1801.] 
and refraction of light, any-kind of illu- 
mination in any direétion may be enfured. 
As an example of the fmpler kind in this 
very ingenious apparatus, we fhall men- 
_ tion the conftruction of a common ftreet- 
lamp; as propofed by the Patentee. The 
‘burner is placed behind three’ cylinders of 
glafs, one ‘of which is oppofite to each 
fide of the pavement, and the centre glafs 
to’ the middle of the ftreet. The fide 
glaffes, as they have to illuminate a greater 
diftance than the ceritre, are ‘put at three 
inches diftance from the flame, whilft the | 
latter is only two inches, and thus ‘both 
-the fides and centre of the ftreet is lighted. 
As, however, there will be two dark 
{paces between the illuminated part of the 
ftreet, corre{ponding with the intervals on 
each fide of the centre glafs refracter, 
two mirrors may. be placed above and be- 
hind the fide giafics to fupply this de- 
ficiency. ; 
The glaffes may be either folid or hol- 
low, and filled with a clear fluid. They 
are fecured in a tin frame, and covered 
above with another tin frame, and the 
whole chamber of the glaffes fecured from 
fmoke and duft, by being enclofed in a 
cement, or by platter of Paris. The in- 
ventor has, befides, conftru€ted the lamp 
in a convenient manner for being trimmed 
and cleaned, and has added a great variety 
of contrivances for particular ules, which 
it is not neceffary to mention. He. ex- 
pects that, if they are employed for the 
purpofes of lighting the ftreets, half, or 
at leaft one third of the prefent number 
will be fufficient, and that an interval of 
120 feet may be Jeft between each. 
Objervations.—Among the more obvi- 
ous objections to this highly ingenious 
plan which at fir fuggeft themfelves, 
three may be enumerated. The firft is 
the greater rifk of damage and accident-in 
an apparatus fomewhat complicated when 
daily handled by common lamp-lighters, 
notwithftanding their well-known dexte- 
rity. The fecond is, that if any number 
fhould be broken, or out of repair, :efpe- 
cially two or three in fucceflion, a confi- 
derable length of ftreet might be left for 
fome time quite dark, -efpecially with 120 
feet interval between each damp. The 
third is the inconvenient and unpleafant 
glare on the eyes of the paffenger,, which 
is fo often complained of in the prefent 
water-lamps, and which would hardly be 
entirely removed even by this improve- 
ment. It fhould be remembered, that 
the purpole of illumination is fometimes 
only for the convenience of the perfon_or 
body where the light is fixed, in carriage- 
New Patents lately Enrolled. 
a 
lamps or portable lanterns; but at other 
times, where every fubject within the 
fpread of the light is to receive. benefit 
from it, the mode ef cafting light, and 
its contraft with the furrounding fhade, 
are not matters of indifference. 
Ee 
WILLIAM PLAYFAIR, 0f LONDON, for an 
INVENTION, by which SHIPS are en- 
abled to SALL FASTER than they now do 
iz @ HEAVY SEA, &e. 
This invention .confifts in placing on 
the bow of the fhip, or on fuch part of it 
as the oppofing wave ftrikes, a /hield or 
water-fkreen, between which and the fhip 
are {prings to let it retire back upon the 
fhip in fuch a manner, as that the time 
during which the wave atts is prolonged, 
and that hard crafh prevented that takes 
place againft thofe fhitps which have not 
fuch a protection. ‘This fhield or fkreen 
is fo made, as to be without difficulty 
placed whenever the wave happens to 
ftrike, and changed from that to any other 
when circumftances require it. The 
fhield is above the water-line when the 
fhip is in a horizontal pofition, being only 
under water when the wave comes, fo that 
it may not impede the failing of the veffel, 
by making’ it cut the water with more 
difficulty, when there is no water to op- 
pofe it. ‘ 
Objervations.—It is well known, by 
the effects of fpring-carriages as well as 
by the refiftance that elaftic fubftances give 
even to the moft violent fhocks (even can- 
non fhot) that much may be effected by 
interpofing an elaftic fubflance between two 
bodies moving in oppofite directions. It 
is well known alfo, that water is a hard 
body when ftriking or ftruck fuddenly, 
and that. prolonging the time of collifion 
diminifhes greatly the effect produced by 
the blow. 
Theelafticity of the French veffels rather 
than any fuperiority of form, has for fome 
time been believed to occafion their quick 
failing. The well known fac, that velf.ls 
fail fafter atter they have been ftrained (if 
not ftrained too much) than taken quite 
Riff from the ftocks, alfo augurs well, 
and in favour of this invention, of which, 
however, the real utility remains to be 
proved by experiment; and finally, by 
putting it in practice. 
As the object is immenfe to a country 
like this, the profperity and fafety of 
which depend on its naval fuperiority, 
there can be little doubt that every jutftice 
will be done to this invention, and that if 
4s found ufefal it will amply reward the 
inventor. 
ACCOUNT 
