Miscellanies. 357 
It was conceivable that in bodies differing as to their atomic con- 
_ stitution in this one point only, the elements might be more or less 
_ condensed, or otherwise so differently grouped as to give rise to the 
_ observed difference in their properties. But the progress of the sci- 
ence has removed this distinction also, and made us acquainted with 
instances in which like elements grouped together in like number and 
_ proportion, constitute unlike compounds having the same atomic 
weight. 
_ Dr. Dalton, in his reasonings on atomic arrangement, had early 
shown that the atoms of compound bodies might be supposed to 
_ group themselves in one of several different ways. Berzelius in 1814 
had proved, by his experiments on Tin, that there existed two chlo- 
rides and two oxides of that metal, having the same atomic consti- 
tution but possessing unlike properties ; and Dr. Thomson in his Furst 
Principles, in treating of the then supposed identical composition 
of the acetic and succinic acids, has made it exceedingly probable 
that there did actually exist very unlike chemical compounds in which 
the same elements in the same relative proportion were so grouped 
together as to produce the same atomic weight; but it was not tll 
the appearance ofan admirable paper by Berzelius, on the composition 
of the Tartaric and Paratartric (Racemic) Acids, that the doctrine 
was fully established. In this paper he showed that these two acids 
on the one hand, and the phosphoric and paraphosphoric on the other, 
are identical in composition, and for such bodies he proposed the 
term Isomeric (iog equil, wepoc part). ‘The able and interesting re- 
searches of MM. Wohler and Liebig on the acids of cyanogen, 
added to the list, by showing that the soluble and insoluble cyanuric 
acids 2 (Cy+20+H); the cyanic and fulminic acids were also 
isomeric. 
Many other examples have since been brought forward, and the 
investigation of organized compounds is daily adding to our knowledge 
on this important subject. ‘The doctrine itself has likewise met with 
general reception; and in adverting to the enlarged ideas it has al- 
ready given birth to, we cannot help regarding the establishment of 
it as a new bound the science has taken towards that vast extension 
it is destined to attain. 
4. Water, maximum density of. J. G.—The question as to the 
temperature at which the density of water is a maximum does not 
seem to be yet quite settled. Deluc first fixed it at 40° Fah.; 
