121 
L A M 
the latter amounted only to 718, for the lighting of which 
oil Of rape-feed was employed. In Caffef, the ftreets be¬ 
gan to be lighted, under the landgrave Charles, in 1721; 
but, as regulations were not made fufficient to fupport 
this improvement, it was dropped. It was however re¬ 
vived in 1748 ; and in 1778 the number of the lamps was 
increafed to 1013, hefides thofe at the landgrave’s palace. 
Hanover was lighted in 1696, Halle in 17,28, and Gottin¬ 
gen in 1735. Brunfwick, (incei765, has had 1565 lamps. 
Zurich has been lighted (ince 1778, but the lamps are 
very few in number. 
Though we mention London the laft, it was next to 
Paris (fome fay before it) in adopting this ufeful inven¬ 
tion. In the year 1668, when feveral regulations were 
made for improving the ftreets, the Londoners were re¬ 
minded that they fliould hang out lanterns duly at the ac- 
cnjlomed. time. In the year 1690 this order was renewed, 
and every houfekeeper was required to hang out a light, 
or lamp, every night, as foon as it was dark, between Mi¬ 
chaelmas and Lady-day; and to keep it burning till the 
hour of twelve at night. In the year 17x6 it was ordered 
by an aft of common council, that all lioufekeepers, 
whofe houfes fronted any ftreet, lane, or public paflage, 
(hould, in every dark night, that is, every night between 
the fecond night after every full moon and the feventh 
night after every new moon, fet or hang out one or more 
lights, with fufficient cotton wicks, that ftiould continue 
to burn from fix o’clock at night till eleven o’clock of the 
fame night, under the penalty of one (hilling. All thefe 
regulations, however, feem to have been ineffeftual, owing 
to bad management. The city was lighted by contraft, and 
the contraftors for liberty to light it were obliged to pay 
annually to the city the fum of fix hundred pounds. Be- 
fides, the contraftors received only fix (hillings per annum 
from every houfekeeper whofe rent exceeded ten pounds; 
and all perfons who hung out a lantern and candle before 
their houfes were exempted from paying towards the pub¬ 
lic lamps. The ftreets were lighted no more than a hun¬ 
dred and feventeen nights, and then for only five hours 
each night; and, as this left great opportunity to thieves and 
robbers to commit depredations, the lord-mayor and com¬ 
mon-council judged it proper, in the year 1736, to apply 
to parliament for power to enable them to light the ftreets 
of the city-in a better manner; and an aft was accord¬ 
ingly paffed, by which they were empowered to ereft a 
fufficient number of fuchfortof glafs-lamps as theyfliould 
judge proper, and to keep them burning from the fetting 
to the rifing of the fun throughout the year. Inftead, 
therefore, of a thoufand lamps, the number was now in¬ 
creafed to 4.679 ; but, as even thefe were not fufficient, 
feveral of the wards made a confiderable augmentation, fo 
that the whole could amount to no lefs than 5000. This, 
however, was not the amount of all the lamps in London, 
but of thofe in what is properly called the city and liber¬ 
ties. As this divifion forms only a fifth part of Lon¬ 
don, Maitland reckons the whole number of public 
and private lamps to have been, even at that period, 
upwards of 15,000. In the year 1744, owing to the 
great number of robberies committed in the ftreets during 
the night, it was found neceflary to apply for another aft 
of parliament to regulate dill farther the lighting of the 
city; and at that period this eftablilhment was placed upon 
that footing on which it now (lands. The lamps of Lon¬ 
don, at prefent, are all of cryftal glafs ; each is furniftied 
with three wicks ; and they are affixed to irons placed 
againft the houfes at the diftance of a certain number of 
paces from each other. They are lighted every day in 
the year at fun-fet; and Oxford-ftreet alone is faid to 
contain more lamps than all Paris. Beckman's Hijl. of In¬ 
ventions, vol. iii. Repertory of Arts, vol. iii. xiv. xviii. 
xxi. 
LAMP-BLACK, f. A pigment of which there are two 
forts; one of which is the light foot obtained from burn¬ 
ing pine and other refinous wood ; the other, which is 
the heavy black, is obtained by calcining bones in clofe 
Vol. XII. No. 816. 
LAM 
veflels. For the preparation, fee the article Pigment. 
