9 



strength, necessitate the employment of children with a load of 3-6 quaninie 

 (ahout 25-50 lbs). 



The use of any machinery whatsoever as aid, the windlass for instance or the 

 whim is only an acquisition of modern times. 



DEAINAGE. 



As to the drainage, it has already been remarked, that its miserable condi- 

 tion very much aggravates the difficulty of working the mines, aud has often 

 been the cause of their abandonment. 



Almost the only instrument for lifting the water to the water-adit, is a hand- 

 pump. It consists in a prismatic, wooden box, open at top and at bottom, about 

 3,5™ long and about 12 centimeters square wide inside. The lower part of the 

 box is furnished with a clack-valve, that opens upwards. In this box a valve- 

 piston of corresponding size, with leather packing, moves up and down by aid 

 of a piston rod, worked directly with the baud. 



As for the haulage, so also for the pumps, vertical pits are avoided, and slopes 

 are used, in which one pump is placed under the other in such a mauuer, that 

 the one below discharges itself into the suction-tank of the one above. The 

 vertical lift of each pump is between 4 and 7 feet, the piston-stroke about 3 

 feet, the quantity of water lifted per stroke about 5 sho. 



The "pumpers" are paid either in daily wages, or at the rate of the avai'age 

 number of strokes ; in the above mentioned Beishi copper-mine for instance, 

 where 130 pumps are kept going to lift the water 222"'-, a laborer was paid 4.9 

 sen for every 1000 strokes. 



We will now with the aid of these figures compare the cost of this method 

 with that of a good modern pumping-engine: 1 sho is about 65 cub." Jap.; 1 

 gallon about 163 cub." Jap. 1 pump-stroke = 5 sho = 325 cub." = about 2 gallons. 

 1,000 pump-strokes therefore deliver about 2,000 gallons. 1,000 strokes with 

 130 pumps, which lift the water 222 meters = about 732 English feet, cost 130 >C 



4.9 sen = 637 sen. To lift 1 gallon 1 foot costs consequently in wages , ' — — - 



6 -i j o 2,000 X/ 32 



= 0.000430 sen, or as 1 gallon water =10 lbs. Engl., 1 footpound costs 

 Q.0000436 sen. 



Now, a good Cornish pumping engine lifts, with 1 hundred weight of coals 

 burned under the boiler, about 100,000,000 footpounds, that is : it lifts a hun- 

 dred million pounds of water one foot high. Putting the price of a ton coals at 

 yen 6, 1 cwt. would cost 30 sen. To lift the above quantity of 100,000,000 lbs. 

 of water one foot costs then in coals 30 sen, and the cost per 1 footpound would 

 amount to 0.000,000,03 sen. 



