Oca d dodo" do' odd g r?2S o Q •-. HMNHNajHOCOiO £ ,2 & CDOOCNOCOOOOOQOO CO OHHOo j * . COCOCOCOCOt-Ht-It-It-IO d ^i2 33 OOOOOOOOOO g -o£ oooooooooo o 0^£i o o d o o" o o o o o p cN O O b- >« oooooooooo 'I'W+ 0" O Q 0" Q 0" Q 0' Q 0* '^-o !>COCOO'-iOOi-i(NO • Mo ^T^OO>OOiOt^(MCO S_ looooiococoooococo Wf£l2 ^COCOCOO^CO^HOO 0>>o 0lC0H00»OO00^'O(N .d a CO o 'co t> #d l> CO CD cO *co cO o d CO CO O 'o o faC XtH o3 Oi O J^ 00 o o3 O O -^ o "^ O o O rH O O CM o o Ph CQ O ?H O d % °' o" *H d o" O O «2 n- || II *~ II II II II 02 CO co ■s * M "3 * W d *« o3 o3 o3 ■+3 -(J -tJ CO CO co d d d O o o U O O iJW/5 OOOOOOOOOO OM«! oooooooooo "5 o o o o o r-i r-> r-> O O O O So iO O O »C O °- °- °~ O C^ lONiOHiNiOHiNiOH c3 &&ZZ&XZ&ZX 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 289 2.0 3.0 4.0 5.0 6.1 I ll +1 5.0 4.0 3.0 Figure 13. Hydrochloric Acid and Biotite. (See Table 13) 2.0 290 University of California Publications in Agricultural Sciences [Vol. 4 OWC5HN^HO>OCO MHNHOfflOOtOtO") ICO ICO ICO ICO ICO W |rj< ItJh |t*5 |rjH § qj OCOCOC^ CO (N H r- IOOOOO OOOOOOOOO o o o p p p p p o oo'oooooo'o CO 00 i-H CO i-t O y-f OS i— I »0 OS O CO CO (N IO 00 TtH CO ^ CO GO CO H O) OS i— I 00 CO »o iO ^ \t< o o -5^^ I CO ICO I CO ICO I CO I CO ICO I CO I CO 1-tf •5a3 MtOOOHM^NTftcOO ~ p, 00000*0000^000 <* COCOCOOOOIOIi-Ii-HtHO O m £ oooooooooo /o-2 oooooooooo 0§3 do' dodo" dodo OS t- 1-H Cd>d>d>d>d>d>d>d> a O o o o o "S © © © g g g °. g i0 0 0>0 00.0.4o g iQNiOHNiOHNiOH 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 291 2.0 3.0 4.0 5.0 5.0 4.0 3.0 Figure 14. Sulfuric Acid and Biotite. (See Table 14) 2.0 292 University of California Publications in Agricultural Sciences [Vol. 4 . CO u oa dS3 . ^ O 0 •~ iOOOOJiON(NCOOO)GO ^ (NMCOOIC050NNH 0, ICO ICO ICO Irji |^h |rj5 W |Tji |tJ? W BS rt-H £§3 H Eh Eh O S Q <1 to io to OMNOlNiOtOcOMCO ,-<,-ii-iOOOOO©0 oooooooooo oooooooooo ododdoc>c5o'd ft 0|| d^3 00 b- N N (N »0 M tO O ^ CO CO O 35 >o a 1— 1 o C3 o O) § o t-t d © o II II DO -j3 X w o3 +3 GQ R o U bfl 03 .a O X o COOOCOOOrHCOt^l^ ^coocoooi-Htootooo OOr-HCOOt--rHCOi— I © ^ COONiOOOMOHCO id |eq ICO | CO ICO I CO \"# |rjH \r$ |iO "fa to Tti 1> oooooooooo oS3 OOOOOOOOOO ■ ° i>OOOOt^i-HOOOOCOO 2 £ ooon^oom»oh:o(n ^ S-- coioot^o}Oi-iT-icoai . 5 i—3 COOCOO'-HOiOCNiOO W-g ,_, OOO'CrOONN'O'ON Jca ICO ICO ICO ICO I CO W" W |t*h |Tf |tP o §§3 CO (N (N t^ooocococoocooi-H OOCOCOOOCDiOCOCOiO ocococai-iooooo oooooooooo H 5 g g oooooooooo h Oca odd odd dodo I I -a coioH^offi^acoco o .2 £ N^NOiOONOOOCN cd 5 ,rt a oiOHtomwiOHcoco th ^ O TtHor^'-Ht^»oo'-*oco ^ . on »-; COt-iJ^CNCO^ bio35 OOINCCOOONINOM C_=o OOOCO^HOOiOMQOCO ^^< I'M* ICO ICO ICO ICO W W |t}h |iO 1*0 d'C (N M M ■* m CN^MTt*CNHCO^ ■~jg iO CO f) N ■* N CO « O O a a o^cO'+oirHooooo ^ 'A~0 oooooooooo ^J-g oooooooooo oa,< d d d d d d d d d d a o 2 o o o o 2 _ ^ — o o o o o ,c o 8 § S © © °~ <=r X iO Ol iC h C^ >0 h (N "O h s ********** 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 295 2.0 3.0 4.0 5.0 5.0 4.0 3.0 Figure 16. Phosphoric Acid and Biotite. (See Table 16) 2.0 296 University of California Publications in Agricultural Sciences [Vol. 4 g % IOH0001CON0510INO) P-c . 00(NtHM^H(NhN(N • °2 Jrt INCOOOOOONNCOON M"o^ TPOCOCOCOCO3 rttTtf^-tCOt^cDoO^OlM 2>g n COiOOiOiOI^iO'-lTjHO - o3 1-1 ~ ft COH©tOcONMOiOOcO -T3COO o3 CO CO +? © O COCOCN(MC- o o P. P. P. o C »P C7i 00 CD lO ^* *tf "■* t« CO |rf |Tf |Tf |r}H |^ W |t^ |tJh |rt" W -O-S oS3 00 N ■* CD iO 00 "* t« CO CO 00 00 N t^ CO o o o o o o o o o o o o o o o o" o" d d d CO lO C5 H CO O N N N (N CO CO CO CO CO o o o o o o o o o o o o o o o cd d> cd CD ^ 00 O T-H 00 CO CO b- o T— I rH ICO I CO 00 O tH Tt< CD 05 O CD CO CD 00 i— I tH CM iOOMNIN^ h t-H CD t-H 0> © O ^ O © CO N © CO o N ^ ^ lO O0 CM IN |TJH |tJH W' W* |t*' |^ |«tf ,^ CO ""* -HH OS r^ o T-H b- 00 ■CO b- CD of e-2 -P CO <0 CO C0 co 01 t-H t-H i— i o o o o o o o O O o o o Q o o o <3 § "3 o q o o o © © o o O e a d d d d d d d d d S 3 CO i— i lO t-H oo CD t-H 01 O CD £ a> CO CO ~f o as OS b- b- OS lO 03 ft co l^ oc «* co a Ol b- CO t-H ° ri LO "tf 00 CO l> co o b- J2 f-1 MO » OS 00 »o o I- CO- 1—1 X t« CD ~t TjH -« cd cd cd to HHNOJM b- CO Ci 00 to t-H t-H O O O o o o o o o o o o o d d d d d b- Oi co oo ^ to iO CO CO o o o o o o o o d d d oo b- tO b- co o Oi o o o o o o o o o o o o o d d t-h r>. T*H CO o o o o o o o o o o o o o o o o d d CO to t-H t-H o co o o o o o o o o o o o o o o d d b- 05 O CO o tO o o o o CO CD (N »0 rt< C3 00 05 O0 COCOhOOiONCONOO ^NCOOHCOONcOCo HCOffiOOONCOiONO) NcoHOoqcqiocNooio I CO ICO I CO ICO ItJh |o o o >o O °~ °- °- o tOCOiOi-HCOtOT-HCO»OT-H yyyyyyyyyy 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 299 2.0 /♦■ 0/ + / I ^-/o J J -y 3.0 T° / L ♦ / / /+ *"// / * If 7 °T 7 4.0 / 0 $ +/ 5.0 1 1 i 5.0 4.0 3.0 Figure 18. Formic Acid and Biotite. (See Table 18) 2.0 300 University of California Publications in Agricultural Sciences [Vol. 4 Om-h W o a> ^ CO CO ICO ICO CO "o M^ g co -H 03 rj-js OS CO o O oil o d o d H s O 3 o ffl o-2 ICO led « Q 3& *o iO o 00 T-H CO CO t> t^ - |TfH W T^ oo §8 d d o o c lOOOtOHOOCDcCOO (N»OiOONCO^O^O O^ONNOOONCON MOOOtOiOMNOOJ© ICO IrtH |t}^ |rtH Irf |t}5 |tJh |rfi |ia |»0 O t^ r^ rJH CO r^ lO TJ O O O O jag-5 o p q o U-<-< d d d d W-J. N CO © t)( 00 H oo h go o oo ^ co co i-i i-i o o o o o o o o o o o o o o o o o o o o d> <6 d> d> d> d> o >o o o »0 r-> ° ° ° ° Po8°° °. cf IM iO H N >C h <3 ££££££££££ 