Graphite, Plumbago or Red Lead. 47 



Pennsylvania ; although no analysis has been made of the former. 

 But carbon is less combustible than hydrogen. Yet I can hardly be- 

 lieve, that a coal, which contains probably not less than 90 per cen- 

 tum of carbon, should not be employed, in some way or other, as val- 

 uable fuel. 



The formation which I have denominated gray wacke, and which 

 contains the anthracite in Rhode Island, extends northerly in interrup- 

 ted patches, nearly across the whole of Massachusetts; as may be 

 seen on the Map. The most southern patch, embraces nearly the 

 whole of Bristol and part of Plymouth county ; the second branches 

 from the first at Wrentham, and extends to Dedham ; the third in- 

 cludes several towns in the vicinity of Boston ; and the fourth is in 

 Rowley and Newbury in Essex county. I know of no reason, why one 

 part of this formation should contain anthracite rather than another ; 

 and hence we may reasonably look for it in any part of the gray wacke 

 formation, exhibited on the Map. The transition mica slate containing 

 the Worcester anthracite, occupies, as the Map will show, a large por- 

 tion of the northeastern part of the state ; and it would not be strange if 

 other beds ofthat mineral should be found in it. 



Graphite, Plumbago, or Black Lead. 



This substance has the color of lead, leaves a trace like that metal 

 upon paper, and bears the common name, black lead ; but it contains no 

 lead. It is composed of above 90 per centum of carbon, and the rest is 

 iron and earthy matter. Hence it differs but little from some varieties 

 of anthracite. It seems indeed to be t-he form in which carbon occurs 

 in the oldest of the rocks. In Massachusetts it exists in gneiss, at 

 the most important locality, which is in Sturbridge. It there occurs 

 in a bed, varying in width from an inch to about two feet, and trace- 

 able along the surface, nearly one hundred rods. A number of years; 

 ago this bed was opened ; and several tons of the graphite obtained. 

 It was then abandoned ; but within a few years the exploration has; 

 been recommenced, and already more than a hundred tons have been 

 obtained. In some places the excavation is 60 or 70 feet deep.. 

 The quality of the graphite is excellent and would not suffer by com- 

 parison, with almost any in the world. To what extent it may be ob- 

 tained, it is not possible at present to determine. The fact, that the 

 bed descends, almost perpendicularly, into the earth, is rather unfavor- 

 able to the miner. Yet, as it is found upon elevated ground, the 

 mine can be conveniently drained by lateral cuts or adits to a consid- 



