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Investigations on the platinum metals VII. Arc spectra of the platinum metals (4500 to 9000 A.D.)
NOTES
FROM
THE
U. S. B U R E A U
INVESTIGATIONS
OF STANDARDS.*
ON T H E PLATINUM METALS.
V I I . ARC SPECTRA OF THE PLATINUM METALS (4Soo TO 9ooo ~.).1
By W. F. Meggars. [ABSTRACT.]
IN OTHER papers of this series mention has been made of the use of the spectrograph to follow the progress of chemical separation of the platinum metals. When materials approximating spectroscopic purity were prepared in this bureau an investigation of the arc spectra was undertaken primarily for the purpose of securing data in the red and adjacent infra-red regions where no data on the emission spectra of the platinum metals existed. Specially sensitized plates were employed to record the spectra with large diffraction gratings, and many hundreds of new lines were measured in the yellow, orange, red, and infra-red regions. Comparison with previous observations in the regions common to the old and to the new measurements showed that the former were incomplete. This led to an extension of the latter to shorter waves, thus including almost all of the visible spectrum, and made it possible to carry out a more extensive comparison of the spectroscopic purity of the materials used by the different observers. New values of wave-lengths and estimated relative intensities are given in six tables as follows : 126o lines for ruthenium (4498.16 to 8867.84 ft.), 572 lines for rhodium (4503.80 to 8615.23 ft.), 172 lines for palladium (4497.66 to 9234.02 ft.), 942 lines for osmium (4500.74 to 8644.8 ft.), 605 lines for iridium (4500.97 to 8426.11 ft.) and 239 lines for platinum (4498.75 to 8762.48 A.). The wave-lengths were measured relative to the secondary standards in the spectrum of the iron arc, and each value is, in general, the mean of from two to ten determinations. The probable error of these values rarely exceeds one one-hundredth of an Angstr6m unit. Six short tables giving lines ascribed to platinum metals by other observers, but not visible on the new spectrograms are subjoined to the major tables, and most of these lines are iden* Communicated by the Director. Scientific Papers, No. 499. Price, ten cents. 687
688
U.S.
BUREAU OF STANDARDS NOTES.
[J. F. I.
tiffed as impurities in the materials at the disposal of the earlier observers. Intercomparison of the results of the new measurements indicate that the metals used in this investigation were exceptionally pure, since even the most intense lines characteristic of each particular element rarely, if ever, appeared in the spectra of the other elements. UNITED
STATES GOVERNMENT MASTER SPECIFICATION FOR BLACK W A T E R P R O O F D R A W I N G INK?
TUE United States Government master specification for black waterproof drawing ink was adopted by the Federal Specifications Board, on December 6, 1924, after it had been submitted to manufacturers and others for criticism. The specification requires that the ink shall be an aqueous suspension of carbon black with the necessary ingredients added to prevent separation or settling out of the pigment and to prevent the growth of mold. The ink must flow freely from an ordinary drawing pen upon tracing cloth or paper. It must dry in ten minutes or less, so that the lines can be rubbed with the finger without smudging. The lines must be intensely black and opaque. Exposure to sunlight or to ultra-violet light must cause no fading (absence of dyes). Washing with water, gasoline, benzene, or carbon tetraehloride must cause no smudging or running of the ink. The ink must show no settling of pigment when allowed to stand undisturbed for two weeks. A sample inoculated with mold spores must show no growth of mold in two weeks. UNITED STATES GOVERNMENT MASTER SPECIFICATION FOR I N D E L I B L E MARKING I N K FOR FABRICS?
THE United States Government master specification for indelible marking ink for fabrics was adopted by the Federal Specifications Board, on December 6, 1924 , after it had been submitted to manufacturers and others for criticism. Two types of ink are recognized: (a) For laundry and household use, and (b) for marking blankets and unsized or unstarched goods. These two types are necessary, because if articles are washed soon after marking, as in laundries, the ink must develop ~Circular No. I96. Price, five cents. aCircular No. I97. Price, five cents.
