The sun. [volume] (New York [N.Y.]) 1833-1916, 1884-08-24

Of practice. but Into tho laboratory. a French
physicist repeated DAVIS experiments and
arrived at the conclusion. now generally I'D
mitted. that electricity could produce no
current. and consequently no voltaic arc. In
an absolute vacuum. When. however. the
attempt was made to turn from laboratory
work to practical applications host Of diff
culties were encountered. Nevertheless. in
1sil and 1874 two French savnnts obtained
some astonishing effects IN Paris by developing
the electric are In Q closed vessel which had
been exhausted Of air In order to retard the
combustion OF the carbons Their hope was 40
TO increase the power OF their apparatus rs to
create little suns for the use OF cities not favor
ed by the real one. But In 1874 this idea was
still only a dream. for no batteries strong
enough to illuminate large areas could be con-
structed at any price. and carbons CAPABLE OF
giving good light for a sufficient period woro
unknown. Probably the first trial Of ordinary
lighting by electricity on an extended scale
was made in 1a47. at Sunderland. by W. L.
Static. who Sftsrward repeated his experiments
in other English cities. But In 1852 Static
died. and. rs far a. England was concerned. 1t
seemed for many years that his projeot had
porished with him.
In France. on tho other hand. the attention
OF scientists was concentrated on the problem
bons are burned up during the passage OF tho
electric current. and thus grow shorter. some
means must be found OF bringing them together.
In 1855 two Lyonose patented u form Of reRu-
lator In which the lower carbon rested ON COL
umn OF mercury which, by the aid Of a special
mechanism. raised up the carbon In proportion
TO the rate OF its combustion. Some public ar-
pications OF this regulator In Lyons and
Paris excited great enthusiasm. but little by
little the interest In the subject waned and not
much was again heard OF 1t until 1860. The
principal remaining obstacle was the INSULT
cheney Of the means for generating electricity;
but finally, in 1870 tho inventor Of the Gramme
dynamo-electric machine placed at the dis
posal Of engineers as powerful n generator as
could be wished for. and six years later tho
Jablochkoff candle gave them u burner 80 sim
pie In construction that 1t was ut once accepted
in everyday practice. The first employment
Of this candle on large scale was in tho light
Ing OF the Avenue do rOpGra during tho Expo
siton OF 1878. and the Jablochkoff burner Is
used for the same purpose to this day. Hero
ends the Introductory chapter OF the history OF
the electric light which now passes from the
stage OF elaborate and costly experiment into
the wide field of industrial applications.
Let US now glance ut the decided improve
ments In the methods Of producing incandes-
cence and in the processes OF regulation which
have 80 strikinvly distinguished tho Inst ten
years. In three directions invention hns been
busy and triumphant: In periecting. firstly the
incandescent lamp: secondly. tho dynamo
electric generator; aud thirdly. tho regulator.
After discussing the lamps devised by Edison.
Maxim. swan. and Lane Fox. the authors OF
this treatise insist thu: the great superiority
Of the incandescsnt lamp IL not yet adequately
rApn vnH Wn 10, hnor
hare it with the arc lamp and animadvert on
it's relative ineiilciency. But We are reminded
that even In this respect it SURPRISES
gas far moro than the arc lamp does
IL. for by the tests made at Paris in 1881 tho
comparative efficiency Of these two ilumina-
tors IL ~ ono TO seven. The direction to be
followed by efforts to stlll further improve the
incandsscent lamp IL plainly indicated in this
volume. 1t has unQuestionably taken its final
form-that OF strip Of resisting material en-
closed In an exhausted glass envelope. Here
after attention must 10 fixed on tho incandes-
cling strip itself. with the aim Of giving it in
creased ability to Withstand the disinteGratinG
effects OF high temperatures and the disrupt.
Ing action OF the current. This particular
problem Ia. OF course. but partly electrical. be-
ing mainly concerned with a consideration OF
tho structural characteristics OF bodies upon
the nature designated depends.
In another chapter OF this book tho Gramme
dynamo-electrI machine is studied in conncc-
ton with the subsequent dynamos constructed
ty Hetfner Won Altsneck. Ferranti. Weston.
Maxim. Edison. and Brush. We quote some Of
the remarks on the last named three genera
tors. In Hiram \. Maxim's machine the field
magnets are identical with those OF tho Sie-
mems continuous current machines devised in
lS7. by Altensckl and the armaturo is u Pac-
notti and Gramine ring little elongated: but
what is most Interesting is the general ar
rangemsnt adopted to obtain with these ma
chimes combination suited for lighting by in
candsscence. and the current regulator invent
ed by MIR. Maxim to maintain the production
OF lighting current In exact proper
ton to the demand made upon 1t. 1t FORMS
with the lamp Of the same inventor. q
complete system In which all the con-
ditions OF the problem seem fulfilled"
A gap In the original exposition OF
the subject 10 filed ny by the American edi-
tor. who inserts a careful analysis OF tho Edison
dynamo. This machine il also of the Sic
mems continuous type. though 1t dirers from
it In constructive details. Being designed to
work on circuit Of low resistance. It was ne
cessary to make the resistance of the arInaturs
AS small as possible. and to 10 this and yet get
sufficient electro motive force. Mr.. Edison
sought to mako the magnetic field Of great
strength. To this end no has constructed his
field magnets much more massive than those
OF other machines. and has greatly Increased
the length OF the cores and the wire wound on
them. Besides giving stronger
field. large magnets have the adyan-
tage Of greatly increased magnetic stu.
biity. al extremely important condition In
securing steadlncss Of the lights" The
French authors themselves gave consider
able space 10 an account OF the Brush
machine. but tho American editor appends
clearer and more concise explanation
The armature OF tho Brush dynamo
"a RINK in form. not entirely overwound
with coils. but having projecting teeth
between tho coils like the Pncinotti rng-is
unique" In tho srmaturcs OF Siemnns, Gramme.
and Edison tho successive sections are
united In serlea all the way round and constI-
tute in one sense a continuous hobbin Hut in