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 301 2.0 3.0 4.0 5.0 5.0 4.0 3.0 Figure 19. Acetic Acid and Biotite. (See Table 19) 2.0 302 University of California Publications in Agricultural Sciences [Vol.4 w JS ft OCO^MHiONCOrticO U„-. COOTH(NOlOr-IOO^Hi-l m'S & ^mcOHiNHQOINiOCft o£:£ i-|i-Hpposoqi>i>ioi-H ^^^ I CO I CO ICO I CO W |^' |t^ |t^ |t^' |tJH 2 <- 03 03 tH iO lO CO 00 Oi 'O o CCj CO io o co to *o co co i — i o 00 CO co io co i— < O * * i— i i — i o o o o o o dS3 o o o o o o o o o o o o o o o o o o o o d d © d d d d> d: d> d> J2 "3 <- NiO^rHCONNONN ■32 Htooo^HOooo^f >0 OOOOOOOOOO " ^ ^ ,»h WK+ dodo do dodo £ * W o3 §5 •„X I>cOC005t-iOO'-hOOffiii:N(NCO o 2 looooioffltooooMco ^ Kn-S^ ^COCOCOCOCO^HOO »_lW?" OOOOOOOOOO ow*< OOOOOOOOOO 000 o 0000 0000 o o o ,-r g iO O O to O w- w~ w~ o g »OCt^O OOOOHiOOCOCON »0 IO M O © N O O N I CO ICO I CO I CO W l^f" |t}h |tJH |iO ion aoi 05 IO i- iT+HCOiOOOO^O 00 d> c> ci d> o 62 o o o o o M was 00Hi((M05(Mi0iCOi0 cooicoOi-HOoooocoo lOCOrHOt^OOl^i— I ""* t> rjH o r-H CO o X Q -h CO co Ol IC X X IO i^ o o OS O- O CO Ol iO r-H o o o X X X X l> CD o - 03 Q. o to ^^^ | co ico I CO I CO W W W W w" W s .3 fe co co -^ co io io SS ^ooohoooocococoio MoilH rHr-lrHrHOOOOOO o^ oooooooooo cS^S oooooooooo o^w o o d d o* © d d © d 2& O(NOX(Mi0 CO OS X 1> X a ICO ICO ICO ICO Irfn |tJh |>o |i6 W I^O H -tf TtH S M IO X OS OS OS 5j <- s Ol Ol Ol ** iO CO OS CO i-t CD §^ OS o o X iO Ol o o rH O -t *-h CO r-H o o o o o o r- 1,-g (j; O o C1 o o o o o o o o o o o o o o o o o r-} p 3 d d d d d © d d d. d PQ o << o H «1 -* OS CO iO o fj OS CO o CO CO t^ t» t^ co tO CO Ol CO IO H r-H i> r-H eo CO o o o o r^ o Ol CO CO r— 1 o o o o o o <| « 2 «3 2 CO o o o o o o o o o J o o © o o o o o o o ° SO o o o o o o o o o o #3 + d d d d d d d d d o* .2 CO o OS Q OS -* CO CO O} OS W O OS -w X o >o OS co -V OQ OS X t^ CO o CO i — i CO OS 1> .•.'5 -rt -H o Ol iO CO to- cc t^ TjH CO O ni o tr- TJH Ol o X CO. <* Ol o t- 00 5 *o .5 o o O r-H CD O ,™ ^ o O wo rH O O o ■*? II II ^^0 O HlNO^NNNOOHiO "* „ COlOOH©Tf(NHHO S-2^ iCCN'-irHOOOOOO ."S3 oooooooooo -flo3jj> oooooooooo 0^io o o io o °~ °- °- o § lO TtH CM OS iO CO o io oo co HOOOlfflOOOONCOtO ICO ICO ICO |TjJ |"tf' |tJH |Ttn' |tF |t^ |rfH* a oS3 CM tH iO LO CO iocohthoonconooco COOOffiOONCOiO^CO t-h i— it-hoOOOOOO oooooooooo oooooooooo d>cic5d>d>d>d>cicid> n OOiOHOOO^WCONCO NCHOONO^IN^ NOlNHCOHONtOIN iOOONTHOl^OO^N^ NiOOOiO^OHiOOliO cocoiocoososcoosoqos I co I co ico I co W W Ith |id I id |id dS3 -tf CO t- iO o o o o b- CO 00 CM CO CM o o o o i-i CM OS o 00 00 o o o o o o 00 O OS CM O o o o o o o OS b- os o o o o o o o o oooooooooo Tfi iO CM i-i i-i O O o o o o o o o o o o o o co oo CO i— i iO OS ^ 00 N CO co