218 ANNUAL OF SCIENTIFIC DISCOVERY. 



solution of bisulphite of soiliuin with zinc out of access of the air, 

 coolini:: tiu' mixture to avoid a rise of temporature, and d('cantin<j:; 

 the licpiid into three times its bulk of alcohol. This mixture is 

 hcrniclically scak'd in a llask, until there luis fallen a crystalline 

 deposit, consisting mainly of the double sulphite of zinc and sodi- 

 um. The clear alcoholic solution is then decanted into another 

 flask, which it should lill, and sealed up. There forms in the 

 flask a mass of colorh'ss, ucedle-like crystals, which, dried in a 

 vacuum, eflloresce to a white powder of tiie composition, 

 S2().iII,NaO. 



This sodium compound is more stable than the acid itself, 

 which may be oblaini'd in solution by adding dilute sulphuric or 

 oxalic aciil to the crystals. 



If a solution of bisulphite of sodium be placed in a porous 

 vessel, this vessel i)Ut into one containing water acidulated with 

 sulphuric acid, and the negative pole of a battery be inserted into 

 the bisulphite, while the positive pole is in the acidulated water, 

 oxygen is disengaged from the positive pole, while no gas es- 

 capes from the negative pole. At the same time the bisulphite 

 solution acquires the decolorizing property, owing to the forma- 

 tion of the hydrosulphite of sodium. — Comptes liendus, July I'J, 

 1809. 



RESEARCHES ON RESINS. 



M. Sace had published the results of his researches, which ex- 

 tend to copal, amber, dammar, colophony, lac (or shellac), 

 elemi, sandarac, mastic, and carnauba wax (a resin). The au- 

 thor has studied the greater or less degree of readiness wherewith 

 resins are reduced to powder, the action thereupon of boiling 

 water, of alcohol of 86 per cent, strength, of ether, of ordinary 

 acetic acid, of a hot solution of caustic soda of 1.074 sj)eciflc 

 giMvity, of sulphide of carljon, of oil of turpentine, of boiled 

 linsci'd oil, of benzine, of naphtha, of sulphuric acid of 1.8.'3 spe- 

 cilic gravity, of nitric acid of 1.329 sp(?cilic gravity, and of 

 caustic ammonia. All the resins were treated in powder; 

 and the solvents, three times as large a bulk as that of the resins, 

 have acted for at least 24 hours, at temperatures vary- 

 ing between 15° and 22°. The results arrived at are briefly as 

 follows: All resins sul>mitted to experiments fuse quietly when 

 heated, excepting amber, shellac, elemi, sandarac, and mastic, 

 which swell up, and increase in bulk. Only the carnauba wax 

 melts in boiling water; colophony becomes pasty therein, while 

 dannnar, shellac, elemi, and mastic agglutinate. Copal, ami)er, 

 and sandarac do not change. Alcohol does not dis.solve amber 

 nor dannnar ; it agglutinates copal, jiartly dissolves clcMui and car- 

 nauba wax, while colophony, shellac, sanilarac, and mastic are 

 readily soluble therein. Ether does not dissolve amber and 

 shellac, makes copals swell, and partly but slowly dissolves car- 

 nauba wax ; dammar, colophony, elemi, sandarac, and mastic 

 are readily (lissolved therein. Accitic acid does not dissolve; am- 

 ber and shellac; causes copal to swell ; acts somewhat upon car- 



