202 Peckham and Linton — Trinidad Pitch. 



The percentage of total bitumen soluble in petroleum ether 

 is shown in the following table : 



No. 21 51-555 



" 22 65-809 



" 23 _ 64-960 



" 24 62-974 



" 25 68-431 



" 26 70-691 



" 16 -.- 66-933 



Nos. 25 and 26 from opposite sides of the lake and very 

 near the border, are the highest in the list and higher than No. 

 9 from the center of the lake, and higher than No. 6 which is 

 the highest commercial lake pitch. The differences and identi- 

 ties of these different groups, as well as between the individual 

 members of the groups, can be readily traced by reference to 

 table No. 2. 



The portion soluble in petroleum ether is called " petrolene." 

 It is a constituent and essential part of the pitch, and embraces 

 all that is most volatile in the pitch, including those etherial 

 or oily fluids that are given off at a temperature below the 

 boiling point of water, and which are found in all specimens 

 from all parts of the deposit (land and lake) that have not 

 been previously heated or decomposed. It is contended that 

 petrolene is the cementitious portion of the pitch, because the 

 remaining portion of the bitumen is solid and insoluble in 

 residuum oil. It might just as well be contended that water is 

 the cementitious principle of glue and that glue has no cement- 

 ing properties because it is not soluble in alcohol. The fact is, 

 that the bitumen of Trinidad pitch consists of asphaltene dis- 

 solved in petrolene and that its cementitiousness is just as 

 much due to one as the other. Sand cannot be cemented with 

 either petrolene or asphaltene alone, neither can wood be 

 cemented with either water or glue alone. The cementitious- 

 ness of the pitch depends upon the amount and quality of the 

 bitumen present. 



"What meaning is intended to be given the word "dry" in 

 connection with pitch is not very clear. It cannot be freedom 

 from moisture, for no specimen of crude pitch is entirely free 

 from water. As found in the deposit, the pitch both outside 

 and inside the lake is saturated with water, and its condition 

 after removal from the deposit depends entirely upon what is 

 done with it. The use of the word " dry " appears to imply 

 that the pitch from outside the lake has lost the whole or a 

 large part of the most volatile oils originally contained in it. 

 No proof whatever has been offered to sustain such assertions. 

 It has been contended that the sun heats the land pitch to 



