42 Chemistry and Physics 



A number of representative salts have also been studied in mixed solvents con- 

 taining formamid. A comparative study was made of the results obtained in this 

 and in earlier investigations on aqueous solutions. 



The limiting conductivities of the sodium salts of the organic acids in abso- 

 lute ethyl alcohol have been studied and a method applied to the calculation of 

 the dissociation both of the acids and their salts in this solvent. The relative dis- 

 sociating power and chemical activity of free and combined water have been 

 more extensively investigated and the tentative conclusions drawn in a previous 

 report (see Publication No. 230) have been confirmed. 



No. 71. UHLER, H. S., and R. W. WOOD. Atlas of Absorption Spectra. Quarto, 



59 pages, 26 plates, 7 figures. Published 1907. Price $1.50. 

 The selective absorptions for light of about 180 aqueous solutions of the aniline 

 dyes are described in the text as well as presented graphically by the photographic 

 reproductions of the plates. The dispersion used was practically normal, and the 

 region of the spectrum investigated extended from 0.20^- to about 0.65 /A. A few 

 inorganic substances possessing absorption bands of especial interest were also 

 studied and the results incorporated in the text and plates. Complete data are given, 

 so that the absorption bands can be readily reproduced quantitatively whenever 

 absorbing screens are needed for photographic or other purposes. 



No. 35. COBLENTZ, W. W. Investigations of Infra-red Spectra. Part I. Infra-red 

 Absorption Spectra. Part II. Infra-red Emission Spectra. Octavo, 

 331 pages, 152 text figures. Published 1905. Price $1.75. 



A spectroradiometric investigation of the most important groups of chemically 

 related compounds to determine what effect certain groups of atoms have upon the 

 transmission of radiant energy. Part I describes the absorption spectra of 135 

 substances, including solids, liquids, and gases, many being organic compounds. The 

 observations extend from the visible spectrum to wave-length 0.015 mm. in the 

 infra-red. Many absorption bands were identified with certain groups of atoms, 

 e. g., with CHs, NH4, NO2. OH, NCS, etc. Five appendices are added, which deal 

 with subsidiary problems, such as radiometers, absorption of solids in solution, etc. 



Part II gives the results of a radiometric investigation of the emission spectra 

 of various metals in the carbon arc and of gases in a vacuum tube. 



No. 65. COBLENTZ, W. W. Investigations of Infra-red Spectra. Part III. Infra-red 

 Transmission Spectra. Part IV. Infra-red Reflection Spectra. Octavo, 

 128 pages, 93 text figures. Published 1906. Price $1.00. 



A continuation of the investigation described in No. 35. In Part III the results 

 obtained in Part I are applied to gain information with regard to the molecular struc- 

 ture of minerals containing oxygen and hydrogen in the form of "water of crystal- 

 lization" and of "water of constitution." It is shown that the spectra of minerals 

 containing "water of crystallization" have absorption bands identical with those of 

 water, while "water of constitution" shows no such bands. 



In Part IV are described the reflection spectra of various minerals, such as, for 

 example, sulphides, sulphates, silicates; also solutions of these substances and metals 

 not heretofore examined. 



Five appendices are added, in which are described the emission spectrum of 

 carbon disulphide, a new radiomicrometer, methods of blowing quartz fibers, and a 

 discussion of the possibility of the observed radiation from the moon being due, in 

 part, to selectively reflected solar energy. 



No. 97. COBLENTZ, W. W. Supplementary Investigations of Infra-red Spectra. 

 Part V . Infra-red Reflection Spectra. Part VI. Infra-red Transmission 

 Spectra. Part VII. Infra-red Emission Spectra. Octavo, 183 pages, 

 107 text figures. Published 1908. Price $1.25. 



This is an extension of the investigations which are described in Nos. 35 and 65. 

 Part V gives the reflection spectra of various substances, including sulphides, oxides, 

 carbonates, and silicates not previously obtainable. In the sulphides and carbonates 

 the long-sought-for shift of the maximum of the reflection or absorption band with 

 change in atomic weight of the basic element (which is joined to the CO2 or 