Subftances painted with, lamp-black and oil are found to 
refill the effefts of eleftricity to a furprifing degree; fo 
that in many cafes even lightning itfelf feems to have been 
repelled by them. 
LAMP-FUR'NACE, f. A furnace, in which the heat 
is produced and maintained by the flame of a lamp intro¬ 
duced within it. This furnace has no occalion for an 
afh-hole, a grate, or a fire-place. It has only one opening 
below, through which the lamp is introduced, and a kind 
of ('mail chimney in its upper and lateral part, for circu¬ 
lation of air, to keep up the flame of the lamp, and to 
give venttothefmoke. The following account of a lamp- 
furnace, invented by Robert Perceval, M.D. M.R.I.A. 
is extracted from the Tranfaftions of the Royal Irifli Aca¬ 
demy. It conlifts of a cylindrical bod}', A, fig. 11 and 12, 
4s inches diameter, and 9^ high, furmounted by a labo¬ 
ratory, (or fpace for containing veflels,) which is a hol¬ 
low truncated cone, B, 6£ inches wide at top, and 4! at 
bottom. Its conical (hape adapts it to veflels of different 
fizes. To the infide of the laboratory are riveted fix tubes, 
C C C, §ths of an inch diameter, on which the veffel refts, 
fo that lpace fufficient for the paflage of heated air is in- 
terpofed between it and the infide of the laboratory. 
Into three of thefe tubes, iron fpikes (previoufly fitted to 
them) are occalionally introduced; two of them are feen 
in fig. x 1, marked D D : their coverging extremities form a 
fupport for veflels the bottoms of which are lefs than 4^ 
inches in diameter. In one of thefe tubes, whilft the 
lamp is burning, is placed the fmall pipe (flown feparately 
at A, fig. 13 ; which, communicating with the refervoir B, 
fupplies oil gradually to the lamp, through an aperture 
contrived for that purpofe. The lamp, which is contained 
in the body of the furnace, is made according to Argand’s 
conltruftion, with an oil-ciftern, which is a hollow "cylin¬ 
der. The diameter of the wick-holder, in the clear/ is 1 
inch £; the diameter of the circular air aperture within E,fig. 
12, is 1 inchf. The lamp is lupported by two crofs-llays F F, 
which are fixed to the top of the tube G. This tube rifes 
and falls on the (tern H, and is fixed at different heights 
by means of the fpring-catch I, which is faftened to the 
tube, and fits into holes made in the Item. The tube, in 
rifing and falling, carries with it the lamp, which, by this 
means, may be lupported at different diftances from the 
veflels, in the laboratory. The furnace itfelf anfwers the 
purpofe of a chimney to the lamp. In the body of the 
furnace is an opening K, fig. 11, for trimming the lamp ; 
this may be clofed by a Aide. When it is doled, the heat 
of the lamp is confiderably increafed, for reafons too ob¬ 
vious to be infilled upon. The bottom of the lamp, to 
make it more (leady, is loaded with lead. 
“ I was employed in making fome experiments with 
this lamp, aflifted by my ingenious friend Mr. Healy, 
when he luggefted that the heat produced would probably 
be greater, if the internal air-aperture of the wick-holder 
were diminiflied. This conjefture I thought probable, as, 
in the date of the lamp which I have deferibed, the cen¬ 
tral air was fo far removed from the flame as not to be 
heated confiderably by it; and this, we imagined, might 
counterbalance any advantage which might refult from 
the more liberal fupply of air to the flame. To deter¬ 
mine whether this was really the cafe, we caufed a Hopper 
to be made, half an inch in diameter, which, fitting into 
the central aperture with a fpring, left a circular opening 
of only § of an inch wide, inftead of 1^ inch, for the pal- 
fage of air.” This was attended with advantage in the 
fucceeding experiments, and the aperture was afterwards 
reduced to ^th, of an inch, and (till with increafed ac¬ 
tion; “thus it appears (concludes Dr. P.) that, in lamps 
made on this conllruftion, the internal aperture for air 
may be confiderably diminiflied- with advantage. What 
is the moft advantageous opening, I have not had leifure 
precifely to determine ; but it is probable that it would 
not bear to be diminiflied much more than in the experi¬ 
ment laft recited.” 
I i 
LAM'PA, 