i— i o o o o o o o o o o o o o o oooooooooo o o o iO O O iO o iO CM iO tH CM iO o o o o o o o o o i— I CM IO y— I £ ££££££££££ 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 311 2.0 3.0 4.0 5.0 5.0 4.0 3.0 Figure 25. Formic Acid and Granite. (See Table 25) 2.0 312 University of California Publications in Agricultural Sciences [Vol. 4 Oh-h COHOOCDOOMIOOO^ lOINOOOOJOOlNOO) OOOOOOCCOONNffl ICO ICO ICO W W* lrf |^' |^' |t^" ItJH d^3 O (M i0i0C0ONC0(NO»O |CO ICO I CO I CO ItJH |tJh |tJH |iO |iO 1^' tO lO 00 © © !>OiOTHC^»Ot^00OO t^lOr-H(MCO^i-lOOi-H COCOfMi-iOOOOOO OOOOOOOOOO oooooooooo -go W«1 + a - o to oo oo CO O i—l (M CO TfH to t^ (M O CO o o o o o o o o o o o o o o o o o o o © © © © d OCO(NNHTjiH COOOOCOtocOOQOOCO ICO W W IrJH |r^ |t^ |t^' |t^ |tO |tO 0<<«1 O b- (M 00 CO (MOO O O O o o o odd ^ N W Oi -* 00 h »o oo i— i oo o oo ^ TfH CO (N i-H t-H O O o o o o o o o o o o o o o o o o o o o o o © © © © © © © "5 O 2 o o o o fl © O © g g g °~ g to o o »o o R R R. o g lO(MtOrH(MtOi-l(MtOT-H (3 ££££££££££ 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 313 2.0 3.0 4.0 5.0 5.0 4.0 3.0 Figure 26. Acetic Acid and Granite. (See Table 26) 2.0 314 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 27. Obthoclase and AZOTOBACTER. Time Days Ch, H ion Dextrose +Azotobacter Log. H ion Dextrose +Azotobacter H ion Orthoclase +Azotobacter Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter 0 0.00000282 6.450249 0.000000962 0.000238 4.376577 1 0.00000261 6.416641 0.000000787 0.000675 4.829304 2 0.00000331 6.519828 0.00000161 0.000455 4.658011 3 0.00000359 6.555094 0.000000887 0.000575 4.774517 5 0.00000421 6.624282 0.000000887 0.000852 4.930440 7 0.00000534 6.727541 0.00000197 0.00107 3.029384 9 0.00000627 6.797268 0.00000251 0.00404 3.606381 11 0.00000935 6.970812 0.00000331 0.00198 3.296665 16 0.0000177 5.247973 0.00000389 0.00119 3.075547 Constants for Calcium : x = 1.804 K = 19.77 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 315 4.0 5.0 6.3 4.0 3.0 Figure 27. Orthoclase and Azotobacter. (See Table 27) 316 University of California Publications in Agricultural Sciences [Vol.4 NC5C0003C005CH ' S 0000©©^©^tO© 'a co^mmiNfOoOHO I . NOOCOOOCO^OONCO Peg OOCO»0©COOOOONOO iS^3 |Tj3 |TfH |^ |TfH |Tf |tJH ITJH |t$H |t}H « t, to to to to K5 +> ft N^MTH^NcOtON ^^2 S3 OOOOOOOOO 5,2 ."S OOOOOOOOO O^^l OOOOOOOOO i o q 1-5 fl ft b- CO o X -i- to -H 00 o CO co o >o l> » TO tC I— 1 0! »c A c oc -t lO Ol t> -t1 >o co CO CO o 05 o 00 -t c ~r © c l> i- CO i^ ~ •H 1^ ICO |tJh |^ |rt< I Tin |^ | CO o3 e|+> £53 •Hh Sfl) » « O C ft H H U s < .2 pq '3 ^ 0 En 03 Q, o 0 . CO t-c 65 M-o^ <^ h^>-J Q fe a "< H 3 u H °-§s Eh - O +j 0 dS3 cc MiOOOOJ^tONHO ©000©OCto©©© OOOOiOtHiOOO^O