CHEMICAL SCIENCE. 197 



former. The following are the conclusions in his memoir, which will soon 

 be published. 



1. The compounds which the three kingdoms offer for our study, are re- 

 duced by analysis to a certain number of radicals which may be grouped in 

 natural families. 2. The characters of these families show incontestable anal- 

 ogies. 3. But the radicals of mineral chemistry differ from the others in this, 

 that if they are compound, they have a degree of stability so great that no 

 known forces are capable of producing decomposition. 4. The analogy 

 authorizes the inquiry whether the former may not be compound as well as 

 the latter. 5. It is necessary to add that the analogy gives us no light as to 

 the means of causing this decomposition, and if ever to be realized, it will 

 be by methods or forces yet unsuspected. 



To these remarks of Dumas, Despretz subsequently replied in his turn, 

 criticizing the ideas of Dumas on the unity of matter. According to him, 

 there is not a sufficient analogy between the radicals of organic chemistry 

 and the simple bodies of mineral chemistry. The first are decomposed by 

 heat, and converted by oxygen into water and carbonic acid. These organic 

 compounds thus disunited can never be again recomposed. It is well under- 

 stood to be quite otherwise in respect to the elements of mineral chemistry. 

 From this M. Despretz concluded that there is not only no analogy, but 

 that there is a complete contrariety, between the elements of organic and 

 inorganic chemistry; in a word, as far as he can discern, science furnishes 

 no indication favoring a belief in the decomposition of the bodies considered 

 simple, even by the aid of new forces. On the contrary, he thinks he has 

 demonstrated that the metals and metalloids are simple bodies. We have 

 already seen by what processes he thinks he has arrived at this conclusion; 

 lie returns to the subject now to show in what respects his experiments are 

 new, and says: "All chemists have ignited iron and platinum to a white 

 heat, but no chemist, to our knowledge, has ignited these metals in a bar- 

 ometric vacuum for the purpose of ascertaining whether any gas was 

 disengaged; and this is my experiment." 



" Nothing is disengaged under the action of heat, or of a spark from a 

 powerful induction apparatus. This negative result is of a nature to astonish 

 the partisans of the theory of Dr. Prout, if any exist. According to this 

 hypothesis, iron should retain about 80,000 and platinum 200,000 volumes of 

 hydrogen gas condensed into only one volume. How can we suppose that 

 a condensed gas could resist the test to which iron and platinum are sub- 

 jected in my experiment? Is there a single fact in physics and in chemistry 

 which authorizes such a supposition? In my process, the disengagement of 

 one-twentieth of a cubic centimetre of gas would have been readily appre- 

 ciable. To this slight weight the most delicate chemical balances would 

 have been insensible." 



The reply of Dumas is briefly as follows: "I demand of M. Despretz 

 why he expects the metals to resolve themselves into gas? why is it neces- 

 sary that the primary elements of bodies should be gaseous? As regards 

 the analogies between organic and inorganic chemistry, which are denied 

 by M. Despretz, I ask where is the chemist who would not unite in one 

 group cyanogen and chlorine, bromine and iodine? Where r,n> tl>^ differ- 

 ences between these two sets of substances? Do they IK/, biend in all their 

 chemical affinities? Does not the analogy between them extend even to a 

 similarity of atomic, volumes? It is true, cyanogen has been decomposed, 

 while the others have resisted decomposition; but he is greatly mistaken 



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