L X G 
would be little affected by wind or rain, (fee p.6Sj.) and 
would continue to burn as long as the fire was kept up 
round the retort; fo that the attendant would never be 
expofed to the weather, or have any motive for neglecting 
his duty; and the valuable products arifing from the co¬ 
king of the coal might form a part of his falarv or perqui- 
fites. We long to fee this ufefu! invention extended; for 
it was admitted by Boulton and Watt, who oppofed Mr. 
Winfor in his application to parliament, that the moft 
economical appropriation of the gas-light would be in 
furnifhing a large quantity of light within a fmall com- 
pafs or diftance. This therefore feems to be a cafe ex¬ 
actly in point; and we hope to fee the experiment tried. 
A Ample and ingenious plan has been propofed for the 
conltruCtion of light-houfes, which, if generally executed, 
might prove beneficial. The beacon confifts of a lantern 
made of call metal, in which there is a piece of clock¬ 
work, which makes the lamp turn round every two or 
three minutes, and exhibit different enlightened figures. 
The figures can be fo varied as to diltinguiih one light- 
houfe from another, and to prevent the poifibility of mil¬ 
taking the light of a lime-kiln, or accidental fire, for that 
•off a "beacon. The projector, Mr. Farmer, alio recom¬ 
mends, as a fubffitute for light, in foggy weather, a buoy, 
Similar in form to a life-boat, on which is fixed a beli of 
confiderable magnitude and powerful tone, which the mo¬ 
tion of the buoy, occafioned by the undulation of the fea, 
will keep perpetually ringing. The buoy may be placed 
at any convenient diftance from the mouth of the har¬ 
bour; or the mechanifm in the beacon might be fo con- 
ftrufted as to caufe a bell to ring, or a bafs drum to beat, 
in hazy weather. By placing a buoy or boat of the above 
defeription on a funken or dangerous rock, in any part of 
the fea, the mariner might be warned by the alarm-bell to 
keep at a proper diftance. 
The ufual mode of ereCting a light-houfe is to raife it 
apon iron pillars, funk either in a natural rock, or in other 
Hone-work, or upon piers funk in the earth, as the cafe 
may be. Thefe pillars, being often totally or in part co¬ 
vered by the fea, are liable to corrofion from the aCtion 
<?f fait water. To obviate this, inconvenience, Capt. Bro- 
die has invented a method of connecting together feveral 
fmall iron bars, and of coating them with lead, fo as to 
form f'olid pillars that will not be fubjeCt to corrofion. 
For this and fome other marine improvements, the gold 
medal of the Society of Arts was voted to him in May 
1804; and the method of connedting the iron bars or rods 
is Ihown at the bottom of the preceding.plate. A, fig! 10, 
is four rods of call iron, compofed of a number of pieces 
two feet long, rivetted together fo as to produce the effedt 
of one bar of the thicknefs of the whole. B, is a tube of 
oafl: iron, formed from a number of feparate pieces, each 
srbout ten inches long, and which, when placed round the 
iron rods above-mentioned, and then ferewed together, 
forms a mould, into which the melted lead is to be pour¬ 
ed, to coat the iron rods. C, a portion of the rods co¬ 
vered with the melted lead, fo as to form a cylindrical 
pillar apparently of lead, the iron being perfectly coated 
therewith. At fig. 11, D (hows the manner in which the 
hollow cylinder is formed to any length required, by the 
junction of a number of ferni-cylinders rivetted together 
and fitting each other. E, the fide-fianges ferewed clofe 
together. F, the end-flanges alfo ferewed together as pre¬ 
pared for the melted lead. After a certain portion of the 
iron rods are coated with lead, tiie lower parts of the tube 
are taken off and placed higher up; by which repeated 
changes, a few tubes will anlwer the purpofe to coat any 
length of the iron rods. 
LIGHT IN'FANTRY. See Infantry, vol. xi. p. 33. 
LI'GHT-LEGGED, adj. Nimble; fvy lit.-—Light-legged 
pas has got the middle fpace. Sidney. 
LIGHT-MENDED, adj. Unfettled ; unfteady.—He 
that is hafty to give credit is liaht-minded . F.ccl. xix. 4. 
