318 Mineral Riches of the Philippines. [July, 



spends itself then in augmenting the velocity of the moving 

 parts of the machine. 



On the other hand, if the machine is kept at a certain 

 speed of revolution whilst the outer circuit is broken, and 

 the circuit is then suddenly closed, the speed instantly 

 diminishes, showing that a portion of the force turning the 

 machine changes into electricity. 



These experiments show that, whether the machine be 

 active or passive, there exists always a state of equilibrium 

 between the expenditure of mechanical force and the 

 production of electricity. 



IV. THE MINERAL RICHES OF THE 



PHILIPPINES. 



By W. W. Wood, Hong Kong. 



PAIN has always prided herself on being a " nation 

 minera " — a mining nation — and there are few coun- 

 tries in which so great a variety and abundance of 

 mineral wealth is found as in the Peninsula, where many of 

 the mines have been worked from very remote times. Not- 

 withstanding the mining colleges and administrations, and 

 in spite of many modern inventions for saving time and 

 abridging labour, much of the gear used in the Spanish 

 mines is to this day of a very primitive description, and the 

 produce of the ores less than that obtained by the adoption 

 of modern machinery and improvements in smelting. This 

 being the case in the mother country, it is not difficult to 

 imagine that in a remote colony like the Philippines, and 

 one in which as yet little has been done towards exploring 

 the country from a mining point of view, the devices for the 

 extraction, &c, of ores are of a still more simple and in- 

 effective kind. In addition to this, a very misplaced eco- 

 nomy, or perhaps want of means, has prevented several 

 mining adventures, undertaken in various parts of the 

 Archipelago, from resulting favourably for the projectors. 



The interior of the great islands of Mindoro and Mindanao 

 are but little known, but from their extent and variety of 

 surface are probably rich in minerals ; but geological sur- 

 veys are extremely difficult, owing to the extent and im- 

 penetrable nature of the forests which cover the greater 



