small changes as certain as where the change was more pronounced. Adsorption from solution: D. C. LICHTENWALNER, A. L. FLENNER AND N. E. GORDON. Varying concentrated solutions of calcium sulphate, calcium acid phosphate, magnesium sulphate, magnesium acid phosphate, potassium sulphate, and potassium acid phosphate were shaken with alumina hydrogel and iron hydrogel and the maximum adsorption determined by analyzing the solution before and after shaking. The water of hydration was all figured as water of dilution. gels show large adsorptions for each radical, and especially was this true in the case of the phosphate radical. The adsorption increased with increase of concentrate. The slow process of establishing equilibrium was also greatly marked. Both Effect of hydrogen-ion concentration on adsorption: E. B. STARKEY AND N. E. GORDON. Hydrated gels of iron and silica were prepared in a very pure condition and shaken with a N/20 solution of KNO, K2SO, KHPO,. The hydrogenion concentration had been varied by the introduction of sodium hydroxide or hydrochloric acid as the case might allow. The adsorption of each ion was followed by analyzing the solution before and after the shaking and figure the water of hydration as water of dilution. It was found that the adsorption of the metallic ion decreased with an increase of hydrogen-ion concentration, while the nitrate, sulphate, and phosphate radical varied between no change of adsorption as in the case of the nitrate radical to a very noticeable change of adsorption in the case of the phosphate radical. The sorption of toluene and acetic acid and their mixtures by carbon: A. M. BAKER AND J. W. MCBAIN. A general method is described for determining the true sorption of both solvent and solute in place of the merely relative values obtained in the usual way for solutions. A maximum value for sorption is obtained which is independent of the absolute temperature; the ratio between the saturation values is that of the molecular weights (acetic acid being present as double molecules); and when solutions are employed, the total amount sorbed still corresponds to a complete monomolecular film in which a certain number of double molecules of acetic acid have replaced a corresponding number of molecules of toluene. Drop weights of oils in solutions of emulsifying agents: ROBERT E. WILSON AND ALLEN ABRAMS. The preparation and properties of ferric hydroxide gel: ROBERT E. WILSON, WILLIAM B. ROSS AND LEON W. PARSONS. The measurement of the plasticity of clays: ROBERT E. WILSON AND F. P. HALL. The transitional temperature of the sol and gel forms in gelatin: ROBERT HERMAN BOGUE Bingham has shown that viscous liquids can be dis tinguished from plastic solids by a measurement of the viscosity at varying pressures and an extending of the curves downward till they intersect the axes. The former type intersect at the aper of the viscosity-pressure axes, while the latter type intersect upon the viscosity axis. By applying the principle to gelatin solutions at different temperatures and employing the MacMichael viscosimeter at varying speeds of rotation in place of the capillary type at varying pressures, it is found that the gelatine follows the law for a viscous liquid at temperatures above 33 degrees C., while at lower temperatures it follows the law for a plastic solid. On the swelling and gelation of gelatin: ROBERT HERMAN BOGUE. Gelatine sols were treated with solutions of the silicates of sodium in which the Na2O: SiO2 ratio varied regularly from 1:4 to 1: 1. The swelling, viscosity, alcohol number, and PH values were determined. The data indicate that the effects resulting from such additions are due in all cases to changes in the PH rather than to any other influence of the silicate. Gelation appears to be dependent upon the tendency of the substance to become solvated, the volume oecupied by unit weight of dispersed phase being the determined factor. When this volume is very small or very large, the jelly consistency will be low, and at intermediate values of volume per unit weight the jelly consistency will reach its maximum. Plasticity of colloids: EUGENE C. BINGHAM. The fluidity-pressure curves of gelatine solutions: S. E. SHEPPARD, FELIX A. ELLIOTT AND HARRY D. GIDEOUSE. Gelatine solutions were studied whose concentration varied from 1 per cent. to 8 per cent. at temperatures of 25°, 28° and 30° C. The fluidities were measured with an Ostwald type viscometer under pressures up to 900 mm. water. Ordinary, de-ashed and a mixture of de-ashed and autoclaved de-ashed gelatines were used. All measurable solutions showed little evidence of plastic flow, the curves being linear and approximately intersecting at a common point. The method of preparing the solution was shown to influence the slope of the curves. The action of dilute chloride solutions upon silver chloride: GEO. SHANNON FORBES AND H. ISABELLE COLE. The potentials at the junctions of chloride solution: D. A. MACINNES AND Y. L. YEH. E.m.f. measurements were made on cells of the type: Ag/AgCl + MCI L M'Cl=AgCl/Ag (in which M and M' are the alkali metals and hydrogen) using a flowing junction similar to that developed by Lamb and Larson. With widely varying rates of flow the potentials were