4f6 7}3e Chr^foUte Jhnm io he ThJ^lait of Lwi/, 



was filtered j and the folid matter being collefted, waflied, and ignited in i filver crucible, 

 weighed ii6 parts. This matter, fubjeded to various proofs, exhibited all the charadlers of 

 ftilphate of lime. 



The filtered liquor was evaporated to drynefs in order to expel the fulphuric acid. The 

 rfefidue was du£lile, and might be drawn out into threads as long as it preferved its heat ; 

 but it hardened by cooling like a kind of glafs flightly opaque ; it weighed 46 parts. Thefe 

 forty- fix parts, dilTolved in water and mixed with carbonate of ammoniac, formed an 

 abundant precipitate which became ftill more abundant by heat. This precipitate feparaC- 

 ed by the filter, wafhed, and ignited in a filver crucible, weighed 11 parts. It was phof- 

 phate of lime not decompofed. 



The fluid thus cleared of the phofphate of lime was evaporated to the confidence of 3 

 fyrup. At the expiration of feveral days it afforded cryftals in the form of a four-fided 

 prifm terminating in quadrangular pyramids, whofe fides correfponded with thofe of the 

 prifm, and of a penetrating urinous tafte. Heat decompofed this fait, ammoniac was 

 driven oiF, and the acid remained in the fi;ate of a perfe£tly tranfparent glafs. The glafs> 

 mixed with the powder of charcoal and ftrongly heated in a retort, very fpeedily afforded 

 phofphorus. 



It cannot be doubted, therefore, but that this pretended ftone is a combination of time 

 and phofphoric acid; a true native phofphate of lime in crydals. Ncverthelefs, though I 

 am convinced by experience of the accuracy of the refult I have announced, I was defirou^ 

 of making fome other experiments in order that there might not be the flighteft doubt 

 upon the fubje£l. 



Experiment 3. One hundred parts of the fame fubftance in powder were digefted in 

 muriatic acid diluted with two or three parts of water. The folution took place fpeedily 

 *rithout the lead eifervefcence ; it was clear and colourlefs. 



This foluiion, evaporated nearly to drynefs in order to difpel the excefs of muriatic acid> 

 was again diluted with water, and mixed with a folution of oxalic acid, till the precipitate 

 which immediately followed was no longer produced. The filtered liquor left upon the- 

 paper a precipitate, which after walhing and drying weighed 118 parts. Thefe 1 18 parts of 

 precipitate, ftrongly calcined in a crucible, aflumed at firft a black colour arifing from the 

 coal of the oxalic acid decompofed by the fire. This coal being burned off, there remained 

 54,2s parts of a white puiverulent fubftance, which was acrid, foluble in water, turned 

 vegetable blue colours to a green, and, in a word, prefented all the charadcrs of pure lime. 

 The fluid from which the oxalate of lime had been feparated was evaporated to drynefs, 

 and alTumed a black colour on account of an excefs of oxalic acid which the heat had. 

 decompofed. 



When the whole of this laft acid appeared to have been entirely converted into carbonj^ 

 the refidue was difTolved in water, and the folution filtered in order to feparate the carbon. 

 The fluid part, faturated with carbonate of ammoniac, let fall a few light flocks of phofphate 

 of lime which weighed one part. This fluid, fubjeded to evaporation, afforded a fait 

 perfedly refembling that of the former experiment. It was decompofed by lime water, 

 and was fufed with the blow-pipe, with inflation, and emitted a fmell of ammoniac and' 

 a yellow greenifli light. The refi^ue was a tranfparent glafs. 



Since, therefore, this experiment perfedly agrees with the former, not only with regard 

 to the nature of the principles^of the chryfolite, but alfo the proportions, as will imme- 

 diately 



