SALINE EFFLORESCENCE UPON WALLS, &C. 375 



muriatic acid were added ; no effervefcence was excited. By 

 the application of a gentle heat the vfhole was ditTolved, ex- 

 cept a few films that fwain in the fluid. A copious precipi- 

 tation was produced in this folution by pure ammonia, but 

 none by the carbonate of ammonia. A part of the muriatic 

 folution was evaporated; the refidue was not foluble in water, 

 but was fpeedily re-difloived by the muriatic acid. The mu- 

 riatic folution, faturaled with the carbonate of ammoniac, had 

 a precipitation produced by the oxalate of ammoniac. It ap- It wasphofphate 

 pears therefore that the concretion confifted of the phofphate °^ ""^^ '^^^^y* 

 of lime, mixed with a little animal matter, probably coagu- 

 lated albumen; it did not contain any carbonate of lime, and 

 its component parts appeared not to pofTefs any regularly or- 

 ganized ftru6lure. M. Fourcroy * and Dr. Thomfont have 

 examined fimilar bodies, and agree in confidering the earthy 

 matter to be the phofphate of lime ; we may therefore reafon- 

 ably conclude that this fubftance always compofes the earthy 

 part of the falivary concretions. I am difpofed, however, to 

 differ from ihefe diftinguiflied chemifts in my idea refpedling 

 the nature of the animal matter which enters into their com- 

 potition ; M. Fourcroy confiders it as confifting of a fpecies of 

 mucilage, while Dr. Thomlon defcribes it as " a membranous 

 fubftance, which retains the (liape of the concretion after the 

 folution of the phofphate." This was certainly not tiie cafe -—with co3g«- 

 wiilh tl}e one which I examined. I am difpofed to confider '^"^^^^ *'''"'^*'^'- 

 the animal matter as coagulated albumen, rather than mucus, 

 in confequence of its infoluble nature, and the greater facility 

 with which it would on this account be detained by the phof- 

 phate of lime. 



The power which the eleSric fluid poffeHet;, when generated Mercury has not 



by the galvanic apparatus, of burning metallic plate^;, afibrds l^eretofore been 

 r , n 1 T I . . deflagrated by 



one ot the moft beautiful expenmenls oi which the fcience of galvanUm. 

 cheraiftry can boaft. All the metals have "by this means been 

 fubjeded to combultion, except mercury, which, owing to 

 iis fluidity, is incapable of being formed into thin laminze, + 

 I have, however, been fortunate enough to accomplifti this 

 «bjeft, and that by the moft iimple method- 



«■ Syfteme, IX.3C8, f Chemiftry, TV. 658, 



J Thomfltrs Chemiflry, I, 125. 



5) d' 2 I was 