FROM
THE
U. S. B U R E A U
INVESTIGATIONS
OF STANDARDS.*
ON T H E PLATINUM METALS.
V I I . ARC SPECTRA OF THE PLATINUM METALS (4Soo TO 9ooo ~.).1
By W. F. Meggars. [ABSTRACT.]
IN OTHER papers of this series mention has been made of the use of the spectrograph to follow the progress of chemical separation of the platinum metals. When materials approximating spectroscopic purity were prepared in this bureau an investigation of the arc spectra was undertaken primarily for the purpose of securing data in the red and adjacent infra-red regions where no data on the emission spectra of the platinum metals existed. Specially sensitized plates were employed to record the spectra with large diffraction gratings, and many hundreds of new lines were measured in the yellow, orange, red, and infra-red regions. Comparison with previous observations in the regions common to the old and to the new measurements showed that the former were incomplete. This led to an extension of the latter to shorter waves, thus including almost all of the visible spectrum, and made it possible to carry out a more extensive comparison of the spectroscopic purity of the materials used by the different observers. New values of wave-lengths and estimated relative intensities are given in six tables as follows : 126o lines for ruthenium (4498.16 to 8867.84 ft.), 572 lines for rhodium (4503.80 to 8615.23 ft.), 172 lines for palladium (4497.66 to 9234.02 ft.), 942 lines for osmium (4500.74 to 8644.8 ft.), 605 lines for iridium (4500.97 to 8426.11 ft.) and 239 lines for platinum (4498.75 to 8762.48 A.). The wave-lengths were measured relative to the secondary standards in the spectrum of the iron arc, and each value is, in general, the mean of from two to ten determinations. The probable error of these values rarely exceeds one one-hundredth of an Angstr6m unit. Six short tables giving lines ascribed to platinum metals by other observers, but not visible on the new spectrograms are subjoined to the major tables, and most of these lines are iden* Communicated by the Director. Scientific Papers, No. 499. Price, ten cents. 687
688
U.S.
BUREAU OF STANDARDS NOTES.
[J. F. I.
tiffed as impurities in the materials at the disposal of the earlier observers. Intercomparison of the results of the new measurements indicate that the metals used in this investigation were exceptionally pure, since even the most intense lines characteristic of each particular element rarely, if ever, appeared in the spectra of the other elements. UNITED
STATES GOVERNMENT MASTER SPECIFICATION FOR BLACK W A T E R P R O O F D R A W I N G INK?
TUE United States Government master specification for black waterproof drawing ink was adopted by the Federal Specifications Board, on December 6, 1924, after it had been submitted to manufacturers and others for criticism. The specification requires that the ink shall be an aqueous suspension of carbon black with the necessary ingredients added to prevent separation or settling out of the pigment and to prevent the growth of mold. The ink must flow freely from an ordinary drawing pen upon tracing cloth or paper. It must dry in ten minutes or less, so that the lines can be rubbed with the finger without smudging. The lines must be intensely black and opaque. Exposure to sunlight or to ultra-violet light must cause no fading (absence of dyes). Washing with water, gasoline, benzene, or carbon tetraehloride must cause no smudging or running of the ink. The ink must show no settling of pigment when allowed to stand undisturbed for two weeks. A sample inoculated with mold spores must show no growth of mold in two weeks. UNITED STATES GOVERNMENT MASTER SPECIFICATION FOR I N D E L I B L E MARKING I N K FOR FABRICS?
THE United States Government master specification for indelible marking ink for fabrics was adopted by the Federal Specifications Board, on December 6, 1924 , after it had been submitted to manufacturers and others for criticism. Two types of ink are recognized: (a) For laundry and household use, and (b) for marking blankets and unsized or unstarched goods. These two types are necessary, because if articles are washed soon after marking, as in laundries, the ink must develop ~Circular No. I96. Price, five cents. aCircular No. I97. Price, five cents.