obtained a volatile liquid (_methyldichloramine_, CH3.N.Cl2), boiling
at 58-60 deg. C., which explodes violently when heated with water,
yielding hydrocyanic acid (CH3NCl2 = HCN + 2HCl). Well-dried
hydroxylamine hydrochloride is dissolved in methyl alcohol and mixed
with sodium methylate; a solution of methyldichloramine in absolute
ether is then added and an ethereal solution of diazomethane distils
over. Diazomethane is a yellow inodorous gas, very poisonous and
corrosive. It may be condensed to a liquid, which boils at about 0
deg. C. It is a powerful methylating agent, reacting with water to
form methyl alcohol, and converting acetic acid into methylacetate,
hydrochloric acid into methyl chloride, hydrocyanic acid into
acetonitrile, and phenol into anisol, nitrogen being eliminated in
each case. It is reduced by sodium amalgam (in alcoholic solution) to
_methylhydrazine_, CH3.NH.NH2. It unites directly with acetylene to
form pyrazole (H. v. Pechmann, _Ber._, 1898, 31, p. 2950) and with
fumaric methyl ester it forms pyrazolin dicarboxylic ester.
(F. G. P.*)

See G. T. Morgan, _B.A. Rep._, 1902; J. Cain, _Diazo Compounds_,
1908.

DIAZOMATA (Gr. [Greek: diazoma], a girdle), in architecture, the landing
places and passages which were carried round the semicircle and
separated the upper and lower tiers in a Greek theatre.

DIBDIN, CHARLES (1745-1814), British musician, dramatist, novelist,
actor and song-writer, the son of a parish clerk, was born at
Southampton on or before the 4th of March 1745, and was the youngest of
a family of eighteen. His parents designing him for the church, he was
sent to Winchester; but his love of music early diverted his thoughts
from the clerical profession. After receiving some instruction from the
organist of Winchester cathedral, where he was a chorister from 1756 to
1759, he went to London at the age of fifteen. Here he was placed in a
music warehouse in Cheapside, but he soon abandoned this employment to
become a singing actor at Covent Garden. On the 21st of May 1762 his
first work, an operetta entitled _The Shepherd's Artifice_, with words
and music by himself, was produced at this theatre. Other works
followed, his reputation being firmly established by the music to the
play of _The Padlock_, produced at Drury Lane under Garrick's management
in 1768, the composer himself taking the part of Mungo with conspicuous
success. He