MAGNETISM.-Terrestrial magnetism, United States magnetic tables and charts for 1915. DANIEL L. HAZARD. U. S. Coast and Geodetic Survey. Spec. Publ. No. 44. 1918.

This publication contains the results of observations made in the prosecution of the magnetic survey of the United States to the end of 1915, with corresponding values for January 1, 1915; the collected results of observations at repeat stations used in determining the change of the magnetic elements with lapse of time; the secular change tables used in reducing the observed values to the common epoch January 1, 1915; and five magnetic charts showing graphically the distribution of the magnetic declination, dip, horizontal intensity, vertical intensity and total intensity in the United States on January 1, 1915. On the declination, dip, and horizontal intensity charts there are also lines showing the annual change of those elements in 1915. In addition to the results obtained by the Coast and Geodetic Survey the collection includes all available results of high grade from observations made by others in the United States and adjacent land and water areas, including those at stations in Mexico, Central and South America used in the construction of the isogonic chart of the West Indies published in 1914. D. L. H.

Bur.

SPECTROSCOPY.-Wave lengths in the red and infra-red spectra of iron, cobalt, and nickel arcs. W. F. MEGGERS and C. C. KIESS. Stands. Sci. Paper No. 324. Pp. 15. 1918.

It has long been known that the sensitiveness of photographic plates to yellow, red, and infra-red light may be increased by staining the plates with certain dyes, but the use of such stained plates in spectrum photography has not been very common. The long wave regions of the arc spectra of ferrous metals were recorded on plates stained with pinacyanol and with dicyanin. The photographs were made in the first order spectrum of a concave grating with 645 cm. radius of curvature. Exposures of ten minutes duration sufficed to register the spectrum up to 7000 Å; between 7000 Å and 9000 Å, twenty to thirty minutes' exposure was sufficient; while five to ten hours of exposure recorded many lines whose wave-lengths exceed 10,000 Å, or one micron. In the arc spectrum of iron, 298 lines were measured between the wave-length limits 6750 Å and 10,689 Å; 606 lines were measured between 5503 Å and 11,623 Å in the arc spectrum of cobalt; and 290 lines between 5504 Å and 10,843 Å in the arc spectrum of nickel.

W. F. M.

MYCOLOGY.-Aspergillus fumigatus, A. nidulans, A. terreus n. sp.

and their allies. CHARLES THOM and MARGARET B. CHURCH. Amer. Journ. Bot. 5: 84-104, figs. 3. February, 1918.

After comparison of a large number of strains in culture, the authors have grouped three series of them under two old and one new specific name. Cultural reactions for A. fumigatus and A. nidulans are given. An ascosporic form with the conidial morphology of A. fumigatus is described together with three ascosporic strains with the conidial morphology of A. nidulans and slight differences in size and markings of ascospores. Aspergillus terreus, a cinnamon or avellaneous form widely occurring in soil, is described. The constant occurrence of these three groups of strains in soil cultures led to experiments which showed these forms, together with five strains of A. flavus, A. clavalus, A. oryzae, Penicillium luteum, P. pinophilum, and three strains of the Citromyces section of Penicillium, to grow and fruit readily upon and in three types of soil used in laboratory culture. Full citation of the original literature of these species and types either confused with them or presumptively related to them are given.

C. T.

ENGINEERING.-Ground connections for electrical systems. O. S.

PETERS. Bur. Stands. Tech. Paper No. 108. Pp. 224. 1918. This paper contains the results of an investigation of methods of grounding electrical systems for protective purposes, made with special reference to the National Electrical Safety Code. The subject is taken up under the following main topics: (1) Resistance of ground connection; (2) their uses and service conditions; (3) different forms of ground connections and the electrical characteristics of each; (4) mechanical construction; (5) inspection and testing; (6) fire hazard and interference with service; (7) costs; (8) bases for specifications; and (9) field measurements of the resistance of ground connections. The section on field measurements is perhaps of greatest interest to practicing engineers, and contains results of resistance measurements on types of ground connections now in use in thirty-seven cities in different parts of the United States. In comparatively few places is it possible to obtain adequate protection from electrical dangers by means of grounds made with electrodes of small extent, such as driven pipes, plates, and other devices. To obtain protection which is continuous and reliable, it is necessary to make use of water pipes or common ground wires which connect plate grounds in parallel. O. S. P.

CHEMISTRY.-The possibilities and limitations of the Duclaux method for the estimation of volatile acids. L. J. GILLESPIE and E. H. WALTERS. Journ. Amer. Chem. Soc. 39: 2027-2055. 1917. Direct methods were found for the calculation of the results of analyses by the Duclaux method, and a study was made of the method by means of these methods of calculation. If a mixture can first be shown to contain not more than three volatile acids (of the fatty series) in significant quantities, then a single distillation will serve for the quantitative analysis (and to a certain extent the qualitative analysis) without too great error. The errors for four acids are too great. If four or more acids are present in significant quantities the mixture must be fractionated before applying the calculations into mixtures containing only three acids in significant quantity. The methods of calculations are applicable to distillations made in other ways, for instance to steam distillations at constant volume. In the addendum, an especially simple and rapid graphic method is given for the calculation for the case of three acids. This method has the advantage over the least square method, as any desired weight can be given readily to any observation. L. J. G.

