ANALYSIS OF LITIIOMARGE. 167 



paratcd from each other by a little warm water. 

 ]>ut as it was fcarcc pofliblc to prevent fomc of 

 the gypfum alfo from being taken up, another 

 evaporation and folution became nccettary to 

 get rid of" it entirely. In this experiment, the 

 iolution of vitriolatcd magnolia, when precipi- 

 tated by aerated fixed alkali, gave 3.1 ; and that 

 of vitriolatcd chalk, by the fame medium, 2.7 ; 

 the weight of the aerated chalk employed as a 

 precipitant being fubt rafted. Twice the amount 

 of thele fums indicates the quantity of each con- 

 tained in a hundred weight. J5ut it mull be ob- 

 fcrvcd, that the liquors remaining after the pre- 

 cipitations made by aerated alkali, hold a por- 

 tion of the fedimcnt in folution, by means of the 

 aerial acid; but this may be recovered from 

 them by boiling them during a quarter of an 

 hour *. It is ncceilary, however, to add this 

 L 4 to 



* Tli.it argillaceous earth may be diflolvcd by the acri.il a- 

 cid, ii affinal in the til vol. of thde Kfl'iys. BiU a certain 

 proportion of phlogifton mi^ht perhaps aflV.l the folution licre, 

 in the fann* manner it dots when the calces of fome metals arc 

 lo he difl'iilvcd. 'i'in ought LobcdephlogiAicatcd to a certain 

 point, l)ffore the aeid mcnflruacan aC\ uj)on it ; hut if it is too 

 much dcpritcd of its pldogirton, tlie acids lufe all their power, 

 i'hloginon therefore affilU tlte folation, but doej not direcAly. 

 creation it *, nnlcfs we chufe to a ffccl novelty of cxprcfTion. 

 Rut if any one thinks otherwjfe, let him defcrihc t!c method 

 hv which argillaceous earth c ui be difTolrcd in water with 



' O 



j)!ilo^il\on only. When argillaceous earth is roaflcd in the Tire, 

 in give* out a quantity of aerial acid. 