Or-lOOOOO'-HO OOOOOOOOO OOOOOOOOO © © © © © ©'©'©' © to©co»o©ooco©© NCOW-HOICDCONIN ^o^oowoowoco lOi— IOOCOt^©©i-Hi-H oo^ooooowhh OO CO CO CO CO TtH TH TtJ TjH I CO I CO ICO I CO loo ICO I CO I CO Ico to OOOM^WtOOOOO OON'HH^ffiNiOtO i-HOOOOOOOOCOOOOOOO ©©©©©©©©© ©©©©©©ooo <5d>d>d>d>d> 00 © .5 1—1 OO © IS o ~ Tt< © b- © Q CO © ?H © © s CD a bJD 00 o3 OO 00 ^h i-h CO ©C0 led led led ltd led led led led I to 4-*S 2^5 Xt ° -8 "8 .4 © i—i © 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 317 4.0 _ 5.0 6.3 4.0 3.0 Figure 28. Biotite and Azotobacter. (See Table 28) 318 University of California Publications in Agricultural Sciences [Vol.4 o r, u iO0000©O©(X)iOiO §OiO"OCOO© £ ft cOi-HCDOOOOOOS •i2 §3 OS b- iO O O O 10 OS 10 iJ^3 |id |«* |t(5 ItJH* |tjh |tJh |tJh |^ |rt< flS ffiMCHHHlOffilO OWCOCOWCOMCOrJi ooooooooo ooooooooo ooooooooo O^t-3 ooooooooo lOiOCOOOOOi— i ■* »o OMCQiO^NINOOO CONNO^ONOON ■^OOOOSOCOOCOO? OSOs^OCO»OCOOQO OOOOOOOOr-JrHO |t^ |rfH |TfH |rfH |rh |CO I CO I CO I CO o z u ioeqco t- O -r Ol '3 00 1^ oo 01 01 00 t^ os >o IO t^ Ol i — i O 00 I - o co »o T*< <* 1- OS IO t> c3 o o o o o o l—{ o i — i T— I Ol o o o o o c o o O o o 5-1-1 i— I d (D-^ o o o o o o o c o .2 §«! o o o o o o o o o II ■■ - o o o o — o o o ii o o o o o q O o o -f^ X M d d d d © d d © d <3 OS ^H oo Tt< Ol ,_, x 01 CO DO 0 .2 vx> ~v -t Ol OS X rjn - i—i t^. o Ol SO X O Ol •O Ol 00 OS o o CD OS >o -h l> l> o t^ bf]~* N iC T— I IO "< TjJ -H o IC o l> t^- OS (M ^Q + id id id id id id id id id 5 m h h o ^r^io O £-g OOOOOOOOO ,HoS ooooooooo pdio ooooooooo -*i3 ooooooooo ■?v< ooooooooo OQ + ddddodddd | gj OHNCOiON HP 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 319 4.0 5.0 6.3 4.0 3.0 Figure 29. Granite and Azotobacter. (See Table 29) 320 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 30 Calcium Silicate AND AZOTOBACTER Time Days Ch, H ion Dextrose +Azotobacter Log. H ion Dextrose +Azotobacter H ion Calcium Silicate +Azotobacter Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter 0 0.00000282 6.450249 0.0000000778 0.00142 3.152288 1 0.00000261 6.416641 0.0000000778 0.00201 3.303196 2 0.00000331 6.519828 0.0000000912 0.00186 3.269513 3 0.00000359 6.555094 0.0000000912 0.00196 3.292256 5 0.00000421 6.624282 0.0000000112 0.00279 3.445604 7 0.00000534 6.727541 0.0000000941 9 0.00000935 6.797268 0.000000107 0.00396 3.597695 11 0.00000935 6.960812 0.0000000778 0.00396 3.597695 16 0.0000177 5.247973 0.000000731 0.00406 3.695482 Constants for Calcium: x = 1,280 K = 0.03381 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 321 4.0 5.0 6.3 4.0 3.0 Figure 30. Calcium Silicate and Azotobacter. (See Table 30) 322 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 31 Orthoclase and B. Coli Time Days Ch, H ion Dextrose +B. Coli Log. H ion Dextrose +B. Coli H ion Orthoclase +B. Coli Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter 0 0.00000261 6.416641 0.000000962 0.000694 4.841359 1 0.000301 4.478566 0.000141 0.000753 4.876795 2 0.000486 4.686636 0.000267 0.00206 3.313867 3 0.000505 4.703291 0.000339 0.00230 . 