SOIL PHYSICS.-The action of neutral salts on humus, and other experiments on soil acidity. LOUIS J. GILLESPIE and LOUIS E. WISE. Journ. Amer. Chem. Soc. 40:796-813. 1918.

The action of humus on solutions of sodium, potassium, and barium chlorides of different strengths was studied by means of the hydrogen electrode. The measurements showed a large increase of hydrogen-ion concentration as a result of the action. The effect was greatest in the case of barium chloride. Similar effects of smaller magnitude were seen in the action of potassium chloride on true solutions in the absence of humus or undissolved substances; these effects made it unsafe to draw conclusions as to the detailed mechanism of the process in the case of humus.

Some experiments with litmus paper served to make clear the difficulties and limitations of the litmus-paper test as applied to soils and soil extracts. These experiments make it plain that there is no ground for a recent classification of soils which respond in the moist state to blue litmus paper into two types: "truly acid" and otherwise, according to the behavior of the litmus paper toward the aqueous soil extract. Litmus paper cannot be used, without suitable precautions, to arrange soils in the order of their intensities of acidity. There seems to be no reason to assume a mysterious element in soil acidity. L. J. G.

Louis J. GILLESPIE 1917.

SOIL PHYSICS.-Hydrogen-ion concentration measurements of soils of two types: Caribou loam and Washburn loam. and LEWIS A. HURST. Soil Sci. 4: 313-319. The Caribou loam and the Washburn loam from Aroostook County, Maine, possess before cultivation broadly different biological characteristics. Both types are largely devoted to potato culture, the Caribou loam being better adapted to this than the Washburn loam.

Cultivated soils of the Caribou-loam type exhibit, when examined by the colorimetric method, considerably greater hydrogen-ion concentrations than do soils of the Washburn-loam type. The average hydrogen-ion exponent for the Caribou soils was found to be 5.2; that of the Washburn loam, 5.9.

The possibility is indicated that the relative freedom of the Caribou loam from potato scab may be due to its greater hydrogen-ion concentration. L. J. G.

TECHNOLOGY.-Comparative tests of chemical glassware. PERCY H WALKER and F. W. SMITHER. Bur. Stands. Tech. Paper No. 107 Pp. 23. 1918.

Beakers of Kavalier glass, and beakers and flasks of Macbeth Evans, Pyrex, Jena, Nonsol, Fry, and Libbey glasses were tested for chemical composition, coefficient of expansion, refractive index, strain, behavior on repeated evaporation, resistance to heat and mechanical shock, and to solution in a variety of chemical reagents.

No conclusions as to the relative values of the different wares can be drawn from the chemical analyses, though these analyses may be useful by enabling the chemist to choose a glass which will yield no objectional ingredient to the solutions used in any particular piece of work. The coefficient of expansion of all the glasses is low and is unusually so in the Pyrex ware. All the ware shows more or less strain, but it was disappointing to find that no information as to liability to break under sudden changes in temperature or mechanical shock could be obtained by an examination for strain. All the ware tested showed good resistance to repeated evaporation of a salt solution. The Kavalier ware is unsatisfactory as regards solubility in water; all the other wares appear satisfactory in this respect. All the ware is resistant to acids. Kavalier is least resistant to carbonated alkalies, Pyrex more resistant than Kavalier but less resistant than the others. All the glasses are much attacked by evaporating caustic alkalies. The authors are of the opinion that considering all the tests each of the American wares is superior to the Kavalier and equal or superior to the Jena ware. F. W. S.

SCIENTIFIC NEWS AND NOTES

Dr. FRANK BAKER, former superintendent of the Zoological Park and a charter member of the ACADEMY, died at his home, 1901 Biltmore Street, on September 30, 1918, in his seventy-eighth year. Dr. Baker was born at Pulaski, New York, August 22, 1841. He became professor of anatomy at Georgetown University in 1883, and superintendent of the National Zoological Park in 1890, retiring from the superintendency in 1916. He took an active part in the work of the scientific societies, having been secretary of the ACADEMY for thirteen years (18991911), and a member of the Anthropological, Biological, and Medical Societies of Washington. He was president of the Association of American Anatomists in 1897, and editor of the American Anthropologist from 1891 to 1898.

Prof. JOHN T. BATES, formerly professor of Chemical Engineering at Iowa State College, has come to the Bureau of Standards to work on the capacity rating of track scales.

Dr. HEBER D. CURTIS, of Lick Observatory, is engaged in military work relating to optical instruments at the Bureau of Standards.

Col. BRADLEY DEWEY, of the Chemical Warfare Service, has been transferred to the New York headquarters of the Service and is in charge of its gas defense division.

Prof. E. C. FRANKLIN, of Stanford University, California, is on leave of absence and is engaged in research work for the Nitrate Division, Ordnance Department of the Army.

Prof. W. S. FRANKLIN, who has been engaged in investigation work on aeronautical instruments at the Bureau of Standards during the summer, has returned to continue his teaching work at the Massachusetts Institute of Technology.

Prof. R. S. JOHNSTON, formerly in charge of the Structural Materials Laboratory at Lafayette College, has recently joined the staff of the Bureau of Standards.

Miss MCDOWELL, Professor of Physics at Wellesley College, has returned to continue her academic work. She has been engaged in the investigation of crystal detectors for use in radiotelegraphy at the Bureau of Standards during the summer.