290 THE POPULAR SCIENCE MONTHLY. 



make the famous Portland cement ; and the ruthless hand of Utilitarian- 

 ism has not even respected the brickbat, that had served from time 

 immemorial only to crack the heads of opposing factions, but grinds 

 it up to make cement with lime. The finest glue size is made from 

 the waste of parchment skins. The waste gases of the blast-furnace 

 are now utilized to heat the blast, to generate the steam that drives the 

 engine that makes the blast, to hoist ores, drive machinery, etc. ; and 

 even the slag, that has served for years only to decorate the hillsides, 

 is now cast into paving and building blocks, or granulated to make 

 building sand, or ground for cement, or mixed with suitable chemicals 

 and turned into the commoner grades of glass, or blown by a jet of 

 steam into the finest filaments to form the curious substance called 

 mineral wool, now largely used as a non-conductor of heat upon steam- 

 pipes, boilers, roofs, etc., etc. 



So, too, the enormous hills of anthracite-coal dirt, that in the coai 

 regions of our State have for years borne silent but eloquent testi- 

 mony to the crudity and wastefulness of our methods of mining coal, 

 now bid fair soon to disappear beneath boilers supplied with ingenious 

 dust-burning devices, or in the form of lumps of artificial fuel. Even 

 the anthracite-coal dej)osits, now so enormously valuable, were a few 

 years ago but so many layers of black stone, unappreciated and value- 

 less. The waste heat of the lime-kiln is made to generate steam, and 

 warm immense public buildings in England and on the Continent ; and 

 the " exhaust " of the steam-engine is made to do service in heating 

 the water fed into the boiler. 



I might multiply examples like the above almost indefinitely, to 

 show how, with the most beneficent results, the genius of invention 

 has enabled us to reap advantages where none were supposed to exist, 

 or where, if they were suspected, they were undervalued or simply 

 neglected. 



And now, having briefly shown, by a few typical examples, what 

 modern invention has done and is doing to utilize the waste products 

 of nature and of the arts, I shall invite you to consider with me whether 

 there are not waste forces in nature that can and should be turned to 

 useful account, or to vastly better account than we are now putting 

 them ; and whether we must not plead guilty to the crime of neglect- 

 ing to avail ourselves of exhaustless and incalculable stores of power 

 that simply wait to do our bidding. 



Before I pass to the consideration of what I have called the 

 " Waste Forces of Nature " by which I mean to designate such of 

 the natural powers as the world of industry has thus far passed over 

 altogether it will be instructive for us to consider whether we are 

 doing what we ought to do with those that are used, and whether, with 

 all the inventions of our skilled mechanics and engineers, the actual 

 practical results that we obtain from the various sources of power 

 used in the industries do not fall far below what theory declares it to 



