71 



• C2) 



On the Action of Chloride of Zinc on Codeia. 

 Moment, light load, 



f__ , 2w + w 110 wjx w n x 2 

 $ = * o _P* +m= _-EI + -^-^ 2 — + 



Moment, heavy load, j 



Central moment, light load, *^=|) = -j^I + ^^l 2 ; 



Central moment, heavy load, $ '(cc = = — jE I — W ° "j^^ 1 I 2 . 

 Central deflection, light load, 



y =T,-P 2+ * oB+ F( wi th,=g=f + ^.^ j 



Central deflection, heavy load, (14) 



(13) 



Communications received since the end of the Session. 



" Researches into the Chemical Constitution of the Opium Bases. 

 — Part IV. On the Action of Chloride of Zinc on Codeia." By 

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

 Bartholomew's Hospital, and W. Burnside, of Christ's Hos- 

 pital. Received June 23, 1870. 



On endeavouring to prepare apomorphia by a cheap method, Mr. Mayer 

 and one of us heated morphia with chloride of zinc, to see whether the 

 elements of water could not be abstracted by this reagent (the results of 

 this reaction have not yet been published). Apomorphia having been ob- 

 tained in this manner, it seemed possible that apocodeia, that is codeia minus 

 the elements of water, might be prepared by a similar reaction. On try- 

 ing the experiment a new base was obtained, which proved on analysis to 

 be apocodeia. 



When hydrochlorate of codeia is heated with an excess of a concentrated 

 solution of chloride of zinc, to a temperature varying between 170° and 

 180° C, for about 15 minutes, the decomposition takes place ; on cooling 

 a yellowish-brown tarry mass separates from the liquid, which on further 

 cooling may be drawn into thin threads, and thus obtained almost free 

 from the excess of the chloride of zinc. This amorphous silk-like mass is 

 almost pure hydrochlorate of apocodeia. To obtain the base in a pure 

 state from this substance, the following method was employed : — 



The hydrochlorate was dissolved in hot water and precipitated by hy- 