LI'GHT-RO.OM, f. A fmall apartment, enclofed with 
glafs windows, near the magazine of a Ihip of war. It is 
. Vol. XII. No. S63. 
L I G 683 
ufed to contain the lights by which the gunner and his 
alfiltants are enabled to fill cartridges with powder to be 
ready for aCtion. 
LIGHT and SHADE, in painting. As light, when act¬ 
ing upon fubftantial forms, is always accompanied by flia- 
dow, and as they are neceflary adjuncts to each other, we 
(hall here unite them, and treat of them together. It is by 
the contrail of each to the other, that the efteCt of either is 
produced by colours; and, however paradoxical it may 
appear, it is neverthelefs true, that light in the art of 
painting is not more neceflary to produce Ihadow, than 
(hade is for the production of light. The colours which 
give the appearance of the former, obtain that effedt only 
when furrounded with darker ones, which conffitute 
Ihade; without the latter, they would appear nothing 
more than an uninterefting mafs of one plain tone, with¬ 
out any degree of the quality which is termed luminous ; 
but, contraffed by their oppofites in tone, they become 
brilliant; and, when form is fuperadded, obtain the cha¬ 
racter of light. The fame,’ though in the contrary de¬ 
gree, is the effedt of dark hues, which, without the con¬ 
trail of lighter ones, produce only a heavy, duil, unmean¬ 
ing, mafs, that merits not ihe appellation of (hac!e, till 
oppofed by other tones, and rounded into form by the 
afliffance of light. 
It was utterly impolTible that any arriff ffiould have at¬ 
tempted to imitate on a plain furface the appearances of 
round bodies, without difeovering the neceliity of lights 
and (hades. However, even this, which may be called 
natural chiaro-fcuro, was but very imperfectly underffcod 
till the time of Mafacci.o, near the middle of the fifteenth 
century ; the painters, prior to this period,, having had 
very little idea of what are called projecting (hadows ; 
fuch as are thrown upon one object, by another interven¬ 
ing between it and the rays of light. Indeed, in the 
pictures of moft of the old painters who preceded Leo¬ 
nardo da Vinci, the ground on which the figures (land, is 
made fo light on that fide where this projecting (hadovy 
fliould lie thrown, that they frequently feeni to have onlv 
air to lupport them. Leonardo da Vinci, towards the end 
of the fifteenth and the beginning of the fixteenth cen¬ 
tury, was the firlt who, in his admirable*-writings as well 
as in his pictures, treated the fubjeCt fcientifically ; but 
although the few remaining works of his pencil have pro¬ 
digious force, rotundity, and foftnefs, yet the fyftem 
which he recommends and generally adopted, of relieving 
the dark fide of his figures by a light back-ground, and 
the light parts by a dark one, prevented that expanfion 
and breadth of efteCt which the great Coreggio loon after 
difeovered could only he attained by a contrary inode of 
conduct, that of relieving one Ihadow by another itili 
darker, and of uniting feveral light objects into one great 
mafs. 
The management of light and Ihade is the moft im¬ 
portant of the practical parts of the art; iince, without 
the true arrangement of .them, vain mult be every effort of 
the painter to produce a juft refemblance of thofe thing* 
which nature offers to our view, and which are the im¬ 
mediate objeCts of his ltudy. Outline is but as the fec- 
tion of a body ; and colour, a Ample unvaried colour, 
added to it, would (till in no wife increafe its value as the 
reprefentative of a fubftance; but let light and Ihade be 
fuperadded, and duly difpoled,. and what was a flat fur- 
face becomes apparently a rounded one, is relieved from 
its ground, and appears to Hart from the canvas. '• 
The fources of light are in faCt but two ; viz. the fun 
and fire ; but to the painter a variety of modifications of 
thefe two take place, and become equally feparate fources, 
with diftinCt qualities, both as to power and colour. 
Such, for inltance, are the moon’s reflecting power; that 
of the atmofphere when the fun is hid ; and likewife the 
illumination proceeding from a window into a room. 
The effeCts produced by each of thefe differ fo widely 
from thofe of the two former, that we may fairly fay 
there are five general fources of light, at lealt, applicable 
S N «.o> 
