156 THE MODEKX THEORY OF CHEMICAL TYPES. 



Nitrate potassa KO, NO5 



Acetate potassa KO, (€4113)03 



Sulj)li.ito potassa KO, SO3 



Bisiilphate potassa KO.SOa + HO, SO3 



Sulphate potassa and zinc KO, SO3 4- ZuO, SO3 



Upon tliis principle, and notwithstanding tlie fact that for a long time the 

 organic nulicals were entirely hyi)0tli(.'tical, the development of organic radicals 

 went jmri passu with the study of organic compounds. The following illus- 

 tration shows how the organic acids were subjected to the radical theory. 



Acetic (0.211)03 with radical acetylc (0211) 



Propionic (O4H:0O3 " propyle . . . (04113) 



Butyric (08ll7)03 " butyle . - - . (CaH,) 



Valerianic (OioIIg)03 " valyle.... -. (O10II9.) ^^c. 



The theory is so simple, so well known, so satisfactory in the explanation 

 of the phenomena to which it is applicable, that the reluctance to abandon it, 

 especially by chemists educated under its influence, is natural. That it has 

 been attacked vigorously, and almost to its fall, is owing to the present great 

 wealth of chemical compounds, and the discovery of phenomena Avhich cannot 

 readily, if at all, be brought in subjection to it. 



Daily the realm of chemistry is extending, and the boundary line between 

 organic and inorganic compounds is becoming more and more indistinct. If to 

 the atoms of carbon, hydrogen, oxygen, and nitrogen has been assigned a 

 greater facility of mutual chemical attraction, the reason lies less, perhaps, in a 

 peculiarity of the nature of these atoms, than in the kind of experiments to 

 which they have been subjected. Continually, elements formerly called in- 

 organic are added to organic compounds, and it is not too much to expect that 

 the same chemical attractions exist between all of the elements as between 

 C, H, 0, and N inter illis. If the right of combining, in indefinite number of 

 atoms, the original organic elements, gives rise to so many " changes,'" i. e., com- 

 pounds, what would it be if each of the sixty-four elements could play an equal 

 part with these? 



The number of possible chemical compounds would approach infinity, and 

 could only be conceived by the aid of comparison. It would be no exaggeration 

 to compare their number Avith the distance from the earth of the fixed stars ex- 

 pressed in feet, or even with the diameter of that great orbit in which our solar 

 system is supposed to be moving. 



It is true that theories are not formed to xaQQt future y^^axit?,; but, nevertheless, 

 a general consid(;ration that the radical theory Avas becoming daily insufficient 

 for the rapid increase of chemical facts, urged thoughtful men to invent a theory 

 which should, at least, generalize chemical compounds, and bring them into the 

 proper order and connexion to render their more perfect study possible. A 

 satisfactory theory has not yet been invented, and chemists are loath to aban- 

 don totally the electro-radical theory for that of types pure and simple. 



While the radical theory was in a very flourishing condition, certain newly ob- 

 served phenomena demonstrated that avc could substitute electro-negative chlo- 

 rine for electro-positive hydrogen in a compound M'ithout changing the chemical 

 character of the body to a great extent. Thus, by the action of chlorine (01) 

 upon olefiant gas, (O4 H4,) four Dutch chemists had many years ago discovered a 

 peculiar compound, whicli has received the name of Dutch liquid, and which 

 has the comjtosition C4 H4 OI2. When \\\K)\\ this body the action of chlorine 

 was continued, supported by sun light, it was discovered that a series of liquids 

 could be obtained having the samt; character as Dulch liquid, but differing in 

 that the hydrogen was replaced atom by atom by chlorine, thus : 



