THE CHEMIST AS A CONSTRUCTOR. 803 



peculiar structure and appearance frequently met with unsur- 

 passable difficulties. Even our most modern expedients do not 

 enable us to imitate more than a few well characterized and crys- 

 tallized minerals regarding shape, luster, and other physical prop- 

 erties. We can build up the carbonates of calcium, iron, and man- 

 ganese from their elements, but we lack the means to give them 

 the rhombohedral form in which they are naturally found. It 

 was only in the course of the last year that Krontschuff made 

 known the first method of crystallizing silica in the hexagonal 

 form of quartz ; and that Fremy and Meunier succeeded in gain- 

 ing real rubies and spinels by a melting process. It also required 

 long years of incessant experimenting to find out a way of manu- 

 facturing the splendid blue coloring matter, ultramarine, as an 

 approximative imitation of lapis lazuli. We should be at a loss, 

 if requested to prepare crystallized manganic binoxide, or cal- 

 cium triphosphate, or most other crystallized compounds spread 

 throughout the rocky schists of the earth. 



Asking for the reason of this insufficiency of our chemical fac- 

 ulties, we find it to be the impossibility of providing, through a 

 sufficient length of time, those conditions of heat, pressure, and 

 other circumstances which prevailed and were of influence when 

 such compounds were separating from molten masses of mineral 

 matter, or from saturated solutions, the composition of which will 

 always remain concealed from us. Organic substances, on the 

 contrary, of the most various kinds, are continually formed and 

 decomposed in the bodies of plants and animals, very readily com- 

 bining and separating under conditions which exist everywhere, 

 or which may easily be induced. The extraordinary mutability 

 of the compounds of carbon with hydrogen and oxygen is a feat- 

 ure particular to this element, not equaled by those of any other. 

 Their liability to chemical changes enables us voluntarily to build 

 up and to reconstruct carbon compounds occurring in organisms 

 as well as those derived from them. 



Alcohol, one of the best-known products of chemical industry, 

 may serve as evidence to what degree of perfection the composi- 

 tion and decomposition of chemical compounds has been brought. 

 As the chief constituent of intoxicating beverages, alcohol, to- 

 gether with carbonic acid, originates by fermentation from sugar ; 

 but this is not the only possible way to produce it. The bright- 

 ness of electric lights, by which public places, roads, stores, etc., of 

 our cities now are illuminated at night, is emitted by an electric 

 current passing between two carbon points. When such a passage 

 of electricity takes place in a glass balloon filled with hydrogen, 

 the electric current causes this gas to unite with carbon, forming 

 acetylene^ a gaseous compound, which in contact with more hydro- 

 gen readily takes it up, forming a second gaseous compound — 



