XXXVI.—The Absorption of Light by Inorganic Salts. No. I.: Aqueous Solutions of Cobalt Salts in the Infra-Red

1912 ◽  
Vol 31 ◽  
pp. 521-529 ◽  
Author(s):  
R. A. Houstoun
Keyword(s):  
Aqueous Solutions ◽  
Present Article ◽  
Extinction Coefficient ◽  
Accurate Determination ◽  
Visible Spectrum ◽  
Inorganic Salts ◽  
Absorption Of Light ◽  
Infra Red ◽  
Molecular Extinction Coefficient

The present article is intended to be the first of a series on the absorption of light by solutions of inorganic salts of different elements. With a few scattered exceptions all the work hitherto done on the absorption spectra of inorganic salts has been merely qualitative and has been confined to the visible spectrum. Kayser in his Spectroscopie, vol. iii. p. 45, states that in this field there is work for years and for numerous observers. E. C. C. Baly states in his Spectroscopy, p. 407, that not much is known about the absorption of light in inorganic salts. Merely for its own sake, then, an accurate determination of the molecular extinction coefficient for as many salts under as many different conditions of temperature and concentration, and for as many wave-lengths as possible, would be very valuable.

XXXVII.—The Absorption of Light by Inorganic Salts. No. II.: Aqueous Solutions of Cobalt Salts in the Visible Spectrum

1912 ◽  
Vol 31 ◽  
pp. 530-537 ◽  
Author(s):  
R. A. Houstoun ◽  
Alex. R. Brown
Keyword(s):  
Aqueous Solutions ◽  
Visible Spectrum ◽  
Inorganic Salts ◽  
Sulphate Chloride ◽  
Absorption Of Light ◽  
Infra Red

As in the case of the work in the infra-red, the salts experimented on were the nitrate, sulphate, chloride, bromide, fluoride, and iodide, and they were obtained from Kahlbaum. Very little trouble was experienced with the sulphate, nitrate, and chloride. The salts were supplied as CoSo47H2O, Co(NO3)26H2O, CoCl26H2O. The fluoride was a pinkish powder sparingly soluble in water. It dissolved with formation of insoluble oxyfluoride which seemed to increase on standing. By heating the salt and driving off the water of crystallisation, it was found to be Cof22H2O. The iodide was an extremely deliquescent green powder. A slight insoluble chocolate-coloured residue remained in the solution and was filtered off. By heating the salt it was found to have the composition CoI2H2O. The bromide consisted of very deliquescent crimson lumps, and was found to have the composition CoBr26H2O.

XXXVIII.—The Absorption of Light by Inorganic Salts. No. III.: Aqueous Solutions of Nickel Salts in the Visible Spectrum and the Infra-Red

1912 ◽  
Vol 31 ◽  
pp. 538-546 ◽  
Author(s):  
R. A. Houstoun
Keyword(s):  
Aqueous Solutions ◽  
Visible Spectrum ◽  
Inorganic Salts ◽  
Cotton Wool ◽  
Absorption Of Light ◽  
Infra Red

The methods and the apparatus were the same as in the two previous articles of the series and hence need not be described, the only change being in connection with the galvanometer. Previously it had rested on the table, but when half the results in the infra-red recorded in this paper were obtained, the arrangement was changed; it was suspended by three iron wires each about one and a half metres long from a bracket in the wall and hung with its three levelling screws clearing the table by about one centimetre. Between the table and levelling screws were placed loose wads of cotton wool for the purpose of damping any vibrations that might arise. With this arrangement the zero is very much less sensitive to vibration. With the lamp and scale at one and a half metres—the distance at which they are ordinarily used now–vibrations of the laboratory rarely cause the zero to move mm. either way.

VII.—The Absorption of Light by Inorganic Salts. No. V.: Copper and the Alkali Metals

1913 ◽  
Vol 32 ◽  
pp. 40-49 ◽  
Author(s):  
R. A. Houstoun
Keyword(s):  
Alkali Metals ◽  
Periodic Group ◽  
Visible Spectrum ◽  
Ultra Violet ◽  
Inorganic Salts ◽  
Absorption Of Light ◽  
Infra Red ◽  
New Apparatus

The research described in this article was undertaken with the double purpose of testing new apparatus and of making a rapid survey of the absorption of light by salts of the first periodic group.The results described in the previous articles were obtained by three separate methods, viz. the thermopile in the infra-red, the spectrophotometer in the visible spectrum, and the photographic spectrophotometer in the ultra-violet. It would be a great simplification if the same apparatus could be used throughout the whole spectrum, and I therefore first of all devoted my attention to seeing if this were practicable.

IV.—The Absorption of Light by Inorganic Salts. No. VIII. Alcoholic Solutions of Copper, Cobalt, and Nickel Salts in the Ultra-Violet

1914 ◽  
Vol 33 ◽  
pp. 44-48
Author(s):  
Alex. R. Brown
Keyword(s):  
Visible Spectrum ◽  
Ultra Violet ◽  
Inorganic Salts ◽  
Quantitative Measurements ◽  
Absorption Of Light ◽  
Cobalt And Nickel

The salts experimented on in this research were the chlorides, bromides, nitrates, and sulphates of copper, cobalt, and nickel. They were obtained from Kahlbaum. Jones and his co-workers have already investigated qualitatively the absorption of alcoholic solutions of some of these salts. Also quantitative measurements of the absorption at a few points in the visible spectrum have been made by Vaillant for some of the hydrated salts. In the present case solutions of the anhydrous salts were examined.

