VOL. LXXVIII.] PHILOSOPHICAL TRANSACTIONS. SGQ 



One more observation I have only to make, viz. that all original motions are 

 by their nature perfectly unintelligible as to their cause ; who can tell the cause 

 of gravity, chemical attraction, &c. ? and so undoubtedly the attraction of life, 

 in its cause, can never be investigated, being, like all other attraction, a power 

 which 2 or more particles of matter have of coming near each other. But 

 though the study of causes of original powers be totally absurd and futile, yet 

 the laws of their action are capable of investigation by experiment, and applica- 

 ble to the evolving much useful knowledge. Need I remind this Society, that 

 the investigation of the laws of gravitation, by Sir Isaac Newton, has rendered 

 it immortal ? The investigation of the laws of the attraction of life has also 

 been greatly forwarded by one of its present members ; but it is an investigation 

 which will probably require ages to render perfect. 



///. Of a Mass of Native Iron, found in South America. By Don Michael 

 Rubin de Celis. From the Spanish, p. 37. 

 About 30 years ago, the various barbarous nations who inhabited the pro- 

 vinces of the great Chaco Gualamba, expelled the Spaniards from thence ; and 

 since that time the countries on the southern part of the river Vermejo, and 

 western of the great river Parana, have been almost totally deserted. The only 

 employment of the few Indians who dwell within the jurisdiction of Santiago 

 del Estero is to gather the honey and wax with which the woods abound. These 

 Indians discovered, in the midst of a wide-extended plain, a large mass of metal, 

 which they called pure iron ; part of which projected above the ground about a 

 foot, and almost the whole of its upper surface was visible. Intelligence of this 

 discovery was immediately communicated to the Viceroys of Peru. That such a 

 mass of iron should be found in a country where there are no mountains, nor 

 even the smallest stone within a circumference of 100 leagues, could not fail to 

 appear extraordinary, though we know there are mines of pure iron in Europe. 

 Some private persons, at the great risk of their lives, both from the uncertainty 

 of procuring food or even water (of which none is to be found but what rain 

 happens to be preserved in some natural cavities of the earth,) from the danger 

 of meeting the roving Indians, from the various wild beasts found in those plains, 

 such as tygers, leopards, tapirs, from the swarms of poisonous reptiles, and 

 finally from the endless thickets, led on by hopes of enriching themselves, 

 boldly undertook the journey, to obtain some of the metal. They transmitted 

 a part of it to Lima and Madrid, by which no other advantage was gained than 

 to ascertain it to be very soft and very pure iron. As it is forbidden by law, for 

 political reasons, to manufacture iron in that country, though different parts of 

 it abound with iron mines ; and as it was asserted, that the vein of iron extended 

 many leagues, the visible part being only its crest projecting above the ground, 



VOL. XVI. 3 B 