constant to 0.02 mv. for indefinite periods. With equal concentrations on both sides of the junction and assuming the chloride ion activity to be the same in all the solutions the measured e.m.f. is that of the liquid junction only. The results may be expressed by a simple additive relation in the few cases in which the formula of Lewis and Sargent does not hold. New Electrometric titration of ortho-phosphoric acid: E. T. OAKES AND HENRY M. SALISBURY. curves for ortho-phosphoric acid titrated with sodium hydroxide and sodium carbonate are shown. These curves are plotted to show observed e.m.f. values as well as РH values. Condenser method, and saturated calomel cell are used for measuring e.m.f. Technic of titrations, method of calculating results and sources of error are discussed briefly. Curves obtained by titrating phosphoric acid with sodium hydroxide, and sodium hydroxide with phosphoric acid are not mirror images. The second end point of phosphoric acid required more than twice as much alkali as the first. Curves obtained by titrating phosphoric acid with sodium carbonate, and sodium carbonate with phosphoric acid are vastly different. Equations conforming to these curves differ from those commonly accepted. Oxidation-reduction potentials of certain indophenols and thiazine dyes: BARNETT COHEN AND W. MANSFIELD CLARK. A series of indophenols consisting of the condensation products of paraamino phenol with phenol, o-cresol, m-cresol, ochlorophenol, guaiacol, thymol and carvacrol were synthesized. The potentials of mixtures of each of these with its reduction product were measured with a gold electrode at different РH values. It is shown that the same general relations hold that were found by Clark in the study of methylene blue and indigo sulfonate, the potentials being a function of both the ratio of oxidation product to reduction product and of the hydrogen-ion concentration. The effect of substitutions in changing the characteristic potentials is noted. Previous work with methylene blue has been extended to other thiazines. Characteristic constants for thionine, gentianine, toluidine blue o, thiocarmine R, methylene green G' and new methylene blue N have been established. Oxidation-reduction potentials of sulfonated indigos: M. X. SULLIVAN AND W. MANSFIELD CLARK. A trisulfonate and tetrasulfonate were found to have identical characteristic potentials when each was in definite ratio to its respective reduction product. These potentials are distinctly more positive than those of mono- and disulfonates. potentials of the mono- and disulfonates are approximately the same but more refined measurements will have to be made to distinguish them. The A series of oxidation-reduction indicators: W. MANSFIELD CLARK AND H. F. ZOLLER. It is shown that certain dyes are as susceptible to precise electrode study as are certain inorganic oxidation-reduction combinations. The great importance of bydrogen-ion concentration is emphasized. The potentials for each dye can be reduced to a characteristic value from which there may be calculated the hypothetical hydrogen pressures in equilibrium with the oxidation-reduction products. These values are used in the form log (1/H2) to which is given the symbol rH. Plotting the equilibria on the rH scale gives a picture of oxida tion reduction indicators comparable with that of the acid base indicators plotted on the PH scale. The following oxidation-reduction indicators were shown plotted on the rH scale: guaiacol indophenol, o-cresol indophenol, o-chloro indophenol, methylene green, thionine, methylene blue, indigo tetrasulfonate, new methylene blue, indigo disulfonate, neutral red and safranine. These constitute a series from rH 21.7, at the more oxidative end to rH 2.8 at the more reductive end of the scale. Selenium galvanometric colorimeter: ALEXANDER LOWY AND OSWALD BLACK WOOD. A submerged floating equilibrium bob that adjusts its weight to the density of the liquid in which it is placed: C. W. FOULK. This is a modification of the Richards floating equilibrium bob so that it can be used for the determination of the density of liquids over a considerable range. Preliminary experiments show that measurements of density can be made with it with an accuracy of one or two in the fifth decimal place and probably in the sixth place, and that a given bob as modified will cover a range of about two decimal places, that is, with one instrument, for example, densities ranging from 1.00001 to 1.00010 could be read. The modification consists in attaching a light chain to the bob which is a fish-shaped, hollow glass, or silica bulb. It is evident that if the weight of such a bob (a certain amount of ballast is usually necessary) is approximately that of an equal volume of the liquid in which it is placed, it will assume a position of equilibrium be tween the surface of the liquid and the bottom of the containing vessel, the equilibrium being brought about by the chain suspended from its lower end. As the bob rises it lifts the chain link by link off the bottom of the vessel till the added weight counteracts the upward tendency and of course the reverse takes place if the bob tends to sink. A practical instrument utilizing this principle is made by having the bob