292 ]? H 0 
at prefent known. It reddens vegetable blues. It com¬ 
bines with ammonia, condenfing four times its bulk of 
that gas, and forming a peculiar neutral fait. Phofgene 
gas is decompofed by water, and by molt metallic bodies. 
It is an acid of a very peculiar nature, and deferves a 
much more complete examination. As this gas has been 
hitherto produced only by the aftion of light, Mr. Davy 
propofed to name it pliofgene. See the Phil. Tranf. for 
1812. Part I. 
PHOS'PHATE, f. A faline body compofed of phof- 
phoric acid united to lome bale, as for inftance, lime, 
which is called phofphate of lime. 
PHOS'PHITE,/. A fait formed by the phofphorous acid 
combining with the bafe of the fait. For an account of 
the different phofphates, phofphites, and phofpluirets, 
fee the refpeftive bafes, and the Index to the article Che¬ 
mistry, vol. iv. 
PHOS'PHOR, or Phosphorus,/, [from the Gr. (pa;, 
light, and (pipa, to bring.] The morning ftar.—Why fit 
we fad when Phofphorus {bines fo clear; 1 Pope. —A chemi¬ 
cal fubitance which, expofed to the air, takes fire.— Phof¬ 
phorus is obtained by diftillation from urine putrified, by 
the force of a very vehement and long-continued fire. 
Pemlerlo)!. —Of lambent flame you have whole (beets in 
a handful of phojphor. Addifon. 
For the method of preparing phofphori, and for an ac¬ 
count of their combinations, and their medical and other 
properties, fee the article Chemistry, vol. iv. 
The acids formed by the combination of phofphorus 
with oxygen are of fo difficult inveftigation, that hitherto 
we are but imperfeftly acquainted with their compofition. 
But the fubjedf has lately attracted the attention of che- 
mifts in general ; and fo many perfcns have engaged in 
the invelligation, that it cannot much longer remain in¬ 
complete. Two very curious and important papers have 
oeen puhlifhed in the fecond volume of the Ann. de 
% Chim. et Phyf. the firft by M. Dulong, the fecond by Pro- 
feffor Berzelius. 
M. Dulong announces the exiftence of no fewer than 
•four acids compofed cf oxygen and phofphorus, one of 
which he has had the honour of difcovering himfelf. 
Thefe acids he diftinguiflies by the following names : 
flypophofphorous acid, phofphorous acid, phofphatic 
acid, and phofphoric acid. The fecond and fourth of 
thefe will be found noticed under the article referred to. 
It remains to make that article complete by explaining 
the compofition of the other two. 
Phofphatic Acid is obtained when phofphorus is al¬ 
lowed to burn (lowly in the open air. M. Dulong con- 
fidersit as a combination of phofphorous and phofphoric 
acids. According to him, it is always conllant in its 
proportions. He confiders it as compofed of, phofphorus 
ioo, oxygen 1i2’4. 
Hypop/ioJ'phorous Acid, which is a difcovery of Mr. 
Dulong’s, he obtained in the following manner. When 
phofphuret of barytes, of ftrontian, or of lime, is put into 
water, phofphureted hydrogen gas is difengaged, as is 
well known. The oxygen of the water decompofed 
unites to the phofphorus, and forms turn acids, the hypo- 
phofphorous and the phofphoric, both of which unite to 
the bafe. The phofphate formed is infoluble in w'ater, 
but the hypophofphite is very foluble. He treated phof¬ 
phuret of barytes in this manner; and by filtrating the 
liquid, feparated the phofphate of barytes. The liquid 
contained in folntion hypophofphite of barytes. The 
barytes was precipitated by means of fulphuric acid, and 
nothing remained after filtration but the hypophofphorous 
acid united to water. This acid poffeffes the following 
properties. It has a four talfe, and does not cryftallise. 
It may be concentrated by evaporation ; and in that cafe 
we obtain a vifcid liquid. When the heat is carried fur¬ 
ther, phofphureted hydrogen is driven off, a little phof¬ 
phorus fublimes, and pure phofphoric acid remains be¬ 
hind. It abforbs oxygen (lowly from the atmofphere. 
