178 Miscellanies. 
3. On the Isomeric bodies of J. J. Berzetrus.—The number of 
known bodies, which show different properties, notwithstanding their 
equal qualitative and quantitative composition, has increased of late 
very considerably. By the name of isomeric bodies, we signify such 
substances as possess by equal quantitative (per cent.) composition, 
also equal atomical weight; but Berzelius has, quite recently made 
more distinctions on the same, and defines them by the name of 
asomeric, metameric and polymeric bodies :-— 
1. Isomerism ; bodies possessing equal procentic (quantitative) 
composition, and equal atomical weight, or bodies composed of equal 
absolute and relative number of atoms, as for instance the two oxides 
of tin, both the phosphoric acids, &c. 
2. Metamerism, (properly a modified isomerism,) where the same 
number of equal simple atoms are unequally distributed among com- 
pound atoms of the first order ; for instance, sulphate of tin (Sn S) 
and di-sulphate of tin (Sn S) possess an equal, absolute and relative 
number of the same elements, they are however to be considered 
(should the latter salt be really in existence, which is not hitherto 
known,) as different bodies, which may however unite by transposing 
their constituents. The cyanuric and hydrocyanic acids exhibit 
another instance of metamerism. 
3. Polymerism ; bodies having equal quantitative composition, but ~ 
unequal atomical weight, or where bodies have an equal relative but 
unequal absolute number of atoms; for instance, the relative atomi- 
cal number of carbon and hydrogen in the olefiant gas and ethereal 
oil is quite alike, for the number of atoms of hydrogen is in both 
twice as much as that of the atoms of carbon; but one atom of the 
gas contains but one atom of carbon and two atoms of hydrogen, 
(CH?) whereas one atom of the oil contains four atoms carbon and 
eight atoms hydrogen (C?H*). It is very desirable that a general 
term should be given for designating these three classes, and it is the 
more necessary on account of many substances not yet having a de- 
termined atomical weight, and we should be at a loss to classify many 
bodies, which show equal properties and equal composition.— Trans- 
lated by Dr. Lewis Feuchtwanger. 
4. Sparks in the freezing of water by ether.—Pontus, professor of 
chemistry at Cahors, has observed, that if the freezing of water is 
performed in a small glass bottle, terminating in a thin neck of 1—2 
cent. length, around which some cotton, moistened with ether is wrap- 
