216 DESTRUCTIVE DISTILLATION OF ANIMAL SUBSTANCES. 



dipyridine in the same manner as ammonium is to ammonia. Should this 

 view be correct, it seems probable that, on the addition of hydrochloric acid, it 

 should, like a metal, evolve hydrogen. An experiment was made to ascertain 

 whether this occurred by introducing a quantity of the compound into ajar over 

 mercury, and bringing hydrochloric acid in contact with it ; but the anticipated 

 result was not obtained, — no hydrogen was evolved, but a brownish precipitate 

 appeared in the fluid, and the gray powder at once disappeared. I have been 

 unable to pursue this subject further, but propose to return to it on a future 

 occasion. 



Numerous experiments have been made, in the hope of throwing light on the 

 nature of the chemical changes occurring during the first process of preparing 

 dipyridine ; but it is obviously of a very complex kind, and some of the products 

 must be the result of secondary decompositions. IVfy impression is, that sodio- 

 dipyridine must be first formed, probably C 10 H 8 Na 2 N.,. In this case hydrogen 

 must be given off during the action, and this is actually the case, as was estab- 

 lished by direct experiment ; but the quantity evolved is trifling compared with 

 that of the sodium consumed, so that if the action takes place in this way, a 

 large part of the hydrogen must be converted into some other compounds within 

 the mixture itself. The light bases already mentioned might account for this, 

 if it were not that they are produced in very small quantity. Altogether I am 

 inclined to think that, in the first process, a number of secondary reactions take 

 place, which greatly complicate matters, and that it is through some modifica- 

 tion of the second by which an explanation will most probably be obtained. I 

 am still engaged with the subject, and have already nearly perfected a process 

 by which some of the products can be obtained with greater certainty and in 

 larger quantity than by either of those described in this paper, and which I hope 

 will enable me to subject the constitution and relations of these curious com- 

 pounds to a more minute examination. 