3.361728 5 0.000505 4.703291 0.000289 0.00224 3.350248 7 0.000467 4.669317 0.000278 0.00270 3.431364 9 0.000414 4.617000 0.000237 11 0.000467 4.669317 0.000313 0.00282 3.450249 16 0.000431 4.634477 0.000179 0.00271 3.432969 Constants for Calcium: x = 1.690 K = 13,490.0 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 323 4.0 5.0 4.0 3.0 Figure 31. Orthoclase and B. Coli. (See Table 31) 324 University of California Publications in Agricultural Sciences [Vol.4 OiCOCO»O^CDOOM 10MC0003CONNO Oft HHCOOOtOcOOlOO Ph- OHNOcOtOOOOO® ■Ji 3 N(N(N(ONOOOOH Mo-g NiOiCOOcDtOtON ■J§"3 W l^t* ItJH |tJH |tJh ItJH |t}* l^jn W §« INCONiONOOOON -^> ft lOCO^^^^iCiOiO P ■ ooooooooo P^s ooooooooo s,°,.t3 ooooooooo o"^^ ooooooooo £P§ H rHOOt^t^i-HOi-ICiO ,5^.2 oooooooowioooo^ gg'H ocooonHCQOOO .3^1 COiOOOOOCOCO'* htrg u OiOOOOOOOO ^ c a Ico Itjh' |tjh |«* \t£ ico ico* ico Ico* , *i «_ CO (X) N N N iO CO CO m^ 5 ooooooooiO'-h o3 d-£ OCOOOOOOOOi— I H 5gj T-lOOOOt-lr-I^HrH ^.2M ooooooooo 5 8 S3 OOOOOOOOO j S o .2 U '3 p CM JS ft CO ffl CO M w Q h3 fc PQ < B •3 O S 00 O O Ph 00 0 ?-< 1-J GO* ?-< ^h Th Sh 0 © O O O *■- II II II II =4-1 II II CO co CO ■s * M 1=1 X W +3 X M c3 c3 o3 -P ■+3 +^ co CO co a fl fl 0 0 O 0 0 O ^Q + ^COcOHt)IMM^O i-HCOcOOiOoOi-il^t^ cOiOcOMroiO^OcD COOOOCOoOCOOiOCsl hnooonioconco TflXtHC01^1>t^l>t^l> ICO |Tj" |rj" |rj" |tJ* |Tt" W* ITJH |TJH* CO C (NHcD>OiON^NOl o &;3 OOOOOcocOGOOb- '"00 OW^'OiCiO'OtO'O Mt-o ooooooooo _*~ ooooooooo j«)P9 OOOOOOOOO OQ+ ooooooooo* HQ O H (M M lO N 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 325 4.0 5.0 4.0 3.0 Figure 32. Biotite and B. Coli. (See Table 32) 326 University of California Publications in Agricultural Sciences [Vol.4 t< iO ■>* *C to CO rt< 03 O 0« NOONCDO^NOOCO • ,, OOCOOOtOiOiOINCOO o^cK oOHNNioiocqcqco W' I eo I co I co I co ico i co led Ico OiWi— I 00 lO ^ O H 00 NNCOffiCOOiHHO O i— I r- 1 i— l M W ■* ^ •* ooooooooo ooooooooo o^3 ooooooooo s 00 CO CO >o T— 1 •a & 1- OS X t> 01 10 OS 01 0 ic I- Ol l> CO 0 CO 10 "t OS l> CO -f CO co T^ H Ol r> co CO 0: 00 00 cr. 0 ^M 1 — 1 T— 1 ItF W ico Ico Ico ico Ico Ico Ico •j s 2 Jh ** o "3 c -1H 0 ^H t^ CO 0 CO CO o •3 a CD CO 01 CO CO -H 10 • 0 to °."|| 0 0 CO 0 0 0 0 0 0 0 0 0 CO W d^3 0 0 0 0 q 0 0 0 0 W Q 0 0 0 0 0 0 © © 0* ^ fc PQ < i «! P tg H H CD '0 0 s 0 1$ 3 0 CO 00 CO 00 0 t^ 0 03 0 H .rt 0 lO r- I- l> X co co t^ o _2"o 0 1— 1 01 CO 01 01 Ol co 1—1 0 0 a • 0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 •2gm 0 0 O 0 0 0 0 0 0 +3 Wo + © 0 0 0 0 0 0 © © o3 .2,.