^6i 'Decontpdjit'ion of the Acetiie of Lead, 



were Sufficient to fill each jar to the commencement of the 

 neck, the height of which was about three centimetres. I 

 then fixed to two pieces of cork defined to chife the mouths 

 of the jars a bit of zinc weighing 32'9456 gramme^; (fix gros) 

 by means of a piece of brafs wire exceedingly fine, but of 

 fuch a length as to allow the metal to be immerfed only fon-.e 

 millimetres in the foluiion. 



I then adjufted, and luted to the aperture of each vefiel, a 

 bent tube, which proceeded under the receiver of a pneu- 

 matic tub. Thefe two experiments, begun on the 29th of 

 Thermidor, year 9^ the centigrade thermometer being at 14'^ 

 above zero, exhibited the following phaenomena. 



Six ho'us after the apparatus was arranged, the jar No. I. 

 was {till fomewhat turbid, while that of No, II. was tranf- 

 parent, and the whole fui^erahundant (ait, after the faturation 

 of the liquor, was entirely precipitated. At this period the 

 zinc in the fecond jar was covered with fmall metallic fcalc«, 

 which could not be perceived in the firit. 



Next day both liquors were perfe6l!y tranfparent, and the 

 decompofilion feemed to have made equal progref? in both 

 veffcls. I only remarked, that the interior fides of the jar 

 No. I. were lined with a whilifli faline firalum, which ex- 

 tended from the middle of the vclfel to the bottom. 'J he 

 fmall fcales adhering to the fides and bottom of the piece of 

 zinc, by increafing in volume, had aflTumed the form of a 

 leaf of fern in the jar No. I., and was exceedingly delicate in 

 No. II. . 



I obferved alfo at the upper furface of the bit of zinc a kind 

 of metallic mofs'-, having that livid afpeft which charac- 

 terizes plates of lead expofed for fome lime to the contact of 

 the air. The faline Itraium oF No. T. daily decrcafcd to tlie 

 eighth, when it entirely difappeared. In the courle of thefe 

 two experiments there was difengaged a very fmall portion of 

 elaftic fluid, whicli when examined was found to be almo- 

 fpheric air. The quantity of this air appeared to lie more 

 confiderable in the apparatus marked No. I.; and this ap- 

 peared to me to arife from the cf)n)mon water employed, 

 which always contains more or Icfs of it. The remainder of 

 the operation exhibited nothing remarkable but an increafe 

 in the volume of the reduced "metal until the period of the 



* This metallic mofs in a tree of Saturn, prepared a yearVcfore, was 

 found to be covered by a very hue red powder, which occojiicd both the 

 Surface of the zinc and that of a portion of the undtcompoled acetite of 

 lead which covered the horizontal bottom of the glafs vtlicl. I confider 

 this red powder as produced by carburet of iron, from which zinc is ncvif 

 free, and which during the operation has been cdrricd to tlie flate of car- 

 bonate. 



dccompo- 



