It is then pumped to the surface by a single-stroke steam-engine, the annual cost of which is reckoned at £600 sterling.
A grand reservoir has been formed in the fifth level, and into this the water of the lower levels is elevated hy hand-pumps, at an expense of manual labour of 300,000 reals per annum: although the elevation of this general receptacle above the greatest depth is only 110 varas.  It is then pumped to the surface by a single-stroke steam-engine, the annual cost of which is reckoned at £600 sterling.  Besides these motive powers, steam and manual, from j 35 to 40 mules are kept constantly at work, — eight at once, — in drawing up the ore by a rude wheel cap- stan, the friction of which is so great that the animals can only work three hours in the 24.