- «"* CO CO 1 — 1 _, H 0 !^ t^ 02 rH CO co OS OS 1^ 0 1 — 1 t^ 0 Wgl co >o CO O) 01 CO 0 co "tf 0 co 00 CO co co OS 1^ OS T^ . +i . ^H 1^ 00 0 0 CO , — I CO CO £?Sffl "**! rfH CO I- I- co CO CO CO ^Q + led ItJh |t^' |«^ Irf! |^' |rt" W" I^JH 01 o r3 10 »o t- CO 00 o d © C3„ ©HCOiOiON^NH °m~ C<100000COr-icOCO Wiu ooooooooo _*.-• ooooooooo OQ+ o 0- 0- 0- 0* ,-j <-; 0- 0- 0J 03 HP 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 327 4.0 5.0 4.0 3.0 Figure 33. Granite and B. coli. (See Table 33) 328 University of California Publications in Agricultural Sciences [Vol. TABLE 34 Calcium Silicate and B. Coli Time Days Ch, H ion Dextrose +B. coli Log. H ion Dextrose +B. coli H ion Calcium Silicate +B. coli Ca, Calcium Mols. per Liter Log. Calm Mols. per Liter 0 0.000000261 6.416614 0.000000220 0.00337 3.527630 1 0.000301 4.478566 0.0000716 0.0108 2.033424 2 0.000486 4.686636 0.0000564 0.0397 2.598791 3 0.000505 4.703291 0.0000687 0.0526 2.720986 5 0.000535 4.728354 0.0000806 0.0723 2.859138 7 0.000567 4.753583 0.0000745 0.0848 2.928396 9 0.000584 4.766413 0.0000716 0.0972 2.987666 11 0.000597 4.775974 0.0000716 0.1018 T.007748 16 0.000579 4.762679 0.0000635 0.1238 1.092721 Constants for Calcium: x = 5.070 K = 1,667. X 1011 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 329 4.0 5.0 3.5 2.0 Figure 34. Calcium Silicate and B. coli. (See Table 34) 1.0 330 University of California Publications in Agricultural Sciences [Vol. 4 TABLE 35 Orthoclase and B. Lactis Acidi Time Days Ch, H ion Log. H ion Dextrose Dextrose +B. lactis acidi +B. lactis acidi H ion Orthoclase +B. lactis acidi Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter 0 0.00000421 6.624282 0.000000354 0.00147 3.167317 1 0.0000157 5.195900 0.00000935 0.000912 4.959995 2 0.000228 4.357935 0.00000967 0.000852 4.930440 3 0.000398 4.599883 0.00000967 0.00162 3.209515 5 0.000642 4.807535 0.0000217 0.00228 3.357935 7 0.000696 4.842609 0.0000170 0.00235 3.371068 9 0.000696 4.842609 0.0000192 0.00249 3.396199 11 0.000789 4.897077 0.0000244 0.00271 3.432969 16 0.000642 4.807535 0.0000286 0.00210 3.322219 Constants for Calcium : x = 0.867 K = 0.0006652 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 331 4.0 5.0 4.0 3.0 Figure 35. Orthoclase and B. lactis acidi. (See Table 35) 332 University of California Publications in Agricultural Sciences [Vol.4 Oft oiocomiooMioo P-i- IMNiNOJOiOCOINiO Wo-£ CONNN0000000000 i-]§J |tJH |tJH |t*H |t* |t^' |t*h |th" |r^' |rji £ .2 '55 § & Oi-HCN^HcOOCOOOO +? ft -fiO©>OONN(ON jg ■ ^ OOOOOOOOO ^i£ £ OOOOOOOOO 5,5 .