186 



PROPORTIONS DETERMINATE. 



If an organic substance cannot be combined with an 

 oxide of composition, it Js impossible to find, with any 

 certainty, what number of molecules it contains ; be- 

 cause a very small difference in the numerical result of 

 the analysis, especially in the quantity of the hydro- 

 gen, may produce very great mistakes when the num- 

 ber of atoms contained by each element is attempted 

 to be calculated. To convince ourselves of this, we 

 have only to compare the numbers resulting from the 

 analysis of tartaric acid and of saccolactic acid, or the 

 analysis of starch with that of sugar. In analyzing in- 

 organic substances, two experiments on the same sub- 

 stance frequently differ more widely than the analyses 

 now mentioned. 



From his researches, M. Berzelius draws the follow- 

 ing conclusions. Inorganic nature differs from organic, 

 in the circumstance that the former is composed of bi- 

 nary combinations (combinations of two elements) ex- 

 isting alone, or combined among themselves. Every in- 

 organic substance, whatever be the number of its ele- 

 ments, is capable of being decomposed into binary com- 

 binations, and of being recomposed from them ; so that 

 in all inorganic substances, the compound bodies of the 

 Jtrst order, that is to say, bodies compounded imme- 

 diately of elements, contain but ttvo of those elements. 

 What still farther characterizes inorganic composition, 

 is, that on seeking the number of molecules contained 

 in each compound particle, whatever be the number of 

 elements, one of them is found to appear there only 

 by a single molecule ; except in some saline combina- 

 nations, where two molecules of one of the combustible 

 radicals are in a few cases combined with three of the 

 other. 



Inorganic nature, compound bodies of thejirsl order, 

 or bodies composed immediately of elements, contain al- 

 ways more than ttvo, and oxygen is constantly, without 

 exception, one of them. None of those elements is of 

 necessity single; and their combinations appear to be 

 capable of taking place, according to an almost infinite 

 number of proportions ; from which results a boundless 

 variety of organic substances composed of 3 and 4 ele- 

 ments. Upon this principle we can understand how 

 nature, without violating the laws of chemical propor- 

 tions, may produce several different species of sugars, 

 of gums, starch, resins, and so forth ; because the 

 particle of cane-sugar, for example, being composed of 

 10 O + 12 C a -f-21 H, by adding or subtracting a mo- 

 lecule of any one of its elements, there would result a 



different body, the elements and composition of which 

 are, however, too little altered to make it cease from 

 being sugar, though of another species. 



As to ammonia y the composition of which is not to 

 be found in any of the tables given above, Berzelius 

 considers it as a production of organic nature, formed 

 according to the same principle as other such produc- 

 tions ; that is to say, of oxygen combined with two 

 combustible radicals, hydrogen and the supposed radi- 

 cal of azote. The combination consists in the present 

 case of one molecule of oxygen, one of the radical of 

 azote, and six of hydrogen. Other chemists consider 

 it as compounded of three molecules of hydrogen, and 

 one of azote. 



Some time previous to the labours of Berzelius, 

 MM. Gay Lussac and Thenard had analyzed several 

 animal and vegetable substances by burning them 

 with superoxygenated muriate of potass. Many of 

 their results coincide pretty nearly with those of Ber- 

 zelius ; others differ from them. Determinate propor- 

 tions had not then become an object of attention to 

 chemists ; and consequently MM. Gay Lussac and 

 Thenard have but slightly considered them. They 

 regard vegetable substances as composed of water and 

 carbon, whenever hydrogen and oxygen appear in the 

 proportions forming water. They regard animal sub- 

 stances as composed of water, ammonia, and carbon, 

 having sometimes one element in excess, sometimes 

 another. This idea, however, in their use of it. 

 amounts to nothing more than a mode of exhibiting 

 those proportions which subsist among the elements. 

 After the work of Gay Lussac and Thenard, M. de 

 Saussure engaged in the analysis of alcohol and ether. 

 He performed his experiments with great care. Fol- 

 lowing the method of the chemists just mentioned, he 

 considers alcohol as compounded of two parts by 

 weight of olefiant gas, with one part of water, both re- 

 duced to their elements; and ether, as compounded of 

 four parts by weight of olefiant gas, and one of water. 

 Though it cannot be affirmed that M. de Saussure has 

 deceived himself in assigning these proportions, it is 

 nevertheless clear that his mode of considering organic 

 composition renders it absolutely analogous to that of 

 inorganic substances. Under this point of view, it is 

 impossible to understand those innumerable variations 

 which occur in bodies of a similar nature ; because it" 

 those combinations of carbon and olefiant gas with 

 water took place according to the laws of chemical 

 proportions, as they are obeyed by all binary combin- 

 ations, the actual multiplicity of organic combinations 

 could not possibly exist, and the whole would remain 

 confined within the narrow limits prescribed to inor- 

 ganic nature. 



After this historical exposition of the leading facts re- 

 lative to chemical proportions, with the various modes 

 employed to explain them, and elicit their general laws, 

 gome observations will be necessary with regard to the 

 speculative part of the subject. We shall conclude by 

 detailing the opinions entertained upon this subject 

 by the most illustrious chemists of our age. 



The state of philosophy, it is clear, produces a con- 

 siderable influence on the degree of interest excited by 

 each fresh step in the sciences ; and frequently the co- 

 lour assumed by a new discovery depends altogether 

 on (this circumstance. In former ages, the ideas enter- 



* By capacity of saturation is understood the quantity of oxygen found in that portion of a base, by which a hundred parts of the particu- 

 lar substance are neutralized. 



