\Chem"is*try\ (k[e^]m"[i^]s*tr[y^]; 277), n. [From
{Chemist}. See {Alchemy}.]
1. That branch of science which treats of the composition of
   substances, and of the changes which they undergo in
   consequence of alterations in the constitution of the
   molecules, which depend upon variations of the number,
   kind, or mode of arrangement, of the constituent atoms.
   These atoms are not assumed to be indivisible, but merely
   the finest grade of subdivision hitherto attained.
   Chemistry deals with the changes in the composition and
   constitution of molecules. See {Atom}, {Molecule}.
Note: Historically, chemistry is an outgrowth of alchemy (or
      alchemistry), with which it was anciently identified.
2. An application of chemical theory and method to the
   consideration of some particular subject; as, the
   chemistry of iron; the chemistry of indigo.
3. A treatise on chemistry.
Note: This word and its derivatives were formerly written
      with y, and sometimes with i, instead of e, in the
      first syllable, chymistry, chymist, chymical, etc., or
      chimistry, chimist, chimical, etc.; and the
      pronunciation was conformed to the orthography.
{Inorganic chemistry}, that which treats of inorganic or
   mineral substances.
{Organic chemistry}, that which treats of the substances
   which form the structure of organized beings and their
   products, whether animal or vegetable; -- called also
   {chemistry of the carbon compounds}. There is no
   fundamental difference between organic and inorganic
   chemistry.
{Physiological chemistry}, the chemistry of the organs and
   tissues of the body, and of the various physiological
   processes incident to life.
{Practical chemistry}, or {Applied chemistry}, that which
   treats of the modes of manufacturing the products of
   chemistry that are useful in the arts, of their
   applications to economical purposes, and of the conditions
   essential to their best use.
{Pure chemistry}, the consideration of the facts and theories
   of chemistry in their purely scientific relations, without
   necessary reference to their practical applications or
   mere utility.