270 
P H L 
7. Phleum geniculatum, or bent cat’s-tail grafts: ftpike 
nearly ovate; glumes fringed; Hera bent at the joints. 
Gathered by Dr. Bellardi on Mount Cents, in barren 
ground. Root perennial, not bulbous. Stems a fpan or 
more in height, with three or four bent joints. 
8. Phleum Africanum, (Loureiro,) a very different fpe- 
cies from Phleum pratenle. 
9. Phleum arenarium. See Phalaris arenaria. 
10. Phleum Cochinchinenfe. Probably a fpecies of 
Pa (pal um. 
11. Phleum Schoenoides. See Crypsis. 
Propagation ami Culture. See Grass. 
PHLI'AS, in ancient geography, an ifland fituated in 
the environs of Altolia. 
PHLI'US, now Staphilica, a town of Sicyonia, on the 
river Afiopus, fouth-weft of Theranda. It was confider- 
able in the time of Paufanias, though it had fuffered much 
during the war of Achaia. In the midft of this place was 
a brazen goat, to which the Inhabitants paid great refpeft. 
This worfhip, without doubt, began, when the country, 
thinly inhabited, found itfelf expofed to the deftruftion 
and lofs of their vineyards by the ravages of the wild 
goats, with which the mountains abounded. The Phli- 
ufians, having lolt fight of the original inftitution of this 
worfhip, pretended, that the conftellation of the goat, or 
Capra, afforded nourifhment to their vines, and that from 
this circumftance originated the worfhip of the goat. 
They pretended that their town was the centre, or 
“ Omphalos,” of the Peloponnefus. The town and citadel 
were adorned with many monuments. Ganymede or 
Hebe, for thefe were names of the fame divinity, had a 
temple in this place, which was regarded as a facred 
afylum. They had here alfo a temple of Ifis, who was 
regarded as the proteftrefs of navigation. 
Phlius, a maritime town of the Peloponnefus, in the 
Argolide, fituated between Nauplia Navale and Hermoine. 
Here were a cavern and a labyrinth. 
PHLOGIS'TIC, aelj. [from phlogijlon.'] Partaking of 
phlogifton.—Thefe bodies are called phlogifiic bodies. 
Adams. 
PHLOGIS'TON, f. [from <pxiyu, Gr. to burn.] A 
chemical liquor extremely inflammable. The inflammable 
part of any body.—The doflrine of pliilogijlon, as under- 
ftood by modern chemifts, implies, that a quantity of fire, 
or the matter of light and heat, is occafionally contained 
in bodies, as part of their compofition. Adams. 
The following fummary will be found an ufeful addi¬ 
tion to what has been faid underthe article Chemistry, 
vol. iv. p. 182 to 1 83 , on the fubjefl of caloric , or the 
matter of heat. 
Every fubftance capable of combuftion was fuppofed, 
by the old chemifts, to confift of a certain incombuftible 
part, called a bafe, united to phlogijlon ; and the pheno¬ 
mena of combuftion were cccaftoned only while the phlo¬ 
gifton was prelent. Sulphuric acid, for inftance, was 
confidered as a Ample body, which, when united with 
phlogifton, conftituted fulphur. On the other hand, the 
fulphur, during combuftion, loft its phlogifton, and be¬ 
came fulphuric acid. The metals were confidered as 
earths united to phlogifton, while the oxyds were confi- 
dered as Ample bodies. To conceive the true meaning 
to be given to this imaginary body, we have only to con¬ 
ceive it prefent where oxygen is abfent, and vice verfd. 
Nothing more was wanting to (liow the fallacy of the 
phlogiftic theory, than weighing the products in which it 
was luppofed to be prefent. When a body was faid to 
have combined with phlogifton, it became juft fo much 
lighter as was equal to the oxygen now faid to be fepa- 
rated, and the contrary. 
