114 L A 
part of this performance he attempts to refute the ovarian 
hypothecs of generation. Asa writer in furgery, he made 
himfelf known by his Traite complet de Chirurgie, 3 vols. 
i2mo. 1722, feveral times reprinted: the belt edition is by 
Sabatier, 2 vols. 8vo. 1771. This work does not quite 
anfwer to its title, fince feveral difeafes belonging to chi- 
rurgical practice are omitted; but it is a very ul'eful col¬ 
lection of fails and obfervations in fome of the molt im¬ 
portant cafes. Eloy. Ditt. Hijt. de la Med. 
LAMP,yi [ lampe , Fr. lampas, Lat.] A light made with 
oil and a wick.—In /aw/>-furnaces I ufe fpirit of wine in- 
Itead of oil; and the fame flame has melted foliated gold, 
Boyle. 
O thievilh ni.ght, 
Why fliould’ft thou, but for fome felonious end. 
In thy dark lanthorn thus clofe up the ftars 
That nature hung in heaven, and fill’d their lamps 
With everlafting oil, to give due light 
To the milled and lonely traveller ? Milton. 
Any kind of light, in poetical language, real or metaphorical: 
O may thy filver lamp from heaven’s high bow’r 
TireCt my footfteps in the midnight hour. Gay. 
Lamps were in general ufe amongft the Jews, Greeks, 
and Romans. The candleftick with feven branches, 
placed in the fanftuary by Mofes, and thofe which Solo¬ 
mon afterwards prepared for the temple, were crylta! glades 
filled with oil, and fixed upon the branches of the candle- 
flick. The lamps or candlefiicks made ufe of by the Jews 
in their own houfes were generally put into a very high 
ftand on the ground. The lamps fuppofed to be uled by 
the foolilh virgins, &c. in the gofpel, according to critics 
and antiquaries, were a fort of torches, made of iron or 
potters’ earth, wrapped about with old linen, and moift- 
ened from time to time with oil. Malth. xxv. 1, 2. The 
lamps of Gideon’s foldiers were of the fame kind. Jud. vii. 
j 6. The ufe of wax was not unknown to the Romans, 
but they generally burnt oil; hence the proverb, Tempus 
et olevm perdidi, “ I have loft my labour.” Lamps were 
fometimes burnt in honour of the dead, both by Greeks 
and Romans. 
The ufe of lighted lamps in churches, and places of de¬ 
votion, is very ancient. In the city of Fez is a mofque, 
wherein are nine hundred brazen lamps burning every 
night. In Turkey, all the illuminations are made only 
with lamps. Polydore Virgil aferibes the firft invention of 
lamps to the Egyptians ; and Herodotus deferibes a feaft 
of lamps held annually in Egypt. 
Kircher (hows the manner of preparing lamps, which 
Ihall diffufe a light fo difpofed, as to make the faces of 
thofe prefent appear black, blue, red, or of any other 
colour. 
There has been a great difpute among the learned about 
the fepulchral lamps of the ancients: fome maintain, they 
had the fecret of making lamps that were inextinguiftia- 
ble, alleging feveral that have been found burning, at the 
opening of tombs fifteen or fixteen hundred years old. 
But others treat thefe relations as fables; and others think, 
that the lamps, which were before extinguilhed, took 
light afrelh upon the admiftion of frefh air. Dr. Plott, 
however, is of opinion, that fuch perpetual lamps are things 
practicable, and has himfelf made fome propofals of this 
kind. The linum albeftinum, he thinks, may do pretty 
well for the wick; and that the naptha, or liquid bitumen, 
conftantly fpringing into fome of the coal-mines, would 
anfwer for the oil. If the afbeftos will not make a per¬ 
petual wick, he thinks there is no matter in the world 
that will; and argues, that the tradition of fuch lamps 
mull be fabulous, or elfe that they made them without 
wicks. Such a lamp he thinks it pofiible to make of the 
bitumen fpringing into the coal-mines at Pitchford in 
Shropfnire; which, he fays, like other liquid bitumen, 
will burn without a wick. Thofe lamps that kindle on 
the immillion of frefli air, the fame author thinks, might 
M P. 
be imitated by inclofing fome of the liquid phofphorus in 
the recipient of an air-pump; which, under thofe circum- 
ftances, will not Urine at all; but, on letting the air into 
the recipient, there will poflibly, fays he, appear as good- 
a perpetual lamp as fome that have been found in the fe- 
pulchres of the ancients. 
