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after every foft animal organ has undergonethe utmoft effeft of fire ; and it may be de-tected in foludon in a great variety of animalfluids.

There are at leaft two ftates of phofphat oflime which fhould be well dillinguilhed. Oneis that in which the conftituent parts are fullyneutralized fo as to fliew no marks of excefseither in acid or bafe, and in this ftate it isa white powder, perfectly infoluble in water,nearly infufible, and in appearance refemblinga Ample earth. This is the ftate in which itexifts in bone-afh, of which indeed it forms byfar the greateft part, and was formerly calledthe earth of bones.

The other ftate which has been known muchlater, and which has never been found native,but is only known in the laboratory, is thatin which the acid is greatly in excefs, and maybe here termed fuper-phofphat of lime. It wasfirft detected in the acid liquor that is producedby decompofing bone-alh by fulphuric acid, isacid to the tafte, and in a red heat readily meltsinto a porous glafs. It was at firft miftakenfor pure phofphoric acid. It is not certainhowever whether the proportion of phofphoricacid in this fpecies is conftant, or whether itdoes not admit of an indefinite variety.

We fhall firft defcribe the common or neu-tral phofphat.

Phqsphat of Lime may be obtained quitepure either by faturating the pure acid with mar-ble and then evaporating; or by wafhing bone-afh with hot water to diflolve out any folublefait which it may contain; then adding a littleacetous or dilute muriatic acid till the effer-vefcence ceafes to engage the carbonat oflime which it contains, and again thoroughlyedulcorating.

This phofphat of lime is infufible per fe inthe molt intenfe heat, the utmoft effebt of firebeing only to reduce it to a porcellanous frit.With vitrefcent mixtures it makes glafles ofdifficult fufibility, and more or lefs opake, asdefcribed in the article Glafs.

It is entirely infoluble in water hot or cold.

All the acids, even the carbonic, aft upon itwithout difficulty; but probably in a differentmanner. If fulphuric acid is digefted with a^Y e ry fmall quantity of phofphat of lime a clearp ution is eftefted, which contains fuiphat of

a' t ^ !e ac idulous or fuper-phofphat of lime,and naked phofphoric a; d fulphuric acid. Thea . ^. r . aci therefore partiallv decompofes thep to p tat, and the fuper-phofphat, together with

1 Fourcroy Syfieme. k

the fuiphat of lime thereby produced, diffolvesin the excefs of acid.

When the proportion of phofphat of lime isgreater, the fame decompofition takes place,only the greater part of the refulting fuiphatof lime remains updiffolved, as is the cafe inthe common treatment of bone-alh with ful-phuric acid.

It is afferted by Vauquelin* that the nitricand muriatic, and fome other acids, act inthe fame manner on the phofphat of lime, andpartially decompofc it. It is not eafy however todemonftrate this, for when phofphat of lime, isdigefted with thefe acids, the nitric for example,a clear folution is made," (every product being,foluble whatever be the mutual adlion of thelefubftances) fo that the folution may eithercontain phofphat of lime limply diffolved un-decompoled by thefe acids, or it may confiftof fuper-phofphat of lime, nitrat of lime, andnitric acid in excefs.' On adding an alkali, pureor carbonated, to the folution, a white pre-cipitate falls down, which is phofphat of limeas before, but it is obvious that the adtion ofthe alkali may be either {imply to precipitatethe phofphat of lime by fuperior affinity withthe nitric acid; or, firft to faturate the excefsof phofphoric acid in the fuper-phofphat, andthus to bring it to the ftate of neutral phofphat,and then to precipitate it by engaging the acidwhich held it in folution. If a pure alkali isufed in this cafe the whole of the phofphat fallsdown; if a carbonated alkali, a part of thephofphat remains in folution by the help ofthe carbonic acid. Hence it may be inferred,.(which is the fadt) that even carbonated waterwill diflolve phofphat of lime.

Phofphat of lime is produced alfo by doubledecompofition, on dropping a folution of anyphofphated alkali into any foluble calcareousfolution that has not any great excefs of acid.Vauquelin alfo found k that on boiling phofphatof foda with wet and newly precipitated carbonatof lime, the fame refillt took pl ace, and carbonatof foda with phofphat of lime were produced.

The oxalic acid added to phofphat of limediffolved in any weak acid feparates almoft thewhole of the lime in the form of oxalat of lime,and oxalat of ammonia appears to feparateHie whole. From analogy it is probable thatfuiphat of ammonia would have the fame effedt.

The proportion of ingredients in this phof-phat as forming bone-afh, are ftated byVauquelin to be 41 per cent, of phofphoricacid and 59 of lime. But the phofphat formed