render the rainy season more severe in the mining district than in the plains. The greatest inconvenience was from the snakes, which in those solitary jungles, now first invaded by man, are very numerous and many of them venomous. Provisions are cheap and excellent. In short, there is but one fault I find with the country, and it is a great one, I mean the frequency of earthquakes. "J. M. GERARD." MEM. IN MR. GERARD'S WRITING. "_Illustrations of the Map._ "Though the plans and sections explain themselves, a few observations will not be misplaced. The deep adit for the Coralillo would be 600 yards, that for Quebrada-honda 400 yards, and besides serving as drains would form admirable roads for conveying the ores into the vale where the stamps must be erected. "The veins would be worked upward from the adits, and thus no expense would be incurred for ages to come in lifting either water, ore, or rubbish to the surface. Padre Arias Mine is an exception, requiring a powerful water-wheel, or an hydraulic pressure-engine, for which there is a fine fall of water of 135 feet. The mines in Quebrada-honda are those in which an interest has been procured. Captain Trevithick has an interest in the mine of Coralillo; the great watercourse is also his. "It will be seen by the plan that there are 75 fathoms fall to the point where his present mill is situated, and other 75 fathoms to the junction of the rivers of Quebrada-honda and Machuca. The whole length does not amount to two miles, within which it is estimated that sufficient power may be commanded to stamp 500,000 of quintals annually. To bring it up to that pitch, the waters of Machuca must be brought to join 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.