Mat 9, 1913] 



SCIENCE 



713 



erature on petroleum has been partly sum- 

 marized by Redwood," by Richardson^ and by 

 Clarke.' It was evidently the plan of the au- 

 thors of " Das Erdol " to include all that is 

 known concerning petroleum, and one does 

 not proceed far in the perusal of this vol- 

 ume to be convinced that their object will be 

 well attained. It is safe to assert that this 

 work will be found readily accessible for con- 

 venient consultation by the investigator, ex- 

 perimenter and refiner, for it will be an indis- 

 pensable aid to every one interested in this 

 subject. 



This volume is devoted to the varieties of 

 bitumen as a generic term for solids and liq- 

 uids, and to natural gas, their composition, 

 genetics, occurrence, chemical and physical 

 properties, optical characters, heats of combus- 

 tion, fractional distillation and lubrication. 

 But much the larger space is devoted to the 

 composition of petroleum and its products, 

 with a complete review of the series of hydro- 

 carbons that have been found in petroleum, 

 and the structural relations of the various 

 series on the basis of the most recent classifi- 

 cation of the hydrocarbons. 



There is a full discussion of all investiga- 

 tions of petroleum from the beginning, and 

 large space is given to the work on American 

 petroleum. The identity of the naphtenes first 

 discovered by Markownikow in Russian pe- 

 troleum with the same constituents in Amer- 

 ican petroleum, and with the more recently 

 synthetically prepared cyclo-hydrocarbons, is 

 fully set forth. 



It is gratifying to observe that the proof of 

 the absence in any appreciable qualities of 

 ethylene hydrocarbons, especially from Ameri- 

 can petroleum, is comprehensively presented, 

 for the erroneous statements on this subject 

 in all works on petroleum have been grossly 

 misleading. An interesting resume is given 

 of the facts and theories relating to the nat- 

 ural formation of petroleum from a chemical 



' ' ' Petroleum and its Products. ' ' 



'"The Modern Asphalt Pavement," J. Wiley & 



'"Data of Geo-chemistry, 

 Survey, 1908. 



TJ. S. Geological 



point of view. The behavior of petroleum and 

 its products towards reagents, the action of 

 atmospheric agencies, oxygen and ozone, as 

 well as light, are critically considered. 



The complete description of crude petroleum 

 from all well-known fields, including its com- 

 position and properties, will be serviceable to 

 the prospector and the refiner. Pyrogenic de- 

 composition under various conditions, with 

 what is known to the refiner as cracking, re- 

 ceives careful attention, as does also such sub- 

 jects as absorption, capillarity, conditions and 

 limits of explosion, and physiological effects. 

 Considerable space is devoted to lubrication 

 and the eiSciency of lubricants. The theory 

 of viscosity and the laws and practical opera- 

 tion of frictional testing machines are pre- 

 sented, with comprehensive tables and ordi- 

 nate diagrams of the relative and absolute 

 viscosity of the hydrocarbons, both paraffine 

 and aromatic. 



Reference is made to the lack of efiiciency 

 of dry lubricants and attention is called to the 

 great advantage of a combination of an oil 

 lubricant with graphite in such form that it 

 reduces very materially the coefficient of fric- 

 tion by saturating the bearing with graphite, 

 and at the same time forming a coherent film. 

 It is explained that the difficulty of obtaining 

 graphite in a sufficiently fine condition has 

 been overcome by the colloidal graphite re- 

 cently discovered by Dr. Edw. G. Acheson 

 which is used in the form of oildag, a sus- 

 pension of colloidal graphite in a suitable oil 

 or in the form of aquadag, a suspension in 

 water. Diagrams and results of frictional 

 tests on the Carpenter machine are presented, 

 from which the following interesting conclu- 

 sions are translated. 



These experiments confirm a,lso the theory that 

 a proper use of the combined oil-graphite lubri- 

 cant is in high degree profitable. Besides the re- 

 duction of the coefficient of friction which is 

 important from an economical point of view, a 

 material saving in wear of bearing surfaces and 

 of the lubricant required are other essential fea- 

 tures in reducing the operating cost. Then, too, 

 the factor of safety in operating is essentially 

 larger and the danger of overloading much less 

 than with lubricants containing no oildag. These 