All the hypophofphites are very foluble in water. Thofe 
P H O 
of barytes and ftrontian cryftallize with difficulty, 'fhofe 
of potafli, foda, and ammonia, are very foluble in alcohol, 
Hypophofphite of potalh is much more deliquefcent than 
muriate of lime. According to the analyfis of Dulong, 
this acid is compofed of phofphorus ioo, oxygen 37’44- 
But he fufpects that it is a triple compound, and that it 
contains hydrogen. 
According to the moll recent determination of Dr, 
Thomfon, the weight of the atom of phofphorus is 15, 
that of phofphorous acid 25, and that of phofphoric acid 
3;. A good deal of doubt, however, (till hangs over this 
principle and its compounds. The hypophofphorous acid, 
difcovered by Dulong, appears to contain lefs oxygen 
than either the phofphorous or phofphoric acid, and was 
formerly confideredas the protoxyd, or firft compound of 
phofphorus and oxygen. Dr. T. however, is latterly 
difpofed to confider the hypophofphorous acid as a com¬ 
pound of 2 atoms phofphorus + 1 atom oxygen ; but this 
is by no means afcertained. We may alfo obferve, that 
all the beft analyfes of the phofphates (how that the 
weight of the atom of phofphoric acid lies between 40 
and 45. 
Within thefe few years, the old-fafhioned and teafing 
tinder-box has begun to be fuperfeded by phofphorus- 
bottles, or matches tipped with phofphorus inftead of 
fulphur. The phofphoric matches, or tapers, are prepared 
by the following fimple procefs. Take a glafs tube, four 
inches long, and one line in diameter, clofed at one end. 
Introduce a fmall quantity of phofphorus iqto the tube, 
and pufhit to its farther end ; after which, a taper covered 
with a fmall quantity of wax is introduced into the fame 
tube. The open end is then hermetically fealed, and the 
other end is plunged into boiling water; upon which the 
phofphorous melts, and fixes itfelf upon the match. A 
line is drawn at one end of the length of the tube, with a 
flint; that it may be broken, as occafion may require. 
The match is to be drawn out quickly to inflame the 
phofphorus. 
The procefs of M. Lewis Pegle for making the inflam-- 
mable bougies confifts in taking a glafs tube, five inches 
long, and two lines wide, one end of which is fealed with' 
a blow-pipe. Small tapers of wax are prepared with three 
double threads of cotton twifted together. The extre¬ 
mity of the match or taper is half an inch long, and mult 
not be covered with wax. A piece of lead is laid in a 
faucer filled with water; and upon this the phofphorus 
is cut, beneath the water, into fragments of the (ize of a 
grain of millet. One of thefe grains is to be dried, and 
introduced into the tube of glafs ; after which the for¬ 
tieth part of a grain of very dry fulphur is to be added, 
that is, half the weight of the phofphorus. One of the 
bougies is then taken, and its extremity dipped in very 
clear oil of wax. If too large a quantity rifes, it muft be 
dried with a cloth. The match is introduced into the 
tube with a turning or twilling motion between the fin¬ 
gers. The bottom of the tube muft then be plunged into 
boiling water to foften the phofphorns; obferving to 
keep it no longer than three or four feconds in the water. 
The other extremity of the tube is afterwards fealed. 
Thefe bougies muft be kept in a tin tube to avoid the 
danger of inflammation. 
Phofphoric bottles are formed by heating a glafs bot¬ 
tle, and fixing it in a ladlefull of (and; and then two or 
three fmall pieces of phofphorus are introduced into it. 
A fmall red-hot iron wire is ufed to ftir the phofphorus 
about, and caufe it to adhere to the internal furface of 
the bottle, where it forms a reddi(li coating. The heated 
wire is introduced repeatedly; and, when all the phof¬ 
phorus is thus diftributed within the bottle, it is left 
open for a quarter of an hour, and afterwards corked. 
When this is ufed, a common match tipped with fulphur 
is introduced into the bo,ttle, turned round, and quickly 
drawn out. The phofphorus which flicks to the lulphur 
takes fire, and lights the match.' The theory ot this phe¬ 
nomenon depends upon the circumftance, that the phof¬ 
phorus. 
