2So ROCHESTER ACADEMY OF SCIENCE. [MaV 1 4, 



Scattered about the surface of the lake are about thirty small 

 patches of shallow earth covered with bushes and small trees. Mr. 

 McCarth}-. the local manager of the Trinidad Asphalt Company, 

 states that he removed the layer of earth forming one of these islands 

 and that the pitch below then rose to the general level of the lake. 



The Pitch Lake has been the subject of many exaggerations, 

 misrepresentations and romances, not only by mere travelers but by 

 writers of supposed authority. Two of our leading encyclopedias 

 state that its circumference is about three miles, which would give it 

 four times its actual area. In a paper recently read before the 

 American Institute of Mining Engineers the lake is stated to be three 

 miles from the sea, while in fact it is but one, and both elevation and 

 size are incorrectly stated. An official history of the English F^xposi- 

 tion of 1 85 1 states that the Pitch Lake is on the highest land in the 

 island, which is 3,100 feet, while the actual elevation of the lake is 

 but 13S feet. The same authority states that " there is an active sub- 

 marine volcano near the coast," while another writer says that there 

 is " a submarine volcano which at times makes a noise like thunder 

 and emifs naphtha and petroleum." The simple truth is that in one 

 spot near the shore a little oil and gas rise to the surface of the 

 sea. The " noise like thunder " probably refers to the report from 

 the bursting of the bubbles of gas. The few small patches of 

 vegetation upon the lake have been exaggerated to resemble the 

 Thousand Islands of the St. Lawrence. 



The Pitch. 



The asphaltum or " pitch " at the surface is of a brownish-black 

 color and hard to the touch. Even in the hot sun of the tropics it is 

 brittle, except at the centre, so that a pick struck into it will break 

 out pieces of several cubic feet in size. Although brittle it is porous 

 and light so that one man lifts the large pieces into the carts without 

 a.ssistance. After digging down to a depth of three or four feet the 

 pitch is found somewhat softer, and elastic rather than brittle, and 

 the pit is then left to fill up again. Within a day or two the pressure 

 from below will have raised the elastic bottom of the pit to the level 

 of the surrounding surface, but as it is hardened by exposure to the 

 air this lifting is checked and the surface remains nearly level. In 

 this way probably over half a million tons have been taken out within 

 a small area near the margin of the lake without lowering its level. 



The statements of the amount of pitch in the lake, varying from 

 two to four million tons, while mere guesses, seem to me to be under 



