96 UNEXPECTED DISCOVERIES. 



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 serviceable 

 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 

 burned from the state of two separate airs to the 

 state of liquid water, produce about the most in- 

 tense heat that could be produced, the statement 

 would have been treated as the dream of a distem- 

 pered imagination. There are innumerable cases, 

 too, in which that which has for centuries been 

 thrown away as the refuse, has, upon further dis- 

 covery, been found to be the most valuable part of 

 the whole composition. The ore of zinc, which, 

 united with copper, forms brass, used to be consi- 

 dered as an useless incumbrance by the miners in 

 several parts of the country. The bones of meat, 

 which were once scattered both unsightly and un- 

 profitably over the waste places, are now, in con- 

 sequence of a few very simple discoveries, made 

 probably more valuable, 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 



