18G9.] On the Action of Hydrochloric Acid on Codeia, 83 



identical with those of the above-mentioned previous researches ; and he 

 claims the following results as new : — The conditions as to transfer and 

 transformation of heat which must be fulfilled in order that permanence of 

 type may be realized, exactly or approximately, in a wave of finite lon- 

 gitudinal disturbance in any elastic medium ; the types of wave which 

 enable such conditions to be fulfilled with a given law of the conduction of 

 heat ; the velocity of advance of such waves ; and some special results as 

 to the rate of change of type in adiabatic waves. He also claims as new 

 the method of investigation by the aid of mass-velocity and mass- coordinates, 

 which he alleges to possess great advantages in point of simplicity. 



IV. "Researches into the Constitution of the Opium Bases. — 

 Part III. On the Action of Hydrochloric Acid on Codeia." By 

 Augustus Matthiessen, F.R.S,, Lecturer on Chemistry in St. 

 Bartholomew's Hospital, and C. R. A. Wright, B.Sc. Received 

 July 23, 1869. 



§ 1. On the Action of Hydrochloric Acid on Codeia. 



In Part II. (Proc. Roy. Soc. vol. xvii. p. 460) it was shown that when 

 codeia is heated with excess of hydrochloric acid under pressure that it 

 splits up into chloride of methyl, water, and apomorphia, thus — 



C 18 H 21 N0 3 + HC1= CH 3 CI + H 2 O + C 17 H 17 N0 2 . 



At the time it appeared probable that one of the two following reactions 

 would first take place, forming an intermediate product : — 



I. C w H 21 N0 3 + HC1=CH 3 C1+ C 17 H 19 N0 3 . 

 II. C 18 H 21 N0 3 = H 2 0 +C u H 19 NO a . 



On investigation, however, it has been found that neither the one nor the 

 other takes place, at least as the chief reaction ; for by heating codeia with 

 excess of hydrochloric acid on the water-bath, a body is obtained by the 

 following reaction — 



C M H 21 N0 3 + HC1= H a O + C H M CI N0 2 ; 

 and this base, when heated under pressure with hydrochloric acid, splits up 

 into chloride of methyl and apomorphia, 



C 18 H 20 CI N0 2 = CH 3 C1+ C„ H I7 N0 2 . 

 The new base may be obtained in a state of purity thus: — codeia is 

 heated under paraffin on the water-bath with ten to fifteen times its weight 

 of strong hydrochloric acid for twelve to fifteen hours, and the resulting 

 brownish liquid evaporated to dryness on the water-bath ; the residue is 

 dissolved in water, and excess of bicarbonate of sodium added, whereby a 

 voluminous white precipitate is formed, consisting chiefly of the new base 

 mixed with a trace of apomorphia. The filtrate contains the unaltered 



g 2 



