254 C H E M 
ftallizes, and becomes opaque by cooling. It is decom- 
poled by lime and barytes, which produce copious pre¬ 
cipitates in a folution of this lalt. The fulphuric, nitric, 
and oxalic, acids, &c. feparate the pholphorous acid from 
its alkaline bafe, the oxygenated muriatic acid converts 
it into a pholphut. It con (ills of potafli, 49-424; phof- 
phorous acid, 39-466; water, ii-iio. 
Phosphit of Soda. —This is very foluble in water, 
requiring in the ordinary temperature of the atmofphere 
only two parts of that liquid to dilfolve it. Its folution, 
when fubjeftedto a flow evaporation, exhibits at firlt on 
the tides of the capfules, fmall plumofe cryltals like thofe 
of lal-ammoniac; afterwards fquare laminae are formed 
on the furface of the liquor, which leemed to be formed 
by the union of four triangles. Some portion of this fait 
affume the form of the pappus, or down, of fouie vegeta¬ 
ble feeds ; but, in examining thefe with a good glal's, 
they appear to be compofed of a great number of fmall 
cubes, which come very clofe together, but do not 
unite, for we can ealily lee the fpace which feparates 
them. It decrepitates with the biow-pipe, and gives 
out a phofphorefcent flame. It then melts into a glafs, 
which l'preads on the fupport, and becomes opaque by 
cooling. This fait confifts of foda, 23-680; pholphorous 
acid, 16-320; water, 6o-ooo. 
Phosphit of Ammoniac. —This has a very ftrong pe¬ 
netrating tafte. It creeps up the fides of the veffels in 
which it is evaporated. It cryftallizes in the form of very 
long fine ti-anfparent needles, fo that it is difficult to 
determine, by the fight alone, the form and the relation 
of its angles. It boils up and fwells with the blow-pipe, 
giving out, after a fewleconds, a great quantity of phof- 
phorated hydrogen gas, which inflames in the air, and 
forms very beautiful circles of white fmoke. Tills ex¬ 
periment proves, that phofplaorus, in a high tempera¬ 
ture, when afhfted by the prefence of ammoniac, poffef- 
fes the property of decompofmg water. The oxygen of 
the water, combines with one portion of this inflammable 
iubftance, and its hydrogen with another portion, to 
form phofphorated hydrogen gas, which inflames as 
foon as it comes into contact with the air. It is decoi-n- 
pofed by diftillation in a retort. The ammoniac is dif- 
engaged partly in a liquid ftate, and partly in the ftate 
©f a gas, which retains phol'phorus in folution, but which 
does not inflame. It gives out a phofphorefcent light, 
when mixed with oxygen gas. What remains in the re¬ 
tort is vitreous pholphoric acid. It is decompoled by 
potafli, l'oda, lime, and barytes; for the folutions of 
thefe earths occafion a copious precipitation in that of 
pholphit of ammoniac, A Itrong fmell of ammoniac is 
perceived during the action of the fixed alkalis. It pre¬ 
cipitates nitrat of mercury, of a white colour, but the 
pholphit of mercury which refults, foon becomes of a 
grey colour, particularly the part which is expofed to 
the light. It conlifls of ammoniac rifty-one ; acid, twen¬ 
ty-fix; water, twenty-three. 
Phosphit of Lime. —The phofphorous acid forms 
with lime a very intimate combination, which is very 
infoluble in water, and which has no perceptible tafte. 
It is rendered foluble by an excels of acid, and this tri¬ 
ple union affords fmall hard and brilliant cryltals, by a 
careful evaporation. Thele cryftals are too fmall to ena¬ 
ble us to determine their form. The phofphorous acid, 
appears to adhere ftrongly to the pholphits of lime, for it 
isimpoffible to, feparate it by frequent walkings with wa¬ 
ter. This excefs of acid is taken from it by all the earthy 
and alkaline fubftances, although thefe have for the phoi- 
phorus acid lei's affinity than lime, which feems to prove, 
tfiat the acid in this combination is retained by two dif¬ 
ferent forcis. It melts with the blow-pipe, emitting a 
phofphorefcent light, and forming into a globule, the 
tranfparency of which remains after cooling. Its fulion 
is promoted by an excefs of acid, and the glafs which it 
affords is more tranfparent. Lime feems to have, of all 
fubftances, the ftrongeft affinity for phofphorous acid. 
