KNO®,, however, to a warm conce 
t 
pears to be the Faas as that which 
200 S. P. Sadiler on Fischer's Salt. 
gives us a very strong argument in favor of the exact analogy 
of the 8-atom soda salt and with it of Fischer's salt, to the 
cobalticyanid of potassium, from which the salts of Gibbs and 
Genth were formed. With this view of these salts, we are able 
to discern yet other analogies. Iridium forms a number of ses- 
quioxyd salts very similar to those of cobalt. We have, indeed, 
two double chlorids of iridium, exactly analogous to the 2-atom 
and 3-atom soda or ammonia salts. i 
Ir, Cl,+-4KCl and Ir,Cl,4-6KCl 
in which we should expect monatomic Cl to be exactly replace- 
able by monatomic N®, and so we find that it is. Dr. Gibbs 
has discovered an iridium salt, having the formula 
Ir,6NO,+6(KNO,)-+2H,9, 
an exact analogue of Fischer's salt. Lang* also has discovered, 
a rhodium salt, whose formula Rh,6N0,+6(KN®,) is precisely 
analogous. If we = together for a moment the three salts 
in question, their identity of constitution becomes apparent. 
Ir,0,, 3N,0,+3(K,0, N,@,) or Ir,6NO6,+6(KNO,)—Gibbs. 
Rh, O,,3N,6,+3(K,0, N,©,) or Rh,6N6, +6(KNO,)—Lang. 
©0283, 3N:0;+3(K,0, N @;) or €o0.6N0,+6(KNO2)—Sadtler. 
Tf, therefore, we are to place any dependence at all upon analogy; 
the universal occurrence of the hexatomic €o, atom in all our 
compounds, is what we should expect, a priori. The analyses 
of the series of salts I think fully confirms this expectation. 
I have now to discuss some related compounds—those formed 
in neutral solutions. Erdmann first pointed out the distinction 
tween these and the normal Fischer’s salt. He obtained and 
: z ntra: : 
nothing is formed but a flocculent yellow precipitate, which ap- 
I formed over mereury in the 
The formulas of these salts appear to be as 
_* Royal Swedish Acad. Trans., 1864. 