in a tube open at both ends and with one end of the chain attached to the lower end of the tube, so that it hangs in a loop (catenary curve) between this point of support and the bob. The density of a liquid in which this instrument is placed can be determined by noting the position which the bob takes with respect to a scale on the tube. There are a number of interesting variations of the instrument that can not be given in a brief abstract. The comparative value of different specimens of iodine for chemical measurements: C. W. FOULK AND SAMUEL MORRIS. Iodine was purified in various ways as described in the text-books of analytical chemistry and these preparations were then compared through the medium of a sodium thiosulphate solution with a specimen of iodine that had been purified as if for an atomic weight determination. Several new modifications of apparatus for purifying and drying iodine were also devised. The general conclusion drawn from the experiments was that the so-called "analytical'' iodine is remarkably pure. Doubt, however, is thrown on the use of a sulphuric acid desiccator as a method of drying iodine when the water it contains had been entrained through the solidification of the iodine in the presence of liquid water. Variation of grain size in photographic emulsions in relation to photochemical and photographic properties: E. P. WIGHTMAN, A. P. H. TRIVELLI AND S. E. SHEPPARD. The physico-chemical properties of strong and weak flours III. Viscosity as a measure of hy dration capacity and the relation of the hydrogenion concentration to imbibition in the different acids: Ross AIKEN GORTNER AND PAUL FRANCIS SHARP. In continuation of the work reported at the Chicago meeting of the Society, the authors have applied the use of the viscosimeter to the study of hydration of the emulsoid colloids present in wheat flour. Instead of using the washed out gluten as in previous work a 20 per cent. suspension of the entire flour was used in the present study. The results indicate (1) that the viscosimeter affords an accurate and rapid means of measuring imbibition, (2) the form of the viscosity curves is identical with that of the imbibitional curves obtained previously by weighing gluten discs, (3) "strong" flours give greater viscosity values than do weak flours at the corresponding concentration of acid calculated on either normality or hydrogen-ion concentration basis, (4) when the viscosity is plotted against hydrogen-ion concentration instead of against normality of acid a radically different form of curve results, with a maximum viscosity at about PH 3.00, (5) the same value for maximum viscosity is not reached by all acids at the same hydrogen-ion concentration, (6) the order of the acids as influencing imbibition (lyotropic series) is not the same for all of the flours studied. = An interesting colloid gel: Ross AIKEN GOBTNER AND WALTER F. HOFFMAN. A rigid gel can be prepared from di benzoyl 1. cystine containing as little as 0.15 per cent. of the compound. Viewed by dark field illumination this is ap parently a crystal gel. It is suggested that this material may assist in studies regarding gel structure for it can be easily prepared in pure cystalline form and is consequently not affected by previous history as is gelatin, agar, etc. Are electrolytes completely ionized at infinite dilution? HAROLD A. FALES AND HAROLD E. ROBERTSON. Measurements made on hydrochloric, acetic, sulphuric and phosphoric acids up to a dilution of three million liters per mol, by the electromotive force method using the ballistic galvanometer, show that the thermodynamic ionization passes through a minimum and approaches zero with increasing dilution. It seems that it is not until a dilution of one thousand liters per mol is reached that the thermodynamic concentration of hydrogen ion becomes equal to the ionic concentration. CHARLES L. PARSONS, Secretary SCIENCE Molding Sand Research; The Bayard Dominick Marquesan Expedition; Lectures by Professor Lorentz at the California Institute of Technology; The Secretaryship of Sigma Xi Scientific Notes and News.. University and Educational News. An English Translation of Helmholtz's MacLeod on Physiology and Biochemistry in Modern Medicine: DR. J. C. AUB. Stensiö on Triassic Fishes from Spitzbergen: DR. ROY L. MOODIE.. 569 570 573 575 575 577 578 582 584 MBS. intended for publication and books, etc., intended for review should be sent to The Editor of Science, Garrison-onHudson, N. Y. THE PRESENT SITUATION IN FORESTRY, WITH SPECIAL REFERENCE TO STATE FORESTRY 1 No nation can prosper or even exist in comfort without wood, without a considerable supply of relatively inexpensive timber. Three years ago our per capita annual consumption of wood was about 300 board feet, exclusive of large quantities used for fuel, paper and a multitude of other purposes. It is extremely difficult for our minds to picture what this means in total volume or amount when multiplied by 110 million, our present population. Each year we remove from our forests or destroy through forest fires about 56 billion board feet of timber large enough to saw into lumber. This almost incomprehensible amount of wood disappears from our forests every year. Much of it we need and use, and