^S DR. Bosxack. 0J7 Goulard's cxlTRAcTi 



Grs. Gm 



L^sd - - 6.12 rru r *-4 ('Lead 8.4- 



AceiicAcid 3. The fame quantify l^^.^ 



Water 30.2S ^^"^^^ ^^ ^ " Lwiier 28.76 



40.00 40.00 



converting thefe proportions into quantities of 100 grains 

 cuch they will be as follows, 



Sol. acet. lead* Aq. lith. acet; 



, Lead - - - 15.3 21. 



Acetic acid - 7.5 5. 



Oxygene - 1.5 2.1 



Water - - 73.7 71.9 



100.0 100.0 



The cxperi- From this ftatement it appears^ that in the aq. lith. acet. the 



ments fhew that oxide of lead and the acid exift to each other in the propor- 



^eTatelrrdlffer- ^''^" ""^ "^^ ^^ ^> ^^ «^ ^^^ to 21.74, and we find that M. 

 entfalts. Thenard has defcribed the perfed acetate of lead, as a fait 



in which the oxide and the acid exift in the proportion of 100 

 to 21.79. So near a coincidence between thefe two propor- 

 tions can fcarcely be regarded as the nriCre efFe6t of accident ; 

 but maft rather be confidered as a proof that the fubftances 

 operated upon were nearly, if not altogether, identical. Ad- 

 The former rnitling this to be the cafe, we mufi conclude that the aqiia li' 

 being at fatura- tlmrgyri acetati is a faturated folutiori of the proper acetate of 

 *'°"* lead, that it is an efTentially different fait from the fuper-ace- 



— and the latter t ate of lead, and that it is not, as has been imagined, an acci- 

 afuper-acctate. j^^j^j compound, but an exaaiy neutralized fait, the confti- 



tuents of which exift in a conftant ratio to each other. 

 The neutral It happens in this, as in other infiances, that the ingredients 



connpound is compoiine the completely faturated compound, poflefs a weaker 

 compofed, affinity tor each other than when they exilt m a different pro- 



— and is there- portion. To this circuinftance muft be attributed the fuperior 

 fore a better teft jelicacy which Goulard poirefies, as a teft of animal and ve-' 

 getable mucus, over the fuper-acetate of lead, or the common 

 cerujju acetata. The aqua litharsyri acetati is fpcedily decom- 

 pofed by the adion of the atmofphere, in Confequence of the 

 oxide of lead which enters into its compofition having a 

 ftronger affinity for carbpnic than for acetic acid; this efFe6t 

 takes place in a lefs degree, in a faturated folution of fuper- 

 acetate of lead. 



V From 



i 



