230 
say that the prescribed conditions having been rigorously 
complied with, it was found, after many troublesome ex- 
periments, that when the vacuum within the lamp globe 
was good, and the contact between the carbon and the cone 
ductor which supported it sufficient, there was no blackening 
of the globes, and no appreciable wasting away of the 
carbons. . 
Thus was swept away a pernicious error, which, like a 
lying finger-post, proclaiming “ No road this way,” tended 
to bar progress along a good thoroughfare, 
It only remained to perfe&t the details of the lamp, to 
find the best material from which to form the carbon, 
and to fix this material in the lamp in the best manner, 
These points, I think, I have now satisfactorily settled; 
oy you see the result in the lamp before me on the 
table. 
It is a very modest looking affair, but its performance 
goes beyond its appearance. The carbon is extremely 
thin—a mere hair,—and how wonderfully strong and 
elastic it is I will endeavour to show you by means of the 
lantern. 
This carbon unlike the carbon spoken of by Fontaine, 
in the extract I read to you, is quite homogeneous and 
almost flinty in hardness, and it becomes harder by use in 
the lamp; the longer and the hotter ‘it is heated, the 
harder it becomes, What degree of hardness it will ulti- 
mately arrive at is an interesting question. 
Here is a magnified view of the carbon ring in a state 
of incandescence ; observe how absolutely uniform in 
brightness it is; that proves it to be homogeneous and 
foretells its durability. 
Now I will show you how easily lamps of this kind are 
lighted, and how completely this form of ele@ric light can 
be divided and distributed. 
Is it not a pleasant light ?* It is not so white as the arc 
light, but yet a whiter light than gas. Colours are correctly 
seen by it, as this piGure shows. But the great merit 
of this light consists in its not being in contact with air, 
and therefore there cannot possibly be the slightest air 
pollution caused by it. The rooms in which this light is 
used will be as pure by night as by day. 
It is essential to economy in lighting by incandescence 
that the incandescent carbon should be very thin, The 
carbon I use is not cne-twentieth the thickness of the 
thinnest of the carbons formerly employed, and therefore 
one-twentieth of the current, costing one-twentieth the 
price, will produce in my thin carbon the same degree of 
luminosity as twenty times more current will produce in 
such carbons as were used in those ancient lamps. 
You will notice that in my lamp leakage is very thoroughly 
guarded against. The wire which passes through the glass 
not only having the glass fused around it where the wire 
and globe meet— but in addition to this, the wire is coated 
with glass almost up to. the carbon. In this way the 
vacuum is preserved very effectually. 
You have, of course, all heard that after Mr, Edison 
abandoned his platinum lamp as impracticable, he invented 
a new lamp in which carbonised cardboard is used. 
Here is a diagram of Mr. Edison's carbon lamp, with its 
horse-shoe of carbonised paper. It is in some resped@s 
like mine, but latterly I have given up the use of carbonised 
cardboard, and am now using a material as much better 
than carbonised cardboard as carbonised cardbcard was 
better than the material previously used. In an article 
which appeared in the February number of Scribner's 
Magazine, authenticated by a letter from Mr. Edison in 
the same publication, it is stated that Mr. Edison was the 
first to use carbonised paper; that is incorre®. And this 
also occurs after a description of the Sprengel pump used 
in exhausting these lamps : —* Mr. Edison’s use of carbon 
in such a vacuum is entirely new.” Now I daresay there 
are many here who will remember this little lamp, which 
I showed here two years go in action. ‘This lamp has 
exactly the same simplicity as my present lamp, being 
composed entirely of three substances, namely, glass, 
platinum, aud carbon, and it was exhausted in precisely 
we y i . ‘ 
Electric Lighting. {Crm pws, 
the same manner, and to the same degree, as that which 
Mr. Upton—no doubt in good faith but still in error— 
speaks of as ¢ entirely new.” 
I do not mention these things in any way to disparage 
Mr. Edison, for no one can esteem more highly his in- 
ventive genius than I do. I merely state these fas be- 
cause I think it is right to do so in my own interest, and 
in the interest of true history. 
The complete seclusion of the light in this lamp from 
contact with air suggests its adaptability to coal mine 
illumination, and I earnestly hope that this may prove to 
be one of its uses. 
But the great purpose to which a lamp of this kind is 
applicable is the lighting of your houses. In view of such 
an application—two all-important questions present them- 
selves:—one, as to distribution, another, as to cost. 
Can this light be divided, distributed, and measured as 
gas is divided, distributed, and measured? And at what 
cost? It is quite impossible in a brief leure to discuss 
these questions exhaustively, but as far as is possible, in 
a few words I will answer them. 
1st. Then, as to division and distribution, it has been 
asserted on very high authority that great loss necessarily 
attends the division of the ele@ric light. To a certain 
extent this is true of lighting by the eledric are, but it is 
totally and absolutely erroneous of lighting by incan- 
descence. There is no less in dividing the electric light 
produced by this means. Faraday has stated the law of 
the case in these words: An elecric current which will 
heat one inch of wire whife hot, will also heat to the same 
temperature 100 inches, or an infinite length of the same 
wire.” There is no question of the truth of this. Now, 
as it is only necessary, in order to maintain a given current, 
to increase the force which produces it in the same pro- 
portion as you increase the resistance to its flow, it follows 
that the cost of raising to a certain degree of incandescence 
a longer or shorter length of carbon or of maintaining a 10 
candle-light or 100 candle-light will be exa&ly proportional 
to the light produced. You may even contemplate on this 
principle the economical production of an elegric light as 
small as a rush-light, "A certain unit of light may be 
established in an indefinite number of places, with no 
greater aggregate expenditure of power than that diredly 
and simply proportional to the number of light. 
With regard to distribution, I believe that it will prove 
:0 be pradticable to light any large town—all Newcastle, 
for instance-—by means of wires laid in the ground as gas- 
pipes are laid, and all branching from one centre, and con- 
veying the ele@ric current to lamps like this. 
The lamps now lighted are supplied by a current coming 
{rom generators working at the far end of Mosley Street 
(a quarter of a mile away), and it would be just as easy by 
asing a more energetic current—a current, as it were, 
ander higher pressure—to maintain these several miles 
away, and for this purpose the conducors need not be 
large, not so large certainly as to make the distribution of 
sledric current more costly than the distribution of gas. 
For supplying large towns with eledric light, Mr. Edison 
proposes to have a number of centres for the supply of 
eleciric power, perhaps a quarter of a mile apart, whence 
wires would be sent out in every different dire&ion, distri- 
buting the current to the houses round about. His plan 
of distribution is this. He proposes to send out bundles 
of main wires from each of the centres of supply, and from 
these main wires to branch as many small wires into the 
houses as there are lamps to be lighted, each branch wire 
proceeding from a main wire to the place where the lamp 
is situated, and from thence to a return main wire. 
Now although this plan has the great merit of simplicity, 
[ do not think it will answer, except for very short dis- 
tances. 
When a number of lamps are grouped together in that 
manner, it is necessary that the individual lamps should 
offer a very high resistance to the current, for if each lamp 
doesnot offer an extremely high resistance to the passage 
of the current there must be great waste, a large propor