-S ooqqqpqqo Orf>-3 o" O O O O O O O o" I o (N -t ,_| 0) -t< OS OS os (M CO ■ O o tO o o -fi co OS CO -f -f o CO os 01 iO C '0 1 — 1 1 — 1 TjH CO os TjH W as o 00 o 1— 1 i-H H 1— 1 PQ pq Irjn ICO W ico loo Ico Ico ico ico a o as CO CO a _2 -f (^ -+ o -f id CO o o o o o 1 — 1 o Ol CO CO CO as O U O -HI o o o c o o o o o a>o o o o o o c o o o PIS § o o o o o o o o o o-g-; o c o c o o o o o t3 o o o o o o o o o d d d d d d d d d CI o 'O CO >o OS o r- to '" S.2 oc o CO 00 co o o i- CO W g-g Ol os os 00 to CO CO o to bi)Xj3 -t >o t^ os 1^ Ol 01 l> i> (N os lO OS c ■^ ^H OS o CO Ice iC CO It*h IO OC l-f-' oc It* oo oc oo IrW OS CO to t^ o o o CO O 28 II II M , '3 (N fi+rt ^toooooc^cocoas^ O^co OHC1C5OO0500O — o'^3 OOflCOTP^TfNO mjho OOOOOOOOO "KiH OOOOOOOOO £o . OOOOOOOOO oqm odd odd odd .5 «' OHiMcOiONOJHcO 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 333 3.0 Figure 36. Biotite and B. lactis acidi. (See Table 36) 334 University of California Publications in Agricultural Sciences [Vol. 4 c ifl iO N ffl ffl N H ©■00 t-P. "*ONHCOCOHNH h-n-2 S3 CO O O 00 iO O OS t^ O g'o-g M"300N©005000 i-}2^) Irtn |rt< |rtH |tJh |rJH |co W Irjn I CO ft OON iO ^ IN -^i-l |rfi |tJH W W |t^ W |tj5 I'*' |rH O 2^ t^coco^coco^co^o' 02 uj HN®M»ONM O wow dodo o dodo g * ^ S * ^ ^ ■+= += _, , *3 mm §+o3 NOiOCOiOOiOSN'O C ri •"(UcoOOOCOoOCOOOt^CO o o hrig-rtfNOOoOiOOcOOiO Q Q m"S^ (MOiOOO^^OO g3* ©HMiOOOOOOOCOCO iJQPQ |d 1*6 \«$ l^fH l"tf W ItJh IrtH |rji 3 rH j_» (N N GT"3 TfiiOOOOOINtOtDOJN ° rc 22 Ot-i(M05^OO00t1h oV OOC^COCDOOt^CO E£ £ ooooooooo „K,2 OOOOOOOOO ^ • ooooooooo uh« doddodddo* 0> CO £ rt OHNCOiONffiHffl 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 335 4.0 5.0 4.0 3.0 Figure 37. Granite and B. lactis acidi. (See Table 37) 336 University of California Publications in Agricultural Sciences [Vol.4 TABLE 38 Calcium Silicate and B. Lactis Acidi Time Days Ch, H ion Dextrose +B. lactis acidi Log. H ion Dextrose +B. lactis acidi H ion Calcium Silicate +B. lactis acidi Ca, Calcium Mols. per Liter Log. Calcium Mols. per Liter 0 0.00000421 6.624282 0.0000000877 0.00229 3.359835 1 0.0000157 5.195900 0.000000136 0.00248 3.394452 2 0.000228 4.357935 0.000000142 0.00475 3.676694 3 0.000398 4.599883 0.0000000778 0.00416 3.619093 5 0.000642 4.807535 0.0000000778 0.00486 3.686636 7 0.000696 4.842609 0.0000000411 0.00554 3.743510 9 0.000696 4.842609 0.0000000544 0.00545 3.736397 11 0.000789 4.897077 0.0000000544 0.00525 3.720159 16 0.000642 4.807535 0.0000000544 0.00565 3.752048 Constants for Calcium : x = 0.170 K = 0.0000002710 1922] Wright: Equilibrium Studies With Certain Acids and Minerals 337 4.0 5.0 4.0 3.0 Figure 38. Calcium Silicate and B. lactis acidi. (See Table 38)