230 BELL SYSTEM TECHNICAL JOURNAL 



are confined to an examination of the composition of the Hquid and 

 t^aseous products. Among exceptions to this generalization may be 

 mentioned the interest in coke, carbon black, and charcoal. Even in 

 these cases the physical properties rather than the chemical composi- 

 tion are regarded as the factors which determine their suitability for 

 specific uses. However, in an earlier paper it was pointed out that 

 certain physical properties of a group of charcoals were rather simply 

 related to the per cent hydrogen which was contained in them as de- 

 termined by ultimate analysis. This group of charcoals was prepared 

 in a gas-fired furnace from a single, specially-selected lot of anthracite 

 coal. As stated in this earlier paper, careful consideration of the 

 commercial records taken at the time of preparation indicated that 

 the hydrogen content was probably determined by the maximum 

 temperature to which the samples were heated during their preparation. 

 The hydrogen contents ranged from 0.21 to 0.53%, while the probable 

 range of maximum temperature was 900° to 1200°. The presence of 

 hydrogen in these charcoals was shown to be consistent with a point 

 of view that so-called "amorphous" carbons are hydrocarbons of low 

 hydrogen content built up of polymerized residues from the thermal 

 decomposition of hydrocarbons of greater hydrogen content. Since 

 the significance of the hydrogen content of charcoals has been generally 

 overlooked, the present study was undertaken in order to evaluate the 

 factors which may ordinarily be varied in the preparation of charcoals 

 for various purposes. The factors which were independently varied in 

 this study were the maximum temperature, the time of heating, the 

 atmosphere surrounding the sample during heating and the raw 

 material. To a limited extent the effect of previous heat treatment 

 was also determined. A later paper will give the results of the study of 

 the correlation of hydrogen content and some adsorptive properties of 

 charcoals prepared under carefully controlled conditions. 



Btginnings of TelepJiovyJ Frederick Leland Rhodes, Outside 

 Plant Development Engineer, Department of Development and Re- 

 search, American Telephone and Telegraph Company. 



It is only within the past decade or so that science and business have 

 become subjects for literature. Somehow these great phases of human 

 endeavor have been sadly neglected in the literary world until very 

 recently, and now it seems as though, conscious of the lack of good 

 literature in these fields, engineers, scientists and business executives 

 are making up for lost time. Frederick Leland Rhodes has written a 

 new book which undoubtedly will be of great assistance to those in the 



' Harper & Brothers, New York and London, 1929. 



