COSTA RICA. 263 



those of Quebrada-honda at Trevithick's mill, and then 40 tons 

 of water per minute could be delivered in the dry season." 



Extracts from a report by Trevithick and Gerard in 



1827:- 



" This map consists of several distinct parts. The middle 

 part shows the mining district, the present dimensions of which 

 are small, the length being hardly four miles, breadth from 

 two to three, and the superficial extent from eight to ten miles. 

 The upper part of the plan is a section of the north ridge, 

 called Quebrada-honda, and shows the line of the proposed 

 adits. The lower part in like manner exhibits the south ridge, 

 called Coralillo. The map further shows the inclination or 

 gradual fall of the ground along the valley, and of the streams 

 by which the mills are driven. 



"The canal is likewise shown 5000 yards in length, by 

 which the rivers of Machuca would be brought to join that of 

 Quebrada-honda. 



" Castro's mine is situated on the southern ridge, and was the 

 first mine worked to any extent. There the veins are very 

 large ; in fact, from the manner in which a number of horizontal 

 veins are seen falling into the perpendicular or master vein, the 

 great body of the mountain would appear to consist of lodes. 

 This mass of ore is in general rich. It has been worked open 

 to the surface, somewhat like a quarry, so that it is not difficult 

 to calculate in cubic feet the quantity that has been excavated. 

 The mine is supposed to have yielded in the course of the last 

 six years gold to the value of 40,OOOZ., and by measuring the 

 excavations it would appear that this amounts to, on an average, 

 one ounce of fine gold to every ten or twelve quintals of ore. 

 In 1821 the existence of silver was only imagined. In 1823 it 

 was fully ascertained. Ever since 1824 it has constituted a 

 small but constant portion of the produce of Quebrada-honda, 

 and in 1827 it was decidedly evinced in Coralillo. The dis- 

 covery of gold in Coralillo led them to work in Quebrada-honda, 

 where they found both gold and silver, and the discovery of 

 silver in Quebrada-honda, by strengthening the expectation of 

 it in Coralillo, led in its turn to the discovery of silver there. 



T 2 