The procefs of combuftion, to an account of which 
we havejuft referred, is unqueftionably one of the moft 
ftriking, as well as the moft familiar, of natural pheno¬ 
mena. It has for ages engaged, and ftill engages, the at¬ 
tention of philolophers. We {hall endeavour to Ijate, as 
briefly as pcfllble, the three hypothefes of modern times 
P H L 
on the fubjed. The firft is the phlogiftic theory of Stahl, 
which fuppofes that all inflammable bodies, or fuch as 
throw out light and heat during theircombuftion,contain 
a portion of fubftance that is at once intangible and im¬ 
ponderable; this is the phlogifton to w'hich they owe 
their inflammability. While a body is burning, it parts 
with its phlogifton, which combines with the furround¬ 
ing air, and by this means it is reduced to an a(h, or, 
if it be a metal, to a calx or oxyd : both the afh and the 
oxyd differ from the original fubftances, whether they be 
wood, coal, iron, Sic. in being merely deprived of their 
phlogifton. Hence, referring to metal for an example, in 
order to reduce an oxyd to the metallic (late, it is necef- 
fary to unite it with fome inflammable fubftance, as char¬ 
coal, w'hich yields it phlogifton. 
The difeovery of dephlogifticated air, or oxygen gas, 
by Dr. Prieftley, gave rife to the theory of Lavoifier. 
This philofopher demonftrated, that in all cafes of com¬ 
buftion the inflammable fubftance united with oxygen, 
and produced either an acid, an oxyd, or water, or a mix¬ 
ture of the three,and that the weight of the produfl above 
that of the Ample combuftible was equal to the quantity 
of oxygen that had difappeared. This has been efteemed 
as an improvement oraddition to Stahl’s hypothefts, by 
accounting for the increafe of weight of the product.of 
combuftion above that of the combuftible body. But 
combuftion implies, as we have feen, the difengagernent 
of light and heat, which is accounted for by LavoiAer, by 
fuppoftng oxygen gas to be a compound made up of that 
intangible fubftance oxygen with heat and light. Ac¬ 
cording to this theory, a body, while in the aft of burn¬ 
ing, abforbs oxygen from the air, feparating it from the 
heat and light with which it was united, and which, efca- 
ping, then appears in the feparate form of fire. Hence 
the difference between combuftion and flow oxygena¬ 
tion is Amply this; that, in the former cafe, the procefs 
advancing rapidly, the heat and light feparated from the 
oxygen gas appear in the lhape of flame, and in the lat¬ 
ter they efcape fo flowly as to be imperceptible to the 
fenfes. 
There feems fcarcely any doubt that the heat given out 
during combuftion is derived from the oxygen gas, becaufe 
the increafe of temperature is found to be accurately 
proportioned to the quantity of oxygen confumed. 
There are, however, feveral objeftions that oppofe the 
fuppofition that light is alfo a conftituent part of oxygen 
gas; of thefe, one of the ftrongeft is, that the quantity 
of light given out in the procefs is not proportioned to 
the quantity of heat; and the circumftance of the various 
colours which the flame affumes, according to the nature 
of the burning body, would lead one to infer that it is 
the burning body, and not the oxygen gas, which is the 
principal fource of the light. This is the third theory, 
efpoufed by M. Gren, Dr. Thompfon, and others; 
and, according to this, the procefs of combuftion is a 
double decompofition, in which the combuftible body 
unites with oxygen to form an oxyd, or water, or an 
acid, according to circumftances, while the light of the 
combuftible body combines with the caloric of the oxy¬ 
gen, and produces flame. This fyftem bears a refem- 
blance to that of the phlogiftic theory, becaufe the one 
and the other fuppofe fomething to be contributed by the 
combuftible body towards the compofition of the fire. 
There are however many difficulties attached to it, that 
require experiments to explain and confirm. Sir Hum¬ 
phrey Davy has indeed, by his inveftigations, been led 
almoft to conclude that there exifts a diltinft inflammable 
principle, which pervades the whole of nature, which 
would bring us back, in part at leaft, to the phlogiftic 
theory. See Prieftley’s Doftrine of Phlogifton eftablifhed, 
1803. and Thompfon’s Syftem of Chetniftry, vol. i. 
PHLOGOT'ICA, or Inflammatory Difeafes, Seethe 
article Pathology, vol. xix. p. 227, & feq. 
PH.LO'MIS, J'. [derivation unknown.] Jerusalem 
Sage, &c. in botany, a genus of the clafs didy namia, order 
gymnofpermia, 
4 
