S8. On the Temperature of the Arc.. .C. W. Waidner and G. K. Burgess Estimation of the black-body temperature of positive crater with Le Chatelier, Wanner, and Holborn-Kurlbaum optical pyrometers; variation of temperature with current; review of previous work. Measurements based on Wien-Planck equation for monochromatic radiation. (Sept. 1, 1904.) 16 pp. Price, 5 cents. S9. The Absolute Measurement of Inductance.. ...E. B. Rosa and F. W. Grover The inductances of some standards are measured by the impedance method (using alternating current) in terms of resistance and the frequency of the current. The wave form of the current used is accurately determined and analyzed, and a correction applied for the harmonics present. (Oct. 15, 1904.) 28 pp. Price, 10 cents. SIO. The Absolute Measurement of Capacity. ..E. B. Rosa and F. W. Grover The capacity of standard mica condensers is measured by the Maxwell bridge, in terms of resistance and time. Sources of error are carefully investigated, and results of measurements on a number of condensers given. (Nov. 1, 1904.) 35 pp. Price, 15 cents. SII. Optical Pyrometry. .......C. W. Waidner and G. K. Burgess Review of the laws of radiation and their application to the measurement of high temperatures. Experimental investigation of various types of optical and radiation pyrometers as to methods of calibration, sources of error, order of accuracy, and necessary precautions. Applications to the radiation from platinum and other substances. (Sept. 15, 1904.) 61 pp. Price, 10 cents. S12. On the Theory of the Matthews and the Russell Léonard Photometers for the Measurement Edward P. Hyde The accuracy of these instruments in measuring lamps with various simple polar distribution curves is investigated. The method is given for computing the best arrangement of any given number of mirrors to obtain relative values between lamps having different distribution curves. (Oct. 1, 1904.) 21 pp. S13. The Testing of Clinical Thermometers. ..C. W. Waidner and L. A. Fischer Description of apparatus and methods used in the testing of clinical thermometers. Specifications governing tests. (Nov. 1, 1905.) 15 PP. Price, 15 cents. S14. Measurement of Inductance by Anderson's Method, using Alternating Currents and a Vibration Galvanometer. . . . . . . . . .E. B. Rosa and F. W. Grover This method gives inductance in terms of capacity and resistance. The theory of the method is fully worked out and formulæ derived for the corrections depending on the residual capacities and inductances of the arms of the bridge. Results show that high accuracy is possible. A very convenient and reliable method for a wide range of inductances. (Aug. 15, 1905.) 44 pp. Price, 15 cents. S15. Use of Serpentine in Standards of Inductance.... ....E. B. Rosa and F. W. Grover Serpentine spools are shown to be unsuitable for standards of inductance, as the serpentine is slightly magnetic and its permeability variable. Hence the inductance of the coil depends to some extent on how much current is passing through the coil when it is in use. Marble is nonmagnetic and therefore better. Mahogany spools saturated with paraffin are quite satisfactory. (Aug. 15, 1905.) 12 pp. Price, 10 cents. S16. The Silver Coulometer.. ..K. E. Guthe A critical comparison of different forms of silver coulometer (or voltameter) with an account of some new work with various types and a discussion of the values that have been obtained for the electrochemical equivalent of silver. [Superseded by S285.] (Sept. 1, 1905.) 16 pp. S17. History of the Standard Weights and Measures of the United States. .L. A. Fischer A brief description of the standards of length and mass accepted at different periods by the United States Government. (June 30, 1905.) 17 pp. Price, 10 cents. S18. Wattmeter Methods of Measuring Power Expended upon Condensers and Circuits of Low Power Factor.. Edward B. Rosa The power expended upon a condenser may be measured by a wattmeter, but owing to the small power factor of the current accurate measurements are difficult. Several new null methods are given which permit sensitive instruments to be used and accurate results obtained. (Sept. 1, 1905.) 15 Pp. Price, 10 cents. S19. The Relative Intensities of Metal and Gas Spectra from Electrically Conducting Gases....P. G. Nutting A study of the conditions which determine whether the spectrum of the electrodes shall be brighter or fainter than the spectrum of the surrounding gas. (Aug. 1, 1905.) 18 pp. S20. The Use of White Walls in a Photometric Laboratory. ..Edward P. Hyde If proper black velvet screens are employed on a photometer bench, the leakage of light into the photometer, due to the diffuse reflection from white walls, is shown to be so small as to be negligible. (July 15, 1905.) 4 pp. Price, 5 cents. S21. Influence of Wave Form on the Rate of Integrating ...E. B. Rosa, M. G. Lloyd, and C. E. Reid Experiments on integrating wattmeters show a variation in the rate with changes in the frequency and wave form of the current. (Aug. 15, 1905.) 