C H £ M I 
of foda in animal fubftancfis; they even appear to form 
together a triple fait, according to the proportions of 
each, which proves that they exercil'e a reciprocal attrac¬ 
tion, which occafions them to unite. Expofed to heat, 
the ammoniac is difengaged, and the phol'phoric acid re¬ 
mains in the vitrified Hate. It undergoes no change by 
expofure to the air. It is foluble in four parts of water, 
at the mean temperature of the atmofphere, and cryftal¬ 
lizes eafily into regular four-fided prilins, crowned with 
pyramids of the fame (hape. 
Charcoal decompofes this fait. For this purpofe, put 
into a retort a mixture of phofphat of ammoniac and 
of charcoal in powder; lute the retort with earth : place 
r balloon to receive the phofphorus, and a jar to coi¬ 
led! the ammoniacal gas which is difengaged ; a bent 
tube of fafety mull pal's from the balloon, to be plunged 
underneath the jar in the pneumatic mercurial apparatus. 
The pholjffioric acid is attacked by the charcoal, which 
feizes on the oxygen, and lets the phofphorus free; the ac¬ 
tion of the charcoal upon the pholphoric acid is affifted by 
lieat. To this operation mull the definitive operation be 
reduced, when the refidue, evaporated to the confiltence 
of honey, is decompofed, to fabricate the ■phofphorus of 
Kunkel-, for the pholphats of foda and lime, contained in 
the refidue, are not decompofed by the charcoal; it is 
only the phofphat of ammoniac, which being deprived 
of its ammoniac by the adtion of the heat which volati¬ 
lizes it, leaves the phofphoric acid at liberty; and then, 
the charcoal, ailing upon the oxygen, makes it eafy to 
diftil the phofphorus. This is the reafon why the pro- 
cefles with urine yield fo little phofphorus; and certainly 
it was long unknown that all the pholphorus of the acid 
conftituting the pholphats of lime and foda was negleiled 
and loft, becaufe they could not be decompofed without 
the agency of an acid, itronger in affinity for lime and 
foda than the phofphoric acid, and fuch are the nitric 
*nd fulphuric acids. 
The ftronger acids decompofe this phofphat; as do 
barytes, ftrontian, lime, potaffi, and foda: magnefia de¬ 
compofes it with heat, for in the cold a little magnefia 
will always remain. By mixing concentrated folutions 
of the phofphats of ammoniac and of foda, a triple com¬ 
bination is produced, called phofphat of foda and am¬ 
moniac. This fait cryftallizes and efflorefces in the air. 
Its prefence may be known as follows: If the mixture 
cf the triple fait is not well made, that Which is properly 
formed is evident by the efflorefcence, while the un¬ 
combined portion of phofphat of foda cryftallizes apart 
in a tranfparent rhomboid form. If, on the other hand, 
the ammoniacal phofphat is in excefs in this triple com¬ 
bination, it is eafily perceived alfo, becaufe the ammo¬ 
niac may be dilengaged by cauftic lime. 
This fait is one of the bell folvents that can be ufed 
in experiments with the blow-pipe: ithaftens thefulion 
of Hones, and the metallic earths and oxyds, the Ipecies 
of which is often known by the colour they communi¬ 
cate to it. 
Phosphat of Magnesia.— This fait is but little 
foluble in water yet fufficiently fo to furnilh long cry- 
ftals like flattened needles, very thin, and cut obliquely 
at the ends. We owe to Vauquelin the method of ob¬ 
taining it quickly, in folid cryftals of two or three in¬ 
ches long and one line thick. This method confifts in 
mixing equal parts of fulphat of magnefia and phofphat 
of foda, both diflolved in water. At firlt there appears 
to be no adtion between thefe fubftances ; but at the end 
of twenty-four hours, there will be found in the liquor 
prifmatic cryftals, perfedtly tranfparent, varying in fize 
according to the quantity of the falts employed. This 
iubftance, expofed to the air, lofes its water of cryftalli- 
zation, becomes opaque, and is even reduced to powder 
in a ftiort time; this proves that it has no great attrac¬ 
tion for water. It has no fenfible odour. It melts un¬ 
der the blow-pipe into a globule, which preferves its 
tranfparency after cooling. 
VOL, iv. No. J 5 *. 