The moft litriple lamp confifts of a veflel of almoft any 
drape, containing oil or acohol, with a tube projecting a 
little above the l'urface of the liquid, and containing any 
fibrous fubftance capable of raifing the liquid to the top 
of the tube, by capillary attraction. The oil, thus raifed 
and diffufed through the fibrous fubftance, is fo detached 
from the main body of the liquid, as to admit of being 
heated to a temperature fufficient to volatilize the oil, the 
vapour of which, in a ftate of combuftion, conftitutes the 
flame of the lamp. In the management of the lamp of 
the moft fimple kind, fo far as relates to the fupply of oil, 
three things are neceflary to be obferved. 1. The wick 
muft be of fuch a fubftance as heft to promote capillary 
attraction. 2. It fhould not be twilled too much, ini 
which cafe its capacity for the oil is too little; nor 
fnould it be fo loofe as to dimiirifh materially its ca¬ 
pillary attractive power. This is frequently the cafe, 
when the wick has been too long immerfed in the oil. 3. 
With regard to the diftance of the flame from the furface 
of the oil; if the flame be too near the furface, a fmaller 
quantity of oil will acquire the intenfe heat neceflary to 
raife it into vapour, fince the heat communicates with the 
fluid. On the contrary, when the flame is too high above 
the oil, the capillary attraction, which decreafes in fome 
ratio of the diftance, is infufficient to fupply the neceflary 
quantity of oil. Experience has long ago eftablilhed, that 
cotton is the belt medium for the tranfmillion of the oil, 
which is prepared in a particular way for the purpofe. 
During the flow combuftion of oil, as obferved in the 
common lamp, as well as that of tallow in candles, the 
fatty matter is decompofed, producing a quantity of va¬ 
pour which inflames in contaCt with oxygen ; and a cloudy 
exhalation in the form of fmoke, confilting of numerous 
fmall particles of carbonaceous matter, which, if collect¬ 
ed, conftitute the article called lamp-black. Befides the 
offenfive fmell and appearance of this fubftance, there is 
an evident wafte of combuftible matter, capable of pro¬ 
ducing both light and heat. 
Cardan’s Lamp, is a contrivance of an author of that 
name, which furnilhes itfelf with its own oil. It confifts 
of a little column of brafs, tin, or the like, well clofed 
every where, excepting a fmall aperture at bottom, in the 
middle of a little gullet or canal, where the wick is placed. 
Here the oil cannot get out, but in proportion as it waftes, 
and fo opens the paflage of that little aperture. This 
kind of lamp was much in ufe fome years ago; but it has 
feveral inconveniences ; fuch as that the air gets into it 
by Harts and gluts; and that, when the air in the cavity 
comes to be much rarefied by heat, it drives out too much 
oil, fo as fometimes to extinguifli the lamp. Dr. Hook, 
and Mr. Boyle, have invented other lamps that have all 
the conveniences of Cardan’s without the inconveniences. 
The flame in a lamp never confumes the wick, till the 
wick be expofed to the air by the flame’s falling down¬ 
ward ; and from thence it ma}' be inferred, that a way 
found out to keep the fuel, and confequently the flame, 
at the fame height upon the wick, would make it laft a 
long time. Many means have been dqvifed to arrive at 
this; but it feems only poflible to be done, in any degree 
of perfection, by hydroftatics. Thus, let a lamp be made 
two or three inches deep, with a pipe coming from the 
bottom almoft as high as the top of the veflel; let it be 
filled fo high with water as to cover the hole of the pipe 
at the bottom, to the end that the oil may not get in at 
the pipe, and fo be loft. Then let the oil be poured in, 
fo as to fill the veflel almoft brimful, which muft have a 
cover, pierced with as many holes as there are wicks de- 
figned. When the veflel is thus filled, and the wicks are 
lighted, if water falls in by drops at the pipes, it will al- 