14 PP. Price, io cents. S22. Detector for Small Alternating Currents and Electrical Waves.. ...L. W. Austin An investigation of the rectifying effects obtained when using copper electrodes in a solution of copper sulphate. (Aug. 1, 1905.) 4 pp. Price, 5 cents. S23. The Positive Charges Carried by the Canal Rays.. .L. W. Austin An experimental demonstration of the positive charges carried by the canal rays. (Aug. 15, 1905.) 3 pp. Price, 5 cents. S24. Radiation from Platinum at High Temperatures.. .G. K. Burgess On a linear relation between the true temperature and the black-body temperature of a radiating substance. (Aug. 15, 1905.) 3 PP. Price, 5 cents. S25. A Five-Thousand Volt Generator Set.......P. G. Nutting A description of a set of 10 small generators giving a direct current of 0.2 ampere at 5000 volts. (Sept. 15, 1905.) 3 pp. Price, 5 cents. S26. Talbot's Law as Applied to the Rotating Sectored Disk... ...Edward P. Hyde The apparent intensity of a source, before which a sectored disk is rotating rapidly, is found to be proportional to the total angular opening of the sectored disk for all angles between 288° and 10°. (Mar. 1, 1906.) Price, 15 cents. S27. A New Determination of the Electromotive Force of Weston and Clark Standard Cells by an Absolute Electrodynamometer.. 32 pp. ...K. E. Guthe An account of the construction and determination of the constant of a Gray absolute electrodynamometer and work done with the same in determining the absolute value of the electromotive force of standard cells, assuming the international ohm. (Later determinations of values for electrical 'standards are given in Coo. See also S171.) (Jan. 15, 1906.) 38 pp. Price, 5 cents. S28. The Gray Absolute Electrodynamometer...Edward B. Rosa A discussion of the theory of the instrument, showing the order of magnitude of certain possible errors and how the dimensions should be taken to conform to the conditions assumed in the formula for the dynamometer. (Jan. 30, 1906.) 16 pp. Price, 5 cents. S29. Construction and Calculation of Absolute Standards of Inductance... .J. G. Coffin A description of two standards of self-inductance and the calculation of their inductance. Two formulas for the calculation of their self-inductances are derived, and several other formulas for the calculation of inductances are given. (Feb. 1, 1906.) 57 pp. Price, 10 cents. S30. An Efficiency Meter for Electric Incandescent Lamps.. ....E. P. Hyde and H. B. Brooks By means of a variable resistance in series with the voltage circuit of a wattmeter and controlled by the position of the photometer screen the wattmeter is made to indicate watts per candle directly. (Mar. 15, 1906.) 16 pp. Price, 10 cents. $31. Calculation of the Self-Inductance of Single-Layer Coils... ..Edward B. Rosa Single layer cylindrical coils are the best form of absolute self-inductances to construct and measure, but the formulas used in their calculation all assume that the current flows in a continuous sheet over the cylindrical surface. In this paper formulas are derived and tables given for calculating two correction terms to be applied to the results obtained from the current sheet formulæ to give the true self-inductance of an actual coil. (Mar. 15, 1906.) 29 pp. Price, 10 cents. S32. Heat Treatment of High-Temperature Mercurial Hobert C. Dickinson Review of previous work. Results of annealing thermometers of different kinds of glass at various temperatures for long periods. Suggestions concerning the proper heat treatment of thermometers, electric annealing furnaces, and the pointing of thermometers to read true gas-scale temperatures. (Apr. 15, 1906.) 36 pp. Price, 10 cents. S33. A New Potentiometer for the Measurement of Electromotive Force and Current.......H. B. Brooks Theory and design of a new instrument for accurate measurements. Consists of a potentiometer with one dial, on which the larger part of the quantity is read off, the remainder being shown by the deflection of a pivoted galvanometer. [Superseded by S172 and S173.] (Mar. 30, 1906.) 17 pp. Price, 10 cents. S34. Spectrum Lines as Light Sources in Polariscopic .Frederick Bates A theoretical investigation of errors incidental to the use of a two-line source. An international standard source is advocated and a measurement made of the ratio of the rotation of quartz for this source and the sodium lines. (May 1, 1906.) II pp. Price, 10 cents. $35. Polarimetric Sensibility and Accuracy. ....... .P. G. Nutting A theoretical investigation of analyzers and light sources for obtaining the highest possible sensibility and accuracy in polarimetry. (May 6, 1906.) 13 pp. $36. On the Platinum Point Electrolytic Detector for Electrical Waves .L. W. Austin An experimental study of the platinum-point electrolytic detector, including the sensibility of the detector for electrical waves from a distance as well as from apparatus in the same laboratory. (Mar. 30, 1906.) 15 pp. Price, 5 cents. $37. Influence of Frequency upon the Self-Inductance of Coils.. .J. G. Coffin A mathematical discussion of the variation of the self-inductance of a single layer coil with the frequency of the current. (Mar. 30, 1906.) 