S T R Y. 253 
The fulphuric, nitric, and muriatic, acids, feparate 
the elements of the phofphat of magnefia, by uniting 
with its bafe, and fetting; the phofphoric acid free. It is 
decompofed alfo by barytes, ftrontian, and lime : it is 
eafy to prove this, by pouring a folution of thefe earths 
into a folution of the fait, which immediately becomes 
turbid, becaufe thefe phofphats are much lels foluble 
than the magnefian. It is decompofed by the fixed cauftic 
alkalis, but not by ammoniac ; on the contrary, magnefia 
completely decompoles phofphat of ammoniac, efpeci- 
ally in a gentle heat. Phofphat of magnefia unites eafily 
with phofphat of ammoniac, forming together a triple 
combination, quite infoluble. Fourcroy defcribed its 
properties in a calculus taken out of the colon of a horfe, 
which died at the veterinary fcliool at Alfort. 
Phosphat of Glucine.— An infoluble fait is form¬ 
ed by the combination of this earth with phofphoric 
acid; pour into a folution of fulphat of glucine a folu¬ 
tion of phofphat of foda without excefs of alkali; aplen- 
tiful mucilaginous precipitate is formed, with no tafte, 
very foluble in an excefs of phofphoric acid, and even in 
a foreign acid. This fait is decompofed by the fulphuric 
acid; and by the earths and alkalis, except alumine and 
zircon. It melts into a vitreous pearl under the blow¬ 
pipe, and keeps its tranfparency when cold. 
Phosphat of Alumine —This fait, like the pre¬ 
ceding, is but little known : it is prepared by a dire£t 
combination of alumine with phofphoric acid. It melts 
with the blow-pipe into a tranfparent glafs, and without 
being decompoled. It is almolt infoluble in W'ater, but 
becomes abundantly fo by an excefs of acid. It is de¬ 
compofed by the mineral acids; and by earths and alka¬ 
lis, except zircon. 
Phosphat of Zircon.— Of the nature of this fait 
very little is at prefent underftood ; we know only, that 
the phofphoric acid decompofes muriat of zircon, and 
forms with its bafe an infoluble compofition, which is 
precipitated in white flakes. 
Phosphat of Silex. —This fait is as little known as 
the preceding. Fourcroy fays, that, by uniting pliol- 
phonc acid with filex by fufion, this ialt is obtained, 
but whole properties have not yet been defcribed. By 
this method factitious jewels may be made. 
Of PHOSPHITS. 
Phofphits have many properties in common with phof¬ 
phats. The phofphits of foda and potaffi are eafily folu¬ 
ble in water, and cryftallizable 5 thole of lime, magne¬ 
fia, and barytes, are but little fo; but the phofphit of 
alumine enjoys this property in a very remarkable man¬ 
ner. Tliofe phofphits which are infoluble in themfelves 
become abfolutely foluble by an excefs of their acid. 
All, except perhaps that of barytes, are decompofed by 
lime. Yet thefe falts exhibit phenomena by which they 
may be eafily diftinguiflied from phofphats, and from alt 
other fubftances of this clafs. Thefe are chiefly, fur- 
niffiing by diftillation a fmall quantity of phofphorus, 
and of giving a bright flame when heated under the 
blow-pipe, even upon an incombultible Iubftance 
Thefe falts poflefs, in common with other falts, the pro¬ 
perty of precipitating gold from its folution in the me¬ 
tallic ftate, and of detonating by permiffion with the 
fuper-oxygenated muriat of potaffi. There are feven. 
phofphits which are perfectly known, from the experi¬ 
ments of Fourcroy and Vauquelin: thefe are, the phof¬ 
phits of potaffi, foda, ammoniac, lime, barytes, magne¬ 
fia, and alumine. 
Phosphit of Potash. —This fait cryftallizes very 
readily by cooling, w'hen the water in which it is dii- 
folved is fufficiently evaporated. Its form appears to be 
a four-fided prilm, terminated flopewife. Its tafte is 
flightly penetrating. It is very foluble. Heated with 
the blow-pipe, it iwells, and melts, without emitting, 
like the other phofphits, phofphoric light. It is collect¬ 
ed, by melting it, into a tranfparent globule which cry» 
3 T ftallizes. 
