Pa N 
- NATURE 
on 7a ey 
[March 9 1882 — 
After a time they die. Their ill-health under these cir- 
cumstances is apparently due not merely to the want of 
food, since with sufficient trouble the small Entomostraca 
on which they feed can be supplied to them, but to the 
very fact of isolation in a small receptacle. They require 
a large bulk of water. Fluviatile organisms can be kept 
in a small vessel by means of a constant stream passed 
through the vessel, and organisms which inhabit small 
ponds present no difficulty. But lacustrine forms are very 
difficult to deal with. Should the Medusz reappear this 
year, it is my intention (with the permission of the authori- 
ties) to partially submerge a vessel with freely perforated 
sides in the large tank, the bottom of such vessel to be im- 
perforate, and the vessel itself two feet in diameter and 
three feet in depth. If a sufficient number of the first brood 
of young Meduse can be cultivated in this vessel through 
the summer, both males and females (unless the females 
have some altogether unsuspected history) will in all 
probability arrive at maturity, and reproduce in it as they 
clearly enough have done in the Regent’s Park tank 
between 1880 and 1881. It will then be possible from 
time to time to examine carefully the contents of this 
experimental vessel. I need not say that I should be 
very glad if others would carry out a similar experiment. 
E. RAY LANKESTER 
ELECTRICITY AT THE CRYSTAL PALACE 
I].—L£dison's Electric Light 
HE centre of attraction at the exhibition of electricity 
in the Crystal Palace, formally opened on Saturday 
by the Duke and Duchess of Edinburgh, will unques- 
tionably be the show of Mr. Edison. His electric light 
in the Entertainment Court and the Concert Room 
is by far the finest ever yet made, and is of itself 
a spectacle to be remembered. No expense has been 
spared to demonstrate the power and beauty of his 
incandescent lamps, and the divisibility of the current 
to meet the wants of domestic lighting ; while Messrs. 
Verity and Sons have seized the occasion to illus- 
trate their skill and show how eminently adapted the 
electric light is for ornamental purposes. The heated 
filament of carbon inclosed in a vacuous bulb of glass is 
well fitted for all kinds of domestic illumination by reason 
of its pure and absolutely steady glow, its healthiness and 
freedom from noxious fumes, and its comparative cool- 
ness. But in addition to its superiority over gas, oil, and 
candles in these respects, the Edison exhibit also proves 
in the most striking manner its superiority as a decorative 
light, and its unrivalled capacities for enhancing the 
artistic pleasures of our homes. Besides giving off no 
deleterious gases to tarnish gilding or dim the most deli- 
cate colours, the incandescent lamp lends itself to the 
designer’s fancies in a way which no other illuminant 
can ; and we may expect something like a revolution in 
household decoration by its introduction, as well as a new 
development of the brass-worker and the glass-blower’s 
art. 
Before considering the apparatus employed by Mr. 
Edison at the Crystal Palace for the production and dis- 
tribution of the light, we shall briefly describe the results. 
To begin with the Entertainment Court, which is in 
reality a small theatre, the principal object of interest is a 
magnificent chandelier suspended from the middle of the 
ceiling. This beautiful object is in itself a work of art, 
and sustains ninety-nine incandescent lamps. It is coni- 
cal in general shape, and is about fifteen feet in height by 
ten feet in diameter at the lower end ; while its weight is 
half a ton. In device it represents a tapering bouquet 
of flowers rising out of a golden basket. The stem of 
each flower springs from a circular brass plate within the 
basket, and bends over towards the spectator, presenting 
to him its calyx of coloured glass, in which is fixed an 
incandescent lamp. The foliage is all of hammered 
brass, richly gilt, and here and there is mingled with the © 
sun-flower or tiger-lily, and some rambling sprays of fern. 
The corollas of the flowers containing the Jamps, and 
acting as their shades, are in the form of heaths and 
harebells, made of glass, and tinted with a variety of 
colours—pearl, white, ruby, clear olive, and clouded blue. 
Each lamp projects from the heart of the flower like an ~ 
enlarged pistil, and throws its light outwards and down- 
wards into the room below. The lights are controlled in 
three sections by turncocks, like gas, and thus a graduated 
effect can be obtained, or all the lights may be put on or 
off at will. 
On each side of the stage, which is furnished with 
a row of twenty-four footlights, there is a pretty can- 
delabra! mounted on a short marble column, and repre- 
senting a rose-bush springing from a golden urn. The 
stem of the bush is entwined with China roses, and 
crowned with five upright lamps or candles, like the fruit 
of the tree. On the left of the stage is hung an exquisite 
little chandelier or lustre of Venetian glass, which, though 
far less imposing than its gaudier neighbour in the centre 
of the hall, is chaster and more elegant, and better fitted 
for an ordinary drawing-room. It is about four feet high, 
and consists of loops and festoons of crystal drops on 
gilded chains, encircled at the bottom by a ring of four- 
teen lamps ; and inclosing higher up a single incandescent 
bulb of ruby glass under a bell shade of the same material. 
The use of coloured glass for the vacuous bulb itself is 
illustrated here, and shows how the light can be tinted to 
harmonise with any interior furnishing, or suit the taste 
and eyesight of individuals. The brilliance of the glowing 
carbon in a transparent bulb is not too strong for the 
ordinary eye to look at with impunity; but persons of 
weak sight may have it reduced by the use of clouded 
bulbs, and students, or those suffering from diseases of 
the eye can employ bulbs of green or blue glass. Photo- 
graphers, too, can have recourse to ruby lamps in the 
development of their negatives. 
On the right side of the stage there is a third chandelier 
of gilt brass, with twelve naked bulbs, a number of single 
lamps on stands or movable brackets, like gas-jets, with 
turn-cocks, and either naked or shaded by flat conical 
reflectors of opal glass. Specimens of these are shown 
in Figs. 1 and 2. Then there are hall-lanterns of 
brass, inclosing clusters of bulbs, window-lights, a very 
handsome billiard lamp, containing six set of twin lamps, 
shaded from the eyes of the players by opal glass re- 
flectors and crimson fringes, and two handsome drawing- 
room shade-lamps of the same pattern, each containing 
a cluster of eight bulbs inside, and one being supple- 
mented by four pairs of naked bulbs outside. Bulbs are 
also shown burning under water, either clear or tinted, to 
illustrate the use of the incandescent system in fiery 
mines, and there is a specimen of a regulator lamp by 
which the power of the jet can be graduated at will like a 
gas-flame, by simply turning the cock. This lamp is 
shown in Fig. 3, the lower being the regulator, which 
acts by inserting the resistance of a series of vertical 
carbon rods into the circuit. This is done by turning 
the screw-piece at the base of the cylinder inclosing the 
bars. The cylinder is perforated to allow the air to 
circulate and keep them cool. 
In the top of the lamp the novelty is the form of the 
contact surfaces to prevent sparking or breaking the cir- 
cuit. These are conical, the small cone seen on the top 
of the figure being forced away from a conical cup on 
turning the screw plug. The large surfaces of the cones 
prevent simultaneously separating, and prevent a large 
spark. A safe-guard forthe lamp against a too powerful 
current is provided in a short lead wire, seen running 
across the left of the figure. When the current is too 
strong this wire fuses, and the current of the lamp is 
interrupted. 
® Electrolier and electrolabra weuld be the corresponding terms. 