I S T R Y. 
It is decompofed by the mineral, and even by feme of 
the vegetable, acids, fuch as the oxalic, citric, tartaric, 
&c. It confifts of lime, fifty-one; acid, thirty-four; 
water, fifteen. 
Phosphit of Barytes. —This is difficultly foluble 
in water. Lime water forms with the folution however, 
an evident cloud. The folubility of this l'alt, is greatly 
increafed by an excefs of acid, fo that it affords by lpon- 
t.meous evaporation fine needle-like cryltals, fo fmall in¬ 
deed, that it is impoflible to afcertain their exnCt form. 
The fait in this flare, has the fame habitudes with water, 
or the acidulous pholphit of lime. The oxalic acid 
forms in its folution a cryftalline depofit, compofed of 
fmall and long needles. Thefe cryltals are a combina¬ 
tion of ox,alic acid and barytes: ammoniac takes the ex¬ 
cefs of acid from the phofphit of barytes, which is pre¬ 
cipitated in the form of a white cloudy powder. This 
powder is foluble, like the pholphit of lime, in acetous 
acid, although this acid is unable to decompofe thefe 
fults-. Phofphit of barytes melts with the blow-pipe into 
a globule, which is covered with fo ftrong a light, that 
it is impolfible to look at for a few feconds without inju¬ 
ring the eyes. This globule, which is tranfparent du¬ 
ring fulion, becomes opake by cooling. With the ex¬ 
ception of lime, the earths and alkalis produce no change 
on this fait. The mineral and feveral of the vegetable 
acids decompofe it. It is compofed of barytes, 51-230 - r 
acid, 41-770; water, 7-000. 
Phosphit of Magnesia. —This fait is flightly folu¬ 
ble in water, without the afliftance of an excels of acid. 
It has no fenfible tafte, and effervefces in the air like phof- 
phat of magnefia. It fwells fuddenly with the blow-pipe;, 
inflames and emits a greenilh phofphoric.light: it melts 
into a globule, which acquires a milky colour by cooling. 
It is decompofed by the fixed alkalis, lime, and magne- 
fia. Ammoniac produces only a partial decompolition, 
and forms with it, as with ail other magnefian falts, a 
triple l'alt, poffeffmg peculiar properties. The fulpliuric, 
nitric, muriatic, fluoric, citric, oxalic, and tartarous, 
acids, decompofe it by difengaging its phofphorous acid. 
The oxygenated muriatic acid converts it into a phof- 
phat, by burning the fmall quantity of phofphorus which 
it contains. It confifts of magnefia, twenty; acid, forty- 
four ; water, thirty-fix. 
Phosphit of Alumine. —This is very foluble in wa¬ 
ter, without an excefs of acid, in which it differs from 
the phofphat, which is infoluble, and which becomes lo 
only by an excefs of acid. Evaporated with a gentle 
heat, it exhibits no mark of cryftallization, no faiine de- 
polit; on the contrary, it forms a tranfparent duCtile 
niafs, which has a ftrong refemblance to a left gum. This 
fait has an aftringent taite. Placed on burning charcoal, 
it fwells up like alum, and emits a beautiful pholphonc 
light. It preferves the volume it acquired in fwelling, 
and becomes very light and fpongy. It does not attract 
humidity from the air, but remains dry and tranfparent. 
Alumine has the weakeft attraction of alkaline and earthy 
matters, for pholphorous acid, fo that is ealily decom¬ 
poled. The greater part of acids decompofe it. Vauque- 
lin remarks, that were we to judge by analogy of the 
properties of compound fubftances, we fliould be led to 
believe, that the phofphits mult be very combultible, as 
they contain a portion of unburnt phofphorus, which 
has fo ftrong an attraction for oxygen, that it will unite 
with it in every temperature. But this is contrary to 
obfervation ; for the phofphits remain for months, either 
in the liquid or folid ftate, without undergoing the final-, 
left alteration'. Sulphits, on the contrary, are in the fame 
circumftances foon changed into fulphats. He ingeni- 
oully accounts for this difference,in the following manner. 
The combuftion of a body takes place more ealily and 
fpeedily in conjunction with other bodies, which increale 
its affinity. It is in this way that metals dilfolve much 
more rapidly in water mixed with an acid, than they do 
in pure water. It is on the lame principle, that the nitric 