Disubstituted hydroxamic acids and the determination of vanadium

1968 ◽  
Vol 46 (2) ◽  
pp. 327-330 ◽  
Author(s):  
R. M. Cassidy ◽  
D. E. Ryan
Keyword(s):  
Extinction Coefficient ◽  
Metal Chelate ◽  
Visible Region ◽  
Hydroxamic Acids ◽  
Molecular Extinction Coefficient ◽  
Sensitivity Increase ◽  
Chelate Rings

A number of disubstituted hydroxamic acids were investigated as possible replacements for benzoylphenylhydroxylamine in the determination of vanadium; none is superior. At 378 mμ., p-phenylazobenzoylphenylhydroxylamine shows a marked sensitivity increase but selectivity is poor. In the visible region, there is an increase in molecular extinction coefficient as the reagent π system is extended; how ever, complete coplanarity of the aromatic and metal chelate rings is not possible and the increase is not large enough to be of much practical value.

XXXIX.—The Absorption of Light by Inorganic Salts. No. IV.: Aqueous Solutions of Cobalt and Nickel Salts in the Ultraviolet

1912 ◽  
Vol 31 ◽  
pp. 547-558 ◽  
Author(s):  
R. A. Houstoun ◽  
John S. Anderson
Keyword(s):  
Ultra Violet ◽  
Practical Method ◽  
Inorganic Salts ◽  
Metal Electrodes ◽  
Violet Light ◽  
Limited Success ◽  
Absorption Of Light ◽  
Infra Red ◽  
Enormous Amount ◽  
Cobalt And Nickel

In Kayser's Spectroscopie, vol. iii. pp. 45–49, an account is given of all the different methods that have hitherto been employed for photometry in the ultra-violet part of the spectrum. Photography, phosphorescent plates, selenium cells, and the ionising effect of ultra-violet light have all been used, but with limited success, and Professor Kayser considers that the only really practical method is that which has been recently introduced by Pfluger. Pfliiger has discovered that there is relatively an enormous amount of energy in the ultra-violet spectrum of the electric spark produced by the discharge of a condenser between metal electrodes. He therefore uses the electric spark as a source, and takes the deflections with a thermopile and galvanometer, just as in the infra-red. He finds the deflections to be wonderfully steady, considering the inconstant nature of the spark.

The Foundation and Early Development of the Nautical Almanac

1965 ◽  
Vol 18 (4) ◽  
pp. 391-401 ◽  
Author(s):  
Eric G. Forbes
Keyword(s):  
Eighteenth Century ◽  
Present Article ◽  
Early Development ◽  
Accurate Determination ◽  
Practical Possibility ◽  
The World ◽  
Nevil Maskelyne ◽  
Nautical Almanac ◽  
Different Parts

Soon after the middle of the eighteenth century, improvements in the design and construction of astronomical and nautical instruments, coupled with the increased accuracy of tables of the Moon's motion, at last made the accurate determination of longitude at sea by lunar distance a practical possibility. The Astronomer Royal, Nevil Maskelyne, was quick to appreciate the importance of publishing the calculated solar and lunar ephemerides, together with other relevant tables and explanations, in the form of a Nautical Almanac, which was first printed under his supervision in 1766 and immediately distributed to mariners in different parts of the world. The present article is concerned with the circumstances relating to the origin and development of this publication during the first fifty years of its existence.

A High Sensitivity Digital Raman Difference Spectrometer for Studies on Solutions of Biological Molecules with On-Line Computer Control of Data Acquisition and Reduction

1976 ◽  
Vol 30 (2) ◽  
pp. 168-179 ◽  
Author(s):  
Ray W. Chrisman ◽  
Jim C. English ◽  
R. Stuart Tobias
Keyword(s):  
Aqueous Solutions ◽  
Computer Control ◽  
Visible Spectrum ◽  
High Sensitivity ◽  
Biological Molecules ◽  
Difference Spectra ◽  
On Line ◽  
Dilute Aqueous Solutions ◽  
Good Signal

The design and construction of a computer-controlled Raman spectrophotometer for the determination of difference spectra among up to four samples is described. The advantages of control by a minicomputer compared to a microcomputer or a hard wired controller are discussed. Conditions for the attainment of good signal/noise ratios with aqueous solutions of nucleotides in the 1 to 25 m M range are examined for the case of excitation in the visible spectrum to minimize radiation damage. Applications to studies of dilute aqueous solutions of biological molecules are discussed. The interactions of small molecules with bio-polymers, particularly, are examined.

scholarly journals A METHOD FOR THE DETERMINATION OF THE BLUE DYE T-1824 IN PLASMA

1943 ◽  
Vol 77 (5) ◽  
pp. 421-434 ◽  
Author(s):  
Robert Allan Phillips
Keyword(s):  
Alkaline Solution ◽  
Extinction Coefficient ◽  
Blue Dye ◽  
Absorption Of Light ◽  
Before And After ◽  
Dye Absorption

A method for the estimation of the concentration of the blue dye, T-1824, in plasma has been developed. The method is based on the fact that the dye can be reduced to a colorless compound by Na2S2O4, in alkaline solution. The extinction coefficient is determined under specified conditions before and after reduction of the dye. Under the conditions employed hemoglobin does not interfere, even if partly present as HbCO or as methemoglobin; the absorption of light by the hemoglobin is the same before and after reduction of the dye. Absorption of light by suspended lipids and plasma pigments is also unaltered by the Na2S2O4. Hence variations from sample to sample in hemolysis or degree of lipemia do not affect the accuracy with which T-1824 is determined.

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