Basing the "higher heat" value of gasoline as to weight and 

 volume on 100%, it is to be noted from this table that the value 

 of alcohol is 60.8% and 68.5 respectively, which is to say that 

 on the same basis alcohol is 39.2% lower than gasoline by weight 

 and 31.5% lower by volume than gasoline. It is further to be noted 

 that the "lower heat value" for alcohol is 59.2% by weight and 

 66.4% by volume of the "lower heal* value" of gasoline. Atten- 

 tion is called to the fact that unless a greater thermal efficiency 

 can be secured in the use of alcohol in lamps and internal com- 

 bustion engines, its consumption must necessarily be much 

 greater. 



The reason for the difference in heat values of gasoline and 

 alcohol may be explained quite easily from a chemical standpoint. 

 Gasoline is composed almost entirely of bodies belonging to an 

 important series of compounds known as the paraffine series. 

 This series has many derivatives such as its nitrogen, sulphur, 

 and oxygen derivatives. The alcohols are a class of the oxyger. 

 derivatives of which ethyl alcohol is a member. In other words 

 the alcohols may be said to represent the first stage of oxidation 

 of the corresponding members of the paraffire series. 



Composition of Fuels.* The crude petroleums of the United 

 States are largely made up of bodies of different densities com- 

 posing the paraffine series. All these oils contain twice as much 

 hydrogen plus two p^rts, as carbon and are represented by the 

 general formula G n H, n + z where n may be any number from 

 i to 32. The lower values of n represent gases while the higher 

 values represent successively gasoline, napthas, kerosene, heavier 

 illuminating oils, lubricating oils of different grades and finally 

 paraffine. It is stated by good authority that gasoline often con- 

 tains bodies differing in formula from C 5 H 12 to C 8 H 18 The 

 heavier ones or those of higher carbon content were formerly sold 

 as napthas, but under present market demands are included in 

 gasoline ; in fact most of the gasoline used in these tests was of 

 such density as corresponds toC 8 H 18 



The same series, with the addition of one part of oxygen, 

 represents the class of derivatives known as the alcohols the gen- 

 eral formula for which is C n H 2n f 2 O. The first in the class is 

 wood or methyl alcohol C H 4 O or as it is more often written 

 C H 3 O H, grain or ethyl alcohol is next C, H, O H. followed 

 by others the first few of which are usually distilled in small 

 amounts with grain alcohol. The heaviest of the class is bee's 

 wax C 30 H 61 O H. 



*The authors wish to acknowledge valuable assistance in the way of sugges- 

 tions and the loan of apparatus by Professors L. G. iMichael and W. F. Coover, 

 Agricultural Chemists at Iowa State College. 



