UNEXPECTED DISCOVERIES. 107 



never can arrive, it is tantamount to saying, that we 

 should never despise, or cease further to examine, 

 any natural object whatsoever; because, even in. 

 the most common and neglected one there may be 

 properties more really useful than those of that 

 upon which we, with our present knowledge, what- 

 ever the extent of that knowledge may be, set the 

 highest value, There was a time when people 

 little dreamed that common coal might be made to 

 circulate in pipes like water, .and light up streets, 

 roads, and dwellings, and yet be nearly as service- 

 able as ever for common fires, and more ser/iceable 

 in all cases where smoke is objectionable ; and there 

 was also a time when, if any one had said that the 

 elements of water, mixed in the same proportion in 

 which they form that liquid, could, by being burnt 

 from the state of two separate airs to the state of 

 liquid water, produce about the most intense heat 

 that could be produced, the statement would have 

 been treated as the dream of a distempered imagina- 

 tion. There are innumerable cases, too, in which 

 that which has for centuries been thrown away as 

 the refuse has, upon further discovery, been found 

 to be the most valuable part of the whole composi- 

 tion. The ore of zinc, which united with copper 

 forms brass, used to be considered as a useless en- 

 cumbrance by the miners in several parts of the 

 country. The bones of meat, which were once 

 scattered both unsightly and unprofitably over the 

 waste places, are now, in consequence of a few 

 very simple discoveries, made probably more valu- 

 able, weight for weight, than the meat itself; and 

 the very dust and rubbish of the houses, which in 

 the places where it collects is absolute filth, is found 

 very serviceable in many of the arts, so that large 

 fortunes are made by people who collect it at their 

 own expense. It is scarcely possible to turn one's 

 attention to any one branch of industry in which 

 there shall not be found some substance of the 