can not very well get along without. On the other hand much of it is destroyed by fire. The latter is not only a great immediate economic loss and waste, but also an encroachment on supplies that will be very much needed in the immediate future. As a nation we have grown to our present stature on a lavish diet of wood. We use more wood than any other nation on earth. Our industries would stop, our very civilization stagnate were we suddenly deprived of our wood supply. Wood the world over is a basic resource. It is almost the first resource to be exploited and utilized in the development of a new country. Moreover, it is the resource that makes possible the utilization of other resources. There is scarcely an industry that can prosper without wood. Agriculture, transportation and commerce as we know them to-day are inconceivable without wood. All of us are daily in contact with wood wrought into some form for our comfort or necessity. From 1 An address delivered in the School of Citizenship, Yale University, Wednesday, October 26. morning until night wood in one or another of the diverse forms into which man has shaped it is influencing your life and mine. If we trace the progress of industrial development in the civilized nations of the earth we are impressed by the apparent fact that: 1. Industrial development proceeds faster in countries when domestic or imported wood is available in considerable quantities. 2. Industrial development becomes arrested when available wood supplies are reduced below the essential needs of industry. China at one time was well wooded. Prior to the exhaustion of her timber supplies she reached a stage in civilization and economic development beyond that of most other nations. She exhausted her forests centuries ago and has been without wood adequate for her essential needs for many generations. Historians have assigned many reasons for the early arrest in economic progress by the Chinese. It appears, however, that the progressive destruction of her forests far below the point of essential wood needs made the development of other industries impossible or extremely difficult. Japan, on the other hand, although surpassed in civilization and industry by China during the long period while Chinese wood was available in quantity, has never exhausted her forests and now has wood in abundance. There is every reason to believe if Japan had followed China's example and had devastated and exhausted her forests and made no provision for regrowth, we would hear little of Japan to-day as a world power. Greece, once powerful and prosperous, fell from her high estate centuries ago. She swept the forests from her hills and mountains in attaining her power and in building her civilization and did not make provision for regrowth. She destroyed her forests, she neglected regrowth and lost her place in the sun. She is still without adequate wood for her essential needs. Switzerland, a small nation of mountains and hills, though poor in soil and most other resources upon which the strength of a nation depends, has retained her forests. She still has wood, a basic resource. She is prosperous and forward moving. The republic of Switzerland, only a little larger than the state of Connecticut, has three million people tilling less than 20 per cent. of the land. Some of her forests were organized as early as 853 A.D. They have been continuously under timber production for more than 1000 years and are more intensively managed and more productive to-day than ever before. The government assumes control over all absolute forest land and the following three requisites are a part of the forest laws: (a) The forests must not be divided in area or broken up by sales. (b) The volume of the cut must be prescribed and the fellings must follow a plan which maintains a growing stock of trees. (c) All areas cut must be promptly restocked. The forest laws of Switzerland declare that her forest area must not be diminished but the private owner can demand that his forest be bought by the public if he feels unable to manage it under laws which insure its perpetuation. These laws have for their object the maintaining of the forest in area and with stocked stands of growing trees. England, though a leader among nations in economic and industrial development, has reached her place of eminence in world affairs without maintaining an adequate domestic supply of wood. Great Britain, an island empire, the first sea power of the world, has been able to meet the need of her industries for wood by bringing it from the four ends of the earth. The recent war, however, has shown her the necessity for domestic wood resources and she is now expending millions of pounds in refor estation. America was blessed with abundance of wood when settlement began early in the seventeenth century. More than half of what is now the United States was covered with virgin forests, composed of a great variety of species, many of which are unexcelled for lumber and other essential products. We have been called a nation of home builders; we have built our homes out of the forest and we have kept them warm with wood cut in the forest. We have been more lavish in the use of wood than any other nation. We have used and destroyed the |