Fune 4, 1885] 
much has had to be compressed into so little space, to 
indicate the progress of invention in each class of each 
group. If, however, electricity is not represented in this 
way, it is in another way, and that is through the medium 
of one of its special applications—that of the electric 
light. Electricity thus forms the light and life of the 
whole Exhibition after sunset, and in this connection we 
would view it on the present occasion. 
Those who visited the Health Exhibition last year will 
not notice any great change in the internal illumination 
beyond the more extensive use of the electric light and 
its greater steadiness, but will observe that an alteration 
has been made in the garden lighting, to a description of 
which we propose to confine this article. In place of the 
numerous attendants who, a little before darkness set in, 
were to be seen last year lighting one by one the little oil 
lamps which, in their coloured glasses, were scattered all 
over the trees and lawns, an observer discovers at half- 
past eight or a little liter a gradual diminution in the 
darkness of the evening, and the eye becomes gradually 
sensible to the fact that the architectural features of the 
buildings are becoming clearly defined, and by degrees 
are actually illuminating surrounding objects, whilst at the 
same time the lawns and shrubberies, the parterres and 
trees, and even the ponds of water and waterfalls assist in 
the general illumination with light of every shade and 
colour. Where before all was darkness, there is a scene 
of bewildering enchantment: fountains play and throw 
up into the air, now high, now low, solid sheets of illumined 
water and spray of mingled water, dust, and light, at one | 
moment of golden hue, at another of the loveliest magenta ; 
while when the silver light of the electric arc alone illu- 
minates the fountains, broken by some magic power below 
into waterdrops, all the prismatic colours of the rainbow 
are observable, and, revelling in the beauty, one wonders 
how it is all brought about. 
In what is known as the tower, Sir Francis Bolton has 
before him a plan of the gardens with switches on it, 
enabling him to turn the lights on or off, or to increase or 
diminish their intensity at-his will. 
controls the effects in the upper garden, another those in 
the lower garden, a third commands the statue of the late 
Prince Consort, a fourth and fifth the illumination of the 
east and west quadrants and east and west arcades respec- 
tively, whilst a sixth controls the external lighting of the 
conservatory. Four switches on the lower portion of the 
switch board enable the operator to raise or lower the 
intensity of the light ; the first altering it from 1 to %, the 
second from 2 to 4, the third from } to 3, and the fourth 
from # to full power. 
One of the most interesting features of the illumination, 
and that which perhaps causes the most wonder and 
bewilderment, is the play of the fountains. Below the 
island in the fountain is a water-tight chamber, about 
5 feet in height and 20 feet square, into which one 
obtains access by first descending a ladder from the 
diving apparatus-house into a low arched passage, from 
which one ascends into the chamber. The roof of this is 
covered with water-pipes which convey the water from 
the main in all directions, the supply being regulated by 
screw valves ; the five large jets are fitted with plug valves 
and levers, by the manipulation of which the dancing 
motion and breaking up into water-drops of the columns 
of water are effected. The average quantity of water 
expended per hour during a fountain display is 70,000 
gallons. Under the five large water jets are five sky- 
lights, fitted with thick glass, below each of which is 
placed a wooden box, containing a powerful arc-light 
with the carbons set horizontally. Over the top of the 
lantern is a holophote, such as is used in lighthouses, by 
means of which the rays of light are concentrated, and 
projected upwards into and with the column of water, 
whilst their colours are varied by drawing sheets of stained 
glass across the lantern. The water is supplied at a 
NATURE 
One of the switches | 
107 
pressure of about 7olb. to the square inch, which is 
sufficient to carry it up to a height of 120 feet. 
On one of the walls of the chamber is a board, on 
which are signalled the instructions from the tower, which 
are read off by an assistant to the staff. In this manner 
the various effects which more or less puzzle the spectators 
are telegraphed from the tower above, and carried out in 
the concealed chamber below. 
The following are the number and distribution of the 
lamps, all of which are made by the Edison-Swan United 
Company, most of them being of 5 and ro-candle power, 
whilst a few of 20-candle power are used on the band 
stands and verandah of the conservatory :— 
Lamps 
Conservatory acc 1418 
E. and W. Quadrants 1584 
E. and W. Arcades 1832 
Upper Gardens 1550 
Lower Gardens 2300 
Albert Statue 336 
Total on 9020 
There are fourteen miles of main and branch wires, nine 
miles of twin wire, and two miles of small connecting 
wire. On the buildings and on straight lines on the grass 
specially constructed wooden lamp-holders are used, in 
other places ordinary spring-holders. The current is 
generated by three Siemens B 13 self-regulating dynamos, 
each weighing about 11 tons, and each capable of main- 
taining 2000 (20-candle) lights at 300 revolutions per 
minute ; the current of each being 500 amperes at an 
electromotive force of 250 volts, the weight of the arma- 
ture being 3 tons. The dimensions of the machines are 
as below :— : 
in. 
Heigit including bed-plate 
Length over all... Be 
Width 50K 
Diameter of armature 
Length of armature 
Wn oOMD 
nu wow 
The four series coils, which are coupled in parallel, are 
wound with copper-wire 4-1oths of an inch in diameter, 
and the shunt coils, which are coupled in series, with wire 
of No. 9 standard gauge; the armature being wound 
with flat strips instead of wire. Each of the dynamos is 
coupled to a Goodfellow and Matthew’s triplex compound 
engine of 200-h.p. indicated, two of the machines being 
easily capable of maintaining all the lights. The main 
current from the dynamos is led to a switch-board, in 
connection with which is an electro-dynamometer so 
arranged that there shall be no break of continuity. In 
each branch circuit is a fork working in the core of a 
solenoid, the prongs of the fork dipping into a pair of 
mercury contact cups. The solenoids are connected by 
wires with Sir Francis Bolton’s room, and by their use he 
can raise or lower the fork out of or into the contact cups 
and thus turn the lights off or an as required. The return 
circuits enter into a single conductor, which is arranged 
with four sets of mercury cups and solenoids in series ; 
around each set is a bye-pass containing a resistance of 
determined magnitude, so as to vary the brilliancy of the 
lamps as desired. 
The works for the electric illumination of the gardens 
and fountains have been carried out by Messrs. Siemens 
Brothers, to the designs of Sir Francis Bolton. Con- 
sidering that the instructions for the preparation of the 
machinery for illuminating the gardens were only given 
in February last, the result obtained at the Inventions 
Exhibition is evidence that electric lighting has now 
advanced to such a stage that orders may be given for 
very large installations and executed in a perfect manner 
in a very short space of time. 
