284 SCIENCE IN SHORT CHAPTERS. 



all understood. It is very probable that the old alchemists 

 had a hand in this. 



In their search for the philosopher's stone, the elixir of 

 life, or drinkable gold, and for the universal solvent, they 

 mixed together everything that came to hand, they boiled 

 everything that was boilable, distilled everything that was 

 volatile, burnt everything that was combustible, and tor- 

 tured all their "simples" and their mixtures by every con- 

 ceivable device, thereby stumbling upon many curious, many 

 wonderful, and many useful results. Some of them were 

 not altogether visionary were, in fact, very practical, quite 

 capable of understanding the action of caustic lime on car- 

 bonate of soda, and of turning it to profitable account. 



It is not, however, absolutely necessary to use the lime, 

 as the soda plants when carefully burned in pits dug in the 

 sand f the sea-shore may contain but little carbonic acid if 

 the ash is fluxed into a hard cake like that now commonly 

 produced, and sold as "soda ash." This contains from 

 three to thirty per cent of carbonate, and thus some 

 samples are nearly caustic, without the aid of lime. 



As cleanliness is the^Pundamental basis of all true physi- 

 cal refinement, it has been proposed to estimate the pro- 

 gress of civilization by the consumption of soap, the relative 

 civilization of given communities being numerically meas- 

 ured by the following operation in simple arithmetic: Di- 

 vide the total quantity of soap consumed in a given time 

 by the total population consuming it, and the quotient ex- 

 presses the civilization of that community.* 



The allusion made by Lord Beaconsfield, at the Lord 

 Mayor's dinner in 1879, to the prosperity of our chemical 

 manufactures was a subject of merriment to some critics, 

 who are probably ignorant of the fact that soap-making is a 



* The scientific pedant of the Middle Ages displayed his profundity 

 by continually quoting Aristotle and other "ancients." His modern 

 successor does the like by decorating his pages with displays of alge- 

 braical formulae. In order to secure the proper respect of my readers 

 I here repeat the equation that I enunciated many years ago, "c= s " 



where e stands for civilization, s for the quantity of soap consumed 

 per annum, and p the population of a given community. 