23 pp. Price, 10 cents. S38. Experiments on the Heusler Magnetic Alloys. ..K. E. Guthe and L. W. Austin Experimental study of seven samples of Heusler magnetic alloys, which are made from nonmagnetic metals. The magnetic properties of these samples are given in tables and curves. (Mar. 30, 1906.) 21 pp. Price, IO cents. S39. A Pocket Spectrophotometer.. .P. G. Nutting A description of a modified spectrophotometer on the plan of a pocket spectroscope. (July 15, 1906.) 3 pp. Price, 5 cents. S40. Preliminary Measurements on Temperature and .....C. W. Waidner and G. K. Burgess Measurement of temperature and selective radiation of filaments of tantalum, tungsten, and carbon. On the melting point of tungsten. (Sept. 30, 1906.) 11 pp. Price, 5 cents. S41. Revision of the Formulæ of Weinstein and Stefan for the Mutual Inductance of Coaxial Coils.. .....Edward B. Rosa Weinstein's formula is accurate only for coils at distances large as compared with the cross section, and Stefan's only at near distances. Weinstein's is revised and corrected, and a new formula derived to replace Stefan's, the two agreeing closely and giving very accurate results. (Sept. 1, 1906.) 27 pp. Price, 5 cents. S42. The Mutual Inductance of Two Circular Coaxial ..E. B. Rosa and Louis Cohen Various formulas for calculating the mutual inductance of coaxial circles and coaxial circular coils of rectangular section are investigated, and some new formulas derived. The best formulas for particular cases are indicated; it is shown where some formulas fail, and numerous examples are given to illustrate the formulas. (Sept. 1, 1906.) 56 pp. Price, 10 cents. $43. On the Determination of the Mean Horizontal Intensity of Incandescent Lamps by the Rotating Lamp Method...E. P. Hyde and F. E. Cady A study of the errors incident to this method, due (1) to the distortion of the filament on rotation, and (2) to the inability of the eye to estimate accurately a badly flickering illumination. By the use of a single stationary mirror accurate measurements of mean horizontal candlepower can be made even with badly flickering lamps. (Sept. 1, 1906.) 23 PP. Price, 10 cents. S44. Purity and Intensity of Monochromatic Light Sources.. ....P. G. Nutting A mathematical treatment of spectral impurity and center of luminosity, with the results of an investigation of available light sources. (Sept. 1, 1907.) 18 pp. Price, 5 cents. $45. Radiometric Investigations of Infra-Red Absorp tion and Reflection Spectra.. .......W. W. Coblentz The fact that certain groups of elements have characteristic absorption bands is applied to substances containing water of constitution and water of crystallization. It is shown that in the former the oxygen and hydrogen atoms are not united, while in the latter they are united, giving the characteristic absorption spectrum of water. The second part of the paper gives the reflecting power of various metals, not investigated heretofore, and of various minerals, especially of the silicates. (Sept. 1, 1907.) 22 pp. Price, 10 cents. $46. A Vacuum Radiomicrometer.. .W. W. Coblentz This is a modification of the instrument devised by Boys, and includes also a combination of the Nichols radiometer with the radiomicrometer. The paper indicates directions in which further improvements are possible. (Sept. 15, 1907.) 5 pp. Price, 5 cents. $47. On the Geometrical Mean Distances of Rectangular Areas and the Calculation of Self-Inductance ....Edward B. Rosa It is shown in this paper that Maxwell's correction term in the formula for the self-inductance of a coil of wire, depending on the difference in the mutual inductances of round and square wires, is wrong, and Stefan's only approximately correct. The formulas are fully worked out by the method of geometrical mean distances and verified by other methods, and the true correction term for different cases is calculated. Further use of the method of geometrical mean distances in the calculation of inductances is indicated. (Nov. 1, 1906.) 41 pp. Price, 10 cents. S48. The Compensated Two-Circuit Electrodynamom eter... ..Edward B. Rosa The instrument is used especially for the accurate measurement of alternating current and power. The theory of the instrument is given and a compensation provided so that when calibrated by means of direct current it is correct for alternating currents of different frequencies and any magnitude. (Nov. 1, 1906.) 16 pp. Price, 10 cents. S49. Complete Form of Fechner's Law.. .P. G. Nutting A mathematical investigation of the quantitative relation between luminous intensity and visual sensation based on König's data on least perceptible increment. (Dec. 15, 1906.) 6 pp. Price, 5 cents. S50. A Comparison of the Unit of Luminous Intensity of the United States with those of Germany, England, and France.... ...Edward P. Hyde A number of seasoned incandescent lamps were carried abroad and measured in authoritative laboratories in the three countries named. The ratios of the units obtained through them are compared with the ratios generally accepted and with those obtained in other recent investigations. (Jan. 15, 1907.) 16 pp. |